Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Charging batteries from the grid
#1
I'm working on a diy 12S powerwall that will be both charged by the grid and discharged into the grid.

System would have a max voltage of 12 * 4.2 = 50.4V
But I will be limiting it to 4.0v per cell (48V) for extra cycle life.
(System will have a hard life, it will cycle once per day in the summer and twice per day in the winter)

I can easily come up with a cheap, high power, high efficiency 48v PSU.
But the only circuit I know of to limit current would be a simple linear regulator,
And that would kill my efficiency.


Could I use a PWM solar charge controller limit the current into the battery from a 48v dc psu?
What are some other frugal options?

EDIT:
Reading some more about what pwm charge controllers actually do, I don't think my first idea would work.

"PWM Controllers - When charging, these controllers feed the power from the panel straight through to the battery until
the battery voltage reaches a predetermined Acceptance level. It will then keep the voltage at that level by pulsing
the panel voltage on and off to keep the battery voltage constant."
Reply
#2
Use a 24/36V PSU and a boost converter.

PWM will not work because they work like a slow manual switch (on/off) at times.

Most efficient option, buy a used HE flatpack2 unit but you would need to change the output voltage with a separate computer controlling the flatpack.
If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
Reply
#3
12s is not 48v and you Will have issues finding Gear supporting it. Use 14s. Secondly is it legal where you live?

Easiest is just a PSU straight into the battery via the bms. Just det the psus voltage to the battery.
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 100kWh LiFePo4 | 20kWh 14s 18650 |  66*260W Poly | ABB S3 and S5 Trip breakers
Upcoming: 14S 18650~30kWh
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)