Adding Water to Batteries

What is the general rule of thumb? I once read about when to add water to batteries - something about either before or after the charging process. I can't remember what the rule was. Anyone recall when the "right" time is to water the batteries as it relates to the charging cycle. For example, is it better to water after the batteries have experienced a draw such as being on the hook all weekend, or is it better to water them before we leave the dock when they are fully charged? Or, does it really not matter in our boats? :)

The amount of water in the batteries doesn't matter AS LONG as the water is above the top of the plates. Typically, periodic checking - say monthly - is fine and adding water whenever is perfectly OK.

If you do EQ charges, and you should every few months. the level should be checked before and after the EQ since it tends to boil off some water.

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Originally Posted by MikeP

The amount of water in the batteries doesn't matter AS LONG as the water is above the top of the plates. Typically, periodic checking - say monthly - is fine and adding water whenever is perfectly OK.

If you do EQ charges, and you should every few months. the level should be checked before and after the EQ since it tends to boil off some water.

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Mike what do you mean by EQ?

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Originally Posted by rsmith

Mike what do you mean by EQ?

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Equalization charge which raises the voltage for a short time to descale the plates.

The right time to add water to batteries is, when ever they are low.

JM

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Originally Posted by SKYCHENEY

Equalization charge which raises the voltage for a short time to descale the plates.

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???????...OK...can you put that in "blonde" terms? I still don't understand...but then again, as Pascal can attest...I'm electrically challenged when it comes to DC systems. :) Pascal can also tell you...when he tries to explain DC stuff to me, my eyes just glaze over, and then he gives up, but there is hope...I used to be like that for many, many years with football - I was in my mid 30s before I "got it", and look at the college football junkie I am now!! LOL

Is there something I'm supposed to be doing every so often as MikeP mentioned, which I'm probably not doing? I feel like I'm missing something, here.

just check them every month and add distilled water if they are low.

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Originally Posted by Angela

???????...OK...can you put that in "blonde" terms?

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OK, in "Blonde" terms...

When the battery is working, little bits of stuff (scale) collect on the plates as DC power is used.

After a while, enough stuff has collected on the plates that the battery can not produce power.

When you charge the battery, it reverses the process and the stuff sheds off the plates. Charging the battery also causes the liquid to bubble a bit and if left unchecked, this could lower the liquid level to the point the plates are exposed which will damage them. So the answer to your first question is to top off batteries BEFORE charging.

Most chargers today are smart in that they will adjust the charge rate proportional to how much the battery needs. You can leave a smart charger on for extended time. (I always turn off the charger before starting the engines to avoid a power surge)

The equalization charge is a low power charge designed to keep the plates scale free and batteries in peak condition.

So, go to Walmart and pick up a gallon of distilled water to keep in the ER. Use this to top off the battery banks every 2-4 weeks.

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.

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"

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.

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.

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.

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.

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.

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?

Funny, even with religious watering, which is absolutely needed every three weeks, my Sentry and 819 combo has a 3 year battery replacement cycle, for both me and the PO. I have used my boat a lot, so I just chalked it up the combo of a crappy charger and heavy use. A good charger costs as much as new batteries, or more, so I haven't got around to "doing the right thing".

The Sentry is apparently performing within specs, I checked it using advice from Steve, "spcoolin". It just seems incapable of charging two different banks with two different usage profiles. Starboard bank, which always dies first, is start only for the main engine, plus feeds the 12 point monitoring system. Port is house bank and port starter.

I think I may go to two separate chargers for each bank, or float testing the Sentry and trying an Analytic. Float testing the Sentry would have great psychological rewards as well.

I have not added water all year either. The Rolls with the Outback charger have not needed a drop. This the first time that has happened, but this is the first year I have used the Outback as a charger. I called Rolls and programmed the charger to their specs. What a difference.

BTW, we anchored out quite a bit in the North Channel this summer and put over 1000nm on her, so it's not like she just sat at the dock with the charger on.

Back to the battery question: I agree that I would not replace at 3 years. I put 5 years on my Interstate 8v195's before they had to come out.

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Originally Posted by SKYCHENEY

Equalization charge which raises the voltage for a short time to descale the plates.

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Some charger units, e.g. in the Heart Inverter/Charger have a software driven "equalization cycle". That cycle, when engaged, puts a high voltage charge on the batts at a declining voltage value over an 8 hour period. It serves to boil up the deposits on the bottom of the batt and re-deposit them on the plates, thereby increasing the life of the battery; also lessening the chance of a short in one cell of the plates the bottom of the battery.

My understanding...

"It serves to boil up the deposits on the bottom of the batt and re-deposit them on the plates, thereby increasing the life of the battery.."

Not so..once accumulated particles, crystals, fall from the plates they cannot be dissolved and the battery is weakened permanently. Equalization CAN reverse RECENT (soft) particle accumulation on battery plates, but even crud that has been on plates for weeks and become hardened crystals is lost permanently. When accumulated crud reaches the bottom of plates, they are shorted and the battery is a goner.

That's why all battery manufacturers recommend prompt recharge after battery use. Daily recharge is, according to battery manufactruers, best for the life of the batteries.

Is that the same as desulfation?

Thanks for all the input. It is relatively easy to get 12V batteries in places like Cabo, Puerto Vallarta and Manzanillo. We are within cab distance in these places. But I bet (don't know for sure) that 8V batteries are hard to come by. They are readily available here in San Diego, so perhaps I might change out the one bank just to be proactive. Ross

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Originally Posted by 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.

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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.

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Originally Posted by Pascal

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.

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I think Ross's use is far more critical than most. A few months in waters where you have hundreds of miles to the next port and there are not many parts available makes changing them before they fail a good move.

How many people change their oil more often than the recommended intervals?

How many people fill up at half a tank just in case?

If he were to have a battery failure on the trip it could be serious. I would probably carry a spare 8v195 along with all my other emergency supplies but then again who am I to say what he needs :)

Ross enjoy the trip. It sounds like a great trip of a lifetime and I am jealous that you are doing it "again". If you need a deckhand ....

It's a wise man that is proactive in avoiding problems. The price of a new set of batteries pales in comparison to the problems than can result in their failure. Have a safe and great trip Ross, and don't worry about leaving the light on.

Thanks you guys. Just an update...My four new 8V batteries are being delivered next week, so the 3 yr. old bank will be new and the stbd. bank (starting bank) will be 2yrs. old this Nov. So we should be good to go. Now if my back will hold up pulling the old ones out and putting the new ones in, I'll be a happy camper. Ross