Small 12 volt system using an MPPT charge controller

[mjby]

I have a 135 watt Kyocera panel (nominal voltage 17.6, approx 7 amps) to charge a 100 amp hour agm battery system using a cheap 15 amp pwm charge controller. Very small, but it works. In Wisconsin; love these longer days of sunlight!

1) Does one gain much charging ability using a Morningstar SunSaver 15 amp MPPT controller with the Kyocera panel?

2) Would one gain a lot using a larger voltage panel (ie Schott 230 panel- nominal voltage about 27 volts, also about 7 amps) with this small agm battery system and the MPPT charge controller? Both of these panels put out about 7 amps, but would I be able to charge more efficiently using the higher voltage panel kick in with the MPPT?

Newbie in my knowledge but have learned much from of you pros here; thank you!

[XeonPony]

I started off  with two of the same pannel and a sunsaver 15 mppt with the batery temp sensor and it was a massive improvment mainly I wired the pannels in series.

Worked great now I run 4 pannels with a tristarmppt 60.

So I say go for it!  FYI The temp sensore is a simple 10K NTC thermister you can make one easily!

[mjby]

Thanks for the reply!

Into a 12 volt battery, if one has a 27 volt panel  putting out the same amps as a 17 volt panel, do you start charging quicker with the larger volt panel using a MPPT charge controller and thus get more juice into your 12 volt battery?

[DamonHD]

Do you mean the same amps (and thus more power at the higher voltage) or the same power?

A decent MPPT should be getting energy into your battery in that situation as soon as any is available (since Voc of either panel will be above Vbatt if there's any sensible light around, even if Isc and Wmpp might still be very low), so I'd have thought that there'd be little difference.

But theory and practice are not the same, in practice...

Rgds

Damon

[XeonPony]

In practice I noticed vast improvement once I wired them in series, cloudy weather I was geting marked improvment in intake and my early morning and dusk intake levels where better as well during noon it would go into current regulation mode at 200w steady.

but I was opperating at 40+ voc and 30 to 33 Vmp (Still am only with more pannel larger controler)

I started out with crap pannels and the MppT was worth it's wait in gold with them and when I got the Kyoshera pannels even better!

[mjby]

Thanks for the help on this question. It is appreciated. MJBY