I realize this isn't a MotoBrick topic, but I suspect there may be a few inmates who, like me, cheaped out and dropped $60+ on a ChiCom jump box and then had it crap out after a year.
If you still have it, it can be restored to almost like new. It has an AGM battery that the box's internal charger boiled all the water out(turns out the charger has no float mode. Gotta love those Commies). All you need to do is refill the cells and run a couple charge cycles to dissolve the sulfate that has formed on the plates.
Split the case, remove the battery, pop the plastic cover on the top off and remove the rubber caps on the cells. Fill with distilled water using one of those rubber ear syringes from the drug store. Let it sit overnight and refill. Repeat until it no longer takes the water. My battery took the better part of 6-7 ounces of water over several days.
Once the cells are full, charge until the current drops to less than half an amp, then connect a load to it. I used an old H4 headlight bulb. That will put a 4-5 amp load on the battery. Let it run the light until it's almost going out, then charge and connect the light again.
When charging, watch the current and keep track of the time. This will give you a rough idea of how many amp hours the battery is storing. Example, 4 amps dropping to .2 amps over three hours is the average current (about 2amps) X 3 hours or 6 amp hours. The battery is rated at 17 amp hours so I would shoot for at least 12-13 amp hours of charge once the cells are working again.
Do a load test to confirm the cranking current is good and put it all back together. Finish the charge with the box's internal charger, but watch it to make sure you shut it off as soon as the indicator shows a full charge. In the future, don't let the box charge for more than an hour or two, otherwise you'll boil the water off again.
Congratulations! You just saved enough money to purchase fuel to ride over 800 miles.
P.S. If you have an AGM battery on your bike, this procedure may also help bring it back to life as well.
