Need a recommendation for a friend: 400w all in one "plug and play" solar system

Re: Need a recommendation for a friend: 400w all in one "plug and play" solar system

What do you mean by "400 Watt" system... Is that the inverter output, the solar array size, or what...

Any information on what the loads would be? (i.e., 400 Watts * 5 hours per night = 2,000 WH per night--Or what)?

Rough location (amount of sun)? Summer/Winter usage? Backup Genset?

Personally, I would suggest designing a 1,000 WH per day system @ 12 volts with a MorningStar 300 Watt TSW inverter setup with remote on/off switch and/or "search mode".

• 1,000 wH per day * 2 days of storage * 1/0.50 max battery discharge * 1/12 volt battery bank * 1/0.85 AC inverter eff = 392 AH @ 12 volt battery bank (4x 6 volt ~200 AH golf cart batteries)

Battery bank based on 5% to 13% rate of charge:

• 400 AH * 12 volt battery bank * 1/0.77 panel+controller derating * 0.05 rate of charge = 312 Watt minimum array
• 400 AH * 12 volt battery bank * 1/0.77 panel+controller derating * 0.10 rate of charge = 623 Watt array nominal
• 400 AH * 12 volt battery bank * 1/0.77 panel+controller derating * 0.13 rate of charge = 810 Watt "cost effective maximum" array

Then there is recharging the 1,000 WH per day via sun. Using PV Watts for Lansing MI, array 43 degrees from horizontal, fixed mount:

Month    Solar Radiation (kWh/m 2/day)
1      2.65     
2      3.60     
3      4.42     
4      4.95     
5      5.38     
6      5.57     
7      5.88     
8      5.45     
9      4.98     
10      4.01     
11      2.60     
12      1.97     
Year      4.29

Toss the bottom 3 months, gives you 3.6 hours of sun for February (use generator for dark days in 3 months of winter, as needed):

• 1,000 WH per day * 1/0.52 AC system eff * 1/3.6 hours of sun = 534 Watt array minimum

So, this would be around 534 to 810 Watt array--And I would suggest 623 to 810 Watt array (10 to 13% rate of charge) for daily 9+ month a year residency. The smaller 5% rate of charge would be weekend/seasonal cabin. If occupied in winter, perhaps panels that can tilt to vertical is there is deep winter snows (self cleaning).

Generator--Basically a 10% rate of charge on a 12 volt @ 400 Amp battery bank would be ~40 Amp battery charger.

And Iota 45 amp 12 volt charger on a Honda eu2000i or equivalent Yamaha inverter-generator. They are quiet, reasonably efficient, and pretty reliable.

Iota DLS-45 12 Volt 45 Amp Regulated Battery Charger

Some support gear:

• Add a Hydrovolt hydrometer (very nice).
• An AC/DC Current Clamp meter.
• Kill-a-Watt type meter
• Battery Monitor (or Victron brand) (very nice, but expensive for smaller systems)
• add circuit breakers for inverter/solar charge controller/AC battery charger
• For the smaller arrays, you could use a 30 amp MPPT charge controller... For the larger arrays, you would want around a 45 Amp minimum MPPT controller (PWM controller + "12 volt" solar panels are a possibility too--Depending on price/shipping costs/etc. of 17.5 Vmp vs ~30 Vmp panels and PWM vs MPPT controllers).

What would a 400 AH @ 12 volt power supply running a 120 VAC inverter be capable of? (very rough guidelines for deep cycle flooded cell batteries):

• 400 AH * 12 volts * 0.85 inverter eff * C/20 discharge rate = 204 Watts average (5 hours per night, two nights of "no sun")
• 400 AH * 12 volts * 0.85 inverter eff * C/8 discharge rate = 510 Watt average max continuous discharge rate
• 400 AH * 12 volts * 0.85 inverter eff * C/5 discharge rate = 816 Watt max short term continuous discharge (hour or so)
• 400 AH * 12 volts * 0.85 inverter eff * C/2.5 discharge rate = 1,632 Watt starting surge (few minutes to start a well pump, etc.).

Its a start... If full size energy star refrigerator and 9+ month occupation, then look at a ~3.3 kWH per day system with 24 or 48 volt battery bank, and ~1,200 to 1,500 Watt inverter minimum (TSW recommended).

-Bill

Re: Need a recommendation for a friend: 400w all in one "plug and play" solar system

Steven Lake wrote: »

Well, the 400w (panel size, not inverter) was the base system I figured he'd need. .... Hence my figuring that a plug and play system with 400w of panels would be a good place to start. After all, if all you're powering is the coffee pot, a fridge and a few electronics, you're pretty much not gonna need more than that. As for inverter power, eh, 1500w-3000w would be plenty. Battery capacity I have no idea honestly. I've looked at something like this as a recommendation, but it's a bit too pricy and has somewhat "meh" level reviews. Plus it only has 80w of panels and 55ah of battery, which is way too small IMHO. But anyhow, that's the kind of all in one system I'm thinking of.

Really depends... If coffee pot+120 VAC full size fridge+stuff (does stuff include a well pump/cabin pressure pump?)--You are looking at close to a 2-3.3 kWH per day system.

The above system that I suggested--Use a propane powered fridge (especially if weekends/seasonal). And a 1.5kW MSW inverter to power the coffee pot+some hand tools (without needing to fire up the genset). Still keep the 300 watt TSW inverter for small stuff (electronics, battery/cell/computer chargers, LED lighting, etc.).

Or get a propane "Mr. Coffee" and a vacuum thermos to keep it hot.

-Bill

Re: Need a recommendation for a friend: 400w all in one "plug and play" solar system

You could invite him to the forum here...

One of the neat things about starting from scratch and helping him to design the system--Later on they will be able to monitor, understand, and do maintenance on their own system.

Even something as simple as a one or two panel system takes a lot of learning when starting at ground zero:

BB. wrote: »

Add this link to our Solar Beginner Post:

Emergency Power

Basically a very long thread that starts from the beginning with a few vague requirements through design and assembly for a "portable" solar RE off-grid power box.

And here is another example by Mike90045 called the Solar Monolith:





Update pictures/information here.

-Bill

-Bill

Re: Need a recommendation for a friend: 400w all in one "plug and play" solar system

If you go with the Amazon "system"... I would get him the MorningStar 300 Watt 12 volt TSW inverter (~$240) setup with "search mode", or at least, the external on/off switch.

A 1,000 Watt inverter on a 400 watt solar array--Not sure it is at all practical.

400 Watts * 1/14.5 volts charging * 0.77 panel+controller losses * 1/0.10 rate of charge = 212 AH @ 12 volt battery bank

And a pair of 6 volt golf cart batteries (around 215 AH)... As close to a reliable, useful, low maintenance system as you can get.

Also, give him a Sears AC/DC Current Clamp DMM for him to play with. A Kill-a-Watt type meter would be nice too.

Obviously, a pair of ~240 Watt GT type panels: ~2x$245
A Midnite Kid controller: ~$285
MidNite Solar Whiz Bang Jr Current Sense Module: $45

Choices....

-Bill

Re: Need a recommendation for a friend: 400w all in one "plug and play" solar system

Thank you Eric:

Shunt:

http://www.solar-electric.com/midnite-solar-shunt.html

$34

-Bill