rsaeon
Patron
Taking a detour from:
techenclave.com
Led me to exploring this option. Most 48V server rack style batteries available abroad are in a 16S configuration and having learned my inverter charges at 14.2V per 12V battery, for a total of 56.8V, divided by 16 resulting in a per cell voltage of 3.55V which is pretty good for a LiFePO4. Bumping it up to 14.6V gives us 3.65V which is pretty much the recommended charging voltage for this chemistry. Float at 13.9V works out to be 3.475V which is a little over the 3.4V recommendation:
diysolarforum.com
The best option of course would be to build my own battery with a kit from MDS Enterprises who pride themselves as selling only the highest grade, best of the batch LiFePO4 cells:
techenclave.com
That wasn't an option for me partly because I don't have that kind of funding and actually well that's the entire reason. MuscleGrid's products are available on Amazon with no-cost emi and seeing how I just got out of a EMI hole it made sense to jump right back in.
Considering how expensive these things are, this one sold by MuscleGrid can't be anything but a very low grade, bottom-of-the-batch rebranded/refurbished/old-stock product. Which is perfectly fine, your first ten thousand batteries are your worst anyway. But seriously, I knew it wasn't going to be the best but that it'll probably be good enough — and way better than any lead acid FLA/AGM option.
So obviously it had to arrive damaged, dented:
![photo_2024-01-04 19.20.55.jpeg photo_2024-01-04 19.20.55.jpeg](https://techenclave.com/data/attachments/184/184429-83c8fb6a5de5d6bbbabcf8a426d15ec0.jpg)
But first, the specifications:
![photo_2024-01-04 19.20.56.jpeg photo_2024-01-04 19.20.56.jpeg](https://techenclave.com/data/attachments/184/184430-2c3d3d8df5cbc6f2158149af7461dca4.jpg)
In case it's not clear, this is supposed to be a 16S unit (but it's not, its 15S as photos will later show).
![photo_2024-01-04 19.20.57.jpeg photo_2024-01-04 19.20.57.jpeg](https://techenclave.com/data/attachments/184/184431-23bb6b4cbc3341c76d5d0acf3259ad77.jpg)
One bent hand grip. Nothing a hammer can't fix.
![photo_2024-01-04 19.20.58.jpeg photo_2024-01-04 19.20.58.jpeg](https://techenclave.com/data/attachments/184/184432-9ee7268dc0009bfc5744d4ef9a87b232.jpg)
Two bent hand grips. I wasn't planning on keeping this enclosure anyway, I just want the cells.
![photo_2024-01-04 19.20.59.jpeg photo_2024-01-04 19.20.59.jpeg](https://techenclave.com/data/attachments/184/184433-de9396cb16db0392bedea1f110ddc39a.jpg)
125A DC circuit breaker, that's good to see and reuse in my own pack.
Removing 15 screws reveals the insides:
![photo_2024-01-04 19.21.00.jpeg photo_2024-01-04 19.21.00.jpeg](https://techenclave.com/data/attachments/184/184434-82a6c274dca42e6eb3dd7cf84217efbe.jpg)
Tidy wiring, which was I guess is the bare minimum standard you can expect.
![photo_2024-01-04 19.21.01.jpeg photo_2024-01-04 19.21.01.jpeg](https://techenclave.com/data/attachments/184/184435-f87a7758442a9b00bd8d4148fb3c76fe.jpg)
BMS is an older unit from Shinwa:
Unfortunately while it may support a 16S configuration, it was built for a 15S one:
![photo_2024-01-04 19.21.02.jpeg photo_2024-01-04 19.21.02.jpeg](https://techenclave.com/data/attachments/184/184438-2c29764a3c3cc568293d26d0c3fc44c0.jpg)
The connector doesn't include the B16 pins. Maybe it could be replaced or rewired or reprogrammed for a 16S configuration, I'll find that out later when I reuse this for a powerwall project.
The battery pack itself:
![photo_2024-01-04 19.21.03.jpeg photo_2024-01-04 19.21.03.jpeg](https://techenclave.com/data/attachments/184/184440-50dbe5bfbbcfc915bda4d059411111cf.jpg)
That's a lot of wires! There's EIGHT thermal sensors in there, probably to make sure nothing overheats — either because this 15S configuration was meant for Li-Ion chemistry originally, or they expect 48V inverters to overcharge this 15S pack, at 14.4V that's a per cell voltage of 3.85V which is well out of spec for LiFePO4.
![photo_2024-01-04 19.21.03 (1).jpeg photo_2024-01-04 19.21.03 (1).jpeg](https://techenclave.com/data/attachments/184/184446-b3b060b28df43774bfbad00dc407734f.jpg)
Yeah, that's a 15S pack.
![photo_2024-01-04 19.21.05.jpeg photo_2024-01-04 19.21.05.jpeg](https://techenclave.com/data/attachments/184/184447-4a969e4aa884c77cd50ae41114939b12.jpg)
This information is mostly useless, nothing comes up in battery databases or web searches.
![photo_2024-01-04 19.21.06.jpeg photo_2024-01-04 19.21.06.jpeg](https://techenclave.com/data/attachments/184/184448-2166a17ded61dc802ef3646ee80a8016.jpg)
But this sticker reveals it's a Narada Power FE105C cell. The C indicates it's a lower-grade cell, more about that here:
And it also indicates it's a 105Ah battery, not 120Ah as claimed by MuscleGrid.
To recap, these are facts about the MuscleGrid 48V 120Ah LiFePO4 Server Rack Battery:
Todo:
Working with Inverter/UPS Lead Acid Batteries
I'm going to consolidate my experiments and adventures with inverter batteries here. Previous posts on the topic: https://techenclave.com/threads/diy-wi-fi-battery-monitor-for-inverters-ups-iot-lead-acid-battery.217210/...
![techenclave.com](https://techenclave.com/data/assets/logo/ic_launcher_192.png)
Led me to exploring this option. Most 48V server rack style batteries available abroad are in a 16S configuration and having learned my inverter charges at 14.2V per 12V battery, for a total of 56.8V, divided by 16 resulting in a per cell voltage of 3.55V which is pretty good for a LiFePO4. Bumping it up to 14.6V gives us 3.65V which is pretty much the recommended charging voltage for this chemistry. Float at 13.9V works out to be 3.475V which is a little over the 3.4V recommendation:
![diysolarforum.com](/proxy.php?image=https%3A%2F%2Fwww.mobile-solarpower.com%2Fuploads%2F1%2F2%2F9%2F6%2F12964626%2Fimg-20190331-124124-456_1_orig.jpg&hash=0fedf0fd44e478588f7afc58a7e7d934&return_error=1)
Recommended Charge Profile for DIY LiFePO4 Batteries *Sticky Post*
12V 4S LiFePO4 Battery w/ BMS: Absorption: 14.5V Float: 13.6V Inverter Cut-off: 10.7V-12V (depending on size of load and voltage drop etc) 24V 8S LiFePO4 Battery w/ BMS Absorption: 29V Float: 27.2V Inverter Cut-off: 21.4V-24V 48V 16S LiFePO4 Battery w/ BMS Absorption: 58V Float: 54.4V...
![diysolarforum.com](/proxy.php?image=https%3A%2F%2Fwww.mobile-solarpower.com%2Fuploads%2F1%2F2%2F9%2F6%2F12964626%2Ffinal-favicon_orig.png&hash=7ab11bc71dbaf47e67e2a26992657000&return_error=1)
The best option of course would be to build my own battery with a kit from MDS Enterprises who pride themselves as selling only the highest grade, best of the batch LiFePO4 cells:
Where can I buy LifePo4 grade A prismatic cells in India?
I come across a lot of IndiaMart vendors selling LifePo4 cells and I don't know which ones are reliable. I can't find anyone selling known brands like EVE, CATL or CALB. If any of you have purchased them from Alibaba do share your experience.
![techenclave.com](https://techenclave.com/data/assets/logo/ic_launcher_192.png)
That wasn't an option for me partly because I don't have that kind of funding and actually well that's the entire reason. MuscleGrid's products are available on Amazon with no-cost emi and seeing how I just got out of a EMI hole it made sense to jump right back in.
Considering how expensive these things are, this one sold by MuscleGrid can't be anything but a very low grade, bottom-of-the-batch rebranded/refurbished/old-stock product. Which is perfectly fine, your first ten thousand batteries are your worst anyway. But seriously, I knew it wasn't going to be the best but that it'll probably be good enough — and way better than any lead acid FLA/AGM option.
So obviously it had to arrive damaged, dented:
![photo_2024-01-04 19.20.55.jpeg photo_2024-01-04 19.20.55.jpeg](https://techenclave.com/data/attachments/184/184429-83c8fb6a5de5d6bbbabcf8a426d15ec0.jpg)
But first, the specifications:
![photo_2024-01-04 19.20.56.jpeg photo_2024-01-04 19.20.56.jpeg](https://techenclave.com/data/attachments/184/184430-2c3d3d8df5cbc6f2158149af7461dca4.jpg)
In case it's not clear, this is supposed to be a 16S unit (but it's not, its 15S as photos will later show).
![photo_2024-01-04 19.20.57.jpeg photo_2024-01-04 19.20.57.jpeg](https://techenclave.com/data/attachments/184/184431-23bb6b4cbc3341c76d5d0acf3259ad77.jpg)
One bent hand grip. Nothing a hammer can't fix.
![photo_2024-01-04 19.20.58.jpeg photo_2024-01-04 19.20.58.jpeg](https://techenclave.com/data/attachments/184/184432-9ee7268dc0009bfc5744d4ef9a87b232.jpg)
Two bent hand grips. I wasn't planning on keeping this enclosure anyway, I just want the cells.
![photo_2024-01-04 19.20.59.jpeg photo_2024-01-04 19.20.59.jpeg](https://techenclave.com/data/attachments/184/184433-de9396cb16db0392bedea1f110ddc39a.jpg)
125A DC circuit breaker, that's good to see and reuse in my own pack.
Removing 15 screws reveals the insides:
![photo_2024-01-04 19.21.00.jpeg photo_2024-01-04 19.21.00.jpeg](https://techenclave.com/data/attachments/184/184434-82a6c274dca42e6eb3dd7cf84217efbe.jpg)
Tidy wiring, which was I guess is the bare minimum standard you can expect.
![photo_2024-01-04 19.21.01.jpeg photo_2024-01-04 19.21.01.jpeg](https://techenclave.com/data/attachments/184/184435-f87a7758442a9b00bd8d4148fb3c76fe.jpg)
BMS is an older unit from Shinwa:
Unfortunately while it may support a 16S configuration, it was built for a 15S one:
![photo_2024-01-04 19.21.02.jpeg photo_2024-01-04 19.21.02.jpeg](https://techenclave.com/data/attachments/184/184438-2c29764a3c3cc568293d26d0c3fc44c0.jpg)
The connector doesn't include the B16 pins. Maybe it could be replaced or rewired or reprogrammed for a 16S configuration, I'll find that out later when I reuse this for a powerwall project.
The battery pack itself:
![photo_2024-01-04 19.21.03.jpeg photo_2024-01-04 19.21.03.jpeg](https://techenclave.com/data/attachments/184/184440-50dbe5bfbbcfc915bda4d059411111cf.jpg)
That's a lot of wires! There's EIGHT thermal sensors in there, probably to make sure nothing overheats — either because this 15S configuration was meant for Li-Ion chemistry originally, or they expect 48V inverters to overcharge this 15S pack, at 14.4V that's a per cell voltage of 3.85V which is well out of spec for LiFePO4.
![photo_2024-01-04 19.21.03 (1).jpeg photo_2024-01-04 19.21.03 (1).jpeg](https://techenclave.com/data/attachments/184/184446-b3b060b28df43774bfbad00dc407734f.jpg)
Yeah, that's a 15S pack.
![photo_2024-01-04 19.21.05.jpeg photo_2024-01-04 19.21.05.jpeg](https://techenclave.com/data/attachments/184/184447-4a969e4aa884c77cd50ae41114939b12.jpg)
This information is mostly useless, nothing comes up in battery databases or web searches.
![photo_2024-01-04 19.21.06.jpeg photo_2024-01-04 19.21.06.jpeg](https://techenclave.com/data/attachments/184/184448-2166a17ded61dc802ef3646ee80a8016.jpg)
But this sticker reveals it's a Narada Power FE105C cell. The C indicates it's a lower-grade cell, more about that here:
And it also indicates it's a 105Ah battery, not 120Ah as claimed by MuscleGrid.
To recap, these are facts about the MuscleGrid 48V 120Ah LiFePO4 Server Rack Battery:
- It arrived damaged, despite being packed in a wooden crate
- It's 15S not 16S
- It's 105Ah not 120Ah
- It uses 'C' grade/batch cells from Narada Power
- It'll probably last ten years or more despite all of this (benefits of LiFePO4 chemistry)
Todo:
- Purchase a single cell to rebuild this as a 16S pack
- Build or buy a 16S BMS
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