My new 20 amp 24/12 volt converter arrived. I already have a 15A unit in place, and it was cheaper to buy another small one then one 40A. I'm going to split my 12 v loads between the two...should I wire them from separate pickups on the switched 24v side of my fuse box? or is just adding a jumper wire to the existing unit ok?
24/12 volt converter wiring
- Thread starter Zekester
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I would think that would depend on how big the fuse is that you're drawing from on the 24V side. 
If it's 40A or above, I guess you'd be fine. Otherwise, draw from another circuit.
Or did I misunderstand your question?
If it's 40A or above, I guess you'd be fine. Otherwise, draw from another circuit.
Or did I misunderstand your question?
Check wire gauges used (AWG)
Depends on how you have wired the truck and the converters. Why?...
I assume that the amp rating for the converters is the output rating, i.e. a 24V to 12V 20A converter is 20A @ 12V nominal. For arguments sake assuming no conversion losses (in reality anywhere from 80 to 95% efficient) then the converter will draw 12V/24V x 20A = 10A from the 24V side.
Again for arguments sake, assume you have 2 similar converters attached to the same wiring, you'll be drawing twice the current, i.e. 20A, on the 24V side.
So, the wiring, switches and relays will need to be rated for the current. 20A isn't much but if you don't use the right gauge wire you could overheat it (it'd have to be really small diameter wire though). Wire gauge and current carrying info can be found on the web, e.g.
http://www.powerstream.com/Wire_Size.htm
The current carrying capability is influenced by many factors, mostly if you use it in a bundle with other wires. You could take a value between the Maximum amps for chassis wiring & Power transmission. I always take a conservative approach and have been known to use AWG 10 on the 12V side of my converter to go to a big 12V heater motor. Overkill, I admit but I had the wire and it fitted in the connections to be used.
Without knowing anything about your truck set-up, I'd advise running a separate 24V feed to the new converter. Another idea you may wish to consider is connecting the converters directly to the batteries via an accessory-switched relay. This avoids using the vehicle harness in any way and you know where and through which conductors and connectors the current is flowing. The converter has its own removable fuse built in. On the 12V side, I installed a separate fuse block for the 12V loads. This is how the converter is set up in my truck.
P.S. Did you fix your pyrometer issue yet? Take a look at eleblanc's thread for more ideas...
Depends on how you have wired the truck and the converters. Why?...
I assume that the amp rating for the converters is the output rating, i.e. a 24V to 12V 20A converter is 20A @ 12V nominal. For arguments sake assuming no conversion losses (in reality anywhere from 80 to 95% efficient) then the converter will draw 12V/24V x 20A = 10A from the 24V side.
Again for arguments sake, assume you have 2 similar converters attached to the same wiring, you'll be drawing twice the current, i.e. 20A, on the 24V side.
So, the wiring, switches and relays will need to be rated for the current. 20A isn't much but if you don't use the right gauge wire you could overheat it (it'd have to be really small diameter wire though). Wire gauge and current carrying info can be found on the web, e.g.
http://www.powerstream.com/Wire_Size.htm
The current carrying capability is influenced by many factors, mostly if you use it in a bundle with other wires. You could take a value between the Maximum amps for chassis wiring & Power transmission. I always take a conservative approach and have been known to use AWG 10 on the 12V side of my converter to go to a big 12V heater motor. Overkill, I admit but I had the wire and it fitted in the connections to be used.
Without knowing anything about your truck set-up, I'd advise running a separate 24V feed to the new converter. Another idea you may wish to consider is connecting the converters directly to the batteries via an accessory-switched relay. This avoids using the vehicle harness in any way and you know where and through which conductors and connectors the current is flowing. The converter has its own removable fuse built in. On the 12V side, I installed a separate fuse block for the 12V loads. This is how the converter is set up in my truck.
P.S. Did you fix your pyrometer issue yet? Take a look at eleblanc's thread for more ideas...
- Thread starter
- #4
I'm going to go with the relays and the 10 ga direct off the batteries...
Once I get this straightened out, then I will tackle the pyro...right now due to the what I think is an underpowered converter, it's causing some of the problems, if not it's at least affecting my gauge....
Once I get this straightened out, then I will tackle the pyro...right now due to the what I think is an underpowered converter, it's causing some of the problems, if not it's at least affecting my gauge....