Originally Posted by
Hindin
Hmm! The siren module contains two 3.6v 140mAh NI-MH batteries. I just assumed that because they were NI-MH batteries that they were rechargeable. Which begs the question if those batteries are rechargeable and near the end of their lifespan and take longer to charge will that cause excessive drain on the car battery?
It depends on how the charging circuit in the Siren Module is designed. A charge current of a few (5 or 10) mA is no big deal. But if the circuit is poorly designed, (not current limited) then sure, it can be a cause of trouble.
Of course, there is certainly a current limiting resistor (at the least) involved,
A battery rated at 140mA (I assume that's 140mAH) should have a charge limiting circuit on it of less than ten mA.