To measure drain on the battery, you need a dvm set to measure amps. It needs to be connected in series with the vehicles electrical system.
So, disconnect the negative terminal and join the clamp to the positive of the meter, then the negative of the meter goes on the negative battery terminal
The dvm will show current drain. a few mA is normal (you'll notice a bit more if the interior light is on). Stuff like putting the ignition/heated rear window on will make it shoot up.
If you have a high reading with things off, try pulling fuses and seeing which one causes it to drop. This will tell you roughly which circuits are causing a drain and you can go from there
Fire bad, tree pretty
Took it to a garage the other day he couldn't find any drain.he said its the battery? Its a new one I said.any way went back, got battery changed again but this morning it was reading.12.4 volts so its draining again?? But he checked it all and no drain??.may be it starts to drain a few hours after its been turned off??
(18-02-2016, 11:18 PM)Johny555 Wrote: Took it to a garage the other day he couldn't find any drain.he said its the battery? Its a new one I said.any way went back, got battery changed again but this morning it was reading.12.4 volts so its draining again?? But he checked it all and no drain??.may be it starts to drain a few hours after its been turned off??
If you are measuring wright you have a voltage drop of about 0.2v per 24 hours. That gives roughly about 2.5A discharge rate.
That is roughly 30W of discharge power. First you have to find if that discharge rate is intermittent. For example. Every time you turn
off the engine you have discharge. If that is the case then you can find out fast what is the cause.
Follow post by Kez. Pulling fuses...
If discharge is intermittent then you have a daunting task of finding it. It involves 250A current shunt. Precise voltmeter and lot,lot of time.
Last time , 10 years ago, it took me 6 months to find out intermittent current drain on volvo car.
It turned out to be rear window wiper motor.
Yeah I thinks intermittent today battery read 12.6.1 volts? Was stood 24 hours.and another day it will read 12.4 volts next day if left 12.2 volts? Maybe just buy a booster pack just in case..its driving me crazy..lol..
(19-02-2016, 05:30 PM)Johny555 Wrote: Yeah I thinks intermittent today battery read 12.6.1 volts? Was stood 24 hours.and another day it will read 12.4 volts next day if left 12.2 volts? Maybe just buy a booster pack just in case..its driving me crazy..lol..
Then, I will explain from memory. You have to buy shunt: http://www.ebay.com/itm/250A-75mV-DC-AC-...SwKtlWq4AY
Any shunt will be ok. It needs to be at last 250a.
And you have to buy: http://www.ebay.com/itm/Digital-Multimet...SwuTxV8iV4
Any multimetar will be ok, as long it can measure mili Volts. It is best that multimetar has it's power supply so it doesn't interfere with measurement.
An also buy cheap ones with No auto shutdown option.
Then you have to wire it like this: http://tech.mwands.com/connecting-amp-me...hunt-bars/
I have elongated wires from multimetar and mounted it inside cabin at central console near shiftier. Each time I have started the car I started
the multimetar also. When the trip is over, engine off. For 5 minutes I would watch mulitimetar. Then one day , after 6 months I saw that
there is a power drain. Immediately started to pull fuses and found out that it was rear window wiper.
Yes it is a daunting task and I wanted to give up many times... but in the and It payed off...
Hope it helps.
I would fully charge battery AND LEAVE IT DISCONNECTED. After 24 hrs measure the voltage again across the battery. You may have a faulty cell pulling it down. Seen this before on new batteries.
(10-02-2016, 04:32 PM)geoff Wrote: Measure battery voltage with engine off, disconnect terminals overnight to eliminate the battery with absolute certainty.
Next day disconnect the battery feed to the alternator in case this is pulling the battery down.
Have you tried doing this yet from seven posts back ?? It is quick and simple and definitive. Once done you can move onto the more difficult and time consuming / frustrating aspects.