Irfan Latif
New Member
I have a 12V, 200Ah deep-cycle lead-acid tubular battery which I charge with solar panels.
PV array specs are:
To have a longer battery life, I want to charge the battery at maximum 20A (@10 hours) in the first bulk charging constant-current (CC) stage. There's no setting in the charge controller to set the maximum charging current. During the peak sun hours, I get up to 35A current. If a load of 200W or more (@12V) is connected, the battery charging current remains within limit. But if there's no load, battery may get charged at higher rate.
So I was thinking about making a variable current limiter device. A current sensor (e.g. an ACS758) will sense the current at the battery terminal and feed it to a microcontroller (e.g. an Arduino Nano) which should then limit the current by a calculated amount if the battery is receiving more than 20A. Is it possible using a MOSFET, or a digital potentiometer, or by creating a dummy load?
Note that the required power dissipation may go up to 21V x 15A = 315W (if done on PV side of the charge controller) or 12V x 15A = 180W (if done on battery side). But it depends on the time of day and the connected load; so requires a variable current limiter.
PV array specs are:
Code:
Max Power 840W
Voltage at Max power 23.70V
Current at Max power 35.46A
Open-Circuit Voltage 24.22V
Short-Circuit Current 41.90A
To have a longer battery life, I want to charge the battery at maximum 20A (@10 hours) in the first bulk charging constant-current (CC) stage. There's no setting in the charge controller to set the maximum charging current. During the peak sun hours, I get up to 35A current. If a load of 200W or more (@12V) is connected, the battery charging current remains within limit. But if there's no load, battery may get charged at higher rate.
So I was thinking about making a variable current limiter device. A current sensor (e.g. an ACS758) will sense the current at the battery terminal and feed it to a microcontroller (e.g. an Arduino Nano) which should then limit the current by a calculated amount if the battery is receiving more than 20A. Is it possible using a MOSFET, or a digital potentiometer, or by creating a dummy load?
Note that the required power dissipation may go up to 21V x 15A = 315W (if done on PV side of the charge controller) or 12V x 15A = 180W (if done on battery side). But it depends on the time of day and the connected load; so requires a variable current limiter.