Sundtman: Truck Camper Solar Setup

System · March 2017

This discussion was created from comments split from: newbie solar truck camper setup.

Sundtman · March 2017

Hello Bill. If the thread is still active i'd like to jump in here and have your opinion an a solar system that I am planning on installing on a truck camper. This system will be almost exactly the same as jancsi. I love his diagram and will utilize it for all the wiring sizes and breakers/fuses except I won't put any fuses coming off the panels.

My system will consist of:
2 ea 100 watt Renogy monocrystaline panels
Bogart Engineering SC-2030 charge controller
Bogart Engineering Trimetric TM-2030-A battery monitor w/ battery temp sensor
2 ea Crown 6 volt GC2 batteries, either 205 Amp HR or 220 Amp Hr
Xantrex 1000 Watt inverter

I want to install the 1000 watt inverter to run a 600 watt electric perk coffee pot, a 750 watt toaster and (not for me) a 800 or 1000 watt blow dryer. these items will only be used for 10 or 15 minutes each day so not alot of amps being drawn.

Here is my power consumption estimate:

12 volt appliance	AMPS	x Quantity	x hrs per day	"=" total AMPS per day
water pump	5	1	0.5	2.5
Fant. 3way fan set on M	2.29	1	0.5	1.145
Furnace	3.4	1	3	10.2
12 volt stereo	0.8	1	3	2.4
LED lights 36	0.123	4	2	0.984
cell phone charger	3	1	2	6
CO detector	0.05	1	24	1.2
LP gas detector	0.05	1	24	1.2
				DC Total
				25.629
120 VAC appliance	Using DC to AC inverters
Toaster	75	1	0.125	9.375
Coffee Maker	60	1	0.25	15
Hair blow dryer	80	1	0.167	13.36
				AC Total
				37.735
Total weekly Amps Calculation
Amps Per Day	x # of days of use per week			"="Total Amps
63.364	1			63.364

I live in New Mexico and do most of my camping in New Mexico, Colorado, or Utah. So I have pretty good solar exposure. I typically only camp for 2, 3 or 4 days although I would like the system to be functional for a week or more. I do have a honda 2000i generator but I'm trying to get to where I don't ever need to run it. Based on your calculations above, the 200 watts of solar panels are barely adequate to charge 200 amp hrs of batteries. I'm wondering if I should buy 205 amp hr batteries or 220 amp hr. More amp hrs should be better unless the solar panels can't keep them fully charged. I'd like your advise here.

I know you said that the 1000 watt inverter was too much for jancsi but I would need at least 1000 watt to power the 600, 700, and 800 watt 120 volt appliances. Any problem here?

If you would look through my power consumption numbers and see if they are accurate I would appreciate it. I don't use much power during the day. I only need the big power for breakfast, then the water pump intermittently during the day and lights after dark but the lights are all LED so not much power used there. The biggest drain and the main reason I want to have a solar system to recharge the batteries is the furnace fan blower motor. I've had the furnace run a single 12 volt deep cycle battery all the way down in 1 night. Don't want that to happen again.

If you can recommend exact size and type/brand of circuit breakers that would be appreciated.

Your thoughts and input are greatly appreciated. like most, I've never done this before and I only know enough about electricity to be dangerous.

Thanks,
Dan

BB. · March 2017

Welcome to the forum Dan. I moved your questions to your own thread... That way we can discuss your installation specifically without confusion from the original thread.

First--Highly suggest conservation. The CO detector can be replaced with a unit that takes ~3 AA batteries. The propane detector--you may not find AA battery powered unit.

I don't know if you measure the current... The furnace fan has been closer to 8 amps from what I have seen (maybe larger fans in RV Trailers). 3 amps for a cell phone charger sounds high--Closer to 0.5 amps? If you play the radio a lot--You might look for battery powered or rechargeable battery devices (cell phone + blue tooth speaker for example).

But--The above are just "small change" when compared to your other loads of Toaster, Coffee Maker, Hair Drier.

There are two basic criteria for designing battery banks. One is the average power (or AH) * Hours per Day of usage (like you did). Multiply that by 1-2x for one to two days storage and 1/0.50 for maximum discharge (use 1/2 battery capacity) for longer life--Or roughly 2-4x your daily load for battery AH capacity.

63 Amp * 1 day storage * 1/0.50 max discharge = 126 AH minimum (1 day storage--Can be "OK" for weekend use)
63 Amp * 1 day storage * 1/0.50 max discharge = 252 AH nominal (2 day storage--For full time off grid usage)

The second is based on your peak Wattage (Amps) of power usage... Nominally, for deep cycle flooded cell storage batteries you should aim at ~C/8 discharge (nominal) to C/5 (minutes of loads)... I.e., if you have 80 load, then:

80 amp load * 8 hour discharge rate ~ 640 AH "nominal"
80 amp load * 5 hour discharge rate ~ 400 AH "minimum"

That is quite a large battery bank... The battery bank has to be several times larger because of your high peak loads vs your over all average daily energy usage.

You do have choices--Use AGM or LiFePO4 batteries which can output higher discharge rates (C/1 to even, in theory, C/0.25---I.e., discharge your battery in 15 minutes).

Before we talk about wiring/breakers/etc... I would highly suggest looking for alternatives for you large energy draw devices. The Toaster--A toast holder on a gas cook top. And a propane powered "Mr. Coffee" is easy too.

However--The hair drier--I have not heard of anyone that has found an "off grid" friendly hair drier solution (other than brushing in sun/wind).

This is what I would be addressing first. Do you have a battery type/AH capacity specified yet?

-Bill

dennis461 · March 2017

12VDC hair dryers are available with less watts than your selection. Look for a marine pro 12-volt.

Sundtman · March 2017

Thanks for the quick reply. I am planning on buying 2 Crown 6 volt golf cart batteries, either 205 AH or 220 AH. I would prefer the 220 AH for more capacity but one of my main concerns from reading other posts is weather 200 watts of array will keep them fully charged. In my power use/consumption table some of those numbers came from a table I found in another post. The CO and propane monitors are what was already in the table so I haven't checked to see exactly what mine consume. If I play music it will be from an Iphone through blue tooth speakers although the camper does have a built in stereo/cd player. The 3 120volt appliances are all luxuries I was trying to be able to run with an inverter. The blow dryer was really an after thought for the Mrs. I am hoping to be able to make a pot of coffee and toast without firing up the generator. I do have a coffee pot and toaster that work on the propane stove, it just takes a long time for that first cup of coffee. These Items will only be used for 5 or 10 minutes per day. I was hoping that they wouldn't put enough of a drain on the batteries so that 200 watts of solar would be able to recharge the batteries. Just a little decadence and extremely high priced coffee and toast! You kind of lose me when you start calculating the discharge rates but I would never be pulling 80 amps for 5 hours. If I was using any of the 120V appliances I would only be using 1 at a time. I'm pretty limited on space on the roof top. 2 100 watt panels is all I have room for and the camper was built with a battery compartment that holds 2 6 volt golf cart batteries so that's pretty much the limit too. It's a Hallmark Ute pop up truck camper. If I should forget about the inverter and running 120V appliances it's not that big of a deal. The main thing I want to accomplish is recharging the batteries after using the furnace at night in the spring and fall. Thanks for your help and input.
Dan

Sundtman · March 2017

Dennis461, thanks for the heads up about the 12V hair dryer.

Estragon · March 2017

Running the hair dryer etc. may just pull the voltage down on a small flooded bank below the low battery cutoff on the inverter. You would then have to wait for voltage to recover, and start your toast again. Using a rack and propane might be faster.

littleharbor2 · March 2017

Those small, high volume, low pressure air pumps that are used for blowing up air mattresses and such work pretty well as makeshift blow dryers without heat. They come in 110 Vac, 12 Vdc and battery models

baphenatem · May 2017

Ah, the things we'll do to have the comforts of home while "camping". Get used to pan-fried toast, and buy a Bialetti Moka Express pot and the electrical usage will be significantly lessened, albeit at the expense of some propane. Ditch the hair dryer and buy a Plat-Cat or other radiant propane heater and you should be able to get along quite well with 200 Watts of solar.

BTW, are you going with a pair of 100's because they're what's easily available or because they are what fits? If you can squeek in a pair of 160 or 180 Watt modules without shading issues you would be making 50-60% more power.

Sundtman: Truck Camper Solar Setup

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