Backchannel: Alpicool C15 + Jackery 500

from an Amazon product question for the community:

How does anyone feel about using [the [Alpicool C15](https://amzn.to/2ZHrJs1) compressor fridge] with a [Jackery 500](https://amzn.to/34iYdMP)? I'd love to hear from the more battery-math folks! Any thoughts are appreciated!

I’m not really a battery-math person, but I’ll take a first swing at it and other folks can chime in with corrections.

The Alpi is great, no caveats there. My feelings are that $500 for the Jack is an expensive way to get 40Ah of usable battery capacity. Such devices are set up for convenience on short outings. Not a fit for me, but maybe it is for you.

As far as the math, the capacity of the Jackery is “518Wh/144,400mAh”. Let’s decode that spec: 518Wh is an accurate measure of capacity, equating to about 40Ah @ 12v. Normally I’d say the use of Wh instead of Ah is puffery, but in this case there is a good reason for it (beyond the scope of this comment). Since the little Alpicool pulls about 12A/day, we can assume the Jack will power the fridge for about three days between charges if you run it off the DC outlet. Running the fridge off the the 100v inverter in the Jack would impose inverter-related losses of about 10%, cutting it close on the three days.

The “144,400mAh” spec given up top is deliberately misleading. First off, that’s a fluffy way to write 144.4Ah. Second off, you can’t get 144.4Ah out of the device since that figure was achieved by multiplying the capacity of each individual lithium cell by 3.6v. You cannot access the individual cells so the figure is meaningless for practical purposes. The real information can be found if you look up the unit on the Jackery website and click on the Specs tab: “144,400 mAh / 3.6V”

I’m not saying the Jack is a bad unit. I’m sure it works as described and I like the higher internal voltage. The ideal customer would be charging on friday and camping over the weekend. Easy peasy. For longer outings, the long charging times (8hrs on wall socket, 12hrs driving or solar) would put a stick in your spokes. What happens to the food in the fridge if you have to take the Jack into Starbucks to charge?

What kind of vehicle is this going in? If van, SUV, Subaru or other adventure chariot :-) and you camp often (or fulltime) , consider what you could get for that same $500 if you are careful:

• 2x 100w Renogy poly panels, as their lower Vmp works better with inexpensive chargers (see below)

• 20Ah simple (PWM or shunt) charge controller – I actually prefer the dirt cheap / low-tech shunt here because the Vabs on it is user-configurable. Holding Vabs continuously during sunlight can has cheezburger have multiple benefits for small solar installs that are worked hard.

• constant duty solenoid for alternator charging

• 100Ah AGM batttery, for 50Ah usable (20% more than the Jack 500)

• small pure sine wave inverter (<=300w) with usb ports

This solution would yield power automatically and practically forever. No hunting for power outlets. Zombies could take over the grid and you’d have cold beer in the fridge in the middle of Idaho. Or you could store insulin or zombie vaccine. Or more beer.