Leisure Battery Health

[apole]

Hi guys,

My LB has had about 2 years use to date and I've noticed recently that the voltage when running is around 13.7v whereas the car battery is around 14.1v.

It must be getting charge as the voltage goes up when you start the car.

Is this drop normal, could the battery be starting to fail or is it more likely the split charger is developing a fault?

I have no way of comparing the charge it was receiving with what it gets now but I suspect that the battery could be getting old.

The car gets regular use, and it hasn't recently had a stint of discharge to the LB that could explain this. It's normal if you've been using the car for a while without hookup for it to take a while to recharge but this isn't the case.

I've plugged it into the mains to allow the ZIG to recharge for a day. I'll keep an eye on it.

Any advise gratefully received.

Andy

[321Away]

you'll always see a difference in voltage as the resistance from the wires and contacts causes a slight drop, typically I would expect to see a bit less, about 0.1v but dependant on your circuit type and contacts etc 0.4v isnt too bad. You cant really tell the state of a bettery wtih a meter as i've seen many batteries that give a decent voltage, but as soon as you load test them, they're dead

Julian

[apole]

Hi,

Thanks for that. I charged it up yesterday and the voltage is back to where it was now so I'll keep an eye on it.

Agreed that voltage alone doesn't mean the battery is 100%, had an issue with my other car, would go flat in a few days, no current drain, voltage fine, seemed to charge up fine etc but a new battery fixed that.

Thanks again.

Andy

[apole]

Hi again,

After a short charge the voltage on the LB was back to normal and seemed to hold and be similar to engine battery whilst engine running etc.

Today I was being driven to a large shopping outlet and was charging my laptop via a 300w inverter, powered from the LB. Voltage was down to 12.9 volts at motorway speeds. Turn off inverter and it came right up again.

I will get the battery tested but was wondering, surely the split charger should be giving the battery enough power to cater for a load like this? I'm just wondering if the relay is starting to fail and not giving the battery enough juice.

I have all connections from the LB to a fusebox on 40A cable, then each circuit on 25AMP cable with crimped joints. I am measuring the voltage using an on off on switch connected to a small digital voltmeter so I would hope this would rule out duff connections or voltage drop due to thin cables.

Does anyone know how much current you typically can get via a split charge relay (mine is a simple relay 70AMP) as fitted by the converter.

Thanks.

Andy

[321Away]

The supply current is in relation to the demand, if you have nothing running then the leisure battery will only draw a minimnal current. Inverters by design do draw a fair amount of power. What was the voltage before you turned on the inverter?

A 70 amp relay is capable of conducting a constant 70amp supply without failing, (like redline in a car) a 40amp relay can handle 70amps but will thermally overload, ie warm up and melt itself. You can get 'contact burn', when the contacts of a relay close, for fractions of a second they are close enough for an arc (spark)to from between contacts, over time, this will burn and degrade the contacts.

A COMPLETELY FLAT LB (90AH) will draw a current (spike) of approx 45 for a couple of seconds, which falls within 3 seconds, we tested the current draws to ensure we were using correct fuses. During normal everyday use you wont see anything like that, remember just cos a device has a 10Amp fuse doesn't mean it uses anything like that, most CD players have 10Amp fuses but only use about 2-3A in normal use.

Has your battery ever gone dead flat? could be a buckled plate or faulty cell. Get your battery tested and we'll see from there.

Julian