Will my car battery charger work for trolling motor battery? 2024

Largemouth21 reply :

I have this battery charger that I use for car battery's and my ATV battery. Will it work ok for a 125AH 12 volt lead acid deep cycle marine battery? I read some chargers can shorten life of battery. Thanks for answering all my questions

cfalco reply :

Yes it will work, as far as some chargers hurting batteries I am guessing that if one leaves it on all the time it will at some point damage the battery. That does not look like a smart charger (which would stop charging when the bat is charged) so be careful about how many hours or days you let it sit on there. Years ago when I charged that way I would put it on when I went to bed at night and take it off when I left so it sat overnight.

IndianaOutdoors reply :

It will work. Same as charging a dead car battery. Just don't leave it on too long or you'll burn up the battery. I recommend using a smart charger. It's a set and forget deal. Turns off automatically and always gives the right amount of charge. It's nice but not necessary.

Largemouth21 reply :

On 8/23/2017 at 1:04 AM, IndianaOutdoors said:

It will work. Same as charging a dead car battery. Just don't leave it on too long or you'll burn up the battery. I recommend using a smart charger. It's a set and forget deal. Turns off automatically and always gives the right amount of charge. It's nice but not necessary.

On 8/23/2017 at 12:31 AM, cfalco said:

Yes it will work, as far as some chargers hurting batteries I am guessing that if one leaves it on all the time it will at some point damage the battery. That does not look like a smart charger (which would stop charging when the bat is charged) so be careful about how many hours or days you let it sit on there. Years ago when I charged that way I would put it on when I went to bed at night and take it off when I left so it sat overnight.

what would be your guess as how long to leave it on for? The charging gauge works I think so I can watch that.

IndianaOutdoors reply :

Depends on how low the charge on the battery is. At 6 amp charge rate it's gonna take a while for that big battery if it's really low. Just watch the gauge the first time you charge it. Well check it occasionally anyway and time it. Just did some rough Google math. At 80% discharge and 6amp charge re ate it will take about 16hrs to charge. If you bought a 15amp charger it would only take 6hrs. This is what I use. ://www.amazon.com/gp/aw/d/B000H961YI/ref=sxbs_sxwds-stvp_2?ie=UTF8&qid=1503425075&sr=2&pf_rd_m=ATVPDKIKX0DER&pf_rd_p=2972396462&pd_rd_wg=WURpu&pf_rd_r=VWW1XTVVBTDGWWM76F66&pf_rd_s=mobile-sx-bottom-slot&pf_rd_t=9701&pd_rd_i=B000H961YI&pd_rd_w=jtp3f&pf_rd_i=schumaker+charger&pd_rd_r=YS959GET7JA6N0ARWZ21&pi=AC_SX236_SY340_FMwebp_QL65

Largemouth21 reply :

On 8/23/2017 at 2:05 AM, IndianaOutdoors said:

Depends on how low the charge on the battery is. At 6 amp charge rate it's gonna take a while for that big battery if it's really low. Just watch the gauge the first time you charge it. Well check it occasionally anyway and time it. Just did some rough Google math. At 80% discharge and 6amp charge re ate it will take about 16hrs to charge. If you bought a 15amp charger it would only take 6hrs. This is what I use. ://www.amazon.com/gp/aw/d/B000H961YI/ref=sxbs_sxwds-stvp_2?ie=UTF8&qid=1503425075&sr=2&pf_rd_m=ATVPDKIKX0DER&pf_rd_p=2972396462&pd_rd_wg=WURpu&pf_rd_r=VWW1XTVVBTDGWWM76F66&pf_rd_s=mobile-sx-bottom-slot&pf_rd_t=9701&pd_rd_i=B000H961YI&pd_rd_w=jtp3f&pf_rd_i=schumaker+charger&pd_rd_r=YS959GET7JA6N0ARWZ21&pi=AC_SX236_SY340_FMwebp_QL65

I can make due for a while, eventually I will probably pick up a nice one like the one you linked me to. Appreciate it

edit: unfortunately the link doesn't seem to be working. I won't be getting a new charger for a while anyway but not sure whats going on with my device here

Edited August 23, 2017 by Largemouth21

Hez reply :

This charger will not charge your deep cycle batteries to their fullest potential. This charger is great for dead CRANKING batteries.

Deep cycle batteries are built differently, and need to be charged with a "Trickle" charger.

Largemouth21 reply :

On 8/23/2017 at 2:25 AM, Hez said:

This charger will not charge your deep cycle batteries to their fullest potential. This charger is great for dead CRANKING batteries.

Deep cycle batteries are built differently, and need to be charged with a "Trickle" charger.

*sigh* how much money will I have in this

padon reply :

it will charge your battery but as HEZ said its not ideal. deep cycle batteries should be charged at 2-3amps over a longer time period. I just bought a charger recently at walmart 9forget the brand) that will charge on 2 or10 amps and can be left hooked up. it will kick off when fully charged the turn back on when charge drops below 95. it is also small and extremely light. it was 50 bucks I really like it.

Largemouth21 reply :

On 8/23/2017 at 2:25 AM, Hez said:

This charger will not charge your deep cycle batteries to their fullest potential. This charger is great for dead CRANKING batteries.

Deep cycle batteries are built differently, and need to be charged with a "Trickle" charger.

can I get away with something cheap like, cabelas battery tender Jr.

On 8/23/2017 at 2:34 AM, padon said:

it will charge your battery but as HEZ said its not ideal. deep cycle batteries should be charged at 2-3amps over a longer time period. I just bought a charger recently at walmart 9forget the brand) that will charge on 2 or10 amps and can be left hooked up. it will kick off when fully charged the turn back on when charge drops below 95. it is also small and extremely light. it was 50 bucks I really like it.

I can look next time I'm there. You said 2 or 10 amps. When would you want 2 vs 10 amps

padon reply :

use the 2 or 3 amp setting for deep cycles trolling motor etc. cranking batteries can be charged on 10 amps

Largemouth21 reply :

On 8/23/2017 at 2:41 AM, padon said:

use the 2 or 3 amp setting for deep cycles trolling motor etc. cranking batteries can be charged on 10 amps

Okay, makes sense

Way2slow reply :

yes, it will work, just like a paddle will work for moving the boat around. Is it the best tool for the job, not by a long shot.

First, the charger is too small, second, using that type of charger is just causing a slow death of your battery.

To properly charge the battery, the charger should be approx. 10% of the rated capacity. That's 10 - 15 amps for most TM batteries.

Second, those chargers are only intended to charge a battery every now and then, not constantly keep charging the battery every time its used. Their voltage output is not suitable for that and actually cause harm to a battery every time you charge it. Also, to fully charge a battery, it has to be overcharged slightly, those chargers are not designed to do that, as soon as the battery reaches a certain level, they shut off if it's and automatic, or can easily over charge one if not disconnected about 10 - 20 minutes after the battery reaches 100%.

To properly charge a battery that's recharged on a regular basis, you need to use one that's logic controlled. The stand alone chargers that do this are usually sold as Logic Controlled, Smart Chargers or Intili Chargers. Many also have a maintenance mode so they can be left on the battery 24/7 and keep it properly maintained. Some of the cheaper ones that advertise this feature will actually fry the battery in several months because their maintenance voltage is not that well regulated and too high to leave them on 24/7.

A good charger will pay for itself on the first battery. You might get a year out of a good battery with a cheap charger, and five or six years with a good charger.

Bad info, don't use the 2 - 3 amp setting, it needs to be closer to 10. A battery must gas a little bit when charger to keep the electrolyte mixed. A slow charge like that will not make it form gas bubble and the electrolyte will stratify, causing the acid to settle to the bottom and water in the upper layer. The heavy concentration of acid eats up the bottom section of plates.

Hez reply :

On 8/23/2017 at 2:58 AM, Way2slow said:

yes, it will work, just like a paddle will work for moving the boat around. Is it the best tool for the job, not by a long shot.

First, the charger is too small, second, using that type of charger is just causing a slow death of your battery.

To properly charge the battery, the charger should be approx. 10% of the rated capacity. That's 10 - 15 amps for most TM batteries.

Second, those chargers are only intended to charge a battery every now and then, not constantly keep charging the battery every time its used. Their voltage output is not suitable for that and actually cause harm to a battery every time you charge it. Also, to fully charge a battery, it has to be overcharged slightly, those chargers are not designed to do that, as soon as the battery reaches a certain level, they shut off if it's and automatic, or can easily over charge one if not disconnected about 10 - 20 minutes after the battery reaches 100%.

To properly charge a battery that's recharged on a regular basis, you need to use one that's logic controlled. The stand alone chargers that do this are usually sold as Logic Controlled, Smart Chargers or Intili Chargers. Many also have a maintenance mode so they can be left on the battery 24/7 and keep it properly maintained. Some of the cheaper ones that advertise this feature will actually fry the battery in several months because their maintenance voltage is not that well regulated and too high to leave them on 24/7.

A good charger will pay for itself on the first battery. You might get a year out of a good battery with a cheap charger, and five or six years with a good charger.

....the "Gospel"

This is what I use:

https://www.amazon.com/Battery-Tender-021-0123-Junior-Charger/dp/B000CITK8S/ref=pd_lpo_vtph_263_bs_t_1/131-1522934-7840100?_encoding=UTF8&psc=1&refRID=MSE2CCC64CM2N3AK8TJ7

Largemouth21 reply :

On 8/23/2017 at 3:03 AM, Hez said:

....the "Gospel"

This is what I use:

https://www.amazon.com/Battery-Tender-021-0123-Junior-Charger/dp/B000CITK8S/ref=pd_lpo_vtph_263_bs_t_1/131-1522934-7840100?_encoding=UTF8&psc=1&refRID=MSE2CCC64CM2N3AK8TJ7

Im confused, you agreed with him and he said 10-15 amps. But that charger is only .75 amps.

Hez reply :

The Amps statement I can not speak on - because I am not very educated in electrical terminology.

What the product that I linked does have, that does agree with Way2slow is:

Smart Microcontroller

Our onboard computer assures correct level of power is sent to the battery at all times.

ISM Adaptive Charging

ISM (Infinite Sequential Monitoring) adapts to the battery’s needs hundreds of times per second.

Connect and Forget It

Once connected, the Battery Tender manages your battery’s health on it’s own.

On 8/23/2017 at 2:29 AM, Largemouth21 said:

*sigh* how much money will I have in this

Based on this statement - I was trying to help you make a sound economical decision - and not damage your batteries at the same time...by suggesting a known working product (has been charging my deep cycle batteries going on 3 years)

Largemouth21 reply :

On 8/23/2017 at 3:16 AM, Hez said:

The Amps statement I can not speak on - because I am not very educated in electrical terminology.

What the product that I linked does have, that does agree with Way2slow is:

Smart Microcontroller

Our onboard computer assures correct level of power is sent to the battery at all times.

ISM Adaptive Charging

ISM (Infinite Sequential Monitoring) adapts to the battery’s needs hundreds of times per second.

Connect and Forget It

Once connected, the Battery Tender manages your battery’s health on it’s own.

Based on this statement - I was trying to help you make a sound economical decision - and not damage your batteries at the same time...by suggesting a known working product (has been charging my deep cycle batteries going on 3 years)

Yeah I will go with that one. i come from a family who doesn't like to spend money, especially if we think we can use something we already have to make a solution I will pick up a battery tender, they are cheap and the reviews are good! Thanks

Hez reply :

On 8/23/2017 at 3:22 AM, Largemouth21 said:

Yeah I will go with that one. i come from a family who doesn't like to spend money, especially if we think we can use something we already have to make a solution I will pick up a battery tender, they are cheap and the reviews are good! Thanks

And I guarantee you it will do the job sufficiently.

I actually have 3 (1 for each battery - 2 deep cycle and my Cranking battery). I opted for this route as opposed to an $400 3 bank onboard chager.

Largemouth21 reply :

On 8/23/2017 at 3:24 AM, Hez said:

And I guarantee you it will do the job sufficiently.

I actually have 3 (1 for each battery - 2 deep cycle and my Cranking battery). I opted for this route as opposed to an $400 3 bank onboard chager.

bit of a price difference there thanks for the help. Battery tender jr it is

Hez reply :

On 8/23/2017 at 3:37 AM, Largemouth21 said:

bit of a price difference there thanks for the help. Battery tender jr it is

Glad to have helped

fishnkamp reply :

I ran an all electric boat for reservoir fishing and on that boat were 5 deep cycles. One supplied a 12 volt trolling motor on the front deck. Then there were 4 more batteries feeding two transom mount 12 volt trolling motors. Each transom mount motor was a Minn Kota 55 pound thrust unit and it was fed by two batteries hooked up together. I use a total of 3 of these chargers and they did a terrific job. Wal Mart sells them for $45. All you need is one and use it every time you return home from fishing. Your batteries will last a long time.

https://www.walmart.com/ip/Schumacher-SpeedCharge-15-Amp-Automotive-and-Marine-Battery-Charger/13005745

WRB reply :

Way2Slow goes out of his way to write an excellent tutorial on deep cycle marine battery charging and most of you ignor it.

Tom

david in va reply :

On 8/23/2017 at 4:15 AM, WRB said:

Way2Slow goes out of his way to write an excellent tutorial on deep cycle marine battery charging and most of you ignor it.

Tom

Way2slow reply :

Thanks Tom, but it don't bother me.

I'm not the one buying the batteries.

My hope is at least one person will read some of this stuff I post and think maybe that's what they should do.

Two very popular thoughts I see constantly about batteries that is just totally wrong, one is the term "slow charge". Slow charge in the battery world is the 10% rate. Most automotive batteries, because they are cranking batteries can charge at 30-40 amps and are charged at that most of the time. How many times have you looked at the amp meter in you vehicle and see it on 30 or more amps after first starting it.

The other one is that makes my skin crawl is the one where people think you need to totally discharge a deep cycle battery before you charge it, and then charge it back at that stupid 3 or 4 amps or it will develop a "memory". The idiots don't realize, lead acid batteries can't develop a memory, that's only for the old rechargeable NiCads some of the lithium ion batteries Talk about destroying a battery, that's a great way to do that.

Since most probably don't even know what a cycle count is, they wouldn't understand doing that "GREATLY" reduces the cycle count, and charging at 75% capacity, greatly increases the cycle count.

NHBull reply :

Good info here......I had always used the rule 10 amps for 10 hrs was the initial charge for the season and let the smart charger do the rest.

IndianaOutdoors reply :

Not sure how much you were able to follow that largemouth21. But you do not want that trickle charger. Way2slow is right on the money. The blue 15amp schumaker charger is what you want. I totally understand what you mean about being from a family that doesn't spend money on things. That's how I grew up too. Took me a while to come around but having nice things and doing things the right way is just easier and better than messing with junk all the time. I know the cost can be intimidating but with a new battery and the right charger you should get years of trouble free use. If you can't swing the cost then do what you gotta do to get on the water. Just don't forget to have fun.

Largemouth21 reply :

On 8/23/2017 at 6:05 AM, Way2slow said:

Thanks Tom, but it don't bother me.

I'm not the one buying the batteries.

My hope is at least one person will read some of this stuff I post and think maybe that's what they should do.

Two very popular thoughts I see constantly about batteries that is just totally wrong, one is the term "slow charge". Slow charge in the battery world is the 10% rate. Most automotive batteries, because they are cranking batteries can charge at 30-40 amps and are charged at that most of the time. How many times have you looked at the amp meter in you vehicle and see it on 30 or more amps after first starting it.

The other one is that makes my skin crawl is the one where people think you need to totally discharge a deep cycle battery before you charge it, and then charge it back at that stupid 3 or 4 amps or it will develop a "memory". The idiots don't realize, lead acid batteries can't develop a memory, that's only for the old rechargeable NiCads some of the lithium ion batteries Talk about destroying a battery, that's a great way to do that.

Since most probably don't even know what a cycle count is, they wouldn't understand doing that "GREATLY" reduces the cycle count, and charging at 75% capacity, greatly increases the cycle count.

i don't ignore ANY posts. I sit down and carefully read through everything. I try to absorb as much information as I can from each post. I certainly learned a lot from you. I sincerely thank you for your time.

I was originally going to use the car battery charger. Im glad I asked on here because i was able to learn a lot about batteries and figure out a solution to help me save my batteries from dying early.

On 8/23/2017 at 7:46 AM, IndianaOutdoors said:

Not sure how much you were able to follow that largemouth21. But you do not want that trickle charger. Way2slow is right on the money. The blue 15amp schumaker charger is what you want. I totally understand what you mean about being from a family that doesn't spend money on things. That's how I grew up too. Took me a while to come around but having nice things and doing things the right way is just easier and better than messing with junk all the time. I know the cost can be intimidating but with a new battery and the right charger you should get years of trouble free use. If you can't swing the cost then do what you gotta do to get on the water. Just don't forget to have fun.

I agree with what you said 100%. I will keep working to get some money put together, Big thanks to everyone who contributed to this thread. I learned a lot

On 8/23/2017 at 4:02 AM, fishnkamp said:

I ran an all electric boat for reservoir fishing and on that boat were 5 deep cycles. One supplied a 12 volt trolling motor on the front deck. Then there were 4 more batteries feeding two transom mount 12 volt trolling motors. Each transom mount motor was a Minn Kota 55 pound thrust unit and it was fed by two batteries hooked up together. I use a total of 3 of these chargers and they did a tewrrific job. Wal Mart sells them for $45. All you need is one and use it every time you return home from fishing. Your batteries will last a long time.

https://www.walmart.com/ip/Schumacher-SpeedCharge-15-Amp-Automotive-and-Marine-Battery-Charger/13005745

45$ Not too bad. Thanks for linking it to me. I will pick one up

Largemouth21 reply :

On 8/23/2017 at 4:15 AM, WRB said:

Way2Slow goes out of his way to write an excellent tutorial on deep cycle marine battery charging and most of you ignor it.

Tom

I carefully read each and every post. I absorb as much information as I can from each thread. Way2Slow helped me out a lot today.

WRB reply :

On 8/23/2017 at 10:42 AM, Largemouth21 said:

I carefully read each and every post. I absorb as much information as I can from each thread. Way2Slow helped me out a lot today.

Positive feedback is why we try to share a little knowledge and thank you for responding.

Tom

padon reply :

well apparently the people at battery warehouse have been lying to me for 20 years telling me to use the 3 amp setting. communists. not surprising I guess since their job is to sell batteries. like fishnkamp I run a lot of batteries on electric only lakes so charging etc is important to me . I have a charger that will charge at 15 amps so I guess that's what ill use from now on. I do usually get 3 years out of my batteries so I guess its been working for me but it takes a long time to charge them.since ive been given wrong info on the charging let me ask this . ive been told by these same people that you should try to discharge the battery as much as possible them recharge immediately. any truth to that?

ok I read largemouth 21 post again. I see that is a lie too.which is good because I never knew how to discharge one anyway.i have zero knowledge of electronics so its a good thing I read the posts.another question then. how many years would you expect to get out of a battery with fairly heavy use ? say being discharged and charged once a week from april through October?i thought getting 3 years out of them was pretty decent but maybe if I charge them at higher amps they will last longer.

slonezp reply :

Other things to consider and if they were touched on I apologize for reposting. This applies to everyone but especially those who are not able to keep the boat plugged in 24/7. Charge up the batteries after your fishing trip. Don't wait until the night before your next fishing trip. Fully charge the batteries and top off the cells before storing the boat for the winter. Removing the batteries during the winter is a good practice but not necessary providing the batteries are fully charged and there is no parasitic drain on them. (Most of the newer computer controlled outboards will draw power from the starting battery 24/7 as will some of the electric steer trolling motors, and shallow water anchors). A battery cut off switch is a good idea.

@padon I change batteries every 5 years whether they need it or not. I don't think 5 years is an unreasonable life expectancy for a properly cared for battery. Some guys get more, I don't want to chance it.

Quarry Man reply :

it will work, but not for long. trade that in and get a walmart battery for under 100$

Largemouth21 reply :

On 8/23/2017 at 10:04 PM, slonezp said:

Other things to consider and if they were touched on I apologize for reposting. This applies to everyone but especially those who are not able to keep the boat plugged in 24/7. Charge up the batteries after your fishing trip. Don't wait until the night before your next fishing trip. Fully charge the batteries and top off the cells before storing the boat for the winter. Removing the batteries during the winter is a good practice but not necessary providing the batteries are fully charged and there is no parasitic drain on them. (Most of the newer computer controlled outboards will draw power from the starting battery 24/7 as will some of the electric steer trolling motors, and shallow water anchors). A battery cut off switch is a good idea.

@padon I change batteries every 5 years whether they need it or not. I don't think 5 years is an unreasonable life expectancy for a properly cared for battery. Some guys get more, I don't want to chance it.

Since I have a canoe, I can take my battery out in the garage and charge when needed. During the winter should I keep it inside? I'm sure all battery's lose a bit of juice when just sitting by themselves (not hooked up/no load) Co I keep it plugged in outside? Northern MI is COLD!!

Way2slow reply :

All batteries self discharge, depending on the alloy used, some much faster than others. The cheaper batteries like Walmarts usually need to be topped off every four to six weeks. Some of the better batteries every six to twelve weeks. The main thing is never let a battery sit when it's only at 80-85%. At that level is when the plates start to sulfate and if allowed to get a heavy coat of sulfur crystal on them, you can pretty much start writing it off. Some of the modern chargers have a high frequency maintenance mode that will take light sulfation off and help prevent it from developing, but once it gets too heavy, caustic soda is about the only thing that's going to get it, and that ain't something you should even think about trying yourself.

Actually, if you do a little research, you will find sulfation is the cause of about 85% of dead batteries turned in.

So called reconditioned batteries are normally just used, dead batteries that has gone through the caustic soda process and new electrolyte added.

One other bit of gee wiz into. Always check that little date sticker on the battery. That's the year and month the battery was stocked in the store. If it's several months old, you may be buying a damaged battery right off the shelf. Also, unless stranded and it's critical, never buy batteries at the lake side marina or any place that does not have a regular turnover of batteries. That sticker is not the manufacturing date, that's a coded number hid on the battery, it's only the date that was delivered to that location. That's usually applies to most all battery retailers.

RPreeb reply :

On 8/23/2017 at 2:29 AM, Largemouth21 said:

*sigh* how much money will I have in this

A Battery Tender is what you should have. See this link to Amazon: Battery Tender

This is what I use to keep my deep cycle camper battery healthy during the winter and between camping trips.

IndianaOutdoors reply :

On 8/24/2017 at 12:10 AM, RPreeb said:

A Battery Tender is what you should have. See this link to Amazon: Battery Tender

This is what I use to keep my deep cycle camper battery healthy during the winter and between camping trips.

Again. You do not want a battery tender for recharging deep cycles. It's fine for maintaining charge during non use periods but that's it. The blue schumaker auto charger that has been linked here a couple times has an automatic float charge that will maintain a battery the same as that battery tender. It also has a 15amp charge cycle for regular recharging.

On 8/23/2017 at 10:50 PM, Largemouth21 said:

Since I have a canoe, I can take my battery out in the garage and charge when needed. During the winter should I keep it inside? I'm sure all battery's lose a bit of juice when just sitting by themselves (not hooked up/no load) Co I keep it plugged in outside? Northern MI is COLD!!

For maximum life of the battery you will want to keep it indoors at least above freezing.

RPreeb reply :

On 8/24/2017 at 1:32 AM, IndianaOutdoors said:

Again. You do not want a battery tender for recharging deep cycles. It's fine for maintaining charge during non use periods but that's it. The blue schumaker auto charger that has been linked here a couple times has an automatic float charge that will maintain a battery the same as that battery tender. It also has a 15amp charge cycle for regular recharging.

Up to you, but the Battery Tender (that's the brand) Plus is the most often recommended unit on the 3 RV forums I frequent. RV's use a wide variety of battery configurations, but all are deep cycle systems. It has been very effective for me.

NHBull reply :

@Way2slow thanks for going the extra mile here.

I didn't know what I didn't know.......It is also why I like the site.

Way2slow reply :

Thanks,

The Battery Tender is a maintainer, it's not a charger. I personally prefer the Battery Minder, it has a pot in it that you can adjust the float voltage and have about a 1/2 dozen of them. I have five vehicles for just me and my wife, plus lawn mowers, gas air compressor, gas welder and a coupe batteries for portable TMs. If it wasn't for the maintainers, I would have a full time job just keeping batteries topped off. Don't hold me to it but I think both companies have gone to making 10 amp chargers but I think they were well over $100. Which is still cheap because my stand alone chargers were two to four times that.

One word of advise, anything you use to maintain the batteries needs checked/adjusted for the battery. The ideal float voltage for most true deep cycle batteries is 13.17 VDC. Cranking batteries can be 13.2 to 13.3. AGM batteries should be 13.4 VDC. So many of the cheaper charger/maintainers I see can have a float voltage as high as 13.7 VDC. This will burn up and also make them loose lots of water while stored. I'm not going into brands but the one pictured above is one of the worst about having too high of a float voltage. So, what I'm saying, if you want to take care of your battery, a couple of days after it has been on the charger and has gone into the float mode (if your charger has a float mode) take a good DVM and check it for no more than 13.2 for TM batteries and 13.4 for AGM's and cranking batteries. If it's off, see if it's adjustable, or go looking for another charger/maintainer.

Also, not all good chargers use a float voltage, several top brands cycle the charger on at a certain point of discharge and off when fully charged.

Also the $7 things Harbor Freight sells are usually too low of voltage, I checked several of those and they are usually below 13 volts. I have modified several of those for the proper voltage, but then they usually burn out in a couple of months.

Way2slow reply :

Now, if I just knew 10% of what I know about boats, cars, electronics etc, about building the dam wood fired brick oven I'm knee deep in building. How many wood fired oven experts do we have. Another one of my brain fart ideas that started off thinking I could do it for a couple hundreds dollars. Ha, Ha, I just spent twice that much on stuff to build the stand it's going on.

RPreeb reply :

Quote

The Battery Tender Plus is a 1.25-amp battery charger designed to fully charge a battery and maintain it at proper storage voltage without the damaging effects caused by trickle chargers

Battery Tender at 1.25-amp will charge as fast or faster than any 3-amp charger available,

I've hooked up my trailer battery when it's down to 50% (11.9v), which is the farthest it's ever supposed to be drained, and it charges up fully without any attention.

Largemouth21 reply :

On 8/23/2017 at 11:50 PM, Way2slow said:

All batteries self discharge, depending on the alloy used, some much faster than others. The cheaper batteries like Walmarts usually need to be topped off every four to six weeks. Some of the better batteries every six to twelve weeks. The main thing is never let a battery sit when it's only at 80-85%. At that level is when the plates start to sulfate and if allowed to get a heavy coat of sulfur crystal on them, you can pretty much start writing it off. Some of the modern chargers have a high frequency maintenance mode that will take light sulfation off and help prevent it from developing, but once it gets too heavy, caustic soda is about the only thing that's going to get it, and that ain't something you should even think about trying yourself.

Actually, if you do a little research, you will find sulfation is the cause of about 85% of dead batteries turned in.

So called reconditioned batteries are normally just used, dead batteries that has gone through the caustic soda process and new electrolyte added.

One other bit of gee wiz into. Always check that little date sticker on the battery. That's the year and month the battery was stocked in the store. If it's several months old, you may be buying a damaged battery right off the shelf. Also, unless stranded and it's critical, never buy batteries at the lake side marina or any place that does not have a regular turnover of batteries. That sticker is not the manufacturing date, that's a coded number hid on the battery, it's only the date that was delivered to that location. That's usually applies to most all battery retailers.

Lots of good information here! I will keep this in mind and hopefully I can help someone else someday!

On 8/24/2017 at 1:49 AM, NHBull said:

@Way2slow thanks for going the extra mile here.

I didn't know what I didn't know.......It is also why I like the site.

x2!

On 8/24/2017 at 1:32 AM, IndianaOutdoors said:

Again. You do not want a battery tender for recharging deep cycles. It's fine for maintaining charge during non use periods but that's it. The blue schumaker auto charger that has been linked here a couple times has an automatic float charge that will maintain a battery the same as that battery tender. It also has a 15amp charge cycle for regular recharging.

For maximum life of the battery you will want to keep it indoors at least above freezing.

I will keep it in my basement then. There's a wood stove and dehumidifier down there so it shouldn't freeze and/or corrode

On 8/24/2017 at 3:14 AM, Way2slow said:

Now, if I just knew 10% of what I know about boats, cars, electronics etc, about building the dam wood fired brick oven I'm knee deep in building. How many wood fired oven experts do we have. Another one of my brain fart ideas that started off thinking I could do it for a couple hundreds dollars. Ha, Ha, I just spent twice that much on stuff to build the stand it's going on.

ovenresource.com

good luck with your project let us know how it goes.

Thanks for sharing your boat information with me I learned a lot about battery's and charging,

On 8/24/2017 at 2:45 AM, Way2slow said:

Thanks,

The Battery Tender is a maintainer, it's not a charger. I personally prefer the Battery Minder, it has a pot in it that you can adjust the float voltage and have about a 1/2 dozen of them. I have five vehicles for just me and my wife, plus lawn mowers, gas air compressor, gas welder and a coupe batteries for portable TMs. If it wasn't for the maintainers, I would have a full time job just keeping batteries topped off. Don't hold me to it but I think both companies have gone to making 10 amp chargers but I think they were well over $100. Which is still cheap because my stand alone chargers were two to four times that.

One word of advise, anything you use to maintain the batteries needs checked/adjusted for the battery. The ideal float voltage for most true deep cycle batteries is 13.17 VDC. Cranking batteries can be 13.2 to 13.3. AGM batteries should be 13.4 VDC. So many of the cheaper charger/maintainers I see can have a float voltage as high as 13.7 VDC. This will burn up and also make them loose lots of water while stored. I'm not going into brands but the one pictured above is one of the worst about having too high of a float voltage. So, what I'm saying, if you want to take care of your battery, a couple of days after it has been on the charger and has gone into the float mode (if your charger has a float mode) take a good DVM and check it for no more than 13.2 for TM batteries and 13.4 for AGM's and cranking batteries. If it's off, see if it's adjustable, or go looking for another charger/maintainer.

Also, not all good chargers use a float voltage, several top brands cycle the charger on at a certain point of discharge and off when fully charged.

Also the $7 things Harbor Freight sells are usually too low of voltage, I checked several of those and they are usually below 13 volts. I have modified several of those for the proper voltage, but then they usually burn out in a couple of months.

The blue 50$ Walmart charger that we were talking about earlier, will that work for float charging? If it's just one battery have, I don't mind hooking it up to the charger every 4 weeks, I can mark it on a calendar or something. This is a lot of good information, thank you for helping out a trolling motor beginner.

IndianaOutdoors reply :

Yessir it automatically goes into float mode after the battery is charged. If you read the literature on the charger I believe they call it maintain mode.

Way2slow reply :

Yes, it will work but I have seen several of them destroy batteries because the float/maintenance voltage was too high. My son learned first hand with one, even after I told him to be sure to check the float voltage after a coupe of days of being on it when he first bought it. He didn't and four months later his battery was junk. It was a Walmart battery so they gave him a new one for free, four months later it was junk again. He called and asked me what's going on with their batteries, and I asked if he checked the float voltage, "NO". Again they gave him another battery, after three days of it being on the charger he checked the float voltage, 13.9 VDC. 13.4 is the absolute max you want to run flooded cell batteries on a maintenance charge, I keep mine at the 13.17 VCD on the chargers I can adjust and never over 13.2 on any charger. He took the charger back and made them give him a new one, that one was 13.3, good enough. A lot of the plants I used to go in, the maintenance shops had those, and I found a number of them that were way too high. I'm not saying it's a bad charger, get a good one and them seem to work great, just check it and make sure you have a good one. I have two of their Ship & Shore (or something like that) that were my dads and they work great, but they are also a little more expensive than the shown.

Largemouth21 reply :

On 8/25/2017 at 12:19 AM, Way2slow said:

Yes, it will work but I have seen several of them destroy batteries because the float/maintenance voltage was too high. My son learned first hand with one, even after I told him to be sure to check the float voltage after a coupe of days of being on it when he first bought it. He didn't and four months later his battery was junk. It was a Walmart battery so they gave him a new one for free, four months later it was junk again. He called and asked me what's going on with their batteries, and I asked if he checked the float voltage, "NO". Again they gave him another battery, after three days of it being on the charger he checked the float voltage, 13.9 VDC. 13.4 is the absolute max you want to run flooded cell batteries on a maintenance charge, I keep mine at the 13.17 VCD on the chargers I can adjust and never over 13.2 on any charger. He took the charger back and made them give him a new one, that one was 13.3, good enough. A lot of the plants I used to go in, the maintenance shops had those, and I found a number of them that were way too high. I'm not saying it's a bad charger, get a good one and them seem to work great, just check it and make sure you have a good one. I have two of their Ship & Shore (or something like that) that were my dads and they work great, but they are also a little more expensive than the shown.

okay, I'm not exactly sure how to check the voltage. Would it be hard on the battery to just top it off every once and a while? I'm not sure if the charger can be adjusted but it does say Ship and Shore on it.

EDIT: the box says it mantains at 3 AMPS not sure how that translates to volts

Bass_Fishing_Socal reply :

Very good info here, thanks everyone especially @Way2slow.

i also have that blue charger posted in this thread. I normally charge same day after using the boat, the battery only used for trolling motor, Fish finder. The battery is 12v deep circle marine battery.

I'm not sure if this the right way to charge battery if anyone could tell me or direct me to the right way. I set the amp to 15amp, the cell automatic to std. I don't leave charger on all the time. If the boat been parked for too long(winter months), I will top off the night before trip. When do I need 3amp mode? should I change to gel cell or leave it at std cell? Thanks in advance.

Way2slow reply :

To check the maintenance voltage, leave the charger on the battery and wait at least 24 hours after it has gone in the maintenance mode. When the battery charger first goes into the maintenance mode, the residual voltage of the battery is going to be too high to accurately check it. That's why I say wait two or three days. Then all you do is use a DVM and read the voltage across the two terminals while the charger is on and in the maintenance mode. I should not by any higher than 13.4VDC

Use the charger in the Automatic mode if leaving it on the battery. Actually, leave it there all the time, just in case you forget to disconnect it when done if you don't want to use the maintenance mode.

If you don't won't to use the maintenance mode that's fine. It's safer not to on many chargers anyway. Every six to eight weeks, connect the charger to the battery in automatic and leave it for a couple of hours. Take it back off when it shows it has gone into the maintenance mode.

Just don't forget to top it off at least every couple of months

Largemouth21 reply :

On 8/25/2017 at 8:01 AM, JustJames said:

Very good info here, thanks everyone especially @Way2slow.

Very true, I learned a lot. There are good people on here.

XpressJeff reply :

On 8/23/2017 at 4:02 AM, fishnkamp said:

I ran an all electric boat for reservoir fishing and on that boat were 5 deep cycles. One supplied a 12 volt trolling motor on the front deck. Then there were 4 more batteries feeding two transom mount 12 volt trolling motors. Each transom mount motor was a Minn Kota 55 pound thrust unit and it was fed by two batteries hooked up together. I use a total of 3 of these chargers and they did a terrific job. Wal Mart sells them for $45. All you need is one and use it every time you return home from fishing. Your batteries will last a long time.

https://www.walmart.com/ip/Schumacher-SpeedCharge-15-Amp-Automotive-and-Marine-Battery-Charger/13005745

THESE ARE GREAT! Will meet ALL your charging needs.

Johnbt reply :

I've been using 3 of the plastic Schumacher smart chargers for going on 4 years and my 3 Group 29DC Walmart batteries are holding up just fine. They're like new according to various meters. My chargers are the 2/6/10 variety and I use the 2 amp setting.

Other folks I fish with have used the 2 amp setting for a lot longer than I have and they're getting 5 or 6 years out of their $99 Walmart batteries.

Call us idiots, go ahead. I can deal with it. Maybe my smart charger is smarter than yours.

John

riverbasser reply :

Ok @Way2slow if your slow I don't know what I should be called lol. To make sure I'm comprehending everything, we want a 10-15 amp smart charger with automatic/float maintenance mode that once in this mode delivers no more than 13.2v and is preferably adjustable?

If I got all that right do you have any brands to reccomend for us? Thanks again

Choporoz reply :

Great stuff, @Way2slow. Thank you much for taking the time.

This thread (or at least W2S's posts) might/should be pinned.

I've been using a NOCO Genius 7.2A charger (from Amazon) with good results. I recently 'acquired' a newish Schumacher like the one pictured earlier in this thread. Both seem to satisfy my requirements (3 size 27 Interstate batteries - TM use only.) Best I can tell...and after I test the maintenance voltage....I can safely use these chargers for charging and for winter 'maintenance'.

New question. For my yak sonar, I use 12V 9Ah sealed lead acid (SLA) batteries. My first purchase of these came with a charger that was simply a block that plugged in and had two small gauge wires/clips. Not so much as a single indicator light. Instructions said to charge batteries for 24hrs...not much less....and be careful not much more. That worked very well for a couple years. This past spring, I had the bright idea to use my NOCO charger instead...because, well....they're 12V batteries...and it is a genius charger, right? One battery was shot in a couple months...maybe it was just old and at the end of its life...IDK. So...my question is:

-Can/should I use the NOCO and/or Genius to charge 9Ah SLA batteries? Better to just use the cheap cord charger that came with?

Hez reply :

The maintenance voltage on my Battery Tenders are 13.1 across the board. They charge at 13.6