| |
Subject |
Author |
Date Posted |
Forum
|
 |
RE: How long should a battery last?
If he's boondocking the way I think of boondocking, he won't be in a campground with rules but rather a dispersed spot with only the neighbors he traveled with. I do realize there are campgrounds without hookups so valid points on generator hours/rules.
My initial generator set up will be to run it during daylight hours and evening till bed. Only shut it off when sleeping. However, eventually, I would like to only need a few hours of run time a day.
Two ways to reduce run time.
1. increase battery bank capacity.
or (better)
2. add a solar panel charging system.
or (best)
Do both 1 and 2
Have fun!
I have a small solar panel on the roof.
By the time I am done, I want to have enough that sitting there, regardless of weather, with everything "shut off" the panel is enough. Then I want to get to the point where lights, furnace and fridge is on and the solar panels can keep up in fall. The goal is the only reason for the generator is to run the AC in the middle of the summer heat.
|
swimmer_spe
|
03/27/23 06:44pm |
Tech Issues
|
|
RE: How long should a battery last?
No matter what you see on TV you can't have all of the conveniences of home in a TT that only has an itty bitty group 24 battery bank.
When it comes to dry camping battery bank capacity & fresh water capacity is King. Sure, one person can get by one night with a single group 24 being very frugal with the power use. Add another person with the additional use of everything 12V & that group 24 is dead very quickly.
For 13 years of our boating days we were out every weekend, 2 nights, May to October. No generator. No solar onboard. Always 'on the hook' anchored someplace. The battery bank consisted of two group 31 gel cells linked through a battery switch enabling the use of battery #1, battery #2, or both combined.
We had to be very conscious of power use. Enough power had to be there to start the diesel when it was time to move, hence the battery switch to isolate one of the batteries & use the other as the 'house' battery on anchor.
Unfortunately RVs are not setup that way, unless their owners 'marinize' their wiring & install a battery selector switch. A relatively inexpensive & simple thing to do.
With a setup such as this, if you leave something on & discharge one battery you have the other to switch to. It is always good to pack as much battery power as possible. You never know when you will really need it.
Eventually, I want to have all the comforts of full hook ups while boondocking. I know that is going to take a lot more components, but it is my plan to do over the next few years, starting with my own quiet generator. I know replacing the batteries will also be needed. This was about 1 weekend without that.
|
swimmer_spe
|
03/27/23 04:37pm |
Tech Issues
|
|
RE: How long should a battery last?
If he's boondocking the way I think of boondocking, he won't be in a campground with rules but rather a dispersed spot with only the neighbors he traveled with. I do realize there are campgrounds without hookups so valid points on generator hours/rules.
My initial generator set up will be to run it during daylight hours and evening till bed. Only shut it off when sleeping. However, eventually, I would like to only need a few hours of run time a day.
|
swimmer_spe
|
03/27/23 04:24pm |
Tech Issues
|
|
RE: How long should a battery last?
I have plans of getting a generator in a year or so, so it is not that I bought the wrong equipment, but that I am not yet prepared for what eventually I will be for.
You have other issues besides just getting a generator. First you need a battery bank of appropriate size for your power consumption. Next besides just buying a generator, do you have any idea of how much generator time is needed to replenish and completely charge your batteries? You are going to have to let that generator run for hours assuming you are allowed to do that where you are staying. For example in many National Parks some campgrounds do not allow generators. In others use is limited to a few hours a day corresponding to meal times. If you do stay where generator use is not restricted, you might be subject to listening to a campground full of noisy generators.
Or are you just willing to limit almost all of your camping to RV parks with hook ups?
Do you really think you bought the right equipment? Does it work for you now? Will it be what you want later on? If so, then great.
All of that is why I am not buying one right now. I need to figure out a lot more than just run the generator. I know it is not as simple as run the generator and you are good.
|
swimmer_spe
|
03/27/23 04:20pm |
Tech Issues
|
|
RE: How long should a battery last?
This thread reminds me of a friend who bought an EV and wanted to take a road trip. In theory they should be able to drive a couple hundred miles before charging so not much of a road trip. To make it worse they wanted to travel in the winter months. The batteries are less efficient in the cold and battery power is needed to heat the interior of the car. So no road trips in that car.
They had great intentions. First they thought they would save on operating costs. We live in an area where electric rates are way, way over the national average so that is not going to happen. Next they thought they were helping to keep pollution down and doing their part to reduce global warming. That electric power did not come free. It comes from a power plant burning natural gas or an older plant burning oil.
Sometimes there just isn't a good fix after buying the wrong thing.
I have plans of getting a generator in a year or so, so it is not that I bought the wrong equipment, but that I am not yet prepared for what eventually I will be for.
|
swimmer_spe
|
03/26/23 08:34pm |
Tech Issues
|
|
RE: How long should a battery last?
For two days I would just freeze ice jugs and put several in the freezer section and several in the refer section. You start with fully charged batteries frozen jugs, and cold food, while driving you are powering your refer from the alternator. Once the ice jugs melts after several days use the ones in the freezer section. If you use your battery power just for water pump and a few lights you should be fine for several days. When it comes time to replace the battery, replace it with 2 GC batteries wired in series and you will last a week and still be at 50% plus SOC, with your electric refer off.
I love that idea! Realistically, it is just me using it, so not much in it and as I am not a kid, it won't get opened and closed constantly.
|
swimmer_spe
|
03/24/23 08:05pm |
Tech Issues
|
|
RE: How long should a battery last?
...They don't install absorption fridges anymore.
That's what I've gathered from the forums. Followed by grumpy scoffs from boondockers! LOL You mentioned that you're in a one-off boondock situation so not worth investing in any more gear. So you can fire up your tow vehicle and plug in the trailer via 7-pin to get some juice into the battery. Without upgrades to that wire path, it will not provide a whole lot of current for charging. But it is equipment you already have.
How long should I run it for if the battery goes down below 12V?
I do boondock with others, but they have a generator. That generator is not mine, and is not available for this one off time. I do plan to get a generator, but not likely for this trip.
|
swimmer_spe
|
03/24/23 08:03pm |
Tech Issues
|
|
RE: How long should a battery last?
That's about right. You should not be running an electric fridge on that battery. The battery will be shot before the end of the year.
We have no choice as it is a 12v/120v fridge. I typically do not use it on 12v except for while driving.
Based on prior threads you have posted, I believe you have a 12v DC fridge (no propane option).
When on shore power, your converter takes the 120v AC and converts it to 12v DC to power the fridge and other DC loads.
If it's the 12v DC fridge I think it is, it draws around 50w when running (approx 4amps). Assuming it's running approximately 50% of the time, that's 24hr * 50% * 4amp ~ 48amp-hr for a 24hr day (in hot weather it will run more and use more amp-hr).
Of course, there are probably another 10-20amp-hr from lights and other 12v devices so call it 60amp-hr.
A single 12v dual purpose battery is likely around 70-100amp-hr depending on specifics but you really don't want to use more than half of that (35-50amp-hr) or the battery will have a really short lifespan. As you can see, you are running that battery near dead boondocking.
Options:
- Get a second battery and wire in parallel to double your available amp-hr. This will buy you a day. If you want a weekend, you likely need more batteries (6v golf cart batteries would be a better option as they hold more amp-hr for a given size)
- Get a small generator and run it once or twice a day to keep the batteries charged (a single battery will be marginal getting thru the night, so 2 batteries would be best).
- In a pinch, you could hook the trailer up to the truck and run the engine and the trailer plug will charge the batteries. Not a great option as it's very slow charging and you are putting wear & tear on an expensive piece of machinery.
- Stay in a park with electric hookups.
Thank you for the insight.
Since it will be a one off, I will lug the extra batteries around.
|
swimmer_spe
|
03/23/23 11:25am |
Tech Issues
|
|
RE: How long should a battery last?
If you want to know how long your battery should last you need to provide information on the refrigerator, make and model and/or operating amperage.
Without that information, I can confirm your experience as being typical for even a small 12v refrigerator. I have a very efficient, small (4 cuft) refrigerator. It pulls a bit over 3 amps and runs about 1/3 of the time in low/moderate temperatures. In the summer and if the door is opened frequently or warm drinks/food is put into it, the refrigerator will run almost constantly. So it will pull about about 25-70 AH/day. For even my small unit and with no other use of electricity, I would need 2 or 3 of your batteries to make it through a long weekend.
You really don't have a lot of good options. The most obvious would be to camp exclusively with electric hookups. Without hookups even an extra battery or two would not buy you more than a short camping trip.
Your next cheapest option would be to buy a generator. Unfortunately you will need to run it several hours a day to keep your batteries charged and in good condition. If you want to avoid that daily generator use, you will need to consider solar. You will still need the generator when days are short, you are camped in the woods, it is cloudy, etc.
Regardless of your choices you might want to scrap your existing battery. If you have run it down to 11.5 volts several times its life expectancy is short. Buy at least 2 good sized replacement batteries.
Here is a tale that might help you understand the mistake you made:
https://www.exploroz.com/members/145028.75/1/2009/queensland_adventures_winter_2008.aspx?p=%2fblogs%2fdefault.aspx
A few things:
1) where would I get the information needed to know how much the fridge would draw?
2)I have 2 other deep cell batteries that are good. Would that likely get me through a weekend with the information I have already spoke of?
3) If I boondock more often, I will be getting a generator.This is more of a one off situation.
|
swimmer_spe
|
03/22/23 06:46pm |
Tech Issues
|
|
RE: How long should a battery last?
You may need to get a generator for boondocking.
I don't boondock often enough to make it worth it.
|
swimmer_spe
|
03/22/23 06:13pm |
Tech Issues
|
|
RE: How long should a battery last?
Does the fridge have a propane option? If so you should use gas when boon docking. Will use very little battery to operate.
No, otherwise it wouldn't be a concern.
|
swimmer_spe
|
03/22/23 06:12pm |
Tech Issues
|
|
RE: How long should a battery last?
That's about right. You should not be running an electric fridge on that battery. The battery will be shot before the end of the year.
We have no choice as it is a 12v/120v fridge. I typically do not use it on 12v except for while driving.
If boondocking you'll have to run it on 12V, right? Is that how you're testing it during your 24hr test?
With a propane absorption fridge, a single group 24 would probably be be pretty low after a weekend of fridge and lights (also water pump and maybe fans). A 12V electric fridge would be a much larger load on the battery.
Last fall I turned the heat to room temperature and fridge on and in 24 hours, the battery dropped to around 11.5v. They don't install absorption fridges anymore.
|
swimmer_spe
|
03/22/23 06:11pm |
Tech Issues
|
|
RE: How long should a battery last?
Typical code 24 battery, how long should it last with lights and electric RV fridge? I am only getting about 24 hours before it gets under 11.5V. Also, would a battery shop have a way to properly test the battery to see if it is actually any good? Would an RV shop be able to properly test it?
A group 24 is around 70-75 amp hours and you can only use about `15 of them before it is run down. So not long
A pair of GC-2 (6 volt golf car in series) are 220 give or take a bit amp hours and you can use half. that's a lot more than one G-24
Brand new trailer with a new battery. I'd rather not need to change the battery out for a weekend of boondocking for a weekend every now and then. If I were doing it once a month or more, then, I would see the need.
|
swimmer_spe
|
03/22/23 04:32pm |
Tech Issues
|
|
RE: How long should a battery last?
You should use an electric site when camping. If you keep running the battery down you will have nothing working in your trailer.
That is my goal, an electric site. However, it would be nice to boon dock for a weekend without another battery or generator, or wall of solar panels.
|
swimmer_spe
|
03/22/23 04:28pm |
Tech Issues
|
|
RE: How long should a battery last?
That's about right. You should not be running an electric fridge on that battery. The battery will be shot before the end of the year.
We have no choice as it is a 12v/120v fridge. I typically do not use it on 12v except for while driving.
|
swimmer_spe
|
03/22/23 04:22pm |
Tech Issues
|
|
How long should a battery last?
Typical code 24 battery, how long should it last with lights and electric RV fridge? I am only getting about 24 hours before it gets under 11.5V. Also, would a battery shop have a way to properly test the battery to see if it is actually any good? Would an RV shop be able to properly test it?
|
swimmer_spe
|
03/22/23 04:04pm |
Tech Issues
|
|
RE: Solar power
OP here.
I plugged it back in. It rebounded to 11.9V
I now know.
Do you mean you were charging it? Or just measuring the voltage (at the battery posts would be preferred.
40% is a bit too low.
I was reading off my panel in the trailer. The rebound I am assuming was due to the solar panel. Not bad, but definitely not good.
I'm still not following.
- What did you plug in? If you mean shore power, that just means the charger (aka: converter) kicked on. In that case 11.9v is not indicative of the state of charge. In that case, the charger is likely trying to push somewhere north of 13v but the battery is sucking it up pulling the voltage down because the battery is dead. Using voltage to estimate state of charge only works if there is no charging or loads and the battery has been left to sit for a while.
- What were the sun conditions? Mid-day it might be the panel but same issue with it not being representative of the state of charge.
Shore power was disconnected for the test.
It dropped to 11.5v. I then checked it a few hours later and the panel read 11.9v. Then I plugged shore power back in.
It was actually cloudy.
|
swimmer_spe
|
11/02/22 12:44pm |
Tech Issues
|
|
RE: Solar power
It was close to freezing.
I do not know how often it was on, but when on, it was only for a few minutes.
Fridge was off.
No other power draws. Lights were off.
My hope was that the existing solar panel could allow me to last 1 week in these weather conditions. Since i can't, I will be bringing a generator and running it for a few hours to recharge and have extra batteries to parallel or swap in/out.
How often/long it's on is what counts. Down into the 30's, ours doesn't run much.
Realistically boondocking, you will have the fridge, lights and other draws to add into the mix. Best to do an energy audit and estimate everything (what is the wattage and what percent of the time is it running to calculate total w-hr), then work from there.
For a day or two of boondocking, you can cheat and let the battery run down with the idea of plugging in at the next campground or when you get home to fully top it up.
For longer time periods, you basically, need to plan on replacing what you consume each day (or at least close to it). While you need at least 2 batteries (maybe more with a realistic energy audit), your big issue is sufficient charging. It's borderline running the fridge in cool conditions (when the compressor on-time is low) but once you add in the furnace, lights and other uses, not even close.
Best to parallel rather than swap batteries if at all possible due to the Peukert Effect. The basic idea is the larger the wattage draw relative to the total watt-hours of a batter bank that you draw, the fewer watt-hours you can pull from the battery bank without depleting it.
Example: Let's say you have 2 - 1200w-hr (rating) batteries (aka: 100amp-hr) and are drawing 240w
- If you parallel them, you have 240w out of 2400w-hr which is about 10%.
- If you swap them, you have 240w out of 1200w-hr which is around 20%, then you swap and are still at 22%.
Even though the ratings are the same, you might get 2600w-hr at 11% vs 2200w-hr at 22% once you are done (you would have to get the manufacturers specs for specific impacts but the principal holds)
Easy enough for me to do as I have a good second deep cell and was planning on getting a new one as I have another that is bad. If the good battery is the same, I'll use it, otherwise, I'll get a new one to match the one the trailer came with.
|
swimmer_spe
|
11/02/22 12:43pm |
Tech Issues
|
|
RE: Solar power
OP here.
I plugged it back in. It rebounded to 11.9V
I now know.
Do you mean you were charging it? Or just measuring the voltage (at the battery posts would be preferred.
40% is a bit too low.
I was reading off my panel in the trailer. The rebound I am assuming was due to the solar panel. Not bad, but definitely not good.
|
swimmer_spe
|
11/01/22 10:41pm |
Tech Issues
|
|
RE: Solar power
Op here.
I am doing a test. Just the furnace on, started with 12.7V. 24 hours later and now it is 11.5V
What was the weather and what percentage of the time was the furnace actually operating? Running for 3-5min out of each hour in mildly cool weather is wildly different from running 30min out of each hour in colder weather.
Did you turn off the fridge?
Were any other 12v draws in operation?
Regardless, take the battery down to 11.5v (90% discharged) frequently and it will quickly lose capacity and need replacement. Generally, you don't want to go below 50% (around 12.1v after the load is removed).
A second battery would likely keep you up around 50% after 24hr but I'm not sure if it was a valid test (not knowing the full conditions).
The next question would be how are you replacing the energy consumed. We don't boondock a lot, so a bit of generator time in the morning & evening along with the 50w panel does fine. If we were boondocking a lot, we would want bigger panels.
It was close to freezing.
I do not know how often it was on, but when on, it was only for a few minutes.
Fridge was off.
No other power draws. Lights were off.
My hope was that the existing solar panel could allow me to last 1 week in these weather conditions. Since i can't, I will be bringing a generator and running it for a few hours to recharge and have extra batteries to parallel or swap in/out.
|
swimmer_spe
|
11/01/22 10:40pm |
Tech Issues
|
|
