Ythomit Posted January 18, 2014 Share Posted January 18, 2014 For the last couple of years I've had battery problems. If I dont drive the beast for 2 weeks, the battery goes flat. I recharge it and all is fine again, until I dont use it for 2 weeks again. During the last 2 years I have replaced the battery twice. Now I suspect there was nothing wrong with either of them. I then assumed that something was draining the battery and could only think of the alarm/imobaliser so I turned it off and left it for 2 weeks. And the battery was flat again. Any ideas would be welcome. Quote Link to comment Share on other sites More sharing options...
Guest Budz86 Posted January 18, 2014 Share Posted January 18, 2014 You may find it's actually the alternator not charging it up properly. It might be worth checking the charge level after you've been out on a longish drive, or checking the volt output of the alt with a multimeter Quote Link to comment Share on other sites More sharing options...
buster Posted January 18, 2014 Share Posted January 18, 2014 You may find it's actually the alternator not charging it up properly. It might be worth checking the charge level after you've been out on a longish drive, or checking the volt output of the alt with a multimeter Thinking the same. Or have you got a car amp for your stereo that could be staying on of for that matter any aftermarket kit? Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted January 18, 2014 Share Posted January 18, 2014 Alternator would be my first port of call, but a bad earth can also cause this. A bad earth will also often manifest itself with poor running. Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted January 18, 2014 Share Posted January 18, 2014 Disconnect the battery to save it? Quote Link to comment Share on other sites More sharing options...
Ythomit Posted January 18, 2014 Author Share Posted January 18, 2014 Hi Budz86 and buster. Trouble is that I cant see how an alternator would cause the battery to go flat only after not being driven for 2 weeks ? Unless I'm missing something, which does happen now and then Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted January 18, 2014 Share Posted January 18, 2014 Buy a voltmeter and start testing everything Quote Link to comment Share on other sites More sharing options...
Ythomit Posted January 18, 2014 Author Share Posted January 18, 2014 (edited) Swampy442 : Not really a solution... Edited January 18, 2014 by Ythomit (see edit history) Quote Link to comment Share on other sites More sharing options...
Ythomit Posted January 18, 2014 Author Share Posted January 18, 2014 Buy a voltmeter and start testing everything Looks like the only solution Quote Link to comment Share on other sites More sharing options...
inazone Posted January 18, 2014 Share Posted January 18, 2014 Mine does the same, I think it is to do with the alarm and stereo etc. Even though it is a small drain it will flatten the battery. I bought a red top optima battery and that still goes flat although after about 4 weeks of not being used. Funny enough my cars on charge now! if you can use one of those small trickle chargers the ones that are safe to use while connected to your car. Lidl and aldi do a great charger for about 15 quid. I think Lidl have them in now. Quote Link to comment Share on other sites More sharing options...
Ythomit Posted January 18, 2014 Author Share Posted January 18, 2014 As a rule... Can an alarm/demobiler system use so much power that 2 weeks is all the battery can supply ? Quote Link to comment Share on other sites More sharing options...
Ythomit Posted January 18, 2014 Author Share Posted January 18, 2014 Mine does the same, I think it is to do with the alarm and stereo etc. Even though it is a small drain it will flatten the battery. I bought a red top optima battery and that still goes flat although after about 4 weeks of not being used. Funny enough my cars on charge now! if you can use one of those small trickle chargers the ones that are safe to use while connected to your car. Lidl and aldi do a great charger for about 15 quid. I think Lidl have them in now. Mine's on charge too Maybe I'll just have to remember to spin it at least once a week Quote Link to comment Share on other sites More sharing options...
inazone Posted January 18, 2014 Share Posted January 18, 2014 Here you go the link is below. http://www.lidl.co.uk/cps/rde/SID-B8CB14ED-8583A802/www_lidl_uk/hs.xsl/our-offers-2491.htm?action=showDetail&id=9103 Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted January 18, 2014 Share Posted January 18, 2014 Yes, anything that draws a current will drain the battery, it will state in the alarm instructions what the draw is. My suggestion wasn't flippant though, you don't use the car for 2 weeks, disconnect the battery, easy. If its stored outside maybe look into one of those solar powered battery top up thingies? Quote Link to comment Share on other sites More sharing options...
Ythomit Posted January 18, 2014 Author Share Posted January 18, 2014 Yes, anything that draws a current will drain the battery, it will state in the alarm instructions what the draw is. My suggestion wasn't flippant though, you don't use the car for 2 weeks, disconnect the battery, easy. If its stored outside maybe look into one of those solar powered battery top up thingies? Sounds like the only option. Ill need to get a small enough charger to fit under the bonnet. I'll check out the one suggested by inazone. Thanks inazone and all others. Quote Link to comment Share on other sites More sharing options...
inazone Posted January 18, 2014 Share Posted January 18, 2014 Don't forget most supes are not stock therefore everyone has gauges, modules attached etc.. .. These all require power to keep the memory settings. You could check the amperage draw from the battery while the car is off by putting an ammeter inline with the positive battery terminal, that will tell you your amp draw. Quote Link to comment Share on other sites More sharing options...
Havard Posted January 18, 2014 Share Posted January 18, 2014 Quite easily but to have replaced two batteries in a relatively short period of time would either suggest the alternator is not charging as well as it should or that there is a small drain taking place. Batteries also struggle to recover if completely deadened regularly. We have killed ours three times in the last twelve months and it is now around half as good as it was. I would get a CTEK trickle charger to keep it topped up but also if it gives the battery longer life when not in use. I have had ours on charge for a few weeks now and it lasted longer in the cold weather when not on charge compared to a couple of months ago, when we left the lights on twice within a few weeks. We picked up our car from Jurgen in September 2010 and ours still has the same battery it had in Japan. Having a charger/conditioner may solve your problem, especially if it is sitting still for over a fortnight in cold weather. H. Quote Link to comment Share on other sites More sharing options...
Morpheus Posted January 18, 2014 Share Posted January 18, 2014 Mine does the same and I always assumed that it was the alarm. Next time you replace the battery, get an Ultima Yellow, Red or Blue Top deep cycle if it's going to sit unused for weeks at a time. Also cold, damp weather drains them by moisture tracking and shorting between the battery terminals which is why people recommend insulating them with a finger full of petroleum jelly like Vaseline. Another tip is that if the battery is dead and when you plug it in, your charger won't charge the battery without tripping into trickle mode as if it's damaged, just keep re-connecting it and letting it trip and after a few attempts the battery voltage will increase to the point of charging fully in one go. My Halford's automatic charger does this as it needs the battery to be above x volts ( typically 11.3) or it thinks it's beyond repair and won't bother. Lead acid batteries can be 'damaged' by allowing them to drain completely so if possible, never let it go flat before re-charging or it will develop a coating on the lead inside reducing it's performance. Optima batteries are designed to be more resistant to this effect. The Red Top is best for keeping it's voltage up when not used for long periods but most car enthusiasts buy Yellow Tops as they have a bit more deep cycling capacity. Blue Tops are typically used in boats and RV's that have more accessories running off them and they can be drained further without damage. Halford's Calcium are a cheap but good battery with a 4 year guarantee the last time I bought one. They still go flat in a week without being used though! Quote Link to comment Share on other sites More sharing options...
supersupra3 Posted January 18, 2014 Share Posted January 18, 2014 same problem here ctek trickle charger is the answer Quote Link to comment Share on other sites More sharing options...
GMan Posted January 18, 2014 Share Posted January 18, 2014 Both of our Supras will flatten the batteries in two weeks during the winter if not driven, It is really a 1 minute job to just disconnect the negative terminal if you are not going to use it for a while. Will save your battery and a load of time getting it jump started. My girlfriend's supra started killing batteries and it turned out to be the alternator on the way out, it just wouldn't charge until it was over 3000 rpm so wasn't charging the battery most of the time. Swapped it out and problem went away. Quote Link to comment Share on other sites More sharing options...
tkddav3 Posted January 18, 2014 Share Posted January 18, 2014 Mine occasionally goes flat as it's a garage queen,'it's got a toucan. Defi's sub and amp with a road alarm. No wonder tbh... Quote Link to comment Share on other sites More sharing options...
Ythomit Posted January 18, 2014 Author Share Posted January 18, 2014 I've found a solar powered charger on-line that seems to work for other users on thier cars. You plug it into the cigarette lighter and leave the panel on the seat. Dead easy to connect/disconnect. I've ordered one so I'll let you know if it works on the Supra... Quote Link to comment Share on other sites More sharing options...
Havard Posted January 18, 2014 Share Posted January 18, 2014 I've found a solar powered charger on-line that seems to work for other users on thier cars. You plug it into the cigarette lighter and leave the panel on the seat. Dead easy to connect/disconnect. I've ordered one so I'll let you know if it works on the Supra... I've always thought they weren't particularly effective, especially in this country. You really need something that is going to keep the battery fully charged and then allow it to drop to 80% and charge again. The CTEK's are brilliant. H. Quote Link to comment Share on other sites More sharing options...
Ythomit Posted January 18, 2014 Author Share Posted January 18, 2014 I've always thought they weren't particularly effective, especially in this country. You really need something that is going to keep the battery fully charged and then allow it to drop to 80% and charge again. The CTEK's are brilliant. H. Apparently the one I'm looking at doesn't need sunshine. It's also only a tenner so if it doesn't work I wont be too out of pocket Quote Link to comment Share on other sites More sharing options...
Havard Posted January 18, 2014 Share Posted January 18, 2014 Apparently the one I'm looking at doesn't need sunshine. It's also only a tenner so if it doesn't work I wont be too out of pocket Worth a go but it has taken me a long time to learn that mostly, you get what you pay for. Hopefully it will be a cheap fix to the issue. Quote Link to comment Share on other sites More sharing options...
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