What's That Big Switch?

[sjpotter]

As I enter the coach (2005 26' RB) there is a big rotary switch on the left side pantry outer wall. It looks like a marine style battery switch. What does this switch accomplish. I can not find an answer in the owners manual. I bought this coach used a couple months ago

Thanks.

[whemme]

That rotary switch is your coach battery's master ON/OFF switch. When in the OFF position your batteries are isolated and no longer connected to either the charging output of your Parallax 7345 Charger/Converter nor are the batteries connected and supplying DC power to all of the DC appliances in the coach. However, if you are plugged into shore line AC power or you start your generator, the DC appliances will still work because they are then receiving DC power from the 13.8 vdc output of your Parallax 7345 Charger/Converter.

Normally you would shut that switch OFF whenever your coach is in storage so that parasitic loads such as your LP gas detector won't discharge your coach batteries over time. You should also shut that switch OFF whenever you are in a campground plugged into shore line power for more than 2 days because when the charger/converter has topped off the charge of your batteries any further changing will result in over-charging the batteries, resulting in boiling out the acid/water mixture and causing damage to the batteries.

[sjpotter]

good info, thanks much. I see you're a pilot, me too, or at least I was.

[mockturtle]

I suggest everyone read up on it's proper operation located somewhere in the Born Free Owners Manual.

Most importantly, when not to turn the dial.

Sam, my manual is not very specific other than instructing to turn the switch to 'off' for storage. Could you elaborate on 'when not to turn the dial'?

[oliverpsmile]

The switch is ON when
- dry camping
- recharging
a. from the engine
b. from the generator
c. from a hook up in RV park - caution:
you can overcharge and destroying the batteries
if your 12 VDC converter supplies 3 amps all the
time. There are some modern stuff (see Bill
Hemme's modifications in the Coach Modifications section)

Personally, when on hook up my switch is always OFF. If I dry camp the batteries will be recharged by the engine on the way to camp. Of course OFF position when in storage.

This post editied by bfadmin-2 on August 19, 2011.

[Dave&JanPotter]

I suggest everyone read up on it's proper operation located somewhere in the Born Free Owners Manual.

Most importantly, when not to turn the dial.

Sam, my manual is not very specific other than instructing to turn the switch to 'off' for storage. Could you elaborate on 'when not to turn the dial'?

My BF Owners Manual stated:
DO NOT TURN THE ROTARY DIAL TO THE OFF POSITION WHILE COACH ENGINE IS RUNNING

I believe this caution is added to the manual so that the alternator fields are not damaged when the dial is switched off while under load. In the marine field which uses this same type of switch, it happens enough that they make a set of diodes that can be wired into the circuit to prevent damaging the alternator if the switch is mistakenly used in this way. Also, some alternators are protected against this by design and there are switches that prevent this problem by design that can be substituted for the one BF installs.

[jasper2222]

Well, we have turned on our off/on many times while the motor is running. Glad I now know better. Anyone with any ideas on a good switch (with the diodes built-in) that I could switch out with.



Richard

[Dave&JanPotter]

Well, we have turned on our off/on many times while the motor is running. Glad I now know better. Anyone with any ideas on a good switch (with the diodes built-in) that I could switch out with.



Richard

Without researching the alternator model I can't tell you if you are susceptible to this problem or not. A good marine supply store should be able to help you, someone like West Marine, and they are online at westmarine.com. Search for Perko battery switches although you may have to do some digging as many of the switches will be for the dual starting battery setup that the marine field uses.