Battery Care and Maintenance

[OlJarhead]

I am not sure we have a thread specific to this title anywhere and I've been thinking about asking a few questions and just noticed others have too.....perhaps a moderator could assemble them all in here?  I think it would be great to have such a thread.

So to start off:  I am no battery expert at all and frankly, while I've worked with them in Telecom for a long time now I still don't really spend enough time learning about them to know the answers.  On the other hand I do know one thing:  ask here

I have 8 220AH GCB's and the Trojan Battery Company (that makes a lot of these so I think they may be theirs -- I got them at Costco) tells me to Equalize at 15.50vdc -- which seems very high to me but I don't know squat in that department so have to take the manufacturers word for it -- and while it kinda scares me to do that I'm slowly convincing myself that overcharging them for an hour (just an hour right?) is the right thing to do.  However I have some questions:

1.  Should I remove the caps while equalizing?  I can't, of course, if I am not there but when there is there any reason to do this?  Not to do this?
2.  During Equalize I realize the batteries will boil and may exhaust acid to the tops of the batteries (I think anyway) -- what do you use to clean that up?  Baking powder?
3.  Since the batteries will gas during this boiling equalize process and since I don't yet have a fan set up to help get rid of the gases, is a window in my porch cracked 1" enough ventilation?  Or should I open them wide?  Install a vent, any vent, while waiting for the fan to arrive?
4.  Trojan says to equalize every 28 days -- I assume I just need to accept that I have to do this but then I can't run my inverter at the same time which means I can't run a freezer when I'm not there.  What is the risk of just letting the inverter shut down when it sees the over voltage?  How about not equalizing except whenever I am at the cabin?
5.  Glenn mentioned an additive and for the life of me I always forget where that darn post is    Can you post it here so it will always be available in a battery care and maintenance thread?
6.  Since batteries lose a lot of power (for lack of better phrase) in the cold does it help to wrap them in an insulating blanket?  Insulate the box itself?  Or just leave them in the porch which will be insulated and allow solar heating to keep them warm?

If I think of more I'll add them but for now I think these will greatly help me and I really appreciate the input and assistance from all of you!

Here is the link to Trojan:http://www.trojanbattery.com/BatteryMaintenance/Testing.aspx

[OlJarhead]

Many experts recommend that batteries be equalized periodically, ranging anywhere from once a month to once or twice per year. However, Trojan only recommends equalizing when low or wide ranging specific gravity (+/- .015) are detected after fully charging a battery.

Seems I had the frequency wrong here.

I need a hydrometer I guess....where can I get one?

[MountainDon]

Yes you do need a hydrometer.    NAPA is probably the easiest to find one at. Last I looked they have several models, one with a built in thermometer. Rinsing it with plain water after use makes the rubber last longer.  I have a nice one with small raised bumps on the float. That helps to keep the float from wanting to stick to the sides of the main tube. I got it from TheSolar.Biz years ago... don't know if they still sell it.

Yes, equalizing when necessary, because of variance between cell specific gravity OR once every six months "just because".


No need to take the caps off UNLESS one has the fancy 'Hydrocaps" which act to recombine the hydrogen and oxygen from normal use back into water.


I bring the batteries up to the equalization point and then hold them for an hour or so. Stop the process if the temperature rises above 125 F.  When sp gr readings taken a half hour apart are the same the batteries are equalized. I also check the water level again half way through the process and add if necessary. That gives time for the continued equalizing to mix it well.


I use plain water to wash off the batteries a couple of times a year. Plain clean water after I remove any dust with an old paint brush. I do NOT use any alkali substances as I have a fear of some/any of it getting into the acid. I DO keep a mixed solution and a box of baking soda handy just in case I do something stupid, or suffer bad luck, while around the batteries.


Insulating batteries in cold weather can help if there is a source of heat to conserve. If the batteries in question are being used daily it makes sense to have some insulation. The charging and discharging does create heat as a byproduct. If on the other hand the batteries sit most of the time through the winter without any use I don't see the point. That's my personal view. EG: our batteries sit for a week at this time of year between use. Later on in winter that turns into a two week period. In that time there is a small daily bulk/absorb/float cycle every day. Not enough to make any noticeable heat. Everything tries its hardest to reach some low temperature point. I covered the cold weather reduced capacity issue by installing a battery bank of greater than needed capacity.


I leave the battery box doors open while equalizing. Otherwise the doors are shut and the natural rising of the hydrogen vents any out two vents in the upper corners of the battery chamber pitched roof.


I've never had an explosion and I always check for hydrogen with a match every time I open the battery box door.      No I don't!!!   But I do know someone who lost most of the use of an eye because he stuck his head into a battery storage room with a lit cigarette in his mouth.


Equalizing voltages can harm some electrical equipment, such as inverters. Other DC equipment connected directly to the batteries could also be damaged by the higher than normal voltage. Best to check the ratings on all equipment beforehand.  An inverter/charger will pass the incoming AC power through to the cabin AC circuits, basically removing the batteries from the system during charging and equalization.  The maximum DC voltage of my inverter/charger is also high enough that it is safe while performing an equalization when using the Charge Controller to do the job with PV power. Although I must admit to pulling the inverter/charger offline when I do a sub powered equalization. 

[MountainDon]

Perhaps adding the SoC, State of Charge tables I presented in the Off Grid topic might be appropriate for here. These are temperature compensated tables.

12 Volt for flooded acid batteries




24 Volt for flooded acid batteries




48 Volt for flooded acid batteries




12 Volt for AGM batteries




24 Volt for AGM batteries




And a quick, non temperature corrected chart....

[NM_Shooter]

Here is an excellent tutorial page :

http://www.windsun.com/Batteries/Battery_FAQ.htm

[OlJarhead]

Thanks guys!

I'll be doing some reading and planning and will likely have more questions.  This weekend I couldn't pump any water because my batteries were dead on the well pump....seems something happened when we were gone and the charge controller tripped or something...the 24v bank was reading 2.4vdc!

[NM_Shooter]

Thanks guys!

I'll be doing some reading and planning and will likely have more questions.  This weekend I couldn't pump any water because my batteries were dead on the well pump....seems something happened when we were gone and the charge controller tripped or something...the 24v bank was reading 2.4vdc!

Oh no.... that's likely more than dead... that sounds damaged 

[OlJarhead]

Oh no.... that's likely more than dead... that sounds damaged 

Had two RV deep cycle batteries do this once before and I just ran them on the charger for a few days and they came back   Never have been as good as new mind you but still hold a charge for a while.

I think those two AGM's might also come back but we'll see.

[OlJarhead]

5.  Glenn mentioned an additive and for the life of me I always forget where that darn post is    Can you post it here so it will always be available in a battery care and maintenance thread?

I noticed this wasn't answered here (I came looking for the answer) and I appologize beasue I know Glenn's answered more then once elsewhere...so can you do it here so it's easy to find?

I'm in the process of possibly buying 4 used GCB's to increase my capacity over the winter and was thinking that it would be good to treat all 12 batteries to some TLC because abusing them too much.

[firefox]

I don't know if anyone has mentioned this before, but the military uses pulsetech solargizers in there vehicles to desulphate and maintain their batteries. They have all kinds of different types for various battery configurations.
I have one maintaining the 2 12volt batteries in my CUCV M1008 and I will attest that they do a good job. I don't have to replace batteries as quickly as I used to.
Essentially it sends a high voltage pulse thru the batteries periodically which keeps sulphate from building up on the plates. The sulphate buildup is the main reason for battery failure.
They probably have a more technical report at Pulsetech.

>>>>You may need to check how they interact with any electronics you are using with your system before hooking one up.<<<<

Bruce

[hpinson]

I'll add a bit about AGM (Absorption Glass Mat) deep cycle batteries.  Please point out errors and omissions and I'll add, edit and correct.

Deep cycle AGM batteries hold little liquid. Electrolyte is held in the glass mats. Since the batteries are sealed, evaporation of electrolyte is basically not a problem.

I'm using these in a buried-box outdoor well pump application, where temperatures can range from 50C down to -28C. If I had a heated structure to house the batteries, I would be using flooded lead-acid deep cycle instead. Charge for me is about 14V and float about 13V on a pleasant spring or fall day (see tables above).

Advantages of AGM are:

-- Low maintenance, in that you do not need to add water or monitor water levels

-- Freeze tolerance: ideal for outdoor applications where sub-freezing temperatures are encountered. Since there is no water to freeze, the batteries will not crack and leak in extreme cold weather and freeze/ thaw cycles. Freezing does not kill the electrolyte until something like -60F.

-- They accept a charge quickly, allowing the battery to work more and charge less.

-- Minimal hydrogen gas emissions. Venting needs are greatly reduced. Corrosion is not such a problem as with lead-acid.

-- Can be mounted in odd positions, since there is no liquid to leak out.

-- Vibration does not cause electrolyte to spill.

Disadvantages:

-- Cost is 1.5 to 2 time more than flooded lead-acid batteries.

-- They do not last as long as flooded lead-acid batteries.

-- Overcharging and overheating leads to premature loss of capacity or failure.

-- They require temperature monitoring by the charge controller to deliver optimal charge (most newer charge controllers support this with a specific AGM setting).


Rules of thumb:

-- Recharge to 100% after each discharge. Not always possible or practical I know! This is why these AGM batteries have a shorter life than lead-acid do.

-- Charge with a controller optimized for AGM. The controller should have a mechanism to measure remote temperature at the battery and deliver proper charge accordingly.  Prostar and Xantrex are companies that sell this sort of charge controller. It is usually a switch setting (Lead Acid / AGM / Gel).

-- Do not equalize.  AGM batteries when subjected to overcharging have no place to vent. The worst case is a fire or explosion.  Some battery manufacturers explicitly prohibit it. With other manufacturers, limited equalization is possible. Follow manufacturers recommendations closely-- some manufacturers have procedures for very limited equalization to help a failing AGM battery. See MountainDon's comment below.

[MountainDon]

--In general do not equalize. 

I would remove the "in general" phrase.  Make that never equalize AGM. Equalization involves higher than normal voltages that in my experience are guaranteed to produce off gassing. If the AGM's in question are having issues, replace them as soon as you can. Equalizing AGM will, IMO, guarantee replacement sooner, not later.

Other than that   

[OlJarhead]

http://www.amazon.com/Charge-It-Concentrated-Battery-Additive-oz/dp/B004DJCS2M/ref=sr_1_2?ie=UTF8&qid=1382998349&sr=8-2&keywords=battery+additive

Anybody used this stuff?  I'm wondering if it would be good to add to my batteries to help them along a bit.

[OlJarhead]

Question:  if after a 3 hour equalize (31v for 180mins) on a battery bank, if the SG readings are still not where they should be is it worth doing another equalize the next day?

I'm considering a 2nd attempt to see if I can improve things a bit.

[upa]

You have nothing to loose at this point, I would continue to equalize until you see the the SG numbers you need to see.

[OlJarhead]

That was my thought.  Though I suppose you can't equalize a toasted battery into submission

My thoughts so far is that if I were to fully charge the system, then E the system for 3-4 hours and finally if I were then to shut it down before using it then let it sit 6+ hrs I should get the most accurate readings of all and then could really say one way or another if the batteries are toast.

One thing of note:  I DID see a difference after the ChargeIt and Equalize on Sunday (last day there).  I noticed that after much use (trying to use all the power I wanted with the genny set to auto start at 24v) the system just took it and at 24.6v I decided not to run the genny after all (I was going to do some carpentry).....I was impressed and for the first time in a long time the system took a dozen hours before kicking on the genny rather than the 8 hrs or so before and that with the genny set to come on about 1/2v higher than before.

SO I'm thinking I did some good