Re-charging a dead flat deep cycle battery

**d2dave** · 2nd July 2014, 07:58 PM

Originally Posted by LandyAndy

Nope,its a 25amp unit.Has a heat sensor on the posative lead to prevent overheating of the battery and the charger is self regulating.
Andrew

Andy. I have the same charger and I was of the impression that the temp sensor is for ambient temp, not battery temp.

I just had a look at Ctek's web site and this is what it said.

"and a temperature sensor for optimised charging regardless of the weather conditions."

MXS 25

If the batteries have been very flat for eight months I don't like your chances.

**dswatts** · 2nd July 2014, 08:04 PM

Use jumper leads between the 2 batteries, will charge them slower as Drivesafe suggested

**CraigE** · 2nd July 2014, 08:10 PM

Andy,
I have had to on occasion use my big workshop charger to kick in batteries with low voltage and then put back on the CTek. I have also used a set of jumper leads from a charged battery.
I have been learning a bit about using a charger to boot nicad batteries and get more life out of them. Have successfully got a couple of torch and power tool batteries revived.
Cheers
Craig

**CraigE** · 2nd July 2014, 08:12 PM

Originally Posted by drivesafe

Another trick to try to bring back exceptionally low batteries is to get a solar panel, with NO REG and connect it directly to each battery and leave it for a few days.

This is actually much kinder on the battery.

Tim,
What is the risk of doing damage to the batteries with overcharging?
Cheers
Craig

**drivesafe** · 2nd July 2014, 08:32 PM

Hi Craig, there is actually very little likelihood of overcharging flat batteries because even when using say a 100w solar panel, it will take quite a few days to get the battery back to a state of charge where the solar panel could over charge the battery.

The intention is to use the solar panel to get the battery up to a voltage level where the charger can than be used.

Thanks to my crap Range Rover doing an alternator, my cranking battery was discharged down to 7 volts on consecutive days, after recharging.

The battery no longer held a charge for more than a day or two, so was in all respects, stuffed.

So I connected up an 80w solar panel, minus the reg and left it on for three days.

The final voltage was 17.4v, when I disconnected the solar panel on the third day, and the battery was bubbling away.

The battery lasted another two years before it started to loose it’s charge again.

It was replaced then.

I do not recommend over charging AGMs but wet cell batteries, particularly Calcium/Calcium batteries, will tolerate some pretty high voltages for short periods of time and this can do them some good, if they are not already totally stuffed.

**LandyAndy** · 2nd July 2014, 08:45 PM

Both batteries now linked via jumper leads and charging

.
Thanks People.
Andrew

**DiscoKym** · 2nd July 2014, 09:37 PM

I have read that the standard calcium battery charging voltage is 15.1V..

My Ctek has a kick it in the butt 16v feature..

**Graz** · 3rd July 2014, 11:12 PM

Hi Andrew

Did you get the link I sent you for the solar battery charger regulator?

Graham

**LandyAndy** · 4th July 2014, 07:25 PM

Yes Olde Timer,will be getting one thanks.
Andrew

**LandyAndy** · 4th July 2014, 07:29 PM

These batteries arent charging.The Ctek seems to cut out at 6.2 volts,batterys then staibalize to 5.2 volts.
Stopped the jumper leads when the charger first started kicking out.
Plan is to go back to "supply charge @ 13.6V" with both batteries connected via jumper leads tommorow whilst Im around to keep an eye on them.
Any thoughts beside STUFFED?????
Andrew

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