A few years ago I participated in a kickstarter to get the coolest cooler. It took a really really long time to get my cooler delivered to me (as of last week there were still people who had not received their cooler yet). This thing had it all: a built in blender, cutting board, usb charging port, a bottle opener, a speaker, etc...
I used the battery a total of twice in over a year as my daughter had just been born and we weren't about to take a newborn into hot environments necessitating a cold blended beverage. When I went to charge the battery again about 6 months later it wouldn't charge at all.
I attempted to contact customer support, but the place on their website where you could type the messages to the company didn't have a submit button. It was like they knew they had people wanting to get in touch with them, but they didn't actually want anybody to get through. I reached out through the kickstarter page and never heard anything back either. About a year went by and I just figured that I was shit out of luck and they sent out an email advertising new batteries for sale. I reached out again at the email address they provided and their response was cordial, but didn't help me out at all: "The rate of capacity loss depends on many factors including time between uses, total storage time, and adherence to care requirements as specified in the Coolest Owner's Manual. Your Coolest came with a standard one year warranty, and beyond the warranty period, it's up to you to care for the CoolestBattery."
So I went with a Hail Mary and attempted to revive my battery.
Disclaimer - Try at your own risk
My understanding is that lithium ion batteries are supposed to be maintained in a certain voltage range. Too high and you have a chance of it blowing up. Too low and you have a chance of blowing up as well because it's usually indicative of a problem of being able to hold a charge properly. Because of this there's a little controller inside of a battery that shuts off all activity if tripped by the voltage not being in the proper range.
Needed Items:
Drained Coolest Battery
Good Lithium Ion battery - I used a Ryobi 18V battery fully charged
Some Duct Tape
Wire cutters/strippers
12 or 14 gauge electrical wire - insulated about a foot long
Voltmeter (Not necessary, but helpful to verify that things are working)
A utility knife or pocket knife
Safety glasses or sunglasses
My battery had been totally drained for over a year. As such I know that it was reading between 0 and 1 volt using my trusty voltmeter (not absolutely necessary, but if you own one I'd pull it out or borrow one from a friend). I needed to get the voltage reading to about 5 volts before I thought that the charger would kick and give me a solid charge.
WARNING - We are draining 1 battery into another; ONLY use another battery that has equal or less voltage capacity than the Coolest Battery (21V)
Take length of electrical wire and remove outside shielding keeping the 2-4 strands together.
Take 2 of the lengths of wire inside and remove about an inch of the plastic insulation from both ends. DO NOT USE the bare grounding wire.
Take a good length of duct tape and wrap 1 of each wires into place on the exposed terminal on the good battery. You can test out if you have a good connection by touching the other 2 exposed ends together and they'll stick slightly because you're essentially welding them together. You can do this once to test, but don't continue doing it.
I then plugged the negative end from the good battery into the negative port on the coolest battery. I then plugged the positive end from the good battery into the positive port on the coolest battery.
I let it sit for about 10 minutes and there was then enough of a charge in the coolest battery to take a charge in the coolest battery charger. After a few hours I had a 20.6 V charge that wasn't dropping.
There you have it folks. I now have a working coolest cooler battery that I'll make a point to charge every so often to ensure that I don't have it go to sleep again.
This method didn't work for me strictly as presented. I had to open up the battery and apply the wires directly to the positive and negative strips connecting to the battery pack itself (bypassing the controller). Not sure how safe this was but it worked like a charm and balanced out both batteries to about 17v in about 30min (from 20.6v on the Ryobi). More than enough to jumpstart the charger.
Just wanted to let anyone now on this post that I tired this method with a 20v dewalt battery to the Coolest bat. CB was only reading 0.5v when started I let the DB trickle charge the CB for about 8hr. The CB read 0.7v after, when I plugged the CB in to charge it was enough to just start the process and let it charge overnight.. It fully charged and reading 21.5v!! Thanks for this idea!
I tried this method, left the transfer connection on all night. thought it didn't work. Low and behold when I put it on the charger the green charging light came on. Saved me from waiting for a replacement on a slow boat from China. THANKS!