question

roadman avatar image
roadman asked

75/15 no amps

Ok 2nd try. Shorter version. 100w 18v panel to 75/15 smart with bluetooth to 195ah deep cell. Full sun -at start voltage reading from panel 17.6v all good. To battery from controller 14.4v in bulk mode all good. Problem readout no amps from panel to controller and no amps from controller to battery. Plus despite battery not being full controller goes from bulk to absorbtion to trickle charge mode in about 20 seconds and stays there all while there are still zero amp readings. Everything was properly installed. Changed the fuse. No difference. Any ideas

MPPT Controllers
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2 Answers
Bill avatar image
Bill answered ·

You may not have enough voltage from that panel to start the controller. Check the manual, Vbat + ? Often it needs to be 5 volts more than the battery. The 17 volts you mention may be cutting it too close. (or you reversed your panels polarity.)

-Bill

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roadman avatar image
roadman answered ·

Thanks for the pointers Bill. I will be testing for everything plus reverse polarity as suggested now that I am back from the trip we went on through Zambia and Malawi just after the installation of the mppt - which was a last minute recommendation of a 4x4 workshop when doing final preps. I have only previously used pwms. Had no time to personally test it and trusted it would work. The problems were picked up on the trip when needing solar which resulted in us having to move on early from places without 220v mains and drive around a bit more to ensure substantial fridge stock remained cold/frozen, which was a bit frustrating. Seems like there is actually a bit more to mppt technology when it comes to proper installation, wiring and panel pairing etc. Previous experience with pwms was good. Simple and straight forward and reliable in my personal case. Must say this experience is making me nervous. Cant afford such problems in eg central kalahari in Botswana where you have to be totally self sufficient.

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