PsyRN
Well-Known Member
- First Name
- Eric
- Joined
- May 13, 2019
- Threads
- 23
- Messages
- 454
- Reaction score
- 522
- Location
- Santa Rosa
- Vehicle(s)
- 2020 StingGray JTR, 2016 Bonneville T120 Black
HOLY COW!Finally got around to doing some updates. Figured it was necessary since the system and a fridge was ordered.
First, some tidbits. I called Fullriver to ask about the battery included in the Genesis kit. Unlike what I heard before, maybe there was miscommunication, it is 64 ah at a 20 hour rate. So that results in a total of 76.8 amps available. Notice this is total amps available. Their tech support group also recommended not going below 70% SOC. I know there are folks here and elsewhere that will debate that, but that is from their tech support so I am inclined to believe they should know what is best for their batteries. Here are a few screenshots of their graphs specifically for this battery if you care to see. (and yes, they said I am over thinking it as well, but to each their own and I want to be sure I don't have a "oops my battery died" half way through the night....)
You can see here that at 30% DOD - which is equal to 70% SOC, the lifecycles of that battery decline at an increasing rate. It seems to take another dive at about 40% DOD / 60% SOC. They did recommend against going below 70% SOC, so the 50% mark where a lot of folks suggest, is drastically reducing the lifecycle. That being said, 500 life cycles for a 30% SOC could quite well be 62 years (solely by the math) if one goes camping only 2 times a month for the 4 months or so of summer (of course we know that is not realistic at all). That being said, as the aux battery degrades, it will start to pull down the main battery with it even though there is a disconnect.
Anyway, ok so now that is straight, I wanted to get the specs of a fridge. Based on what a few others on this forum have said, and some videos and reading I have done, I settled on a Engle 45 combi. (https://engelcoolers.com/collections/powered-fridge-freezers/products/45-combi-portable-car-fridge) I chose this because it has the option of being a fridge/freezer, or just a freezer, or just a fridge. I also did a decent amount of poking around at their compressor and it is well above the competition, IMO. Many of their products are used in ambulances, and even organ transport (according to them of course). It also is a smaller footprint. I have a larger 67L snomaster in the basement being used as a second freezer, and it is much larger than what I truly need... 2-4 day trips is the reality of what I mostly will do, more likely is just an overnighter. So I pulled some data from them as well.
Unfortunately, this particular fridge only displays in C. There are 6 graphs here. 25 Celsius is 77 Fahrenheit. 35 C is 95 F. 5 C is 41 F and -5C is 23 F. I circled in red the 'position' my conditions are assumed to most likely to be in. You can see it is between 4 graphs, so some assumptions and interpolation had to be done to arrive at my estimated 0.94 amps per hour spec that was calculated. This is drastically different than the actual measured consumption of my snomaster which was closer to 3 or even 4 full amps per hour (it's also a 67L though).
So next I wanted to see, realistically, as in my original question to this thread, how long one could expect to run this fridge, and only this fridge, on the Fullriver Full Throttle group 25 battery (https://fullriverbattery.com/batteries/part-ft750-25/). So I plotted it out on a spreadsheet. The results, though not really surprising because I had some suspicions, are in fact humbling.
According to the math, with a full battery alone (no solar) this particular fridge with assumptions and estimations made should run, with the engine off, for 1.02 days (or 24 hours) until the battery has reached the 70% SOC point where the company recommends charging at. So, that's basically an afternoon of arriving at camp, sleeping, and a few hours in the morning before taking off - not terrible, but not desired either. So I extended it. I wanted to see what a more realistic number would be considering I do plan on adding a small RV style 12v water pump, instant water heater, maybe some lights, and maybe to charge my phone or something if I forgot to have it plugged in while driving.
As you can see, with all these things running, and plenty of estimations made, you get about 0.90 days (or 24 hours) out of the deal. Now that's sitting, camped out, no engine, no solar, just battery drain. Not bad really. Plenty enough for a nice fun weekend! (although recharge time is still of question!!!)
Now, seeing as how Genesis also offers a kit for the Diesel and 392 options, with a larger Group 31 battery https://fullriverbattery.com/batteries/part-ft1100-31st/), I wondered - now what would the potential stay be if I added that battery and connected it to the Group 25 under the hood. Could I go on a longer trip? Say, a 5-10 day trip with a veterans group local to my area? Well...maybe. those numbers come up to 2.43 days. So that entirely depends on how much 'sitting' is being done vs driving.
Adding solar to this, would of course extend all of those numbers depending on the particular solar parts, and quality/quantity of sunlight exposure (which is why I really enjoy Caltopo for trip planning).
So here is the full sheet. Check it out. Feel free to offer suggestions if you wish, or maybe this will just help out somebody else out there who like me is not satisfied with "it will be ok". I wanted the true specs, as close as I could get them without equipment and real world testing. This is important information to make sure that just 'hooking something up' doesn't either cause damage somewhere, cause something to just not work, or ruin a camping trip longed for or worse spending thousands on something that ends up not functioning and needing a few thousand more to make it work right. I found this interesting. Hope others do as well. You will have to do your own calculations and formulas though as I can't attach the whole file
I think I developed an astigmatism and became dyslexic looking at all those graphs, spreadsheets and data points. Bless those who crunch numbers like this because it ain't me.
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