Wiring guidance needed

[ajg617]

I installed Battleborns (well the dealer did but it was a mess so I completely re-wired), a Progressive Dynamics 9160ALV, BMV-712, Blue Sea, and pos/neg buss bars. When the Blue Sea is off, EVERYTHING is off with the exception of the hot lead to the BMV shunt. But this arrangement has some weaknesses and I'm adding additional disconnects but good gosh - how many does that make?

1) I would prefer the LiFePO4 battery heaters have a separate on/off CB as I found this winter we had some very cold days but most would warm up to the 20s or 30s and in the daytime sun I was very surprised at how warm the front compartment was when temps were checked. Typically I would only need the battery heaters for a few days at a time (and only for a few hours early AM until suns up for a bit). Since each will drain a battery in 40 hours, I'd like a little more control to be able to turn them on/off separately since the storage location has no 110v and the solar panel is covered with snow so might lose a little charge, but won't recharge. Then turn back on if the temps go below 0 to protect them. If extended below zero, I'd pull the batteries but trying to avoid doing that as much as possible.

2) The solar panel needs a CB before the solar controller. The rationale for adding a separate one is to add flexibility in allowing the batteries to discharge more substantially based upon DragonFly's guidance that it is not good for their batteries to stay topped off on continual shore power or solar. Even with parasitic draw, solar has kept the batteries topped off in marginal sun conditions -even cloudy days.

3) I'm still sorting out the breakaway switch issue that has been discussed on other threads and how to wire that switch directly so that it always has power even with the disconnect off.

It would be nice to leave the Blue Sea as is with only one input and one output for maintenance and battery removal purposes, but I'm not quite sure where else I could safely connect the three so they are on when the factory disconnect is on but off when the Blue Sea is off.

Thanks
John

[Jomani]

@ajg617
A couple of things. You mentioned the battery monitor shunt being on the “hot lead”. This should be on the negative side of the battery. On the negative side, everything should go through the shunt, then out to a bus bar or distribution center.

I am working on my setup now. The positive side from the battery goes to my Blue Sea disconnect switch. From the Blue Sea to a Victron distribution center (there are some good videos out there on how to add fuses to this one). I plan to keep the original battery disconnect switch and factory bus bar setup (for now at least). Positive from the distribution center will feed that bus bar. My thinking is that, with the Blue Sea Disconnect off, I will not be able to hook up to the trailer so there is little chance I will forget to turn it on prior to moving.

My emergency braking system is wired correctly so I won’t be changing that. For your battery heaters, you could connect a second wire directly to the input side of the Blue Sea disconnect, fuse it and run to a second switch. From the input side of the second switch, run a second wire to the emergency braking system - that way, the source is already fused and always hot.

On mine, both the solar controller and converter feed directly into the Victron distribution center so both will be fused there and on the downstream side of the Blue Sea disconnect. I will add a separate 2 pole DC switch (designed specifically for solar) between the solar panel and the solar controller. When the Blue Sea and the solar disconnect are both off, everything is dead.

[ajg617]

@ajg617
A couple of things. You mentioned the battery monitor shunt being on the “hot lead”. This should be on the negative side of the battery. On the negative side, everything should go through the shunt, then out to a bus bar or distribution center.

Thanks I should have been more clear. The shunt input connection is to the negative battery only and the output is the only feed to the negative bus. However, there is a fused shunt power wire which is directly connected to the positive terminal on the battery.

No Victron distribution center so that isn't a current option. The solar controller runs to the positive bus bar with a 30amp fuse but there is nothing on the panel side. I have a double pole CB for the panel side that I'll be installing, but I really want the option of leaving solar on when Blue Sea is off. I could connect the output of the solar controller directly to the input on the BlueSea but that kind of defeats the purpose of the BlueSea cutting everything off. Same is true for the battery heaters - just a lot of disconnects to juggle.

I'm guessing my breakaway is probably wired to the coach hot and un-fused as some folks found in https://www.mygrandrv.com/forum/show...d-at-the-coach . Not sure how I'm going to address that as I know the dealership moves the RVs around by lifting up the pin with a front end loader and leaving the jacks down - hence they moved mine with the jacks down and the Blue Sea off. I'd guess that they don't hook the breakaway up but who knows.

[Jomani]

Thanks I should have been more clear. The shunt input connection is to the negative battery only and the output is the only feed to the negative bus. However, there is a fused shunt power wire which is directly connected to the positive terminal on the battery.

That makes sense. As far as the emergency brakes, that circuit does nothing until the pin is pulled. When you pull the pin, it applies 12v to the brakes through a normally open switch.

Since I have a 12v refrigerator, my thinking on the solar is that I can turn on the Blue Sea disconnect and turn off the factory disconnect when I want to run refrigerator and solar. Without shore power, everything on the DC panel will be dead.

You have to keep in mind that every connector/connection point and switch adds resistance to the circuit. It also adds a potential for failure.

[Redapple63]

That makes sense. As far as the emergency brakes, that circuit does nothing until the pin is pulled. When you pull the pin, it applies 12v to the brakes through a normally open switch.

Since I have a 12v refrigerator, my thinking on the solar is that I can turn on the Blue Sea disconnect and turn off the factory disconnect when I want to run refrigerator and solar. Without shore power, everything on the DC panel will be dead.

You have to keep in mind that every connector/connection point and switch adds resistance to the circuit. It also adds a potential for failure.

Agreed. Items that are powered direct from the battery before the factory disconnect (at least on my rig) are emergency brakes, front jack (it’s a tt), bedroom slide, holding tank heaters, psx stabilizing jacks.

All these of those items except the emergency brakes are protected using auto reset circuit breakers.

You are correct that using two disconnect switches it is possible to isolate one charger or the other.

Bill