Just been to collect our van from storage and have found that the battery was totally flat. I've had a look around but can't find anything that has been left switched on!
Fridge off, lights off, aerial off and we don't have an alarm.
Any helpful ideas on how I can trace what is draining the battery ?
All you can do is charge it up & leave it disconnected for a few days. If its lost its charge after that short time, its had it. If there is a current drain while battery is connected then this will show if you put a meter accross terminals.
Hi clever. It depends what you want to read. If you want to read amps (current) being drained, then you are quite right. You need to put an ammeter in one of the leads. If you want to read volts, you put a volt meter across the battery terminals.
I haven't tried one of those meters from Maplins, but if you have a fuse box with those blade-type fuses, it should work fine. Obviously, if you have more than one thing running off each fuse, it will only tell you which fused circuit is the problem, not which individual item.
Quote: Originally posted by clever on 13/4/2014
I thought I would need to disconnect one of the terminals and put the meter in the circuit. Is that not the case ?
Yes sorry I was not clear, that is correct. But a multimeter set to m/amps would do the job, a cheap one is only a few quid & you can use it to check voltage as well.
Before you do that though charge battery & leave disconnected for a few days as suggested. 24hrs after charging, a good battery should read about 12.7v & a few days later the reading should be similar. If voltage is well down from that then its had it.
If battery is ok then connect up & check if there is a discharge, if there is then all you can do is disconnect things until discharge stops & you have found problem.
If when the battery is charged, there is a small spark when you connect and disconnect the battery terminal there is a discharge. It's suprising how small a current you can see. just connect one terminal and dab the other on the battery terminal post.
It's no good trying it until you know there is some charge in the battery.
Thanks for all the advice. We are going away this week so I won't be able to leave the battery disconnected to test for discharge. As long as it holds enough charge so we can use the motor mover to get the van off the drive we should be ok.
I think I will get one of the Maplin testers as it looks like a nice little gadget !
My gut feeling is that the battery is OK and I have left something on, but it will bug me until I find out what it was.
I would go along with what both michell8 and navver say, but personally I would use a multimeter that could read at least 5 amps at first. If the meter can only read milliamps, you could overload it if the drain is more than one amp.
The Maplin unit measures up to 20Amps in increments of 1mA and copes automatically with polarity.
It even can be left permanently installed with the fuse functioning as intended, and a reading available only when the on meter switch is "on". Thus, I find it good for permanent installation in a solar cell connection, so as and when I wish I could check the yield from that.
I also used it to check systematically the drain from all the users in the caravan, switch on lights record drain, heater fan at various settings etc.
Then of course it's useful to have as a checking unit for the car as it was designed for.
It employs a small 12 v camera battery, supplied, this is only drained when you switch it on to activate the LCD, so mine has lasted years.
I use one of these to isolate the battery when not in use. It takes a second to disconnect the battery and I know there's no chance of anything draining it. Been using it for years and highly recommend it. Available on eBay for a few pounds.
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Topic: Flat Battery Help
