Navara not charging

[BluNav]

I have a D22 zd30 Navara and I brought a 100amp alternator off eBay just over a year ago and in the past couple of days the voltage drops down to 12.3volts and after a while it comes back to 14.2 volts. On the weekend it dropped down to 12.2 volts so I tried 5 different alternators and 2 batteries and still 12.2 volts I rang an auto electrician he told me to take the car to him so I put back my alternator and battery and when I drove into the auto electricians driveway it came back to 14.2 volts the auto elect tested it for 1.30hrs and couldn't find anything wrong with the car and it happened again this morning
I need help
Thanks David

 

[happy john]

G'day David, check and clean all the earths and connections for a start.

 

[Old.Tony]

You posted on another thread (here) with a little more information, so I'll include that here.

If your original battery and alternator are performing fine, I would put both of those back in the car and then change just ONE of the items and look at the result. Once you get a failure, you'll know which is the faulty item. Always take care to ensure that the electrical connections are viable - as John points out, they're vital. It pays to follow the negative lead to the engine block and examine that connection too.

 

[BluNav]

I replaced the alternators first then tried the battery's and was still 12.3 drove down the road and it came back to normal. To day on the way to work everything was fine on the way home it does it again I pulled over checked the charge rate and it was 12.2 checked the signal wires that are in the plug that goes into the alternator and same voltage changed alternators and same issue still need help

 

[jonney]

does the little battery charge light in dash stay on or go out when the engine starts up ??

 

[BluNav]

Ever since I put the 100 amp alternator in it stays on till the volts drop under 12.2 then the light goes off

 

[Old.Tony]

What happens to the battery if you disconnect the battery from the car and put a decent charger on it (until full), then attach two 100W driving lights and leave them attached for 30 minutes, then remove them.

What SHOULD happen: a full starter battery in these cars holds about 70Ah of power. A decent charger will charge it to 100% capacity (12.8V). Half an hour of 200W (about 16A) should only consume about 8Ah of power bringing the battery down to about 12.7V, 12.6V at the worst.

That's a home-made load test. If your battery drops below 12.6V the battery is faulty so it MUST be replaced before you try diagnosing the alternator.

 

[BluNav]

Thanks Tony
I will try it tomorrow

 

[308bever]

how old is the battery?

 

[d22dave]

Ever since I put the 100 amp alternator in it stays on till the volts drop under 12.2 then the light goes off

Light should go off after start up. Have you made a typo, or have you put a wire on wrong

 

[BluNav]

Is there a earth strap attached to the exhaust or to a bracket that attaches to the exhaust

 

[jonney]

sounds like it discharging not charging.