Was pricing our options for a client who'd requested off grid power for their rural sawmill. They needed enough power to run a small beer fridge and for smart phones and a very efficient little notebook. They have generators for running real equipment, and the saws use internal combustion engines.
I had a small fridge lying about (actually have another 4 or so). Pick them up at estate sales and such for five to twenty bucks. Used a kWh measuring device (KillaWatt Brand) and ran it for a week, determining that it was consuming about 300 wH per day. So I figured a 100 W panel ought to be sufficient given that they have good sun resource on any day warm enough to need beer.
Note that I did not calculate in the fact that they'd be putting extra stress on the fridge by putting warm six packs in it every day or so. Could have done this by factoring in the specific heat of water (how much energy it takes to raise a given mass of water a given degree) and then working backwards and assuming an inefficiency coefficient based on the efficiency of refrigeration processes. If I had done so and used an egregiously inefficient coeficient, say 1 Wh of cooling (i.e., BTU converted to watt hours) requiring 1 Wh of energy to run the fridge, I'd get about 80 Wh of energy consumption to cool a gallon of beer, or about 50 Wh for a 6 pack. Frankly, I should have included this in the estimation, but assumed it wouldn't be that big a deal. Note that a 1 to 1 ratio is fairly inefficient, so there's a lot of wiggle room here. So, bottom line is that even if they switch out a 6 pack a day, total consumption ought not to exceed about 350 - 400 Wh per day. The roof pitch and sun resource here (southern Oregon) is pretty good. I figured they'd get at least 600 Wh ,delivered, with this panel in this location, in the summer.
Bottom line is that the panel seems to be providing enough energy, but we are going to need to add an additional 1200 wH battery since the depth of discharge gets too high if we get any morning fog. Even without that, 400 Wh is about a 33% DoD. That's not bad, but given the occasional morning fog issue, the battery takes some stress on occasion. For our application, and the price of an extra panel, it might not be a bad idea to add another panel as well. They don't drink a lot of beer in the winter, but it might not hurt.
As for the system, it was very easy to install and came with mounting brackets and sufficient cable to do it all out of the box.
The only problem was that the client initially used an old deep cycle battery, and on occasion the inverter was shutting down due to low voltage since it wasn't capable of storing 1200 Wh. I ran a new battery over and they installed it. I THINK but can't be sure, that they reversed the polarity or shorted the Charge Controller output leads. When I got there, the Charge Controller was not putting out any current. I had a small Victron MPPT unit in the truck so I just subbed it out. I haven't thoroughly investigated the dead unit yet, but noticed it's got two soldered in fuses(!) I will hook it up and jump the fuses one at a time to see if that's what happened (yes, shame on me, I should have put some fast blowing fuses in the wiring - will get back there in the next week or two to do that). Anyway, the client is happy and I can still go in there to buy lumber without a problem.
Amazon has sent me a replacement Charge Controller, no questions asked, so that is good. I bought the Assurion Warranty on it.
I do want to add that the Victron is overkill for this app so I am going to sub it out with the replacement. The reason is that one of the nicest things about this kit is that the charge controller, while only a PWM, IS rated for 30 amps. So it's easily expandable. (Upto 4 panels I believe.) That's a nice feature, and the Vicron can handle higher voltage, so it's wasted on this application.
All in all I highly recommend this kit for small or introductory set ups. Perfect for small dedicated stand alone applications such as a Flojet Water Pump to slowly pump water up a hill to a cistern for gravity flow to an application, or small fridge. Just don't forget to add external fuses. For that matter, Renogy ought to bump the price up $10 and include them.
| Brand | Renogy |
|---|---|
| Material | Aluminum |
| Product Dimensions | 6.45"L x 4.31"W x 1.76"H |
| Item Weight | 14.1 Pounds |
| Connector Type | Barrel Connector |
| Included Components | cable |
| AC Adapter Current | 30 Amps |
| Maximum Voltage | 12 Volts |
| Maximum Power | 100 Watts |
| Manufacturer | Renogy |
| Part Number | 107.4, 49.8, 3.5 |
| Item Weight | 14.1 pounds |
| Country of Origin | Thailand |
| Item model number | KIT-STARTER-100D |
| Is Discontinued By Manufacturer | No |
| Size | 100W Panel+PWM 30A Controller |
| Color | Off-Grid System |
| Style | Cables+Mounts |
| Power Source | Solar-Powered |
| Wattage | 100 watts |
| Item Package Quantity | 1 |
| Special Features | Lightweight Design |
| Batteries Included? | No |
| Batteries Required? | No |
| Warranty Description | Power Output Warranty |
