What should DC battery ready 1-2 weeks between charging? What about starting?

[dmc575]

So I think i have bad batteries.....and I have a feeling its the boat and not the battery since my last set of batteries lasted me 13 and 14 months. Just out of the damn warranty period!

So far no problems on the water, but I just checked the volts and one of my batteries read at 12.5 and the other at 12.4. I dont keep them hooked up all the time, and pretty much charge them for a day after fishing trips...or if its been awhile since I go fishing I hook them up to the charger every couple weeks or so...may have gone longer, about 3 weeks once before. but its been about every 2 weeks give or take a few days when I plug the DC batteries up to charge.

The last time I plugged in was about a week ago, and I just plugged in to top off for upcoming fishing trip (like I always do as well). Before I did though the batteries read at 12.4 and 12.5...which isnt the worse but for just sitting out in the sun i figure theyd be higher. Or is that normal? Im planning to test a couple hours after I unplug before the trip to see where theyre at, and I believe that should be 12.6 or 12.7.....right? Im using a MK 210 2 bank charger thats only about a year and half old (https://www.walmart.com/ip/Minn-Kota...SABEgKmxfD_BwE).

Also...my starting battery was reading 12.2 and it was plugged in about a week ago too. this battery (walmart brand) is only 3 or 4 months old so Im wondering whats going on...because this battery is now doing what the last one was doing and it looks like it doesnt take a full charge with my charger. Im using a noco genius .75 amp charger (https://www.autozone.com/test-scan-a...ger/388458_0_0), and it flashes red while charging and green for fully charged. When I got the battery at first it would go green on me....now it just stays red like its continually charging, which is what another of these batteries did to me and I returned. Kinda worried that it read 12.2 just now when I keep that in mind.

What do you all think is going on...or am i just overreacting?

[CatFan]

You can’t really tell unless you unhook everything but the charger whether it is batteries or something else. Readings as soon as you unplug the charger will be over 13V.

I wouldn’t count on a 750mA charger to keep your cranking battery charged. There is a constant draw from the outboard it will have to fight.

[bobcoy]

Your batteries need to be charged to 100% after each use. Not a week or 2 later. For the time the battery stays less than 100% your batteries are loosing capacity. Maybe use a charger that will maintain them properly at full charge all the time.

[dmc575]

Your batteries need to be charged to 100% after each use. Not a week or 2 later. For the time the battery stays less than 100% your batteries are loosing capacity. Maybe use a charger that will maintain them properly at full charge all the time.

I do charge them after each use.

Before I go fishing (usually every week or 2 on its own except summer), I plug in to top off my batteries. Go fish. I get home, unhook the boat and plug in the charger for both batteries. So theyre plugged in within 3 hours of getting off the water and I usually leave it plugged in for a couple days or so and unplug it. Then repeat...unless I havent fished in a while. So if I havent fished for a while, 2 weeks or so AFTER charging it after a day on the water and getting home, then ill replug them in to top them off since ive been told and read that its better to keep these as close to topped off as possible instead of letting them stay discharged.

Never charged my starting battery before and didnt have any problems for a year but it gave out on me just after the warranty. Talked to a buddy and he told me to charge that one up to after using it, so now I charge the starting battery too. been doing that for a few months. Thats the one im really worried about...

You can’t really tell unless you unhook everything but the charger whether it is batteries or something else. Readings as soon as you unplug the charger will be over 13V.

I wouldn’t count on a 750mA charger to keep your cranking battery charged. There is a constant draw from the outboard it will have to fight.

So i should get a bigger charger for it? what is the minimum I can get away with to do it right? I hate buying batteries every year so wanna do all i can to get max life out of them.

[Rip Bass]

I wouldn’t use any less than a 10 A charger for a wet cell battery. Are you keeping a check on the fluid in the batteries? It does evaporate after a while.

[dmc575]

I wouldn’t use any less than a 10 A charger for a wet cell battery. Are you keeping a check on the fluid in the batteries? It does evaporate after a while.

Prolly not as often as I should but yes. Havent filled them tho....where should they be filled to?

[CatFan]

I do charge them after each use.

Before I go fishing (usually every week or 2 on its own except summer), I plug in to top off my batteries. Go fish. I get home, unhook the boat and plug in the charger for both batteries. So theyre plugged in within 3 hours of getting off the water and I usually leave it plugged in for a couple days or so and unplug it. Then repeat...unless I havent fished in a while. So if I havent fished for a while, 2 weeks or so AFTER charging it after a day on the water and getting home, then ill replug them in to top them off since ive been told and read that its better to keep these as close to topped off as possible instead of letting them stay discharged.

Never charged my starting battery before and didnt have any problems for a year but it gave out on me just after the warranty. Talked to a buddy and he told me to charge that one up to after using it, so now I charge the starting battery too. been doing that for a few months. Thats the one im really worried about...




So i should get a bigger charger for it? what is the minimum I can get away with to do it right? I hate buying batteries every year so wanna do all i can to get max life out of them.

5A should bo okay for that starting battery.

[dmc575]

5A should bo okay for that starting battery.

https://www.amazon.com/STANLEY-BC8S-...%2C170&sr=8-14

will that work?

[bobcoy]

Sounds like you are doing everything right except keeping up with the watering. Bob

[billnorman1]

Prolly not as often as I should but yes. Havent filled them tho....where should they be filled to?

Shine a flashlight into the battery after charging. If you can see electrolyte it is probably full. If you can see tops of the plates above the electrolyte, it ain't. 3/8" over the plates is the formal amount.

[CatFan]

https://www.amazon.com/STANLEY-BC8S-...%2C170&sr=8-14

will that work?

Should do it

[dmc575]

Should do it

That was the cheapest one. This one seems like pretty good bang for your buck and has a reader on it.

https://www.amazon.com/gp/product/B0...P047W6G0&psc=1

I went cheap on the last one. $40 is still cheap for all we spend, but figure its worth the extra few bucks cuz it looks better. has good reviews too.

[jawjatek]

As noted above: I have that same little NOCO G750 charger (I use mine to charge a small 9Ah - 12Ah batteries), and it is rated for 30 Ah batteries max, so there is no way can it handle the batteries you are trying to charge with it.

[wmitch2]

Just my humble opinion, but your using "Toys" to do the job when you need a "Real" charger. The MK is ok for the two batteries, if it is working correctly, I assume you have them on the Trolling Motor batteries, but I'm guessing here. And then you want to charge a starting battery with a Stanley charger. First go have your batteries tested anywhere they can give you a PRINTOUT of the condition. (Sam's CLub for one). THEN if they test good, hook your charger up to them one way, note the lights, then switch the leads and see if the lights show the same. Also, check them as they are charging with a good Volt/Ohm meter, you should read between 13.25-14 volts. Under 13, the charger is on it's last legs. IF I WERE YOU, I'd get 1 ON-BOARD charger that will charge ALL of your batteries, be it 1,2 or 3 OR 4 !! Like I said JMHO !!

[dmc575]

Just my humble opinion, but your using "Toys" to do the job when you need a "Real" charger. The MK is ok for the two batteries, if it is working correctly, I assume you have them on the Trolling Motor batteries, but I'm guessing here. And then you want to charge a starting battery with a Stanley charger. First go have your batteries tested anywhere they can give you a PRINTOUT of the condition. (Sam's CLub for one). THEN if they test good, hook your charger up to them one way, note the lights, then switch the leads and see if the lights show the same. Also, check them as they are charging with a good Volt/Ohm meter, you should read between 13.25-14 volts. Under 13, the charger is on it's last legs. IF I WERE YOU, I'd get 1 ON-BOARD charger that will charge ALL of your batteries, be it 1,2 or 3 OR 4 !! Like I said JMHO !!

My batteries are in 2 seperate parts of my boat. My TM batteries are wired directly to the TM and in my rod lockers at the deck. My cranking battery is in the back. not really a doable option.

since you consider the chargers I posted toy chargers...can you link me one that will take care of the job and not charge me an arm and leg for?

[dmc575]

going fishing tuesday and plugging in batteries tomorrow....ill post what they ready while charging.

[wmitch2]

My batteries are in 2 seperate parts of my boat. My TM batteries are wired directly to the TM and in my rod lockers at the deck. My cranking battery is in the back. not really a doable option.

since you consider the chargers I posted toy chargers...can you link me one that will take care of the job and not charge me an arm and leg for?

For the Trolling Motors alone

https://www.wholesalemarine.com/dual...2-bank-20-amp/

For the Starting Motor

https://www.wholesalemarine.com/dual...1-bank-10-amp/

And if you can mount it in the middle and wire it both ways,,

https://www.wholesalemarine.com/dual...3-bank-30-amp/