Thread: Battery fully flattened - recharge or don't bother ?

What have you got to lose?
I currently have a failed wet cell deep cycle battery on my multi-stage charger where its been for two weeks, while I hope it might recover. It has charged OK but I'm not sure yet if it will hold that charge when put under a load. It was in a bad state, so I'm not optimistic, but I lose nothing by trying it. As I understand it, the charger agitates the water in the cells which may reduce the calcium buildup, or something like that.
I suggest you give it a go. Nothing to lose by trying.

It looks like I've managed to recover my 10yo ex-LR warranty battery in my club plate car after leaving the radio on for a month. The smart charger didn't want to know about it but a trickle charge with the basic charger soon had it good enough for the smart one to take over.

We have charged batteries which have gone flat for possibly months (old tractors or the spare ute etc which rarely get used). Most have been able to be recharged with the trickle charger but are not quite as good at holding the charge. Some have never worked. Still worth a go though and if you are using it regularly could be fine for ages.

Just reporting back...........

The battery got a solid charge on the vehicle alternator in the second battery position over a few shortish trips over a few days and this brought it up to a maintained charge of 10v, I then took it out and put it on the trickle for a few weeks.

It's now back in the vehicle in the starting battery position and doing its job.

Seems to now hold full charge (12.7v) between uses and continues to show green on the indicator on the battery.

It will be interesting to see how it holds up going into the cooler weather and with the sub zero nights we will start to experience in about 3 months time.

(I wonder if "alpine diesel" will be on sale again this year - locally it's just diesel with heating oil added)

I still think if I'm going somewhere really remote this winter I'll get a new start battery, but all is good that ends well.

Thanks for all the replies and opinions. Saved about $120-$130 I reckon. I'll buy you all a beer/coffee if/when we catch up.

Originally Posted by 87County

I still think if I'm going somewhere really remote this winter I'll get a new start battery, but all is good that ends well.

Laurie, If you need a new battery and are in Brissie or Sydney, check if YHI are anywhere near you. I got a very good deal through the AULRO discount Battery Discounts For AULRO members

That's good to hear.
Mine has been on the auto charger for several weeks and is now showing a surface float of 13.8 all the time. I have switched off the charger for several days and then turned it on again. Each time it reads 13.8 at startup. I have now left it on to keep slowly agitating it in the hope it recovers.
I plan to put the fridge on it soon and see how it handles a load.

Originally Posted by 87County

Just reporting back...........

............... and continues to show green on the indicator on the battery.

I'll never buy another battery that has one of these again, had about 4 or 5 over 20 +years and never get more than 3 or 4 years out of them. Could be coincidence, dunno.

Comments invited! DL

To get an automatic charger to charge a deeply discharged battery you need to connect a known good battery to the discharged one in parallel and then connect the charger to the "good" battery. The Optima instructions that come with the battery and many automatic chargers detail this.