Battery Monitor Location

[pmglidden]

I am going to install a shunt based battery monitor in my 2306BHS. Has anyone else put a battery monitor in their micro?

Where did you install it?

Have people tried to fish wire to the location with the factory switches and monitor? The other location I was considering is just in the pass through storage area.

Other thoughts?

[pmglidden]

Any ideas here? Is anyone using a battery monitor in their micro minnie?

[Goodspike]

I've not done it, but I would think someplace further forward would be a lot easier.

[MicroMinnie]

As goodspike mentioned the more forward the easier it is very hard to get very accurate readings on lead based batteries from the $25 or so shunt based systems out there btw, so buy a good one.

In doing a similair project I could not find a way to get to the back without opening the bottom of the trailer up or drilling through the front, decided against that.

But...I do have an idea.

The victron BMV 712 ($200) has bluetooth, so you can run their app and forget about the wiring all together. just a thought. mount it all in the battery box.

[Goodspike]

Originally Posted by MicroMinnie

The victron BMV 712 ($200) has bluetooth, so you can run their app and forget about the wiring all together. just a thought. mount it all in the battery box.

How do I send the opposite of a thank? You just gave me something else to buy!

Is there some reason that needs to be on the negative side? I was thinking that if you could hook it up on the positive side you could connect at the shutoff and wire from there, which on mine is in the front storage compartment. I guess with the BT it doesn't matter much, but it would be nice to easily see their dial device.

The disadvantage to my thinking though is I couldn't include the power tongue jack in the power drain.

[MicroMinnie]

Haha, there’s never an end to it!, always something new or better.

As for shunts on the negative side, it’s quite common but here’s victrons explanation:

It is in the negative side so the the Voltage drop measured over the shunt will be a positive value with respect to the negative of the battery.
The Analogue to Digital converters (like what's in the BMV unit) need to measure a positive Voltage with respect to it's digital ground which is referenced to battery negative.

[sreckner]

When I installed a Victron BMV in our Aliner aframe, I installed the shunt in the negative from the battery just before it entered the WFCO Power Center. That eliminated having to run a wire for the display all the way from the front to the spot near the back of the trailer where I wanted it. I'm hoping to be able to do something similar in the 1708FB we're picking up next week and mounting the display with the other controls just inside the door at the rear.

[pmglidden]

I have been considering the victron but it’s seriously pricey. Although if I got that unit I could mount it in the front pass through storage somewhere.

On the 2306 the power for the slide doesn’t go through the battery switch as well, so I don’t know if I could get away with putting it near the panel.

[DaKevster]

I installed a Victron BMV-712, and mounted the display in the battery compartment for now. Given the bluetooth remote and phone app are so good, I saw no compelling reason to work out how to fish cable to mount in cabin. I just took some scrap plywood and built up a raised platform and cut a hole for the control unit. Pic here https://imgur.com/a/dlTrRqL

[creativepart]

Lots of folks install the Victron in a compartment near the batteries and hide it away only using the bluetooth for monitoring.

I have Magnum Inverter, so I got a Magnum BMK. It plugs into the inverter and you can read it inside the RV on the Inverter's remote display. It's nice to have it, but I really would rather have it on my phone.

I have a Victron solar charge controller and really love having that app for monitoring the system (there is no other display for the Victron solar controller, by the way).

I'm seriously considering removing the Magnum BMK and changing to the Victron BMK solely for that bluetooth display.

[Micro1808]

In my 1808, I surface mounted a small wooden box with a hinged lid ($6 at a hobby store) to the wall of the cabinet facing the bed. In that box, I mounted 2 bayite $18 monitors. Using some 7 wire irrigation wire, fished it down thru the cabinet, over to the front storage compartment--only about 3 feet away. From there, a foot or two over to the batteries I moved inside the front storage area.

Having it there kind of keeps it out of site, and lets me monitor the batteries while in bed. Just for fun, I threw in a low voltage alarm with a kill switch. Now I can monitor how much juice I burn each night, and how much I can recover with my solar panel during the day.

[Out N About]

I've just installed a Victron BMV-712, and have one wiring question. On my current battery bank (two 12v wired in parallel), the chassis ground and the positive feed are connected on the diagonal posts of the pair, in agreement with the wiring diagram and as confirmed as preferable in other posts. My charging cables, however, are both connected to a single battery. Should I move the negative charger cable from the battery to the shunt as well, as it appears that the BMV-712 can't see the current going back into the batteries?

[MicroMinnie]

Yes for sure. needs to be on the shunt “loads and chargers” side, not the battery post, also the shunt is directional on certain Victrons, but if you see the load going out on the display you have it the right way.

[creativepart]

Originally Posted by Out N About

Should I move the negative charger cable from the battery to the shunt as well, as it appears that the BMV-712 can't see the current going back into the batteries?

I'm not sure I understand what you are asking. So let me answer generally.

ALL load negatives (chassis, inverter/charger or converter/charger, solar charge controller) need to go to the LOAD side of the shunt. Then you run a neg cable from the power side of the shunt to the battery.

I was not able to run all my neg loads to the load side of the shunt because of how thick the cables were. I could have changed out the load side post (a bolt) to a longer bolt and made all 3 of my load negs fit on the one post. But instead I installed a 4 post buss bar and ran the three load negs to the buss bar and then ran a cable from the 4th buss bar post to the Load side of the shunt. To complete the circuit and install I ran one very thick cable from the power side of the shunt to the last battery in my parallel battery bank.

Here's a photo of my buss bar and my shunt:

[Out N About]

Well, I mis-read the Winnie wiring sheet. The previous owner had downsized from three to two 12v batteries, and the cables are not where they were when new. Winnebago shows the house cables on battery A positive and battery C negative, while the charger is connected to battery C positive and battery A negative, basically a crisscross of both sets. This would force current equally through all three batteries and allow the batteries to help filter out charger noise. I'm going to duplicate that configuration, except I'll have to run my charger's negative through the shunt as soon as I get another short cable. Thanks to all.

[creativepart]

That sounds like it used to be 6v batteries wired in series and doing that with 12v batteries will kill the batteries.

12v batteries are wired in Parallel and 6v batteries are wired in Series.

In Series the positive of one battery is connected to the negative of the next battery. You do this in pairs to create one 12v battery out of 2-6v batteries. And then the now 12v pairs are connected in Parallel.

That is if I'm understanding you correctly.

With 12v batteries the positives should all be connected to the positive post and the negative wires should all be connected to the negative posts.

Like this: