Charging 12V gel battery

G'day there
Thanks in advance for your time
I tried to charge a 12V gel battery that was down to around 10V or so.
I hooked it upto a C Tek XS 7000 charger selected "normal" mode turned it on, watched it for a minute or so and all seemed fine. Next day the fault light was lit up on the charger.
Turned it off and then back on and selected "recondition" mode which is a higer voltage I think, once again watched it for a minute and then forgot about it overnight until today. When I went and checked it the fault light was not on, but the batt was very very hot, so turned it off went to work and now hopping to get some light shed on what I've done wrong (batt now is at 11V and still slightly warm after turning it off 12 hours ago). Woops

Thanks again
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Reply By: Sand Man (SA) - Wednesday, Jan 13, 2010 at 19:58

Wednesday, Jan 13, 2010 at 19:58
Hi Scott,

If the battery measured 10v the chances are it is beyond recovery.
10.4v is dead flat and a battery in this condition has probably reached the end of its life due to calcification. In a severe state the recondition mode will not dislodge this deposit and the battery is unrecoverable.

Gel batteries also dislike a higher voltage being applied

An extract from states their dislike of gell batteries for this and other reasons.

Gelled electrolyte

"Some disadvantages of gel cells is that they must be charged at a lower voltage (2/10th's less) than flooded or AGM batteries. If overcharged, voids can develop in the gel which will never heal, causing a loss in battery capacity. In hot climates, water loss can be enough over 2-4 years to cause premature battery death. It is for this and other reasons that we no longer sell any of the gelled cells except for replacement use. The newer AGM (absorbed glass mat) batteries have all the advantages (and then some) of gelled, with none of the disadvantages."



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AnswerID: 399242

Follow Up By: Scottx - Wednesday, Jan 13, 2010 at 20:20

Wednesday, Jan 13, 2010 at 20:20
Thanks mate
I'll check out prices for a new batt before our next trip

FollowupID: 668221

Follow Up By: RV Powerstream P/L - Thursday, Jan 14, 2010 at 09:11

Thursday, Jan 14, 2010 at 09:11
Sand Man
There are Gels and there are Gels like there are AGMs and there are AGMs and AGMs are not a later invention as they were first developed in the mid 1980,s for the US Army and consisted of a few high recombination batteries from about four manufacturers.
They are low acceptance voltage but high input batteries .

The later AGM batteries from Asia cannot be compared with the original.

According to Dr Brown from Battery Energy Systems Australia the only ones that can build decent Gel Batteries are Aussies and the Super Gel Battery designed in conjunction with CSIRO and Telstra have an acceptance voltage equal to open flooded wet cell batteries and also have an acceptance to a higher operating temperature than most other batteries.

This can be proven by at least one Telstras remote operation of 11 repeater stations with in 300Kls of Birdsville that used Battery Energy Gel batteries for the total communications for that area and have I believe been running in excess of 7 years now.

The Super Gel battery has a design life of 20Years in a standby situation and has a full replacement warranty of 5 years in a designed installation.

A battery is basically a dumb waiter for storing power and normally if not maintained and or not used in a designed application is generally murdered.

You cant blame a battery for that and that is not just Gel its all types.
FollowupID: 668290

Reply By: Member - Phil G (SA) - Wednesday, Jan 13, 2010 at 21:19

Wednesday, Jan 13, 2010 at 21:19
Any battery that is hot after coming off a charger and reading 11V is dead - it has dropped a cell.
I'd be guessing your gel battery has been dead all along.
That is why the fault light came on the Ctek.
Out of interest, what size is the gel battery?

AnswerID: 399261

Follow Up By: Scottx - Thursday, Jan 14, 2010 at 04:57

Thursday, Jan 14, 2010 at 04:57
It's an Apollo HZY 12 - 80 . So maybe that makes it an 80amp? It seemed O.K about 4 months ago when we picked up the second hand van (about 12.8V and I thought higher with the power cord plugged in from van to power point).
But the kids had the lights in the van turned on using the batt power only. Then I forgot about it running the batt down and now it seems too late.
FollowupID: 668275

Follow Up By: Member - Mike DID - Thursday, Jan 14, 2010 at 08:44

Thursday, Jan 14, 2010 at 08:44
Leaving any Lead Acid battery at less than 100% charge is a death sentence.
FollowupID: 668286

Follow Up By: Gronk - Thursday, Jan 14, 2010 at 10:27

Thursday, Jan 14, 2010 at 10:27
If you ran it down to 10V from leaving the lights on......and recharged straight MAY have saved it.......but leaving it in that's gone !!!!

Amazing the ammount of people who think the idea of a deep cycle batt is to run say lights until they start going dim, then thats the tell tale sign to recharge ??
FollowupID: 668299

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