Dry Camping and battery

cjcoult · 07-30-2018, 03:58 PM

I have a 2018 Cougar 366RDS - I had to change the battery every day when dry camping. I had a 12v battery solar panel connected to the battery - 7amp max rate. We did not use the lights at all. The only things drawing power were the fridge, water pump and water heater only when in use and CO2 sensor. With nothing on but the CO2 sensor - .45 amps being pulled, CO2 + Fridge flame 1.7 amps and fridge fan + CO2 sensor + (no flame) 2.8 amps. Fan runs very often. If outside temp matters, days were mid 70s and night 50s. I should get more than one day, right?

**JRTJH** · 07-30-2018, 04:38 PM

Quote:

Originally Posted by cjcoult

I have a 2018 Cougar 366RDS - I had to change the battery every day when dry camping. ... I should get more than one day, right?

Iwould guess that you meant to say "charge the battery every day when dry camping"

Depending on the size of the battery, you probably are going to have to charge it daily. If it's a GP24, it's doing all it can do to run the lights and refrigerator for 24 hours. If it's a GP27, you might get nearly 2 days before you'd have to recharge.

A 7 amp solar system really only produces the maximum output on a bright, sunny day, and then, only when the solar array is directed at the sun. As the clouds move between the array and the sun, as the sun's position changes, the output is significantly reduced. Really, about the most you can expect from a 7 amp solar system is a "trickle charge output". So it really won't help much, and certainly won't keep up with the electrical use when dry camping.

If you're planning to do much dry camping, you should consider a dual battery system. Either GP27/GP31 if you want to stay with 12 volt batteries. If that's your plan, try to find "true deep cycle batteries" not "RV/Marine" batteries. They usually aren't "true deep cycle batteries" and don't hold up well to repeated discharging below about 70%. Realistically, if you plan on significant dry camping, I'd suggest a dual 6 volt system using golf cart batteries. Most of us use GC2 or EGC2 size golf cart batteries. For the purchase price, they are hard to beat and provide sufficient power for 3 or 4 days of summer dry camping. Ours are 5 years old and still perform the same as when we bought them. As a comparison, our last 12 volt system lasted 2 camping seasons.

There are several very thorough discussions of battery systems on the forum. Do a search for battery systems or for dry camping and you should locate them.

cjcoult · 07-30-2018, 05:22 PM

First, thank you for the reply. I have 2 GP27 batteries. One used at a time and I charge one, then switch them out and charge the one that was being used... We dry camp once a summer for 10 days. I will do the search you suggested. I was surprised to only get 1 day as I got 3 - 4 days with my old 5th wheel. But this fridge is 12 cu feet and has a fan and my old one was 8 cu feet and didn't have a fan. The fan runs alot and I am wondering if it is running more than it should. Thank you!

Canonman · 07-30-2018, 06:30 PM

Something just doesn't sound right. We also dry camp for multiple days using 2 group 24 batteries connected in parallel. Parallel connection keeps the voltage the same but doubles the amp hours. so two 12v 100 a/h batteries will provide 12vdc and 200 a/h.
Our 200w Zamp solar keeps the batteries topped off quite nicely. We use our lights, watch the occasional movie and have never run the batteries below 12.4 volts.
I'd suggest using your VOM to check the actual voltage of the battery when you install it and also when you remove the battery.12.6vdc or more is a fully charged battery. 12.2vdc is charged at 60%. 12.0vdc is about 50% discharged.
I'm suspecting since you're only using one battery at a time it may be dropping below 12.2vdc by the time you pull it. Your solar charger may not have it fully charged by the time you reinstall it so things just keep going down hill.
I'd also suggest looking at using the batteries in parallel and charging from the solar or generator directly while still connected.
You don't say what size solar you have but to get to 7amps it would have to be 160watt or better. Your solar controller will tell you how many watts/volts /amps the panels are providing and will protect your batteries from over charging. Bottom line, I think your system is capable for your needs and should be working better than it is.
Not sure what the big drain on the batteries is (refrigerator fan?)but I'd find out and see what I could do to minimize it.

**chuckster57** · 07-30-2018, 06:34 PM

Is the fan inside the fridge? Like a Norcold 2118? If so I know from personal experience they will kill a gp27 battery overnight.

If you have an external fan because your refer is on a slide, odds are you have at least 2 fans. They are “activated” by the temp of the cooling unit at the top. There is a “limit switch” that is attached to the last cooling fin and is set to allow current to the fan(s) when the fin temp reaches a set point.

I wouldn’t disable the fan(s) if they are on the back of the fridge because they are a vital part of keeping your fridge/freezer cold.

cjcoult · 07-30-2018, 07:17 PM

I charge the battery using electricity in the campgrounds bathroom. I use the solar panel just to help the battery that is connected to the RV. The fridge is on the slide out with the fan that I hear is at the top of the slide out.

As for the solar panel - I think it is simply too small to make a difference based on what I am reading.

Each time I put in the charged battery back in the trailer - I checked the voltage reading using the panel inside the storage compartment - the leveling control panel...each time is was between 12.9 and 12.6 volts. When I changed the battery is was reading in the low 11s and the inside the trailer indicator was either at 1/3 or E.

How can I figure out what the big draw is on the battery?

Thanks to everyone that is responding, much appreciated.

bill-e · 07-30-2018, 07:34 PM

OK, If I'm reading this correctly, I think that the OP is saying that he owns two batteries, but he only has one installed at a time. for the purpose of my supposition, let's forget the second battery.

So Guessing that it's a 100ah or less battery, you probably only want to discharge it 50% or no more than 50ah. Now with your 7ah solar system, you would need at least 7 hours of the maximum daily sun to bring that battery back up to full. I am also going to assume that the solar is connected to the RV battery, not the second battery.

Having said that, If what you stated is all that drawing power, here's an possible scenario. If we guess at total of 3ah of consumption which works out to 72ah for a 24 hour period, of which your solar is replenishing maybe 30ah on a good day, then you would have 8ah as carryover to the next day (-72ah +30ah = -42ah. 50-42=8ah) which when added to your next day's solar provided 30ah, maybe you should be getting a day and a half before running out of juice at the 50% level. If you've been drawing down your batteries more than that or they're old then you won't actually have a battery that can produce its rated capacity to start with.

Variables in this guess are the amount of sunlight, quality and condition of the battery, and the actual 24 hour current draw.

bill-e · 07-30-2018, 07:43 PM

So 12.2v is the absolute lowest that you should be discharging that battery to without having noticeable damage to its capacity.

cjcoult · 07-30-2018, 07:49 PM

In response to the lowest being 12.2 - I would be changing the battery probably every 12 hours if not sooner - based on the reading when I put the "charged" battery in, the reading was around 12.7 volts. That is a guess as I didn't check the time used when reading was 12.2.

cjcoult · 07-30-2018, 07:57 PM

Part of my issue may be the charging of the battery in the campground's bathroom and/or my charger. The most I got as a reading on the control panel was 12.9 volts, and that was only once - it was usually 12.7. I am home now and had the trailer plugged in to home electricity and unplugged it and checked the voltage reading and it was 13.1. So even tho my charger said "full", maybe the battery isn't really "full". But I am still thinking something is drawing more power than it should be.

bill-e · 07-30-2018, 08:03 PM

What is the ah rating of the battery?
How are you measuring current draw?
How old are the batteries/how many times have they been discharged below 12.2v?

bill-e · 07-30-2018, 08:04 PM

Quote:

Originally Posted by cjcoult

Part of my issue may be the charging of the battery in the campground's bathroom and/or my charger. The most I got as a reading on the control panel was 12.9 volts, and that was only once - it was usually 12.7. I am home now and had the trailer plugged in to home electricity and unplugged it and checked the voltage reading and it was 13.1. So even tho my charger said "full", maybe the battery isn't really "full". But I am still thinking something is drawing more power than it should be.

Check your battery about an hour after it finished charging. Checking it right after charging gives a false high reading.

cjcoult · 07-31-2018, 03:11 PM

100 ah
used a digital amp meter to measure draw
each battery went below 12.2 4 times

Canonman · 07-31-2018, 04:50 PM

So we know you are installing a fully charged 100amp hour battery but within a days time the battery is discharged greater than 50% (12.2vdc or less), which is the max for a lead acid battery. So the use is around 50 amps per day. Your post says you are drawing around 5amps load with the items you tested so the battery is lasting roughly 10 hours? depending on how often the fan runs, pump is used etc. it could be more.
To increase the amp hours available to your accessories, you need to use both batteries at the same time connected in parallel. This will provide double the amp hours as a single battery.
Also, most solar panels can produce about 30 amp hours per 100w per day. In order to keep up with your charging needs you'd need at least a 200w solar system and lots of sunshine. If dry camping is your thing (like it is for us) then I'd suggest a generator to keep the batteries charged.
We're fortunate and have a generator to back up our solar. So for us it's solar to keep the batteries topped off and the generator as needed when the solar can't keep up due to weather or usage. Hope this helps.

cjcoult · 07-31-2018, 05:50 PM

Thanks for your replies everyone. I understand the point of hooking up 2 batteries to get twice the amp hours, but when I use one battery and then use another battery - I am essentially getting the amp hours from both batteries, correct? (I am just not using them at the same time) My issue with using 2 batteries at the same time is that if they need to be charged with electricity in the campground bathroom (can't use a generator at this state park), then I need 2 more to put in while those charge (or I guess at least 1 more to use by itself while the other 2 charge). So I guess I could get 2 days with 2 batteries, then 1 day from one battery while the other 2 charge...And my present solar panel is definetly not enough watts to help so I need to consider buying a new one with much more watts. Right now we only dry camp this one 10 day trip every year.

I am presently charging one of my batteries, so I will wait an hour to see what I get instead of checking right away - the false reading.

cjcoult · 07-31-2018, 06:24 PM

As for waiting an hour - that did happen while dry camping last week. It finished charging in the morning and I didn't put it in until each evening. It was still always 12.6 to 12.9 volts.

bill-e · 07-31-2018, 07:10 PM

cjcoult, great, that means that your battery is fully charged. The few times you've gone beyond 50% should not be a noticeable decrease in your # of cycles as it relates to battery lifetime.

As you've deduced, your battery and charger are working well, you're just using too much per day to keep up with the charging using your small solar setup. The ideal situation would be to consume no more power than your solar system can offset.

In my case I have two T-105 6v batteries which gives me about 110ah of available power at the 50% level. I typically use about 40-50ah/day which includes using my CPAP, running the fridge (heater disconnected), occasional hot water,occasional water pump, occasional awning Plus 4 cups of Keurig coffee using my 1000w inverter. My 200w portable solar panel can just about keep up with that and I get away with not running my generator at all for a 3-4 day outing.

cjcoult · 07-31-2018, 07:50 PM

I agree that I need a solar panel with higher watts. But I still think something is drawing more amps than it should or maybe the fan on the fridge runs more than it should. I am also dry camping for 10 days at a state park that won't allow a generator. I would be happy if I could get 2 days from a battery so I only need to switch every other day instead of every day. I think my next step is to try to figure out what is drawing the amps and how many amps. Thanks.

Canonman · 08-01-2018, 04:46 AM

Now that you're home, why not use the digital amp meter to verify your total amp draw?
Then start pulling fuses and see which device/devices are the big users. Our Cougar was supposed to be equipped with all LED lights. I have found that the light over the stove and the small decorative light over the dinette were the old 921 incandescent bulb.
A 921 bulb will draw 1.5 amps by itself. Worse, we were using these "smaller" lights to save power rather than the main overhead LED lights

Further investigation will at least allow you to know what devices draw what power. You may find a problem that needs to be addressed or just that the ridge fans are the culprit and nothing you can do.
Good luck and please post with what you find out.

**JRTJH** · 08-01-2018, 05:23 AM

One significant drain (if you have a Dometic 2652/2662 or 2852/2862 refrigerator) is the door heater circuit. On the "upgraded '62 models" there is a switch to turn the heater circuit off. It's located under the eyebrow control panel. On the "standard '52 models" there is no switch and the circuit is energized "24/7"... Many of us have modified the refrigerator to allow for disabling that heater circuit. You might do a forum search, read up on the modification and consider whether it would benefit your style of camping. My guess is that it would save you about 1-1.5 amps, which may keep your current battery usage out of the "below 50% discharge" conditions. When dry camping for extended stays, every light bulb, every water pump cycle, every cycle of the refrigerator ignition system helps deplete the battery/batteries.

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