Something I'd suggest would be to use a bench power supply, and slowly bring the battery up to the level where either the charger or the charge controller can then resume operation.

What I'm talking about is something like this. Current-limited is a good way to go; 3A or 5A is a pretty slow charge rate, and may take a while to get you raised up, but this will be a safe and effective method.

Gesswein is Canadian, as is Caswell.

Not knowing where you are, I suggest you searching for a jeweller's supply shop.

In Vancouver there is Lacy West.

I'm pretty sure Rio Grande and/or Ottofrei will ship those chemicals to Canada.

Edited to add, I purchased this power supply from Amazon.com with no problems.

Something I'd suggest would be to use a bench power supply, and slowly bring the battery up to the level where either the charger or the charge controller can then resume operation.

What I'm talking about is something like this. Current-limited is a good way to go; 3A or 5A is a pretty slow charge rate, and may take a while to get you raised up, but this will be a safe and effective method.