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24v 400Ah LifePO4, JBD 200A BMS

Rgulack

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Jan 23, 2022
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Just replaced lead acid batteries (8 x 6v L16 435) in my off grid system with Lynx 24v 400Ah LifePO4 kit w/ JBD 200A BMS.
System has a Midnite Classic 150, 9 x 320 watt panels, and Magnum 4024 PAE. This system has been running flawlessly for the past 5 years with the lead acid batteries.
Needless to say it has been a nightmare getting the system functional, the solar side is working good after several discussions with Lynx and Midnite. The BMS software is convoluted and Chinese manual is a joke. Charging from gen on the Magnum side is not functional, battery goes to 100% in about 5 minutes or so. Have had several tech discussions with Magnum and Lynx, still not resolved. Suggestions?? 😎😎
 
Can you provide a link to the battery?

When you say Lynx I think victron shunt, but I’m guessing it might be a Big Battery name. . .
 
Can you post the settings for the other equipment?

The Magnum is prob still thinking it’s a lead acid with different charge parameters.

As for the JBD and Bluetooth software, have you tried the Overkill app? It should work without issues on JBD units.
 
1. The Xiaoxiang Electric app (recommended control app for the BMS). Battery goes to 100% on this app.

2. Float is Set to 26.4 volts via the ARC remote panel. There isn't a setting to set the Bulk charge rate except for a percentage which is currently set to 60%.

Actual kit purchased is 48v 200Ah. We configured for 24v 400 Ah at this point as we plan on upgrading to a Victron 48v system in the future.

Got Overkill app. Wonderful in comparison to other app. 😎😎
 
I like to use 3.45v per cell for bulk charging. This would be 27.6v it’s a very conservative setting.

I’d try bumping up that float voltage until the generator continues dump power into the voltage.

I’m guessing that magnum is based off voltage for SOC which doesn’t work for your new pack unless cells get above 3.4v

I do recommend disabling “balance only when charging” and start balancing at 3.4v. In the settings.
 
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If you start hitting high voltage disconnect alarms drop your bulk to 3.375-3.400 and let it ride a while. Then start increasing your bulk voltage until you get to 3.45.
 
With the overkill app can you do some screen shots of the default settings?
 
740GLE
Will change that setting, however Magnum recommended setting the final charge to Silent with the rebulk at 27.6. To my understanding that means that Float is skipped.
The Magnum is based off Voltage for charging.
The BMS is set to balance all the time, will change that voltage to 3.4 however.

Partimewages
Previously, we were getting Cell Overcharge Protection kicking in from both Solar and Generator. The BMS was configured for 45ah, not 400ah. Changing that seems to have fixed the issue with Solar charging.
 
I’ve got what may be a dumb question … on the JBD 200A BMS … when it is wired in correctly, and settings as recommended have been entered into the solar controller and the inverter/charger, should the BMS not generate its own settings that are correct for the battery config? Or does one have to mess with the BMS settings?
 
Unless you have the BMS talking to the SCC, the BMS is safety settings, and the SCC is just to get the charge up, so bulk needs to be less than over voltage protection settings of the BMS

From those BMS settings, cell over voltage protection of 3.75 that is pretty aggressive, I’d dial that back to 3.6. This would then equate to a SCC bulk of 28.8 or less. Personally I set me my SCC to 3.45/cell or 27.6v. So in theory the BMS will never get into over voltage protection.

What SCC?
 
Unless you have the BMS talking to the SCC, the BMS is safety settings, and the SCC is just to get the charge up, so bulk needs to be less than over voltage protection settings of the BMS

From those BMS settings, cell over voltage protection of 3.75 that is pretty aggressive, I’d dial that back to 3.6. This would then equate to a SCC bulk of 28.8 or less. Personally I set me my SCC to 3.45/cell or 27.6v. So in theory the BMS will never get into over voltage protection.

What SCC?
Midnite Classic 150
 
What about the Capacity settings? The remote panel on the Magnum has always been merely a guesstimate. If possible, It would be nice to see the SoC on Overkill be at least mostly Accurate.

The way it is set up currently, 100% is 3.5v per cell or 28v for the total, with the Cell full Voltage at 3.45v. It just seems like that needs tweaking.
 

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A BMS tracking SOC has always been hit or miss so fine tuning to track it wasn’t my concern.

If current tapers off and all cells are 3.45v then many consider that 100%.

A proper shunt is ideal for more accurate SOC tracking.
 
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