- #1
PhysicoRaj
Gold Member
- 538
- 49
Hi everyone,
I wanted to make a powerbank for myself, to be able to charge smartphones (and if possible laptops), and last for as long as possible.
The reason I'm attached to Ni-MH batteries is because of this eneloop IV gen, claiming such attractive values for charge retention (70% after 5 years), maximum cycles (2100) and is relatively affordable.
Because longlife is my main aim as I stated.
Load requirements:
Pmax = 128W
and if this figure looks crazy, omit the laptop charge, Pmin = 48W.
The input for charging the bank would be a micro USB female, I actually am not concerned very much about charging time. I want to be able to deliver 48W from a pack of eneloop cells. Each cell is 2000mAh, 1.2V and discharge current? Um, not very clear, seems like they'll give 2C easily but I need some help in deciding discharge current.
I know that unlike Li-ion cells, charging Ni-MH is challenging, and I'm not finding good Ni-MH charging modules easily. Lastly, the series-parallel configuration for the battery pack, I'm scratching my head. Each cell is 1.2v, but connecting them in series to increase voltage would make charging them difficult (as I'm aware Ni-MH require individual cell monitoring if charging in a pack), so connecting every cell in parallel seems to be the option, then boost 1.2v to required voltage for those USB supply controller boards.
48W at 1.2V would mean 40 amps. If each cell can discharge at 2C (4A) then 10 such cells in parallel could make the pack.
Correct me anywhere if I'm wrong and your advice would be of great help!
Thanks.
I wanted to make a powerbank for myself, to be able to charge smartphones (and if possible laptops), and last for as long as possible.
The reason I'm attached to Ni-MH batteries is because of this eneloop IV gen, claiming such attractive values for charge retention (70% after 5 years), maximum cycles (2100) and is relatively affordable.
Because longlife is my main aim as I stated.
Load requirements:
- I wish to have two USB Type-C outputs, each has to deliver a maximum of 4A at 5V (I don't actually plan to plug superfast charging devices, I would use recommended chargers for them).
- One USB Type-A output, 1.5A (DCP)
- And if feasible, a 20V 4A DC output for laptops.
Pmax = 128W
and if this figure looks crazy, omit the laptop charge, Pmin = 48W.
The input for charging the bank would be a micro USB female, I actually am not concerned very much about charging time. I want to be able to deliver 48W from a pack of eneloop cells. Each cell is 2000mAh, 1.2V and discharge current? Um, not very clear, seems like they'll give 2C easily but I need some help in deciding discharge current.
I know that unlike Li-ion cells, charging Ni-MH is challenging, and I'm not finding good Ni-MH charging modules easily. Lastly, the series-parallel configuration for the battery pack, I'm scratching my head. Each cell is 1.2v, but connecting them in series to increase voltage would make charging them difficult (as I'm aware Ni-MH require individual cell monitoring if charging in a pack), so connecting every cell in parallel seems to be the option, then boost 1.2v to required voltage for those USB supply controller boards.
48W at 1.2V would mean 40 amps. If each cell can discharge at 2C (4A) then 10 such cells in parallel could make the pack.
Correct me anywhere if I'm wrong and your advice would be of great help!
Thanks.
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