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Any advice on a preferred 24V to 12V stepdown? I need to run the trucks' heater fan, and a cig. lighter socket (suitably hidden) for cel charger, gps, etc.
I'd prefer not to split a tap off one battery - on the other hand, I'd also prefer not spending 300+ on it...

Mark@Sea wrote:Any advice on a preferred 24V to 12V stepdown? I need to run the trucks' heater fan, and a cig. lighter socket (suitably hidden) for cel charger, gps, etc.
I'd prefer not to split a tap off one battery - on the other hand, I'd also prefer not spending 300+ on it...

I don't know of a good, cheap way to do this. Pulling it off 1 battery is certainly not a good option.

The absolute best way is to go all 12 or stay all 24, there are some other options if your 12 volt demand won't be too great, my own opinion is this, I'd rather spend money on a complete conversion to a 12 volt system than spend it on inverters and such. I've undone many such systems on trucks, especially fire service trucks as they generally demand many 12 volt accessories. I've never seen it done in a way I was impressed with other than a complete conversion.

I hear that these work very well,but have not used one myself ...yet. I won't be changing my 24 volt system any time soon,because it works great. However,I'd like a radio,or perhaps a spot light.

http://www.opektech.com/Voltage_reducers.html

http://cgi.ebay.com/DC-VOLTAGE-REDUCER- ... 563bc747f7

Here's another... http://cgi.ebay.com/DC-REDUCER-24-12-VO ... 335ba83fd4

Hello Mark,

I would look hard at the dollar signs and do the math. If you have a perfectly good 24 volt system and have a need for a 12 volt appliance then I think you'll find the cost of a converter will be about 1/50th of the cost of dumping your 24 volt and converting to a full 12 volt system.

If you take the pains to install a quality converter properly using the correct circuit protection devices, the correct gage wiring and positively ID the 12 volt wiring as 12 volt the installation would function quite well and be absolutely safe to run with.

I would try to keep the 12 volt loads under 10 amp. If your heater fan wants more than that I think you would do better and realize more longevity by converting the heater fan motor to a 24 volt unit.

I just finished installing a brand new harness, so I believe I will stay with the 24 volt system. Opened up my ancient aftermarket heater today to see how hard a motor swap would be... that heater was not built to come apart. Might start looking for a new heater...

You have several options on heaters. There are the stock left fender mount hot water and gas fired types. The late WWII heaters fit under the passenger side of the dash OK. The M151 hot water heater is fairly simple to adapt if you don't want to mount a heater on the top of the left fender.

Cabell has a nice writeup on them here:
http://www.garbee.net/~cabell/heater.htm

Mark,this is the heater that I have under the glove box in my M. Paint it OD,and it looks great.

http://www.summitracing.com/parts/SUM-991105/?rtype=10

Another option is to look at 24V electric heaters. You can find some in marine (boat - lower case m) suppliers. Of course, anything nautical = $$$, but it may be worth a look. I put in a great 24V wiper system built for boats. You never know what you'll find.

On that note, I've been tinkering with filtered 24 - 12 VDC converter design (LM325s). I'll post if I find something useful.

I've found a 24v version of the heater I currently have... still need 12v for cel/ gps, but those are very low current draw, so I will probably run a tap...

Mark@Sea wrote:I've found a 24v version of the heater I currently have... still need 12v for cel/ gps, but those are very low current draw, so I will probably run a tap...

A cell phone and gps doesn't use 15 amps. You'll be fine.

I started with 12V and have stayed with it, as I never know if I'm going to need a jump start from a "civilian" sometime....
Gary

24 / 48 V @ 10 Amps Battery Equalizer and DC Autotransformer
Application

This rugged and versatile unit is used to power a small load at 24 V from a 48 V battery, or to power a small 48 V load from a 24 V battery.
It functions both ways, producing 24 V @ 10 Amps from a 48 V input or can be connected backwards to produce 48 V @ 5 Amps from a 24 V input.

When connected as a battery equalizer, it allows large transient 24 V loads to be taken off the centre tap of a 48 V battery (made of 2 X 24 V batteries) without fear of upsetting the voltage balance of the battery and destroying the 48 V battery system that would otherwise occur.
Model: EQ 24/48-10

whoops, i posted the wrong one but there is a converter for 12/24 volt.

they are very nice. solarconverter.com