Electrical Ideas

[cliffyp]

So I'm currently having alternator troubles and it got me thinking. I live in South Texas where it's hot and sunny all year long, so I would love to have A/C. One option is to convert to 12v system, freeing up an alternator bracket for A/C stuff.

I've seen people on threads here talking about Solargizer, so I looked it up. Turns out it isn't supposed to be a charger.

What if a different solar panel was put on roof or hood that was intended to be a charger connected to one battery and one alternator connected to the other. This would free up a bracket for A/C while still maintaining 24v system.

The only electrical draw on the system would be the starter when cranked and the blower for A/C. Even if the solar panel wasn't as efficient as an alternator it has more time to charge since it will still charge while the engine is not running.

So, is this a plausible idea?

 

[Skinny]

Interesting...

How about some type of isolation system to wire the batteries in parallel when the engine is running, then in series for starting. Wouldn't need a panel then.

 

[Barrman]

I am trying to write this sound it doesn't sound like a threat or mean. Please read it that way.

The people on this site for the most part learn to use the stock system, the military manuals were made a huge expense to help you fix the stock system and most of the comments on this site will be in relation to a stock system. There is a popular 12 volt conversion done called the Roscommon. They even have instructions on line. Once you stray from either stock or the accepted 12 volt conversion. Most of your online help will go away. You will become your own system engineer, designer and the only qualified mechanic to work on it.

Why not just add on one of the available air conditioning kits and fix your alternators so everything works like it is supposed to?

Here is the 12 volt conversion site:

http://www.roscommonequipmentcenter.com/news_notes/nn10.pdf

 

[wayne pick]

Good advice.

 

[MarcusOReallyus]

Cliffy, electricity is my thing, but I'm a newbie to CUCVs, so take this for what it's worth, whatever that is:

What you are suggesting is theoretically possible.

I wouldn't touch it with a 10 foot pole.

 

[cliffyp]

I get what y'all are saying. I've picked up on the fact that converting to 12v is somewhat poo-pooed on, if for no other reason than it deviates from what is collectively known about. I've steered clear for that reason.

This is mostly just musing. It seems like less of a modification if you are just swapping an alternator for a solar panel. Single devices doing identical jobs. Seems like you could test it for a while and just put the alternator right back in if the electrical system wasn't behaving.

No offense taken from your comment Barrman. I totally get what you're saying. I just rebuilt one of my alternators but it still isn't charging, so I'm hunting down the problem. An idea pooped into my head so I figured I'd bounce it off the guys that may not know me, but I've been reading from everyday for almost a year. As to the air condition kits, I haven't read a thread yet that seemed like a great solution. Perhaps I just haven't searched well enough though. It seems as though everyone is searching for a place for a bracket for A/C.

Some people seem to discourage alterations for the purist aspect. I'm not into that. I'm also not into making changes just for the sake of change. I didn't by my CUCV to try and have it look the way it did when it left the factory floor, nor to mod the heck out of it with every after market doo-dad in existence. I bought it to have a sturdy truck that I could learn about, and the existence of the TM's is what gave me the confidence to purchase.

Curiosity and learning about the things that improve my life is what motivates me. I'm rebuilding a 700r4 for this truck because it will make it much more enjoyable to drive. I bought the ATSG service manual and I'm doing to the work myself so I can learn about it.
Is it an alteration: Yes
Will it work when I'm done: Who knows?
Will my wife and kids ever let me have the time to finish: God only knows!

Back to theoretical musing: Skinny, is this isolator you speak of something that exists? I can't mentally work out how something would switch between parallel and series.

 

[wayne pick]

No one here will ever deny you advice, or shun you for modifying your truck. It's your truck, make it as comfortable and reliable as you see fit. There are many well thought out and trick mods under the OD sheet metal made by some really sharp guys here. If we didn't modify these trucks for the better, there wouldn't be too much to talk about.

 

[Skinny]

I agree that keeping the twin alternators and adding a standard AC compressor would be easiest. Having said that, I am one to modify things.

I would measure the wattage used to crank the engine over times the number of cranking sessions per day times 50% just for the heck of it. After calculating, size the panel for a three day stretch of no sun just for redundancy.

I have the stock 24v system but will be adding a Schumacher ship n shore battery bank charger so when my rig is unused for long times in winter, I can plug it in and have hot oil, coolant, and batteries...just for insurance.

 

[BIG_RED]

When my ALT2 was disconnected (blown 24 volt exciter fuse.. I noticed the dash light wasn't coming on at start but didn't have time to deal with it till the weekend), I was able to cold start my truck probably 15 times without it before I notice that it was starting to get slow to crank and fixed it. I have 1100 CCA Batteries. So 3 days without sun (or whatever second battery charging system you rig up) would probably be fine (unless it was very cold outside).

That said (please don't take offence to this), IMHO solar panels are more or less useless for charging anything in a reasonable amount of time.. unless you use HUGE ones, which then present a "breakage hazard" mounted on a CUCV bumping around on the road.

If you're an electrical guy - I'm sure you could figure out how to run the batteries in series for starting and parallel at all other times.. You only really need 3 high amperage contactors. One spliced into the wire that connects the batteries in series (which would be "on" for starting, and off the rest of the time), and two more connecting (1)the negative terminal of BAT2 to ground and (2) the positive to the positive terminal of BAT1 (which would both be "on" while driving and "off" while starting). The control circuitry would be a little more complicated, making sure that there is no failure that can cause all of the contactors to be "on" at the same time, because that would blow up BAT2 in seconds.. but I'm sure you could figure it out. 3 contactors and some small switches/relays would cost you less than a large enough panel to keep BAT2 topped up. And there's no panel to break.

BUT: As said before, you're up a creek without a paddle if you run into trouble.. nobody here can help you with a custom wiring job. I'd just fix your alternators and hang a compressor under the pass side alternator. But, it's your truck. Best of luck to you.

 

[cliffyp]

Well I haven't done any calculating but, since my Gen 1 light came on 2 weeks ago or so, the truck has been started 6 times. When its off the front battery is still reading 12.5, so 6 starts plus 2 weeks of sitting hasn't put a dent in the battery's charge. I'm thinking that one of the little battery maintainers will just keep it topped off. I just ordered a 1.8 watt inside windshield unit from northern tool.

NPower Solar Battery Maintainer — 1.8 Watt | Amorphous Solar Panels| Northern Tool + Equipment

I have a Gen 1 problem, so I might as well hook this up while I sort out the problem. I can always upgrade to a better system if it works but seems to need more power.
I do want to fix Gen 1, it was just rebuilt but still not working correctly.

 

[cliffyp]

making sure that there is no failure that can cause all of the contactors to be "on" at the same time, because that would blow up BAT2 in seconds.. but I'm sure you could figure it out.

This is what I was thinking and it makes the idea a little scary!

 

[Skinny]

I was doing a little light reading in a boat book the other night. You could keep the 24c system and just use a single 24v alternator, this way you have room for the compressor. The only problem with this is you cannot draw 12v off the first battery. It makes the system out of balance during the charging process. You would have to run a converter for the cab circuits. I think this would be the best and most proven setup as it already is common practice in the marine industry.

I would stay away from a HMMWV alternator as it's gigantic and has a serpentine drive. Not to mention the cost.

 

[mistaken1]

Look online at a 280 watt solar panel. Roughly 3.5' x 5.5'. 280W/14V=20A compare that to a 100A alternator (assuming you can find a 280W 12V nominal panel).

You will need a charge controller. There are charts for solar Insolation, I am guessing you would get 6 to 7 hours on average. The voltage and current on the solar panel will ramp up until the sun is overhead and then ramp down again. As others have stated you can do it, the question is, is it practical.

 

[Keith_J]

Alternator rebuilding kits are inexpensive. Having 100 amperes of 28 volts IS useful. For instance, you can run a 2.3 kW inverter off 24 volt using 4 AWG wire and still have power left over to run the truck.

I understand the need for air conditioning yet I didn't want to fool with the under-hood nightmare of non-standard belts etc. So I designed a 28 volt powered air conditioning unit which I am assembling currently. Aside from the bracket to join the motor and compressor, all are off the shelf components. The compressor is a Sanden SD7B10 with the clutch hub modified to join to a Lovejoy L095 flex coupling.

I've even looked into driving the evaporator blower off the rear battery, using a lead off the 12 volt switched as the NEGATIVE for the blower. The blower has isolated negative/ground, all I will need is a 15 amp circuit breaker off the 24 volt side to protect the wiring.