Power Surge

[Wolfe Smythe]

Need help with a power surge issue. Every time I start my engine all of my instruments go out and restart. This is probably not good for the electronics or other systems. Has anyone encountered this and is there a cure.

I was on another site and they suggested isolating the starting battery from the system.

I think there is another issue at play.

I run a high output Balmar alternator with a Maxcharge MC-614 regulator. If that helps.

Thanks

Wolfe

 

[dave_a]

Does your "smart" regulator have a "start feature" where by it does not throw a full alternator field load until the engine is started for a few seconds?
This prevents engine crank wear before oil pressure arrives. A 100 amp alt. puts a lot of load on the belt(s).
The tachometer is fed from Alt output and might explain this anomaly. I do not see how "isolating" the start battery will cure this.
Dave

 

[rolf]

I have the same issue and the isolation of the starting battery is 99% likely the issue. I will be investigating this over the next few weeks but what I've learned so far is 1) the 1-both-2-off switch is not entirely isolating my batteries and 2) if I have my switch on 2 (house) then so is my starter on 2, I can watch the battery monitor when I start the engine. I have the Balmer 100amp and the 612 regulator, stage 1 is a 45 second delay at the start.

See this write-up from "Maine Sail" for a solution I want to implement, to include an automatic charger relay (ACR):
http://forums.sailboatowners.com/index.php?threads/1-both-2-off-switches-thoughts-musings.137615/

I, too, am looking for ideas on this one, a diagram with both negative and positive between all the components (batteries, switches, starter, panel, ground/engine?) would be VERY handy for this electrically challenged sailor.

 

[dave_a]

Wolfe & Rolf, its nearly impossible to figure out why the instruments restart w/o an accurate wiring diagram of Wolfe's boat. In reading Mainesail's article this section jumped out to me as a likely cause:
"Voltage Spikes and Transients". It's likely (my opinion) that the instrument positive (or negative) feeds are not taken from a bus bar fed by a large gauge wire. In other words the positive (or negative) are tapped off an existing circuit.
On my boat for example there were a lot of accessory feeds run from the positive lug of the ignition switch. Some fused, some not. I ran a "sub" BlueSea fusebox and separate positive & negative circuits, fed by #4 battery cable.
Another area to inspect (replace?) is the small negative bus bar aft of the engine, accessible through the quarterberth. Its a likely place to "ground" pedestal mounted instruments. But it grounds at the engine block (small guage) and through the 12VDC return of the OEM panel. Its undersized, subject to salt spray from the shaft packing, and not connected directly to the battery neg. post. Too many junctions points and no direct route to the negative terminal of the house batt. As many have said the M38's electrical systems weren't state of the art in the 80's, less so now with age and corrosion..

 

[jimcleary]

Wolfe
Have you changed anything recently on the boats electrical system? Have you added or removed any equipment? Have these symptoms recently begun after years of working properly? Dave is absolutely correct about the haphazard way the boat were originally wired. The problem may be traced to an undersized negative conductor or a terminal that has recently become loose and is creating a high resistance in a circuit. I would first look at recent changes to the system. Then do some housecleaning by removing, cleaning, coating and replacing connections. Look for the simple solutions first.

Jim

 

[rolf]

Dave, thanks for the thoughts, I will look at my system tomorrow, I probably have original wiring, particularly the pedestal and engine controls and will look for undersized buss bars and negative grounding. I know I also have something funny with the circuits for the 3 switches on the engine panel - bilge, blower and compass - that I need to change, Jeff L helped me identify that when he was aboard and drew a diagram that helped. The whole electrical system is very overwhelming for someone like me who thinks anything with more than 2 wires needs a magician to resolve.

 

[dave_a]

Rolf - no doubt electric troubleshooting can be puzzling. I try to (over?) simplify & think of it as water running in a hose. Poor quality/corroded crimp connections turn into "kinks in a hose", or envision an undersized wire looking like 1/4" hose fed from 2" hose trying to fill a bathtub. It works for me at least.

One bit of advise. Work backwards from the battery. Clean the + & - battery terminals & wires, then follow those wires to their next stop. Clean the next connection, and so on. Sand paper, dielectric grease, and shrink tubing are your friend. Don't be afraid to replace a large gauge (battery) wire crimped end if it's green & corroded. Getting those big wires working right and flowing can make intermittent elec. problems disappear! Chase these big wires back to the buss bars. Then when you have a small wire circuit, with years of crimped on crimped connections (like your bilge pump or water pump) - you can save time and just replace the wire. You can be confident that the path to and from the battery are good.
Most folks can't afford to pay a boat yard mechanic to clean wires. So this becomes a "joy of boat ownership" task.
Dave