Problems with new Volvo D1-30

richardbrennan

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Sorry I put this on the wrong forum.

You might recall me posting on this topic before, I was having starting problems with a newly installed Volvo D1-30 which appeared to be solved by changing the starter motor. It now appears that I was prematurely optomistic as although the problem has become infrequent it still happened a few weeks ago on a particularly cold morning when the engine had been standing for several days.

What happens is that the start sequence appears to be proceeding normally with the blower coming on when the panel is switched on and the glow sequence is also normal, but when the start button is pressed the panel goes dead and the sequence shuts down almost immediately. What appears to be causing this is a low voltage although the Volvo agents who did the installation appear very vague about whether this is normal on this engine or a fault. If the domestic batteries are introduced into the circuit via the link switch, the engine then starts, pressumably as they help to hold the voltage up.

The start battery is a 105 amp AGM starting battery with thin plates designed for short duration high demand, the domestic batteries are 2X110 amp AGM deep cycle batteries with thick plates. all the batteries are four years old and have been load tested and found OK.

The suspicion is therefore falling on the cabling, the batteries are under the port settee in the saloon and the battery master switches are under the navigators seat at the chart table which is at the rear of the saloon on the starboard side. I estimate the cable run to be about 10 feet. The cable from the master switch to the starter motor goes through the heads around the rear of the engine and back to the starter motor which is on the port side, I estimate this run to be about 13 feet, and finally the cable from the batteries to the earthing point on the engine is about another ten feet. The cable is 4 AWG and I have been advised that this is inadequate for a run of this length and the best solution would be to move the batteries. However, this would be a major undertaking and not something I could consider lightly.

When I started the engine from cold this morning the voltage across the starter motor dropped to less than 8 volts although the battery was fully charged, but the engine did start without any difficulty. I am therefore inclined to think that a fairly modest increase in the starting voltage, whilst not the ideal solution, would probably be enough to eliminate the problem. I am thinking I might therefore go up two sizes in the cables on the engine side of things to 1 AWG and the same with the earth cable to the engine.

My question is would this be adequate and give a worthwhile gain and what thickness of cables are used for bow thrusters which must have the same problem; I would also like a definitive answer as to whether the shutdown of the starting sequence is a feature of some protective circuitry in the D1-30 or a fault?
 
I think that you have self diagnosed the problem. What essentially you are saying that if you use the "all" option on the battery selector switch the extra boost from the house batteries allows the engine to start.
This indicates to be either a problem withe cabling, or the battery itself. As your Volvo is new, I assume you have had another engine before the new engine, and presumably it started OK. I think it is a starter battery problem, probably a dodgy cell. I had a 3.2 Mercedes car which one day was starting perfectly. The next day stone dead. Certainly my starter battery on a 4 litre diesel engine is still above 12 volts after cranking. 8 volts sounds far too low
 
Pappaecho - the the low voltage is very transient and after starting it quickly recovers to 12+ volts. The battery was load checked by the mechanic who installed the engine and appeared OK and I have since had it checked by the original supplier who di various tests over two days and again pronounced it OK.

Davidej - moving the master switches to the aft cabin might be worthwhile, I will look at this when I am next down on board, but it would still be a major job compared to changing the cables.
 
You want these cables to be as short as possible and In your position I would be looking to move the master switches. Upgrade the cables by all means and it may cure the problem but if I was going to do that I would want to shorten them as well. Shorter cables = less cost as much as anything else.
 
You want these cables to be as short as possible and In your position I would be looking to move the master switches. Upgrade the cables by all means and it may cure the problem but if I was going to do that I would want to shorten them as well. Shorter cables = less cost as much as anything else.

I agree, you can have long cable runs, but you need monster cables to carry the current. I had this once on a bow-thruster. The batt had to be put a-midships and the cables to allow the power to be maintained were huge in comparison to ones needed when the batt was next to the motor. I am sure there is a cable calculator that can work it out and yes monster cables are not cheap and can be awkward to hide.
 
Thanks to all for the comments. What I find difficult to understand is why the previous engine, a Volvo 2030, never suffered from a this problem.
 
Just had a quick wizz through your posts.

Some observations , comments and suggestions ... make of them what you will.

If I read the tech specs correctly the D1-30 has a more powerful starter motor than the MD2030 (2kW vs 1.2kW) Presumably it therefore draws significantly more current when cranking. Maybe part of the problem

You say the battery cables are AWG 4 and the lengths you quote seem to total about 33ft or 10m. AWG4 has a resitance of 0.8 ohms/1000m so 10m will have a resistance of 0.008 ohms. If the cranking current is 200 amps then this will cause a volts drop of 1.6 volts....... a bit on the high side perhaps.

AWG 1 has only half the resistance so would only result in half the volts drop.

But before going to the extent of changing the cable it would be wise to check all connections, condition of all crimps and condition of isolator switch. Ideally try to get some idea of any excessive volts drop at all these points ( I once soldered all the crimps on a set of leads to solve a volts drop problem).

All these things could be adding up to cause your problem rather than any one of them being the single cause.


I suspect the reason various things seem to shut down when you try to crank the engine is that they are relay controlled and the volts are simply falling to the point at which the relays are opening.

Unfortunately I cannot locate a wiring diagram for the D1-30 ... always useful when trying to figure out problems.
 
VicS

Thanks for the comments, your information on the starter motor is most helpful in explaining why I now have the problem. It's difficult withjust one voltmeter to get a like for like comparison, but in the case of two starts in short succession, albeit when the engine was warm and the voltage drop a lot less, the minimum voltage at the battery was about two volts higher than the reading across the starter motor. All the connections and switches have been checked, it really does seem as though the cable run is the most likely suspect.

I think in the longer term, moving the switches to the aft cabin is probably the easiest solution as this would shorten the cable runs considerably. In the short term beefing up the cable would be at least a step in the right direction. Anybody know where you can get cable at a reasonable price?
 
Dear VicS

I checked the Furneaux website and the cable appears to be a single strand of copper compared to the multistrand offered by Merlin Equipment. It's certainly cheaper but do you know the pros and cons?
 
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I was just going by the illustration on the website; that of single core cable is clearly illustrated as multi-strand but not the battery cable.
 
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