Hi and
to the forum.
24V lithium Ion batteries can be used in place of 24V NiMH but you may need to change the connectors on the battery to suit your existing wiring connection.
Lithium batteries require a specific charger with a precisely set maximum voltage and therefore should
not be used with a NiMH charger.
My 24V LiFePO
4 charger has a maximum set voltage of 29.2V, whereas my 24V NiMH charger has an unregulated output of 39.5V which could easily overcharge a lithium battery
(if the battery's BMS didn't have sufficient overvoltage protection) and if left on charge for too long could even result in the battery bursting into flames.
Alan