Charging Cobra Battery while towing?
 

I just bought a new inclosed trailer and will be towing the cobra to Roebling Road soon and was wondering if you could charge the battery in th ecar while towing? There is a charging circuit on the 7 pin plug for charging a breakaway battery and a battery that is made into the trailer like in a travel trailer.

Has anyone done this?


I am also interested in putting a deep cycle battery in the trailer for runnig lights when the truck is not attached or to run a 110 volt converter for things like a small TV or radio.

Thanks Guys.

Can't help you with the car charging part probably could be done though at a sacrifice of one of the other batterys.
If I have this right you have 2 trailer batteries? I assume the "travel trailer" battery is the one that powers the interior lights/outlets? If so it could be changed out to a deep-cycle type, it would recieve it's charge when the trailer is plugged into the tow vechicle and the tow vechicle is running, otherwise it would stand alone and power the trailer not drawing off the vechicle battery bank.

Not sure what you mean by a "breakaway" battery? I'm very familiar with using battery power and setting them up on sailboats--in a boat you have a battery switch, simple setups uses a 1-both-2- off system rotary switch, 1 was used for the "start" battery in that position only the engine start battery was charged, 2 was for the "house bank" this position only charged the "house bank" and both charged both banks.

I for years used 6v batteries wired in series as a house bank up to about 2400 amp hours. And a heavy duty 12v start bettery. Then I switched out to 12v Rolls deep cycles for the house bank. Used these for almost 8 years until we sold the boat, 4-800 amp hour batteries. We often anchored for a week at a time, running refrigeration/freezer, lights, radios (vhf and ssb), and stereo, fans, inverter for small tv/vhs, before having to turn on the engine to recharge the "house bank".

If I were to go for a deep-cycle I'd seriously consider using the Rolls again. They'll absorb a super deep discharge and re-charge very fast--you do need a large amp alternator though.

Hope this helps

Ruble -
I put a 12v battery in a marine battery box inside my trailer and wired it to draw current from the truck's system through the trailer connection. As I recall, I ran a dedicated, heavy gage power wire from the truck battery to that pole on the trailer connection. I did that because I expected the battery to occasionally draw a high load during recharge and I didn't want to overload an ordinary circuit. ... As for charging the car while towing the trailer - If you have a battery in the trailer, all you'd need to charge the car would be a long set of jumper cables. The truck electrical system would be providing power to the trailer battery and the car.

If you have electric brakes, there is likely a small battery mounted on the tongue to provide emergency electrical power should the trailer come loose from the tow vehicle. On my trailer, that battery does not provide power to the interior lights or anything else but the brakes.

Ok so that is what a "breakaway battery" is--I was wondering.

GR yep that is a breakaway battery. It is about the size of a small motorcycle battery and it has a cable with a pin that pulls out if the trailer gets away. This sends power to the trailer brakes and in theory stops the trailer.

Be sure to use a device known as a battery isolator. This will allow the "towed" battery (Cobra, Boat, or RV) to be charged by the tow vehicle, but will not allow the tow vehicle to "use" that battery for its own needs. They allow the use of lighter gauge wire since there is no danger of the tow vehicle trying to use the "towed" battery for cranking power. They are available from marine or RV dealers.

Forgot to mention the "isolator" yeah definitely need one of those. RV places are less expensive than using marine type switches and isolators--marine type are more corrosion proof and more expensive

Thanks guys that is what I needed

A great source for any of this battery charging/RV/ serious electrical stuff as well as advice is Wrangler Power Products (or maybe Wrangler NW Power Products). Try a google search.

These guys have everything you need and their catalog has some cartoons showing how it works. You can also call them for advice. Their stuff is good quality.