Battery dying while driving - questions
 

Hi - returned from a camping trip this weekend. We were on electric all weekend. When I returned home the battery was dead. Couldn't lift the hydraulic. I had the Fridge on 12V for the trip there and the trip back. A few "known items":

1) we got the battery with the camper this year. It's not that old but I don't think it has been maintained. It is losing all charge over the course of a week of sitting and I cannot lift the camper. Using an amp meter I cannot find a draw on the battery.

2) the inverter is no longer charging the battery. Validated with the amp meter. I have wired a battery maintainer into the 12V side of the inverter so it now charges when it is plugged in.

Would the fridge drain a lousy battery and the car not be able to keep up with a modest charge?

Anything other than the battery that I should be taking a look at here? We have a long trip coming up and I would hate to get to the end of the day and have a bad battery / not be able to lift the camper. I am thinking of getting a new battery, testing it half-way through the drive and if it's acting drained then I'll shut off the fridge and let the car charge the battery again. Will also have jumper cables. Just looking for thoughts.

You may have blown your battery charging fuse in the tow vehicle. You can test for charging voltage at the 7-pin plug with the engine running, or, with the trailer connected and the TV engine running I would expect to see maybe 13.5+ volts on the trailer battery terminals if the battery is being charged.

Once a battery is discharged, the vehicle alternator is not designed to recharge it. An alternator is only there to MAINTAIN a charge. The only way to safely recharge a dead battery is with a battery charger. Using the alternator can destroy it.

- Jack

The fridge will drain a good battery in a very short time, you must have a charging circuit from the TV, to the trailer battery, has to be #10 wire and a 30 amp fuse, ground wire must be # 10 also.
As Jack said you must use a 7 pin plug no adapters to 4 pin. Also if you don't disconnect the plug from the TV when raising the top the fuse in the TV will blow if the trailer battery is slightly discharged.

At the risk of being called a "smarta**" what you refer to as an inverter is really called a converter. It converts 110 volts to 12 volts, and in most cases charges the battery. An inverter is for converting 12 volts to 110 volts.

I agree with the above posts, in that, you are either not getting enough voltage/current through the TV supply line or not getting anything at all. Both are common problems. You can have bad connections, inadequate wiring, and/or a blown fuse in the TV.

PopRichie is right on with his post. Make sure you have a good battery. Take it to a auto parts store and have them check it under a load. If you have to replace it get the largest amp hr battery that fits. Make sure all battery circuit connections are clean. The lift pump pulls upwards of 100 amps and if the battery is low the TV charge fuse will blow and when you next travel you will get no charge from the TV. Unplug the power cord from the TV when lifting. What are you towing with and which model Hi Lo do you have. Most full size pickup should have a large enough alternator to charge your battery when traveling if you have a good battery, all wiring is the right size and connections are clean and tight. This applies to ground connections also.

Thanks all. The TV is a '97 Expedition with a factory tow package and 7 pin harness. The alternator was replaced about 2 years ago. The camper is a 21' FunSaver, 1986. Connections clean and tight will always be in question :)

I'll check out that fuse in the Expedition and take the camper battery in for testing as suggested. If I get a fresh battery for the camper and validate that there is current coming from the TV, the fridge should be able to run all day while I'm driving, right?

I'll make a note about disconnecting before trying to lift. I know I've not done that all the time - however I don't think there's an active +12V unless the ignition is on. Will double check that.

In my F150, the +12V battery feed is not active unless the ignition is ON, so I suspect your Expy is the same.

And, yes, assuming the wiring to the trailer plug is adequate (I think it is in Fords with the tow package), you should be able to run the refrigerator while driving. The manual for my trailer warns not to let the refrigerator run on DC power for more than an hour with the top lowered if not in motion. (It doesn't vent the heat as well to the outside with the top down, but you're going to pull a lot of battery power in this condition too.)

I have a "Watt usage meter" that I use in the "shore power" line, and when the refrigerator is running, it pulls something over 200 Watts (17+ Amps at 12 Volts) so that's going to drain a battery quickly.

- Jack

WOAH! That's a lot of juice!