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ouR escaPOD mods |
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StephenH 
podders Helping podders - pHp 
Joined: 29 Nov 2015 Location: Wake Forest, NC Online Status: Offline Posts: 6289 |
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 Topic: ouR escaPOD modsPosted: 05 Jul 2021 at 11:35am |
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Control is just one setting. No separate fridge/freezer controls. I was testing with it on the next to highest setting. I had it on highest and the refrigerator almost turned into a freezer.
I'm sure I can keep ice cream in the freezer easily.
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StephenH
Happy is the man that findeth wisdom,... ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
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Olddawgsrule
Senior Member
Joined: 20 Sep 2017 Location: New Hampshire Online Status: Offline Posts: 1014 |
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Posted: 05 Jul 2021 at 10:30am |
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I talked to several folk that run 12v frig's and estimates of increase draw are all over the place.. Far too many factors involved. I tested mine empty when I first received it and it was barely 10% off empty/full. I've heard folks say they were up to 50% off... Mine being chest style and yours upright should really make no difference. Closed frig is just that. The company stated numbers on your unit are very close to what I see on mine. Mine is smaller, so numbers are as well, almost exactly by size. I would expect you would see better performance once loaded up. Didn't note if you had separate freeze/frig controls. Mine does not, so that again could be a reason for higher numbers.
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StephenH
podders Helping podders - pHp
Joined: 29 Nov 2015 Location: Wake Forest, NC Online Status: Offline Posts: 6289 |
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Posted: 05 Jul 2021 at 9:06am |
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The figures would have included the ghost draws. I was testing while empty so the numbers are higher than just the refrigerator power draw. There was also a little LED light use included as well. In any case, while we are using it, there will be other items (lights, fans, etc.) using power as well. In any case, it is workable and I am considering adding another battery in parallel or just replacing the 100AH model with a 200AH model. I also looked into additional solar power. Since the kit I already have has a controller that would handle up to 200W, I could add another 100W suitcase without the controller except that I did not see that available on the Renogy site. I have an inquiry in about that. Since my solar is Renogy, I'm not sure if teaming another panel that is not the same type of cells would be okay. As I said, I don't really have a good way to isolate just the refrigerator draw. Also, when it is full, power use would likely be different also as it would have the mass of the contents to buffer temperature changes. The figures I provided are just a 12 hour test on battery power and are only a rough idea of what use would be like on an actual trip.
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StephenH
Happy is the man that findeth wisdom,... ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
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Olddawgsrule
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Joined: 20 Sep 2017 Location: New Hampshire Online Status: Offline Posts: 1014 |
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Posted: 05 Jul 2021 at 8:32am |
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Curious what you base this on.. " I'll stick with my guesstimate that you'll be 75 amp hours per day or higher in hot weather,"
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offgrid
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Joined: 23 Jul 2018 Online Status: Offline Posts: 5290 |
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Posted: 05 Jul 2021 at 6:56am |
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StephenH, I didn't see a sketch but if you place a shunt between each battery negative and a common negative connection point, then connect from there to your 12v system negative, that should work fine. Try to keep the total length of cable run the same to both batteries.
Re your fridge load, I think there is a bit of confusion still on your units. There is no unit of amps/hour. I think you mean that your fridge is using about 27 amp hours in 12 hours (around 54 amp hours per day). That's pretty good efficiency. But it's not really very hot weather right now in our area. I'll stick with my guesstimate that you'll be 75 amp hours per day or higher in hot weather, more if you are opening and closing the fridge much and/or putting warm things in there. Of course, you have additional load to provide energy for, as you say. |
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1994 Chinook Concourse
1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
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Olddawgsrule
Senior Member
Joined: 20 Sep 2017 Location: New Hampshire Online Status: Offline Posts: 1014 |
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Posted: 05 Jul 2021 at 5:56am |
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You still have some ghost draw to account for... Have you ever figured that out?
Spec's on your unit state: (.36DC@5/23C), (KWH/24hr) That works out to an 1.15ah average (using 13.1v). Are you testing while empty? That will skew the numbers higher. Assuming this is your unit: https://www.dometic.com/en-us/outdoor/food-and-beverage/refrigerators/rv-refrigerators/dometic-crx-110e-56279 |
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StephenH
podders Helping podders - pHp
Joined: 29 Nov 2015 Location: Wake Forest, NC Online Status: Offline Posts: 6289 |
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Posted: 04 Jul 2021 at 7:55pm |
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Okay. Here are some stats on refrigerator power use:
Start time Battery % Battery Amps Ambient Temperature Refrigerator Temperature 08:43 99.8% 99.78A 62.6F 39.7F 14:45 87% 86.9A 85.1F 40.4F 20.43 72.3% 72.29A 78.9F 41.3F Power use over 12 hours: 27.48A Average power use: 2.29A/hour Projected battery life: 43.67 hours (100A/2.29A) In reality, this would be much less since we would be using power for lights, fans, etc. This test was run with just the refrigerator running plus the normal parasitic draws. We would need to be traveling during the day so the DC to DC charger could recharge the battery or if we were sitting still, would need to run the generator to recharge the battery. The 100W solar panel would extend the battery life, but would likely not be able to keep up with the demand.
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StephenH
Happy is the man that findeth wisdom,... ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
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StephenH
podders Helping podders - pHp
Joined: 29 Nov 2015 Location: Wake Forest, NC Online Status: Offline Posts: 6289 |
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Posted: 04 Jul 2021 at 7:08am |
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Current setup has positive connected though cut-off switch and fuse into the system with a separate wire to the DC to DC charger. Negative has a wire to the shunt and then to the converter with another wire for the DC to DC charger that connects to the system side of the shunt so that power into the battery is also read. Proposed setup has the two positives connected. The positive for one would be connected to the cut-off switch and fuse into the system. Would I put a shunt on the one connected to the system and run that to the second battery, then a shunt on the second battery that would connect to the system or would I use something like a Y cable with shunts on each battery and the Y cable from the shunts to the system and DC to DC charger? Also, I started a test. I started the refrigerator cooling last night. This morning, I took readings on battery charge state, ambient and internal temperatures and time. Later today, I will check these parameters. That should give me an idea of power use. High today is projected to be 87F. This afternoon, I will check and see how much power is remaining. If it is good, I will extend the test into this evening. If it is still good, I may let it go overnight.
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StephenH
Happy is the man that findeth wisdom,... ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
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offgrid
Senior Member
Joined: 23 Jul 2018 Online Status: Offline Posts: 5290 |
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Posted: 03 Jul 2021 at 6:25pm |
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Since each battery has a dedicated BMS which is keeping all the cell voltages within a tight range of each other, the only issue you could have with two parallel batteries would be if one has significantly lower internal resistance than the other and so gets more charge current and provides more discharge current than the other. If you place individual amp hour/energy monitors on each battery you would know if that is happening. There are ways of compensating for that in the unlikely event that if becomes an issue.
As with PbA batteries of course you should take the pos output from one and the neg from the other so they're balanced as well as possible. |
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1994 Chinook Concourse
1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
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StephenH
podders Helping podders - pHp
Joined: 29 Nov 2015 Location: Wake Forest, NC Online Status: Offline Posts: 6289 |
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Posted: 03 Jul 2021 at 6:05pm |
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Thanks Dave & Marlene. I'll keep track of power use and decide based on that whether a battery change is needed for our style of travel/camping.
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StephenH
Happy is the man that findeth wisdom,... ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
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