Battery acid stains

[Scotto97]

Last year I overfilled my batteries and they leaked onto the bilge gelcoat leaving light brown stains

Anyone ideas on removing the stains?

It doesn't appear the gelcoat has been burned or damaged, just stained

Thanks

 

[ziekman@cox.net]

I have the same issue - believe me it will never happen again.

 

[Bt Doctur]

Batteries should not normally need water added . most issues arise from overcharging, this will boil out the water.
Biggest culprit is the onboard charger when hooked to shore power, second is a run-away alt. Nominal voltage should be 14.3- 14.6 when underway. GOOD engine batteries should not need a charge weekend to weekend. By constantly having the shore power charger on all the time you can mask a battery going dead. Trouble is you wont find this out untill your anchored up and go to start your motors.The batteries are dead. Do you have to plug you car in every night, NO. Go on vacation for a month, is the car battery dead, NO. So why does you boat need the engine batteries always charged?
They don`t. You want engine starting batteries for the engines ONLY. Install house batteries for your 12V stuff and run the battery charger to them, not the engines. Besides, once the battery plates are exposed, capacity goes out the window.
If you really want this type of system, invest in SeaTow or it`s equivalent. You will have dead batteries.
For spilled acid, clean with baking soda and water, stains will need to be painted over.

 

[powdajohn]

Hey Bt Doctur,
Can't thank you enough for the high content information.

 

[Nehalennia]

BT DR. is not considering that boats are left for weeks at a time, not driven daily as our cars/trucks are. Our vehicles are also not as taxed as the systems on our vessels are and pulling a draw from many sources. Yes in a simpler boat with less systems: I.E. Engine, stereo and bilge pump you can get away with treating like a car/truck. In a vessel with interior lights, fridge, water pump, vacuflush, stereo, oooh another fridge, TV, inverter, etc, there is not a way for a battery bank to recover from the draw within a normal run on the alternator back to your mooring. This recovery requires a proper battery charger. Anyway I'm not answering your question regarding stains, but neither is the Bt Dr with his misinformation. His only statement that I see is correct is regarding that batteries 'should not normally need water added '. Periodically yes if they are flooded acid. AGM, no.
I get where he's coming from but it's a blanket statement that doesn't account for proper, modern chargers and systems. His comments have nothing to do with your overfilling your batteries. Best of luck.

 

[Lazy Daze]

I agree with Todd that the best thing you can do for your batteries (for longevity) is to keep them on a maintenance/conditioner charger all the time. Your OEM onboard charger is designed for that.

For cleaning it... I've only ever seen acid stains as a whitish color - unless maybe the acid combined with dirt/grime/oil/whatever that is already on the bilge. But, you could try any number of things: Simple Green, 409, Fantastik, Mineral Spirits, Acetone, etc. It's dry now, so you can safely try anything. Heck, you could even use more battery acid. Of course, then be sure to neutralize the area with a little baking soda/water.