Outer Limits 4x4 Board

Hi i have got a diesel mq patrol, its dual battery and my aux battery has gone flat therefore i canot start my truck, i have got one of the 1200amp portable jumpstarters and do i just hook that up to the aux battery to get it going again, by the way its a 24 volt system
thanks benny

AFAIK, if you've got a 24v system, and your "auxilary" battery is flat - your stuffed. Reason: it isn't an auxilary battery - its half of your actual system. Flattening one battery is a really good way to stuff up the other good one all in one hit (the good one will equalise to the crappy one).

In your position, i would probably disconnect BOTH batteries, put them both on a charger for a day or overnight, then try to start it. You'll probly find that hooking your jumper pack onto the dead battery wont crank the motor over well enough, as the other will be half flat too.

If you have enough power to glow the plugs, you could always roll start it...

Coxy

ohhk will have to put it on a charger, the main battery is fully charged but is it safe to connect to the aux to try and start it or no?

if your primary battery is fully charged (how do you know?) then you should be able to hook your jump start pack to the flat (auxilarry) battery and start the car

however

as you now have one flat battery, and one charged one. The altenator will push current through BOTH batteries tryting to charge the flat one. This will kill your good, fully charged battery very quickly.

The only way to fix your problem, is to charge both batteries seperately, then put them back in car, and hit the starter.

any other way will just end up killing a battery, if they arent already stuffed.

Generally with a 24v sysem you will need the two for things to work "as normal". On a 24v system, if you have one good battery, and one flat battery, generally the bad battery will actually pull down the good one, leaving you with two half dead batteries.

Best bet is to either a) disconnect the leads off the dead one and recharge it; b) just stick your jump starter pack onto the dead batteries terminals and start it. Either way it should work.

Coxy

Shadow wrote:as you now have one flat battery, and one charged one. The altenator will push current through BOTH batteries tryting to charge the flat one. This will kill your good, fully charged battery very quickly.

I think this is incorrect. It will just fail to charge the weak battery.

The only way to fix your problem, is to charge both batteries seperately, then put them back in car, and hit the starter.

any other way will just end up killing a battery, if they arent already stuffed.

But this I agree with anyway. I just think it's the weak battery that will die, not the strong one.

ill tell you exactly what to do, as for some time i had a fair bit of trouble here...


firstly, to jump start you car, put you jumper leads on the PASSENGER side battery, this is the one closest to the starter motor, so the current wont have to travel as far.

2ndly, you can either drive the vehicle (or at least keep it around 1800 revs) for about 2 hours, your dead battery will charge fully (if it doesnt, its dead beyond repair. get a new one). OR you can dissconect it and charge it on a charger overnight.




the good thing about this vehicle is, once its started, it doesnt need power to run. so in theory you could take your battery out and put it onto charge while your driving about (dont larf, iv driven my mq about for a week with no batteries )

I would disconnect the flat battery, hook up the jumper pack to these terminals and try to start the car, then I would just reconnect the terminals after started. This would stop the flat battery trying to charge off the starter pack.

With these types of systems do the batteries seperate when the car is switched off? Otherwise I can't reelly see how you could have one flat and one fully charged system in when they are connected in series.

chimpboy wrote:

Shadow wrote:as you now have one flat battery, and one charged one. The altenator will push current through BOTH batteries tryting to charge the flat one. This will kill your good, fully charged battery very quickly.

I think this is incorrect. It will just fail to charge the weak battery.

The voltage regulator will want 24Volts in the system.......

seeing that one is apparently good and holding 12volts, the other "aux battery", may because of drainage have as low as 4volts showing.......
a total of 16 volts which means that the voltage regulator will continue to add charge to both batteries untill 24 volts ( its actually 28volts in a MQ system ) is shown thus charging the 'flat battery' and over charging the 'good battery'.

Whilst the flat one is getting what it needs the good one will be boil dry due to the excesive current unless its fluid level isnt watched very carefully.


Basically you over cook the good battery whilst trying to revive the not so good battery..... the end result is usually 2 dead batteries.

Kingy

Chucky wrote: With these types of systems do the batteries seperate when the car is switched off?

No.
The system is a full 24Volt system.
A 12volt 'feed' is available only for the radio.

Chucky wrote:Otherwise I can't reelly see how you could have one flat and one fully charged system in when they are connected in series.

as is often the case, ppl "add" too many 12volt appliances to one of the batteries instead of 'sharing' the load/drain.
add in a set or two of driving lights, CB &/or UHF + stereo, etc to one battery and the drawn current load becomes unequal...... forget to switch off the appliances overnight and that battery will loose enough to start the problem off.

I've seen a 12volt LPG system alone stuff one of a 24volt systems batteries it was connected to in less than 3 months of operation, when the battery was replaced the new battery lasted 4 months before it began to give trouble...... the problem was that a 12volt 'working light' was also draining from the same battery.
Once the system was equalised and both batteries had a 12 volt draw from them they lasted the 'normal lifetime'.

Kingy

Clarify one thing in your mind:

You do NOT have an "auxiliary" battery

You have a 24 volt system. Any attempt at running 12v appliances (driving lights, doof doof stereos, etc) off the "lower" battery will result in the batteries being mismatched and will result in one (the lower one) recieving the heavier charge it needs at the expense of the other (upper one) that will need to be consistantly overcharged to fulfil the requirements of the lower one.

The other option is that the lower battery never gets the charge it needs.

Very easy and quick way to kill 1 or 2 batteries.

DAMKIA wrote:Clarify one thing in your mind:

You do NOT have an "auxiliary" battery

I thought i pointed that out earlier, but i spose this will make it a bit clearer for him.

Coxy

PS. My old auto elec boss always said to me, "When sh!t goes wrong with 24volt systems, it happens twice as fast, and twice as bad".

whats the point of the 24V system then, Is it because the wires are running half the current and therfore half the heat loss? Seems pretty trivial reason for all the extra effort

If your appliances are running off 1 battery, why not just run two 12V in parallel?

Did you have to get a 24V alternator and starter too?

cruiser60series wrote:whats the point of the 24V system then, Is it because the wires are running half the current and therfore half the heat loss? Seems pretty trivial reason for all the extra effort

If your appliances are running off 1 battery, why not just run two 12V in parallel?

Did you have to get a 24V alternator and starter too?

they come like that from factory

everything is 24v

the reason is as you said, lower current for same power, means smaller wires, and less heat.

Shadow wrote:

cruiser60series wrote:whats the point of the 24V system then, Is it because the wires are running half the current and therfore half the heat loss? Seems pretty trivial reason for all the extra effort

If your appliances are running off 1 battery, why not just run two 12V in parallel?

Did you have to get a 24V alternator and starter too?

they come like that from factory

everything is 24v

the reason is as you said, lower current for same power, means smaller wires, and less heat.

Spot on. I have a 24v MQ for the farm car, and its a complete PITA cause whenever you want to use it your guaranteed that some pr!ck has "borrowed" one of the two batteries.

Coxy

coxy321 wrote:

Shadow wrote:

cruiser60series wrote:whats the point of the 24V system then, Is it because the wires are running half the current and therfore half the heat loss? Seems pretty trivial reason for all the extra effort

If your appliances are running off 1 battery, why not just run two 12V in parallel?

Did you have to get a 24V alternator and starter too?

they come like that from factory

everything is 24v

the reason is as you said, lower current for same power, means smaller wires, and less heat.

Spot on. I have a 24v MQ for the farm car, and its a complete PITA cause whenever you want to use it your guaranteed that some pr!ck has "borrowed" one of the two batteries.

Coxy

lock it?

Nah, usually its my brother or grandfather. A theif wouldn't take a second look at the truck - its a POS!! I wouldnt mind, but they either never come back, just get dumped ON the car when returned, or come back flat.

Cant choose family.

Coxy

coxy321 wrote:

DAMKIA wrote:Clarify one thing in your mind:

You do NOT have an "auxiliary" battery

I thought i pointed that out earlier, but i spose this will make it a bit clearer for him.

Coxy

PS. My old auto elec boss always said to me, "When sh!t goes wrong with 24volt systems, it happens twice as fast, and twice as bad".

He obviously needs a bit of knowledge, because the initial post states he has a dual battery system, where it really isn't in the sense of seperate starting batteries and batteries to run accessories off and also the comment about being an auxillary battery.

When you get it running again, you need to hook up a seperate battery if you're going to run a fridge or other accessory for an extended time.

Shadow wrote:

coxy321 wrote:

Spot on. I have a 24v MQ for the farm car, and its a complete PITA cause whenever you want to use it your guaranteed that some pr!ck has "borrowed" one of the two batteries.

Coxy

lock it?

ya can get under the bonnet of a locked MQ with no probs i kept my spare key in the air intake (not the engine side of the filter...) because i knew if i got locked out i could get to my spare in about 15 secs

So, to jump start one of these Patrols you'd have to use another 24v car or truck? or?

Matt N wrote:So, to jump start one of these Patrols you'd have to use another 24v car or truck? or?

nope, Just try amd jump start 1 battery and if that doesnt work try the other. Maybe charge each for 5 mins from jumper car if needed


BUt, IMHO batteries are cheap and a PITA when they dont work, GO buy 2 new ones if one is stuffed. Buy good ones and theyll last for years. a Cheap investment for going bush.

Matt N wrote:So, to jump start one of these Patrols you'd have to use another 24v car or truck? or?

2 x 12volt batteries and 2 sets of jumper leads

or

run two battery paks

or

tow or roll start it

I roll start my old MQ every day
( luckily I have a steep driveway )


All the original poster had to do was hook the battery pak up to the one dead battery.

If one batt is down you can jump just one battery on a 24v system, makes it the same as 2 good 12v in series.

Later MQ diesels (called MK by some) has a 12v system .
On these the 2nd batt is an aux batt and both are 12v.

Because on the 24v system both batts are in series any charge current runs thru both. If one is charged its internal resistance goes up (as seen by reg)and current flow drops therby the lower batt will never see a full charge.

as stated charge each batt seperately on a 24v system to get by but you will need to purchase 2 bew ones MATCHED if required.

Do not run acc off either of these batts but use an invertor or voltage dropper from a truck wrecker if you are going to run 12v light, fridges etc.

Bazzle

V8Patrol wrote:

Chucky wrote: With these types of systems do the batteries seperate when the car is switched off?

No.
The system is a full 24Volt system.
A 12volt 'feed' is available only for the radio.

Chucky wrote:Otherwise I can't reelly see how you could have one flat and one fully charged system in when they are connected in series.

as is often the case, ppl "add" too many 12volt appliances to one of the batteries instead of 'sharing' the load/drain.
add in a set or two of driving lights, CB &/or UHF + stereo, etc to one battery and the drawn current load becomes unequal...... forget to switch off the appliances overnight and that battery will loose enough to start the problem off.

I've seen a 12volt LPG system alone stuff one of a 24volt systems batteries it was connected to in less than 3 months of operation, when the battery was replaced the new battery lasted 4 months before it began to give trouble...... the problem was that a 12volt 'working light' was also draining from the same battery.
Once the system was equalised and both batteries had a 12 volt draw from them they lasted the 'normal lifetime'.

Kingy

Thanks for explaining,


I was talking to a old bloke at the pub about the old 24v patrols. He reckons when the japs were designing the patrols they asked a heap of aussies what they wanted in a 4by, and they all said duel batteries, they took this to mean 24v.

Don't know how true this is as 24v systems make alot of sense in current draw and size of motors to power, but he told a good story over a drink or two.

Chucky wrote:I was talking to a old bloke at the pub about the old 24v patrols. He reckons when the japs were designing the patrols they asked a heap of aussies what they wanted in a 4by, and they all said duel batteries, they took this to mean 24v.

Tis a true story

the Japs came here to better "understand' the "enviroment" and the "needs" of their potential customers, the MQ and LJ50 & LJ80 were built / designed mainly on what they had learned from Aussie farmers and their needs which is probably why these vehicles are so strong and reliable even after such a long period of use.
Yes the 24volt system was mainly for Aust conditions & was so that farmers could jumpstart much of the then farm machinery.... trucks, tractors, self propelled bailers, headers, etc etc were largely 24volt and remain that to this day.


The m/cycle industry was also largely based on what Australians needed back in the 70's but has now shifted to the 'American needs'.
Japan makes ALL the motorcycles that Australia needs in 2 days..... Thats EVERYTHING from minibikes to full blown road bikes and farm bikes


The rest of their production is largely for the US market ( number 1 importer) and the 'Asian' market was 2nd followed by the european market....... we are ranked way down the ladder nowdays, so our "opinion" of what a bike should have no-longer counts.

Kingy