Electrics question for the forum sparkys

[steviewhitts]

When I turn my webastospacher on with the engine running the revs drop dramatically to the point that, on tickover,I wonder if it is going to stall.
I have two battery banks. One for engine starting and another for domestics. This occurs when either or both bansk are connected I dont have a volt/amps meter on board but the Beneteau charging state lights are showing the batteries as a healthy 13volts.

Does this sound like a voltage regulation issue or an alternator/charging issue?

The Eber doesnt come on fully when the engine is NOT running which I expect is due to insufficient volts but I thought it should be ok wth the engine running?

Its getting cooler and SWMBO is muttering about requiring heat !!

Thanks in advance
Steve

 

[savageseadog]

Heater will generally put a circa 10Amp load on 12volts. I wouldn't descibe that as a heavy load for an engine driven alternator so I can't be sure what the problem is. Sounds like one or both of your batteries is U/S is my best guess. Only way forward is to invest in a cheap mulimeter and see what voltages you have.

 

[Alex_Blackwood]

Witout seeing the kit I would say that you possibly have a fault on your heater. I assume that it has worked previously?
Anyway sounds as though the heater circuit is drawing a very high current putting a high load on the alternator and thus the engine. When the engine isn't running the load on the batteries will cause the voltage fall due to high current drain.
Could be anyhing but I would suspect a short or partial short circuit, start by looking for damage to the wiring.

 

[pvb]

Fuse?

[ QUOTE ]
Anyway sounds as though the heater circuit is drawing a very high current putting a high load on the alternator and thus the engine.

[/ QUOTE ]There should be a fuse (say 20A) in the wiring loom, so the load on the engine can't be that high or the fuse would blow.

 

[Chris_Robb]

Ran my Eberspatcher yesterday for the first time since fitting a battery monitor. The amps on start up was 20 amps at 12 volts. Battery voltage dropped from 12.6 to 12.3 during this process.

On a small engine, I think this would be noticed. On my 43 hp Volvo - the charing circuits coming on will be very noticable on a fast idle (at around 45 amps). So I think that the poster has a perfectly normal situation. However he should be able to start the ebespatcher without the engine running, so he need sto look at what the voltage is at the ebespatcher whilst it is starting up. Problems may be in to light a wire, corrosion in a joint, or a battery that is not up to delivering the power, though on this I think he would be experiencing other problems.

 

[johnalison]

Not really an answer to your question, but as I understand it, an alternator won't give much current at idle and when I want to protect my batteries, e.g. when using the anchor winch I rev up to about 1400 rpm to reduce voltage-drop.

 

[Anonymous]

These heaters draw a high starting current then fall back to a much lower level. Many installations require the engine to be running to get the heater going but usually after five minutes of so, you can turn the engine off.

It sounds as though your wires are too long or too thin or have bad connections and/or your batteries and their connections and/or the charging is not up to scratch. 90% certainty this is a voltage problem but you need a meter and bit of electrical knowledge to sort it out. Ideally buy one of the boat electrics books and spend an afternoon with a meter sorting it out. It's highly unlikely that anyone is going to be able to pin point your problem here.

 

[halcyon]

If you start the engine with more revs, does that work better?
At tick-over you have very little engine power ( try it with your car, put it in gear, let out clutch ) and it sounds like the engine stalling due to alternator loading.

Brian

 

[steviewhitts]

Thanks for all the responses. I have tried it with the engine running at c.1500 revs and it does the same. I'm not sure of the age of the batteries but I sense a day down on the boat with a voltmeter coming up!
I'll keep you posted.
Steve

 

[Trundlebug]

With your engine running your battery voltage should be nearer 14v than 13v. With a small engine it's quite normal to expect the engine revs to drop when you're taking that sort of power from it. A similar thing happens in small (1.0L petrol) cars when you put on the heated rear screen, headlights and blower.
Forget checking cables etc, I would be more inclined to have a look at your charging system. That would explain why your heater won't come on without the engine running.
The initial high current requirement when the heater is turned on is to work the glow plug and get the fire going. Once it's alight, just as in oil fired central heating, the glow plug is no longer required and the only power required is to run the fan, and maybe fuel feed solenoid.

When charging, your batteries should be reading at least 13.8v. At rest, they should settle to at least 13.0v
Less than this, your batteries aren't fully charged - and you won't get very good performance from any of your electricals. Your battery life will also be shortened.

 

[pvb]

Sure?

[ QUOTE ]
When charging, your batteries should be reading at least 13.8v. At rest, they should settle to at least 13.0v

[/ QUOTE ]Sure about that? Most authorities quote typical open circuit voltage of a fully charged battery as 12.65v (wet lead-acid) or 12.75v (maintenance-free).