Adding different make panels?

arby

Hello, I have found out that my system is too low on panels. 4 x 130 watt Kyoceras in series into MX60 controller and 8x6 volt in series Surette S 530 batteries. An Xantrex SW 5548 inverter. I have purchased 4 X 270 watt /24 volt Suntech panels. My plan is to wire the Suntechs into 2 strings of 48 volts each and then run all 3 /48 volt strings into a 3/15 amp breaker combiner box and send the result the 50 meters to the controller. Sounds reasonable to me, but is there something I am missing in my thinking?
Thanks, Russell

Cariboocoot

Re: Adding different make panels?

You really are under-paneled!

The Kyocera's Vmp is 17.7. Put four in series you get 70.8
The Suntech's Vmp is 35. Put two in series you get 70

That is close enough for paralleling the strings in my book. What's more, the current ratings are very close as well (7.63 and 7.71). The 15 Amp breakers should work fine for string-to-string protection.

You will have 1620 Watts of panel, out of which you could reasonably expect a peak charge current of about 26 Amps. Unfortunately the S530 is a 400 Amp hour battery, so your charge rate will be about 6.5%, which is still a tad low especially with loads on at the same time.

It will be a lot better than just the Kyocera's alone, though.

arby

Re: Adding different make panels?

Thank you. I know that it is cutting close but this is a remote cabin and the use is fairly minimal.

arby

Re: Adding different make panels?

And I forgot to mention that the system is connected to a 5500 watt Honda generator with auto start with both sides wired to put out 120 volts if needed.
Another question. The trimetric never seems to show more than 49.4 or 49.5 volts even though the MX 60 shows much higher for the battery bank. I have put a voltmeter across the battery posts and it always agrees with the MX60.

Cariboocoot

Re: Adding different make panels?

This will sound like the bleeding obvious but ... are you sure you have the Trimetric wired right? One of the easiest mistakes to make is to put the controller on the wrong side of the shunt.

arby

Re: Adding different make panels?

I'll check that this weekend. Thanks.

Cariboocoot

Re: Adding different make panels?

Just in case:

The SIG connection on the Trimetric goes to the battery side of the shunt. G1 and G2 go to the load/charge side.

And this warning from the manual: "If the single wire connecting from the meter + and M+ terminals to the battery is over 1 ohm, the "volts" will read slightly less than true."