Voltage on Start-up

[ealanm]

I'm wondering if the voltage readings I get on start-up are normal. When I first start it's well below 12 V, then climbs to healthy voltage (just under 14) in the first 30 seconds to a minute. I'm fairly confident the alternator is fine, as it's brand new and there are no signs of charging issues -- cranking is strong and the lights are steady at all RPMs. Is the voltage rise just the effect of the glow plugs?

[jessef]

It is normal on all L400's with the stock voltmeter gauge.

[thedjjack]

for that first 30 seconds you glow plugs are most likely still on draw more amps then the alternator can supply. Normal.

[tonydca]

On mine, the glowplugs draw down the voltage significantly, but the analog dash gauge is pretty heavily damped (slow to respond).

If you plug in any kind of digital meter (I have one of those cheapo CT "alternator testers" that are basically a set of 6 LEDs which glow in sequence at progressively higher voltage levels) you can see the almost-instantaneous jump from around 11.5 to around 14 as soon as you hear the loud *Click* when the glowplug relay trips off.

The gauge then takes quite a few seconds to leisurely rise up to indicated voltage level.