Hi,
I was looking for a good deal on a battery that I could actually order and receive quickly back in June. I've settled on BigBattery's LAMA. It seemed like a good deal, provided that everything was as advertised. I'll tell you guys what happened and request your comments about it.
More information about the battery is at https://bigbattery.com/products/48v-lama/.
The battery was shipped quickly and was delivered 10 days after the order. Unfortunately, the R&L driver delivered the battery to the wrong address and I've got some lab equipment shipment instead. Luckily, the situation was rectified the next day and I've got the correct shipment. However, it looked like the shipment was opened, so, it would be impossible to say whether the defects I saw were there initially or were created by the person who received my battery the previous day.
I immediately saw something was off with the battery.
1. The battery dimensions and weight were different than what was stated on their website. BigBattery later corrected their website, however, their specs PDF still has the wrong dimensions.
2. The battery was missing screws, had stripped, mismatching screws and minor cosmetic issues. It is possible the first guy who had it tried to take it apart.
3. It felt like something was hitting the battery wall when I tried to move the battery around.
I tried to call and email BigBattery customer support, however, the only way I was able to reach them quickly and reliably was the live chat on their website. They did respond to my email a few days later, but it was kind of late. Anyway, they said that their website was wrong about dimensions but they did agree to replace the battery free of charge due to the missing screws and such.
The whole process took a couple of weeks but I finally had my replacement in July. They did keep the anderson connector that came with the battery that I sent back but they did graciously agree to FedEx one over quickly.
The new battery was in much better shape but I still could feel something hitting the wall of the battery when it was moved around. BigBattery support did suggest I open it and see what it was. It turned out to be a long piece of thick wire running down the battery that was strangely not secured.
Once I had everything ready, I commenced with the testing.
One minor issue that I ran into was the current display on the battery. It always shows random numbers that change occasionally. Whatever the reading is, it is not current. The voltage display does work correctly, so, at least there is that. I asked BigBattery support about it and they suggested I reset the BMS. I followed their instructions but it did not fix the issue with the current display.
The second issue I ran into was lack of SoC data in their specs sheet and their website. They did say that 10% was 43V and 20% was 44.8V. They said "We have a sheet that we use here that is as close as we know for the batteries, but we do not offer that out to customers as it is not 100% accurate". They also said they don't have any battery performance characteristics charts.
I did all the testing with Growatt SPF 3000 TL LVM ES and this shunt meter. Numbers coming out of the Growatt were off, possibly due to incorrect battery voltage and current readings. I think the shunt meter did a much better job.
I configured the Growatt to switch to utility once the SoC was roughly 20%. I would reset the shunt meter roughly when the battery just started discharging in the evening. I would come back in the morning and check what the meter reading was.
Test #1:
Test #2:
(ignore the 0.7A current draw, it seems to be an issue with the Growatt, it does not invalidate the test)
According to my calculations, the capacity of this battery is better than the advertised 5.3 kwh. Someone correct me if I am wrong.
I tried to get BigBattery support to tell me what cells were in the battery, however, they wouldn't say much except that they are "A123 lithium iron phosphate cells".
It was time to take a look inside to get more answers.
To be continued...
I was looking for a good deal on a battery that I could actually order and receive quickly back in June. I've settled on BigBattery's LAMA. It seemed like a good deal, provided that everything was as advertised. I'll tell you guys what happened and request your comments about it.
More information about the battery is at https://bigbattery.com/products/48v-lama/.
The battery was shipped quickly and was delivered 10 days after the order. Unfortunately, the R&L driver delivered the battery to the wrong address and I've got some lab equipment shipment instead. Luckily, the situation was rectified the next day and I've got the correct shipment. However, it looked like the shipment was opened, so, it would be impossible to say whether the defects I saw were there initially or were created by the person who received my battery the previous day.
I immediately saw something was off with the battery.
1. The battery dimensions and weight were different than what was stated on their website. BigBattery later corrected their website, however, their specs PDF still has the wrong dimensions.
2. The battery was missing screws, had stripped, mismatching screws and minor cosmetic issues. It is possible the first guy who had it tried to take it apart.
3. It felt like something was hitting the battery wall when I tried to move the battery around.
I tried to call and email BigBattery customer support, however, the only way I was able to reach them quickly and reliably was the live chat on their website. They did respond to my email a few days later, but it was kind of late. Anyway, they said that their website was wrong about dimensions but they did agree to replace the battery free of charge due to the missing screws and such.
The whole process took a couple of weeks but I finally had my replacement in July. They did keep the anderson connector that came with the battery that I sent back but they did graciously agree to FedEx one over quickly.
The new battery was in much better shape but I still could feel something hitting the wall of the battery when it was moved around. BigBattery support did suggest I open it and see what it was. It turned out to be a long piece of thick wire running down the battery that was strangely not secured.
Once I had everything ready, I commenced with the testing.
One minor issue that I ran into was the current display on the battery. It always shows random numbers that change occasionally. Whatever the reading is, it is not current. The voltage display does work correctly, so, at least there is that. I asked BigBattery support about it and they suggested I reset the BMS. I followed their instructions but it did not fix the issue with the current display.
The second issue I ran into was lack of SoC data in their specs sheet and their website. They did say that 10% was 43V and 20% was 44.8V. They said "We have a sheet that we use here that is as close as we know for the batteries, but we do not offer that out to customers as it is not 100% accurate". They also said they don't have any battery performance characteristics charts.
I did all the testing with Growatt SPF 3000 TL LVM ES and this shunt meter. Numbers coming out of the Growatt were off, possibly due to incorrect battery voltage and current readings. I think the shunt meter did a much better job.
I configured the Growatt to switch to utility once the SoC was roughly 20%. I would reset the shunt meter roughly when the battery just started discharging in the evening. I would come back in the morning and check what the meter reading was.
Test #1:
Test #2:
(ignore the 0.7A current draw, it seems to be an issue with the Growatt, it does not invalidate the test)
According to my calculations, the capacity of this battery is better than the advertised 5.3 kwh. Someone correct me if I am wrong.
I tried to get BigBattery support to tell me what cells were in the battery, however, they wouldn't say much except that they are "A123 lithium iron phosphate cells".
It was time to take a look inside to get more answers.
To be continued...