Teardown & Rebuild of a MuscleGrid LiFePO4 Server Rack ...

octal777 said:

2. What is powered by these inverters are they typical home loads?

Link to Energyland

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This battery will be powering a few 'servers' that I run at home and need to keep online. Occasionally, it will be used for a water pump during extended power cuts.

octal777 said:

1. Are you shifting to LiFePO4 primarily due to the longevity or do plan to add more cycles by probably adding a solar charge controller?

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Both.

The decision was mostly constrained by what was available with Amazon's No Cost EMI. It was either Luminous Red Charge FLAs or this MuscleGrid battery. Before purchasing it, I suspected this wasn't really a 120Ah battery and that it couldn't possibly be using new or high quality cells but went ahead anyway because of the other benefits of LiFePO4. I intend to build my own battery packs in the future so taking this one apart was a learning experience.

The load is a continuous 1kW, so I would eventually like to shift to an offgrid solar installation at some point in the future with used panels, they're often sold at less than half the cost of new ones.

octal777 said:

3. What BMS are you considering ? The JK BMS are recommended quite a lot due to their active balancing capability. I found the Off Grid Garage on Youtube quite helpful

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I've been watching that channel on and off over the months leading to this purchase, along with Will Prowse, DavidPoz, Lithium Solar and Jehu Garcia. We're often behind the technology curve in India but with LiFePO4, it is nice to learn from the mistakes/pitfalls that the early adopters in other countries have went through.

Right now, I'm leaning towards making my own top-balancing BMS, a simple ESP running Tasmota that will discharge each cell through a power resistor for 30 seconds at time when voltages go over 3.6V. It's the basic concept of Stuart Pittaway's original diyBMS but without the isolated I2C bus. I want to use mass produced modules instead of custom-made PCBs. Tasmota's integration with MQTT would be very useful in creating NodeRed flows that I'll use to trigger shutdowns when the batteries get low.

I'll be using one ESP module for every four cells. They'll log data through MQTT/NodeRed into InfluxDB and from there I can generate nice graphs with Grafana. It's not as self contained as the diyBMS, but it's a system I'll have complete control over. I administer Tasmota devices with Ansible so it's easy to make changes and I have automated daily backups of each device's configuration setup with NodeRed. My backup strategy for config files is to keep last thirty days backups and then one for every month prior. The unneeded backup files are deleted with a daily cron job:

1 0 * * * /usr/bin/find /backups -type f -mtime +30 ! -name '*01-*' -exec /bin/rm {} \;

The backup files are named YYYYMMDD-indentifier so the *01-* part keeps only the backup made on the 1st of each month before and only files older than 30 days are deleted.

For over-current and short-circuit protection, I'll use that DC rated MCB. I might forego under-voltage protection and rely on software controlled shutdowns to reduce the load. I might use a DC-rated contactor if I can find one or maybe a power mosfet as a battery disconnect. I need to do more research on this.

I have a battery equalizer that I purchased from Banggood, I think I'll be using that for active balancing (four groups of four cells each):

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octal777 said:

1. I have a 12V Inverter meant for Lead Acid upgrading this makes no sense might as well move to a 48V system from Ashapower or similar

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Ashapower really appears to be the highest 'Make In India' standard for this market, with UTL being a very good price-conscious alternative. There are interviews on youtube with the engineers from both companies and it's hard not to be impressed.

ze_cook said:

I've been planning to get a lifepo4 battery pack for a while now. Problem with cheap batteries are mismatched cells, one cell might've degraded more, will drop below threshold faster and the BMS will cut the entire battery off. Even if the individual cells are rated at 105, you might not get 105 with the entire battery. Only way to know for sure is a capacity test with cell voltage logging.

I want to get a capacity tester from banggood, but they're too expensive (8k ish) for my one off case. Please keep updating the thread.

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Yes, I suspect this is an unbalanced battery nowhere near the rated 105Ah capacity and that is the reason for the lower pricing compared to other brands. Older reviews mentioning getting only 50Ah from the battery and I really hope it's not that bad. MuscleGrid keeps removing the older product pages whenever someone posts a negative review, which is part of the reason why this thread is here and not on Amazon.

For logging, again, Tasmota on a ESP with a INA219 module costs less than Rs 500 and is plenty accurate, so all I need is a low-voltage high-amperage DC load to discharge the batteries.


I've updated my Todo:

1. Build a high amp battery charger for 3.65V
2. Purchase a battery tester and do a charge/discharge test for each cell
3. Purchase a single cell to rebuild this as a 16S pack
4. Build or buy a 16S BMS

This battery will be powering a few 'servers' that I run at home and need to keep online. Occasionally, it will be used for a water pump during extended power cuts.Both.The decision was mostly constrained by what was available with Amazon's No Cost EMI. It was either Luminous Red Charge FLAs or this MuscleGrid battery. Before purchasing it, I suspected this wasn't really a 120Ah battery and that it couldn't possibly be using new or high quality cells but went ahead anyway because of the other benefits of LiFePO4. I intend to build my own battery packs in the future so taking this one apart was a learning experience.The load is a continuous 1kW, so I would eventually like to shift to an offgrid solar installation at some point in the future with used panels, they're often sold at less than half the cost of new ones.I've been watching that channel on and off over the months leading to this purchase, along with Will Prowse, DavidPoz, Lithium Solar and Jehu Garcia. We're often behind the technology curve in India but with LiFePO4, it is nice to learn from the mistakes/pitfalls that the early adopters in other countries have went through.Right now, I'm leaning towards making my own top-balancing BMS, a simple ESP running Tasmota that will discharge each cell through a power resistor for 30 seconds at time when voltages go over 3.6V. It's the basic concept of Stuart Pittaway's original diyBMS but without the isolated I2C bus. I want to use mass produced modules instead of custom-made PCBs. Tasmota's integration with MQTT would be very useful in creating NodeRed flows that I'll use to trigger shutdowns when the batteries get low.I'll be using one ESP module for every four cells. They'll log data through MQTT/NodeRed into InfluxDB and from there I can generate nice graphs with Grafana. It's not as self contained as the diyBMS, but it's a system I'll have complete control over. I administer Tasmota devices with Ansible so it's easy to make changes and I have automated daily backups of each device's configuration setup with NodeRed. My backup strategy for config files is to keep last thirty days backups and then one for every month prior. The unneeded backup files are deleted with a daily cron job:The backup files are namedso thepart keeps only the backup made on the 1st of each month before and only files older than 30 days are deleted.For over-current and short-circuit protection, I'll use that DC rated MCB. I might forego under-voltage protection and rely on software controlled shutdowns to reduce the load. I might use a DC-rated contactor if I can find one or maybe a power mosfet as a battery disconnect. I need to do more research on this.I have a battery equalizer that I purchased from Banggood, I think I'll be using that for active balancing (four groups of four cells each):Ashapower really appears to be the highest 'Make In India' standard for this market, with UTL being a very good price-conscious alternative. There are interviews on youtube with the engineers from both companies and it's hard not to be impressed.Yes, I suspect this is an unbalanced battery nowhere near the rated 105Ah capacity and that is the reason for the lower pricing compared to other brands. Older reviews mentioning getting only 50Ah from the battery and I really hope it's not that bad. MuscleGrid keeps removing the older product pages whenever someone posts a negative review, which is part of the reason why this thread is here and not on Amazon.For logging, again, Tasmota on a ESP with a INA219 module costs less than Rs 500 and is plenty accurate, so all I need is a low-voltage high-amperage DC load to discharge the batteries.I've updated my Todo:

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