2000 Mazda B2500 still getting low voltage to battery after battery and alternator change and double checking alternator voltage output twice 15amps?

Answer 1

I will be honest I am not fluent with the yr model however the electrical voltage and wiring and charging and output I am!I would try by cleaning the ground wire from the battery to each point it connects.I would also take a meter to check with the truck (key off) and check for a parasitic draw.That means like is your dome light staying on,or if the radio is aftermarket version may be draining the battery as well.If the terminals or rather the metal connectors on the battery positive,and the alternator connectors are clean,no corrosion would reduce the charging of the battery.It would only seem to me it is a bad ground overall,And would remove the each connection for the ground cable from the battery to each point clean it with a wire brush,and tighten.Unless something electrical such as the radio head unit (aftermarket versions) is drawing amps and draining the system,or this model has something else that draws current dome lamps,door switch not all the way in but pulls enuff to drain it down I do not know.Being you changed the two items would point to bad ground connections,or a parasite draw over time draining the system in most cases or even a weak battery cable,alternator wire or wires.Hope this helps.