How much power will I need

[steiny]

I just purchased a kiwi 23b. We will be camping this summer with a infant and will be needing to run the furnace. I am looking at solar panels but not sure how much juice the furnace needs to run at night. The only thing that we will be running off the batteries is lights and the furnace. There is currently only one battery but plan on installing two group 27 batteries. Any help would be appreciated.

[oldmanAZ]

Congratulations on the Kiwi and welcome to the JOF.

This is going to be difficult to quantify: The furnace fan is a large user of power. How much it will use depends upon how long it runs. Of course that depends on how cold it is outside and the setting of the furnace thermostat.

There is a solar group within the JOF and one of them may respond soon to help you with your solar questions.

The following info may not be of much help, but I wanted you to know about our experience last fall: We have 2 group 24 batteries and after staying in a full-hookup CG to top off the batteries, we boondocked. We were comfortable for 3 nights. On the 4th night, about 6AM the batteries just barely ran the furnace fan. I had to start the truck to keep the power from dropping too low.

Our trailer is a bit larger, but yours is a hybrid. Our thermostat was set at ~62deg F. At night the temp dropped to around 32deg F. Daytime temps were in the low 80s. We minimized use of our LED lights and didn't watch TV or use any other 12v devices.

If you can alternate between boondocking and sites with utilities, you could experiment with going 2, then 3, then 4 days and watching your battery voltage. CAUTION: After boondocking, just towing your TT to a new site WILL NOT bring your batteries back to full capacity. You will need to charge them through your trailer converter for at least ONE DAY.

Good luck and have fun camping. Back in the day when the DW and I camped in a popup with an infant, we didn't have a furnace. We had to do our camping when the temps were in our 'comfort range.'

[Mustang65]

CONGRATULATIONS on the JAYCO!!!

...and WELCOME TO JOF!!! The members here are GREAT!!! There is a lot of GREAT information to be found here. I am sure that you will have information and pictures to share with us... so please do!!

I can give you a little (REAL TIME) insight on the heating requirements as we are in the Blue Ridge Mtns (Hiawassee GA) as we electronically speak. The temperature at the moment is 28 degrees outside the TT and it is 69 inside the TT. The temp today will be 62 for the high.

Ok, so with 250 watts of solar, MPPT Solar controller and 260Ah batteries (2 6VDC Trojan T145 batteries) of which I can only use 130Ah of (50% rule = about 12VDC). The batteries were topped off by 3PM yesterday, we have 10 LED lights (840 Lumens Natural White each) on from the morning until we go to bed at night. DW likes it nice an bright (not WHITE light but more natural feel) in the TT. The TT heater fan is running off of batteries only (TT's battery charge controller has been turned off since I installed SOLAR).

So the heater started up last night around 6pm and comes on about twice an hour overnight. The battery level was at 12.8VDC at 9 pm, this morning I woke up and it was at 12.5VDC. If you had one 85Ah marine/RV battery, you would have been below the 12VDC lower battery limit.

For camping use, I do not recommend less than 200 watts of SOLAR panels or less than 220Ah of battery power (of which you can only use 110Ah). I also recommend installing them on the roof of the TT and if you mount 2 100 watt panels try to mount one at the front of the TT and one at the rear of the TT roof, this way if there is any shading there is a chance that one will not be shaded. Also electronically connect them in parallel, as shading will not affect the output of the unshaded panel. If you go with the requirements above and stay above the 50% rule your batteries will be charged the next day by 3pm. Also remember that everyday is not a bright sunny day, so that is why I recommend 200+ watts of SOLAR. Don't forget if there are kids in the equation, they will up the Ah's used also.

You will need to get a battery monitor to mount inside the TT, so you can keep an eye on the batteries condition.. an expensive one is not necessary.

The thing to remember, as we move to summer temperatures the Ah used for heating will be available for other things....

For a little more info join the RVing with SOLAR social group... we cover a lot of SOLAR and BATTERY topics... even have a step by step installation process.

A brand that a lot of members have RAVING reviews on is RENOGY... check out the social group or search RENOGY, I am sure that the members that have installed RENOGY systems will give you a little more information on their systems.. It is a very affordable package.

Also remember, that a SOLAR lifestyle takes practice...

Good Luck,
Don

[Seann45]

Yes to everything Don just said... do go with 2-6 volt batteries as they give better capacity.. and longer life
Now please do be aware that you will be using more than just the lights and furnace.. the fridge on propane still needs 12 VDC to run, even turned off the radio uses power, the water pump, the propane detector... if you stay just on the 12V side 200 watts of solar and a good MPPT charge controller can be had for around $400.00

[Subaru297]

I know this is an older thread but thought I would add a little math for future readers....

Furnace fan draws 7-12 amps on average I think. Let's use 10 amps.
So if the furnace fan ran all night. 8 hours it would draw (8h*10A) 80Ah

Depending on the temperature and how often it runs is the biggest factor. If it is on 25% of the time then you are down to 20Ah for a night. Add in the 1 amp parasitic draw that runs 24/7. 24Ah's per day.

Given a typical 80Ah (40Ah usable capacity) group 24 battery one 24 hour period will drain that battery without any charging. 20Ah from the furnace and 24Ah from parasitic loads.

Two group 27 batteries should give you 200Ah or 100Ah usable. Two days will use up 88Ah given my rough assumptions above. Three days will be pushing it with no charging.

300Watts of panels keeps us in the green pretty much indefinitely but our electricity use is a bit lower than most I think.

Cheers