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Rbertalotto's avatar
Rbertalotto
Explorer
Jun 23, 2016

A Solar update / review....

Last year I installed 280 watts of solar on my 20' toy hauler. I also outfitted this trailer as a mobile office. You can read all about the details here:

www.rvbprecision.com

I'm what you might call a "Reverse Camper"......I camp Tuesday to Thursday, back in the house for the weekends. This works out great because I rarely have an issue getting a great camping spot mid week.

Usually I'm camping in state parks. Nice accommodations but lots of trees and shade which really limits my solar generation.

This week I'm on the beach. Horseneck Beach State Reservation in Westport, MA....Which BTW is a fantastic place to camp and about 7 miles from my house! A bit strange as everyone parallel parks along the roads. No backing in or pull through. Huge sites with lots of space between campers. The sunsets are simply magnificent! And zero trees! LOTS of sun....

Working out of the trailer I have the following devices operating off the batteries at least 10 hours per day
Verizon HotSpot
WeBOOST Cellular Booster or ALFA 36 WiFi Booster
28" 12v TV or Radio
12V Laptop charger
12V Cell Phone charger

Working intermittently I also use:
Kureg coffee machine off inverter (5-6 cups of coffee a day) (56amps for 2 minutes each cup)
water pump
LED lights
dvd player (3 hours a day)

So I decided to run a test. Usually my batteries never get below 80% according to my TriMetric monitor. And even in the shade, by 5pm the batteries are usually back up to 95-97%

This week with no shade, no clouds and being the summer solstice, I couldn't ask for more sun. So I decided to run a best situation test.

I turned both TVs on and left them on all night. I had my laptop totally discharged and connected it to the 12V charger same with my phone and the MiFi hotspot. And I left the WeBOOST on all night. I also left the ALFA 36 WiFi booster on all night.

So we can do the math....These devices draw:
Each TV 2amps
WeBOOST 1.4amps
MiFi 0.3amps
MacBook Air Charger 2.3amps
ALFA 36 0.3amps
Iphone 5s charger 2amps

All the above was verified through the TriMetric monitor

The test was started at 10pm. When I woke at 6am, the TriMetric was reporting my battery voltage at 12.2v and 55% battery capacity

I cooked breakfast with no electrical use except intermittent water pump. 25 seconds total use. I then left the trailer to run a couple errands. I returned at noon and the batteries were charging at 14.4v and the solar panels were dumping 4.7amps into the batteries. The TriMetric reported 92% battery capacity. (I've witnessed the solar cells dumping a max of 17.8 amps into the batteries at 11am the day before this test) As the batteries reach total charge, the Bogart solar controller adjusts the current and voltage as needed.

Not using any 12v devices, the solar cells tapered off to 2.3 amps and then 1.7 amps and voltage was at 13.7v and the TriMetric reported 100% capacity by 1:30pm.

I then started using 12V devices and I could see by the TriMetric, that although I was charging the laptop and running the radio, the solar was more than keeping up with the demand up until 5:30pm where I started to see negative numbers as I was using more electricity than the setting sun could replace.

Although I've not run my generator since I've installed this solar system, I expect that now with full leaves on the trees, the next time I'm in a shaded park, I might need a bit of generator.

Usually this trailer is a means to an end......I don't usually camp to just camp. I use the trailer to attend motorcycle events, shooting events, grandkid sporting events where I'm usually out on a grassy field or in a parking lot with no shade.

All around me, here at the beach, the generators start at around 4pm and run until 10pm. There are no trees to block the sound but fortunately the crashing waves mask it quite well.

When I hear these generators starting up, I just smile.......Loving my solar!
  • Almot wrote:
    Get 150W inverter for $20, Bill. For small things like laptop charger etc. No installation required.

    700W Keurig is a poor match for 200W solar and 2*T105. With (probably) few other big loads you'll have to run generator every morning anyway. Then let the solar finish the charging off.
    If that is the case it wont be the end of the world. Right now with my 2 Yamahas I have to start both generators just to make a cup of coffee because between the charger/converter drawing a lot in the morning once power is applied and my 1475w Keurig, it trips out the generator unless I run 2. So 700w might let me start only one.
  • Cuz I'm just learning this stuff. the 700w coffeemaker brews in 2 min, that's 2800 watts a minute or 45 watt hours, correct?
  • bill-e wrote:
    Cuz I'm just learning this stuff. the 700w coffeemaker brews in 2 min, that's 2800 watts a minute or 45 watt hours, correct?
    Amps are usually used. 700W/12V = 58A or about 1Ah for the battery discharge for each minute, 2Ah total.

    Don't know where you came up with 2800W as the coffee maker draws 700W a minute.
  • Almot's avatar
    Almot
    Explorer III
    bill-e wrote:
    the 700w coffeemaker brews in 2 min, that's 2800 watts a minute or 45 watt hours, correct?

    No.

    700W*2min/60min=23 WH.

    In battery world we measure it in AH, not WH.
    23WH/13V= 1.8 AH. Make it 2 AH after inverter losses.

    But the battery will lose more than 2 AH, here is why:

    700W/13V= 54A current, make it 60A after inverter loss. Batteries hate high 60A current, their charge is dropping then faster than It "should've". This is called Peukert effect. 2 AH consumed by Keurig will result in 4 AH or 5 AH drop in battery charge (off the top of my head, don't want to run Peukert numbers now).

    So, 700W Keurig is still doable without generator. You will need 1,000-1,200W inverter for that. Getting it much bigger won't make sense with 2*6V batts. People sometimes install 2,000W inverter for microwave, but MW is too high load for your 2*T105. And so is your other 1,400W Keurig.
  • Almot, Thanks.

    I got my T-105RE's installed today (They were recommended to me by the solar company that I purchased my Zamp kit from as a good match for the 200w kit. The panels got held up in shipment so I may not have them for this next dry camp in a couple of days.

    My biggest concern is keeping the batteries charged so I can run my cpap at night on them. Also, I sometimes have to take my pup so I could want to have a 12v fan running in the camper during the day and also have enough for the cpap at night...hopefully this will work. The coffeemaker is only icing on the cake if that works.