UK Using 3 Fogstar 5.12kWh Energy Server Rack Batteries, cant keep them in sync

Alkaline said:

I"m just wondering why people just don't go to a single 14.3 KW battery and instead go with 3 small 5 KW batteries

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SeaGal said:

I have a 14.3kWh DIY battery myself... so that's the best route for the likes of you and me... but I can imagine that people who are less DIY orientated would want to purchase a pre-built battery pack that comes with some support and warrantee.

In the UK, I am not aware of any pre-made 14.3kW battery packs that can just be purchased off the shelf - let alone be easily transported or installed due to the weight. Maybe they are more common in the USA?

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houseofancients said:

Fogstar is selling the seplos Mason 280 kits

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Oldman2 said:

I have a Solis RAI-3K-48ES-5G AC Coupled Inverter and 3 Fogstar 5.12kWh rack batteries, the Pace BMS in these is set to mimic Pylontec as Fogstar isnt on the Solis list and that seems to be working out just fine.
My problem is 2 of the rack batteries will charge and discharge in sync with each other in percentage terms read from either the batteries screen or from the BMS via PbmsTools V2.5FN. The current discharge and charge remain pretty close to the same on these 2 batteries too when viewed via PbmsTols.
Battery 3 though seems to have a mind of its own, generally lagging behind the other 2 by up to 5% in charging and not taking the same charge current as the other 2.
Even if I charge all 3 together to 100% via solar during the day, by next morning they will be 71%, 71% & 67% As you can see B1 & 2 are still in sync 12hrs later but B3 is way off at 67%.
View attachment 160978
The 3 batteries are in parallel with pos/neg supply cables to opposite ends as in photo. I have tried various other combinations starting with red to battery 3 and black to battery 1, both supply leads to battery 2 and also both to battery 3 with pretty much the same results. Battery 3 always goes out of sync with the other 2 remaining in sync.
This lead me to the conclusion that B3 had a problem so I swopped it for another battery, within 24hrs the replacement B3 is again out of sync.
I tried a constant 39A charge from the Solis.
B1 registered 12.01A 54.10v 70% on PbmsTools
B2 registered 11.64A 54.08v 69%
B3 registered 15.16A 54.03v 71%

Why would B3 get the lions share of charge current? I thought they should be balanced at around 13A each.
So does anyone have any ideas as to how I get the 3 batteries to act as one or close to same?
Anyone here also using multiple Fogstar 5.12kWh server rack batteries? Your experiences may help.

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Drunknspike said:

Hi are they connected up right as we got told to connect them like this picture taken not connected to inverter

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hilltw said:

Afternoon Folks
Would like your opinion on the following scenario.
One Fogstar battery has been running on Growatt SPH3000 for about 12 weeks or so.
Ordered an additional 5kwh to match in October, installed late December.
I have set the inverter to charge the packs to 100% overnight for the past two consecutive nights to attempt a balance.
However, SOC and capacity of the units still vary by about 8Ah when in use.
Voltages are broadly similar.
Can you recommend a few things to check and verify? Or should I stop worrying Your advice appreciated.
Thanks
T.

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Oldman2 said:

I have a Solis RAI-3K-48ES-5G AC Coupled Inverter and 3 Fogstar 5.12kWh rack batteries, the Pace BMS in these is set to mimic Pylontec as Fogstar isnt on the Solis list and that seems to be working out just fine.
My problem is 2 of the rack batteries will charge and discharge in sync with each other in percentage terms read from either the batteries screen or from the BMS via PbmsTools V2.5FN. The current discharge and charge remain pretty close to the same on these 2 batteries too when viewed via PbmsTols.
Battery 3 though seems to have a mind of its own, generally lagging behind the other 2 by up to 5% in charging and not taking the same charge current as the other 2.
Even if I charge all 3 together to 100% via solar during the day, by next morning they will be 71%, 71% & 67% As you can see B1 & 2 are still in sync 12hrs later but B3 is way off at 67%.
View attachment 160978
The 3 batteries are in parallel with pos/neg supply cables to opposite ends as in photo. I have tried various other combinations starting with red to battery 3 and black to battery 1, both supply leads to battery 2 and also both to battery 3 with pretty much the same results. Battery 3 always goes out of sync with the other 2 remaining in sync.
This lead me to the conclusion that B3 had a problem so I swopped it for another battery, within 24hrs the replacement B3 is again out of sync.
I tried a constant 39A charge from the Solis.
B1 registered 12.01A 54.10v 70% on PbmsTools
B2 registered 11.64A 54.08v 69%
B3 registered 15.16A 54.03v 71%

Why would B3 get the lions share of charge current? I thought they should be balanced at around 13A each.
So does anyone have any ideas as to how I get the 3 batteries to act as one or close to same?
Anyone here also using multiple Fogstar 5.12kWh server rack batteries? Your experiences may help.

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Matthew 2 said:

you think have problem using two Fogstar 5.12kWh server rack batteries Battery 1 lions share of charge current 33 A 81% soc and battery 2 1.6 amp 67 % on PbmsTool batteries are in parallel with pos/neg supply cables to opposite ends Battery 1 lions share supply current to 95% and battery 2 1% checked all connection points cable size and length too to each battery

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SeaGal said:

Are batteries reporting same voltage as each other?

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Matthew 2 said:

solar kwh short to much liquid sunshine

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Matthew 2 said:

no and keeps tripping mcb and ben from fogstar looking get the pack ship back and check out pack wiring will report back next week,

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Matthew 2 said:

up date new pack arrived as going to add one more pack to make upto15 kwh with new pack installed and addressing set up shown up Victron vrm new pack at top and mid pack charge up uk but lower pack site 80% 54.432 v all time and will not get 100% >56 v and < 2amp ( only drawing 0.07 amp ) lights on but no one home !? power down pack mcb off and then push button bms shuts down now re powered up the pack push button bms powers up mcb to on battery pack now starts to charge up 100% and also cell BL start as 50mV between cells 40min later now down to 5 mV between cells now discharge test pack 1 and 2 ok but pack 3 will discharge bms not lock out no alarms discharge enabled on bms cam be seen with bms soft ware

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Matthew 2 said:

Up date pack with the charge and discharge problem was shipped back to fogstar and now been overhauled software update and wiring

so one battery had not been charging and discharging and had been over loading the other battery pack but thank to the hard work from Ben from fogstar shorted now

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terribleocotpus said:

Hey - could I ask how you got this working?

What protocol did you set on the batt?
Does the SPH have a way of selecting protocol?

I have a Growatt SPA3000 and it's not talking to my Fogstar-branded Topband batt. I can't see anywhere to customise protocols on the SPA, so curious if the SPH is the same. Trying to work out if its a batt-issue (eg. the BMS in the Topband isn't compat but the BMS in their batt is) or whether the SPA is just a lot more limited than the SPH/SPF series. Ta.

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hilltw said:

Afternoon Folks
Would like your opinion on the following scenario.
One Fogstar battery has been running on Growatt SPH3000 for about 12 weeks or so.
Ordered an additional 5kwh to match in October, installed late December.
I have set the inverter to charge the packs to 100% overnight for the past two consecutive nights to attempt a balance.
However, SOC and capacity of the units still vary by about 8Ah when in use.
Voltages are broadly similar.
Can you recommend a few things to check and verify? Or should I stop worrying Your advice appreciated.
Thanks
T.

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hilltw said:

Further Update...
The two different batteries have developed a considerable percentage difference since installation.
See screenshot, circa 30%

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