Custom Ramcharger fan harness questions...

I just picked up a RC fan for an upcoming cooling system overhaul/upgrade. It's going to be used on a Griffin 31" x 19", and I've decided I want to use a switch setup for my application. I'm aware of the excellent DCC controller, but right now I prefer to use a switch setup.

I couldn't see spending the $60 extra for that wiring harness that Ramcharger offers, and I have plenty of wiring supplies here from stereo installs and such. I've decided to make my own, but I could still use some suggestions on part selection. My goal is to keep this as cheap as possible, but using high quality stereo grade stuff.

Now, from this picture of the Ramcharger harness, I'm assuming I'll need two relays, some decent wire, two-position switch, fuse holder for power lead, and fuse holder for switch.



Now, I've decided on using the 8ga power wire I have left over from a recent wiring project. I also have some 8ga that I'll use for the ground. The rest of the wire, heat shrink, terminals, etc I already have here as well. These are the parts list I've gathered so far.

(2) Bosch 30A Relays - $2.19ea

I'm getting two types of relay sockets and I’ll figure on which one to use depending on how I mount everything...

(2) 5-Pin Relay Socket (single) - $1.50ea

(1) 5-pin Relay Socket (dual) - $1.90ea

I also saw this one, but I'm not sure if I need the diode...

5-Pin Relay Socket w/Diode - $1.50ea

This is the fuse holder I've decided on for the relay to battery power lead...

8ga Inline AGU Fuse Holder - $2.25ea

Those are parts I've decided on so far, but I haven't ordered any thing yet. So, I have a couple of questions still..

1. What fuse rating should I go with on the power lead? From my research, it seems the RC fan pulls a max spike of about 35A from off to high...so a 40A? 30A?

2. What is the difference in the relay socket with a diode, and is it something I should get for this application?

3. I'm having a bit of trouble finding two position switches for both low and high operation. What are some of my options here? Could I run two separate switches? One for low, and one for high?

4. What size fuse should I use on the relay to switch leads?

Once I get the project all done, I'll try to do a mini write-up for anyone else that might want to make a custom harness. Anyone with the RC fan now could help greatly by taking some pics or describing the wires coming off the fan as well. From what I've seen so far the RC fan draws the max spike of about 35A, then a constant ~24A on high. I'll probably never use high, but I would like to have the option.

Any input would be greatly appreciated...

Bump...

Thanks for the info. I'll see which works better on the sockets, but I was figuring on the singles might be easier.

It looks like there are two power wires that come off the RC fan, and to get high, both need to be activated. From the pic of the RC harness I'm guessing they use the two relays to control each speed.

I assume that when the switch is on "low", only one relay is activated, and when it's on "high", the second one comes on. If this is the case, two single switches should work fine. You could turn on or the other on for low, or both switches for high.

Anyone else have any ideas?

No one has ever done something like this?

I know this fan is popular. Does anyone have the RC harness that could answer a few questions?

Anyone??

Thanks man, you are like the only one to reply.

I went ahead and ordered most of the stuff, I'm just trying to figure what those two black cylinders are on the RC harness.

I've found out some more info on the power draw. Apparently, the RC fan has a spike of about 30A from off to high, and then a constant ~23-24A on high. I'm primarily only going to have it on low, so the draw should be even lower.

As it stands now, the price of the fan and the components will come in under $100...that's a hell of a deal IMO.

It seems like that everyone just uses the DCC or some other sort of temperature control, but I prefer to use a switch for my application. I guess no one uses a switch type setup....

Thanks anyway...