HDJ81 24 or 12 volt?

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Beautiful, thank you very much. Was getting concerned re) DRL box, stereo, CB radio, lights... etc.

No need for concern if it was 24V. For most of us, we survive quite fine using either 24V solely or 24V and a step-down converter (or the like) to provide 12V power for other accessories.
 
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Thought I would update this post in case in the future people are searching for the answer.

Confirmed it's 12V running... keeps the batteries in parallel, then a solenoid switches them temporarily into series for 24V start. Even the winch is 12V.
 

Dave 2000

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Don't want to appear rude but why?

The switchover relay is bulletproof and removing it is probably likely to cause more potential for reliability issues than leaving it alone.

It massively improves starting at low temperatures. Earlier this year temperatures dropped close to -30C up here and my 80 was the only diesel vehicle we could get to start. Not only did it start but it fired almost instantly after sitting unused for over a week. Even at more "normal" winter temperatures it improves starting and places much less strain on the batteries.

It also makes me smile having a diesel that fires before you even hear one turn of the starter... :)

Jamie
 

Dave 2000

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Don't want to appear rude but why?

The switchover relay is bulletproof and removing it is probably likely to cause more potential for reliability issues than leaving it alone.

It massively improves starting at low temperatures. Earlier this year temperatures dropped close to -30C up here and my 80 was the only diesel vehicle we could get to start. Not only did it start but it fired almost instantly after sitting unused for over a week. Even at more "normal" winter temperatures it improves starting and places much less strain on the batteries.

It also makes me smile having a diesel that fires before you even hear one turn of the starter... :)

Jamie


First it is not a rude question; I welcome any and all comments good or bad.

To answer your post, I spend quite a lot of time visiting isolated places and often camp out over a night or more. What am I supposed to do if after three or four days the batteries are flat? We all know that one failing battery can pull down another that is wired in parallel so I have a starter needing not 12 but 24 volts, and of course no one is around (or likely to be) what now. If this same scenario happens after I have made my modification I would simply jump start myself with the second battery.

I have researched this in depth and no one has come up with a decent reason not to do it, of course I have had people defend the 24v system because it really impresses the neighbours and makes great pub talk but that’s about it, no definitive ‘that will not work’ comments. IMHO it is not needed in this day and age with the advances in battery technology and I could really use the space for a leisure battery for my fridge ect.

BTW, yes the quick 'chirp' the starter makes before the engine fires is comforting but not really an issue for me, just as long as it starts.

regards

Dave
 
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Good points. The 24v system was not really needed in the early 90's either but was probably just typical over engineering. It was only diesel cruisers sold in "cold" countries that got it anyway so you shouldn't have any issues. In your circumstances I can see the benefit of removing it if you are not planning on seeing any serious cold.

As an aside, Toyota reckon you can jump a 24 v vehicle using just one 12v vehicle. Not really sure how but its clearly stated both in the manual and on a sticker near the battery... :confused:

The only way I can see this working is to connect up the jump leads and allow both batteries to charge for a while (15 mins?). Then when the switchover relay switches from parallel to series there should hopefully be enough charge to start the vehicle. Unless the 24v starter will still start the truck when supplied with only 12v...

Guess I'll find out if I ever run the batteries down. :)

Jamie
 
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To jump your vehicle in the scenario you have given, you would find the weak battery using a voltmeter and hook up your 12V battery/vehicle parallel to that weak battery. Or just pick one if you don't have a voltmeter...


It's what I would do anyway...
 

Dave 2000

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I have tried using just 12v on my 24v starter and it just clicks, it will not crank at all. If you have two flat batteries then as you said you need to run a donor car engine and hope they (or at least one) charge up, again all this is assuming you have someone to jump start you.

regards

Dave
 
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To jump your vehicle in the scenario you have given, you would find the weak battery using a voltmeter and hook up your 12V battery/vehicle parallel to that weak battery. Or just pick one if you don't have a voltmeter...


It's what I would do anyway...
I have jumped mine in the bitter cold of winter before I replaced the Japanese batteries that came in my Cruiser. I've done it a few different ways:
  1. Hook the jumper cables from a donor car to one battery. Wait several minutes. Then crank.
  2. Hook the jumper cables to one battery. Hook a power pack (with jump start mode) to the other battery. Crank.
  3. Hook power pack to one battery. Wait 15 minutes. Move power pack to other battery. Wait 15 minutes. Crank.
Whichever of the above you are forced to do, make sure you give each battery a good charge when you get home. Some people recommend removing or disconnecting each battery to charge. I have hooked the charger up to one battery and just charged twice as long. Has always worked for me.

Those power packs with jump start mode are a worthwhile investment. You can use them to power your accessories when camping. Some have built in emergency tire inflators (or for inflating beach toys). It'll sit in the trunk all charged up and ready to give you an emergency boost if you ever need it. Has saved me a couple of times. I usually pull it out instead of the jumper cables - much easier to hook up when it's -35°C!!

Of course, I hope to not have to do any of the above this winter as I have 2 new 900 CCA batteries (as opposed to the small 500 CCA batteries I struggled with for 1.5 winters). But the power pack remains in the trunk.
 

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I have jumped mine in the bitter cold of winter before I replaced the Japanese batteries that came in my Cruiser. I've done it a few different ways:
  1. Hook the jumper cables from a donor car to one battery. Wait several minutes. Then crank.
  2. Hook the jumper cables to one battery. Hook a power pack (with jump start mode) to the other battery. Crank.
  3. Hook power pack to one battery. Wait 15 minutes. Move power pack to other battery. Wait 15 minutes. Crank.
Whichever of the above you are forced to do, make sure you give each battery a good charge when you get home. Some people recommend removing or disconnecting each battery to charge. I have hooked the charger up to one battery and just charged twice as long. Has always worked for me.

Those power packs with jump start mode are a worthwhile investment. You can use them to power your accessories when camping. Some have built in emergency tire inflators (or for inflating beach toys). It'll sit in the trunk all charged up and ready to give you an emergency boost if you ever need it. Has saved me a couple of times. I usually pull it out instead of the jumper cables - much easier to hook up when it's -35°C!!

Of course, I hope to not have to do any of the above this winter as I have 2 new 900 CCA batteries (as opposed to the small 500 CCA batteries I struggled with for 1.5 winters). But the power pack remains in the trunk.

So if both of your batteries are useless as in 'dead 'you are still up the creek without a paddle. Now you need a car AND your jumper pack. TBH I have been in the trade for a long time and have found that the average jumper pack will last about two years unless you keep it fully charged. The better ones can stand less frequent charges.

All being said if it had a 12 volt starter that would be the end of it IMHO, of course all this is speculation. I have been waiting for someone too furnish me with the 12v starter number that is used on the diesel conversions over in the states so I can put my theory to test.

regards

Dave
 
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So if both of your batteries are useless as in 'dead 'you are still up the creek without a paddle. Now you need a car AND your jumper pack.
That's not necessarily true. I have started my truck with 2 dead batteries by using a power pack only. I was at work after hours and nobody was around at all. I hooked it up to each battery for about 15 minutes and managed to get enough juice in each to start it.
 
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I've never had much luck with those power packs. Always seem too weedy to fire up any decent sized engine. Maybe I need to spend more...

Connecting up to just one battery should slowly charge both of them as they are connected in parallel. Toyota actually advise against jump starting one of the batteries and there is a cover preventing easy access to the terminals.

I guess I'd probably just tow/push start it if it came down to it. One advantage of the manual box.

Dave, I think the australian diesels were all 12v as well which might help with the part number. The OEM price for a starter might scare you though!

Jamie
 

Dave 2000

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That's not necessarily true. I have started my truck with 2 dead batteries by using a power pack only. I was at work after hours and nobody was around at all. I hooked it up to each battery for about 15 minutes and managed to get enough juice in each to start it.

Yes that could work IF and I mean IF the batteries are capable of taking the charge, a typical scenario may be that the alternator fries the batteries and they are then toast, they will not be capable of absorbing the charge, you will NOT be spinning a 24v starter with a single 12 volt source.

I've never had much luck with those power packs. Always seem too weedy to fire up any decent sized engine. Maybe I need to spend more...

Connecting up to just one battery should slowly charge both of them as they are connected in parallel. Toyota actually advise against jump starting one of the batteries and there is a cover preventing easy access to the terminals.

I guess I'd probably just tow/push start it if it came down to it. One advantage of the manual box.

Dave, I think the australian diesels were all 12v as well which might help with the part number. The OEM price for a starter might scare you though!

Jamie

You are right about the 'power packs' being a bit under powered, I opened a couple up and the battery inside is tiny 20 amp hour unit but the cranking ampa were good in the region of 200 amps. In good condition one of these will spin up a healthy engine that is good to start first or second time but will rarely crank much more than that. They are fine for cranking or even helping crank a small 4 cylinder engine but a high compression diesel 6 cylinder that is using a 24v starter and having to carry at least one flat battery and you can see these units are soon out of their depth.

As you have probably gathered I am a 'belts and braces' type of guy a sort of senoir boy scout and just like to be prepared, my 80 is indeed manual despite my liking for the auto they are just too unpredictable for someone who enjoys isolation and wilderness.

You are correct the Australians version of the diesel 80 is indeed 12v but if my research is correct then they are using the 2.4KW or 2.7kw starter, I am after the 3.0kw version but it is being a bit elusive at the moment.

At the end of the day my plan is to end up with a 12v crank and run system with a spare 12v source that is isolated automatically when the engine is off.

I have all the wiring planned out which includes a 150 amp alternator and perhaps a DC-DC charger but as always there are advantages and disadvantages.......er just a thought, we have hijacked the OP's thread......sorry. :eek:

regards

Dave
 
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If you have two dead batteries and a 12V car available, then just hook up the running car to one of the batteries and let it charge at high idle for a while. Both of the HDJ81's batteries are in parallel when not cranking, so both batteries will get a charge from one of them being hooked up to the running car.
 
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I had dead batteries when I first picked up my cruiser from the docks. Click, click... nothing. I hooked up my battery pack (cheap $50 one), waited about 4 minutes, and tried again. VROOM! Started right up.

Not saying the battery packs are everything, cause yes they are cheap... but they definitely can work. I keep mine hooked up, floating it in the garage, and put it in the back of the car/cruiser when we go on camping trips etc. It's also GREAT for blowing up my air mattress :)

PS - replaced both JDM batteries with brand new ones last week.
 

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