Small Cooling Fan for Electrical Compartment

[wlooper89]

A little progress has been made. It is so easy to be sidetracked by other things. I completed most of the wiring changes for the cooling fan today. A wire to the meter pedestal routes DC positive to the fan and DC negative is available in the meter panel. One of the two relays and the black toggle switch on the same switchplate send 12V positive to the cooling fan. The other switch and relay control Battery Tender operation.



The other pic is of the back of the meter pedestal where the fan will be installed. The fan is to be placed on the round hole with a short hose to a similar opening in the back of the tongue box. A second vent in the back of the tongue box allows air to enter.



Bill

[wlooper89]

There is a little more progress on the cooling fan. Everything is back in the tongue box and wiring for the fan and associated switch and relay is completed. In the photo below the fan is churning away atop the converter struggling to lift off like a little moon lander but cannot quite do that. It will be mounted inside the back of the meter pedestal. A short hose with a clamp on each end will connect to one of the vents in the back of the tongue box. A larger opening in the back of the meter panel admits wires and warm air from inside the tongue box.

Just to the right of the relays, the black toggle switch turns the fan on or off. The upper relay disables the fan if AC is not available to the converter, so I can pretty much leave the switch on all the time unless the fan makes too much noise at night.

The other relay and switch are related to a utility light and the Battery Tender. One modification I made on power to a switched outlet for the Battery Tender had an unintended result. The Battery Tender is wired so it does not charge the battery if there is power to the converter that may also be charging the battery, but several months ago I routed AC power to the switched outlet for the Battery Tender through a circuit breaker inside the converter. Just yesterday I noticed the modification has caused the Battery Tender to be inoperative either with or without converter AC power. It should be easy to fix. In the meantime the WFCO converter or tow vehicle can charge the battery. With this converter I seldom use the Battery Tender anymore.

Bill

[Frog]

Bill:

I wish I had your knowledge and skill in wiring.

You mentioned you might get some gassing while hooked up to 110 power. I imagine you can regarge from your tow vehicle alternator. If so, after 3 or 4 days of dry camping with completed batteries, I would imagine you would have an even greater potential for gassing, especially as the battery ages.

Any way you could hook up a "snorkel" type PVC intake duct that would be in the airstream while towing. A small 1/4" hole in the bottom of the elbow would drain any potential water that might get caught in the airstream.

Just a non-electrical guys mechanical idea.

Joe

[wlooper89]

Joe,

Thank you for those kind words and great idea. Most of my electrical knowledge has come from staying at a Holiday Inn Express plus a little from a ham radio hobby many years ago.

I have not thought much about cooling the compartment while towing, but you have a good point. There will be a greater chance of battery gas if the battery is depleted. My thinking has been that nothing much electrical will be powered to create a spark. The fan, two little relays, converter and Battery Tender will be off. The only thing I can think of is the automatic charging relay (ACR) that connects the tow vehicle and trailer batteries. This link shows a photo of it mounted above the meter panel.
http://tnttt.com/album_ ... c_id=51581
The relay closes when battery voltage tells it there is a charger in the system. While towing the charging would be from tow vehicle. The ACR is designed for marine use, is supposed to be sealed and not give off sparks.

Hopefully the passive vents in the tongue box will be sufficient to disperse battery gas while towing.

Bill

[Frog]

Bill:

I'm sure you're right and even the fan is probably overkill with a sealed battery. Better safe than sorry.