question

4711austria avatar image
4711austria asked

Balancing via MPPT RS450 ?

Hi

just reading the operational manual, would it be possibel inside a 3xMP2 5k ESS System with BMS on 54,4V (Pace BMS Pack Volatge) to run a higher voltage as 55,2V to start the active Helllltec Balancer (3,45V) ?

Just to automize the balancing process every week...

Did anybody use that for his LifePO4 packs?


rs450
2 |3000

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

2 Answers
nickdb avatar image
nickdb answered ·

If its a managed battery DVCC is likely forced on and the BMS will set the limits for all chargers.

11 comments
2 |3000

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

4711austria avatar image 4711austria commented ·
that means the MPPT cannot raise the voltage to balancing?
0 Likes 0 ·
nickdb avatar image nickdb ♦♦ 4711austria commented ·
The BMS will send its CVL to the system (if it is connected and recognised) at which point every charger will ignore its own settings and run at the BMS requested voltage.

If you disconnect the battery BMS and disable DVCC, then you can set voltages manually.

Balancers are not normally used with lithium batteries. The BMS is unlikely to enjoy a higher voltage, Pace already likes to send high voltage alarms.

Balancers are only seen sometimes if someone tries to connect batteries in series. Where vendors support this, their BMS is usually capable of dealing with this layout and don't need external help.

Why are you trying to do this?

0 Likes 0 ·
Fideri avatar image Fideri 4711austria commented ·
@4711Austria

@nickdb has explained it nicely. With your approach, what happens when the BMS decides no charge to the battery? If you must do it, you have to disable the BMS or change its parameters. Neither is recommended.

F

0 Likes 0 ·
4711austria avatar image 4711austria Fideri commented ·

that means it is not possible to use this function

of course LifePO4 needs Balancer, not all time and not during daily use, just to take care of the capacity differences in cells.

therefore I wanted to use it, but so I need to do it via DVCC again.

0 Likes 0 ·
nickdb avatar image nickdb ♦♦ 4711austria commented ·
If you have a pace bms it balances. That is the purpose of the BMS.
0 Likes 0 ·
4711austria avatar image 4711austria nickdb ♦♦ commented ·
forget about the passiv Balancer on the Pace BMS and it is not the purpose to balance.

as I wrote the Gobel has the Helltec 4A active installed.

0 Likes 0 ·
Alexandra avatar image Alexandra ♦ 4711austria commented ·
The pace bms will cut off charge long before the heltec is triggered to do its job.


The pace simply wont allow the higher charge voltage.

Unless you can program the bms to allow the higher charge or the heltec to start balancing much sooner, there is no way the two can work together.

0 Likes 0 ·
4711austria avatar image 4711austria Alexandra ♦ commented ·
No.

Pls refer to the web and common YT Videos.

0 Likes 0 ·
Fideri avatar image Fideri 4711austria commented ·
Even DVCC won't do it. It will only take your figures if they are lower than what the BMS is asking for. This is not what you want to achieve.

F.

0 Likes 0 ·
4711austria avatar image 4711austria Fideri commented ·
No.

Pls refer to Web, Specs and YT Videos.

0 Likes 0 ·
Alexandra avatar image Alexandra ♦ 4711austria commented ·
What web, what specs and what you tube video?

You have incompatibility issues.

Change the design and components choice.

0 Likes 0 ·
Alex Pescaru avatar image
Alex Pescaru answered ·

Hi @4711Austria

I see that you are pretty determined to do it your way... :-))

In that light, even if there are some protections in place, anything can be done.

MPPT 450/100 is just a worker and it does what it is told. So, you just need to use a Cerbo or similar and to modify some scripts inside the Cerbo's OS.

What you are looking for is the script dvcc.py from the /opt/victronenergy/dbus-systemcalc-py/delegates folder.

See that there is a function inside named _adjust_battery_operational_limits() which process various quirks of some batteries. You can introduce your own logic there and rise accordingly the float voltage and charging current limit as you need.

Alex

3 comments
2 |3000

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

4711austria avatar image 4711austria commented ·
I use the Cerbo with Node-Red, via Mqtt my ioBroker sets the values.

Just wanted to ask here, if the function inside the MPPT would do a job for me, but unfortunately not.

1 Like 1 ·
nickdb avatar image nickdb ♦♦ commented ·
Just please don't come and post here though when it does not work as planned.

Special systems have special problems and that is usually followed by an unhappy user blaming the product.

Moving to modifications as this has gone off piste and will have gone off support as well.

0 Likes 0 ·
Alex Pescaru avatar image Alex Pescaru nickdb ♦♦ commented ·


Second that!

It's a "do it at your own risk" thing and be very careful with what you are doing as you can damage things...



1 Like 1 ·

Related Resources

Additional resources still need to be added for this topic