12 and 24 volt

[camo388]

I have a question for those that have more electrical experience than me.
My Lightweight is all 24 volt and I have a 24 volt winch to go with it.  I am replacing the 2.25 gas engine with a 2.5NA diesel and have a problem sorting the electrics.
The 2.5 NA has a 12 volt starter and needs 12 volt for fuel solenoid.  So my thinking was to change everything to 12 volt and carry on.  It become unglued when I wish to use the winch as a 12 volt motor is more expensive than a new 8,000 lbs Smittybuilt for sale at local Bumper to Bumper.  Over $800 for the motor! :o
So basically can I stay with 24 volt and take power from one battery for starter and solenoid without drawing down that battery too much?  I have a 24 to 12 volt converter but it is low amp meant for radios or charging laptops etc.  So I could use this for solenoid and trust starting off one battery will not be a huge drain for a couple seconds of use.  Or is there another way of doing this without getting too complicated or expensive.  If I knew there was a 24 volt starter for the 2.5 NA, I'd be laughing but I don't think there is.  And probably mega $$ to boot. :o :o
I could go both systems 12 and 24 as I have alternators to suit and 2.5 NA military FFR's were set up for 12 volt truck and 24 volt for radios.  Going that way I could probably get away with lower Amp batteries as there will be low load on either system.
Any advice??

Bruce

[B-Red]

Good question Bruce.
Your lightweight 24 volt loads are:
Lights. Winch.
Your engine 12 volt loads are:
Fuel pump. Starter.

Your new alternator should be 12 volt.

Your wiring should be as follows:
Connect the two batteries to the alternator using an isolator in parallel. This will top up your batteries without compromise.
Your chassie ground is now 12 volt so you can operate the engine starter and fuel pump.
Need to set up a secondary ground strip for the lights and the winch for the 24 volt setup. Otherwise, your light bulbs will need replacement to 12 volt. Wiring to lights has to checked closely so it does not overload too.
It can be done. You have to label it closely so you don't mix voltages.

[headdamage]

It is not quite that easy.... instruments are also 24V.

I would either do a complete conversion to 12V or I would keep the truck 24V and run a line off of the grounded one of the two batteries to get 12V to the starter.

12+12=24 take a line from the positive of the batt that has it's neg going to ground and that will provide 12V to that line. The batts remain in series for 24V and all other circuits still have 24V. The down side is this might lead to uneven wear on the batts and you may have to replace one or both of them more often than might be expected.

This might help:

[Red90]

That's what I would do.  No point in making life difficult.  I don't think it will affect battery life to any extent.  Maybe swap the batteries every year or two to even the usage out, but it is probably overkill.  Having a smart charger is probably the best thing you can do as it brings the batteries to a voltage high enough to equalize the cells.

[camo388]

Thank you for your replies and the diagram is wonderful and in color to boot.  Where is that smiley face with 2 thumbs up?
I have no excuse if I get battery hook up wrong.  ;D

I could do total conversion to 12 volt and it may not get too expensive until I want to have a winch.
Keeping all 24 and take 12 v for starter sounds way easier.  I can easily swap batteries on a regular basis to keep them equal.

[camo388]

Now I have had advice from someone that has taken 12 V from a 24 V system and says it will kill the one battery.  I don't know what the draw on the 12 V was, heater motor or winch??  His recommendation is to get a 12 / 24 V Series Parallel switch which is sometimes used in heavy trucks when everything is 12 V but the starter is 24 V.
The switch changes a 2 battery 12 V system to 24 V for the starter.  This sounds like it would work until I wonder if the switch will take operating a winch that will run longer and maybe harder than a starter.  Anyone had experience with 12 / 24 V Series Parallel switches??

Thanks for any information,  Bruce

[Red90]

In your case, using the one battery for only the starter, you should be fine.  If you were drawing loads all of the time, it would cause trouble.

Like I said earlier, if you want to be safe, get a smart battery charger. With the truck only being used, I assume, intermittently it is the best thing you can do to keep the batteries healthy.  I'm over 10 years on the batteries in my truck and they are still as healthy as when they were new.
https://www.amazon.ca/NOCO-G7200-7-2-Amp-Battery-Maintainer/dp/B004LWTHP2/ref=sr_1_1?s=automotive&ie=UTF8&qid=1472756592&sr=1-1&keywords=24%2Bvolt%2Bbattery%2Bcharger

You can do the parallel/series switching, but I would see it as unneeded complication and cost.  https://www.amazon.ca/PARALLEL-SWITCH-DOUBLE-1119845-3603872RX/dp/B009VKJ6MI

[camo388]

AAAHH!!   Decisions Decisions

Life would be a whole lot easier if I changed all of the vehicle to 12 V and left the 24 V winch at home. 
I'd have to learn to drive avoiding any sticky situations. ;D and/ or pack a hand winch. LOL
Going all 12 V would also mean I could tow my Sankey with an other 12 V vehicle fitted with a pintle hitch.

I had tried to keep this 12/ 24 V problem simple but the more I think about the more I realize it isn't just that simple.  Getting past the truck being 24 V, I then think about   wanting to tow a Sankey and this adds another kink.  I'd have to dedicate 1 Sankey to this vehicle which is fine as long as I am moving dirt, wood etc but I also want to have a 2nd Sankey set up for camping.  If 2nd Sankey also 24 V then I'm stuck pulling the Sankeys with just the one vehicle.   
If I go that way then I've just shot myself in the foot. :o

[Red90]

On sale this week.

NOCO Genius G7200 Smart Battery Charger. $113
http://www.canadiantire.ca/en/pdp/noco-genius-g7200-smart-battery-charger-0111928p.html#srp

[B-Red]

I have the next size up to charge two batteries. One side of it failed two weeks ago. Have it on Tigger all the time.

On another note, Ian mentioned that they sell 12-24 volt DC transformers for use with radio equipment. Can be handy for 24Vdc cars.

[Red90]

Not for this case. He needs the 24v for the starter. A 400 amp transformer would be a bit too big.