Battery Life on a trip

[Esther out east]

Hello All,
We are hoping to do a trip across the country (MA to CA) this summer. Even though COVID is improving & we will be vaccinated, we feel it would be best if we were self contained for most of the trip. That means we will be boondocking a lot of the way for 10-12 days (and then back again). We have a new battery for our 2006 Casita Spirit. Does anyone know how many days we can expect to go without plugging in? We have a solar panel that should help, too. We hope to do most of our cooking on a 2-burner gas stove. But we may heat up prepared meals in a toaster oven. We will also be running a C-pap machine at night.

Thanks for any help you can give.

[Glenn Baglo]

Leave the toaster oven at home unless you are going to plug in. Turn humidifier off in the CPAP. Solar and charge from vehicle when rolling should take care of your needs there and back.

[thrifty bill]

+1 Forget electric appliances, those are a non-starter, will eat the battery. Get a stove top percolator for coffee. Need about 200 watt solar unit (assumes you will stay put in one spot more than just one night). Prices have fallen, portable suitcase is a nice option. Vehicle charge efficiency depends on wire size. Go big.

Besides boondocking, lots of dry camping out west at some of the best National and State parks. And if you are trying to make really good time, some nights at Walmarts can be very efficient. Our route out west includes a night at the Columbia, MO Cracker Barrel and the Goodland, KS Walmart.

[AC0GV]

Originally Posted by Esther out east

Hello All,
We are hoping to do a trip across the country (MA to CA) this summer. Even though COVID is improving & we will be vaccinated, we feel it would be best if we were self contained for most of the trip. We will also be running a C-pap machine at night.Thanks for any help you can give.

Same question really. How big is your battery (gas tank)? What are your electrical loads (how fast do you drive)? How often are you recharging (stopping for gas)? If you are using a group 27 or larger battery, charging as you drive (properly wired 7 pin) and limit your use, one or two nights will be OK. If the tow vehicle fails to fully charge the battery, you will need a backup plan. I carry solar, a small generator, and camp at an electric camp site if I need air conditioning. My F150 never fully charges the batteries, and you only get HALF the rated amp hours from a lead acid battery if you want it to last.

[WaltP]

Considering all you have invested in your travel rig, the cost of a small (2000W) inverter generator would not be that much and would make your trip a lot less stressful. And then you could still take your toaster oven.

Walt

[Steve Outlaw]

Originally Posted by Esther out east

... Does anyone know how many days we can expect to go without plugging in? We have a solar panel that should help, too. We hope to do most of our cooking on a 2-burner gas stove. But we may heat up prepared meals in a toaster oven. We will also be running a C-pap machine at night.

Thanks for any help you can give.

I would not count on more than one night without recharging. I doubt your battery has more than 105 Amp hour capacity. That means you can only use about 50 amps out of it before you will start to damage it beyond repair. If you use more than that many amps every 24 hour period without recharging fully each time, your battery will do good to make it through the whole trip. I agree with Walt, a small generator will take all the worries away.

[Civilguy]

Originally Posted by Esther out east

Hello All,
We are hoping to do a trip across the country (MA to CA) this summer. Even though COVID is improving & we will be vaccinated, we feel it would be best if we were self contained for most of the trip. That means we will be boondocking a lot of the way for 10-12 days (and then back again). We have a new battery for our 2006 Casita Spirit. Does anyone know how many days we can expect to go without plugging in? We have a solar panel that should help, too. We hope to do most of our cooking on a 2-burner gas stove. But we may heat up prepared meals in a toaster oven. We will also be running a C-pap machine at night.

Thanks for any help you can give.

With a 7-pin connector, each day that you drive will allow the tow vehicle to top up the batteries. So, that will be helpful while you are traveling.

Change out the light bulbs out for LEDs if you have the old incandescent bulbs. Try to minimize the use of the roof fan and the furnace as the fans use a fair amount of energy. Also, if you have an electric tongue jack use the manual bypass if you are able.

Purchase a little voltage meter and make a habit of keeping an eye on it and jotting down the time and voltage readings occasionally. You really do not want to drop below 11.9 volts before recharging as the battery gets damaged below that voltage.

https://smile.amazon.com/gp/product/...J5XTHH78&psc=1

[rdickens]

Ester,

Does your CPAP run on 12v DC current?

You won't be able to run any 110v AC appliances unless you are are plugged into 110v "shore power", you are running a generator, or you have a fairly large "inverter" to change 12 DC into 110v AC.

With a sufficiently large battery + solar panel + higher-capacity inverter, you might be able to run LED lights, a CPAP, the top-mounted fan, and cellphone/tablet chargers. Most inexpensive inverters might have a really hard time providing enough 110v wattage to run a toaster oven ... just my guess?

Although it always seems like some folks are fascinated by FGRVs and might want to ask to see inside yours, if you are able to maintain "social distancing" and wear masks, you might do just fine at many state parks, COE campgrounds (corps of engineers campgrounds), and maybe even some commercial campgrounds?

Good luck to you!

Ray

[John in Santa Cruz]

typical toaster oven is 1200-1500 watts, which is 100 to 125 amps at 12V... so 6 minutes is 10-12 amp*hours at 12V. if your trailer has a single battery, thats probably around 105 amp*hour rating, but you never want to use more than 50% of a lead acid battery if you want it to last a few years, so you've got maybe 50AH usable, so if you're not using ANY other power, you'll get 4-5 6 minute cycles from the toaster oven.

[John in Santa Cruz]

Originally Posted by Civilguy

Purchase a little voltage meter and make a habit of keeping an eye on it and jotting down the time and voltage readings occasionally. You really do not want to drop below 11.9 volts before recharging as the battery gets damaged below that voltage.

https://smile.amazon.com/gp/product/...J5XTHH78&psc=1

be sure to take that reading when all loads have been shut off for a few minutes to get a realistic battery state.

[Esther out east]

Thanks,

We have a 12 volt battery. All we really need is electric for the CPAP (we have a converter for that), the fan & charging cell phones. We have all LED lights inside. I expect we will be driving 6-7 hrs/day so the battery should recharge, right? We have a Pathfinder.

I am hoping if we stay a few days somewhere, we will have hookups. And I am very hopeful that by mid-July life should be a bit freer. I will start looking at our route and see about reservations at state/national parks. My guess is that this year is going to be very competitive, since many stayed home last year.

I love the idea of a voltage meter and a small generator. I'll look into that. My husband is a foody and loves to cook and doesn't think camping should be a compromise. I have to admit, I don't mind eating his creations!

Thank you all for wisdom. It is so appreciated.

[Esther out east]

Thank you. Great information. I am on it. I love the idea of a voltage meter.

[gordon2]

Originally Posted by Esther out east

Thank you. Great information. I am on it. I love the idea of a voltage meter.

With a thick Italian mafioso accent*, I say... "Fer get about it.."
...the voltage meter that is.

Get a battery monitor that uses a shunt to measure and track current into and out of the battery.
You will see your power use in real time, and also over time. You will know how charged or discharged the battery is. You will quickly find out if you need to upgrade your power supply system or if you can conserve power use to extend your time off grid.
Victron is the best budget choice. Professional or skilled and knowledgeable DIY installer required.
------------
* No offense intended to my Italian brothers and sisters except for those very few in the other "family."

[John in Santa Cruz]

I just installed a Victron Smart Shunt on my dual GC2 (2 x 6V golf cart batt) setup on my E21.

pretty much just flipped the battery isolate switch, opened the bench, opened the battery box, disconnected hte ground wire from the negative terminal of the combined battery, attached a 2AWG 2 foot ground cable to the battery negative terminal, pulled the original ground cable out of the battey box, routed those two cables to where I screwed the smart shunt down, ran the two skinny red wires the smartshunt came with to the battery + terminal, and the between-battery bridge, and plugged those into the smartshunt, then linked it up using Bluetooth with the Victron Connect app runnign on my phone.....



if I'd gotten the Victron 712 display thingie, it comes with a similar shunt that you wire up the same way, plus connect a RJ11 telephone wire from the shunt to the 712 display panel that you mount where convenient.

[WaltP]

Yeah. I've done the same except since my batteries are mounted outside on the rear bumper the rewiring was more of a pita.
But what's your point? All that will do is show him why his plan isn't working.[emoji3061]
Walt

[Glenn Baglo]

SmartShunt should raise your blood pressure as you watch your battery performance. Best bring along a blood pressure monitor.

[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.

[Raz]

I've travelled across country numerous times with a group 24 battery ( small) and a $15 voltmeter. My tow vehicle charges my battery during the day. With LED lights, occasional water pump use, and a fan on low, l can easily go two nights without recharging. I have an AM/FM/weather radio that runs all season on 4 D cells and a tablet that I charge in the tow. With a 60 watt solar panel, I can stay as long as I please provided the sun is out.

Anything that uses electricity to make heat; a toaster, coffee pot, etc., is not practical without a 120 volt source. A generator works but only if you are allowed to use it. Many campgrounds have generator restrictions, especially at night.

Does your C-pap machine run on its own battery and if so, will it run all night? Can it be recharged by the tow vehicle? If it requires 120 volts, then a generator or campgrounds with power are your best option.

Finally there are folks who have turned their trailer electrical system into a hobby. They have become experts. Unfortunately they think everyone should do the same and are quick to give a beginner the impression you need equipment you don't. I'm a retired electrical engineer and my $15 voltmeter has served me well for years. Safe travels. Make lots of memories.

[ThomasC]

No one "unless I missed it" has mentioned heating the RV. It has been my experience that it will take a fully charged battery to make it through one night. So the battery needs to be fully recharged each day and without a Battery to Battery charger that will not happen. Tow vehicles do not fully charge a battery off the 7 pin connector.

[WaltP]

Originally Posted by ThomasC

No one "unless I missed it" has mentioned heating the RV. It has been my experience that it will take a fully charged battery to make it through one night. So the battery needs to be fully recharged each day and without a Battery to Battery charger that will not happen. Tow vehicles do not fully charge a battery off the 7 pin connector.

I don't know what you mean by a 'battery to battery charger', but a 100 watt solar panel will fully charge it on most days and a small inverter charger will do it it every day if you have fuel for it.
And as far as heating goes, unless I am dealing with temps below 20 deg F I only need the heater for awhile before bedtime and to take the chill off in the morning. With the standard propane furnace that's not overly demanding on the battery. And if anyone has ever died from CO from the standard, built in propane furnaces I think it would be all over the RV forums in a NY minute. They are as safe as gas home appliances.

Walt