6V or 12V batteries - Cold weather furnace issues

Brobbs12 · 11-10-2022, 03:44 PM

Do you cold weather camp? Do you use 12V or 6V batteries?

So I’ve owned my Bullet 247BHSWE for 6 years now. It came with two 12V batteries and I used them for 4 years. Could have gotten 5 but decided to change to two 6V. Living in Montana, I cold weather camp during hunting seasons in below freezing temps several times per year. When I had the 12V batteries, I never had an issue with my furnace coming on with battery or when plugged into the generator.

Last year (2021 and first year with the 6V batteries) I couldn’t get my furnace to ignite on battery. I had to fire up the generator to get it running. Now I generally run the furnace on the generator anyway but if it’s cold, I wake up, turn on the furnace on in the morning, jump under the covers until the camper is a tad warmer, then get up and turn on the generator. At the end of hunting season, I pulled the batteries and put the camper away. Talked to the RV dealer and he said it sounded like I had a bad battery.

This year in April, I got the camper ready for the season. Charged the batteries, checked them with the multimeter and load tester and they were good. This fall, again I couldn’t get the furnace to ignite on battery power. Had to have the generator running. Then yesterday the furnace wouldn’t even come on when plugged into the generator. I wish I’d had my multimeter to check but didn’t.

Talked to the RV dealer and they said even when plugged into the generator, there might not have been enough volts to ignite the furnace? That makes no sense to me though. Earlier this year, I tested the batteries with the generator running and it was showing 13.XX volts. I’m just wondering if 6V batteries suck when it comes to cold weather camping and thinking of going back to 12V next year.

Sorry for being long winded and if you made it this far, thanks for reading! I just don’t get it.

ChuckS · 11-10-2022, 04:24 PM

I’ve been running two GC2 golf cart batteries for over 7 years now.. I dry camp often here in Idaho in cold temps at night.. the two GC2 batteries are heads and tails better than the two Grp27 batteries I originally had..

I would check the battery terminals and cable ends ..

I would then check the grl7nd cable from battery to frame..remove the frame cable end and make sure you have bare metal for a good bond

If the blower motor comes on and the furnace won’t fire you also have other issues at the furnace itself to look at..

After 7 years my two GC2 batteries specific gravity cell per cell is as good as the day I installed them

Brobbs12 · 11-10-2022, 05:12 PM

Thanks for the reply. Yea the blower kicks on but furnace didn't ignite.

Just got home and checked the battery with the meter, 12.11 volts. Plugged it into the house outlet and reads 13.60 so charging. I then turned the furnace on and it ignited just fine.

So then thinking maybe generator not putting out enough. Checked it and it's reading 121 on the outlet so appears to be fine.

Canonman · 11-10-2022, 06:11 PM

" I’m just wondering if 6V batteries suck when it comes to cold weather camping and thinking of going back to 12V next year. "

Since they are both lead acid batteries there isn't any difference in how they handle the cold. We dry camp in cold conditions and have noticed no difference after upgrading to 6 volt batteries.
I'm a little confused though. If the fan is running (that's a pretty fair 12 volt load) but the furnace won't lite, is the DSI not seeing enough voltage? Would seem to me low battery voltage would affect the fan first.
Plus, the generator should be delivering 120 vac to the converter and from there the converter should be charging the batteries at the same voltage as with house current.
Hope someone can help me understand too

travelin texans · 11-10-2022, 09:24 PM

Just a thought!
If you wired 2 - 6 volt batteries the same as the 2 - 12 volts (parallel) you only have 6 volts going to the 12 volt furnace. The 6 volts need to be wired in series, + of battery A to - of battery B with + of A to coach & - of B to ground.
Also if testing voltage while plugged in o4 generator running your reading the output of the converter not the battery voltage.

pasayten · 11-11-2022, 12:05 AM

I have 2 x 100ah LiFePO4 (Lithium) heated batteries... Great cold weather performance... :-)

Brobbs12 · 11-11-2022, 09:52 AM

Update: So after having my camper plugged into a house outlet for 15 hours, I unplugged it. checked the batteries and read 12.96 volts. Turned on the furnace, fan kicked on, furnace ignited. I held the meter on while the furnace was running and within 3-4 minutes, it was down to 12.44 and dropping every few seconds. Turned the furnace off and it then read 12.56.

So now I'm really just thinking both the batteries were fully discharged, even when plugged into the generator and couldn't provide enough to start it? Also wondering if one or both of the batteries are just not holding their charge very well. I'm done for using it for the year so I plan to fully charge the batteries, and test them on a weekly basis to see what they drop to.

Still think next year, I'll go back to two 12Volt batteries.

**chuckster57** · 11-11-2022, 12:22 PM

If the fan is starting but no ignition on battery, my first thought would be weak batteries. The fan has to turn fast enough to move the sail switch enough for the signal to the control board that is go for ignition.

Brobbs12 · 11-11-2022, 01:35 PM

I guess what still confuses me is why it wouldn't ignite when plugged into the generator? I guess I thought the generator would provide the power even if the batteries are weak.

But I'm barely above stupid when it comes to mechanical or electrical things.

CampNBrew2 · 11-11-2022, 01:46 PM

Quote:

Originally Posted by Brobbs12

I guess what still confuses me is why it wouldn't ignite when plugged into the generator? I guess I though the generator would provide the power even if the batteries are weak. ��

This would be my guess as well. Is the furnace fan that high a load that the converter won't provide adequate VA to charge weak batteries and turn the blower simultaneously? It appears so. Can you watch the voltage while on generator with the furnace starting/running while also in charge mode?

**flybouy** · 11-11-2022, 01:47 PM

Quote:

Originally Posted by Brobbs12

I guess what still confuses me is why it wouldn't ignite when plugged into the generator? I guess I though the generator would provide the power even if the batteries are weak.

But I'm barely above stupid when it comes to mechanical or electrical things. ��

If your batteries were fully discharged then using the generator should power the converter, however, the converter may be using nearly all of its output recharging the batteries. In other words, the converter doesn't have the output capacity to charge the battery AND run a high Amp appliance simultaneously. It quite possibly could take an hour or several hours before the batteries chege sufficiently for the converter to throttle back from bulk charge mode.

CampNBrew2 · 11-11-2022, 02:00 PM

Flybouy,
Exactly what I was wondering, the same time you were typing your reply. This makes the most sense.

Brobbs12 · 11-11-2022, 02:01 PM

Quote:

Originally Posted by flybouy

If your batteries were fully discharged then using the generator should power the converter, however, the converter may be using nearly all of its output recharging the batteries. In other words, the converter doesn't have the output capacity to charge the battery AND run a high Amp appliance simultaneously. It quite possibly could take an hour or several hours before the batteries chege sufficiently for the converter to throttle back from bulk charge mode.

That makes sense. Thanks. It's a champion 3100 watt generator if that matters.

**flybouy** · 11-11-2022, 02:55 PM

Quote:

Originally Posted by Brobbs12

That makes sense. Thanks. It's a champion 3100 watt generator if that matters.

3100 watts divided by 120v equal 25.8 amps, if that running watts and not "peak" watts. Either way, it should be sufficient as long as you're not running other high amperage loads like blow dryers, space heaters, etc.

**JRTJH** · 11-13-2022, 08:44 AM

A 55 amp WFCO converter is "rated at 13.6VDC" so that's 55x13.6= 748watts of output power.

That same converter is "powered by 120 VAC, and the 748 watts input requirement is around 6.2 amps. Even considering a 10% loss in the converter, that would only be about 7 amps max which is 840 watts to run the converter/charger. With a 3100 watt generator, unless you're running the air conditioner and/or some other "high wattage appliance" chances are pretty slim that you'd be maxing out the generator output.

I'd focus more on the DC wiring/battery capability (load test the battery system to check for a bad cell) and verify that all the wiring connections/battery terminal connections and ground connections are clean, tight and not corroded.

There is no reason why your furnace shouldn't work properly when being powered by the converter which should work equally well on shore power or the 3100 watt generator (assuming you don't have any additional "heavy load" )

TimC · 11-15-2022, 06:52 PM

I cold weather camp often. Used to have problems with my 2 12v lead acid batteries. I upgraded to lithium and haven’t had an issue since.

Brobbs12 · 11-17-2022, 01:53 PM

Quote:

Originally Posted by JRTJH

A 55 amp WFCO converter is "rated at 13.6VDC" so that's 55x13.6= 748watts of output power.

That same converter is "powered by 120 VAC, and the 748 watts input requirement is around 6.2 amps. Even considering a 10% loss in the converter, that would only be about 7 amps max which is 840 watts to run the converter/charger. With a 3100 watt generator, unless you're running the air conditioner and/or some other "high wattage appliance" chances are pretty slim that you'd be maxing out the generator output.

I'd focus more on the DC wiring/battery capability (load test the battery system to check for a bad cell) and verify that all the wiring connections/battery terminal connections and ground connections are clean, tight and not corroded.

There is no reason why your furnace shouldn't work properly when being powered by the converter which should work equally well on shore power or the 3100 watt generator (assuming you don't have any additional "heavy load" )

Thanks. I pulled the batteries and put the camper away for the season. It'll be next April/May before I get it back together. I charged up the batteries and am checking them every couple days to see if/how much they drop just sitting in my garage.

I'll report back next spring.

**JRTJH** · 11-17-2022, 06:51 PM

You might consider load testing your batteries so you can plan ahead. I would not buy new batteries to sit in the garage through the winter, but knowing now whether or not you'll need new ones will give you all winter to make decisions on whether to just replace what you have, upgrade to larger lead acid batteries or even upgrade to a different battery technology. Waiting until spring, finding out your batteries are "toast" and then scurrying to make decisions, find parts, get information on whether the current converter will work, etc could put you at a disadvantage with a "Friday departure looming ahead on a Wednesday afternoon with two days of overtime scheduled before departure"...

So... Any auto parts store will load test your batteries and tell you if they are good or bad. Or, if you find yourself walking around Harbor Freight with a 20% off coupon in your pocket, they have a 6volt/12volt battery load tester for $15. It'll do the same basic tests as the "high dollar Auto Zone tester"... Actually, the local AZ here uses a HF tester just like my $15 one.... Anyway, finding out if the batteries are good or bad now, will give you all winter to get a "good battery system planned, located, ready for spring"....

Here's the link to the battery load tester I have: https://www.harborfreight.com/100-am...ter-61747.html

Brobbs12 · 11-18-2022, 08:04 AM

Quote:

Originally Posted by JRTJH

You might consider load testing your batteries so you can plan ahead. I would not buy new batteries to sit in the garage through the winter, but knowing now whether or not you'll need new ones will give you all winter to make decisions on whether to just replace what you have, upgrade to larger lead acid batteries or even upgrade to a different battery technology. Waiting until spring, finding out your batteries are "toast" and then scurrying to make decisions, find parts, get information on whether the current converter will work, etc could put you at a disadvantage with a "Friday departure looming ahead on a Wednesday afternoon with two days of overtime scheduled before departure"...

So... Any auto parts store will load test your batteries and tell you if they are good or bad. Or, if you find yourself walking around Harbor Freight with a 20% off coupon in your pocket, they have a 6volt/12volt battery load tester for $15. It'll do the same basic tests as the "high dollar Auto Zone tester"... Actually, the local AZ here uses a HF tester just like my $15 one.... Anyway, finding out if the batteries are good or bad now, will give you all winter to get a "good battery system planned, located, ready for spring"....

Here's the link to the battery load tester I have: https://www.harborfreight.com/100-am...ter-61747.html

Good advice. I did borrow a load tester last July and they both read good. But that was in July and I should have one on hand. I was using a really old charger so purchased this one that had really good reviews https://no.co/genius10

I also watched this video that helped me understand a little more about battery care and maintenance

https://www.youtube.com/watch?v=WFPcV9_1frE

Thanks again.

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