24v vs. 12v - what are the advantages of 24 volts?

[st1age]

Ok be gentle with me...

What are the advantages to a 24volt BJ70?

What are the disadvatages?

Peter in Alberta

[maximBJ70]

12Volt - very convenient. You can use all the accesories available in the aftermarket. Parts more readily accessible. easier to boost from a dead battery.

24Volt - A significant more amount of juice for starter, lights, electrical winching, cold Canadian Winter starts.
- aftermarket products are more difficult to source, need a dc-dc converter to run stereos, cb's, coolers, etc.
- fortunately Toyota still has a good amount of 24v products so getting oem stuff isn't too big a deal, just can be pricey (but its good quality).
- need a 24v source to boost from...plus more..keep 'em coming.
- both are great and I'm happy with the 12v system and the 24v.

[brownbear]

24 volts use half the amps for same wattage.

example, 100 watt lamp uses 8.3 amps in a 12 volt application

in a 24 volt one it is 4.15 amps.

Volts x amps = watts, or watts divide by volts equal amps

So if you have a stock 55 amp alternator the 24 volt one can do more.

Easier to upgrade headlights, as the harness may not need replacing for heavier duty wires....etc.

[kim]

" need a 24v source to boost from."

This isn't necessariy true. I've jumped my from a 12V battery pack connected to a single battery.

Is there any potential to harm my system doing this?

[brownbear]

Originally Posted by kim

" need a 24v source to boost from."

This isn't necessariy true. I've jumped my from a 12V battery pack connected to a single battery.

Is there any potential to harm my system doing this?

You can boost from a 12 volt battery.

BUT you have to hook it up in parallel to one battery.

So I will try to illustrate with words....

In a 24 volt system, with 2 batteries. You first battery is negative to ground, then the positive goes to the negative in the second battery. Then the positive in the second battery provides the 24 connection to the vehicle.

SO to boost to it, I would Hook the positive jumper cable to the positive battery post on the first battery. And the ground(negative) cable to the engine block on the dead vehicle or negative post on the first battery.


This should assist in boosting. Since it is not perfect it only jumps up your voltage a bit, but not all the way to 24. As it would give 14 or so to the first battery and then what ever is left in the second would be the total voltage.


In turn you can boost other people by cranking off on the first battery. Just connect the positive jumper to the positive on the first battery and the negative jumper on the negative post on the first battery. Take your meter set for volts it should read 12-14.

Then hook this up to the dead vehicle.

The harm it may cause is(boosting off one battery) is you drain the one battery more than the other. So when the recharge the second battery is going to get overcharged and low battery not enough. A 12 volt tap puts a lot stress on the batteries. Once the batteries get out of sync enough you have to replace both. As the batteries must be replaced in Pairs.

But to get a boost, chances are you are dead anyhow, it will get you going. Best bet would be to get a battery charger and charge each battery independently to equal them up. But with all the post connections off.

Now this is all theory in my head eh.... so it's worth the time it took to write.

[denis]

http://forum.ih8mud.com/diesel-tech-24-volts-systems/124529-24v-advantages.html

[kim]

"SO to boost to it, I would Hook the positive jumper cable to the positive battery post on the first battery. And the ground(negative) cable to the engine block on the dead vehicle or negative post on the first battery."

This is exactly the procedure I follow when I connect my battery pack. I spent some time thinking about it as well and spent a fair amount of time checking voltages all along the chain to make sure I wasn't fuc., er, making a mistake.

Thanks for you time, Brownbear.

[brownbear]

Originally Posted by kim

"SO to boost to it, I would Hook the positive jumper cable to the positive battery post on the first battery. And the ground(negative) cable to the engine block on the dead vehicle or negative post on the first battery."

This is exactly the procedure I follow when I connect my battery pack. I spent some time thinking about it as well and spent a fair amount of time checking voltages all along the chain to make sure I wasn't fuc., er, making a mistake.

Thanks for you time, Brownbear.

That sounds right... This guy George has a pretty good explaination... little bit on a side note. Denis posted the link, I liked the info.. see below VV

Originally Posted by george_tlc

Yes, 24V on paper should be better from a current consumption point of view. In reality 24V has caused me more problems than it's worth and that's PRACTICAL experience IN THE BUSH. And I am an EE.

The issue is if one battery goes 'weak', and that HAS happened to me, the 24V system will NOT start. The weak battery just dies rapidly and does not allow the starter to crank fast enough, glow plugs to heat and/or fuel cutoff motor to function. Yes, we can talk about 'well maintained' till the cows come in, but batteries DO die overnight.

Once one battery goes 'weak' a 24V system cannot charge it back up, you will find the 'good' battery overshadows the 'weak' one. The alternator just cannot get the 2 batteries balanced. The only way to correct the situation is to take a 12V charger and get the 'weak' one topped back up again.

I know that I've had one good battery and the second one has gone 'weak' and it is impossible to crank the engine over to the point of starting it.

After converting my 4wd to 12V I started it on one weak 45a/hr 12V battery. It cranked slower than I've ever had my 24V system try to crank and after a couple of attempts it started. I've NEVER been able to start the same vehicle at that speed with the 24V setup. I'm guessing that either the 24V glow plugs or the 24V fuel cutoff motor just couldn't do the job when presented with one good and one weak battery.

Either way, the 24V system is just a pain in the rear that I don't have to face anymore. Nissan & Toyota went away from 24V systems to 12V systems for a good reason. The reason automakers are looking at going to 36V or higher are for all the b/s accessories that new vehicles are getting buried under - power seats/seat heaters/ECU's in every gadget, power windows, sunroof motors, media systems etc etc etc.

Simple question to folk that think 24V is as or more reliable - have you heard of folk with dual 12V batteries not being able to get going under their own steam with A flat battery AND have you heard of folk with 24V vehicles not being able to start under their own steam with A flat battery?

Wiring - I converted my 4wd to 12V from 24V and I had access to the wiring harness of the 12V vehicle and the wire gauge was the same for both. Yes, 24V has nominally 1/2 the current, but that's really only an issue with a couple of cables - starter motor, headlights and winch. The rest of the wire's only carry a couple or so amps.

Finally, I doubt we'll come to an agreement which is better. I'll just say I spent 10 FULL days converting mine from 24V to 12V and felt I had a much more dependable vehicle when done (from a starting perspective).

I've driven many tracks and non-tracks in the oz bush (1000's of miles) in a lone vehicle and I was never stranded due to the 24V system. When I was a lone vehicle I was VERY conservative about battery condition etc - but each time I started the vehicle I was VERY conscious of how fast it cranked over. I knew IF the engine fired over, the diesel reliablity would get me home. It was the "IF" part that always was a worry....

cheers,
george.

[roscoFJ73]

Anyone know if Toyota are still producing 24v models?

[brownbear]

Listening to the problems with the first battery and dual batteries issues on a 24 volt system, I would be tempted to install a single battery from an aircraft.

The 24 volt battery I install in the plane I look after is huge and would work for years in a truck. They retail for 1600.00 canadian. So a bit of money. But if you get 10 years plus out of it, then your ahead of the game.

If someone wants to drive to Northern BC I will give you a free used one...... Lots of power left. Just was slow starting my dual 750 hp engines

[kim]

1600 bucks for ten years sounds expensive to me. 160 dollars a year can buy you 2 new batteries, every single year.

[Greg_B]

Let me preface this by saying opinions are like assholes...yada yada...so I'll thrown mine in the ring too...

1st, I liked the way the st1age posed his question...a matter of advantages and disadvantages. This thread has stayed on that track for the most part.

Much better then which is best, because as george has said...24V is better. But then again, 36V is even better yet! Remember the 6V VW's?

I am also confused that george says his system has been nothing but trouble, but then at the very end says it has never stranded him in the bush.

If he choose to convert his 24V vehicle to 12V (10 days work) due to his preception of the advantages of 12V...great! There are many valid points and 12V does have some advantages. It may be a worthwhile endevour for some.

Yes, there are disadvantages to 24V. It is not a common vehicle operating voltage. Having one battery go bad will stop you from using the starter. In effect, both batteries are one. Parts can be harder to source (but in this day of a shrinking world less an issue if you are plugged in). It is best that one mind the battery system...or install a load balancer...or switch batteries from side to side every oil change. Spares on the shelf are always a good idea, when you can; Gives time to source someone who can rebuild 24V stuff. In this day of solar panels, charge controllers, deep cycle batteries and such...one best not go into the deep bush alone without some sort of backup; no matter 12V or 24V. And, one best understand the two battery system for jumps (to and from) etc. Certainly not as plug and play as a 12V system, but then if we all wanted plug and play we would not have older Landcruisers with mechanical systems.

Again, as someone said...24V is better...there is no argument. Less pressure (amps) needed to do the work, or something like that.

Just because in vehicle application 12V is more common then 24V does not mean that 12V is better. Remember VHS vs Betamax?

What was the question again?

gb

[Deny]

I have an extra plus to add on to all other assho.....er I mean opinions. All other points have been well said, but the 24 volt 8274 winch is the ultimate.
That's all I got to say.
Cheers,
Deny

[denis]

Somehow 12V is KISS and 24V is MIBS. As far as I'm concerned I would favor a dual KISS

[lowenbrau]

I'm a 24v fan but it’s mostly out of habit. In the days of simple rigs like BJ42s there was very little by way of electrics. The batteries did the starting and winching and threw some light on things when required. 24V kicked ass for that, especially if the headlights were 24 volts. No stereo, no laptop, no cell phone charger. Just a super reliable truck.

These days, I'm filling my rig with electronics, Satellite radio, GPS, computer, DVD player, fridge/freezer, auxiliary lighting everywhere, Webasto, extra heater fan etc etc etc. I'm having to design a completely separate power system for the accessories. It surely would have been much easier for me to have started with a 12V truck.

[brownbear]

If I was to have a 24 volt vehicle.....IMOP.. cause I too like electric goodies. I would install a second alternator, A big ass 12 volt one. Make an independent busbar for it. Use a deep cycle battery(as it is not there for starting, just play) And I would use a two wire system. No ground to chassis, ground to battery. I would not even let the electrons go to ground, only the negative side.

Remember electrons actually flow negative to positive. Conventional theory is just for simple understanding, and cause all the diagrams are written that way.

I even have thought of installing a 3rd battery to my 12 volt cruiser. It would charge on demand thru a solar charger, when I flicked the switch.

Then at night I could run light, dvd's for kids, music and more. With out the fear of not starting. When the battery was dead it is bedtime.

[kim]

Originally Posted by brownbear

If I was to have a 24 volt vehicle.....IMOP.. cause I too like electric goodies. I would install a second alternator, A big ass 12 volt one. Make an independent busbar for it. Use a deep cycle battery(as it is not there for starting, just play) And I would use a two wire system. No ground to chassis, ground to battery. I would not even let the electrons go to ground, only the negative side.

Remember electrons actually flow negative to positive. Conventional theory is just for simple understanding, and cause all the diagrams are written that way.

I even have thought of installing a 3rd battery to my 12 volt cruiser. It would charge on demand thru a solar charger, when I flicked the switch.

Then at night I could run light, dvd's for kids, music and more. With out the fear of not starting. When the battery was dead it is bedtime.

I like it!

I've considered the same thing but I never considered your wiring idea and saving all the juice.

[Lantec]

Originally Posted by brownbear

If I was to have a 24 volt vehicle.....IMOP.. cause I too like electric goodies. I would install a second alternator, A big ass 12 volt one. Make an independent busbar for it. Use a deep cycle battery(as it is not there for starting, just play) And I would use a two wire system. No ground to chassis, ground to battery. I would not even let the electrons go to ground, only the negative side.

Remember electrons actually flow negative to positive. Conventional theory is just for simple understanding, and cause all the diagrams are written that way.

I even have thought of installing a 3rd battery to my 12 volt cruiser. It would charge on demand thru a solar charger, when I flicked the switch.

Then at night I could run light, dvd's for kids, music and more. With out the fear of not starting. When the battery was dead it is bedtime.

That idea sounds awesome! Imagine the possibilities!!

[Deny]

I run the 3 battery system in my BJ42. 24v everything, then through a converter to a 12V gell battery in back which is isolated, and I can run my radio, axiliary lights till they die when camping, then start up in the morning with no problems. When I get my 12 volt truck running, will do the same thing, minus the converter, and will run a wabasto off the isolated battery too.
Cheers,
Deny

[brownbear]

That sounds good deny,
So your 24 goes thru a converter to charge the 12 volt battery? Is it a charge converter? I was thinking of using a 12 charger designed for solar panels.....kinda like this one

http://www.canadiantire.ca/browse/pr...=1175027874894

But I am not sure if this would work. I thought I could take 12 volts from the truck system, run it thru this charge controller and then it would recharge till full then stop.

That way I would not have to isolate the batteries, and have my alternator only charging the 3rd battery. I would still though have a switch so I could turn this on when I wanted.

[lowenbrau]

Yeah, just when I don't need it anymore, look what I found...

24vDC to 120VAC inverter. 900W ---- 90bux!

[lowenbrau]

Originally Posted by brownbear

That sounds good deny,
So your 24 goes thru a converter to charge the 12 volt battery? Is it a charge converter? I was thinking of using a 12 charger designed for solar panels.....kinda like this one

http://www.canadiantire.ca/browse/pr...=1175027874894

But I am not sure if this would work. I thought I could take 12 volts from the truck system, run it thru this charge controller and then it would recharge till full then stop.

That way I would not have to isolate the batteries, and have my alternator only charging the 3rd battery. I would still though have a switch so I could turn this on when I wanted.

Since we're talking about a 12V rig in this case...
Why not just run a the third battery through a relay that is closed only when your ignition is in the run position. You charge when you are driving and then kill the accessory battery when you're camping. Truck starts in the moring as usual. Side benefit is that your accessory battery can help start the rig if you leave the lights on at the mall.