Best way to look after your Batts

[PaulF007]

Hozid guys

I know this was definitely asked somewhere but I cant find it. I am slowly getting my system running smoothly and everybody is just about trained. 

The last three weeks or so my batts has not gone below 87% soc and I read somewhere that it might not be a good thing , something to do with only the "top" part of the plates working and they can calcify or something. 

Should I discharge the batts deeper from time to time and if so how deep and how often?

[Guest]

31 minutes ago, PaulF007 said:

Should I discharge the batts deeper from time to time and if so how deep and how often?

On Trojan's I have been told it is a good idea to push them now and then.

[___]

30 minutes ago, PaulF007 said:

only the "top" part of the plates working

That's like the blonde joke of "only the bottom part of the tyre is flat". No, not how it works. With flooded batteries there is SOMETIMES an issue with stratification, in that the electrolyte might not be consistent across the whole plate (with higher liquid densities sitting at the bottom), but a good charge cycle will sort that out. With AGMs... no such thing. Gravity does not determine where the chemical reaction takes place :-)

I heard similar arguments though, but it has a different basis. Basically, if you look at the cycle life of most batteries, there is little difference between permanently leaving them on float of doing a shallow cycle. So the 25% cycle comes mostly from there (as far as I know?), because such a shallow discharge does not significantly shorten the life any more than "not using" them at all.

Trojans (flooded batteries) need a good boil every now because of the stratification issue. With AGM I wouldn't bother.

[KLEVA]

Late, but my 2c...
It took me a while to realise that the batteries are almost the key component in a Solar setup, and usually the most expensive.

A good flooded Lead/Acid or similar combo seems to work well when they are at Float/small charge for about a month, but can die quite fast after that if not "whacked" (my term, definately not technical). I have quite a few "solar" setups, besides the obvious household, including electric fence, alarm and gate. I keep them all seperate and have realised that the normal lead/acid battery needs to be taken "offline", with no charge, at least once a month or so. I am not talking about a complete drain, but just so that it gets to about 60% (determine that how you will or with whatever you can, even a multimeter can give you a very basic idea). Then charge it properly with a decent battery charger that can deliver the right charging current, or if your solar setup can deliver the right Amps, then let it do the job...

I haven't replaced any Lead/Acid batteries in 4 years, including the cheapie gate and alarm ones. And the Deep Cycle that operates all my internal motors (heavy draw low charge), I just disconnect from the charge for 2-3 days (if the weather hasn't already done that for me), and charge with a 10A cheap car charger for a day (which gets its power from my house solar panels)... So not losing anything, just some attention.

As I have said before, anyone who thinks solar is a "install and forget" setup, is going to lose a lot of money and be very frustrated.

Now, the Gel battery setup is quite different, although they don't need that kind of attention while on Float, they can still develop the "calcification" that tries to kill Lead/Acids. Think about a Gel battery as if the liquid inside a normal Lead/Acid has been replaced with Jelly/Jello/etc. It doesn't move around as much, if any. So this is great for charging and keeping the calcification and stuff to a minimum, it can't completely stop it. And worst of all, that calcification can't fall to the bottom of the container. This sounds bad, but still makes a Gel battery a much better option (if it's not all in one place it is more difficult to join together and short/damage the plates), but it makes charging and restoration much more difficult.

You now will have to try "boil" a jelly rather than a liquid when charging, so Gel batteries need a much higher charging current and voltage when trying to "boost". A Lead/Acid can get away with a 14-14.5V boost ("decalcification") charging voltage to "shake" things up, however a Gel battery will need 15V+, some as high as 16.7V.

Hope that helps explain some of my thoughts and experience, and that it it useful.

[superdiy]

12 hours ago, KLEVA said:

You now will have to try "boil" a jelly rather than a liquid when charging, so Gel batteries need a much higher charging current and voltage when trying to "boost". A Lead/Acid can get away with a 14-14.5V boost ("decalcification") charging voltage to "shake" things up, however a Gel battery will need 15V+, some as high as 16.7V.

I'm not so sure about that.  If you quickly google the topic, you will find many references which warns against/discourages "equalize" charges for gel and AGM batteries.

http://shop.pkys.com/Battery-Equalization_ep_44.html

Equalizing AGM and other sealed batteries is a bit more tricky. The bubbling electrolyte results in some loss; electrolyte vapor exits the vent caps. However because there is no way to replace the lost electrolyte it is obvious that a different strategy is required. I couldn't find any manufacturer that recommended equalizing Gel batteries. These batteries are highly sensitive to over-charge and equalizing is not going to work for them. However although I did find a manufacturer that definitely did not recommend equalizing their AGM batteries (Trojan) I did find at least one manufacturer (Lifeline) that did recommend equalizing their AGM batteries.

 

Lifeline use the term "Conditioning". They say this should only be done when the battery is showing loss of performance due to having spent extended time in a partial or low state of charge, or that don't often get charged above 90%  (Cruisers that never come to the dock please take note!) 

 

Lifeline AGM instructions:

To apply a conditioning charge, first go through the normal charge cycle to bring the battery to full charge. The conditioning charge should then be applied by charging for 8 hours. At 77°F (25°C), the conditioning voltage should be set at 2.58 VPC (15.5 volts for a 12 volt battery). The conditioning voltage at other temperatures is shown in Table 5-2. By using the temperature compensated conditioning voltage, batteries that are not in controlled temperature environments may be conditioned without bringing them to room temperature. If temperature compensation is not available, it is best to bring the battery as close to room temperature as possible before applying the conditioning charge.

 

http://www.mkbattery.com/content_container.php?page=downloads-and-technical-reference-faq

Q: How often should I equalize my MK GEL Batteries?

A: MK GEL Batteries never need to be equalized. Here is why: ...
 

http://www.sailnet.com/forums/island-packet/18498-equalizing-agm-batteries.html

 

http://www.trojanbattery.com/tech-support/battery-maintenance/

Equalizing
FLOODED BATTERIES ONLY...

 

http://all-about-lead-acid-batteries.capnfatz.com/all-about-lead-acid-batteries/lead-acid-battery-charging/equalizing-charge/

Applying an Equalizing to VRLA batteries.

Balancing AGM or Gel batteries with an overcharge is not something a lot of battery manufacturers recommend.  This is partly due to the fact that you cannot check the specific gravity of the electrolyte.

Further, the nature of the equalization is one where some electrolyte will likely be boiled off.  Being sealed batteries, it is impossible to refill the electrolyte with distilled water.

While this could be a point of concern about AGM and Gel batteries, it is important to note that the manufacturing deviations between cells (that cause imbalance) are not as great in the VRLA as they are the serviceable flooded lead acid battery.

That said, people can and do apply equalizing charges to AGM and Gel batteries.   People doing such a thing are either ignorant or have developed a pretty good “feel” for performing this maintenance step.

[___]

1 hour ago, superdiy said:

discourages "equalize" charges for gel and AGM batteries.

Yup. You shouldn't do it unless you had a deep discharge event and/or the bank is out of balance Such a charge will lose some of the electrolyte and since you cannot replace it, you can obviously only do this so many times before you've killed the battery.

So careful conditioning, yes. Scheduled equalisation, no.

[KLEVA]

Sorry, re-reading my post does make it sound like I am talking about "equalisation" for Gel. Read the same with the term "conditioning" and "restoration" being the same thing, and it will make sense. It is for when the calcification in Gel gets to the point of shorting plates, reduced "power" (the term used by Lifeline).

Hope that clarifies.