Practical Use of a Battery Monitor

autostaretx

Erratic Member
Wonderful... the empirical determination of battery capacity alone was worth the price of admission...

How quaint that NAPA doesn't provide the fundamental parameter of capacity (ampere hours).

thanks
--dick
 

daveflack

New member
I have used the Victron in another RV for 4 years and couldn't live without it. Just bought a Navion 08J and will install. Where did you place the monitor and how did you route the wiring?
 

TJLee089

2013 Itasca Reyo 25R
Routing the signal cable between the shunt and the monitor is the only difficult and challenging part of the installation. I mounted the monitor with my other gauges. I drilled a 2 inch hole and had to enlarge it slightly. I didn't use the included bezel. See attached photos.

To run the signal cable, I removed as many of the panels and drawers as possible along the cable path. I dropped a string with a weight from near the monitor location and used it as a cable puller. I drilled one hole through the floor of the van, which was concealed by a removable cabinet floor. I used flexible plastic conduit between this hole and the battery compartment and sealed the floor hole.

Spend the time to plan your route carefully. I spent the better part of a day on this and am pleased with the result.

I still think the Victron is the best choice because the signal cable is included and is modular. The only thing you will need to provide is the short battery cable between the battery and the shunt. Be sure to use a cable size that is no smaller than your existing negative battery cable. It is unlikely you will find what you need off-the-shelf at an auto store. Have a repair shop make it for you.

Thanks for your interest and GOOD LUCK!
 

Attachments

NBB

Active member
The cable on the left of the shunt looks pretty small - inadequate - compared to the other cables being used around the battery. The current traveling through all of them is the same, they should all be the same gauge.
 

autostaretx

Erratic Member
OK, i give up... What's that thing? (white arrow)
It looks like another shunt inserted in the positive cable run?
(i suppose it could be a fuse...)

WhatsThat.jpg

--dick
 

icarus

New member
The cable on the left of the shunt looks pretty small - inadequate - compared to the other cables being used around the battery. The current traveling through all of them is the same, they should all be the same gauge.
Not quite.

The signal cable from the shunt will carry ~1/100 or less of the shunt current, hence the reason to use a shunt in the first place.

Dick,

I'm guessing it is a fuse.

Icarus
 

TJLee089

2013 Itasca Reyo 25R
"The cable on the left of the shunt looks pretty small - inadequate - compared to the other cables being used around the battery. The current traveling through all of them is the same, they should all be the same gauge."

The cable you are referring to (left side of shunt) is the OEM 1 gauge cable, as are all other OEM cables. If it is too small, you know more than the motorhome design engineers. The cable I added (right side of shunt) is 2/0 gauge, two sizes larger. That's what my neighbor/mechanic had available.

Never judge a book by its cover.
 
Last edited:

Oldfartt

Member
To help equalize the current through the two batteries, the new negative cable should be connected to the left battery, not the right hand battery.
The device in question is undoubtedly a Fuse. It is there to protect the wiring and is in the right place, close to the battery terminals.
Cheers

Ross
 
Last edited:

NBB

Active member
Must be the photos. MB uses 1 ga to the aux battery, the cable I questioned looks like a 2 or 4 gage.

For something like a 1500-2000 watt inverter more than a just a couple feet away, 1 gage would probably be too small, most guys here are using 2/0 or thicker. Lots of threads here, lots of info in the various inverter's instruction manuals.

That's definitely a fuse, very much like the one MB should be shipping with their aux fuse holder instead of a piece of solid copper...
 

TJLee089

2013 Itasca Reyo 25R
To help equalize the current through the two batteries, the new negative cable should be connected to the left battery, not the right hand battery.
The device in question is undoubtedly a Fuse. It is there to protect the wiring and is in the right place, close to the battery terminals.
Cheers

Ross
I understand your point, however I wired the new cable to the EXACT same battery location as the original negative cable. You will notice two positive cables coming from the bank. The yellow (end of cable) is noted as "coach battery." The orange (end of cable) is noted as "inverter." This is the way Winnebago built it.

See http://www.winnebagoind.com/diagram/2013/13_wire_182140.pdf

I believe this indicates that under "normal" usage, i.e. not using the inverter, the wiring is correct - positive from one battery, negative from the other.

When the inverter is used, both positive and negative would be from the battery on the right. This appears less than ideal per your comment.

I plan on replacing the inverter with an inverter/charger that will provide 3 stage charging, essentially overpowering the charging from the converter, which is essentially a float charge.

My question is this:
Should I relocate the "orange" cable from the right battery positive to the left battery positive to equalize the current flow?

Thanks for your comment.
 

TJLee089

2013 Itasca Reyo 25R
Must be the photos. MB uses 1 ga to the aux battery, the cable I questioned looks like a 2 or 4 gage.

For something like a 1500-2000 watt inverter more than a just a couple feet away, 1 gage would probably be too small, most guys here are using 2/0 or thicker. Lots of threads here, lots of info in the various inverter's instruction manuals.

That's definitely a fuse, very much like the one MB should be shipping with their aux fuse holder instead of a piece of solid copper...
Inverter is 1000 watt. All wiring is OEM except for the 2/0 I added. This was built by Winnebago, not MB.

Thanks.
 

Oldfartt

Member
TJ,

Yes, you can move the orange term wire to the left battery as this is the easiest to do! It will satisfy the current sharing a little better.
As the winnebago diag shows, the fuse is in the feed to the inverter and is rated at 150Amp.
Your neighbor/electrician has rated the new cable OK, the bigger the better! good to see crimped and insulated sleeves on the lugs.
For safety reasons I suggest temporarily removing the earth cable on the current current shunt before relocating the the orange wire.

Cheers

Ross
 

TJLee089

2013 Itasca Reyo 25R
TJ,

Yes, you can move the orange term wire to the left battery as this is the easiest to do! It will satisfy the current sharing a little better.
As the winnebago diag shows, the fuse is in the feed to the inverter and is rated at 150Amp.
Your neighbor/electrician has rated the new cable OK, the bigger the better! good to see crimped and insulated sleeves on the lugs.
For safety reasons I suggest temporarily removing the earth cable on the current current shunt before relocating the the orange wire.

Cheers

Ross
Makes sense. Thanks.
 

twrooney

Member
Thanks for all the information. Since I have these same batteries in my Winnebago view I am using your calcs for the amp hour capacity for setting up my Trimetric monitor.
 

TJLee089

2013 Itasca Reyo 25R
Glad to be of help. I suppose the reason that battery monitor manufacturers don't provide similar information is:

1. Most folks installing battery monitors have quality batteries for which the AH capacity is provided and no calculations are needed (I would not put the NAPA 8240 batteries in this category).
2. The math would be too intimidating for most and might dissuade them from considering a battery monitor.

In any case, I agree with many others that a good battery monitor is a vital add-on.
 

Top Bottom