"Smart" charger wont charge diesel battery

[elCamsterino]

Hi everyone,

I have a RAC smart battery charger (HP157) and a diesel battery (73Ah 100 cca 680A).

I cannot get the battery to charge. I've measured the voltage at 5.6V and its not swapped polarity.

As per the manual I tried to charge on bike mode ( for severely discharged batteries) but to no avail...

If anyone has experience with this charger, I'd very much appreciate your help

Thanks

 

[Peter.N.]

My son bought one of these and had similar problems, I checked it with a meter and although all the lights were flashing impressively there was no output. If its new I would be inclined to take it back and get a refund and buy a good old fashioned type with a transformer in it and a meter on it so you can see what's going on. As he bought this one some time ago we had to throw it out, my experience of these or at least the ones I have come across is that they are rubbish.

Peter

 

[elCamsterino]

did you measure with the battery connected? the manual says there would be no charge...

just wondering... I have very little experience with batteries and any info would be an advantage

 

[elCamsterino]

sorry, forgot to mention...
its about a year old, used it to charge the battery of my old 525tdi BMW and it worked a treat...
its been in the back of my van for a while though and might have got a bit bashed about... doesn't look damaged though.
thanks

 

[elCamsterino]

OK here's some more info...

It IS putting out a charging voltage, about 15V for a few seconds then it sees the battery as full and goes into standby.

Won;t even entertain the motorbike mode but stays on for a few seconds on car and winter modes

thanks

 

[Belle427]

if you measured the battery voltage of 5.6 volts its knackered.

 

[CylonRaider]

My son bought one of these and had similar problems, I checked it with a meter and although all the lights were flashing impressively there was no output. If its new I would be inclined to take it back and get a refund and buy a good old fashioned type with a transformer in it and a meter on it so you can see what's going on. As he bought this one some time ago we had to throw it out, my experience of these or at least the ones I have come across is that they are rubbish.

Peter

Indeed..
My 30 odd year old Absaar charger still works when called upon.

 

[HH1]

Can only agree with Peter.N.
Had a battery which was severely discharged and tried a Halfords “smart” battery charger on it. Didn’t want to look at it. Left it overnight and still nothing happening next morning. Dug out the old charger and next morning had the battery charged.
I will add that the smart charger does charge/top-up batteries which are only partially discharged.

 

[davegsm82]

Smart chargers often see a fully discharged battery as faulty. 5.6v is usually absolutely terminal for a lead acid battery, I'm surprised your charger brought it back from the dead.

If a battery is failing then on connecting the charger it may be able to drive it to 15v because of the sulphation on the plates. Only a long, slow, trickle charge from a traditional charger will have any chance here.

Dave.

 

[Peter.N.]

I have a Crypton fast charger that I got from the scrapyard about 40 years ago, I repaired it and it worked a treat - still does.

Peter

 

[HERTS P&D]

As the old saying goes 'they don't make them like they used to'

Andy

 

[voicey]

I successfully recovered an almost new Bosch battery from 0v across the terminals with an Optimate 4 (which puts out 0.8 amps).

I had an accident where my car was written off - it was in storage for 3 months until I bought it back as part of the settlement. When I got it home there was nothing across the terminals. I had the battery connected to the car and used another battery to provide 12v into the car via the jump terminals. When I connected the optimate charger it saw the 12v and started charging. I then disconnected both batteries whilst leaving the dead battery connected to the charger.

It took 10 days to fully recover!