Second battery to run refrigerator

40ah battery will need to be recharged twice as often as a 100ah battery, so for a little more cash you will get twice the overall life. Also if something goes bad on a system you built you can replace components, unlike a "all in one" you toss it and spend another $750-$1000 to replace it.

 

Footprint/size was a factor in my decision. 100ah Lithium is just too large of a footprint for what I was going after. Also, with a 100W panel, I can top the PB40 off each day in a few hours, so the 40ah with the solar for my application is near limitless. I get what you're saying about building your own and the ability to replace components as needed, however I have trust in Dometic that they produce very reliable products.

 

It's got nothing on my home made version :^)

 

After saying that I tested my Jackery before leaving for work by turning on the AC outlet with nothing plugged into it and when I got home from work it was still on and the unit was down to 93%. I think I was mistaking it with the bed outlet.

 

very nice! how many amp hours is that set up?

 

Theoretically 110ah if the cells are all really 5.5ah. But I doubt it, so I'll go with 100ah.

4s20p 32650

 

What is the voltage of each individual cell?

EDIT, nevermind, looks like you took apart a battery and built this? interesting.

 

3.2v

80 of these.....

This guy did something similar, although not as functional:

http://www.kerrywong.com/2017/09/22/building-a-12v-110ah-battery-bank-using-80-32650-lifepo4-cells/

 

Yeah... wow. Nice work. So 120AH at 12.8V, or were the ones you actually used 5.5 vs 6AH like the ones in the pic?

 

Mine say 5.5ah. I made the pack several years ago and I don't think there were any 6ah available at that time. The rating on the side of those Chinese batteries is almost always "best case" anyway. The guy in the link I posted above put his bank under a 107amp load, and nothing burnt up.... I put a 60amp circuit breaker in mine, enough for a 600w continuous inverter.

 

Since all this commotion got stirred up about pass through charging with the Jackery I decided to set it up in my house and monitor it to see if I can get it to fail or at least notice some overheating. I'm working from home these days so it was easy to look at it multiple times throughout the day. I started this yesterday so it's only been about 24 hours. I have the Jackery 240 and run a Dometic CFX 35. I connected the fridge using the 12v DC connector and the Jackery is plugged into my wall outlet. So far no issues to report. It has not shut down and it does not feel hot. It stays pretty much topped off and I have not seen it dip below 98% charge. My fridge turns on about 2-3 times an hour and runs for about 5 minutes each time. The Jackery shows the input watts as well as the output watts. When the fridge is running I've seen it draw as high as 57w but usually closer to 48w. When the fridge starts to run you can see the Jackery input go up to around 39w while the fridge draws the 48w-57w. Right after the fridge shuts off the Jackery is at about 98% charge and it continues to draw about 39w until it is fully charged. When the fridge is idle it draws 0w-1w. When the Jackery is at 100% charged I've seen it draw 0w all the way up to 9w. These watt measurements are all off the Jackerys display so who knows how accurate they are. At the end of the day I did not notice any malfunction or overheating by pass through charging my fridge. I think the duty cycle for these fidges is short enough and the draw is low enough that it shouldn't cause too much damage, if any. but someone smarter than me please correct me. I'll keep it hooked up for a few more days and report back if I find any issues or overheating.

Edit: After some more experience with the Jackery 240 I learned a few things about it. Make sure to read these two post if you are thinking about the 240

https://www.tacomaworld.com/threads/second-battery-to-run-refrigerator.673769/page-10#post-24053033

https://www.tacomaworld.com/threads/second-battery-to-run-refrigerator.673769/page-9#post-23905664

 

Do you think the actual issue could be the constant topping off of the Jackery batteries? Don't Lithium batteries dislike being discharged only a small percentage and then recharged? I've heard it can degrade the battery quicker than if you sucked it to say 50% then charged to 80 or 90%. And by degrade battery, I mean hurt the number of expected battery discharge cycles.

 

Could be. I'm sure someone on here will school us up. I'd like to know how to use this thing properly and make it last longer. It's been running great for me and for $250 you can't beat it. even if it only lasted me 2-3 years. By then who knows what new tech is out and how cheap it will be.

Edit: some googlefu turned up this page. https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries



And looks like they should be calibrated from time to time



Edit: After some more experience with the Jackery 240 I learned a few things about it. Make sure to read these two post if you are thinking about the 240

https://www.tacomaworld.com/threads/second-battery-to-run-refrigerator.673769/page-10#post-24053033

https://www.tacomaworld.com/threads/second-battery-to-run-refrigerator.673769/page-9#post-23905664

 

I bought this unit off of Amazon. It's a "Chafon" brand. 296Wh. Some selling points are that it does 12V passthrough (so if it's connected to a 12V power source it will also provide 12V power via the appropriate outlet), and it has 60W USB C PD (which I believe also acts as an input). It's got a QI wireless charger on the top, and two AC outlets in the back supporting up to 330W continuous power (pure sine wave).

I intend to use it with a Dometic 11L cooler. It'll be in the cab instead of the bed, and I've got the SR5, so no AC outlet in the bed anyway. It should work a charm...

BUT... one stupid problem. The 12V circuit turns off after 30 seconds if there is <2W load on it. When the cooler's compressor isn't running, it draws <1W. Shit. So I ordered a 6Ω resistor to wire up to plug into the 5.5mm 12V outlet. That should trick it into staying on.

For now, it's connected to a 100W stationary solar panel at home to keep it charged up, and the cooler is connected to a 12V AC adapter. It drops to about 8W when the cooler isn't running, so a 2W load from a resistor on the 12V circuit won't matter much. It's stayed fully charged all day, so I think it should be able to handle the cooler quite well.

 

I also made a 25ah version out of an ammo can....

 

Interesting, thanks for posting that. I still have not had my 500 Jackery arrive but if at all possible I will send back some test info before we start out trip... I did hear back from Jackery and here is what they said...


Sorry for the inconvenience caused to you , and we will make improvement in the future.
And pass-through charging will damage the battery but will affect the lifespan of the battery.

I emailed them some additional questions and will pass on their response...
Again, there are like a dozen folks on the Amazon Q/A section that have been doing pass thru charging, its mentioned about every page of questions.

 

here is a very enlightening article on pass thru charging...

it appears to me they did incorporate pass thru charging for the 240 and 500 Jackery units but then after it was marketed as such (manual says you can and all the blogs and Q/A says you can) and they produced them... they didn't test sufficiently or some components they used didn't meet full design spec (components and manuf of components do this often) or there was a firmware bug, or a chip control subtilty... or something else... that they discovered after the fact that has effected the ability of the internal electronics to effectively and properly manage pass thru charging to the exacting degree that they can not guarantee the battery capacity will not degrade over time.

At least they admit it, there will be a fix, not clear if that is firmware, hardware, different batteries, or a new model entirely... it is also unclear if they will take trade ins at some point as well. I have asked them and will share the response...

https://www.powerbankexpert.com/what-is-pass-through-charging/

 

I’m running a battle born 100a/h lithium battery with the redarc manager 30 BMS. Charged 24/7 by solar, DC to DC and (rarely used) AC connection.

Best setup I can imagine. I can run a small house off grid indefinitely.

 

What would a setup like this set me back?

 

how do you charge via solar when the sun goes down within those 24 hours?!