I'm looking at a compact setup for island camping with a 52V 20ah (14S7P) EM3EV battery I have to charge a 40litre fridge from solar.
My question is will the following setup work? and are my calculations right?
CALCULATIONS
Battery - 52V x 20.7 ah = 1040wh (use 1000wh) (8A max charge current @ 240V, max continuous discharge 40A (HG2 cells))
Brassmonkey 40litre fridge load (running on 12V, real world stats)
uses 3.5A @12V set at 1 degrees, uses 19ah over 7 hours (2.71ah per hr = 65ah per day)
65ah x 12V = 780wh
780wh x 1.2 = 936wh (add 20% for loss from DC conversion and solar charging)
Therefore battery will need a full charge from solar each day to keep the fridge cold
1000wh/150w panel = 6.7hrs of sun required
1000wh/200w panel = 5 hrs of sun required
COMPONENTS
battery $0
$62 400W MPPT solar controller, 18-55V input, 24-85V output
https://www.aliexpress.com/item/100...&terminal_id=5de8a0b6a4764af58aefc2520dabdefc
$39 DCDC converter from 15-60V of battery to 12V 26A 312W supply for fridge
https://www.aliexpress.com/item/400...&terminal_id=5de8a0b6a4764af58aefc2520dabdefc
OR
$62 DCDC converter from 40-90V input to 12V 20A 240W output
https://www.aliexpress.com/item/328...&terminal_id=5de8a0b6a4764af58aefc2520dabdefc
If anyone has tried buck/boost conversion for this purpose i would be keen to know if it works.
Cheers!
My question is will the following setup work? and are my calculations right?
CALCULATIONS
Battery - 52V x 20.7 ah = 1040wh (use 1000wh) (8A max charge current @ 240V, max continuous discharge 40A (HG2 cells))
Brassmonkey 40litre fridge load (running on 12V, real world stats)
uses 3.5A @12V set at 1 degrees, uses 19ah over 7 hours (2.71ah per hr = 65ah per day)
65ah x 12V = 780wh
780wh x 1.2 = 936wh (add 20% for loss from DC conversion and solar charging)
Therefore battery will need a full charge from solar each day to keep the fridge cold
1000wh/150w panel = 6.7hrs of sun required
1000wh/200w panel = 5 hrs of sun required
COMPONENTS
battery $0
$62 400W MPPT solar controller, 18-55V input, 24-85V output
https://www.aliexpress.com/item/100...&terminal_id=5de8a0b6a4764af58aefc2520dabdefc
$39 DCDC converter from 15-60V of battery to 12V 26A 312W supply for fridge
https://www.aliexpress.com/item/400...&terminal_id=5de8a0b6a4764af58aefc2520dabdefc
OR
$62 DCDC converter from 40-90V input to 12V 20A 240W output
https://www.aliexpress.com/item/328...&terminal_id=5de8a0b6a4764af58aefc2520dabdefc
If anyone has tried buck/boost conversion for this purpose i would be keen to know if it works.
Cheers!