I have an electric bike, actually 2 bikes and an electric tractor. Most recently, I lost the charger to my main cargo bike and a replacement is on the slow boat from China. In the meantime, I have a 48V pack that needs to be charged. --I am quite anal about my SLA's --Left uncharged for any length of time is death to these batteries.
In addition, I am about to "winterize" the spare e-bike and electric tractor and bring thier batteries inside.