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The mkiv Supra Owners Club

I think I have found what is draining my battery


China Man

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I connected up my mutimeter in series with the car battery. I remove the fuse one by one from under the bonnet.

 

Orginal reading 0.05 with a 10A setting

 

By the time I remove the 20A fuse which the inside cover say HEAD and some japanese writing the reading drop to 0.02

 

Non of the other fuse make any difference except that HEAD fuse. I think that fuse provides power to my Head unit and keep the battery or radio settings? My head unit have a face that can be removed and once the fuse is out the red led stop flashing.

 

My question is that is 0.05 to 0.02 a big drop? is that why my car won't start after 3 weeks of idle?

 

Many thanks in advance

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If my muti meter is set at 10A and the reading is 0.02 what is it in mA ? is that acceptable battery drain?

 

20mA

 

So if you have a 60Ah Battery (fully charged) then it will last 60/0.02 = 3000H ~125 days before being completely drained. I would hazard that after 30% discharge or 40 days the car won't be able to start, but other factors affect the battery life like temperature, age etc.

 

At 20mA 0.02A your car should start after 2 or 3 weeks without use. But if you are leaving it stood for that long it would be better to disconnect the battery.

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Many thanks kjgreen3

 

so my head unit caused the drain from 20mA to 50mA, I think I will take the Head unit out and disconnect the permenant live since I don't listen to the set radio station anyway.

 

I have a battery kill switch installed already and I have been using that to keep the battery alive and it works. My worries is that by using the kill switch at my battery terminal it will cut supply to the clifford alarm and eventually the siren back up battery will be ruined because of the drain?

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Great thread, I am having battery drainning issues too I'm going to try testing the way you did..! My is much worst though it drains in 8hrs.

 

Is your battery kill switch the 'brain batterty' that it disconnects auto when the bettery drains to a certain voltage? and is re-connected via remote control?

 

I am going to buy one of these to tie me up till I find what's wrong with it.

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Aftermarket alarm and the recent recent cold weather will do in a battery right now. An alarm will be a constant draw on the battery as of course it's powering it's ECU as well as all the sensors it has.

 

Did 4 miles in 2 weeks in my car, battery's probably 3 months old, went to start it today and stone dead.

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Blimey, mine sits for 6 weeks at a time, and fires straight up.

 

Are you in Dubai? My NA in the winter needed driving once a week to keep it going. Used to do a 40 mile round trip to keep iit sweet. If we got to a fortnight it was dead, never really allowed the new battery more than a week without use.

 

With such limited use, you should consider a float charger, this will stop the battery deep cycling and shortening it's life. In the long term they pay for them selves.

 

Is this like a trickle charger?

 

H.

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I do have a optimize battery trickle charger and that works well. I need to make a charging station e.g. something plug and play style so the charger sit indoor and a connector somewhere accessable under the car.....

 

My clifford siren is damaged by water and going to be replaced, I asked for the auto start option which can start the car up when the battery is low and got a quote of 249 fitted :0 not going for that.

 

The battery kill switch is a turn key at the battery terminal, works a treat but once my alarm is fixed I am going to have the car on an always charging option, I don't want the battery in the siren getting ruined by not running the alarm permanently.

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I asked for the auto start option which can start the car up when the battery is low and got a quote of 249 fitted :0 not going for that.

 

What an odd system! It just starts up randomly wherever the car may be? Then leaves it idling for however long it wants? Sounds a bit silly to me.

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lol, a bit more than that.

 

It detect the voltage, if it drops below a set level it will start the car to charge the battery. It is part of the remote start function, for me its like a boys toy more than anything.

 

I'd hate that!! It's not good for the engine to start it, leave it idling then switch it off again!!

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No, im not in Dubai! Ive got a Meta M99 /T2 alarm, goes into sleep mode after a few days. Its got the stupid flashing lights too, so does my cd player (security light).

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spend 130 pounds on a new siren today and now all working. I have a Oxford Otpimizer charger, now I need a way to extend the charging wire from the charger to the car.

 

Can anyone recommand a outdoor connector which will less likely to rust? I am thinking of making a connection to the battery with a connector which I can plug and unplug from the under the car.

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How long will the connection need to be? What voltage are you thinking of running to the car, 240 or 12?

 

I have fitted a switched charging socket in my boot, the 12 volt wires from the charger are covered by the seals either door or boot. That way I have no issues with waterproof socket or grovelling under the car in the rain. I can also use the socket to charge my lap top or camera batteries etc when the car is driven

Edited by Terminator (see edit history)
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I think I will keep the charger indoor and extend the 12V lead to cover the outdoor, all together 4-5m max.

 

I bought some molex connector and inline fuse, should be here Wed this week. I want it to be neat and easy to use e.g. plug and play and I don't want it to rust or short circuit :)

 

should be fun

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