I Did Some Testing...

Bob Denman · 07-21-2019, 10:38 PM

... Of the two battery disconnect switches that I added to my batteries.
They actually work just like they're supposed to!

If I just set the switch to "Off" (We all know that doesn't do much...): at the end of the week, I'll be dropped from about 13.1 volts... to 11.9!

With both switches thrown: I'll still be at least at 12.7 volts!
Note: this pic only has one switch. I added a second one to the ground line coming in to the battery on the right...

http://www.thorforums.com/forums/att...1&d=1563748689

PAtrailtrimmer · 07-21-2019, 10:47 PM

Thanks. I bought a cutoff switch like you show in your picture. It will be installed during winterization later this year.

Bob Denman · 07-27-2019, 06:34 PM

UPDATE: Still at 12.6 volts this morning.

99dart · 07-27-2019, 08:00 PM

Good deal! Nice to know that the battery(ies) aren't going dead between uses.

**revjeffrey** · 07-27-2019, 08:17 PM

Well the difference is Bob's unit is not a Thor. On my 2017 axis 24.1 I can take the ground cable completely off BOTH HOUSE batteries throw them in the garbage and everything in my rig is still working will drain the batteries the next day I do have brand new batteries either my BIMM miswired BY Thor something else I cannot figure out. I guess my question I would like to know if any other Axis orVegas owners can take the ground cables off of their house batteries and still have everything running. I now whenever I park disconnect the house and the chassis battery positive. I hope someone can give me a clue of what's going on thank you. I also seem to believe my emergency start on the dash has never ever worked.

**16ACE27** · 07-27-2019, 08:48 PM

Quote:

Originally Posted by revjeffrey

Well the difference is Bob's unit is not a Thor. On my 2017 axis 24.1 I can take the ground cable completely off BOTH HOUSE batteries throw them in the garbage and everything in my rig is still working will drain the batteries the next day I do have brand new batteries either my BIMM miswired BY Thor something else I cannot figure out. I guess my question I would like to know if any other Axis orVegas owners can take the ground cables off of their house batteries and still have everything running. I now whenever I park disconnect the house and the chassis battery positive. I hope someone can give me a clue of what's going on thank you. I also seem to believe my emergency start on the dash has never ever worked.

Gotta see this to believe it. If there is no connection to the negative side of the battery, the battery can neither be charged nor discharge: there is no path for current flow through the battery. If this is indeed the case and the battery goes dead then you have a bad battery.

**revjeffrey** · 07-27-2019, 09:04 PM

I wish I lived closer, I would drive it by. Both negative off House everything in house still energized. Lights etc.

**16ACE27** · 07-27-2019, 09:09 PM

Quote:

Originally Posted by revjeffrey

I wish I lived closer, I would drive it by. Both negative off House everything in house still energized. Lights etc.

Without being plugged in? If NOT plugged in pull the negative off the chassis battery as well and see what happens.

**revjeffrey** · 07-28-2019, 12:40 AM

I will head to the storage unit in the morning and a try that out. And let you know the results.

Chance · 07-28-2019, 01:41 AM

Do you have solar?

Depending on how it’s wired, 12V can also come from converter, solar, alternator, or chassis battery.

**revjeffrey** · 07-28-2019, 01:57 AM

No, I do not have solar in fact my unit is stock no additions. I was hoping to see if other Axis or Vegas owners disconnected there negatives also and got the same results. I am suspecting my BIMM (pictured) has been miss wired from the Thor factory from day one.

mstng · 07-28-2019, 02:38 AM

Quote:

Originally Posted by revjeffrey

No, I do not have solar in fact my unit is stock no additions. I was hoping to see if other Axis or Vegas owners disconnected there negatives also and got the same results. I am suspecting my BIMM (pictured) has been miss wired from the Thor factory from day one.

That’s crazy Rev. I’ve got some battery maintenance to do tomorrow and will pull the ground cables on my 2018 24.1 and pass it on.

**revjeffrey** · 07-28-2019, 02:42 AM

I would appreciate that. Could give me a start for a final repair solution.

mstng · 07-28-2019, 05:17 PM

RevJeffery,

Pulled cables off both negatives and lost all power. Hope this helps some how.

Built 18 months ago and luckily house batteries still going strong. Minimal boon docking but did stress test it for 24 hours with fan, lights etc. Been unlucky in other ways though. Let us know what you find.

Bob Denman · 07-28-2019, 05:48 PM

As I said earlier: I did install a disconnect on the input side's ground also...

**revjeffrey** · 07-28-2019, 09:52 PM

I'm thinking of switching around the two big positive wires on my Bimm but I'm afraid I might short something out but I'm not sure what else I could do. now that I confirm that mine is messed up. I am going to call that company tomorrow and ask them what would happen if I switched it to cables. Thank you for checking for me that helps tremendously.

**16ACE27** · 07-28-2019, 10:06 PM

Quote:

Originally Posted by revjeffrey

I'm thinking of switching around the two big positive wires on my Bimm but I'm afraid I might short something out but I'm not sure what else I could do. now that I confirm that mine is messed up. I am going to call that company tomorrow and ask them what would happen if I switched it to cables. Thank you for checking for me that helps tremendously.

I assume that when you lifted the negative on the chassis battery your lights went out? If so, either your BIM is not isolating the two battery banks as it should or your chassis battery is wired to the house DC buss directly (and who knows where the house batteries are wired to). Since the BIM is supposed to isolate the two circuits (House and Chassis) when no charging is going on, swapping the big positive wires will not accomplish anything. If you were going to do some swapping you would have to swap the sense wires as well.

At this point I would leave all battery negatives disconnected, lift one big positive off the BIM and check for continuity between the two large posts. There should be none. If they are connected in this state, the BIM is bad (shorted) and needs to be replaced.

mstng · 07-28-2019, 10:59 PM

Rev, help me find my BIM on this 2018 and I’ll snap a pick if that will help

Bob Denman · 07-29-2019, 11:32 AM

Quote:

Originally Posted by Bob Denman

As I said earlier: I did install a disconnect on the input side's ground also...

Updated photo:

http://www.thorforums.com/forums/att...1&d=1564399954

K0LCB · 07-29-2019, 01:42 PM

Quote:

Originally Posted by Bob Denman

... Of the two battery disconnect switches that I added to my batteries.
They actually work just like they're supposed to!

If I just set the switch to "Off" (We all know that doesn't do much...): at the end of the week, I'll be dropped from about 13.1 volts... to 11.9!

With both switches thrown: I'll still be at least at 12.7 volts!
Note: this pic only has one switch. I added a second one to the ground line coming in to the battery on the right...

http://www.thorforums.com/forums/att...1&d=1563748689

Did you look under dash, above accelerator pedal, for a disconnect? I believe that is a factory install on Sprinters.

You may also like: