Poor battery life & Solar not helping

[Modersical]

My unit is less than 6 months old, with pair of big 12V batts. Can’t see the sides of strapped in batts to know if they are 24's or 27's, but they are huge. I have recently purchased the 120 Watt Nature Power Briefcase solar panel that according to my volt meter puts out good voltage.

However, if much usage of batts overnight, the solar panel will not charge from depleted state. Trouble shooting says if battery level is too low, charge first, but that is why I got solar panel . . . To charge batteries. If you have alternate charging source, why have a solar panel? Is there anyway around this? Hope you guys with experience are still monitoring.

I am mostly wanting to keep good enough charge to run electric panel on fridge to keep cold. I understand about the parasitic drain, and in reading others exchanges, have decided I may need to unplug 12v Furion TV's when not in use. This rig was already planned and built when I got it, and there are 3 TV's, as well as the sound system. I see where I can unplug the TV's, but not sound system. I guess I could pull fuse???

[sourdough]

You know, I do not use, or have extensive knowledge about using solar panels for powering an RV in the boonies, but.....I visited with a fellow on the W Fork of the San Juan river in CO. He had is trailer parked in a "boonie" location. He had a solar panel that was approx. 4' high and 20' long to power his trailer. I don't think folks talking about 20W - 120W will have that kind of array. He said that is what it took to power his trailer.

[flybouy]

Watts divided by voltage equals amps so if voltage is 12 and watts is 100 you are getting a whopping 1.2 amp charge from your 100 watt solar panel BUT that's if it's generating energy at 100% which can only be achieved in DIRECT SUNLIGHT. In other words the solar panel can not be at an angle to the suns rays so if your at any significant north or south latitude away from the equator or any factor such as air pollution, pollen, clouds, etc it will not operate at full capacity. IMHO anything under 400 watts is useless for anything but a battery maintainer (tickle charger).

[SC Dreamer]

Most solar panels produce closer to 17vdc, that would yield about 7 amps in ideal circumstances with your 120w. May not be enough as already stated. I went with 400w to hopefully get 20 or more amps. With hours of good daylight, I may or may not be able to fully charge. Time will tell and I have on board genny for when it doesn't. Just won't have to run it as long I hope. My charger in float mode with just parasitic drains is sending around 4 amps to batteries for a comparison, so 7 isn't much.

[Canonman]

I have verified our Zamp portable solar produces close to 17vdc at 11.4 . amps, confirming Dreamer's post.
To the OP's issue, bringing a battery from a discharge state of 50% or more might require more amperage than his 120 watt system is capable of. Checking Nature Power's web site was no help in discovering the actual amp output of his system. Zamp's 120v system specs are 17vdc at 6.8 amps. Fewer amps means longer recharge time. Add the issue of cloudy days, sun angle and the resulting less than optimal output from the solar panels and returning the batteries to full charge might not be achievable in a single day.
Solar charging systems have their limitations and therefore are no alternative to judicious, conservative consumption. I would agree with the OP that he look at overall power consumption and ways to possibly reduce the battery draw. Also, a small (750w) generator makes a good backup to solar for those less than optimal solar days or excessive discharge situations.

[JimMSCL]

Could it be your Refrigerator?

Perhaps shut off refrigerator overnight and see if there is a difference.
Certain Dometics have a “Climate Control *Circuit” Eseentially a small heater in the cabinet wall to dry up sweating. This is a 12v circuit. Not sure what years and models. This is a heater, albeit small, but a significant power drain. Such a drain would be huge compared to parasitic drain of TVs and such

From Dometic Manual
According to pg 8 of the DM 2852 manual,*"The climate control switch is located beneath the top decoration panel that houses the control panel"* So, if there is a switch, it can be turned off in this model. It also states that*"when turned on, the climate control will draw 12 V DC power continuously. Turn it off when a charging source is not available."*(pg 5)*

The DM 2852 is a 110 v AC or LP gas only, 12v DC for control board, light, and*Climate Control.

But apparently they eliminated the switch but have never reflected that change in the manuals.
“There is no switch because on the newer units they eliminated the switch and made the climate control a built in feature that you cannot turn off."*

From Dometic
We do not advise that the wiring be altered, and doing so would result in any warranty being voided. The wiring schematic shows which connector controls this on the board. It is tied in with the interior light, so if the customer does choose to disconnect the wire he would not have an interior light. Here is a breakdown with the wiring schematic at the bottom in case you do not have one. “

There is a very good write up on another board on how to disable, with pictures, I doubt I can post link but a creative search should locate it.

[chuckster57]

Welcome to the forum

Perhaps shut off refrigerator overnight and see if there is a difference.
Certain Dometics have a “Climate Control *Circuit” Eseentially a small heater in the cabinet wall to dry up sweating. This is a 12v circuit. Not sure what years and models.

The only Heated circuit I am aware of is in the door seals. Cant say I've ever seen a 'Heater" in the cabinet.

[JimMSCL]

The "Climate Control" switch controls a 12 volt heat tape behind the metal frame around the refrigerator and freezer doors.

They refer to it on their website

And as manual says, they tell you to shut it off if not on AC



I could post links to visually show but not sure that would be allowed

People have cut this wire at the light instead of disconnecting circuit at board so they still had light and rigged a switch or a simple spade connector to enable disconnect.
Seems ridiculous to have to do this.to use a propane refrig for camping

[chuckster57]

A link to show it visually would be allowed, I not saying it doesn't exist, Ive never paid attention and noticed when I have removed Dometic refers.

[chuckster57]

Thank you for the link.

[bill-e]

So I measure about 1/2 amp parasitic drain from the frame heater on my 8cf Fridge. I installed the switch in the light circuit.

My 200w Zamp panel puts out about 14a (verified) at peak her in New Hampshire. Zamp claims it's good enough for the average camper as it can charge about 40-60ah a day and that they believe the average camper uses around 40ah/day. It certainly works for my usage.

I'm going to guess that your 120w panels are good for about 30ah in a normal day. So lets just suppose that you have 200ah of battery and discharge it 50%, it would take you 3+ days to recharge it.

You should go to one of the online solar power consumption web pages and enter your data, it will give you an idea of what your consumption is per day.

I'm guessing your panel is undersized for what you want.

[tomd]

Did you get a MPPT solar controler or PWM? You may not be taking advantage of the solar panel capability if you don't have MPPT controller. PWM throws away power if voltage is in excess of battery setpoint, but MPPT will convert to charge current best for solar power available. Also, if you hook panels up in series (say even 75 Volts or so) you can get more efficient charging and less voltage drops to battery with MPPT, check out info on that.
You may be surprised of amount of current loads draw, a battery off switch will help a lot when you don't need any power on, to give recharge some time.

[Steve/]

We can guess all day as to what you need. If it was me I would measure how much current is flowing when all is turn off. I found I had a 1.6 amp drain. I found the refrig door heater was drawing 1.2 amp. I disconnected it. (do search on site to see how to do this mod, other have done.) I have a 100 watt solar panel mounted to trailer roof, (that take care of the trailer when in storage) with only water pump and heater and lights, it keeps up with needs when camping, if I have good sunlight. I can forget about watching TV and trying to run a 110 volt inverter. At yellowstone this May, I was running the generator for 45 min in the morning ( that when the battery are low and will except the most charge ) and the solar panel would top off the battery during the day, we were getting a lot of rain and clouds. Temp were in the low 30 every night so heater was being used. I think you may need a little more solar panels up around 200 Watts.

[bill-e]

Here's my mod. Also replaced the bulb with an LED.

[madmaxmutt]

Originally Posted by bill-e

Here's my mod. Also replaced the bulb with an LED.

Nice work. I would have just put it inline behind the fixture instead of cutting the wire.

[bill-e]

Originally Posted by madmaxmutt

Nice work. I would have just put it inline behind the fixture instead of cutting the wire.

That's why they make dikes

[WJQ]

Nice fridge mod! Where did you find the white switch and the led?

[bill-e]

The exact ones I ordered are no longer available but these should work.

LED

Switch

[Allen Arin]

Try these tips it seems to work
1-limit the use of batteries the more batteries equal more connection increases the resistance can cause uneven charging.

2-Rotate your batteries if you have large bank of batteries rotate the batteries within the bank

3- Use large battery interconnect cables i Suggest you to use 4/0 size cable for 12v and 24v systems and 2/0 for 48v systems

4- not charging batteries can be damaging and use only distilled water

Hope this helps you out