D-180 reboots after cranking

B4-METRIC

New Member
Joined
Jun 26, 2011
Messages
4
My D180 shut down when I hit the starter button.  I don't have the battery backup option. Mainly because my battery could run it for days without recharging. To solve the problem I supplied it through a 4 amp diode then put a 10,000 MFD capacitor after the diode. During startup, the starter drags the buss voltage a little low for a split second. The capacitor keeps the voltage up and everything works. For what it's worth to anyone else. By the way it's a Lycosaurus 150 with a 750 cranking amp battery and only a 24" starter cable on a lightweight geared starter. I don't think you get a better system in terms of voltage drop in the starter system. It also did it with no compression ( plugs removed) so it doesn't take much to lower the voltage enough to make the 180 calf.
This works the tip might help someone. I wanted to watch my oil pressure during initial cranking. By the way it shows 30 PSI on the starter without firing.,

Al
 

dynonsupport

Dynon Technical Support
Staff member
Joined
Mar 23, 2005
Messages
13,226
Just an FYI, but while the cap may work for you, it doesn't work because it holds the voltage up while you crank.

If you have a 10,000uF capacitor at 12V and you take 1A out of it, it will be down to 4V in 0.12 seconds.

The D180 shuts down at 6V, so if you wanted to keep the D180 alive for even just 5 seconds while you cranked an engine, you'd need something more like a 1F capacitor (1,000,000uF).

It likely works because you only had moments below 6V when the starter rotated, not below 6V the whole time, and the capacitor caught those very, very short dips.
 
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