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Inside the Big Battery 48v BDGR 2.1 kWH Battery Pack

bluetrepidation

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Hello, inside this pack there is a Samsung battery module in 12s 1p. Samsung Module Tag Does anyone know the original use of this? I also made a quick video of the charger and battery pack that comes with the 4.2 kWH 48v golf cart kit...
It's interesting that the BMS inside is labeled LiFePO4 but the BMS allows 4.2 volts per cell. BMS Label Why would they label this incorrectly? Or is Big Battery programming these generic BMS modules? Thoughts?

Thanks,
A.J.
 
The label shows 3.7V LiFePO4, not typical 3.2V LiFePO4. Did you check the Voltage of each cell?
 
Yeah, it seems like mine might be 12 "NMC/LI-Ion Cells". 12 x 4.2v = 50.4v the recommended charge voltage.
Mine have been running 50.4v for a while. I wonder if a little lower charge voltage would extend the cycle life? Maybe 49V or 4.0833v per cell?
 
The label shows 3.7V LiFePO4, not typical 3.2V LiFePO4. Did you check the Voltage of each cell?
Yes the pack tops out at 50.4 volts or 4.2 volts per cell. You are correct 3.7v would be the correct nominal voltage. I guess the LiFePO4 shouldn't be taken literally.

A.J.
 
Yeah, it seems like mine might be 12 "NMC/LI-Ion Cells". 12 x 4.2v = 50.4v the recommended charge voltage.
Mine have been running 50.4v for a while. I wonder if a little lower charge voltage would extend the cycle life? Maybe 49V or 4.0833v per cell?
I tend to keep my packs at half charge and top off when I plan on using them. It's more about the time the pack sits at full charge as well as the max charge voltage. There is a little adjustable trim pot for the charger voltage you could reduce if you wanted.

A.J.
 
I'm trying to use these for a back-up power source during grid failures. So, staying at a good SOC would be idea.
I've read advice somewhere about not leaving them at full-charge for too long. Also discharging them (by some percentage?) periodically.
So, I'm thinking of setting my solar charger for 49v and use up some Amp hours every weekend (while I'm home).
Since I'm a newbie, I'm not up to speed on Best Practice for getting some BDGRs to last a few years.

My other problem is weather, if it looks like rain all week, I would skip a discharge cycle because I might need power on sump pumps.
And if's going to overcast for 4 or 5 days, I don't want to be too low on AHs. Have to work around the awful MA weather.

Found this today: https://gocarlite.com/product/48v-12ah-lithium-ncm-battery/
"NCM cell has 3.6 +/- 0.5V nominal working voltage and is cut-off at 4.15-4.20V per cell during charging."
I guess NMC are NCM the mostly the same chemistry.
So, if my BDGR pack cells are being floated at 4.2V on every sunny day, would that shorten their life span as a back-up supply?

Cheers,
Rich
 
Last edited:
I'm trying to use these for a back-up power source during grid failures. So, staying at a good SOC would be idea.
I've read advice somewhere about not leaving them at full-charge for too long. Also discharging them (by some percentage?) periodically.
So, I'm thinking of setting my solar charger for 49v and use up some Amp hours every weekend (while I'm home).
Since I'm a newbie, I'm not up to speed on Best Practice for getting some BDGRs to last a few years.

My other problem is weather, if it looks like rain all week, I would skip a discharge cycle because I might need power on sump pumps.
And if's going to overcast for 4 or 5 days, I don't want to be too low on AHs. Have to work around the awful MA weather.

Found this today: https://gocarlite.com/product/48v-12ah-lithium-ncm-battery/
"NCM cell has 3.6 +/- 0.5V nominal working voltage and is cut-off at 4.15-4.20V per cell during charging."
I guess NMC are NCM the mostly the same chemistry.
So, if my BDGR pack cells are being floated at 4.2V on every sunny day, would that shorten their life span as a back-up supply?

Cheers,
Rich
Yes keeping the pack at 4.2 v per cell will shorten the life. But don't worry. Maybe only charge to 4 volts per cell instead. You actually won't loose to much capacity since the discharge curved is very "flat" except at the ends. Maybe run a capacity test and see.

A.J.
 
Yes keeping the pack at 4.2 v per cell will shorten the life. But don't worry. Maybe only charge to 4 volts per cell instead. You actually won't loose to much capacity since the discharge curved is very "flat" except at the ends. Maybe run a capacity test and see.

A.J.

Thanks! They are at 4.0833 right now. The TS-45 is set for 49 volts. I'll take it down to 48v, (4.0) next time I get down there with the laptop.
Since I'm 75 years old, maybe I don't need these batteries to last for a very long time.. :)
 
Thanks! They are at 4.0833 right now. The TS-45 is set for 49 volts. I'll take it down to 48v, (4.0) next time I get down there with the laptop.
Since I'm 75 years old, maybe I don't need these batteries to last for a very long time.. :)
My neighbor is 103 years old, swims daily, and drives still.
 
Hello, inside this pack there is a Samsung battery module in 12s 1p. Samsung Module Tag Does anyone know the original use of this? I also made a quick video of the charger and battery pack that comes with the 4.2 kWH 48v golf cart kit...
It's interesting that the BMS inside is labeled LiFePO4 but the BMS allows 4.2 volts per cell. BMS Label Why would they label this incorrectly? Or is Big Battery programming these generic BMS modules? Thoughts?

Thanks,
A.J.
Hey BlueT, any update on how this battery has performed since your original post?

Any thoughts on the feasibility of a parallel array of 2 or 4 of them?
 
I'm using 3 in parallel and they seemed to be working great.
But recently I've noticed the charge controller has been registering a few Ah were used to charge them up.
Normally, I don't see any charging at all, until I've used the battery bank for a while.
Maybe the large LED displays are using enough to notice after a few days.?.
 
I'm using 3 in parallel and they seemed to be working great.
But recently I've noticed the charge controller has been registering a few Ah were used to charge them up.
Normally, I don't see any charging at all, until I've used the battery bank for a while.
Maybe the large LED displays are using enough to notice after a few days.?.
Awesome, thank you. The installation is fully off-grid, but limited use. Appreciate your insight.
 
One other thing that I'm wondering about is having 3 "smart" BMS boards in parallel.
1. These three units are charged by the Solar charge controller during sunny days, to approx. 49.00V (the Badgers LEDs mostly display 48.9V).
So, all three of these BMS units are still actively open for more input/charging.

2. If the light LED load on one of the Badgers lowers it's voltage to drop down to Less Than 49.00V, (at night)
the other two batteries will start to discharge, and Top-Off the lower voltage Badger.

Is it possible that a lot of BMS nighttime activity is loading down the Bank enough to show up as a few AH of usage?
 
Hello all. I installed these in a golf cart and sold it off to a family member but I'll post back once I get over there and check up on the batteries.
 
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