Derale Trans Cooler

[gr8scott]

So I installed a trans cooler the other day and it works great. It came with a inline t-stat that turns the fan on/off. I noticed that when the fan turns on, my voltmeter goes from 14v to 13v, and when it turns off it goes back to 14v. I do run a 130 amp 3G alt so I figured I'd have more than enough juice to run a simple trans cooler w/o it affecting my voltage so much. Is my voltage drop when the fan turns on to be expected, or am I missing something?

I tried 3 different switched wires off my Centech harness with the same result. I also temporarily jumped it straight to the battery and that did not affect my voltage, it stayed at 14v, but then I figured it was pulling power from the baterry as opposed to the alternator. What am I missing? TIA,

Scott

http://www.summitracing.com/parts/DER-13900/?rtype=10

 

[broncnaz]

fan probably takes at least 10 amps to run I would expect a voltage drop nothing to really worry about unless it was sucking it down to like 11 volts. Turn on your head lights the voltage guage probably does the same thing. hooking directly to the battery basically bypasses the voltage guage and alternator thats why you dont see a change that way

 

[73azbronco]

as long as you exceed the 12.6ish volts, your not running down the battery..

 

[gr8scott]

Cool, thanks for the replies!

 

[strokers]

It sounds like you are taxing your harness by running the fan off switched power. The fan that probally pulls 10 amps should be ran off its own relay.

 

[Viperwolf1]

It sounds like you are taxing your harness by running the fan off switched power. The fan that probally pulls 10 amps should be ran off its own relay.

Exactly. Harness doesn't have enough current capacity.

 

[66fora69er]

Is there a problem running it off the battery to a switch?

 

[Viperwolf1]

Is there a problem running it off the battery to a switch?

All the wiring and switch will need to be large enough to handle the current draw. If you use a relay only some of the wiring needs to carry the large current. The switch and switch wiring can be smaller. Don't forget you'll need to fuse it as well.

 

[66fora69er]

Thanks Viper. I did run a fusible link (20 amp) but no relay. from the battery, fuse, switch to cooler. Just wire a relay in between the fuse and the switch? Thanks

 

[Viperwolf1]

Thanks Viper. I did run a fusible link (20 amp) but no relay. from the battery, fuse, switch to cooler. Just wire a relay in between the fuse and the switch? Thanks

If you've already wired it and used a good switch and heavy wire I wouldn't change it.

Do some searches on relay wiring and you should find some good diagrams.

 

[strokers]

Do a google search on a power distribution block there are a few styles that you can run off the pos. Side of start solenoid. Installing one of these with a simple relay circut will keep large hi amp wires out of dash and keep the wires shorter. It will also allow you to use switched power to activate the relays

 

[66fora69er]

Thanks. didnt mean to hijack the thread but I just installed the same trans cooler

 

[gr8scott]

Thanks. didnt mean to hijack the thread but I just installed the same trans cooler

Not a problem, 66.

Okay, so a relay would help my situation. And I could still use the in-line t-stat to control the switched power, it would turn on the relay, relay would power the fan. So something like this would work:
http://www.summitracing.com/parts/PRF-30101/?rtype=10
Thanks all,
Scott

 

[Viperwolf1]

That would work.

 

[gr8scott]

Thanks Viperwolf1 and everyone else who helped! You guys ROCK!

 

[gr8scott]

Success! No more voltage drop w/ fan relay installed

 

[kc15842]

Where did you mount the cooler? I'm using the radiator cooler and a B & M installed in the front left corner (passenger side) of the radiator. It still gets up to 210 while crawling. I would feel much more confident if I could keep it no more than 200. Thanks