Best Solar Charge Controller? And Series vs Parallel Wiring

[E350]

Thanks guys!

RallyPanAm: The price is certainly reasonable. Especially with the great review/award! Did you get either of the accessories?

Questions: You wired parallel? Also, with your 300 watts, how come you didn't go MPPT? I am not saying you should have. I am only inquiring, why? Maybe PWM is better for our wattage? And MPPT is for bigger wattage? I really dunno. I am at 320 watts now and will be at an even 400 watts with one more panel.

http://www.blueskyenergyinc.com/product ... charge_30/

"Sun Charger 30

A precise PWM solar charge controller 12V/30 amp entry level quality solar controller. Available with LVD and Lighting control signal
Winner of RV West Magazine Readers Choice Award 2013"

Edit: Check it out! "Maximum recommended PV power – 450W"

[rallypanam]

Originally Posted by E350

Thanks guys!

RallyPanAm: The price is certainly reasonable. Especially with the great review/award! Did you get either of the accessories?

Questions: You wired parallel? Also, with your 300 watts, how come you didn't go MPPT? I am not saying you should have. I am only inquiring, why? Maybe PWM is better for our wattage? And MPPT is for bigger wattage? I really dunno. I am at 320 watts now and will be at an even 400 watts with one more panel.

http://www.blueskyenergyinc.com/product ... charge_30/

"Sun Charger 30

A precise PWM solar charge controller 12V/30 amp entry level quality solar controller. Available with LVD and Lighting control signal
Winner of RV West Magazine Readers Choice Award 2013"

I'll see if I can dig up the emails at home.. but basically, Blue Sky said there was no real benefit for me to get the significantly more expensive MPPT. I was pretty much willing to go MPPT based on everything I read, but when a manufacturer suggests I go a much cheaper route and not spend so much money with them, I listen.

[E350]

Yup, I am listening to you too. When I bought the Xantrex Solar Charge controller, MPPT had just recently come out and it was all the rage, so I had to have it, and spent big bucks and really wasn't that impressed, at least with my system.

[rallypanam]

Maybe I should answer all your questions..

Originally Posted by E350

Did you get either of the accessories?

No. Just temp sensor, which may come with the controller, I don't remember.

Originally Posted by E350

You wired parallel?

Yes, just bought plug and play solar MC4 connectors from ebay.

[E350]

I just emailed an inquiry off to Blue Sky. I will post my inquiry along with their response when I receive it. Thank you all.

[rallypanam]

I just dug through my old email (oh yeah, it's in the cloud!).. I found the initial response to my email from Blue Sky (Rick Cullen) but not any of our further emails. Oh well, you're on the right track!

[Ford_6L_E350]

I've had both a PWM and MPPT controller on my rig with a single 125W panel. Generally, both give similar results, except in marginal conditions the MPPT had more output. Never ran my house batteries down with either one.

Mike

[E350]

Well here's the very helpful email chain for any of you who have similar systems/uses/concerns:

"Dear Blue Sky:

You are recommended highly on the sportsmobileforum.com

I have four BP 380J pv panels fixed on the roof of my SportsMobile. (As soon as I can find another BP 380J, will install the 5th panel, bringing my combined wattage to 400 watts and my combined amperage to 22.5 amps.

The electrical characteristics of each BP 380J panel are:

Maximum power (Pmax) 80W
Voltage at Pmax (Vmp) 17.6V
Current at Pmax (Imp) 4.5A
Warranted minimum Pmax 76W
Short-circuit current (Isc) 4.8A
Open-circuit voltage (Voc) 22.1V
Solar Cells 36 cells (125mm x 125mm) in a 4x9 matrix connected in series

I have a single 250 AH Universal AGM house battery.

My main current draws are:

1. an Engel refrig/freezer, figure 3.5 to 4 amps 100% duty cycle (because it is warm inside in the Summer and warm inside in the Winter with the Webasto furnace and I don't care what they say, if you want to keep things frozen you gotta rotate the dial to "5" which is the 100% duty cycle.)

2. a Webasto diesel furnace for heat in the Winter which uses 4 amps when the furnace fan is cycling on.

My uses are:

A. In the Kirkwood Mountain Resort ski area (7800' elevation, near Tahoe, CA) parking lot or nearby where my wife and I sleep on the weekends and ski 40+ days a year where temps can get down to minus 17F at night and there can be some shading, but strategic parking can avoid shading.

B. At Sherman Island (Sacramento County, CA ) in the Summer where we are beginner windsurfers/beginner kiters where temps can get to 100F.

Question: What Blue Sky solar charge controller should I get?

And should I wire parallel or in series?"

And here's their response:

"Wire in parallel and use the SB3000i."

When I replied asking how the SB3000i compares with the Sun Charger 30 for my system/uses they said:

"That would work too if you don't want to go with an MPPT controller."

Hmmm...

The Blue Sky "Solar Power for your RV" which is one of the FAQ sheets recommend by Scalf77 says this about the SB3000i which if true and if I am reading it correctly could apply to both my cold weather Winter camping and my also my 100F Sacto. valley Summer camping?:

http://www.blueskyenergyinc.com/uploads ... 0-2013.pdf

"- MPPT system operates the PV’s at VMP harvesting more power
and delivering this extra power as increased charge current
– MPPT control system continuously
tracks VMP as VMP & operating
conditions change
– Typical current increase 10 – 20%
- VMP & available power increase as
PV temperature decreases
- May exceed 30% in freezing
temperatures & discharged battery
- May go to 0% in hot climates"

My underline. So as far as Blue Sky goes, it seems that it is either SB3000i MPPT or Sun Charger 30 PWM.

Am I reading the sheet correctly that "current" i.e., amps fluctuate with temperature? I.e., does that mean that amps can increase 30% in freezing temps with discharged battery and amps can go down to "0" on some of my 100F+ Sacto. valley days?

And if so, wouldn't that mean that with an MPPT controller you would want to wire parallel so as to maximize amps? (I.e., isn't parallel wiring additive to amps?)*

Does that mean that volts do not flutuate with temperature? (Isn't series wiring additive to volts?)

Any other real world suggestions?

*Scalff77: If so, I can see where my series wiring job could have handycapped my previous Xantrex MPPT solar charge controller...

[rallypanam]

Not super helpful. I'd ask for more info! Maybe he's just having a bad day!

[E350]

RallyPanAm: Your Richard Cullen wrote the sheet. Alex was my email contact. Probably just the luck of my draw...