mx5 Paul Posted December 11, 2013 Share Posted December 11, 2013 I think I might have a battery issue, I bought a new battery almost 2 weeks ago, the input was tested prior and everything else was ok. I have been running the car daily with lights and heater most days. But this morning I went to start it and it seemed slower to crank over, it started ok though, it seemed that the battery almost doesn't have enough juice. Would this be normal for a new battery to be nearly flat inside 2 weeks. Just to also throw this in, I think that the stereo amp might be connected to a permanent Live, would this have an effect over this kind of timeline?? Not sure if its just that the car isn't being driven long enough, to go to work is about 5-6 miles each way city/surban traffic. What you think? Paul Quote Link to comment Share on other sites More sharing options...
R35LEE Posted December 11, 2013 Share Posted December 11, 2013 First this I would do is disconnect the amp map and see if it makes a difference. If not look for other drains and lastly buy an alternator it could be on its way out Quote Link to comment Share on other sites More sharing options...
Dynamic Turtle Posted December 11, 2013 Share Posted December 11, 2013 First this I would do is disconnect the amp map and see if it makes a difference. If not look for other drains and lastly buy an alternator it could be on its way out AFAIK Zed alternators are very hardy. Just as well because they are bloody expensive! Quote Link to comment Share on other sites More sharing options...
R35LEE Posted December 11, 2013 Share Posted December 11, 2013 Not expensive second hand Quote Link to comment Share on other sites More sharing options...
Dicky Posted December 11, 2013 Share Posted December 11, 2013 An easy way to check your altinator without using multimeters is to start thr car then turn on all electricals, headlights, heater, etc. Let the car tick over and note the brightness of your headlights ( best checked in the dark for obvious reasons). Then rev up the engine and you should see the brightness of your headlights come up a little. If you measured the voltage across your battery tou should see it rise from around 12v to around 14v or so but you should see an increase. If that's all ok then you may have something connected that isn't turned off when you remove your key from the ignition. Typically clocks and computer items will be maintained with a voltage supply but because they take so little from the battery it would take weeks to run your battery down. I would imagine (but not sure) that these items would take 1/10 th's of amps to operate if that. If you can get access to a multimeter with suitable DC amps range you can turn off the ignition then disconnect one of your battery leads and connect the meter in series with it. This would show you how much current is being drawn from the battery when the car is parked up. If you have say 60 amper hour battery fitted then when fully charged it will deliver 60A for 1hr or 30 A for 2hrs and so on, so you can get an idea of how long it would take to flatten your battery with what ever current is being drawn when ignition is off. Quote Link to comment Share on other sites More sharing options...
mx5 Paul Posted December 11, 2013 Author Share Posted December 11, 2013 Have put the optimate on it for the night, will see how long it lasts. Would the power to the amp really drain the battery? Paul Quote Link to comment Share on other sites More sharing options...
richmillions Posted December 11, 2013 Share Posted December 11, 2013 On a car I had a few years ago a few weeks after stereo install the battery went flat. Thought nothing of it as that battery was in the car a few years. Replaced the battery and the same thing happened again. Turns out the stereo was connected to the permanent power instead of ignition, I changed power around and everything was fine, no more flat battery. Quote Link to comment Share on other sites More sharing options...
mx5 Paul Posted December 11, 2013 Author Share Posted December 11, 2013 So if it was connected to permanent live this would mean I could turn on radio without the key being in the ignition?? Quote Link to comment Share on other sites More sharing options...
richmillions Posted December 11, 2013 Share Posted December 11, 2013 So if it was connected to permanent live this would mean I could turn on radio without the key being in the ignition?? Yea that's the way mine was done when the battery drained. Quote Link to comment Share on other sites More sharing options...
cs2000 Posted December 12, 2013 Share Posted December 12, 2013 FYI, a amp will EASILLY flatten a battery overnight if its wired to perm live. Quote Link to comment Share on other sites More sharing options...
mx5 Paul Posted December 12, 2013 Author Share Posted December 12, 2013 (edited) Thanks for that guys the battery has lasted about 2 weeks, so I'm guessing that perm live isn't the issue. I couldn't turn the stereo on with the keys out either. The search goes on!! Edited December 13, 2013 by mx5 Paul Quote Link to comment Share on other sites More sharing options...
mx5 Paul Posted December 17, 2013 Author Share Posted December 17, 2013 Looks like the issue is back, went to start this morning just managed to turn over enough to start, just trying to work out how to test everything. Someone has suggested running/driving for a bit enough to get decent charge into the battery, then disconnect the battery overnight. Then go back the next morning and see how it starts. If it starts fine, this would mean a draw on the battery, if it struggles again then battery? Remember I had both the Alternator & Starter seems fine. Where is the amp in a 350z (UK Car GT Spec) Cheers Paul Quote Link to comment Share on other sites More sharing options...
BulletMagnet Posted December 17, 2013 Share Posted December 17, 2013 On a car I had a few years ago a few weeks after stereo install the battery went flat. Thought nothing of it as that battery was in the car a few years. Replaced the battery and the same thing happened again. Turns out the stereo was connected to the permanent power instead of ignition, I changed power around and everything was fine, no more flat battery. Thanks for that guys the battery has lasted about 2 weeks, so I'm guessing that perm live isn't the issue. I couldn't turn the stereo on with the keys out either. The search goes on!! Richmillions had his stereo wired "live" not just the amp which made it possible to turn on the steroe without ignition. If you only have the amp wired live, and still have normally wired stereo, then you won't be able to turn on stereo without ignition, but it will still drain your battery. Best thing to do is to check whether the blue "Remote On" wire to the amp is wired correctly to the headunit or at all wired to anything. This blue wire (or whichever colour the installer chose) is the only thing that will turn on the amp, because the main power feed will always be wired to the battery directly. Time to start tracing wires I think Quote Link to comment Share on other sites More sharing options...
cs2000 Posted December 17, 2013 Share Posted December 17, 2013 Bm is correct. Wiring a head unit to perm live would be fine as long as you remember to turn it off however wiring an amp to perm live means just that, its always on and I have from past experience done this so I know full well it can kill a battery. The idle voltage of those things is surprisingly high. However im not clear if you have an aftermarket amp or just the stock Bose one?? Oh, and since you asked, the bose unit is in the boot, on the left hand side (if you stand facing the rear of the car) underneath the large slab of black polystyrene. If you do just have a stock amp, id rule this out as I see no good reason why you/anyone would have messed with the wiring of that. Quote Link to comment Share on other sites More sharing options...
M13KYF Posted December 17, 2013 Share Posted December 17, 2013 could be a faulty battery, it has been known Quote Link to comment Share on other sites More sharing options...
zedspeed48 Posted December 17, 2013 Share Posted December 17, 2013 It may be the alternator regular playing up I'd carry out another load test with multimeter for about 10 minutes to see if your getting 14 volts when charging Quote Link to comment Share on other sites More sharing options...
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