Community Forums

CoreyinWP · 09-10-2018, 06:50 AM

Looking to install a batter disconnect on my Ventana. From my reading here,

1. it should be installed on the positive side.

2. I should use this https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 for the disconnect.

3. I have two lines coming of positive,,,one to the house and one to inverter.

If all this is true, do I just get jumpers for the two lines and put both of the lugs on one post on the disconnect?

Any advice and /or comments are much appreciated.

twinboat · 09-10-2018, 07:40 AM

I would get the 1-2 switch and put the house feed on #1 and the inverter on #2. It gives you the option to shut down one or the other or both.

Make sure the cable coming from the switch common post and going to the battery is heavy enough to carry the loads of both house and inverter.

Quincy · 09-10-2018, 08:36 AM

If the purpose of the disconnect switch is just for storage then the easiest install would be on the negative terminal. Only one wire to worry about and no chance of any other parasitic loss. The positive terminal sometimes has multiple wires and owner added items so it becomes a more difficult endeavor. JMHO

twinboat · 09-10-2018, 10:05 AM

Quote:

Originally Posted by Quincy

If the purpose of the disconnect switch is just for storage then the easiest install would be on the negative terminal. Only one wire to worry about and no chance of any other parasitic loss. The positive terminal sometimes has multiple wires and owner added items so it becomes a more difficult endeavor. JMHO

Except that Magnum recommends disconnecting the positive cable on some of there inverter/chargers.

C.Martin · 09-10-2018, 11:37 AM

Quote:

Originally Posted by twinboat

Except that Magnum recommends disconnecting the positive cable on some of there inverter/chargers.

Exactly what twin boat said.

I have solar, so the only time I shut things off completely is to clean the battery tray or swap out components. If you want to completely shut down the house batteries ->->->->->->->

++++++This applies to RV's with a Magnum Energy Inverter like the MS2812...that has network devices connected such as the ME-AGS, ME-BMK. Reason being...the MS2812 doesn't use isolators on the network connection. So, if you remove the MS2812's negative lead...it will seek a new pathway thru these sensitive network devices and scramble their brains.++++++

So,

First...Disconnect the POS to the inverter. I put a big hi-amp red switch on the inverter positive right by the catastrophic T-fuse.

Second...disconnect the negatives to the battery bank. If you've installed a shunt for a battery monitor...it will be just one lead. I would put another hi-amp switch to the batteries w/ a single 4/0 conductor, if I intended on shutting down the bank routibely...

Hope that made sense...

So...a single short 4/0 jumper to the T-fuse...the 350A switch you show will work...I would add some form of insulator between the bare poles on the switch and the sheet metal on the Ventana.

And place all of the Negative leads...from your battery bank (House, Frame, Inverter (as labeled on the decal legend)) to one side of the negative disconnect switch...and a single 4/0 cable going from the other side of the disconnect switch to the battery bank. Good time to think about installing g a battery monitor if so desired.

CoreyinWP · 09-10-2018, 12:54 PM

Thanks Charlie for the picture. Any chance you have one for the ground side and the BMK? I will take your suggestion and install that as well.

CoreyinWP · 09-10-2018, 01:03 PM

Just found your pics on the bmk install...thanks

C.Martin · 09-10-2018, 01:36 PM

Quote:

Originally Posted by CoreyinWP

Just found your pics on the bmk install...thanks

I don't know if I updated them.

Anyway, a scrap cut from an old cutting board made a nice mount which could be attached using a bolt thru an existing hole thru the frame rail. The big cable on the left is the battery side 4/0. You could put another disconnect switch on that side. The other side of the shunt is all the grounds, which required a slightly longer bolt than the one supplied with the shunt. There are four big cables there...Frame, House, Inverter, and Solar.

In my original installation, I used the shunt from the ME-BMK kit. Later, I wanted to add temperature compensation and remote monitoring to my Victron Solar system...So, I added the Victron BMV-712 battery monitor too. If you only install one...the ME-BMK is the way to go, as it can be read from your Magnum remote. It also can add additional features if you also upgrade the remote to a ME-ARC remote. If you know for certain you want Solar with remote monitoring...then I would recommend the BMV-712 and ME-BMK-NS. The -NS is the Magnum kit without the shunt. You can connect the Magnum sense wires to the Shunt that comes with the Victron BMV-712...but not the other way around. Overkill...but we have all the added features for our Magnum Inverter and auto gen start that you get by having a SOC (State of Charge) input....along with remote monitoring of my DC electrical system and Solar thru the Victron setup.

CoreyinWP · 09-10-2018, 07:37 PM

Thanks again Charlie. I can put the disconnect to the left of the shunt on the single wire?

C.Martin · 09-11-2018, 05:11 AM

Quote:

Originally Posted by CoreyinWP

Thanks again Charlie. I can put the disconnect to the left of the shunt on the single wire?

That would be the easiest way... the other side would mean putting a stack of lugs on the back of the switch. That would make it much more difficult to connect for sure.

The shunt orientation is really up to you. Battery connection goes on one side...all the Load connections go to the other. With the ME-BMK kit...the “blue” sense wire goes on the battery side and the “orange” wire goes in the load side.

It’s best to have the coach where you can plug-in after the job is done. When the charger gets to absorb voltage and holds that for a certain amount of time, the Batery Monitor establishes it’s 100% reference point. Until that is accomplished it will just say “learning”. So, being able to do a full charge is necessary.

IIRC the existing frame ground was just under 5’ long...and was secured overhead with zip ties. I purchased a 5ft section of TEMCO 4/0 welding wire to make the single lead from the shunt to battery bank. I cut it down a bit to prevent using more wire than necessary and crimped the correct sized lugs on the ends. You should have a bit extra...which you can use to tie the switch to the shunt.

Use caution climbing under the rig. I lifted the front with levelers for clearance and moved to a location between the fuel tank and dash a/c condenser and condenser fan housing. There’s a big place to sit under the coach there with good clearance. Take a phone...if for some freak occurrence the levelers leak down...unless you’re super slender... I’ll just say —- it wouldn’t be possible for me to climb back out without someone lifting the coach first. This location gives you good access to the frame rail. If you reach across the batteries..make sure to throw old ponchos or something across the tops of all those terminals, if a metal object touches the wrong thing...you’ll be doing some arc welding without really meaning to.