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Battery Disconnect Switches

When not on the road, we are now parking in a covered RV storage yard that does not have any hookups at our site.  We used to park out in the open where our roof solar kept battery banks under charge.  But with the upgrade to covered we needed to make changes to help our batteries stay charged.  We decided to install high-amp disconnect switches.

For the house battery bank, we installed our recently-removed door step 'salesman' switch.  Removed main negative cable, attached it to the salesman switch and then put a new short cable between switch and negative battery post.

The engine start battery bank is different as I did not want to put a disconnect on our starter circuit, as every disconnect could be a weak point with very high-amp momentary loads. 

We bought a Blue Sea 300-amp m-series switch from Amazon for our start bank disconnect.

Foretravel has a dedicated positive cable from battery directly to starter solenoid, which we could leave in place.  We put a disconnect switch on another cable that connects battery to boost solenoid.  When switch is off, all power including voltage to activate starter solenoid is removed.

Our boost solenoid cable was re-located from start battery to Blue Sea switch, and a new short cable was installed between Blue Sea and battery.

We also had two small wires on our start positive post that I disconnected.  One was for alternator voltage sense and the other was to a kitchen start battery volt meter.

I am curious to learn without any loads how much the batteries will self-discharge.


Re: Battery Disconnect Switches

Reply #1 –
About 5% for a lead acid battery with a clean dry top.  Dampness between terminals will increase rate.

Keith
Keith, Joyce & Smokey the Australian Cattle Dog
1995 U320 SE Extreme 40' WTBI Build # 4780, with a Honda CR-V hopefully still following behind.
Motorcade # 17030
FMCA # F422159

Re: Battery Disconnect Switches

Reply #2 –
My nearly 18 year old original 8D Gel battery that now powers my electric chainsaw out in the woods ... Repurposing Old Stuff, The Long Life of a Gel Battery. ... charges up for a couple days on a smart 4 stage charger and then with only a digital voltage display hooked up will hold charge for months at a time maybe losing 0.1 or 0.2 volts.  If you truly isolate a fully charged battery they hold charge for a long time.  If it is below freezing like it is here in MN (only in the winter) they should get moved indoors or be on a smart charger.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Battery Disconnect Switches

Reply #3 –
I disconnect the negative cable for the chassis battery when in storage and leave the house batteries connected and turn off the salesman switch.  That seems to work okay for me with just driving the coach once a month.  There is a little bit of drain on the house batteries, not sure what it is, maybe the dash clock as the refrig and every thing else is off.
Jerry Whiteaker former owner 96 U270  36' #4831 Austin,TX-Owner Mods LCD TV w/front cabinet rebuild - LCD TV bedroom - Dual Central AC, either can cool coach w 30 amp - Skylights at roof AC openings - Drop ceiling for ducting of AC - Shower skylight white gelcoat/wood/epoxy frame - Air Springs/Shocks replaced - 2014 CRV - 8K Home Solar - Chevy Volt

Re: Battery Disconnect Switches

Reply #4 –
Jerry, the salesman switch turns almost everything off EXCEPT for half of the bay wall breakers for fridge and detectors.  Pretty easy to relocate the fridge, etc feed wire so all is turned off with the salesman switch.