Convert to 12 volt or use a power inverter?

[steelandcanvas]

715, Since you don't know what your loads will be, I would say the 12 Volt alternator would be the way to go. Much more current available for your add-ons. Your AC will probably require 20-30 Amps itself, I'm not real sure what they draw. I hope I've been helpful and not confused you too much.

 

[Lonesome715]

In a lot of ways I can see how that would be the better choice. But if one inverter would do it all with out having to install a third battery , wing harness, and alternator I like it better.

 

[steelandcanvas]

I have a third battery in mine for the 12v system.

I think it would be required for a seperate 12 VDC system.

 

[Lonesome715]

715, Since you don't know what your loads will be, I would say the 12 Volt alternator would be the way to go. Much more current available for your add-ons. Your AC will probably require 20-30 Amps itself, I'm not real sure what they draw. I hope I've been helpful and not confused you too much.

We were typing at the same time. No man, just the opposite. I am learning a lot from this thread. I see it will not be as simple as I had though. So I will have to plan very carefuly and make sure I have room to ad on later.

 

[Recovry4x4]

If your amperage requirements are 35A or less, the absolute easiest and cheapest way is with the inverters Headwizard linked. Literally 2 wires in and 2 wires out and you are set. Do you ever plan to ford your deuce or is it a get out of Dodge quick truck? If so the alternator kits with the aftermarket alts are not waterproof. With that said, I'd bet that your truck has an alternator, not a generator. If it has a big piece of conduit going to it, its a genny, if it has a few smaller wires, it's an alt. Need to define your needs before you shop for your solution.

 

[Lonesome715]

That is interesting. I just assumed all of them had generators. I do not plan to take this truck through deep water. But then again we never really know where we will end up until we are there. So short answer, no I do not plan to ford this truck. I do want it to perfomr in a large varity of enviroments and tasks though.

 

[zout]

I have my generator - main chore is charge the batteries when shoreline is not available and want to run everything EXCEPT the ac off the batteries - do no run ac from battery power only - it will kill the deep cycle's in a hurry.

The recharge from the gen is bringing the batteries back up to run everything else (all lights are led 12v - frig's are 12v) hot water heater is 120v along with the ac - these are set aside to not run off battery stored power.

I can run ac and recharge batteries and an outlet or 2 depending on amperage - but that is what it is designed to do.

Getting a headache yet

 

[Lonesome715]

Um, yep. That did it.

 

[jimm1009]

Just to clarify, the two separate alternators, 1 each 24 and 1 each add-on 12 are completely seperate electrical systems.
The 24 volt system would be the OEM system tied into all the OEM electrical components with the two 12 volts batteries below in the OEM battery compartment.
The add-on 12 volt alternator will need a 12 volt battery (battery #3) to take the charge and distribute 12 volt power from that 3rd battery.
All wiring including the 2nd master switch, fuses (or circuit breakers), etc. is separate and the 12 volt consumers should have seperate isolated grounds returning to the 3rd battery.
My unsolicited opinion is that your additional equipment that runs on 12 volts only would be best supported by the add-on 12 volt alternator.
There is a member here on S.S. that has a really neat 12 volt (approx 165 amp) GM based alternator that will go above the OEM 24 volt alternator or generator or above his 24 volt GM based alternator either way.
You will need larger diameter alternator belts to include the 12 volt add-on unit into the drive loop but that is the only engine modification other than the obvious addition of the actual 2nd alternator.
Two seperate isolated systems is what you will have that way but it is really easy to install if you take your time and be careful in your installation you will have years of uninterupted service from it..
Most people with the add-on 12 volt system install the 3rd battery under the passenger bench seat (or so I am told). It sounds to me in reading your thoughts on added equipment that you may be approaching 50 amps + in a continuous draw in the summer with A/C on.
As suggested by others, sit down, draw it out both ways and then pencil in the component costs and do what is best for your needs.
My thinking is that you will choose the add-on 12 volt system but it is your truck and your buget. Just make sure that you protect wires and cables running through the firewall, floor, and any other sheetmetal containers, etc.
Big cables can go to a dead short and start fires faster than you can get pulled over in certain driving conditions. SAFETY above all else can be had with either system as lone as one crosses their "T's" and dots their "I's" by protecting the wire harness.
You will be able to get all of your questions and concerns answered here on S.S. if you ask away. There are some very helpful guys and gals here to assist if needed.
The 12 volt add-on system IS in my future for my M35A2C but has not been passed by the bidget committee to date.
I would not tap off one of the OEM batteries for more than a cell phone charger as an imbalance can kill your very expensive military batteries. but that is my 1.7 cents worth.
I am curious what you do decide to install and would like to know how it comes out if you will share with the group.
Regards, jimm1009
PS: You can also use a select group of 110 volt appliances if you step up to an inverter or 12 volt DC appliances are avaialbe to some degree too in the RV community.

 

[Recovry4x4]

The 12 volt add-on system IS in my future for my M35A2C but has not been passed by the budget committee to date.
.

You have a budget committee? I have to procure my operational funding from the War Dept!

 

[steelandcanvas]

I have my generator - main chore is charge the batteries when shoreline is not available and want to run everything EXCEPT the ac off the batteries - do no run ac from battery power only - it will kill the deep cycle's in a hurry.

The recharge from the gen is bringing the batteries back up to run everything else (all lights are led 12v - frig's are 12v) hot water heater is 120v along with the ac - these are set aside to not run off battery stored power.

I can run ac and recharge batteries and an outlet or 2 depending on amperage - but that is what it is designed to do.

Getting a headache yet

We were discussing 12 and 24 Volt alternators and generators that were being driven by the vehicle's engine. Not a seperate genset like you are referring to. Sounds as though you were giving examples of a motorhome or camper system.

 

[Lonesome715]

Now that was informative, thanks. From my limited knowledge I am leaning towards adding a 12v. I think biulding the wireing harness will be time consuming but not all that complicated.

 

[jimm1009]

Kenny,

"My committee" is self-proclaimed (& self-awarded) by the same women who sometimes thinks that she is my mother too for the last 30 years or so.
Not that "she" is correct on either count but that is her opinion.

My philosophy usually is "easier to beg for forgiveness than ask for permission"

Back on point...
I had a thought, and it is to help anyone decide on the same similar situation fo their truck. Perform your Electrical Load Analysis by doing the following;
On paper take all the currently installed electrical consumers and make two columns. One is for continuous draw items and one is for intermittant draw items. The starter does not count as it is not used very often in most situations. Convert all your items into amperage consumed. All your 24 volt items will double their amperage requirements when converted to 12 volt units. When you have totaled up your currently installed items go to your items that are going to be added on such as your A/C System. Add up all these continuous draw items and the newly installed intermittent items. Then add both totals together. Your generator or alternator should be able to handle the total continuous requirements at 80% of it's capacity. The other 20% is for the intermittent draw items such as the horn and brake lights as two examples.

Jimm1009

 

[Parker2]

What kind of cost did you encounter? And where did you get the starter? What if any bad points have you noticed?

I have had absolutely no bad points at all. The truck would even start with the 24 volt starter, but it didnt like it. It was like the battery was real low.
As for the cost of the starter. I dont really remember, but I would imagine it was a couple of hundred bucks ( I bought it a few years ago). I got the starter from a localy owned parts store that deals with heavy trucks and equipment. They had it in stock so I don't think it's a hard to find starter.

 

[Hunter2506]

Close, but here's the actual: 55 X 2 = 110 / 12 = 9.16 Amps

I know how to do the math. I also know what the real wrold draw is with an amp clamp on the wires. Trust me, two 55w rated aftermarket lights don't draw 9.16 amps, not even when the system is charging at 13.6-14.2v.

To the OP-

It sounds like you're planning on running alot more 12v stuff than I am. I think others are right in telling you that a dedicated 12v battery and alternator is the best bet. Very easy to do. GM one-wire (65, 80 or even 100 amp units) with a single 4 or 6 AWG wire to the battery positive terminal, then from there, your fuse block. You can still use a chassis ground.

 

[Lonesome715]

By the way Hunter, that is a awsome photograph in your avatar. I am starting to really agree that a 12V system is the way to go. However, I am still on the fence on whether or not I should convert the whole truck to 12V or just add a 12V system.

Parker I am from Seffner. So I might know the shop you are referring to. Are they still around?

 

[Ferroequinologist]

One thing about keeping the truck 24v- If a part dies, easy to get a take off or straight from a surplus dealer. If you convert everything, you would have to find those specific parts, keep the numbers handy, etc.

 

[Lonesome715]

Very true. I have been through that beofre and I do not like it. I also like the fact that the stock 24V system will continue to work and get me home if the 12V system fails.

 

[Stan Leschert]

I would highly NOT recommend converting the entire truck to 12V. I have seen this happen too many times before, and when something goes wrong, only the guy who did the conversion, knows what exactly was done. Usually all of the 12V crap gets ripped out and the truck either gets restored to 24V or just scrapped!

Of the 2 options, while an invertor is a good solution for low loads, the seperate 12V alternator and spare battery is by far the best way to go. A 1 wire GM alternator from the local wrecking yard won't cost much. Then you have to build a bracket, get new belts, and wire it to your new battery. Not that hard to do!

 

[Lonesome715]

You know what man. I think that pushed me the rest of the way over. I have made a choice. I will go with the seperate 12V system and retain the stock 24 as well. I will have to make sure I plan out the project down to the last detail though. Once I biuld the wiring harness I do not want to go back into it and doing any hacking.