Chassis Battery Cutoff Switch

[rfsod48]

When storing our mh in winter the chassis battery looses charge. There is a shutoff switch at the door I turn off but doesn't seem to make any difference. When the roads are clear I go out and drive mh 50-75 miles. Problem is that here in Michigan we normally have snow.  I have a cutoff switch for house batteries and wonder if I should get one for chassis batteries. Coach is stored without any electrical hookup.

[wayne77590]

Turn off the step. There is a constant draw on the step motor using a current limiting switch.  The drain is over 2 amp and will drain down the battery.  Get a full charge and when you leave the MH in storage turn off the step motor.

My step switch is just inside the door and I can turn it off with a 12-15 inch piece of anything after closing the screen door and reaching inside..

My battery would go down to 11 volts in just a few days when the switch was left on and I have 110 power to the MH. The Trik-L-Charge could not keep up.  Do you have a solar panel for charging?

[wolfe10]

While some coaches do have a chassis battery cut off switch (our 2003 Alpine does) they are not common.  You could install one or merely remove the negative terminal of the chassis battery when in storage.

[rfsod48]

If you do cut off chassis battery will you have trouble with the engine computer/transmission? 

[wolfe10]

10 minutes ago, rfsod48 said:

If you do cut off chassis battery will you have trouble with the engine computer/transmission? 

While that is possible, it is less likely than if you allow chassis battery voltage to drop below "operating voltage".

Said another way, allowing the chassis battery to go dead and then jump start would be harder on the electronics.

Yes, best is that battery voltage is good and electronics are connected. That means either solar (keeping snow off the panels) or shore power or more frequent drives than is probably reasonable in your area.

[rfsod48]

Thanks for the help! Perhaps the best solution is for my wife and I to leave earlier to head southwest. 

[dickandlois]

Roland, Not knowing the setup you have for storing the coach. I have been impressed with the ability of solar panels to maintain the charge. The price has come down and placing them so they face South and even hanging vertically to keep the snow cover to a minimum and no direct sunlight, just the flat light of a cloudy day. They can provide over 12.5 volts. The current flow is less, but with a little calculation work, one can get a good result with out braking the bank and keep batteries charged.

Rich.

[rfsod48]

Rich,

I have seen some solar panels that can be plugged into a cigarette lighter receptical. If that receptical is live from starter batteries could this be a system to maintain charge? I park outside and with our snow, a panel I could hang would be ideal. For this purpose would 10-15 watts be sufficient?

Thanks,

Roland

[dickandlois]

52 minutes ago, rfsod48 said:

Rich,

I have seen some solar panels that can be plugged into a cigarette lighter receptical. If that receptical is live from starter batteries could this be a system to maintain charge? I park outside and with our snow, a panel I could hang would be ideal. For this purpose would 10-15 watts be sufficient?

Thanks,

Roland

Roland, Like many things there is always a catch 22. The 12 volt lighter sockets are connected to only the chassis batteries in most cases.

The key here is to check and see if your coach is equipped with a battery Isolator. It is a device that charges both battery banks from the alternator or the inverter / charger. If it is, to keep the coach and chassis batteries one would need to feed the power from the solar panel to the common point. 

The second option is to connect the panels to the alternator output, because when running the engine it does charge both banks in some manner and they are other wise separated so that if the chassis batteries will not start the engine, one can engage a switch to connect the coach and chassis batteries for starting the engine.

Regarding the size and because of your location panels supplying 20 to 30 watts might be a better choice. That would increase the charging current and that will sure help and remember positive to positive / negative ti negative. 

You can use a volt meter or better yet a battery hydrometer to see if they are maintaining a good specific gravity. If the level is in the green you are doing just fine and if the reading is low. Remove the jumpers(Always good to have some pictures or a good drawing before removing wires)and check the voltage of each battery. one of them is not in the best condition and is eating current, limiting the charge level of the others batteries.

If this makes you feel uncomfortable ask for help and ask to be tortured, none of us have all the skill sets when working on a motorhome.

Rich. 

 

[rfsod48]

 

If my main goal is to maintain charge in the starter batteries do I need to hook system up to inverter charger? Renogy has a system and connection diagram has optional connection to converter as well as battery. It is a 100 watt system.

[wolfe10]

15 minutes ago, rfsod48 said:

 

If my main goal is to maintain charge in the starter batteries do I need to hook system up to inverter charger? Renogy has a system and connection diagram has optional connection to converter as well as battery. It is a 100 watt system.

You will need to consult your wiring diagram to see where you can connect to charge chassis batteries and/or house batteries. 

There is no industry standard-- on many, the inverter/charger does not charge the chassis battery.

If you do not have a wiring diagram, contact Fleetwood with the question.

 

[kaypsmith]

If you store the coach on the outside, there is also a small gasoline generator charger that hooks directly to the battery bank. The built in electronics monitor the charge of the batteries that it is maintaining and when they fall close to the lowest level that it is set to maintain, it will start off of the batteries that it is maintaining and run until ample charge has been achieved. It is a little pricey, but works very well.

[rfsod48]

Thanks all for the help. After talking with the folks at Renogy and going thru my current system I ordered a 100 w panel and controller, it is expandable if I should want to add more panels. Again thanks for the input. 

Roland 

[five]

13 hours ago, wolfe10 said:

 

...There is no industry standard-- on many, the inverter/charger does not charge the chassis battery...

 

True.  To add to the confusion, my inv/charger will charge the chassis batteries only after the coach batteries are charged and the charger is putting out at least 13.3 volts.  Any charge less than that and the chassis batteries will not get charged.

[wolfe10]

55 minutes ago, FIVE said:

True.  To add to the confusion, my inv/charger will charge the chassis batteries only after the coach batteries are charged and the charger is putting out at least 13.3 volts.  Any charge less than that and the chassis batteries will not get charged.

 

Sounds like you have one of the "smart thief" devices such as a Xantrex Echo Charger.  A very common and perfectly acceptable methods of maintaining chassis battery charge.