i've had problems with battery drain for ages, and been through about 3 batteries in almost as many years. as long as I run the Z at least once in a 5-day span then it charges up enough (e.g. to and from work) and isn't a problem, but after standing only 3 days unused, it only just started this morning, and worryingly, struggled a little bit to start this evening when leaving work. the voltage reading (usually 14+ when charging and 13.8 when idling) only reached 13.8 when driving, and sat at 13.3 when idling.

 

the battery is approx. 6 months old and is a good make.

 

...so I'm going to buy a multimeter from halfrauds and set about molesting the fuse boxes.

 

my main question though is, what would be the 'normal' battery drain for a Z that has several parasitic units, eg. boost controller, alarm/immob., head unit, Power Meter / RSM / any other fancy unit made by Blitz/Apexi, etc...

Sounds like your alternator is not charging properly, not sure though.

Agree with daveb on this one, i think it does not matter how many parasitic add-ons you have, just as log as the alternator is properly charging the battery.

 

Do you have an ice install? If so, this could be draining the battery.

 

Al.

Surely Dave all the 'ad-on' bits will be cut of power when ignition is off?

Pull the neg lead off and put a Ammeter between it and the battery with EVERYTHING off (interior lights etc) and see what it pulls.:wink:

No more than 0.3 amps is about right iirc.

No more than 0.3 amps is about right iirc.

 

Ideally you want

 

0.3 amp draw on say a 60Ah battery would mean the battery would be completely dead flat in around 180 hours (or 7.5 days).

 

:smartass:

thanks for the responses. i think the alternator is fine otherwise the car would have packed in months ago. i understand that some electronics in the car, even stock ones like clock, ECU, radio, take a small charge from the battery, and that its only really old cars that would have zero drain due to having no electronics whatsoever.

 

I was going to try what you suggested Daz and see if I can isolate the drain by removing fuses with an ammeter attached.

You could disconnect the neutral on the battery and then put a multimeter in series with it to measure battery drain.

Did this once with my partners MX5 and found the drain (0.5A) was from the stereo. Almost like the amp wasn't shutting down when car off.

Your 13.8 and 13.3v sound a little low as well, could be a weak alternator. They don't have to fail completely.

I have the same problem with my car and I couldn't find the drain on the battery. In the end I got one of these solar battery chargers that plugs into the cigarette lighter and not had any problems so far.

I ran a few checks with my shiny new multimeter (which is now covered in oily finger marks) and I'm only losing 0.16A, but the connection to the negative terminal on the battery was loose and caked with some black powdery stuff so Ive cleaned that up and tightened it up properly. i've got other problems with the motor as well as per my other thread so let's see what happens...