Quote:
Originally Posted by boywonder
If you have a large residential house type panel (these are usually 250-300W each) then you need to run an MPPT type controller; you can't run a typical PWM cheap RV controller since these are around 37V open circuit.
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I have been fooled by some of these cheap Chinese PWM controllers. The claim was they accepted more than the typical 12V range but now I see they are clarifying that that is only for 24V battery systems.
For example:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Quote:
A: To charge a 12V battery, the working voltage of the solar panel can be between 17V and 23V, and for a 24V battery, the working voltage of the solar panel can be between 36V and 46V.
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Even if the PWM controller will accept the higher voltage (I think it is a power limitation more than a voltage limitation) then you will significantly limit your power output of the residential panel.
PWM does not boost the current. So if your 350W panel puts out 9 amps, that is all the charging amps you can get out of the PWM charger or 9A*12V=108W nominal. In other words about 1/3 of the max.
This is what I measured in full sun light anyway.