Battery Life on a trip

[ThomasC]

I was talking about running your propane furnace. They take a lot of power and you never know what kind of weather you will run into. You can take the "chill" off if you want but I want heat. The most miserable night that I spent in my life was near Scranton PA. It went down to 15 and the 2 year old battery that was fully charged from driving died in an hour.

Then a year later in my brand new Bigfoot with the brand new not so special battery that it came with didn't quite make it through the night. That battery was fully charged to because I was plugged the night before.

So my point was if you are going to run the propane furnace in your RV one plain old lead acid battery won't cut it.

[thrifty bill]

Along with the furnace fan of course, you have the CPAP machine draw.

People who rely on battery power tend to have a significant investment in Lithium batteries and a lot of solar panel.

I’d set up in your driveway for a few days. Use everything you plan to use and see how long your battery lasts. I don’t have a CPAP so my experience will not match yours.

My favorite state and national parks out west do not have hookups. Nor will they allow generators in the evening or night.

[Glenn Baglo]

Originally Posted by ThomasC

So my point was if you are going to run the propane furnace in your RV one plain old lead acid battery won't cut it.

I guess it depends. I have a single group 27 lead acid battery. I run the furnace in the evening and at night. I watch state of charge with a voltmeter. On the third day I've got to charge ( approaching 50 per cent charge on the battery ).

Fridge is on propane, light are LED. I have two 40-watt portable solar panels and a 1,000 watt generator ( for backup ).

[Perryb67]

Originally Posted by Civilguy

As John mentioned, the accuracy of readings taken with the $12.99 voltage meter could benefit from shutting off loads and waiting a few minutes to see if there's any change in the displayed voltage.

If the Casita has a single lead-acid 12-volt battery, as most do, then a volt meter and a small notebook can provide plenty of information accurate enough to protect the battery on a cross-country trip.

A Victron battery monitor at $206, plus any associated materials and labor costs for installation, might be a good investment for collecting more data. Or, it might not.

It would certainly be wise to gather information on total daily power usage to guide any significant investment in batteries and solar capacity so that the system could be properly sized to meet demands.

However, it seems that satisfactory information concerning total daily amp-hour usage could be obtained with either system; a volt meter or a battery monitor.

Personally, I have used the volt meter and the solar panel's display to monitor our lead-acid batteries for several years.

While I have considered getting a battery monitor, and think it would be nice-to-have, I personally haven't considered it important enough to make the investment.

Two years ago when we were in Organ Pipe National Monument (no hookups) the second night we woke to a strange sounding furnance (think hemorrhaging) with the batteries at 11.4v. Got the batteries to 12.6 the next day with our rooftop and sure enough the same thing the next night, but about 11.2 v. Since we carry a battery charger the Rangers let me charge our two 6v 220 am AGM batteries at their office. By the 6th morning the batteries were at 10.2. Crown battery said we had a drain and to find the offending wires. I basically spent my whole time at Organ Pipe trying to find the culprit with my multimeter. Arrived in Phoenix and purchased a 12v battery for $100 from Costco and headed to Lost Dutchman SP. Everything ran fine: no voltage drop and the Costco battery recharged from the rooftop for our furnace by noon.

Two weeks after that first night at Organ Pipe Crown finally sent us new batteries under warranty. We had to drive from Lost Dutchman to the Crown distributor on the west side of the Phoenix area twice, about 160 miles round trip to deliver the offending batteries and then a couple of days later to pick up our new batteries. That's 320 miles folks!

First we installed a Victron BMV-712 monitor that keeps track of the ah's going out. Then we purchased a 100 watt Renogy portable panel hooked to a Victron 100/20 smart controller. This winter we parked in the shade at Chirichaua National Monument. Our rooftop 170 watt solar panel was essentially worthless, but the 100 watt portable charged our batteries with no problem. On the four night (of eight) I noticed we had around 12.2 volts the next morning. The next morning after that 12.2v night was 11.4v and the furnace was again hemorrhaging.

The 712 told us we're only using 20-25 ah's at night. The Victron smart solar controller tells us the daily charge history. Using the two together I instantly knew our second set of Crown batteries failed! I didn't have to run around with our multimeter to find a phantom drain! Can't do that with just a multimeter and volt meter.

I realize these were just abberations, but for us the ability to see a nights worth of use made the Victron products worthwhile for determining our failed batteries. We also camp as much as possible without hookups, so knowing how far down our batteries show on the 712 tells us if we're going to use or furnace or our Martin catalytic heater at night. Many others here use the BMV-712 to aid in battery monitoring.

We don't need or want a generator. I've seen the campground generator arguments.

Enjoy,

Perry

[Glenn Baglo]

Originally Posted by thrifty bill

Add a CPAP running on an inverter to your consumption and I think the outcome will be different.

I know it will be different. I just got one on a month trial. I know not to use the humidifier part to conserve power, but being a mouth breather, I might have to get a full mask. Any other suggestions welcome.

[Civilguy]

We've not spent the night in our trailer at 15 degrees, with or without hookups, so I can't speak to the particulars there.

Our 2012 Casita had the Suburban NT-16SEQ 16,000-btu furnace w/ DSI ignition. It draws 2.8 amps at 12VDC per the service manual. So, 10 hours of runtime equates to some 28 amp-hours.

The Casita also had an Interstate Deep Cycle SRM-27 battery rated by the manufacturer at 88 amp-hours, which would equate to supplying about 44 usable amp-hours.

I once ran down a little "wheelchair" battery in our teardrop trailer when we ran a 3-speed Fantastic Fan overnight. It was a Werker WKDC12-35J 12V 35Ah Deep Cycle AGM Battery.

That's when I first realized how high the current draw was on roof fans. The old three-speed Fantastic Fans drew 1.3 / 1.9 / 2.8 amps on low / medium / high. I later learned through the forums that the propane furnace fans also draw several amps, which is why I mentioned them in post #7.

Apparently, standard AGM batteries be drawn down to 30% of their rated capacity and still provide the same amount of cycles as a flooded deep-cycle battery drawn down to 50% of capacity.

So, 70% of the 35 AH battery in the teardrop trailer equated to about 25 amp-hours. However, in that case it was all the little wheelchair battery had to offer.

CPAP machines apparently draw 30 to 60 watts, which is 2.5 to 5 amps at 12 volts. 12 VDC to 120 VAC inverters will use additional energy in the process of converting the voltage, so finding a CPAP machine that works directly on 12 VDC would be desirable.

So, a "standard" Casita battery's 44 amp-hour usable capacity would seem to offer just enough to get by for a night if the CPAP's power requirement is at the lower end of the above range, the furnace is not running continuously, and other electrical loads are limited to LED lighting and a bit of water pumping.

Recharging phones and electronics are minor loads that would probably also be okay, but would best be done in the tow vehicle while driving.

[Lynn Eberhardt]

Mike summed it up very nicely. Know what your load demands are, do a little simple math, and check your battery voltage in the morning, with loads off. If you're at or above 50% in the morning, your system is keeping up. Make sure your wiring and tow vehicle can deliver between 13.5 and 14 volts to the trailer while driving.

I keep a battery voltage chart and a list of my usual loads handy for reference. It's good to have that info before starting an extended trip.

[WaltP]

Perry
Seems like you've had everything go wrong that can,but at least you know exactly how things happened and can take corrective action.

BTW, How did you like Chiricahua NM? I camped there Summer of '19 and think it rivals some of the best in Utah, just smaller. I'll sure use it again, any time I'm in that area.
Not too far from there is Cochise Stronghold, a veritable hidden gem of a NFS campground. Small, about a dozen campsites, no hookups, but a nicely maintained toilet building, nice trails and a gorgeous setting. The road in is a bit rough in wet weather, but otherwise not bad. Very worth it. Best to check it out with the ranger station first.

Walt

[Ronald W Stone]

I have two volt meters on attached to the battery and one connected to 12v outlet in my Scamp. The meter will show 12.8 on outside battery and 11.6 inside with everything of in the trailer. When I try to use the propane heater it will hardly work: slow fan and sometimes will not light. Why the voltage difference?

[Perryb67]

Originally Posted by WaltP

Perry
Seems like you've had everything go wrong that can,but at least you know exactly how things happened and can take corrective action.

BTW, How did you like Chiricahua NM? I camped there Summer of '19 and think it rivals some of the best in Utah, just smaller. I'll sure use it again, any time I'm in that area.
Not too far from there is Cochise Stronghold, a veritable hidden gem of a NFS campground. Small, about a dozen campsites, no hookups, but a nicely maintained toilet building, nice trails and a gorgeous setting. The road in is a bit rough in wet weather, but otherwise not bad. Very worth it. Best to check it out with the ranger station first.

Walt

Hi Walt!

Six months of the year our Escape sits in our lot in the local campground, next to the daily rentals. We've seen just about everything. My favorite is the guy who just pulled his brand new Jayco off the lot in Rochester and pulled it 45 miles to Lanesboro. Much screaming and swearing was heard three lots from ours. Turns out his kitchen cabinets fell off, ruining his sink, faucet, countertop, and floor, with oils from broken bottles running where they could, including on the new carpet. Of course I had no suggestions for the poor man, nor was this the time for suggestions. His wife was to meet him after work. Needless to say he was gone in an hour.

Like has been said here before, campers are nothing but cheaply built homes traveling down the road like a rolling volcano.

This was our fourth time in Chiricahua NM. We're avid hikers and love staying there. We call Chiricahua a 7 night, six day stay. You'd better have a portable with long wires to get solar since most sites are in the shade.

Cochise Stronghold is now creating more campgrounds on the way in, think BLM with only rock firepits. I'm guessing 20-30 new sites. The new campground roads are rough and there will not be much road improvement. Currently those campgrounds are free. We stayed there three nights watching our new SiO2 batteries eat roughly 24 ah's at night (according to our 712 battery monitor). We found a fantastic site, but the 170 watt panel was in the shade, so had only our 100 watt portable panel, but it easily filled the new batteries every day. Cochise is a three night, two day campground. We'll be there again next winter.

Enjoy,

Perry

[Jon Vermilye]

Originally Posted by Ronald W Stone

I have two volt meters on attached to the battery and one connected to 12v outlet in my Scamp. The meter will show 12.8 on outside battery and 11.6 inside with everything of in the trailer. When I try to use the propane heater it will hardly work: slow fan and sometimes will not light. Why the voltage difference?

If the battery volt meter stays at or near 12.8V with the furnace running & the inside is dropping to 11.6V, you either have a bad connection or undersized wiring. Typical locations for bad connections are the battery connections, the fuse block, or the connection(s) at the converter.

If you have a multimeter, with a load (such as the furnace) on the system, check the voltage across each connection. It should be 0 or a very small number. If you find where the drop is taking place, tighten or replace the connectors. You can also sometimes do this by feel - dropping a volt or so across a connector will usually result in heating.

[Gerry]

Wife and I took this cross country trip 2 years ago and with as everyone else says, leave anything that take electricity to create heat home. It's a battery killer.
We have a 100 W solar panel we put out when stationary and when driving our Tug charges the 2 Marine grade Batteries.
This gave us enough power to have lights in the evening for reading, run the water pump for showers, and small fan for those hot nights.
Stayed lot's of single nights when on the road at Wal*Marts.
On our 4 month journey we stayed at only a handful of campgrounds that had electric hook ups.
Used Propane for cooking either in camper or on camp stove at rest areas. Had Fridge on propane.

[Jon in AZ]

Things like toaster ovens , microwaves, and electric coffee makers are not suited for boondocking (backcountry or back parking lot), at least not without some very expensive electrical system upgrades. You can bring them along for the times you’re in a campsite with power, but only if you think that will happen often enough to be worth carting them around for 6000+ miles. Remember in the summer there may be times when you really need A/C to sleep at night. That always means a site with hookups. Be prepared to be flexible.

You’ll want to adapt your food preparation to use propane. It’s amazing what you can reheat in a simple frying pan. Pizza or pasta with sauce heats quickly with little loss of quality. We like to chop up leftover grilled meat and veggies, sauté lightly, and wrap in tortillas or just eat out of a bowl. Alternatives include steaming, boil bags, makeshift double boiler, or a grill (charcoal or propane). I’ve never done it but there are camp ovens that sit on a propane burner. Coffee can be pour-over, French press, Aeropress, percolator, or even cowboy style (I like pour-over). It’s just a matter of adjusting your meal planning.

Reserve limited battery power for essential trailer functions: lights, water pump, roof vent, fridge control panel, possibly occasional furnace use (it gets surprisingly cold at high elevations in early summer). Try to do most of your electronics charging in the car as you drive. Verify that your tow vehicle is putting out sufficient voltage through the charge line to fully recharge your trailer battery during a day’s drive. Make sure your trailer power center has up-to-date charging circuitry.

Consider breaking up a longer trip with 2-3 night stays in a campground with hookups every week to 10 days. A rest from driving is good to recharge your body, and you can use those appliances, run A/C, and otherwise take a break from “roughing it.”

[Perryb67]

Originally Posted by Jon in AZ

Things like toaster ovens , microwaves, and electric coffee makers are not suited for boondocking (backcountry or back parking lot), at least not without some very expensive electrical system upgrades. You can bring them along for the times you’re in a campsite with power, but only if you think that will happen often enough to be worth carting them around for 6000+ miles. Remember in the summer there may be times when you really need A/C to sleep at night. That absolutely means a site with hookups. Be prepared to be flexible.

You’ll want to adapt your food preparation to use propane. It’s amazing what you can reheat in a simple frying pan. Pizza and pasta with sauce is wonderful. We like to chop up leftover grilled meat and veggies, sauté lightly, and wrap in tortillas or just eat out of a bowl. Alternatives include steaming, boil bags, or makeshift double boiler. I’ve never done it but there are camp ovens that sit on a propane burner. Coffee can be pour-over, French press, Aeropress, percolator, or even cowboy style (I like pour-over). It’s just a matter of adjusting your meal planning.

Reserve limited battery power for the basics: lights, water pump, roof vent, possibly occasional furnace use (it gets surprisingly cold at high elevations in early summer). Try to do most of your electronics charging in the car as you drive. Verify that your tow vehicle is putting out sufficient voltage through the charge line to full recharge your trailer battery during a day’s drive.

Consider breaking up a longer trip with 2-3 night stays in a campground with power every week to 10 days. A rest from driving is good to recharge, and you can use those appliances, run A/C, and otherwise take a break from “roughing it.”

Excellent write-up Jon!

Aside from the smallest toaster we could find (when we have hookups), we carry no other 110 appliances. Terry bakes bread, cake, and makes pizza in our portable Weber grill (we don't have, nor want, an oven). We charge our e-bike and computer batteries driving down the highway, and have been using a Melita pour-over coffee system for decades.

Enjoy,

Perry

[Lynn Eberhardt]

People used heat to cook food for centuries before microwave ovens came along. Going back to that can be part of the camping adventure. A buttered frying pan even makes decent toast. Have fun with your creativity.

[JMolak]

Considering that you are going to Cali. it might not be a bad idea to get used to not having any power Actually a 2000 watt inverter generator will do what you need, they will usually run about 6-8 hrs on a tank of fuel (aprox. 1 gallon) Most are really quiet and reasonably priced. Have a safe trip!

[RockyBob]

I wouldn't depend on tow vehicle (TV) charging the trailer battery effectively. There's been considerable discussion about this. The problem is the TV alternator output is driven by the needs of the TV battery, and since the TV battery is likely always near full charge the alternator voltage will be low, maybe 13.6 volts. With typical voltage drop between the TV battery and the trailer battery (0.5 to 1 volt?) the voltage at the trailer battery will not result in any charging. There are 12 volt-to-12 volt chargers available just for this problem. They take low voltage (around 12 volts) and step it up to the 14 or so volts that a depleted trailer battery would need to recharge. Available on line.

[Wynn]

Some walmarts are putting up signs for no overnite parking. I live in the ST Louis area and travel to colorado and florida yearly, i stop at Loves or Flying J travel stops, i have always backed in with the 18 wheelers and never had any problem. I suggest finding one before 5 pm due to trucks having to get off the road after driving so many hours. In the summer i bring my 30a generator for ac. You can check ahead with google maps, satelight and see the layout and food each travel stop has as a side restaurant. I like ones with arbys or chicken.

As far as battery, in my F150, i hooked up a 400watt inverter back to the battery with #10 wire so we can setup the crock pot for the day and have a hot dinner when we stop for the nite. Many great things you can do with a crock pot.
I also have a non sign wave 20amp i clamp on to the battery of the truck with 2 #6 wires fixed to the battery and ready to hook to the inverter if i need it. Short big awg is required for 20 amp as it pulls 200 amps at 12vdc. I have the truck idle. I use it for toaster oven, harbor freight extendable tree limb cutter for fire wood or my small pancake compressor . Great deals on 200-435 watt solar panels in AZ and dallas on ebay, new panels free pickup. 435 watt mono panel is about $145, works well in slight shade. Many good deals out there! I am heading to az in april for mine. Check out cheaprvliving with bob wells for more great boondocking and bom sites, free camping, ect. Hope you travels are great and safe!

[Raspy]

Originally Posted by Civilguy

As John mentioned, the accuracy of readings taken with the $12.99 voltage meter could benefit from shutting off loads and waiting a few minutes to see if there's any change in the displayed voltage.

If the Casita has a single lead-acid 12-volt battery, as most do, then a volt meter and a small notebook can provide plenty of information accurate enough to protect the battery on a cross-country trip.

A Victron battery monitor at $206, plus any associated materials and labor costs for installation, might be a good investment for collecting more data. Or, it might not.

It would certainly be wise to gather information on total daily power usage to guide any significant investment in batteries and solar capacity so that the system could be properly sized to meet demands.

However, it seems that satisfactory information concerning total daily amp-hour usage could be obtained with either system; a volt meter or a battery monitor.

Personally, I have used the volt meter and the solar panel's display to monitor our lead-acid batteries for several years.

While I have considered getting a battery monitor, and think it would be nice-to-have, I personally haven't considered it important enough to make the investment.

This is exactly what I have been doing for years. It takes a bit more thought to understand what a volt meter is telling you, but once used to it, it has all you need to know. They are ridiculously cheap and installation only requires plugging it into the socket. Sometimes simple and cheap look very attractive.

[THene1713]

First, make sure ALL Lighting is converted to LED= 90% power reduction