# My bmv 700 amp is showing -20 amps when solar app shows +30 amps **URL:** \ **Category:** Q&A and troubleshooting\ **Tags:** bmv, marine, diy\ **Created:** [18 December 2024 01:51 UTC](https://community.victronenergy.com/t/my-bmv-700-amp-is-showing-20-amps-when-solar-app-shows-30-amps/15755 "2024-12-18T01:51:40Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![steveswift](https://avatars.discourse-cdn.com/v4/letter/s/ea5d25/32.png) [@steveswift](https://community.victronenergy.com/u/steveswift)\ **Post date:** [18 December 2024 01:51 UTC](https://community.victronenergy.com/t/my-bmv-700-amp-is-showing-20-amps-when-solar-app-shows-30-amps/15755/1 "2024-12-18T01:51:40Z")
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. ---
**Author:** ![steveswift](https://avatars.discourse-cdn.com/v4/letter/s/ea5d25/32.png) [@steveswift](https://community.victronenergy.com/u/steveswift)\ **Post date:** [18 December 2024 23:24 UTC](https://community.victronenergy.com/t/my-bmv-700-amp-is-showing-20-amps-when-solar-app-shows-30-amps/15755/3 "2024-12-18T23:24:32Z")
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: ![image](https://europe1.discourse-cdn.com/victron/original/2X/f/f84f0c856ce821045db1d7786a01db4cb57cdbff.png) 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 ---
**Author:** ![steveswift](https://avatars.discourse-cdn.com/v4/letter/s/ea5d25/32.png) [@steveswift](https://community.victronenergy.com/u/steveswift)\ **Post date:** [19 December 2024 01:47 UTC](https://community.victronenergy.com/t/my-bmv-700-amp-is-showing-20-amps-when-solar-app-shows-30-amps/15755/5 "2024-12-19T01:47:10Z")
No. There is only one wire connected to the battery minus going to the shunt. See picture attached: ![](https://europe1.discourse-cdn.com/victron/original/2X/d/dc9e484c81685317a9f67226ea234cdc0fda9f69.jpeg) Unless the shunt is positioned upside down and thus the leads reversed? ---
**Author:** ![ChrisA](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/chrisa/32/3154_2.png) [@ChrisA](https://community.victronenergy.com/u/ChrisA)\ **Post date:** [19 December 2024 01:47 UTC](https://community.victronenergy.com/t/my-bmv-700-amp-is-showing-20-amps-when-solar-app-shows-30-amps/15755/6 "2024-12-19T01:47:54Z")
> [@Ludo](#): > > ng 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. ---
**Author:** ![steveswift](https://avatars.discourse-cdn.com/v4/letter/s/ea5d25/32.png) [@steveswift](https://community.victronenergy.com/u/steveswift)\ **Post date:** [19 December 2024 03:14 UTC](https://community.victronenergy.com/t/my-bmv-700-amp-is-showing-20-amps-when-solar-app-shows-30-amps/15755/8 "2024-12-19T03:14:33Z")
I have 5 x 100 amp/hr lifepo4 batteries hence 500ah. What is 50 MV? ---
**Author:** ![steveswift](https://avatars.discourse-cdn.com/v4/letter/s/ea5d25/32.png) [@steveswift](https://community.victronenergy.com/u/steveswift)\ **Post date:** [19 December 2024 03:17 UTC](https://community.victronenergy.com/t/my-bmv-700-amp-is-showing-20-amps-when-solar-app-shows-30-amps/15755/9 "2024-12-19T03:17:09Z")
Btw have done a quick check of lead between shunt and bmv plus checked connections. All seemed good. ---
**Author:** ![steveswift](https://avatars.discourse-cdn.com/v4/letter/s/ea5d25/32.png) [@steveswift](https://community.victronenergy.com/u/steveswift)\ **Post date:** [19 December 2024 03:26 UTC](https://community.victronenergy.com/t/my-bmv-700-amp-is-showing-20-amps-when-solar-app-shows-30-amps/15755/10 "2024-12-19T03:26:26Z")
I’ve not got a smart shunt. How do I adjust shunt? ---
**Author:** ![steveswift](https://avatars.discourse-cdn.com/v4/letter/s/ea5d25/32.png) [@steveswift](https://community.victronenergy.com/u/steveswift)\ **Post date:** [20 December 2024 00:57 UTC](https://community.victronenergy.com/t/my-bmv-700-amp-is-showing-20-amps-when-solar-app-shows-30-amps/15755/12 "2024-12-20T00:57:01Z")
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.