battery storage?

Saburai · March 2015

Hello All

We will be traveling for the next six months, giving up the place that we now have. As such I'll have to break down and store our 12v system. I'll store it at a friends house until I put it back into service again when we return. My battery bank consists of four Trojan T-105's. The ballance of my small system is three 160w mono panels and a Bogart engineering SC-2030-charge controller along with a TM-2030 system monitor. My friends house is grid tied so there's no problem with plugging in a battery minder type device. Would I be better served using my Bogart engineering equipment and a small panel to keep the batteries up while I'm away? My friend will water the batteries in our absence, so no worries there.
Your input is much appreciated!

BB. · March 2015

I have an older model of Battery Minder that I use on my In-Law's car that they do not drive very much. Very happy with the results... A well charged battery and I do not need to add water (maintenance free battery). It is a newer model car with all of the gadgets that would kill the battery after a month or so of not driving.

More or less, for maintaining a lead acid battery bank, you need around a 1% rate of charge. For 2x T105 batteries, I would get around a 3-8 amp charger. If you have a smaller charger I would use once charger per battery pair. Just make sure the batteries are relatively full charged before putting them on Float (do not put less than ~75% charge battery on low current float--The batteries may take a long tome to get fully charged and can sulfate some during the process)..

Have him check the voltage/water levels ~once per month--And you should be fine.

-Bill

Saburai · April 2015

BB. wrote: »

I have an older model of Battery Minder that I use on my In-Law's car that they do not drive very much. Very happy with the results... A well charged battery and I do not need to add water (maintenance free battery). It is a newer model car with all of the gadgets that would kill the battery after a month or so of not driving.

More or less, for maintaining a lead acid battery bank, you need around a 1% rate of charge. For 2x T105 batteries, I would get around a 3-8 amp charger. If you have a smaller charger I would use once charger per battery pair. Just make sure the batteries are relatively full charged before putting them on Float (do not put less than ~75% charge battery on low current float--The batteries may take a long tome to get fully charged and can sulfate some during the process)..

Have him check the voltage/water levels ~once per month--And you should be fine.

-Bill

Hi Bill,

Thanks for the reply.
so if I understand you correctly, you're suggesting that I separate the four T-105's in to two banks and put battery minder on each?
also, would you be able to suggest a particular model battery minder?

Many thanks
Rich

BB. · April 2015

That is what I would do...

You would want around 1% minimum rate of charge for floating/maintaining your batteries... For a 220 AH battery string, you would want around 2.2 amps minimum.

Colder batteries have lower self discharge and will "age slower" (roughly 2x longer life for every 10C below ~25C room temperature).

If you batteries are stored in a warmer place, I would suggest something like 3-4 amps minimum rate of charge per string -- Just to be sure.

I don't have any specific recommendations for any model of Battery Minder--They are not cheap, but the one I got works much better than any of the cheap solutions I have tried in the past (in-laws with car that is not driven much--Cheap 1 amp float chargers would boil battery dry if not watered ever couple of months. No problem with Battery Minder).

One of the reasons I finally went with a larger Battery Minder--My in-law's car would sit for months and the internal electronics would self discharge the battery enough after ~4 weeks to seriously risk failure to crank/damage to the battery.

I used a "cheap charger" set on a 4 hour timer to float the battery and make up for discharge by electronics. Without timer, I had to check the water level every couple of months (mantenance free battery). And sometimes, they would leave the trunk cracked (trunk light on) and the 4 hour per day timer was not enough to keep up with the trunk light. A real (not cheap) battery charger designed for float has worked very well ever since (no water needed, no random dead battery).

This is the one I use (old model?):

http://www.amazon.com/BatteryMINDer-Volt-Amp-Battery-Charger/dp/B000JFLSL6

Works great--Flexible enough to use on just about any type of 12 volt lead acid / AGM / GEL battery. Large enough to float larger battery banks.

Is this the one you want (or newer model)? Not sure. Your choice.

It is large enough to charge 2-3 parallel strings of your T-105 batteries with one controller (save a bit of money).

Parallel charging the batteries should not be an issue as long as one of the cells does not suffer a short (rare, but does happen).

-Bill

Saburai · April 2015

Thanks again.

This one:
http://www.batteryminders.com/12-vol...sulfator-12248
Which seems to be there base model 12v 8 amp unit can be had for $140 shipped via Amazon prime. It seems like the way to go if I want to saddle my friend with the least amount of responsibility that I can get away with. Edited to ask if you think there is a reason to go with one of the more expensive models?

BB. · April 2015

That looks like the upgraded version of what I am using for a single ~85 AH flooded cell/maintenance free battery on my in-law's car. New feature is the temperature compensation--Nice to have, but I don't miss it--Car is garaged in very mild climate.

Think you will be very happy with this unit. Like I said, not cheap--But if you will be using for years in the future--You will have much less problems with your batteries when storing them.

-Bill

Saburai · April 2015

Thanks Bill,
the temperature compensation will be good to have. I'll be storing the batteries and equipment in central Florida in the summer.

PNjunction · September 2015

Bill - I can't believe I missed this - I too am a BIG fan of VDC's Battery Minder.

But just to show I'm not biased, I'm also a big fan of Tecmate-Optimate too.

I have the 12248 you are using along with a 2012, a 2012-agm, and a 1510.

The thing about the 12248 is that some may experience a random fallback to a 2A/Gel setting. This is normally done when you pull the leads off the battery you have set differently, or if you have a bad battery connection.

BUT, frequently overlooked if this happens is the near universal use of "SAE" quick-disconnects among all the manufacturers. Some can be pretty loose, and be a high-resistance contact. It should NOT feel warm. Personally I just wish the manufacturers would adopt Anderson Powerpoles, but alas.

Thus, when I used another manufacturers clamps that had a slightly tighter fit, my random fallback with the 12248 seemed to disappear. Eventually, since I use either clamps or ring-terminals exclusively depending on the charger, I cut out the SAE quick disconnect altogether and do a solder / shrink wrap mod.

Apparently, there are internal dip switches inside the unit you can set for a permanent setting, but this will still not fix a high-resistance loose SAE qd, even if this prevents the unit from falling back to 2a/gel mode. I haven't opened mine up to do this mod, because changing to a tighter fitting clamp set seemed to ease the issue.

Just thought I'd put this out there in case anyone got frustrated with this excellent charger.

mike95490 · September 2015

I'll add to the decision confusion process, I use a NOCO Genius 7Amp charger to keep the starter battery for my genset topped off. It claims to have brains and manual thermal compensation, gel, agm, flooded settings. Worked for 2 years so far.....

PNjunction · September 2015

The Noco Genius 7A charger is quite versatile - I have the old and the new version.

However, the Noco's only do float-monitoring, and will allow the battery to self-discharge to trigger levels you may not like, and promote sulfation walk-down over time. It also stops a bit short during the absorb cycle - put another 3 stage charger on it, and you'll spend quite a bit of time in absorb.

The cure for this is simple - use the built-in 13.5v "power supply" or "maintenance" feature to at least get in a long float. This usually requires resetting the charger and going into that mode manually - clamps off at first, and then placed on the terminals - with no spark / reverse polarity etc safety features, so be careful.

I think the reason they stop a bit short is that they are intended primarily for vehicle use, where the lack of a truly full charge is along the lines that once put back into the vehicle, and after the first start, the vehicle charger will bring it up to 100% SOC.

PNjunction · September 2015

Well, that is use the 13.5v power supply mode AFTER a normal 3 stage charge has been completed.

battery storage?

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