Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Display Modes
Old 07-06-2019, 02:18 PM   #1
Retired Panpsychist
 
Theo's Avatar
 
Join Date: Jul 2016
Location: Western Massachusetts
Posts: 1,041
Victron BMV-712 Inaccuracy - Need 1A Fuse

Today I investigated what I believe to be a slight difference in the metered voltage of my GC2 battery bank and what the BMV-712 battery monitor reports. Granted, it is only a couple of mV, but (being somewhat OCD) the difference between the BMV-712 and the Fluke were puzzling.

Before I did anything radical, I searched the intertubes for "BMV-712 Accuracy" and received some interesting hits. The first was a BMV-712 Accuracy Article posted to the Victron Energy Community Forum documenting the discrepancy. Interestingly, the author solved the problem by replacing his unit's 100mA fuse with a 1A fuse to reduce the resistance.

Then, I came across a response by a Victron staff member (mvader) to a similar accuracy post indicating that a whole batch of 712's were sent out with an incorrect (100mA) inline fuse for the shunt's power. In his/her comments, the suggested fix is to replace the incorrect fuse with a 1A one.

Well, I checked the fuse for my 712 and it was indeed a 100mA fuse which was quickly replaced by a 1A. So now I have disconnected all power in the RV and am waiting for things to settle to see if this has solved this (admittedly OCD) issue.

Perhaps those with the BMV-712 battery monitor should check your inline shunt's power fuse. Or not.
__________________
Theo & Carol

2007 GoldenDoodle ("Cooper") R.I.P.
2020 Rockwood Roo 23IKSS
2015 F-150 4WD XLT SCab, 5.0L, 3.73, 36gal, HD Towing Pkg (53A), 1,980lb Payload
Theo is offline   Reply With Quote
Old 07-06-2019, 10:30 PM   #2
Senior Member
 
Join Date: Aug 2016
Posts: 1,834
Any idea if it applies to the older 701s?
aeblank is offline   Reply With Quote
Old 07-06-2019, 11:42 PM   #3
Senior Member
 
Join Date: Jul 2017
Location: California
Posts: 7,616
Since I rarely use the display of my 712(bluetooth only) I doubt I would notice much difference. I am going to check the fuse though.
babock is offline   Reply With Quote
Old 07-06-2019, 11:53 PM   #4
Senior Member
 
Join Date: Jan 2013
Location: Space Coast of Florida
Posts: 3,954
Thx for the info. I use the Bluetooth also but did notice the voltage reading was lower than my connected dvm. I will check the fuse.

It seems the SOC is correct though based on accumulated amps drawn.
__________________


2016 Siverback 33IK, Towed 50K+ mile
2018 Ford F-350 Lariat 6.7L V8 Diesel 4WD Crew Cab

"If you don't know where you are going, any road will get you there."
dalford is offline   Reply With Quote
Old 07-07-2019, 08:07 AM   #5
Retired Panpsychist
 
Theo's Avatar
 
Join Date: Jul 2016
Location: Western Massachusetts
Posts: 1,041
Update:

Checked the 712 with the Fluke this morning and the situation is corrected! Looks like the 1A fuse did the trick. One less mystery in life.

Also, I should note that my fuse was removed for about 5 to 7-minutes and the 712 retained all its previous settings. However, I had taken the precaution of saving all the settings to a file and archiving them (via that facility in the Victron app).

aeblank - I'm not sure if the 701 may have shipped with the wrong fuse. There may be some more info in the Victron Community Forum or you can just check it. If you aren't getting difference between the Victron and your DVM reading (usually in the hundredths of a volt), then I'd think you're all set.

babock - I, too, rely on my phone to read the info. However, the data sent by BT is, of course, dependent on the BMV-712 signal processing. My sense is to make sure all the incoming data to the 712 is as accurate as possible to allow its algorithms to work properly. Since I can't see the 712's code, I'm not sure what the "downstream" effect produced by slightly inaccurate signals will be. But then, there's my OCD .

dalford - I think for the most part the SOC was fairly accurate, though it seemed that my (temperature-compensated) voltages strayed a bit from what I might expect from tables to which I have been referring. Not much, but some.
__________________
Theo & Carol

2007 GoldenDoodle ("Cooper") R.I.P.
2020 Rockwood Roo 23IKSS
2015 F-150 4WD XLT SCab, 5.0L, 3.73, 36gal, HD Towing Pkg (53A), 1,980lb Payload
Theo is offline   Reply With Quote
Reply

Tags
fuse

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Forest River, Inc. or any of its affiliates. This is an independent, unofficial site.



All times are GMT -5. The time now is 05:34 AM.