CM1936- charger - can i use a car batter charger?

I have a CM1936 Black and Decker mower. I ordered a new battery pack because the battery wasn't taking a charge. The mower worked fine with the new battery, but now I think the problem is the charger. But the charger is no longer available. Can I use a car battery external charger to charge these batteries?

thank yhou

CM1936- charger - can i use a car batter charger?