24v to 12v Without Converter or Transformer

[rtbcoop]

A quick question for the EE's out here, would a setup like this work for equally tapping 12v off the two batteries? The diodes would keep the betteries from shorting out but I am not sure if the ground on the second batteries would screw things up. Just a thought and wanted some input.

Thanks

 

[steelandcanvas]

Use a 24 volt to 12 volt converter, or install a 12 volt alternator (in addition to the 24 volt unit) and a battery. One push of the starter button and you'll let all the smoke out of those diodes.

 

[swbradley1]

http://www.amazon.com/Pyle-PSWNV720-Power-Converter-Technology/dp/B003P17X8I

 

[FireFighterHill]

He could also use a battery equalizer, though they tend be alot more expensive.

 

[rtbcoop]

Yeah, I know all the other options, was more curious why this WOULDN'T work. Frying the diodes is a good point; not sure if they make high-load diodes...

 

[212sparky]

the cost of the diodes would far excede the cost of a 12 volt alternator setup.

 

[swbradley1]

They do make diodes...

http://www.vishay.com/diodes/med-high-diodes/on-state-current-gteq-800-a-lteq-1200-a/

 

[FireFighterHill]

What you are doing is running the same two batteries in both a series and parallel setup at the same time. From what I have read that is not possible. http://www.batterystuff.com/kb/articles/battery-articles/battery-bank-tutorial.html

 

[swbradley1]

You can always build it using two D-cell batteries and low power diodes.

Reduces the risk of arc welding or explosions rather than using two 1150CA automotive batteries.

 

[zebedee]

http://www.amazon.com/Pyle-PSWNV720-Power-Converter-Technology/dp/B003P17X8I

Thanks for the heads up on the inverter, however the revues of this product are not 100% +ve....... 5:2 fore/against.
Just thought I'd add this incase people jumped without reading the revues.

I'm going with a small car alternator...

 

[swbradley1]

Correct, they are not 100%.

Get 10 people in a room and have them agree on what to have for lunch. I read the reviews and still bought it.

 

[FormerNewMVGuy]

I also bought the inverter, I have two spring seats in myM813A1 with two ammo cans mounted between the seats, I mounted the inverter in one of the ammo cans , and installed a 12 volt marine plug through the side of the can, now i can charge my phone , plug in my GPS , My 12 volt spotlight, CB , ETC.....
It works great so far!

 

[steelandcanvas]

I also bought the inverter, I have two spring seats in myM813A1 with two ammo cans mounted between the seats, I mounted the inverter in one of the ammo cans , and installed a 12 volt marine plug through the side of the can, now i can charge my phone , plug in my GPS , My 12 volt spotlight, CB , ETC.....
It works great so far!

Any concern about heat build-up inside the can? Did you have to vent the can or use a fan to keep the converter cool?

 

[swbradley1]

You could always use a small 12v muffin fan on the side of an ammo can. Using a can is what I was thinking of doing as well with mine.

 

[mikew]

Your circuit won't work.

Go to radio shack and buy 4 cheap diodes (1 amp ones, etc.) and hook up as per your schematic. Nothing will smoke.

Measure the output voltage from the diodes that you label 12v, you'll find that you have 24 volts instead.

The only diode that will flow electricity in that diagram is the one connected to the +24v post of the battery, the other ones are doing nothing.

As stated, you can't do both series and parallel at the same time.

Converter, battery balancer or dual alternators are your best bet.

How many amps at 12v do you need? what are you trying to operate?

 

[steelandcanvas]

You could always use a small 12v muffin fan on the side of an ammo can. Using a can is what I was thinking of doing as well with mine.

Seems to me you'd want to have some cross ventilation in that can to keep the heat from building up, and shortening the life of the converter. A 12 or 24 VDC Muffin Fan would work well.

 

[FireFighterHill]

To clarify you CAN do Parallel and Series at the same time but you need at least 4 batteries. This is how a 4 battery setup works in our trucks (correct me if im wrong please), 2 of each in parallel to make 12volts at double the capacity then you connect those two pairs in series to get 24 volts.

 

[moving chicane]

To clarify you CAN do Parallel and Series at the same time but you need at least 4 batteries. This is how a 4 battery setup works in our trucks (correct me if im wrong please), 2 of each in parallel to make 12volts at double the capacity then you connect those two pairs in series to get 24 volts.

Yes but the output is still 24V only

 

[FireFighterHill]

According to everything ive read you can get 12 volt from the batteries on a 5ton and the truck comes from the factory wired to utilize it for the low speed heater fan. I know the 12volts dont come from the alternator and there is no 24 to 12 volt convertor that leaves pulling 12 volts from the batteries. In my mind the only way this is possible is to pull that 12volts from the parallel batteries or a single battery before the series connection.

http://www.steelsoldiers.com/showth...ck-with-M931&p=1168086&viewfull=1#post1168086

 

[dependable]

I may be missing the point of original post, but if you just want a moderate amount of 12 volt off 24 volt series system, can't you tap off the back of the first battery, as is done in CUCVs for the 12v part of the system? (except 1010)