anybody have battery glitches when adding batteries….we added 3 batts to the deye hv bos system with 4 in…apparently batts have to be the same charge when all running together… we had to use 1 of original 4 to start with 3 new ones (inverter only starts at 160V). it seemed the new batts were 100pct but now the bms goes from 50soc to 100pct in afew minutes,.. i guess the bms thinks batts are full but they not.. any experience with this.. have to charge individual batts to 100pct and then re assemble…

Sounds about right, always better to have all the batteries charged and absorbed fully to 100% before connecting together.

Edited October 17, 20232 yr by WannabeSolarSparky

anybody klnow how to charge a deye HV battery individually...

On 2023/10/17 at 7:28 AM, craig shaw said:

anybody have battery glitches when adding batteries….

In another thread with the same topic I wrote: When it comes to electrically connecting new with old, make sure new and old have as close as possible the same SOC. Otherwise you will get momentarily a very high current until the SOC are equalized.

If the battery you want to connect has actually a lower SOC, wait for the existing ones to discharge to the same level. You may temporarily connect with car battery jumper cables. Then recharge all together.

5 minutes ago, Beat said:

In another thread with the same topic I wrote: When it comes to electrically connecting new with old, make sure new and old have as close as possible the same SOC. Otherwise you will get momentarily a very high current until the SOC are equalized.

If the battery you want to connect has actually a lower SOC, wait for the existing ones to discharge to the same level. You may temporarily connect with car battery jumper cables. Then recharge all together.

For sure not the way many installers go about adding another battery. 

In the Deye HV manual...
 

Quote

Note about BOS-G and GB-L battery packs before installation

Please confirm the battery batch before using the battery. And then select the same
batch in priority, which can be identified according to the barcode
(00803000B128036300: The ninth letter is for the year of production, in which the
A for 2022 and the B for the 2023, the 10th letter is for the month and the 11th
and 12th for the date of production.)

Used batteries can not be mixed with new batteries. Batteries that have been used
but belong to different groups also can not be mixed. If you want to increase the
number of batteries in the original cluster to increase the power, please contact
the factory technical staff, and then operate under the guidance of the staff.

 

5 hours ago, Kalahari Meerkat said:

In the Deye HV manual...
 

 

thanks - we have 8 batts now - we charged and ran in two sets of 4.. we now let them equalise each to voltage by connecting them (off load and not in circuit) - we got the voltage to 53.36-53,40 ranges for the 8 - (like a waterfall). we will run and disconnect some time for them to settle and feed each other off load and not in circuit - might need a few hours just sitting..

the SOC of the two sets were exactly the same 96,9% but voltages differed by 0,03-0,04V.. 6 of them are exactly 53,36 and only two are 53.37 and 53,40V.  its like 2 of them are HIGH achievers...

ps they came from 2 batches 23 march and 28 march.  (4 each)

DEYE DOES NOT HAVE A LARGE HV CHARGER HERE - BALANCING IS A BUGGER - big learning curve- HV batts on a deye 20kw - have to buy them in batches of 4... as the inverter does not turn on (DC circuit) with 3.... (160V) even with grid ON

Lots of lesson learnt with HV system

6 hours ago, Scorp007 said:

For sure not the way many installers go about adding another battery. 

thanks - we have 8 batts now - we charged and ran in two sets of 4.. we now let them equalise each to voltage by connecting them (off load and not in circuit) - we got the voltage to 53.36-53,40 ranges for the 8 - (like a waterfall). we will run and disconnect some time for them to settle and feed each other off load and not in circuit - might need a few hours just sitting..

the SOC of the two sets were exactly the same 96,9% but voltages differed by 0,03-0,04V.. 6 of them are exactly 53,36 and only two are 53.37 and 53,40V.  its like 2 of them are HIGH achievers...

ps they came from 2 batches 23 march and 28 march.  (4 each)

DEYE DOES NOT HAVE A LARGE HV CHARGER HERE - BALANCING IS A BUGGER - big learning curve- HV batts on a deye 20kw - have to buy them in batches of 4... as the inverter does not turn on (DC circuit) with 3.... (160V) even with grid ON

Lots of lesson learnt with HV system

6 hours ago, Beat said:

In another thread with the same topic I wrote: When it comes to electrically connecting new with old, make sure new and old have as close as possible the same SOC. Otherwise you will get momentarily a very high current until the SOC are equalized.

If the battery you want to connect has actually a lower SOC, wait for the existing ones to discharge to the same level. You may temporarily connect with car battery jumper cables. Then recharge all together.

PS - they only a week old (the first 4) then i decided to add more...to get rid of eskom overnight...i couldnt bear taking 18kwh from eskom overnight...

On 2023/10/17 at 8:02 AM, WannabeSolarSparky said:

Sounds about right, always better to have all the batteries charged and absorbed fully to 100% before connecting together.

deye or Solare Europe - no one has a individual HV batt charger tester - a big business idea to balance batts here. But Pierre the sparky connects them off load and then they slowly equalise themselves - need 4-12 hrs though

Please, by connecting without load, do you mean just disconnecting from the inverter with the BMS switched on, or simply connecting and disconnecting from the inverter with the BMS switched off?

Thank you.

8 hours ago, Jan_Ba said:

Please, by connecting without load, do you mean just disconnecting from the inverter with the BMS switched on, or simply connecting and disconnecting from the inverter with the BMS switched off?

Thank you.

I presume when you say with the BMS off you imply the battery is switched off. If switched of the BMS disconnects the battery negative from the output terminal. To thus balance off load and batteries disconnected on can balance the batteries to close to same SOC. This then help to get all batteries close to same SOC and it will be quicker than to rely on the BMSes of to balance.

Just one point. Use cable of about 3m between the batteries to reduce the current from the high SOC to the batteries with low SOC. For 100Ah batteries 16 Sq mm would be good enough. There will only be about 35A flowing and for less than 10min. This obvious for balancing 2 batteries.

On 2023/10/17 at 7:28 AM, craig shaw said:

anybody have battery glitches when adding batteries….we added 3 batts to the deye hv bos system with 4 in…apparently batts have to be the same charge when all running together… we had to use 1 of original 4 to start with 3 new ones (inverter only starts at 160V). it seemed the new batts were 100pct but now the bms goes from 50soc to 100pct in afew minutes,.. i guess the bms thinks batts are full but they not.. any experience with this.. have to charge individual batts to 100pct and then re assemble…

This is a known issue with DEYE HV systems (especially BOS/Growatt/Shoto/Seplos HV stacks) when adding new batteries to an existing stack. What you're seeing (SOC jumping 50% to 100% in minutes) is classic BMS desynchronisation.

HV stacks require all modules to be at the same voltage when connected. If one module is even 1–2 V higher, the BMS will assume a “full” condition and skip charging. If lower, it will be pushed hard and the SOC will jump incorrectly. Your inverter needs ±160–170 V to wake the HV bus, so you used one of the old four (correct). But even though the new 3 batteries were “100%”, their actual voltage wasn’t identical to the old ones. Because of this mismatch, the master BMS recalibrated SOC incorrectly, often showing things like 50% to 100% in minutes 1.Stopping charge early 2.Sudden drops once loads run. The BMS always trusts cell voltage, not SOC memory.

You must charge each module individually to exactly the same voltage (not just “100%”soc).

Ideally:

Charge every module to full (3.40–3.45 V per cell) using a single-module charger Let it sit for 20–30 minutes to stabilize Make sure every module is within ±0.02 V Re-stack them.Power up the inverter. Let the BMS do a full charge 》 balance 》 rest cycle. This forces the stack to 1.Resync upper cutoff 2.Relearn SOC curve.3.Re-enable correct coulomb tracking

It is so great to be part of @TaliaB on line university.

Thanks for sharing. No substitute for real life knowledge.

+1