Two jump starters at Amazon that work.

Outstanding reviews, too:
Antigravity Batteries XP-10 Jump Starter - Consumer Reports

 

From The Charge of The Light Brigade by Alfred Lord Tennyson (Lord was his middle name, not his title).

The Charge of the Light Brigade (poem) - Wikipedia

 

this is the one i got from groupon. eps multi function 15000mah portable jump starter.

when i tested it again a few months after it worked on a regular car it couldn't turn the engine over strong enough anymore even after full charge.

i believe li-ion batteries have only 2 years lifespan so most products like powerbanks need to go on sale if they aren't sold after a year.

anyway i use a 2amp lead acid charger from ideal power every month or so to top off my prius battery to minimize the chances of getting stuck


iPhone ?

 

duplicate

 

My manufacturer suggested the L-ion battery is recharge every 3 months even if it has not been used to prevent degradation. Most dealers won't want to break the seals to charge their stock. Yes the batteries would last longer, but could they sell them as new to a customer expecting unused?

 

Perhaps they are on sale to clear old stock?