Charging The Battery

[Steve_Guelph]

Going back to a B from a Travel Trailer lead to a few questions. If the battery disconnect is "off" while I am driving will the battery still charge?

When dry camping how long do I need to run my Gen to charge the battery back up. I know it depends on how low it is so let say it is 60% full.

In the winter if I exercise the gen for 2 hours a months is that enough to charge the battery or should I still plug the B in to shore power for recharging?

Thanks...Steve

[markopolo]

Yes, your house battery should still get charged when driving your RV even with the battery disconnect in the off possition. Most B's have both an isolator and a battery disconnect. The two battery banks are joined via the isolator when the motor is running. The battery disconnect separates the "house" from the house battery so your fridge etc. won't run on 12v when the battery disconnect is off.

Re: recharging via generator - lots of variables there. You need to know your charger output and if it is a 3 stage or just a basic charger. If it is 40amp hr and and your 120amp hr battery is 60% depleted then, in theory, you'd recharge in about 2 hours. It doesn't actually work as efficiently as that because the charge rate tapers off the more charged the battery becomes.

Lots of RV'ers either disconnect their batteries or maintain them by running the generator when in storage. I prefer to keep my RV plugged in all year long. My setup keeps both the house and chassis battery fully charged all the time. It's just a float charge. A fully charged battery if a happy battery. I wouldn't keep them charging all winter if you only have a basic charger but if you have a smart charger or 3 stage charger then I would.

[Steve_Guelph]

Thanks Marco.

[Mike]

Hi Steve,
My 2002 Chev Roadtrek 190P talks about the charging system like this (from the owner's manual)....

"AUXILIARY BATTERY AND ISOLATOR:
The auxiliary battery is a group 27 lead acid battery. The auxiliary battery is located behind the
passenger side access door found behind the rear wheel, see Picture B-P27. To access the battery refer
to the auxiliary battery section found in the daily living area.
The auxiliary battery is automatically charged through the isolator by the engine's alternator while the
engine is running. This battery is also automatically charged by the converter / charger when:
1. The battery disconnect switch on the monitor panel is set to the “ON” position prior to connection
to an outside electrical power source.
2. Your vehicle is connected to an outside electrical power source.
3. The breakers in the converter/charger are in the "ON" position.
4. Or while the generator is in operation (if so equipped).
A disconnect switch, located on the monitor panel, provides a disconnect for the auxiliary battery from the
12V system while your vehicle is not in use.
Since the auxiliary battery is a deep-cycle type, it may be discharged completely and recharged without
damage (whereas the automotive battery is designed to be kept fully charged by the alternator and may
undergo damage if fully discharged). However, a battery should never remain in a discharged state and
should be recharged immediately to prevent damage. When not in use, the auxiliary battery will slowly
discharge on its own.
Accordingly, if the battery is not being used, it should be recharged monthly by connecting to an outside
electrical power source, by operating the generator (if equipped) for at least 12 hours, or by running your
vehicle’s engine for a minimum of 2 hours.
The isolator is located under the hood in the engine compartment. The isolator allows the alternator to
charge both the automotive and auxiliary batteries when the engine is running, and it will prevent your
vehicle's 12V motorhome equipment (interior lights, water pump, exhaust fans, furnace blower, etc.) from
drawing on the automotive battery."

SO that's how mine works. There should be a section in your manual with model/year specific details.
Another factor might be the type of battery (lead acid, AGM, etc. ) and battery capacity. More capacity
would probably take longer to recharge, but one would hope you'd get more run/draw time from it too.