Charge 12v batt in 24v truck

[LiqTenEXp]

haha, I had 5 Ton on my brain. All my specifics are useless then. If you had a wiring diagram for its charging system I could come up with a similar concept, I think you get the idea...

Sorry

 

[mm58]

Oh no problem, I should have mentioned what truck I had in the beginning. Anyway, yes I get the basic idea and I will sketch out some ideas for how to hook everything up.

Basically, I'd like the batteries to charge from the alternator when the truck is running, and then switch to the solar panels when the engine is off. Might have to get a different charge controller for the solar

 

[Jeepsinker]

You can run two solar panels in series to output 24v. The charge controller may or may not accommodate that. I don't know which controller you have.

 

[mm58]

It's a HF solar system. Only 45 watts and designed for a 12v battery. It's three panels of 15w each

 

[Jeepsinker]

Ok, you should be able to daisy chain at least two of them to get 24v output but that will leave you with a third panel you can't do anything with because you don't want 36v. If they were higher quality panels you could run an infinite number of them at 24v.

 

[MarcusOReallyus]

Hmmm, that sounds like a possibility. Actually, the fridge will run on either 12 or 24. So maybe I should do this:
*Get a second battery and connect in series to the other one to have 24v.
*Run the fridge on 24v
*Charge the batteries from the 24v alternator just like the
trucks main batteries.

This is, by FAR, your simplest solution. Add a battery isolator to make sure you don't drain your starting batteries, and done.

If you want to buy a new solar charge controller to use your existing panels, that's good too.

Anything else is unnecessary complication and asking for trouble.

 

[swbradley1]

This is, by FAR, your simplest solution. Add a battery isolator to make sure you don't drain your starting batteries, and done.

If you want to buy a new solar charge controller to use your existing panels, that's good too.

Anything else is unnecessary complication and asking for trouble.

+1


I hate seeing complex when simple will do.

 

[glassk]

It's a HF solar system. Only 45 watts and designed for a 12v battery. It's three panels of 15w each

Add a relay in between the controller and let the input from one truck battery go to the Normally open terminal then the panels go to the Normally closed , when truck ignition is on the relay will energize and let power go to controller from truck battery, when turned off relay uses panels,

 

[mm58]

This is great! I appreciate all the input guys.

Can anyone suggest a place where I can get the above mentioned relay?


Mike

 

[MarcusOReallyus]

Amazon, eBay, any car parts store, Grainger, online or brick and mortar. Doesn't need to be anything fancy. All you need is a SPDT relay with a 24v coil that will handle the charging current.

Something like this would work.

http://www.amazon.com/Vehicle-Relay...d=1418671737&sr=1-5&keywords=SPDT+24VDC+relay


Here's a diagram to go with it:

http://www.the12volt.com/relays/relays.asp

 

[mm58]

I found a relay today at a local electronics parts place. It's an NTE R04-11D30-24. A lot heavier duty than I probably need, but that's okay with me.
Now I just need to find a 24v battery isolator...

 

[MtnSnow]

PowerStream makes great isolators (have one in our motor-home)

 

[mm58]

I will check out PowerStream. Thank you

 

[MarcusOReallyus]

I found a relay today at a local electronics parts place. It's an NTE R04-11D30-24. A lot heavier duty than I probably need, but that's okay with me.
Now I just need to find a 24v battery isolator...

Eh. Yes, that will work, but I'd be hesitant to use an open relay like that. Too easy for grime and gunk to get into the contacts. You could always put it in a small electronics kit box, I suppose.

 

[mm58]

Eh. Yes, that will work, but I'd be hesitant to use an open relay like that. Too easy for grime and gunk to get into the contacts. You could always put it in a small electronics kit box, I suppose.

True enough. I'm gonna have to make some kind of cover for it, or enclose the whole shebang in a box.

 

[MarcusOReallyus]

Something like this should work:

http://www.apogeekits.com/enclosure_project_box.htm

No endorsement - just found that link with a quick search.

 

[swbradley1]

You could also get a project box from MCM Electronics and the grommets for the holes and wire loom materials.

 

[mm58]

Thanks guys!

 

[MarcusOReallyus]

You could also get a project box from MCM Electronics and the grommets for the holes and wire loom materials.

Thanks for that tip! I'm not familiar with them. Have you done business with them?