BMS dip switch

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Paul Wildsmith
Posts: 18
Joined: Fri May 19, 2023 2:22 pm

A couple of months ago I had 4 hv25 batteries plus invertor installed. I've just added another battery myself, and noticed the dip switch was set at 0. I've now changed it to 3 (the setting for 5 batteries).

I'm getting some anomalous behavior and wondering if the dip should be set back to 0?

Any thoughts?
Dave Foster
Posts: 1303
Joined: Thu Oct 13, 2022 7:21 pm

The dip switch should be set to 3 for 5 batteries, but if it were set to 0 - the BMS would never have known about more than 2 batteries as it wouldn't have been polling them. Fortunately the packs look after their own internal balance, but the pack won’t be balanced properly as the batteries need the poll messages to understand the state of the rest of the pack.

First make sure you are on the latest firmware for both batteries, and BMS (you can see the versions at the inverter panel, in About, Bat Ver).

Then the pack will need to be fully charge and discharged to enable the BMS to learn the limits and give the individual packs time to balance themselves with the rest of the pack, depending on how out of balance they are it may require several weeks before they regain balance.
Paul Wildsmith
Posts: 18
Joined: Fri May 19, 2023 2:22 pm

Thanks, I guess I'm just in the balancing process now
Spearhead
Posts: 2
Joined: Mon Apr 22, 2024 7:16 pm

Dave Foster wrote: Wed Aug 23, 2023 11:39 am The dip switch should be set to 3 for 5 batteries, but if it were set to 0 - the BMS would never have known about more than 2 batteries as it wouldn't have been polling them. Fortunately the packs look after their own internal balance, but the pack won’t be balanced properly as the batteries need the poll messages to understand the state of the rest of the pack.

First make sure you are on the latest firmware for both batteries, and BMS (you can see the versions at the inverter panel, in About, Bat Ver).

Then the pack will need to be fully charge and discharged to enable the BMS to learn the limits and give the individual packs time to balance themselves with the rest of the pack, depending on how out of balance they are it may require several weeks before they regain balance.
Hi can I just confirm, we have just had a Fox ESs system 5.9 with H1 inverter
1 master battery 2900
1 slave batter 2900
Dip Swich @ 0

We are about to add a further Four 2900 slaves.
Do we move Dip Switch to number 3 or 4 ?
Many thanks for advise given
Cheers
Paul
Dave Foster
Posts: 1303
Joined: Thu Oct 13, 2022 7:21 pm

Spearhead wrote: Mon Apr 29, 2024 5:28 pm
Dave Foster wrote: Wed Aug 23, 2023 11:39 am The dip switch should be set to 3 for 5 batteries, but if it were set to 0 - the BMS would never have known about more than 2 batteries as it wouldn't have been polling them. Fortunately the packs look after their own internal balance, but the pack won’t be balanced properly as the batteries need the poll messages to understand the state of the rest of the pack.

First make sure you are on the latest firmware for both batteries, and BMS (you can see the versions at the inverter panel, in About, Bat Ver).

Then the pack will need to be fully charge and discharged to enable the BMS to learn the limits and give the individual packs time to balance themselves with the rest of the pack, depending on how out of balance they are it may require several weeks before they regain balance.
Hi can I just confirm, we have just had a Fox ESs system 5.9 with H1 inverter
1 master battery 2900
1 slave batter 2900
Dip Swich @ 0

We are about to add a further Four 2900 slaves.
Do we move Dip Switch to number 3 or 4 ?
Many thanks for advise given
Cheers
Paul
So just to confirm you will have 1 master (CM) and will have 5 slaves (CS) - in which case you would set the dip switch to ‘4’

The numbering runs as follows:
  • 1 CS, set it to ‘0’
  • 2 CS, set it to ‘1’
  • 3 CS, set it to ‘2’
  • 4 CS, set it to ‘3’
  • 5 CS, set it to ‘4’
  • 6 CS, set it to ‘5’
Spearhead
Posts: 2
Joined: Mon Apr 22, 2024 7:16 pm

:D Outstanding response, clarity’ personified
Thank you
Mark-Averill
Posts: 5
Joined: Sun May 12, 2024 8:46 am

Hi, I have just added a third HV2600 battery to my system.
Followed the instructions, checked the voltage etc. set the dip switch to 1
Before adding the voltage was around 105v, after adding it went up to around 158 so there is a circuit.
On the app the system is now displaying the higher voltage BUT is only showing 5.12kwh capacity.
The two original batteries are at version 1.05, the new battery is at 1.004.
Do they all need to be at the same version? Or will the system resolve the storage anomaly over the next few hours?
Thanks in advance
Dave Foster
Posts: 1303
Joined: Thu Oct 13, 2022 7:21 pm

Mark-Averill wrote: Sun May 12, 2024 9:01 am Hi, I have just added a third HV2600 battery to my system.
Followed the instructions, checked the voltage etc. set the dip switch to 1
Before adding the voltage was around 105v, after adding it went up to around 158 so there is a circuit.
On the app the system is now displaying the higher voltage BUT is only showing 5.12kwh capacity.
The two original batteries are at version 1.05, the new battery is at 1.004.
Do they all need to be at the same version? Or will the system resolve the storage anomaly over the next few hours?
Thanks in advance
You don't mention which app you are using, but generally if you do not have any errors and the voltage is correctly showing (which it is) then your system is fine - there are now a lot of variables that affect your shown capacity - i.e. was the rest of the pack at 50% when you added the new battery, if not it will take it much longer to balance the batteries.

The easiest way to balance the batteries is to charge and discharge them from full to empty over a few cycles - this will happen naturally over time, but can take up to several weeks depending on your use.

On the firmware, you didn't mention whether they were V1 or V2 batteries but either way those firmware versions are old, the most important thing for long term running is that they are all using the same level of firmware - if you email fox service with your inverter serial number and ask them to update your battery firmware, they usually handle that within 48 hours.
Mark-Averill
Posts: 5
Joined: Sun May 12, 2024 8:46 am

Many thanks for the swift response.
I will make contact with fox support to get them to do the necessary… 😀
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