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Isolating the starter battery for long periods

SteveS

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Jan 12, 2013
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630
My truck is destined to spend 4-6 week periods in the dark confines of a ship container. So my thoughts have turned to how I can completely isolate the starter battery from the car systems. The 2nd/Aux battery will be isolated by virtue of the IBS split charge controller. The starter battery will have up to 6 weeks of discharge.

I initially had in mind to put a key switched isolator in the battery +ve but this is not that straightforward to do because of the fusible links and number of key wires coming off that terminal.

I could simply disconnect the whole terminal from the battery......in the dark confines of the container, twice.

I could put an isolator in the -ve terminal

I could ignore the problem.....but I have no idea what the current is with the vehicle in the unlocked state AND use the IBS 'link' feature to start the truck off the AUX paralleled to the starter battery.

Anybody have some advice/thoughts on the above? It would be interesting to know the discharge current of the car
 
Ho idea... but what's the LC's destination & why? Sounds like there's a story here??
 
Any chance you can observe discharge rate over say a week of inactivity?

I'd probably just disconnect the negative off the battery. Easy enough with one spanner and a torch really.
 
Ho idea... but what's the LC's destination & why? Sounds like there's a story here??

The truck will be in various containers over the next few years: UK to Canada; Panama to UK; UK to Ecuador; Argentina to UK; UK to Namibia etc etc as we navigate the Pan-Americas and then south Africa

If there isn't a definitive answer to the discharge current then I'll do as suggested and measure the voltage dropping off over a period of a month
 
Any chance you can observe discharge rate over say a week of inactivity?

I'd probably just disconnect the negative off the battery. Easy enough with one spanner and a torch really.

Yes that sounds the easiest option. Do you know if the truck powers up nicely once re-connected? Alarms, demobiliser, key-codes, error-codes/lights etc? I haven't looked into that aspect yet.
 
I leave my truck (an 80) for 2-3 weeks at a time without driving it now. Looked at options for isolators and decided it was easiest if I disconnect both negatives with a 10mm spanner. pull the cables out of the way and stick some rags over the terminal posts to make sure they cables don't creep back into contact. IN your case you could cable tie the cables out of the way for the boat trip to be sure of no contact.

takes me a few mins to reconnect and she fires up no problems so far with immobiliser. i started doing this as batteries were draining over the period of 10-14 days and wouldn't crank. i suspect it was a drain via the permanent live on the windows and roof.

For what its worth 17 years back i bought an 80 that had been sat on a dock in ireland not started for 18 months. popped 2 new batteries on and it fired as they always do on a quarter of a crank.
 
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Mine's a 2004 5 speed diesel. Without thinking I disconnected both earths as I was going away for 3 weeks but everything worked on connecting them up again. Only just realised there might have been a problem. Best to disconnect for safety as well.

On my 80 the siren goes off if both batteries are disconnected due to the back up batteries inside the siren. I have a key that turns off the siren but the hazards still flash.
 
I have a drain of <35ma with the car parked, locked and alarm (Toyota TVSS3B) set. I did the electric window mod last year that makes the windows permanently live and useable without the ign on and drain went up to over 130ma and was causing drain problems over several days ( turned out the batteries were on their last legs) so i undid the mod. As in Franks case, if I disconnect both batteries the alarm goes off.
 
If yours is a 8/2002 production or later, there's a short pin in the engine fuse box, for shipping purposes. IIRC it's mentioned in the Owners Manual even. Called "Short Pin A". Pulling that shorting pin will disable dome light, alarm, central/remote door lock, etc.
 
If yours is a 8/2002 production or later, there's a short pin in the engine fuse box, for shipping purposes. IIRC it's mentioned in the Owners Manual even. Called "Short Pin A". Pulling that shorting pin will disable dome light, alarm, central/remote door lock, etc.

Thanks uHu I'll look into that.....mine's a 2003/4
 
I have a drain of <35ma with the car parked, locked and alarm (Toyota TVSS3B) set. I did the electric window mod last year that makes the windows permanently live and useable without the ign on and drain went up to over 130ma and was causing drain problems over several days ( turned out the batteries were on their last legs) so i undid the mod. As in Franks case, if I disconnect both batteries the alarm goes off.

Towpack/Frank - thanks for the info on drain current. Difficult to say whether a 100 is the same as an 80 but at least I now have a ball-park figure to work with.

So if I have got my sums right then 0.035A x 24hr = 0.84Ah per day and 25.2Ahr per month. So each battery is 105Ah capacity (new) and therefore after 1 month the one linked battery would be approx. 25% discharged.

If that is correct then it doesn't sound catastrophic, but is certainly marginal. Can somebody confirm the numbers/conclusion?
 
Numbers look right.
I've left it for two weeks a few times, and it always starts like nothing right away, even in the cold winter.
 
Yep, your calculation is right. Just make sure your batteries are in tip top reliable condition.

Just thinking though, if the 100 is the same as the 80 in that it is 24v start 12v run then you would have 2x105Ah as the batteries are in parallel unless starting. So the drain would be 12.5% of the pair. Quite whether this would affect starting I wouldn't know.

As a suggestion you could always leave a jump pack or well charged battery and jump leads (or use the second battery) in it and hook it up as a boost to make sure of things before trying to start. I've never shipped a vehicle before but assuming you pick it up at the port out of the container, I would have thought flat batteries would be a common problem on arrival and collection.
 
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Somethi g I was reading on Mud - make up a test light - a 12v bulb with some wire tails - disconnect the positive on your battery and insert the light between the battery and positive cable. With EVERYTHING off if the bulb lights up, something is pulling power .... The brighter the bulb the heavier the current draw.

If two batteries, isolate them from each other first.
 
Somethi g I was reading on Mud - make up a test light - a 12v bulb with some wire tails - disconnect the positive on your battery and insert the light between the battery and positive cable. With EVERYTHING off if the bulb lights up, something is pulling power .... The brighter the bulb the heavier the current draw.
That's not the best of tests on cars with electronics. That way the electronic circuits will run at a lower voltage than designed for, which is normally not good, although I believe (hope) that the t0yota quality will suffer quite OK. Also, The electronics are "doing things" during the first (half) minute after taking the key out, and with a test bulb in the circuit (thereby lowering the voltage) they might not be able to complete those tasks. I believe you will see an amperage of 4-500 mA to start with, then going down to something small, like mentioned above here.

It's easy to use a cheap 10 £ multimeter with 10A range instead. Even better if it also has a 1 A range.
 
Yes sorry I was talking from the simplistic view of a 1HD-FT 80 series that doesn't have an awful lot of electrickery going on :)
 
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