New Victron MPPT Firmware

[noelex 77]

Originally Posted by Davo1404

Still waiting for an update to fix the slow amperage refresh.

The latest software that was released on May 23 was reportedly to fix the update rate of the battery current reading.

I presume you have uploaded this and it has not fixed the problem. Is that correct?

[Davo1404]

Originally Posted by noelex 77

The latest software that was released on May 23 was reportedly to fix the update rate of the battery current reading.

I presume you have uploaded this and it has not fixed the problem. Is that correct?

No this update hasn't shown up yet.

[noelex 77]

Originally Posted by Davo1404

No this update hasn't shown up yet.

The updates do tend to be released at different times for different platforms.

I don’t know if it will fix the issue, as I was not having any problems before this update, but I would expect so. However, the fix involves removing the improved resolution.

[JmanC]

So is there a way to send the real end amps info that are flowing into battery to the mppt using the BMV712? Or some other way? Like a add on wireless shunt?

[cofc]

I’ll try reviving this old thread regarding the rebulk voltage offset for Victron MPPTs.

I have 3 100/20 MPPTs charging my 12v house bank. They usually have the batteries fully charged around noon and then go to float mode. I have my rebulk voltage set to 12.9v. After a couple of hours of float voltage, the bank has usually dropped below the rebulk voltage of 12.9v, however the chargers do not switch back to the bulk setting. I can force them to do so by switching them on and off, or turning on a large load dropping the battery voltage well below the rebulk setting of 12.9v.

I’ve tried the Victron forums with no luck, and Google turns up dead ends. I read this whole thread and have turned off the tail current option (although I don’t know that that affects the rebulk setting). Any thoughts? Does everyone else’s systems start a new bulk charge after 1 minute below the rebulk voltage?

[FlyingScot]

Originally Posted by cofc

...After a couple of hours of float voltage, the bank has usually dropped below the rebulk voltage of 12.9v...

If you're losing amp hours in float mode, I would up the float voltage just enough to keep the amps slightly positive (into the batteries).

[cofc]

Originally Posted by FlyingScot

If you're losing amp hours in float mode, I would up the float voltage just enough to keep the amps slightly positive (into the batteries).

I think the problem with that would be that none of the loss are static. I have refrigerators turning on and off, kids charging laptops, etc. if I increase float to cover that, when the loads are actually off, the float will be too high.

It seems there’s functionality in the chargers to fix this issue, but for some reason it doesn’t work on my system.

[noelex 77]

Originally Posted by cofc

I’ll try reviving this old thread regarding the rebulk voltage offset for Victron MPPTs.

I have 3 100/20 MPPTs charging my 12v house bank. They usually have the batteries fully charged around noon and then go to float mode. I have my rebulk voltage set to 12.9v. After a couple of hours of float voltage, the bank has usually dropped below the rebulk voltage of 12.9v, however the chargers do not switch back to the bulk setting. I can force them to do so by switching them on and off, or turning on a large load dropping the battery voltage well below the rebulk setting of 12.9v.

I’ve tried the Victron forums with no luck, and Google turns up dead ends. I read this whole thread and have turned off the tail current option (although I don’t know that that affects the rebulk setting). Any thoughts? Does everyone else’s systems start a new bulk charge after 1 minute below the rebulk volt

You can force a re-bulk/absorption cycle by using the "equalisation" cycle. If you want to use this feature, set the equalisation voltage to be the same as the absorption voltage rather than the much higher voltage that would normally be used for equalisation.

Then if you want to force the controller to initiate another absorption period, the "equalisation" mode can be selected via the app. The extra absorption time can be set for a few minutes or a few hours depending on what is needed, and can be canceled with a push of a button on the app.

[cofc]

Originally Posted by noelex 77

You can force a re-bulk/absorption cycle by using the "equalisation" cycle. If you want to use this feature, set the equalisation voltage to be the same as the absorption voltage rather than the much higher voltage that would normally be used for equalisation.

Then if you want to force the controller to initiate another absorption period, the "equalisation" mode can be selected via the app. The extra absorption time can be set for a few minutes or a few hours depending on what is needed, and can be canceled with a push of a button on the app.

Yeah, I saw that you recommended that earlier in the thread. I appreciate it, but it’s a bummer that we’re still having to work around a problem that Victron “solved” but didn’t solve. Unless I’m doing something wrong. Do your controllers rebulk at whatever setting you specify?

[rslifkin]

Originally Posted by cofc

Yeah, I saw that you recommended that earlier in the thread. I appreciate it, but it’s a bummer that we’re still having to work around a problem that Victron “solved” but didn’t solve. Unless I’m doing something wrong. Do your controllers rebulk at whatever setting you specify?

My 100/30 MPPTs rebulk after 1 minute at the set rebulk voltage, just like the book says they should. Once in float, the only time I'll get a rebulk is if I draw enough power to exceed the max available solar output and then pull the voltage down to the rebulk limit. Otherwise the MPPTs just turn up the amps and stay in float (maintaining float voltage).


Keep in mind when you're doing settings, the rebulk voltage is set as an offset from float voltage, not an absolute voltage. So if you set it to 1V, it'll rebulk 1 volt below float voltage.

[noelex 77]

Originally Posted by cofc

Yeah, I saw that you recommended that earlier in the thread. I appreciate it, but it’s a bummer that we’re still having to work around a problem that Victron “solved” but didn’t solve. Unless I’m doing something wrong. Do your controllers rebulk at whatever setting you specify?

They re-bulk without any problem in my system, but the Victron algorithm does not initiate any extra absorption time.

So if you have high drain on the system (for example some electric cooking) if this is done after the normal absorption time is finished, the controller will initiate a new bulk cycle in response to the reduced battery voltage from the high load (re-bulk voltage reached), but once the absorption voltage is reached the system will drop back to float without initiating any new absorption time.

The above will replace some of the energy used on the high load, but typically not all. The controller will be in float when the batteries are less than 100% full. This is where manually initiating a new absorption cycle using the trick of selecting "equalisation" (which is set to absorption voltage) is most worthwhile.

Of course a perfect charging algorithm would do this without manual intervention, but these charging algorithms are never perfect. Tweaking the process manually, as I tend to do, probably only has slight practical benefit on battery life so if you prefer a set and forget system that is also fine.

[cofc]

Originally Posted by rslifkin

My 100/30 MPPTs rebulk after 1 minute at the set rebulk voltage, just like the book says they should. Once in float, the only time I'll get a rebulk is if I draw enough power to exceed the max available solar output and then pull the voltage down to the rebulk limit. Otherwise the MPPTs just turn up the amps and stay in float (maintaining float voltage).


Keep in mind when you're doing settings, the rebulk voltage is set as an offset from float voltage, not an absolute voltage. So if you set it to 1V, it'll rebulk 1 volt below float voltage.

Hmm, I must be doing something wrong. I have float voltage set to 13.02v (per US Battery specs) and my rebulk offset to 0.12v. So theoretically once the battery voltage drops below 12.9v for one minute it should initiate a new bulk cycle, correct? However it’s not. I’ve come back to the boat at 2:00pm, in full sun, with the batteries at 12.7v and the charge controllers in float.

I do have my starting battery connected to the BMV-712, which is networked with the charge controllers. But surely they’re not taking the starting battery voltage into account when deciding when to rebulk, right? It’s on a relay so it always stays at 13v.

[rslifkin]

Originally Posted by noelex 77

They re-bulk without any problem in my system, but the Victron algorithm does not initiate any extra absorption time.

So if you have high drain on the system (for example some electric cooking) if this is done after the normal absorption time is finished, the controller will initiate a new bulk cycle in response to the reduced battery voltage from the high load (re-bulk voltage reached), but once the absorption voltage is reached the system will drop back to float without initiating any new absorption time.

The above will replace some of the energy used on the high load, but typically not all. The controller will be in float when the batteries are less than 100% full. This is where manually initiating a new absorption cycle using the trick of selecting "equalisation" (which is set to absorption voltage) is most worthwhile.

Of course a perfect charging algorithm would do this without manual intervention, but these charging algorithms are never perfect. Tweaking the process manually, as I tend to do, probably only has slight practical benefit on battery life so if you prefer a set and forget system that is also fine.

With mine set to a fixed absorption time and ending based on tail current they do go through a full absorb cycle to target tail current on a rebulk.

[noelex 77]

Originally Posted by cofc

Hmm, I must be doing something wrong. I have float voltage set to 13.02v (per US Battery specs) and my rebulk offset to 0.12v. So theoretically once the battery voltage drops below 12.9v for one minute it should initiate a new bulk cycle, correct? However it’s not. I’ve come back to the boat at 2:00pm, in full sun, with the batteries at 12.7v and the charge controllers in float.

I do have my starting battery connected to the BMV-712, which is networked with the charge controllers. But surely they’re not taking the starting battery voltage into account when deciding when to rebulk, right? It’s on a relay so it always stays at 13v.

The normal behaviour is to initiate the bulk phase and then drop back to float if the absorption time has expired. So it is not surprising it was sitting at float, but in full sun that should be at the 13.02v you have set rather than 12.7. It should not be using the starting battery voltage, but a don't have a Victron battery monitor so I cannot offer any suggestions on what might be wrong, but I am sure someone else can help.

With the BMV-712 you should have the option to terminate the absorption phase using battery return amps. This is the most accurate way to ensure the absorption time is correct on every cycle, so this option is worth selecting.

[noelex 77]

Originally Posted by rslifkin

With mine set to a fixed absorption time and ending based on tail current they do go through a full absorb cycle to target tail current on a rebulk.

This makes sense. The re-bulk voltage will initiate a new absorption cycle if the absorption time has not previously expired.

Unfortunately, tail current will not terminate the absorption cycle accurately. For example: if there is a load greater than the tail current setting, the absorption phase will never be terminated.