- This topic has 14 replies, 6 voices, and was last updated 4 years, 8 months ago by
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Good day 424 ‘ers,
I am perplexed by some starting battery/circuit issues I am having. I will preface this by saying, a couple of years ago, I modified the starter battery setup as supplied by the PO. He had two (2) starter batteries, paralleled, beneath the aft bunk (at the compartment at the aft end of the aft bunk). Both these batteries were 1000 MCA. Figuring this was a bit of overkill, I removed one of these batteries. It is this way to this day. Seemed to work just fine, at least at first.Fast forward to present day: I am getting insufficient power to the starter, intermittently, from the starter battery. On these occasions, I parallel the house bank to the starting bank and it cranks just fine. Actions taken to date:
1) Replaced the battery with a new WM 1000MCA. Problem persists. Had the battery checked on three different load testers and it checks just fine. One of these testers was the old fashioned type that many trust as more reliable than the newer solid state models. Appears the battery is ok.
2) Had the starter rebuilt by a reliable rebuilder. Twice. Second time added a new bendix and solenoid. I think for the second time. Again, problem persists.
3) Thoroughly checked all wiring and connectors. Removed connectors sanded to bright, and replaced. No help.
4) Reviewed the paralleling and battery charging circuitry. All appears well, and when the engine is started or vessel plugged to shore power I get 14.25 V, or so, at the starting battery.
5) Monitored operation of the isolator/combiner. Seems to work. It is an older WM 150 combiner. Lights green when allowing charging current, and the solenoid ‘clicks’ and light goes out, to isolate the start battery, when house volts drop to about 12.9. Fires back up when house voltage exceeds 13V (or so).Suspicions:
1) I need more than 1000MCA for my Westerbeke 58. Doesn’t seem to me it should take more than this. But maybe I’m wrong. What are you using?
2) Maybe my combiner/isolator is not isolating soon enough. Perhaps it should be stopping flow of current before house voltage reaches 12.9V. Doesn’t seem to me that this is likely the problem. Seems to me 12.9V on an otherwise healthy and adequate start battery ought to be sufficient to turn the motor over and start the engine.Anyways, if any of ya’ll have any thoughts on this I’m all ears. I haven’t tried manually isolating the start battery via the manual isolation switch. Yet. Will give this a shot when I’m out next week
David
Blue Moon, #189 -
David
I had a similar problem with our Westerbeke 63.
If the engine was cold, the single start battery started the engine without complaint.
If the engine was hot/warm, the single start battery complained and frequently wouldn’t turn it over fast enough to start. If I combined the house bank with the start bank… bang.. the engine quickly turned over and started.
I went thru many of the same steps you’ve taken without any improvement.
I paralleled a second start battery and haven’t had a single issue since…Rick
Eclipse #73 -
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I failed to address Rob’s question regarding the wire size from the starting battery. Can’t tell you the wire gauge number Rob, but it’s standard size for ‘battery to starter’. Same size as the wire that runs from the house bank to the starter (used when ‘paralleled’), and the run for the starter battery circuit is shorter. Runs from the aft compartment under the aft bunk, out the aft bulkhead and into the engine bay area. Maybe 4 foot run, many be 5.
David
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Two things
One is to check voltage drop at the battery cable connected to the starter. Before and during cranking. Put meter on positive cable (Red lead) at stater and the black lead on ground cable at the engine And/or just the case on the starter.Two: remember that the starter uses the engine block as a ground or return path. The block where the stater Is attached (the bolts) must be clean and free of corrosion.
So make sure your engine ground cable is shiny and bright.Please post results.
Alan
Unabated #140 -
Good tips Alan. Indeed I should have mentioned the voltage drop issue. Voltage drop on the start circuit during start is significant. At least when the problem occurs. Appears the combiner isolator ‘isolates’ at about 12.9V. So beginning with 12.9V I hit the starter and volts drop well below 10. Around 9. I know, not good. But then later, when Volts on the house come up a bit; say to 13.1, and the combiner starts letting power flow to the start circuit, the start circuit works fine. Volts drop to about 10 during the cranking and the motor fires right up. I’m told by my starter rebuilder that 10 is ok.
And I did polish all contacts, including the starter face where it contacts the ‘bell housing’ and the face of the bell housing. The bolt itself looks good, and I polished both the washer and the terminal end itself until it shone. I use sandpaper. And of course the same ground circuit works just fine when the house battery circuit is paralleled to the start circuit.
So the perplexion continues. I’m going to manually isolate the start circuit on my next overnight trip, in a couple of days and see what happens. My current thought is, assuming the battery is ok, and the starter is ok, and connections of wiring is ok, then it must be the combiner waiting too long to isolate the start battery from the house.
David
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That’s a really serious voltage drop. I’d worry about about the potential for fire with that type of voltage drop and amperage.
I would replace the two wires for the starter with new 3 or 4 gauge (or bigger) tinned wires just to be eliminate the possibility that corrosion hasn’t worked it’s way up the copper on the old wires.
Check to see the amperage rating on the combiner. Some of the smaller ones are really light duty. You shouldn’t need your house bank to start the engine unless the start battery is bad. I have an average sized car-type starter battery and it’s worked fantastic for my Yanmar starter (and Westerbeke 60 when I had it).
Trace your grounds to all batteries, engine, and grounding system in the locker carefully. When I was doing my repower, I forgot to reconnect the wire from the main grounding panel to the batteries. I was wondering why I was getting such bad voltage drops on all of my electrical systems. Found out that the current was going through a really small wire in lieu of the one I forgot to reconnect that eventually connected to the battery ground. This wire was really, really hot. Glad I found that one.
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Good point on the wire size. The older Pearson’s used welding cable for this stater and battery hookups.
I’ve replaced all of mine with marine rated cable.
If you need to replace cables.
Use genuinedelz.com. They will make custom cables for any size any color. Good quality. Crimping and sleeved. I just ordered a 2/0 6 foot with 3/8 connectors. For 49.00 free shipping no tax. Got it in 4 days -
For 12 volt system. With 3% loss
And a 100 amp draw over 10 feet
Would require 4/0 cable.A good starter will normally draw 60 to 150 amps with no load on it, and up to 250 amps under load (while cranking the engine). The no-load amp draw will vary depending on the type of starter. If the amp draw is too high, the starter needs to be replaced.
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Good tips guys! Thanks. I will advise when I get this fixed!
Did this get resolved? I recently re-did my house battery bank in LiFePo4 and am now working on the engine start battery bank. The PO had a bit of a crazy setup. Did you add a battery to make it work? Seems nuts that the starter needs more than a 1000 CCA battery.
I replaced with one group 24 and no issues starting engine. W58
They make G24s up to a 1000A CCA if its a pure starting battery. Do you know your batteries rating?
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Bryan Bywalec
S/V Pelican, Hull 209
Siren Engineering, LLC -
Ok, we did some testing. A single Group 24 550 CCA battery wouldn’t start my W58. In fact the voltage drops so significantly that the current welded the starter solenoid contacts in place and it would every so slowly crank even after the ignition key was off. Had to disconnect with the battery switch. A testament on why you should fuse your battery cables.
Then we tried two group 4D 1000 CCA batteries in parallel. Fired right up. At least there is an upper bound.
Tried one group 4D 1000 CCA battery and it took a slow crank before firing up. The scary thing here is if the voltage drops too low are you going to weld the solenoid shut again?
Used 1/0 cables, with grounds two both sides of the engine. The batteries are pretty old and have seen some service.
I’m off to get some fresh group 24 1000 CCA batteries and will test one and then both.
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Bryan Bywalec
S/V Pelican, Hull 209
Siren Engineering, LLC -
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