Battery update

john in la · Jan 28, 2020

Well after filling the battery with water I put it on a 10 amp charger. When I disconnect the charger the battery had 12.7 volts. I let it sit over night and it has 12.2 volts this morning. Looks like I may have got lucky. I will now hook it to a camper charger that has a cycle that is suppose to for lack of a better term clean up the battery.

What I do not understand is this boat has 3 batteries. One cranking and two deep cycle. Both deep cycle batteries are hooked to the same two phase charger but this one battery is the only one that was low on water. Both other batteries are showing 12.4 volts and are full of water.

Janicholson · Jan 28, 2020

A sulphated cell will cause over charging on the other cells in that battery, and heat/loose electrolyte in itself. Loosing down to 12.2 is the sign. Jim

Steve@Advance · Jan 28, 2020

If there is a small load on that battery it will cause the electrolyte to evaporate away.

Connect a test light in series with the final connection, see if there is a drain.

Mark-Ia · Jan 28, 2020

Have it load tested at a parts store and see if it's any good.

timcasbolt · Jan 28, 2020

(quoted from post at 10:52:37 01/28/20) Well after filling the battery with water I put it on a 10 amp charger. When I disconnect the charger the battery had 12.7 volts. I let it sit over night and it has 12.2 volts this morning. Looks like I may have got lucky. I will now hook it to a camper charger that has a cycle that is suppose to for lack of a better term clean up the battery.

What I do not understand is this boat has 3 batteries. One cranking and two deep cycle. Both deep cycle batteries are hooked to the same two phase charger but this one battery is the only one that was low on water. Both other batteries are showing 12.4 volts and are full of water.

If the cranking battery is the only one getting recharged by the alternator, is there any chance the regulator is faulty?

David G · Jan 28, 2020

12.2 is not a good battery.

ErnieD · Jan 28, 2020

Two 12's in parallel is not a good combination. If you have the remotest idea one cell is shorted it is a disaster waiting to happen. I STRONGLY recommend ditching both batteries and going for a 4D or 8D or two sixes in series. Batteries have an internal resistance and when that difference is in series one will self discharge the other. They will not take up the load evenly or charge evenly.

I took out a solid state battery combiner on my motorhome with 2x12 in series, one with a dead cell. The alternator saw no load and ran away. The dash air was on high, taking 30+volts from the alternator. Blue smoke out of the dash vents, no place to pull off in bumper to bumper multilane traffic. Thought we were on fire.

Batteries in parallel can blow up or thermal run away. Look in the John Deere tractor forum for 3020/4020 insight if you need more information.

john in la · Jan 28, 2020

The batteries are Not hooked in parallel or series. There is a switch so I can choose battery 1 or battery 2 but not both at the same time. They only run a 12 volt trailing motor only. All the lights and dash are run by the cranking battery.

john in la · Jan 28, 2020

Thanks guys. I?m going to put it on the RV charger and let it run threw the de-sulphate cycle. I really got nothing to lose giving it a try.

jeffcat · Jan 28, 2020

This one from Harbor Freight does everything automatically. Desulfate mode and temperature compensated. I now have four of them and the two in use have been dandy! Other folks on here love them too. They go on special every few months for $24.oo.

Blackhole49 · Jan 29, 2020

Don't be afraid to try the peroxide. I promise it works and definitely can't hurt.

Battery update

john in la

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Janicholson

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Steve@Advance

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Mark-Ia

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timcasbolt

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David G

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ErnieD

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john in la

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john in la

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jeffcat

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Blackhole49

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