Single AGM, Fridge, and battery protection

Also, I understand that at camp it will probably be lower than this experiment since fridge would be open more often then at home.

 

And possibly hotter too (another variable).

 

Curious if you've had a chance to do any more investigation of the power draw from this fridge. I'm looking at buying the same one and curious how long it will hold up on a battery.

 

I’ve done a few trips with this setup and have not run into any issues. I make it a rule to have the fridge and food pre chilled before leaving on my trip. Most trips are around 3 days which involve some driving between days. I did do one trip where I was stationary for 2 days. For that trip I used a cheap 150W solar panel. Feel confident now that Imma be ok with this setup. I do top off my battery with a charger before and after my trips to make sure my AGM gets fully charged since my 3rd gen doesn’t charge at the necessary rate to top off AGMs. Looking at OVTune options to get this resolved.

$100 DOKIO 150W 18V Portable Solar Panel Kit (ONLY 9lb) Folding Solar Charger with 2 USB Outputs for 12v Batteries/Power Station AGM LiFePo4 RV Camping Trailer Car Marine……

https://www.amazon.com/dp/B07Y8CT1W9/ref=cm_sw_r_cp_apip_19f8eFP5uz6Oo

 

Forgot to mention I run the fridge on ECo mode and low protection. Only issue I’ve run into is random fridge shutoffs but I think it’s because while off-roading the DC plug gets loose. I started wrapping the tip with some tape to make the connect tighter. Seems to fix the issue.

 

Its really amp draw. Fridge usually only pulls 5 amps and maybe 8+ when the compressor kicks on so a battery can power 5 amps for a long long time, probably a few days

 

this thread is kind of exactly what I'm looking for. I've talked to you a couple times and then dove in off the deep end and got myself a fridge and a 100W solar panel to keep up with it. Dometic CFF45.

RIGHT NOW I am on the stock battery, 24F, LA. I've noticed a few mornings after cloudy days, the fridge is off and down to about 45deg (set to 37). Right now, I don't care, I have a couple cans of beer and a gallon of water to have something in there to keep an eye on it. Medium voltage cutoff.

Did you start with a stock battery or go straight to AGM 27F?

my plan is when this battery dies to go up to 27F AGM, BUT I might be needing to bite that bullet sooner than later if the LA 24F can't keep up. We're only in spring time so maybe a COUPLE days in the 70s so far.

I know this is almost 4 years old but if you're still active, I have a 100W solar panel hooked up to an MPPT controller. I have a stock 24F right now so the MPPT is set to LA 12V, BUT I can push a button and it will go to AGM 12V, which will charge to the higher voltage for AGMs. Two birds, one stone, it will keep the battery topped up to the right voltage AND keep the fridge going, without tuning the ECU.

Allto Solar Intelligent 10A MPPT Solar Charge Controller,10 Amp 12 Volt Solar Panel Regulator with Digital LCD Display + Temp Sensor + Charging Level for 12 Volt Wet Gel AGM Lithium LiFePO4 Battery

https://www.amazon.com/Allto-Solar-...&sprefix=solar+mppt+controlle,aps,117&sr=8-26

I got this one with a 20W panel to keep the battery topped up on my 1.5 mile commute pulling it down. But it will go up to 120W, and I currently have a 100W on it for the fridge.

 

Switch to a 27f agm. I ran my stock battery for a while but I got like 2-5x the run time off the agm before I added the solar.

After doing the agm and cascadia solar panel, I never had issues even staying parked for a couple days at a time. I’ve actually never hit the low voltage cutoff with the agm installed.

I’m usually on the move every day but if you aren’t, a 80-150w solar panel is plenty to keep the fridge going basically forever unless there’s no sun. You can always get a secondary portable panel or run the vehicle for a while if you are staying parked for an extended period.

 

From my offgrid Baja fish camp setup you should know that ideal draw on an agm will only pull approx 30% of the capacity and refills during the day. Pulling 50% or more regularly will degrade the agm and lead to an early grave. Lithium is way more forgiving.

 

Cheers thanks - I thought the stock would keep up for a while, but I guess I'm making that switch earlier than planned. Fortunately it's a drop in swap for me

During the day it's fine, and keeps the battery up, but I think the overnights it doesn't quite have the reserve capacity to run it, especially if the day before is rainy/cloudy and warm. I had a suspicion it was the 24F LA vs 27F AGM.

It's 4.5 years old (since I've had it, probably closer to 5 years since MFG date), so it's not like it's a huge loss. Maybe I can get someone to buy it on FBM for more than a core deposit

 

I ended up getting the truck tuned to help with the shifting. Did an AGM add on for a few dollars more so ecu now allows for proper charging of AGM. Been a few years and all is still well.

 

I was going to mention this as well but looks like youre on top of it. My agm battery died prematurely and the fridge kept shutting off during my last trip.

 

I have a SwitchPros that allows me to check battery voltage on the fly. Im also able to see voltage in the bed of the truck due to my blue sea distribution panel. it's usually a little lower but ima assuming thats dues to the long wire run. The only thing I dont really like is that my fridge always displays a lot lower voltage than actual so there are times that the battery protection shuts the fridge off because it thinks its too low. The only happened once during a beach camping trip. Portable solar panel resolved that issue.

Fridge is an iceco. Wish it had bluetooth feature so I can verify that it's still running and hasn't randomly shut off but hey it is what it is. Got it for like $400 when they first came out.

 

That's what I'm using my solar panel for. You can get the 20W and it'll do the same thing. Or an ECU tune, but hey the sun is free

Nice. I was considering an iceco but bit the bullet and got the dometic. I don't regret it.

Throw this in there.

$17 ThermoPro TP200B Indoor Outdoor Thermometer Wireless 500FT, Outside Greenhouse Thermometer with Temperature Sensor, Outdoor Thermometers for Patio Reptile House Home Baby Room Temperature Monitor

https://www.amazon.com/dp/B0936QGQW4

 

Swapped it last night, obviously it's only one night but so far, success! Woke up and the fridge was still running, and didn't have the solar to top it up after I started the truck after install.

Might have to consider a relocate away from the rad supports

 

Okay another question - thanks again for all your help already.
What is your voltage cutoff? The Dometic CFF45 high is 11.8, which is kind of low for an AGM.
But it's really all I can get out of it. Unless I install another unit in line as a monitor cutoff, but I'd prefer to not have to do such a thing.

 

I don’t believe I ever changed mine from high

 

So last night, around 7-8ish or so, checked on everything. The MPPT controller is at the battery, and was bouncing between 12.9 and 13V, 0A coming from the solar (late in the evening).

The fridge had cut off for low voltage. So, whatever my voltage drop calculation said - was completely wrong. I suspect the connectors may be the limiting factor. I changed the voltage protection back to MED.

Then, for the fun of it, I dumped a TON of room temp water bottles in. I plan to use these as a thermal mass anyway, but I wanted to play around with it. When this started, the water bottles were room temperature (they were in the back seat just bought). Fridge is set to 36.

Ahead of this - the gallon jug and the two Arizona iced teas (under the steel mug) were in there and down to temp. And I didn't count how many water bottles because this was more so messing around.





The fridge was down to temp, but the sensor just got thrown in, so that was soaking before I did this.

I'm happy with the results. No solar backup and it brought the entire thermal mass of all that water down to temp overnight. The fridge was showing 41 when I checked it this morning, so I have pretty good confidence in this temp sensor. I might bring it down to 32 or 30 for trips, and plan to re-fill beer/wine takings in the morning when the solar can kick it in better. But overall, the 27F AGM was really the game changer for this. I am cautiously optimistic with confidence for this.

In August I'm doing a week+a couple days where I won't be moving, and will be using the fridge. So I will report back then with more data!

Anyway, wanted to share my results for the next moron truck camper to find this thread like I did!

 

I have my battery protection mode set to low. Here are the settings for my fridge:

Low: 9.6v
Med: 10.1v
High: 11.1v


So in my vehicle I have 3 places I can get a battery voltage reading from:
1. My switchpro (most accurate compared to multimeter since its closes to battery)
2. Bluesea distro panel added to bed of truck that fridge is hooked up to (usually .1 or .2 off compared to switchpros)
3. The fridge itself

What I noticed is when the fridge is at temp and the compressor hasn't kicked on, they are all reading pretty close to each other. But, when the compressor kicks on, the fridge starts reading way lower that the other 2, it stays this way the whole time the compressor is on. When the compressor shuts off, it goes back to reading like the other two. When I had the fridge set to high, this would cause the fridge to shut off prematurely. This is why I set my battery protection to low. My process during a camping trip is to just take a gander at my voltage from my distro panel throughout the trip to make sure voltage doesn't get too low. Have been on running this way for 4 years now with no issues at all.

From my fridge's manual:
"The battery protection mode may be triggered prematurely on certain vehicles due to small wiring imperfections, contributing to a measured DC voltage drop at compressor start-up. Lowering the battery protection setting may resolve this issue."

 

Yeah that's kind of what I have, my MPPT is at the battery. I have a multimeter but that's not a permanent fixture. I'll check the voltage at the battery and the 12V port later tonight if I remember.

Nice choice in wines