Battery Isolator Switch

[Frank111]

I have a question for you electrical wizards. I have a 2007 Winnebago Sightseer (30ft). I like to keep it plugged in at home to keep the refrigerator running so we can take-off when we want to, however I don't like the batteries being constantly being charged while the coach is plugged in. I check the battery fluid levels every week or two and add disitilled water if necesssary. My question is , if I turn off the Aux Battery Switch, will that prevent the coach and vechicle batteries from being constantly charged? I have the wiring diagrams, however, reading them and decyphering the information is beyond my capabilities. If we can't get a definitive answer here, I guess I'll give Winnebago Industries a call. Thanks for your help, this is a great forum for information on the RV and RVing.

[bdaball]

You would always be best served by seeking that information directly from the factory. Be sure to have your serial number and coach number handy when you call.
It is always possible that there might be different configurations within the same model based on how the unit was originally ordered and what style equipment was included.

[Roadking]

What brand convertor/charger is installed in your coach? Most of these units will not over charge or damage your batteries. Isn't there a charger/convertor on/off switch on the invertor remote control panel that is located in the power management panel?

Not familiar with your coach but on my Winny the Aux battery disconnect switch will disconnect the coach batteries from the various 12VDC circuits in the coach, however, the charger remains connected and thus if the charger is on it will charge the batteries even with the aux bat switch off. My aux bat switch has NO EFFECT on the engine/chassis bat.

[MrTransistor]

Hi Frank,

If there are disconnects for the two battery sets, they will be separate devices. The one for the coach will generally be a remote switch by the entry that controls a two position contactor fairly close to the batteries. From the control switch, press one way and the contactor will close then stay there when switch is released. Press the other way and its contact will close then stay in that position when control power is removed.

The engine battery disconnect is a different setup. If installed it will probably be a manual switch device with large connections and very heavy contacts that is rotated to the off position. When off, the engine disconnect removes the residual drain caused by all the computers on a modern chassis. This can amount to 1 to 2 Amps. and can drain the engine batteries in 1 to 2 weeks especially with the Freightliner diesel powered coaches. Bear in mind that flooded lead acid batteries will loose 10 to 15% per month through normal internal self discharge. This amounts to something like a quarter Amp.

This same internal discharge applies to the coach batteries if they are flooded type. You can moderate this to some extent by using AGM batteries that have less than 2% per month self discharge. Add to that all of the coaches residual loads like the refrigerator, the OnePlace control unit and panel, converter standby load, bedroom radio, propane leak detector, miscellaneous battery chargers, and etc.

Therein lies the reason for disconnects or being plugged in to maintain a float voltage on the system. Also remember that unless something like an ‘Echo~Charge’ or ‘Trik-L-Start’ is installed, there will be no charging of the chassis battery.

If your inverter, charger, or converter is working properly and producing a good float voltage of 13.2 to 13.8 Volts, and you have something like an ‘Echo~Charge’ connected, you should not worry at all about being plugged in 24/7 while in storage. Unless the float voltage is above 13.8 Volts, you shouldn’t need to top off the batteries but maybe every other month. If the voltage were to creep (usually caused by a malfunction of the charger) up to say 14.8 volts, the batteries will boil away the water in the cells at a pretty fast rate. This kind of voltage can kill a battery in as little as a week

Get a good accurate volt meter, install a Trik-L-Start if it’s not yet there, check the voltage at the battery terminals when you are plugged in, and if all seems normal, sleep with the knowledge that the coach is doing well and the batteries will be ready to go for your next trip.