Adding Water to Batteries

[REBrueckner]

Adding distilled water periodically and NEVER letting plate tops become exposed is appropriate. Keep in mind that when you add water the electrolyte solution will have an uneven mixture...water on top and electrolyte below....so in general adding water before or during charging when dockside is a good time because the charging bubbles will help mix the electrolyte solution.

Equalizing depends on how much the batteries are used. If you deep cycle batteries continuously as when cruising and hanging on the hook, more frequent equalization is recommended. But I was never able to get any rules of thumb from several battery manufacturers....but charger makers provide that capability so either it's a real benefit or a marketing/ competitive gimmick...I still don't know which.

I do know that spring and fall equalizing of my 8D's, usually for about 8 to 12 hours, with six mos full time cruising and cycling from May thru October and mostly winter idle time during the cold weather did NOT make any discernable difference in battery life. I got about five years before the twice annual equalization and the same after...consistently one cell or ocassionaly two would become weak within a battery or two and that's when I had to replace the bank....several times if one battery cell became virtually weak or dead and I replaced that battery alone, then the other batteries of equal age and use would fail within six mos or less....so I developed the preventative measure of changing all batts in a bank when one failed at at about five years. I still don't know why one cell fails so often before others.

I used Power Master, Exide, and Interstate 12v Deep Cycle with about equal results as far as I could tell. Usually as charge time to get to about 85% of full charge during cruising became longer, I'd check and find that bank at 4 to five years of age and consistently during the following winter a cell or two would weaken and I'd replace the bank the following spring before departure. I rotated 3 bank replacement times so I always had one bank aboard that was only one or two years old.

[Pascal]

i dont think your charger has an equalization mode... otherwise one a year is usually fine. you need to check water before and after and make sure it's all well ventilated (caps and battery box covers off)

i really dont' think when you top off the batteries matter, at least out in the real world. I'm sure someone will find a white paper somewhere which will argue why one way of another is best...

"just do it"

[Dustoff44]

I have a Flo-rite system to water my batteries ( 3 banks 8v Deep Cycle ) from one location. Flo-rite recommends adding water on a fully charged battery because you will lose some water during the charging cycle. Topping off water prior to charging and not after you might lose enough water during the charge cycle to be a problem.

In Actuality I top off water each time I open my generator compartment door.
I cycle which bank is used as the house bank and normally the last bank used will take a little water. A lot in the summer not so much in the winter.

[31FlyCruzr]

My 2 cts, it matters how far you have discharged and what is doing the re-charge.

A consta-volt Trickle charge doesn't boil out water for the most part.

Running batteries down on the hook, is likely followed by engine alternator (think high amperage) quick charge for a fair period of time to get the battery back up, this is when I'd expect your greatest opportunity for boil off of water will occur.

My take, check after re-charging "on the hook" events in addition to a regular periodic check.

Pre-charging water check is usually for a dead battery, when lack of water may be the problem. Good practice anytime you are using a portable charger.

[sgharford]

Add yet another 2 cents - Last year I upgraded alternators (from 55 amp to 160 amp) and added Balmar multistage voltage regulators with remote temperature sensors on both alternator and batteries that will tamp down juice if it senses overheating on either. Prior voltage regulator was just on/off type and required I added water about 6-8 weeks. This season I haven't had to add any water - All 4 rolls's 8-D's are almost exactly where I left them at last fill up last year. Pretty nifty as they are PIA to get at. Believe the hype about multi-stage regulators - great upgrade you can make to your charging system.

[Ross Macdonald]

Kind of a related question. We are getting ready for another long trip to Mexico and batteries are always an issue. Conventional wisdom (I think) is standard (not rolls) wet cell, lead-acid batteries should be changed out every three years no matter what. My starting bank is just short of 3 yrs old, and the house bank is 2 yrs. old. The inverter system is independent of the other batteries. So the 8 volt house and start batteries don't get drawn down much except for head use and starting the mains. Two months on the hook this summer and they seemed to hold a charge well. Any thoughts? Even though the banks are right down the center of the engine room, it's still alot of heavy lifting for an old guy. Thanks, Ross 60 EB.

[MikeP]

We anchor out a good bit and our "normal" (non Rolls) batts lasted almost 7 years before they needed replacing. Personally, I would not consider replacing batts at 3 years as an "automatic" thing. I would replace them when they began exhibiting behavior that showed the need for it. That should be considerable time before actual failure.

[rsmith]

I used to get 5-7 years out of a set when I had the old Sentry charger now I get 3 with my new Charles ferro charger. If you have the ability to parallel start I would do the oldest set. I did see a guy get his 12's started in the Bahamas with 3 large 12v car batts in series. Can you buy them in mexico if they drop dead on you?

[Pascal]

Kind of a related question. We are getting ready for another long trip to Mexico and batteries are always an issue. Conventional wisdom (I think) is standard (not rolls) wet cell, lead-acid batteries should be changed out every three years no matter what. My starting bank is just short of 3 yrs old, and the house bank is 2 yrs. old. The inverter system is independent of the other batteries. So the 8 volt house and start batteries don't get drawn down much except for head use and starting the mains. Two months on the hook this summer and they seemed to hold a charge well. Any thoughts? Even though the banks are right down the center of the engine room, it's still alot of heavy lifting for an old guy. Thanks, Ross 60 EB.

three years for lead acids would be very short unless the batteries have been abused by a bad charger, not adding enough water or deep discharge.

on small boats, the DC fridge and DC lights have a big impact on small banks but it's not the case on larger boats where a lot of the DC loads are shifted to AC when you have an inverter bank.

i get 5 years out of my "unfit for hatteras service" golf cart batteries, i cant' imagine 8Ds lasting less than that.

the two banks give you redundancy increased even further by having a dedicated inverter bank. you should be good for another couple of years, at least.