Jump to content

Victron Easysolar 5kVA & ReVOV batteries


HennieJH

Recommended Posts

I have lately been experiencing a strange scenario, my ReVOV batteries previously discharged below 50% (Limited by Inverter), they discharged at times down to 20% and once to 10%. On 31 Dec 2019, one morning, the battery was at 39% and all of a sudden power went off, switched over to Eskom power and the inverter sounded and showed a low battery warning. System was reset to fix issue. Now this morning, same scenario happens again, 20 days apart. What could be the cause? 39% was never before an issue, why now?

Link to comment
Share on other sites

4 hours ago, HennieJH said:

What could be the cause? 39% was never before an issue, why now?

Hi Hennie,, please look at the voltage at that stage. I suspect the system switches off because of low voltage and not the SOC. Also look at the output load at that exact moment, maybe you switched on a kettle or something like that that caused the voltage to sag below the low cutoff setting. 

Link to comment
Share on other sites

53 minutes ago, HennieJH said:

Will check when it happens again, Thanks 

Hennie, you have a colour control in the easy solar. It has all the info available. You can scroll back and see what happened just before the unit switched off. If you are not comfortable with retrieving the info, please send me a PM and I will assist from there. 

Link to comment
Share on other sites

On 2020/01/19 at 6:46 AM, HennieJH said:

39% and all of a sudden power went off

As Jaco said, we really should inspect the data logged to VRM. What I would guess, is that the BMS switched off the DC to protect the battery, but it's not always easy to see this, because for many battery makers the BMS itself loses power when the protection mechanism activates (so it can't even tell us that it did it). This remains the best guess however, because if it was something else (like a low voltage condition causing the Multi to go into sustain mode) you would not have lost power.

So working with this guess, why would the BMS freak out at 39%? Well, we had one similar case here with a different battery where the BMS was configured for the incorrect capacity. When the battery was at 50% it was really much closer to completely empty. When you tried to discharge the battery below this point it would abruptly drop off to 0% SOC, and on recharge it would make a large jump to 100%.

The second possibility -- this is the bad one -- is that one of the cells has less capacity than the others. When it got to 39%, that BMS noticed that the voltage on one of the cells was dangerously low and activated its protection. If this is the case, your supplier might have to swap it out. What would be useful here is if you could somehow find the software to talk to your particular BMS to see if there is a low cell.

(That's also the reason for the BMS extensions in Venus 2.40, once the battery makers implement them, you'd be able to see where the lowest cell is and what its voltage is).

Link to comment
Share on other sites

33 minutes ago, plonkster said:

As Jaco said, we really should inspect the data logged to VRM. What I would guess, is that the BMS switched off the DC to protect the battery, but it's not always easy to see this, because for many battery makers the BMS itself loses power when the protection mechanism activates (so it can't even tell us that it did it). This remains the best guess however, because if it was something else (like a low voltage condition causing the Multi to go into sustain mode) you would not have lost power.

So working with this guess, why would the BMS freak out at 39%? Well, we had one similar case here with a different battery where the BMS was configured for the incorrect capacity. When the battery was at 50% it was really much closer to completely empty. When you tried to discharge the battery below this point it would abruptly drop off to 0% SOC, and on recharge it would make a large jump to 100%.

The second possibility -- this is the bad one -- is that one of the cells has less capacity than the others. When it got to 39%, that BMS noticed that the voltage on one of the cells was dangerously low and activated its protection. If this is the case, your supplier might have to swap it out. What would be useful here is if you could somehow find the software to talk to your particular BMS to see if there is a low cell.

(That's also the reason for the BMS extensions in Venus 2.40, once the battery makers implement them, you'd be able to see where the lowest cell is and what its voltage is).

Thanks for the feedback. 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...