No solar needed???

[pickjare]

M. Hey, I just wanted to mention my experience with Trojan T105's after a 3 night camping trip for those of you who are wondering about solar power. We camped in Idaho mountains at about 7400 feet. It was colder than we hoped. In mornings the Creek edges were frozen with very thin layer of ice wherever there was very little current. I didn't have thermometer but that proves definitely below 32 F. I have 2 t105's.
I have spent hours on this forum reading up on solar power and just can't decide if I need it or I just want it, but no generator and no solar on this trip. I have a 25,000btu furnace, Atwood I think, don't know model but it draws 6.5 Amps when batteries are at full charge. I set thermostat to 60 degrees each night, ran lights very little and water pump pumped about 65 gallons. Used fridge on propane and water heater is DSI type. Listened to CD radio for about 45 minutes. I have never checked current draw on those units since I suspect it is very little. Also have propane detector drawing 50 MA.
I have read many posts about people noting furnace really uses a lot of power. Same with that little propane detector. We were a little worried about hurting our new batteries--running them too low, but cannot afford solar so we just went camping, tried to be easy on electrical needs and figured we would just see what happens.
Got home Sunday afternoon. Batteries sat for 24 hrs unused in any way. This afternoon I measured open circuit voltage at 12.22VOLTS. I do not have a hydrometer, but as per Trojan website this 12.22V indicates these batteries are sitting at 60% charge remaining.
I found this very interesting. As long as open circuit voltage is accurate, the idea that the furnace will just drain the batteries real fast appears not to be true in every case. If any of you are on the fence about solar power, and are weekend campers like us, I would say go camping as you normally do and see what kind of charge your batteries have left. Maybe that furnace isn't so bad after all. Maybe solar isn't needed.

[Almot]

RoyB wrote:
when they drop down to around 12.0VDC then we fire up the generator when allowed and recharge the battery bank back up to its 90% charge state which takes around three hours of generator run time...

Get that solar already, Roy 🙂
Then you won't have to run generator for more than one hour, solar will do the rest. Or run it 3 hours every other day and bring them to 99.9% by the evening.

[Byrogie]

Yes, we have solar now to top up batteries when away from our seasonal spot, but previous to that, no problem for 3 nights of furnace with the same Trojans.LED lights and fridge and water heater on propane.
Having said that, need generator for when we run the furnace day and night...

[RJsfishin]

Good report.
If I was "camping" (many definitions) for a couple 3 days trying to make 2 batteries last w/o recharging, it "maybe" wouldn't kill me to do it,....even in cold weather. But it sure would throw a cramp into my "camping" lifestyle.
Back is the old.....and younger days, (when we dint feel pain) we did it w/o any batteries at all,.....probably defined as "real camping".
This day and age, if it was cold, and I didn't have catalytic heat, just the furnace and the tv/sat would burn my 110 (available) amp hrs the 1st nite.
Do I need solar.....or genset, ?? you bet I do ! 🙂

[brulaz]

Just one thing: you do want to get your batts charged back up to 100% as soon as you get home. They don't like sitting in a partially discharged state.

[grizzzman]

pickjare wrote:
Though I have not actually checked for power at my 7-way, I pulled the B+ fuse for that charge wire so those batteries cannot be charged by tow vehicle. My pickup has 321,000 miles, I don't want the alternator working harder than necessary.
I just want to emphasize that it appears we lost 10% battery capacity per 24 hrs of camping use which is drastically different than so many others experienced. And not what I expected. I will check that pin for power because if I pulled wrong fuse and batteries did charge, this is way off, thanks for catching that.
Is the following a correct understanding of amp-hour ratings: If furnace used 6.5A and ran for an hour, does that mean I just used 6.5Amp-hours of the total available 225?

About all you would get would be around 5 amps from the alt. On the typical 10 gauge charge wire. And yes 6.5 AH but for long battery life 50% or around 112AH at the 20 hr rate(it would do you good to learn about the peukert's law)

[pickjare]

Though I have not actually checked for power at my 7-way, I pulled the B+ fuse for that charge wire so those batteries cannot be charged by tow vehicle. My pickup has 321,000 miles, I don't want the alternator working harder than necessary.
I just want to emphasize that it appears we lost 10% battery capacity per 24 hrs of camping use which is drastically different than so many others experienced. And not what I expected. I will check that pin for power because if I pulled wrong fuse and batteries did charge, this is way off, thanks for catching that.
Is the following a correct understanding of amp-hour ratings: If furnace used 6.5A and ran for an hour, does that mean I just used 6.5Amp-hours of the total available 225?

[korbe]

Yes, your story did not surprise me. We camp with the same setup and enjoy up to 7 days while keeping the battery above 50 percent. But no furnace on the 7day trips.

[RoyB]

We always followed the rule ONE NIGHT ONE BATTERY when having to run the Furnace fan...

We always watch the DC VOLTAGE with a real DC voltmeter and when they drop down to around 12.0VDC then we fire up the generator when allowed and recharge the battery bank back up to its 90% charge state which takes around three hours of generator run time... Then we are good to do this all over again the next day/night run off the batteries...

Roy Ken

[Almot]

Furnace is more efficient than running inverter and 120V heater.

Catalytic heater is more efficient than running a furnace. I could provide a number but math rules won't let me divide by zero 🙂

Spreadsheets and estimates are useful for planning a solar.

Your trip didn't require a solar.

Some trailers are insulated better than others.

[time2roll]

Yes as much as many call for some detailed spreadsheet to do some energy audit... I far prefer a trip report. Not sure how long the drive was but you probably put some charge back in on the way home.

Save the solar for when planning a trip of extended length.

[2oldman]

pickjare wrote:
M..the idea that the furnace will just drain the batteries real fast appears not to be true in every case.

No it isn't, and it's far more efficient than running an inverter.

Nice report.