My 1999 malibu won't charge. ihave checked ground at battery,replaced alternator and battery still only getting 11.8volts at battery?

Check battery!

If voltage goes below 9 then battery needs to be charged

If headlights go very dim during crank battery needs charge

If after charge same result replace battery

Hope this helps?

Hotrod, Recheck,clean and tighten all connections. If you say you had new alternator tested and is working OK, the new battery must be defective. With the van running, use a DVO meter and check the battery, if it shows above 14 volts then the alternator is OK, a good battery should show 12.4, that leaves either a faulty battery not holding a charge or you have a parasitic draw(something draining battery). Which would have to be diagnosed by a good Tech.
Check the attached links,instruction and guides, Good luck
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Can't charge a dead battery--- that is due to be replaced

What was tested & how on alternator

Voltage,Current Output ?

Have to have voltage to alternator regulator from where
ever it comes from

Five bad alternators in a row borders on the incredulous. 2, 3 maybe, but 5 is a Guinness world record! I have to ask the 30 amp fuse made what worse? Is it not charging? Have you tested the battery? Maybe it has a dead cell, won't take a charge. Recheck battery connections and grounds. Test the battery or try a different good battery. What testing tools are you using?

Sounds like you have a toasted battery or alternator. Have you performed a load test on the battery? Have you tried to charge the battery? First remove the battery and charge it externally from the vehicle. If the battery won't hold a charge, or won't hold a charge of 12 volts, replace it. Once you have the vehicle started, test the operation of the alternator. It should be putting out at least 13 volts back to the battery to keep it charged - if it is putting less than 13 volts or more than 16 volts, replace the alternator.

It sounds like you need a new starter. If you hear the starter click when you turn the key to start, replace your starter since you already replaced the battery. You might want to have your alternator checked out, or when you get your car started, test the battery terminals with a multimeter. You should have around 14 volts with the car running. If not, you will need a new alternator. The alternator won't keep the car from starting though, unless the battery was drained because it wasn't charged. Even then it is the battery keeping the car from starting.

If the starter is not clicking, check your fuses under the hood. If all checks out, you may have a bad ignition switch.

I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

it is possible that bran new parts are defective if for sure that it doesnt charge check the wires from alternator to battery if not broken or a fuse in between could be burnt causing a no charge as well the plug in on alternator sometimes break inside the connector so check wires carefully but be sure alternator is good

It could be the generator field from the ECM. The ECM supplies this variable-duty cycle signal to ground the field winding of the alternator. So the alternator may not be getting "turned on" by the computer.

Not enough information. When was the alternator changed and was the battery fully charged before trying to start after installing new alternator. If not the alternator could have burnt up. Have electrical system checked free at Advance Auto.

Check the Voltage Regulator, and how old is the battery, Check the cells in the battery. If battery is 3 years or older replace.