Duel battery conundrum.....

Matt Vee Jul 23, 2019

  1. Matt Vee

    Matt Vee Active Member

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    Ok so here are some pics of the duel batteries in my truck. At first I thought it was for 24v start but I took one battery out and it started just fine. Any ideas what's going on here?
    Thanks:

    DSCF2059.JPG DSCF2058.JPG
     
  2. Matt Vee

    Matt Vee Active Member

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    I'm having trouble with uploading pics, please bare with me
     
  3. Matt Vee

    Matt Vee Active Member

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    try this one

    DSCF2054.JPG
     
  4. MarkW

    MarkW Well-Known Member I am in morocco

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    12v start on Colorados
     
  5. Higgy

    Higgy Well-Known Member Supporter I am in denmark

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    I think Technically it was something to do with Toyota introducing What they called a winter Pack, For better cold cranking in countries with extreme Low Temps... I think on Cranking, power is taken more from one Battery as Opposed to equal power from Both So one is the cranking Battery and then jointly for electrics, aux power etc... Oh! i dont Know. I thought i was doing Well:wtf:
     
  6. Beau

    Beau Well-Known Member I am in guyana

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    Yup, 12volt system. Both connected in parallel so increased your amps, but keeps the Volts the same.

    hmm not really sure if I would call it a designated cranking battery due to them being in parallel but I do think the starter draws more "Juice" from the passenger side one vs drivers side. Both batteries would level off relatively quickly afterwards though.

    @StarCruiser can chime in on that ^ Our Forums Electrical Expert :wink:
     
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  7. Matt Vee

    Matt Vee Active Member

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    So that is the conundrum resolved then, thanks dude :)

    Next question, does this set up mean I can chuck a bunch of lights and accessories on without putting in a dedicated accessory battery and charger for said battery? or do I need to put a third battery in.
    I need to run a bunch of lights, compressor and a winch.
     
  8. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    I’m a bit late to the party I see Matt.

    Higgy has pretty much got it. The Collie could start quite happily in one battery but (and this is pretty much theory as it’s unlikely) if it took a lot of cranking to start, there would be less reserve available. In other words if you left your lights on and with two batteries it lasted say 2 hours, it would probably last 1 hour before the lights went out.

    As for one battery being used for starting it would depend how it’s all wired but broadly speaking I would say both batteries are going to supply starting current in almost equal measure. ‘Almost’ due to internal battery resistance, clamp resistance and cable resistance plus points of connection of the starter cable and earth. The difference will be small but it will be there.

    Can it start on one battery? Yup. If you wanted to, you could remove the second battery, alter the wiring to include a split charge relay or better still a DCDC charger and have the second battery as a leisure (deep discharge) battery that won’t discharge your starter battery with all those lights etc.

    Again, you don’t have to add a leisure battery setup, but doing so separates your ‘house loads’ from your vehicle loads and starting. The advantages of this are that you can use a deep discharge (leisure) battery which is designed to take a greater discharge than a starter battery plus if you do discharge it, you’re not relying on it to start the truck.

    You don’t need a third battery. Ideally uprate the battery you intend as your starter battery to the biggest Ah and CCA rating you can physically fit in the space, then use the space the other battery occupied for as large a leisure battery you can fit in there and feed one from the other via a charging system of your choice. No reason not to use a split charge relay like the Durite as it’s so close and under the bonnet, with a lead acid standard construction (vented) battery.

    Winch use would benefit from a solenoid linking the two batteries to work as one when winching. Whether to draw from your leisure battery or the main starter batter has many answers, most or them will be right as there are pros and cons to each. Just consider that generally, winching is infrequent but performed with engine running to charge the system and generally power the winch.
     
    Higgy likes this.
  9. MarkW

    MarkW Well-Known Member I am in morocco

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    One thing which always baffles me on the Colorado is that it will start off 1 battery, if its the drivers side battery connected but not if its only the passenger side.

    Starter is on the passenger side and the cable goes up to the PS battery then across to DS and then the fusebox. The connection between Starter and Fuesbox is essentially continuous, so disconnecting a battery doesn't disconnect the electrical circuit.
     
  10. Matt Vee

    Matt Vee Active Member

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    I actually disconnected the drivers side battery tbh and it started.
    All this came about when it wouldn't start one morning so I took a look under the bonnet and the drivers side battery was goosed, covered in crystals and generally not well, wouldn't accept charge or anything, wouldn't start on one battery (passenger side). So I got another battery put it in turned the key and hoorah, it started.
    That was about a year ago. Got drove around for about 3k miles in that year so I thought hey I better check that battery still has charge (suspecting the lack of BCDC/DCDC was the cause of the previous ones failure and lo and behold it was full to the brim of electrical joy, so chucked it back on and start thinking about seriously finding out what exactly is going on with it before I chuck a winch on it.
     
  11. Matt Vee

    Matt Vee Active Member

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    Thanks man, read that a few times, think I took it all in.
     
  12. Chris

    Chris Super Moderator Supporter I am in europe

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    The ridiculous thing is that the Winter pack was largely only fitted to UK vehicles. Brrrr, damn those warm wet winters. And they didn't fit it to the short wheelbase. Just a nonsense. What no one has covered as far as I can see is that the dual battery set up suffers from a bit of an Achilles heel and that is that when one battery starts to fail due to age it then acts as a resistor in effect and drags the other one with it. So it will start with a single 12v battery no problem at all unless it's connected to a second duff 12v battery.

    Incidentally along with the Winter pack, UK vehicles were again largely the only ones fitted with rear lockers. Well how else you going to get the 1/3 mile to Tesco in November?
     
    Beau likes this.
  13. Matt Vee

    Matt Vee Active Member

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    lol, for real, don't think I have had to use the Rear locker once yet, hardly ever had to put it in low ratios either. Weird little truck it is. Had an all singing all dancing much newer Shogun before this,which don't get me wrong was a cool mobeel but this little chugger just keeps on trucking through whatever.
     
    GeekOKent likes this.
  14. AdventureWagon

    AdventureWagon New Member I am in australia

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    Is this an upgrade? My 90 (a Prado) doesn't have a dual battery. Previous owner had one at some stage which looks like a seperate 12v system charged during vehicle operation but usable for camping, winch, etc without gear of draining the starter battery.

    I'm guessing in an emergency you could link the two to use the auxiliary battery to jumpstart.

    Want to get a dual battery back into mine at some stage mainly for camping purposes.
     
  15. Chris

    Chris Super Moderator Supporter I am in europe

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    No not really an upgrade. It was just the spec for the majority of UK Colorados. But not all. There's really no benefit to the system at all. Just more weight and complication. Batteries in parallel really need to be as close to identical as possible. Even identical batteries will have some variances. Quite often on the dual set up one battery will fail and be replaced with just whatever is to hand. Or both get replaced at additional cost to keep them paired. It's a handy place to stick a leisure battery though via a separate charging system as Rich said.
     
  16. Matt Vee

    Matt Vee Active Member

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    Chris that is exactly what I am thinking.

    I'll have to work out how to separate the two as they both have fairly heavy wires coming off them going to somewhere that needs some heavier level of juice, relatively speaking.
     
  17. Chris

    Chris Super Moderator Supporter I am in europe

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    Easy to do Matt.
     
  18. Matt Vee

    Matt Vee Active Member

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    Cool, could you expand on how if it's cool with you :)
     
  19. Chris

    Chris Super Moderator Supporter I am in europe

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    Well I don't have a Collie anymore Matt, but in principle, it's a case of disconnecting anything on the aux battery (the one that doesn't get fed directly from the alternator at a guess) and reconnecting all of that to the main battery. You can then come from the main battery afresh with cabling to a split charge or more preferably a DC2DC charger like a Mastervolt, Redarc or CTEK onto your spare battery. I don't know what connections other than earth and positive there are on the Winter Pack aux battery. It might be there's only those two. But if there are some vehicle system supplies like lights and fuses then a simple re-route onto a decent junction block might be the simplest. I had a SWB Collie and I actually added a second battery in there via a IBS battery split charger. If it's for leisure, I'd strongly recommend installing a specific leisure type battery that can cope with your needs such as a fridge etc. Don't just use the old car battery. But this is where it starts to ramp up in costs. An alternator can only supply one current at a time and two separate batteries will require different charging regimes. An alternator will only see one 'averaged battery and won't serve either of them sufficiently well. So a DC2DC system (search on here) effectively hides the second battery from the alternator and gives it a completely separate charging pattern according to its needs.
     
  20. Matt Vee

    Matt Vee Active Member

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    cool, thanks :) do you happen to know which side is the normally installed battery and which is the extra?
     
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