diy solar

diy solar

Design AC coupled Inverter charger Powerwall

KiwiOmar

New Member
Joined
Sep 2, 2021
Messages
2
Location
Auckland, NZ
  1. Looking to build a battery bank LiFeO4 (Lithium Iron oxide) 3.2V 320Ah =1,024Wh x 14 cells = 14,336Wh connected in series or parallel based on using the minimum BMS's for this combination - open to best arrangement of batteries please.
  2. Looking for specifications for an Inverter charger for the above battery to be connected in an AC coupled system?
  3. The idea is to have the battery bank to supply the night-time AC power requirements while the solar power charges the batteries during the day while we are at work.
  4. The monthly peak usage as per electricity bill was 450KWh/30days = 15KWh capacity. Hence average 14KWh capacity.
  5. Wondering if the existing solar 2.5KW grid tie (250W (49V, 5A) ten solar panels) home system will be sufficient to charge the batteries?
  6. Appreciate any help on a reliable Ali express supplier contact for A grade 320/420Ah LiFeO4 battery, BMS's, Fuse types, and Inverter charger?

Thank you in advance, appreciate your support to make this DIY AC coupled Powerwall build a reality.
 
Solar: It totally depends on your location and the avaibility of the sun.
You can find information online about your location and calculate the available power from there. Keep in mind, especially in the winter, solar power is very limited.

As for capacity: With 15kWh daily usage, 14kWh batteries is not likely to be able to be fully independent. LFP generally is recommended to 'only' pull 80% of it's capacity (don't discharge below 20%).

For the solar: 250Wp panels, assuming they are regular house panels, are likely to be older models. somewhere about 10 year or so. I think you're not getting the full capacity anymore, so I think it's safe to assume 200-220Wp max for each panel.
 
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