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Cola ny · 08-20-2014, 11:07 PM

Thanks mike & cha that's good to know👍

Cypressloser · 08-20-2014, 11:21 PM

The link that Skip provided gives you excellent information.
The first thing you should do is invest in a voltmeter to monitor the batteries, because every RV and RVer for that matter is different, there are a lot more devices drawing from the batteries than the fridge.
The state of charge chart (SOC) is important for the longevity of your batteries, so try not to drain them below 50% if possible, this can get pricey in a hurry.
You also want to learn about bulk charge, absorption charge and battery equalization to maximize their potential.
Charging the batteries through the generator is way more efficient than by driving the rv but even then it will likely take several hours to recharge them completely.

Murf2u · 08-21-2014, 06:27 AM

You don't say how far you drive to work, but a friend (construction worker out of town) in a similar situation.

He removed both batteries from the compartment and extended the cables slightly to allow them to reach the ground. He then connects just one battery to the RV and puts the other one in his passenger footwell connected to the power port. Driving back & forth then recharges the battery. Next day he takes the other one with him.

By using just one battery for one day they don't get run down too far and get recharged the next morning.

Gary RVRoamer · 08-21-2014, 09:44 AM

With just a day's use on the batteries and only the fridge, running the genset for 30 minutes would be plenty. But is that really the only power draw? What about lights in the evening, water pump for shower and washing dishes, maybe some other minor uses? They all add up. Maybe an hour on the genset?

Do you have any sort of meter panel that displays battery status? If not, how about using a hand held VOM to check house battery voltage. A fully charged 12v battery with no load on it should read at least 12.6v, but it will be higher if the charger has been running within the previous few hours. Maybe as high as 13.3-13.6v. If less than 12.6, run the genset longer.

Cola ny · 08-21-2014, 11:29 AM

Yes I do have a Control Panel which displays my batteries

Melmoses · 08-21-2014, 02:40 PM

If you have a battery control monitor then depending on what type, there is a wealth of information on that monitor you can use to determine what to do. Watch the monitor morning and again at night to see the current state of the batteries. Do not let them drop below 12.2V as lower than that will shorten the life.

By watching the monitor you can see how long your batteries go from a full charge to the 12.2 state. When they drop to 12.2, start your generator and monitor the panel to see how long before it reaches float charge. That tells you how long you must run the generator to keep the batteries going.

If you have the ability to set the generator auto start function, then set the generator to auto-start at 12.2 to keep the batteries from going down too low and you won't have to watch the monitor constantly to be sure to start it by the 12.2 level. Only downside to auto generator start is that it may start at any time so you may want to stop the auto start when you are not dry-camping or are camping in a place with quiet hours (no generator after 10pm sort of place).

As someone said, there are a lot of things besides the fridge drawing on those batteries: lights, tv, hot water heater, smoke detectors, etc. These all have an effect on how long your batteries will last before needing to be recharged. Just driving to and from work in it charges them from the alternator however, it won't be nearly long enough to fully charge the batteries. Only on day long drives will that work.

I assume you also are aware that you are limited on what will operate on batteries. You cannot run your microwave for instance as it has a huge power draw that will kill your batteries quickly. You cannot run your air conditioners either. On battery power, about all you can use are lights, television, hot water heater on propane, fridge on propane. Your wiring for your inverter/converter limits use of some things also. On generator you should be able to run anything you need depending on its size.

When we "dry" camp at the races, my procedure is to run the generator in the morning for a couple of hours while I have my coffee, turn on the air conditioners to cool us down, take baths with hot water heater on ac and not propane, charge the batteries to float status from the night and do all the things I want power for. Then I turn it off for the day and let the batteries take over. I turn it back on 1 hour at night again cool down the inside, cook in the microwave, recharge the batteries to float for the night, etc. During the day, we are out and about. That keeps my batteries in good shape. I can't use auto start at the races because of quiet times.

Just monitor your own normal daily usage of power by watching the batteries state of charge to see how long it takes to drop them to 12.2. Monitor how long you have to run the generator to get them back to float. Do this for a few days and you will have yourself a system to work with.

Cola ny · 08-21-2014, 08:25 PM

Sounds good thanks for your help

Don and Barb · 08-25-2014, 04:42 PM

Quote:

Originally Posted by Cola ny

I'm guessing my batteries recharge as i drive the unit as well am I correct

Yes, your batteries do charge as you drive but the alternator has a slow charge, so depending on how far you drive and how low the batteries are would determine if they would completely re-charge.