Non-electric campsite, battery question

[jhawk]

I have 2008 Flagstaff 206 LTD, set up with a single deep cycle battery. We are going to take the camper out next weekend and the campsite may not have electric. The temp is supposed to be in the 40's at night so we will probably use the furnace, which also means the electric blower for the furnace. I have a spare deep cycle battery that I use for my trolling motor and was wondering if I could just hook it up to the existing camper battery with jumper cables to extend the overall battery life.
Also, if the battery on the camper does go dead will hooking up to my tow vehicle allow me to still use the electric power lift at the end of the weekend?

Thanks,

John

[WrongWayRandall]

You likely would do better to keep an eye on the battery charge level and swap batteries when the first gets to 11.8v or so (I'd go no lower than about 11.5v at most if it a true deep cycle and not a dual purpose 'deep cycle' marine battery.) To connect them at the same time requires heavy gauge wiring and it sounds like this is a one time thing.

As for a dead battery condition, hook up the 7-pin to the trailer and then you can pull off the tow vehicle battery to run the jack. That little draw should not be a problem (but if you are concerned, just start the tow vehicle before running the jack.)

If you regularly use up the capacity of your existing deep cycle you might consider getting a second of the same battery and then wiring them 'permanently' together. To do this you need to read up on the difference between 'in series' and 'in parallel' wiring of batteries.

By the way, you'll want to keep from pulling even a deep cycle down really far as it will slowly but surely reduce the capacity and lifespan of any battery to be too deeply discharged. Consult the battery manufacturer on that model of battery for their usage chart - you'll see that you can get more cycles the less discharged each cycle is.

- Randy

[f5moab]

If you mean automotive jumper cables, I would see no problem, even the cheapest should be at least 10 gauge and my batteries, as installed by the dealer are wired with 12 gauge wire. But without a inline 30 amp fuse, not sure if I would trust it connected while I was asleep.

However, I agree with swapping out the batteries, I have been told it is not recommended to connect two different type so batteries in parallel.

If it was me and to save the battery due to excessive drop of voltage (as explained above) I would swap the fresh battery at bedtime. You don't want to run one down all the way while sleeping and possibly destroy the battery.

[camaraderie]

You most definitely do not want to let either battery go below 12.0V. Unless you want to buy new ones sooner rather than later.
You should NOT hook them up together...hot swap them when one gets to 12.0
So add my ditto to the others... And if you plan to do this often...get TRUE deep cycle batts and hook em up together!

[Still Kickin]

Originally Posted by WrongWayRandall

You likely would do better to keep an eye on the battery charge level and swap batteries when the first gets to 11.8v or so (I'd go no lower than about 11.5v at most if it a true deep cycle and not a dual purpose 'deep cycle' marine battery.) To connect them at the same time requires heavy gauge wiring and it sounds like this is a one time thing.

As for a dead battery condition, hook up the 7-pin to the trailer and then you can pull off the tow vehicle battery to run the jack. That little draw should not be a problem (but if you are concerned, just start the tow vehicle before running the jack.)

If you regularly use up the capacity of your existing deep cycle you might consider getting a second of the same battery and then wiring them 'permanently' together. To do this you need to read up on the difference between 'in series' and 'in parallel' wiring of batteries.

By the way, you'll want to keep from pulling even a deep cycle down really far as it will slowly but surely reduce the capacity and lifespan of any battery to be too deeply discharged. Consult the battery manufacturer on that model of battery for their usage chart - you'll see that you can get more cycles the less discharged each cycle is.

- Randy

At 11.5 V, your battery is pretty much done. Repeated discharges to that level will destroy your deep cycle battery in short order. Here are two things that will help you navigate your battery useage, and status concerns.

1. Chart indicating state of charge of the battery (s) 12 Volt battery state of charge chart and info (PDF))
2. Battery status tester for cigarette socket. car cigarette lighter voltmeter Reviews - Online Shopping Reviews on car cigarette lighter voltmeter for | Aliexpress.com

[jhawk]

we are going to camp this friday and saturday night so if all I have running on the battery is the fan for the furnace will a single size 24 deep cycle last both nights? one night? or die sometime the first night?

[Herk7769]

Originally Posted by jhawk

we are going to camp this friday and saturday night so if all I have running on the battery is the fan for the furnace will a single size 24 deep cycle last both nights? one night? or die sometime the first night?

Obviously, how cold it is will determine how long a battery will last without recharging. The furnace is the biggest DC draw in the camper.

While the water pump (as an appliance) is number two, in reality the lights come next. EACH incandescent bulb draws 1.2 amps. So a 2 bulb light draws 2.4 amps.

The state of the battery(s) at sundown and how often the furnace runs will determine if they last through the night.

Best to have a small generator and a dedicated battery charger along. Stop at Harbor freight and buy a 12 volt battery charger and a 900 watt gas generator. Plug the charger into that loud beast and charge up your battery for an hour or two. Do not use the on board converter as it will take way too long.

900 Peak/800 Running Watts, 2 HP (63cc) Gas Generator

2/6 Amp, 6/12V Manual Charger

[mlong]

Get one of these http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1. I have 2 of them. We are camping for 4 days over Memorial Day weekend. We booked late so we had to settle for a non-electric site. zI used one of these last year when we camped in Assateaque State Park with our pop up. We did not run the heater. Just lights. I used this every day to make sure the battery stayed charged. I took the battery & battery box from the pop up and I will use these on the new camper. Since I have 2 batteries I decided to have to solar chargers. They do not have charge contollers so you need to keep an eye on them. I had no problems last year.

[WrongWayRandall]

Originally Posted by Still Kickin

At 11.5 V, your battery is pretty much done. Repeated discharges to that level will destroy your deep cycle battery in short order. Here are two things that will help you navigate your battery useage, and status concerns.

The lowest discharge varies depending on the individual battery - some of mine came with a chart from the manufacturer stating that 11.5 is the lowest acceptable discharge level (true deep cycle, and damned expensive at the time.) Personally, I will never go below 12.0v on any battery, but that's just me and I have not done extensive testing to verify that the manufacturer is correct.

As I stated in my original post, I agree with you that the more deeply any battery is discharged the poorer it will perform and the shorter it's lifespan will be.

- Randy

[camaraderie]

Originally Posted by WrongWayRandall

The lowest discharge varies depending on the individual battery - some of mine came with a chart from the manufacturer stating that 11.5 is the lowest acceptable discharge level (true deep cycle, and damned expensive at the time.) Personally, I will never go below 12.0v on any battery, but that's just me and I have not done extensive testing to verify that the manufacturer is correct.

As I stated in my original post, I agree with you that the more deeply any battery is discharged the poorer it will perform and the shorter it's lifespan will be.

- Randy

11.5% is 80% discharge. This will cut your cycles IN HALF from a 50% discharge regardless of mfr. of wet cell batteries.

[f5moab]

Here's a chart that shows discharge levels as percentage...

[WrongWayRandall]

Originally Posted by camaraderie

11.5% is 80% discharge. This will cut your cycles IN HALF from a 50% discharge regardless of mfr. of wet cell batteries.

No need to yell. I'll bow out of the discussion since posts are not being read in their entirety...

- Randy

[jhawk]

Sounds like if we can't get an electric site I'm taking my long johns to sleep in. I don't want to kill both of my batteries before summer even gets here! Thanks for the info, I didn't realize how big a drain the fan would be.

[mlong]

I think the issue is how much it runs. Ours ran a lot this past weekend when temps got down in the 30's overnight. Of course it did not help the first night when my son woke up at 3 am and asked why one of the roof vents was opened! I forgot to close it after installing the roof vent covers. Even after closing it the furnace ran a lot.

[katkt]

I remember camping in a tent with no heat. Get into bed quick. Get out of bed quick.
I remember camping in a popup, with a heater. Run the heater just before bed, so you didn't have to race to the covers. Turn it off during the night...because your in bed covered up. Somebody is the designated "get up and turn the heat on" in the morning person, to warm the camper up so everybody else can get up nice and toasty.
Is running it all night long needed. Every person in the camper is cranking out 98 degrees. A couple of extra blankets? Sleeping bags? Socks

Just a thought about roof vents. It's a good idea to crack one open a bit to let some of the humidity out, if you don't run the heat all night long. Otherwise, it'll collect on the ceiling.

[pgandw]

Originally Posted by jhawk

Sounds like if we can't get an electric site I'm taking my long johns to sleep in. I don't want to kill both of my batteries before summer even gets here! Thanks for the info, I didn't realize how big a drain the fan would be.

We would dry camp for 8-10 days each year at Lake Tahoe (6000ft elevation) in our PUP (single battery). We used sleeping bags, but still needed to keep the PUP thermostat at 50 degrees for reasonable comfort. Some years, we needed to run the heater at least half the nights. You could tell by the lights that our battery was being discharged more than I would like it to be. It became appararent that the real limit on our endurance (for our style of camping) was the battery.

Things that are really worth doing:

1) Replace any lights that get used frequently with LEDs. I hated being the light police (to save the battery). By using LEDs, the lights are no longer a significant load. LED flashlights and/or headlamps for everybody, and a gas lantern at the picnic table further reduce battery use.

2) On my first PUP (didn't have a hot water heater), I replaced a broken faucet with a gooseneck, and replaced the electric pump with a nice foot pump for sailboat galleys. I like that arrangement much better, and could access my water supply regardless of battery charge. It would be a little trickier to redo the plumbing to keep water in a hot water heater and/or pressurize a shower - probably need electric there. But foot pumps for the galley are so nice....and they keep the gray water bucket from filling up so fast.

3) Again, the simplest alternative if the battery bank is not sufficient to run the heater as desired is to use a portable catalytic heater. It's not as convenient as a large battery bank, but setting up and monitoring solar panels or carrying and hooking up generators, or just plain monitoring battery charge is not all that convenient, either.

I've become a firm believer in keeping my camping just as simple as I can with a reasonable comfort level. The simpler the systems are, the more time spent enjoying the outdoors instead of setting up/packing up and systems monitoring.

Fred W

[mlong]

Camp with my wife! She's cold in 70 degree weather. At home she sleeps with a heated blanket, fleece pajamas & 2 heavy blankets. Still complains she's cold.

No heat on in the camper!

[Witch Doctor]

Just take full charged battery with you, if you need to change them out just install the second battery. If you hook it to the low battery it will try and charge it. Not a good idea. CW has some cheap flex solar charger on sale this week. But Hope you have sun if you go that way.

[camaraderie]

Originally Posted by WrongWayRandall

No need to yell. I'll bow out of the discussion since posts are not being read in their entirety...

- Randy

Sorry you interpreted that as yelling. It was meant to be emphasis for the OP not to go to 11.5
I read your post and felt the OP needed to understand just how damaging going to 11.5 is.