Charging The Batteries From The TV While Running The Refrigerator On Battery - Page 5

scrubjaysnest · 01-12-2011, 10:18 AM

Quote:

Originally Posted by ShrimpBurrito

scrubjay - You need something like Phil bought, and you'll find them within the trucking industry, and these larger connectors are what connects the pigtail on 53-foot trailers to the tractor.

Here's a 2-wire connector (that's all you need) that accepts 4 and 6 gauge -- I actually was in contact with Pollak about it taking 8 gauge, and he said you might be able to get it to work, but it wouldn't be pretty. He advised against it. But you might consider using 6 gauge instead.

http://www.etrailer.com/Wiring/Pollak/PK12800.html

You won't find any 7-pin Pollak connector that takes 8 gauge wire -- I looked hard last year.

Dave

Dave

6 gauge is out...already have the 8 gauge...... I wasn't planing on a second 7 pin anyway as I knew they were to small for the 8.

The problem with trying to make the 8 gauge work with a 6 gauge plug is the potential heat build up from excessive volt drop. Now you have a potential fire hazard. Just need to get into Ocala to a trailer dealer there. They have a bunch of different style pollak's since they build horse trailers.

scrubjaysnest · 01-12-2011, 10:23 AM

That looks like an option for sure.

**ShrimpBurrito** · 01-12-2011, 10:49 AM

Quote:

Originally Posted by scrubjaysnest

The problem with trying to make the 8 gauge work with a 6 gauge plug is the potential heat build up from excessive volt drop. Now you have a potential fire hazard.

Excessive voltage drop going from a smaller wire to a larger connector? How?

Another option is to simply split up your 8 gauge wire among a few different terminals. I would avoid using a 7-pin connector, however, as that is a recipe for getting it mixed up with your existing 7-pin connector.

Dave

scrubjaysnest · 01-12-2011, 02:30 PM

Quote:

Originally Posted by ShrimpBurrito

Excessive voltage drop going from a smaller wire to a larger connector? How?

...................snip.........................
Dave

Surface contact between the wire and screw but then style will be a player here also. If the screw is concave you should get more surface contact; were as if it is convex stranded wire has a better chance to be pushed to one side increasing the chances of poorer contact. Its just something one has to be careful of. Now watch I'll have gotten my concave and convex mixed up.

Philip · 01-17-2011, 10:24 AM

Hello Ken,

I am not sure I understand what you are trying to do but in my opinion you are making it all too complicated.

Here is what I would do in your situation, if I understand it correctly. If you have a spare battery in the TV, I would get some heavy duty welding cable(2ga is $1.50/ft - smaller is cheaper. Welding cable is so flexable it is like a wet noodle and easy to work with. Connect this cable(+ $ -) from your TV starter battery to your spare battery then on to a new two pole male plug (pollak from etrailer.com) on the back of your TV. Connect new welding cable directly to your TM batteries from the female end of the new polack plug placed on the TM. Leave the existing TM plug as is!

That's it as far as I can see. Your TV will charge your spare battery and your TM batteries while towing - or when you are at a site. Just make the wire size as large as you can afford.

I hope it helps you on your project. Just let me know if there is something I don't understand about your setup.

Take care,

Phil

**Bill** · 01-17-2011, 11:08 AM

Philip -

I tend to agree. Ken and I have talked about this off-line, so this is really a question for you.

Why such huge wire?

I made this exact change (though I don't have a "side battery"), using #10 wire, and it worked perfectly. I would think that #8 would be overkill. Why go all the way to #2?

I think we're all agreed that the new wiring must include two wires - power and ground. And an additional connector pair will be needed, no matter what size wire is used - some folks have tried splicing into the existing 7-pin Bargman, but not with good results. The 2-pole Pollack connector discussed should be a good choice, though there are others.

One further thing. It could be better to attach the front end of the new pair of wires directly to the alternator output and ground terminals, rather than to the tow vehicle battery. In theory it should make very little difference, but some cars, especially older ones, tend to develop a bit of corrosion in the connections between alternator and battery (ask me how I know this!) Might as well go as close to the source as possible.

Just my thoughts. The need for overly big wire confuses me.

Bill

TexasCamper · 01-17-2011, 08:12 PM

OK, I've been reading this thread with interest, and understand that I can't quickly charge my trailer battery from my TV using the standard "thin" TV wiring supplied by the mfr to the 7-pin connector....

....but if I'm at a campground and leave my TV running, and connect a spare 12V trailer battery to my TV battery using fairly thick jumper cables, how long would it take to charge from a drained state (say ~50% capacity), assuming I could safely barricade off the area so no one gets injured during the process.

Are we in the 10-15 min range, 20-30 min range, or above?

**ShrimpBurrito** · 01-17-2011, 08:44 PM

Quote:

Originally Posted by TexasCamper

Are we in the 10-15 min range, 20-30 min range, or above?

Above. You're probably talking a couple of hours. May be ok in a pinch, but definitely not a good idea to plan on doing that.

Dave

scrubjaysnest · 01-18-2011, 06:08 AM

Quote:

Originally Posted by TexasCamper

OK, I've been reading this thread with interest, and understand that I can't quickly charge my trailer battery from my TV using the standard "thin" TV wiring supplied by the mfr to the 7-pin connector....

....but if I'm at a campground and leave my TV running, and connect a spare 12V trailer battery to my TV battery using fairly thick jumper cables, how long would it take to charge from a drained state (say ~50% capacity), assuming I could safely barricade off the area so no one gets injured during the process.

Are we in the 10-15 min range, 20-30 min range, or above?

^^^^what Dave said^^^^^ Our experience from 6 months on the road was about 3 hours for a 95AH marine(hybrid) deep cycle. I feed the battery from an isolator, about 0.5V drop through a pair of #12 wires, equivalent to #6 gauge wire. The battery was grounded through the frame. We charged our battery while exploring back roads, that way the TV wasn't just idling at the campsite. Just a quick note on this. With the TM hooked up to the TV through the bargman only volt drop from the TV to the TM battery was about 1. Without pre cooling the refrig and turning it on the volt drop went to over 2 volts which means the battery in the TM would never charge. That is why I am doing a variation of Philip's and Bill's mod.

Barb&Tim · 01-18-2011, 08:36 AM

Quote:

Originally Posted by scrubjaysnest

I feed the battery from an isolator, about 0.5V drop through a pair of #12 wires, equivalent to #6 gauge wire.

Actually, although running 2 wires of the same gauge size in parallel does cut the resistance in half, it only drops the equivalent gauge size by ~3 -- or in this case 9AWG.

Tim