Batboard

Is the saber NTN4734B charger tri-chem?

Doubtful, those chargers were made long before Li-Ion became common in 2 way.

I'd go one step beyond "doubtful" and say no. You need what is called a tri-chem charger to do
lithium-ion batteries. The 4734s work well on Nicad and NiMH batteries only. Don't mess with lithium
ion charging by using an incorrect charger.

Thanks
J