Battery charging

Submitted: Saturday, Feb 25, 2006 at 09:43
ThreadID: 31133 Views:1453 Replies:2 FollowUps:3
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Hi All,
I have a Jayco Freedom van with 3 solar panels (about220W total) across a 150AH gelcell. A BP Solar 30A regulator takes care of the charging.

Worked great on a recent 3 1/2 month trip. Now we are back home for a while and I need to maintain the charge to the battery.

What is the best float charger for this type of battery?

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Reply By: Member - Collyn R (WA) - Saturday, Feb 25, 2006 at 10:42

Saturday, Feb 25, 2006 at 10:42
Unless you live somewhere exceptionally hot, the best way to keep gel cell batteries happy when they are not in use is to fully charge them every 6-9 months and then leave them somewhere cool.

As with AGMs, gel cells have very little internal leakage and do not in any case suffer from the sulphation problems on conventional batteries left uncharged.

If you really do want to float them they you need a top quality thrre-stage charger with a gel cell cycle. But my advice is not do this.

Of all the mythology surrounding batteries, one of the biggest is that they need exercise. The opposite is true.
Collyn Rivers
AnswerID: 156980

Follow Up By: Member - Collyn R (WA) - Saturday, Feb 25, 2006 at 10:45

Saturday, Feb 25, 2006 at 10:45
Further to the above - if leaving 'van in the sun - you could if you really wished have the gel cells floating via the solar regulator - but I would first check the float voltage is as required for your gel cells. I would still prefer to see gel cells in a cool place and left alone.
Collyn Rivers
FollowupID: 411149

Follow Up By: Gronk - Saturday, Feb 25, 2006 at 12:16

Saturday, Feb 25, 2006 at 12:16
Collyn,I have a KK camper trailer with 2x 35ah AGM's and they need topping up approx every 5-6 weeks (going from 12.9 down to approx 12.4 v) I know by looking at some of the replies that their must be something ACROSS the battery but without pulling the camper apart I can't see anything that might be causing a batt drain? Would it be feasible to break the positive wire from the batts and install a manual circuit breaker in an accessable spot to totally isolate the batts when not being used?
FollowupID: 411161

Reply By: Member - Collyn R (WA) - Saturday, Feb 25, 2006 at 13:27

Saturday, Feb 25, 2006 at 13:27
You certainly can insert a manual circuit breaker. Locate it as close as feasible to the battery. (Do make sure you choose one that can be manually opened (some can only be manually reset - get back to me again if you have any problems finding one). Use one that cuts out at about twice the normal full-load current.

The voltage drop from 12.9 to 12.4 over five weeks (for a 70 Ah AGM battery bank) suggests a probable total drain of about 20 Ah - or around 0.5 Ah/day.

This is massively higher than an AGM's internal loss. Suggested causes are a radio that draws slight current even if turned off at the set (this is common - some have a second direct battery feed for internal memory etc), an exceptionally large electric clock, an electric fridge that draws slight current even when 'off' - see below.

Many electrical appliances (including some 12-volt ones) have an RFI suppression circuit on the battery side of the on/off switch. The intent is to supress interference when the appliance is switched on and off. These typically draw current of the magnitude manifest here.

If in doubt always turn them off at the wall switch - or disconnect them from the socket.
Trust this helps
Collyn Rivers

AnswerID: 157000

Follow Up By: Mike DiD - Sunday, Feb 26, 2006 at 08:03

Sunday, Feb 26, 2006 at 08:03
Or maybe the batteries are approaching the end of their life after regular deep discharging ?

FollowupID: 411301

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