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APPENDIX 2- b)
b) Battery
Iu × Autonomy (days)
Depth of discharge×Inverter efficiency
Battery capacity (Ah) =
=
11.58 (Ah)×3(days)
0.7×1.0
= 49.63 (Ah)
You must choose Deep cycle battery that capacity is more than 49.63 Ah.
c) Charge controller
Capacity of a charge controller must be more than Isc.
And in the case of a DC system, Capacity of a charge controller must be more than load current.
Maximum (starting) current varies on a kind of appliance, and there are generally as follows.
Lights : rated current × 1 ~ 2
TV
: rated current × 2.5 ~ 5
Motor : rated current × 5 ~ 10
In this case, load current are follows.
appliance
Light
Rated current (A)
0.67
Maximum current (A)
0.67×2= 1.34
W&B TV
2.5
2.5 ×5=12.5
Radio
1.25
1.25×2= 2.5
Maximum load current (A) = Lights rated current + TV maximum current + Radio rated
current
= ( 0.67×2Qty ) + 12.5 + 1.25
= 15.09 (A)
＞
3.38 (A):Isc
You must choose Charge controller that capacity is more than 15.09A.
If possible, capacity had better increase 20% for safety factor,
In this case, Charge controller capacity is more than 18.11A is better.
Code of Practice for Off-grid Photovoltaic Systems
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