Manifold Pressure

[onetrack]

A damaged, sulphated battery with low voltage can damage an alternator. The alternator will run at maximum output continuously, trying to recharge the battery, which is in effect, shorting out the alternator output.

The alternator will overheat, and more than likely suffer from damaged stator windings, or suffer from damaged rectifier diodes, or suffer voltage regulator damage.

New replacement alternators often come with a warning to ensure your battery is in good condition, otherwise the alternator warranty may be voided.

[Moneybox]

There's no way of telling if the generator/alternator ever worked since I got the plane. It hasn't been used enough to tell and the generator light operates as if it's charging.

[onetrack]

Quote

I bought the battery new so about a year old but until completely flattened over several days it remained fully charged. It recharged fully after that so I'm hopeful the battery is ok. It may even improve with constant use.

I've had near-new batteries that were flattened to a very low voltage, and which showed full charge after extended charging - but they would not sustain substantial starter cranking effort - in effect, they were stuffed from being totally drained, and they showed all the signs of being sulphated.

 

However, the AGM batteries are recognised as being much more capable of handling deep discharge, than the regular flooded cell batteries. But a battery load test is the best way to tell a batterys health.

[Moneybox]

24 minutes ago, onetrack said:

I've had near-new batteries that were flattened to a very low voltage, and which showed full charge after extended charging - but they would not sustain substantial starter cranking effort - in effect, they were stuffed from being totally drained, and they showed all the signs of being sulphated.

 

However, the AGM batteries are recognised as being much more capable of handling deep discharge, than the regular flooded cell batteries. But a battery load test is the best way to tell a batterys health.

I can carry out a load test once charged however that is not going to fix the alternator/charging problem. I have no doubt the battery may have lost some of its ability to supply a full discharge however it did fully charge after it was flattened.

 

After I'd left the master on and found the battery flat it was fully charged. I left it at the door of Northam Air Services with a note requesting to have it charged. I picked it up a month or so later and it cranked the engine as if fully charged, not the sign of a stuffed battery.

Edited 3 hours ago by Moneybox