Alternator

LURCHER · 05 June 2012, 13:11

I wonder if any of you can answer my question , in simple terms do alternators get tired and produce less charge ? Mine shows 14v on my GPS display but the batteries never seem to really get charged fully . I was under the impression that an alternator either works or not .

Erin · 05 June 2012, 16:25

What makes you say the batteries aren't getting fully charged. More likely they are sulphating than the alternator failing.

LURCHER · 05 June 2012, 16:37

I had them charged (2x110ah) after the winter by our local agricultural engineers
and they started the engine so briskly but have never sounded like that since and struggle to get her going sometimes .

jyasaki · 05 June 2012, 17:54

Could be due to several things: Resistive connections between motor and batteries, degraded cables, degraded batteries.

If you know what your alternator was putting out before (while running) jump a new(ish) battery in and recheck voltage.

Have current batteries load tested at an auto parts place. Should tell you what condition they're in.

jky

captnjack · 05 June 2012, 19:05

Not hearing/seeing what's going on, batteries might be fine. Could have a starter, fuel or spark issue...

LURCHER · 06 June 2012, 18:55

It's a 6 cyl diesel so spark not a issue I know that volvo needs a good voltage to power the ecu in the start up mode . After the initial start subsequent starts all day are instant and will carry over to the next day ,but leave it a few days and it cranks away rather slowly and sometimes needs a snort of easi start!!

Hightower · 07 June 2012, 16:58

Start her up and check voltage at the battery and the voltage at the alternator, that will at least tell you if you have voltage drop or not between the two. Obviously if you do get significant drop then your problem lies with the connections/cables/batterys.

If not and your voltage is low at the alternator connection then there might be a problem with the alternator. Your belt isn't slipping at higher revs is it? So worth doing a belt check too.

Just to expand what Erin was saying. You get a sulphated battery if it's left for a time on low charge/discharged, so it's important to get a fully charged battery.