My bmv 700 is showing -20 amps when the smart solar app is showing +30 amps. This is a recent development. I have repositioned the lead to the battery monitor from the battery to the shunt system terminal and there was no change in the reading.
Please post a simple drawing of your installation and the settings of bmv and mppt.
I am not able to give you a simple drawing of the installation. I didn’t install it. It was not done correctly at the time, in that the settings on my ac charger weren’t changed properly but I’ve put in the correct numbers. I also tweaked the bmv settings on that unit(non-blue tooth) and also my smart solar app. This was about 5/6 months ago. Since then I’ve not (or rarely- twice!) seen the bmv return to 100% capacity when it reaches its zenith. The smart solar app will show battery voltage at 14.45, it will go to absorption, still putting in full amps (50+), for a while (20+ minutes). However the bmv doesn’t reset to 100%, it would show 70% full. The next day it would be lower still to eventually it would be 0% capacity and 0 hours of charge. I’d then (if not before) reset the synchronisation to 100% when it was at 14.45 volts.
There has always been a discrepancy between the app and the bmv battery voltage and the amp input from the solar panels. Recently this has jumped to huge discrepancy in the amp input.
I think it may be a faulty bmv. As I didn’t change anything before the discrepancy became apparent, it seemed to just happen by itself.
The settings for the 150/85 TR are as follows:
My bmv settings are as follows:
Battery cap 500ah
Charged voltage 14.1
Tailed current 2.0%
Charged detection time. 3 min
Peukert 1.05
Charge effiency 99%
Current threshold 0.10 amp
Time to go averaging period 03
No, the minus of the solar chargers is probably connected on the wrong side of the shunt.
It’s probably the most common error made in these installations.
Easy to see, there should only be one wire connected to battery minus going to the shunt.
No. There is only one wire connected to the battery minus going to the shunt.
See picture attached:
Unless the shunt is positioned upside down and thus the leads reversed?
a few options:
- All Loads and charging sources on the load side of the Shunt as described above.
- Calibration of the shunt is off, remove all loads and chargers, and re-calibrate (zero)
- the readings are correct, remember that the shunt is a NET value, (charge - load = net) so potentially there is 50A of load, 30A from the solar, and another 20A from the battery.
- the BMV cable between the Shunt and the Display is damaged. I have seen this cause issues like this.
as for your shunt not reaching 100%, the 3 settings that wil laffect this are your Tail current (default is 4%), the charged voltage (for LiFePO4 suggest 14V is plenty) and the charge detection time for those two factors to be true, then it will show 100%.
also seeing your settings for the 150/85, I can suggest that you use the Smart Lithium pre-set, and if needed, adjust the Absorbtion and Float voltages from there. You still have adaptive Absorbtion for example, which should usually be fixed for LiFePO4.
hope that helps.
Sorry if I’m boring, but what is connected to the minus of the second battery ?
Your shunt is connected right, the left connection is for the battery, so if there is nothing else connected the shunt itself must be the cause…
The settings are 500A / 50mv ??
I have 5 x 100 amp/hr lifepo4 batteries hence 500ah. What is 50 MV?
Btw have done a quick check of lead between shunt and bmv plus checked connections. All seemed good.
I’ve not got a smart shunt. How do I adjust shunt?
Your bmv700 is the grandfather of the smartshunt
Use victronconnect, go to settings, the second tab from the bottom will give you the shunt data.
Should be 500A, 50mv.
The zero adjust can be done in the battery section.
Have you checked the minuses of all batteries for extra wiring ? Maybe a lazy electrician found a shorter way to ground ?
My bmv 700 doesn’t have a smart shunt. So I disconnected the negative load side of shunt and recalibrated zero on the unit (#9) and it seems to be fine now. I missed the synchronisation for 100% but will do that at a later date. I think all my problems came from a wire being wrongly joined to battery and not load side of shunt. Fingers crossed.
Thank you for all your help.
If all parameters are set correct it will synchronize all by itself on the next full charge