Upgrading present system....

Re: Upgrading present system....

Thank you BMET & Niel for your input, and math. I have seriously considered installing one more 85 watt Kyocera, to make it a even 6 panels=28.96 amps. I have considered a 24 volt battery configuration, but my battery compartment space is limited to 3 batts, of the 12 volt version & physical size restrictions. However, I could proably extend into one of the lower compartments. It would require a lot of cutting out end panels of the compartment, and a reconfiguration. As stated earlier, I do have the room for a couple more panels, mabey three, and earlier I considered a Kyocera 135 or 140 watt panel. Then they (physical size) would fall into the shading catagory. So that was out. So far there's not a flicker of shade on any of the panels. It's a situation of darned if you do, and double darned if you don't.

The reason that I decided to go with a PWM, instead of the MPPT; is as follows. First I have noticed a increase in current during the month of Dec. and early Jan. After that nothing. The second reason is that I started with the SB2000. It was sent in to, at the time RV Power Products two different times. Why? Both times it would show the proper current when immediately connected...then go nuts, showing anywhere from +95 amps to -2.5, as fast as it could move the digits. The voltage reading always seemed to be correct. At first I deemed it was static electricity from me, so I started using the eraser end of a pencil....same results while moving the switch through all three settings of array current, output charge current, and voltage readings. The only thing that ever held proper was the voltage reading. Then I went with the 2000E, it performed properly, however it revealed the same senario in mid Dec to early Jan. with somewhere in the neighborhood of 5 to 7% diff. This happened three or four times, and never again.

Then I decided to go with a larger array. Well, as someone stated on this forum that the 2000E was not a true 25 amp controller as advertised, (I believe it was Crewzer) and that it was actually a 20 amp controller. I made a decision based on that, and decided to go with the MS 45 amp PWM controller, simply based on the gains, not much, that I had experienced just in Dec., and Jan. However, by then I was exceeding the capacity of the controller, and not getting the advertised buck's worth. Neither in amps or performance.

The inverter; yes that was a mistake by going too big. Live and learn I guess, and the learning curve hasn't been cheap. The inverter hasn't been used more that three times, and probably never will be again. I use the charger at times when it's overcast, or in the winter when it's cooler here, but it'll never get the chance to invert again. I will go with the 300 watt MS, probably two, as soon as I get caught up on the required meters and other related componets. Question is; would it be wise to install a separate shunt for each meter, or use just one shunt? The MPPT controller.....I don't think in my situation of panel array, and extreme heat for 6 to 7 months of the year in my location warrants the extra expense for two or three days of additional current during a given year. At least that's all I've seen from the last two MPPT's.

Re: Upgrading present system....

niel wrote: »

i would not give up on mppt even if you opt for a pwm cc now. to be honest the sb2000 didn't impress me and i do own an sb50, but i threw the thing out of whack on its adjustment. there are some good mppt controllers around now and more to come. the blue sky stuff is old technology.

Thanks Niel, and all the other guys for their input. I haven't given up on the MPPT.....yet! I already have one in storage, and another coming up soon, that being the Blue Sky 2000e.

Westbranch: "Something is bugging me about your comment that you had 2 CCs that BOTH performed erratically ... very strange ??? wiring or ??
With the various panels I would look at an MPPT again, say Rogue? and a small inverter as you state."

What happened is the first controller, a RV Products SB2000....the name was changed to Blue Sky a few years ago....was that I had sent it to them for repair, (under warranty) twice, had all wiring checked on my end, but once reinstalled it still gave nutty readings on the PV current in, and output charge current, sometimes it read +95 amps, and other times it read -2.5, 3.5, and more....whatever it felt like at the given time. The second controller was a Blue Sky 2000e. However, I feared of blowing the controller due to the fact that the charger amperage was advertised as a 25 amper meter, but was rated much lower, as I discovered later. With that in mind....trust only goes so far!! Yes, I did consider the Rogue. As a matter of fact it was the number one on the thinking list until I discovered that I was pushing the limit on the Isc side. Mark explains it very well in the manual. As it stands presently...I have 4@ Kyocrera 80 watters, 1@ Kyocera 85 watter,(they say 87) but that remains to be seen, and another 85 watter of the same on the way. Making a total of 6 panels. The ratings as follow are Isc ratings. The 4 Kyocera's are rated at 4.97 Isc each=19.88 Isc. The the 85 watter is rated at 5.34 Isc. Those alone are 25.22 Isc....it has already exceeded the NEC, and Mark's recommendations. The one on the way will definiately break the bank at 30.56 Isc. This forum and the intellict of various members brought that to light.....otherwise I wouldn't have given Isc a first thought, not to mention the NEC.