question

Enrico Marzico avatar image
Enrico Marzico asked

Smart Shunt not changing battery percentage from MPPT charging

Hi Everyone, few details:

- Boat with 4x74ah 12v lead acid battery bank

- I have a fixed -0,8Ah discharge due to security system, connectivity..etc...

- Smart shunt 500a

- victron multiplus 12/2000

- victron mppt 75/15 + 100w solar panels

ACTUALLY the negative terminal from mppt in connected directly to the batteries and NOT to the load side of the shunt, so the shunt is not reading the incoming current from the mppt, i will change this BUT:

The mppt is correctly feeding 14,7v into the batteries (absorption) and the shunt reads the value but also with several hours of solar feed the battery percentage keep going down. The feeded current is way more than the -0,8ah consumption so i cannot explain this.

The problem is the battery percentage beacuse the tension is ok, the Smart shunt doesn't update the battery percentage.


Any advice? Also any advice of setting not to kill my batteries with charging cycles? I just want my solar to cover this -0,8ah consumption and keep batteries charged and ready when i'm not into the boat.



screenshot-2023-04-03-alle-130526.pngscreenshot-2023-04-03-alle-130553.pngscreenshot-2023-04-03-alle-133502.pngscreenshot-2023-04-03-alle-112734.png


MPPT Controllersbattery chargingSmartShunt
screenshot-2023-04-03-alle-112734.png (136.4 KiB)
screenshot-2023-04-03-alle-130526.png (174.5 KiB)
screenshot-2023-04-03-alle-130553.png (101.0 KiB)
screenshot-2023-04-03-alle-133502.png (146.5 KiB)
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

2 Answers
wkirby avatar image
wkirby answered ·

ACTUALLY the negative terminal from mppt in connected directly to the batteries and NOT to the load side of the shunt, so the shunt is not reading the incoming current from the mppt, i will change this BUT:

This is the reason. If the shunt is not registering charge current that how can it know how much current is going to the battery? When you change the MPPT to the load side of the shunt then it will have a chance to see the MPPT current.

2 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Enrico Marzico avatar image Enrico Marzico commented ·
Ok but, the smart shunt is not detecting that the voltage is changed? And why the soc is not automatic set to 100% as the voltage is above the 14,6v for more than 3 minutes and the tail current is below the 4%?
0 Likes 0 ·
derrick thomas avatar image derrick thomas Enrico Marzico commented ·
Until you connect the MPPT to the load side of the shunt, it sees nothing. No current, and no tail current either.
0 Likes 0 ·
giampaolo avatar image
giampaolo answered ·

Per avere una corretta lettura da parte dello smart shunt dovresti seguire uno schema tipo quello allegato evitando di bypassarlo con carichi ed alimentazioneimmagine.png


immagine.png (38.7 KiB)
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.