Charging Battery From Tow Vehicle

[HiHoAgRV]

Originally Posted by ostream

... The OEM converter-charger in new Airstreams is adequate at best.

We agree on this point. It'll boil a battery quicker than a Southern'er will a crawfish...

Originally Posted by ostream

The cost (parts+labor) to upgrade to an onboard 3-stage converter-charger is much higher than a BatteryMinder....

I guess I miss the point here...a battery minder is a long term float charger, right?
I was sayin'...even the crappy onboard charger (see above) will top off the batteries quicker than a Walmart clip on unit...BUT a good 3 stage will do it faster and without fryin the lead cells...
http://www.airforums.com/forums/f42/...tml#post568527

[KirkBoy]

Hello!
I don't know about all the others that have posted here, but my current Dometic and my past Norcold refrigerators all required 12 VDC even when switched to run on LP. My current fridge has an LED control panel and it's always on when the fridge is running. I've tried to find out how many amps the fridge uses while on LP, but the owner's manual doesn't say; it only lists amps when using 12 VDC to actually cool the unit. I'll bet it's pulling at least 1 amp. Does anybody know?
Kirk

[bovk]

I stay on one battery for 10 days and could probably longer.
The trailer consumes amps even when everything is OFF. So battery has to be disconnected when not needed. In my case it consumes about 0.4 amps so in 2 days half of my battery would be gone.
I assume you will take the tow vehicle for a ride at least every other day. When I get back I equalize the batteries between camper and vehicle. Take measurements - >12.7 Volts OK, <12.25 no good.

[HiHoAgRV]

Originally Posted by KirkBoy

Hello!
I don't know about all the others that have posted here, but my current Dometic and my past Norcold refrigerators all required 12 VDC even when switched to run on LP. My current fridge has an LED control panel and it's always on when the fridge is running. I've tried to find out how many amps the fridge uses while on LP, but the owner's manual doesn't say; it only lists amps when using 12 VDC to actually cool the unit. I'll bet it's pulling at least 1 amp. Does anybody know?
Kirk

.9 amps in the normal mode and .4 with the hidden Climate Control switch "off" for my Dometic.

I have 3 group 27's and just completed a 6 day stint with NO hookups. I monitor the charge with a TriMetric monitor, phantom draw plus the fridge pulls me down 2% a day (that would be 6% on a single battery). I never got below 89% even with 2-3 hours of inverter driven TV/DSS. A two hour tow only got me from 89% up to 91%. A all day tow always got me to 100%.

A crappy solar panel added 2% back, keeping me topped off if I had a low usage day, otherwise I ran the Honda 2000i for an hour in the morning + one more in the pm to get to 100%.

[bovk]

Generator sounds like the best option. One question - if you charge by using the generator can it be too fast for the battery? How can it be controlled?

[SilverCottage]

Originally Posted by bovk

Generator sounds like the best option. One question - if you charge by using the generator can it be too fast for the battery? How can it be controlled?

I bit the bullet and bought a Progressive Dynamics 60 amp 12 V PD9260C RV Converter from eBay for $150 with free shipping. I had a bit of metal work to do on the old case and had to hard wire a plug so the new converter had a place to plug-in. The original one was hard wired.

You can read more about the converter at:
Intelli-Power PD9260C 60A Electronic RV Converter/Charger


Total swap took about 2 hours but I could probably do it in 20 minutes now

I now run my generator for 1 hour in the AM and 1 hour in the PM by plugging the AC cord on the trailer into the generator. Given the way the converter monitors the battery, I don't worry about overcharging the battery. I also carry a $5 hydrometer to measure the battery charge.