Cruising Without Alternator (Temporarily)

[theway]

My alternator recently died and was wondering how long a starter battery can last if only used for cranking the engine? I have the Bluetop D34M. I’m curious about two situations...

1: (Curiosity) If the starter battery was only used for cranking and never charged. How many cranks could it do?

2: (Actual) If the starter battery was charged some from 2 - 100watt solar panels.... I have 2 House banks fed by 2 - 100watt solar panels (one per bank). That power can also be sent to the starter battery when the starter battery switch is on. My general power needs are low and easily met with the solar, my concern is starter battery draw from each crank.

(I’m in Indonesia and would like to make it to Singapore if possible, but that would be about 1,000 miles and about 60 days. A few moments ago I created a separate thread about trying to source a Balmar Alternator in Indonesia. )

Thanks,
austin

[GILow]

Depends on a few variables, such as how easy the engine is to start. So on paper, I'd say ten or more times for a healthy battery and engine in your warm climate.

HOWEVER, most engines still draw current from the battery when running to power the fuel solenoid/shutoff system, the instruments, maybe the blower fan.

Also, needless to say, as the charge gets lower you risk damaging the battery by leaving it discharged, somewhere around 50% seems to be the critical point.

In your situation, I'd invest in an extra small panel and regulator, another 100 watts would be good if possible, and leave it connected.

Or see if you can get your hands on a battery to battery charger, though I think a "real" one would cost more than the panel and regulator. Simply connecting the battery banks is rarely as effective as we'd like. (I learned this the hard way.)

[nwdiver]

Lots of buses in Indo......get a used bus alternator, or even a car alternator for the short term...also they repair EVERYTHING in SEA.....cost to repair may be cheaper than a used one.

I don't think you want to be anywhere near the busiest shipping lanes in the world without the ability to start your engine, just my opinion.

[GILow]

Another thought... maybe just a solar regulator that handles twin battery systems.

My Votronic regulators have an extra output for the engine bank that keeps it topped up but gives priority to the house bank first. Of course I can't actually use the circuit because the engine is 24 volts while the house bank is 12. But it's nice to know it is there as I can chop the engine bank to charge one battery from each regulator if I need to.

[smac999]

The battery also powers gauges, fuel pumps. Etc.

I would not run an engine or move a boat without an working alt. It is very important. Fix it.

[theway]

Alrighty, all good responses. Thank you. Looks like I’m staying here until I find a replacement. Or at least spend more time to see what my options are.

[Sailmonkey]

Originally Posted by smac999

The battery also powers gauges, fuel pumps. Etc.

I would not run an engine or move a boat without an working alt. It is very important. Fix it.

That’s a little extreme.

If I was in the OP’s shoes, I’d probably pull all of the gauge backlights, and carry on like normal with the house charging the start battery. No biggie.

[theway]

Originally Posted by Sailmonkey

That’s a little extreme.

If I was in the OP’s shoes, I’d probably pull all of the gauge backlights, and carry on like normal with the house charging the start battery. No biggie.

Now you’re giving me confidence. The gauge lights are all on a switch and rarely use because I mostly travel by day.

I have started the engine 4-5 times now to diagnosing the problem and the voltage on the starter battery is at 100% about 12.8 on the meter.

I’ll see what my options are maybe delay a few days to see what I can find, if not I’ll carry on.

I do have a gas generator for a charge if it would come to that.

[theway]

Maybe worth noting that my 2 house banks consist of 2 FullRiver dc224-6v (224 AH). The CCA on those batteries is 900. Which is actually more than my BlueTop.

[Jim Cate]

You say the alternator "died". What really happened? Most alternator ails are repairable, many quite easily, and as mentioned above, finding able repairers is usually pretty easy in third world areas such as Indo. That might well be the quickest and surely the cheapest alternative.

Meanwhile, do some simple maths: Most healthy small diesels start with < 5 seconds cranking. So, if the starter draws the nominal 200 amps (conservative), it will consume 5/3600x200=~0,25 amp-hours per start. Should give you an idea how many repetitions your battery will be good for.

Jim

[Dsanduril]

You didn't specify the engine. Most older diesel engines don't require electricity to run. If you can live without the instruments you can possibly disconnect the battery once the engine is running, it does depend on if you have a stop or fuel solenoid that requires power or an electric fuel pump somewhere in the system. Even our new Volvo/Perkins engines will run without electricity, so it becomes a risk question (how likely are you to miss a low oil pressure alarm?). Personally I'd be comfortable with that scenario for the voyage you mention, YMMV.

Option B is to find a cheap automobile alternator that fits, and carry that as a spare once you get the Balmar fixed/replaced (we carry a stock 35A alternator with the same foot/pulley setup as a spare).

[RaymondR]

Originally Posted by Jim Cate

You say the alternator "died". What really happened? Most alternator ails are repairable, many quite easily, and as mentioned above, finding able repairers is usually pretty easy in third world areas such as Indo. That might well be the quickest and surely the cheapest alternative.

Meanwhile, do some simple maths: Most healthy small diesels start with < 5 seconds cranking. So, if the starter draws the nominal 200 amps (conservative), it will consume 5/3600x200=~0,25 amp-hours per start. Should give you an idea how many repetitions your battery will be good for.

Jim

And the only two warning indicators you really need are the oil pressure and water temperature and they will only come on if there is a problem.

If your diesel has a mechanical engine mounted lift pump rather than electric the engine should not pull any electrical power when running.

Unless you actually burned it out, in which case there should be soot everywhere in the engine box, the most likely culprit for a non producing alternator is a bad regulator.

Some rergulators have brushes on them and you can run a wire from one of the brushes either to the battery or to ground through a resistor and get the alternator to charge. I have used 12V light bulbs for this but you need a volt meter on the battery and watch to ensure the battery voltage does not go above about 14.5 V.

[theway]

Originally Posted by Jim Cate

You say the alternator "died". What really happened? Most alternator ails are repairable, many quite easily, and as mentioned above, finding able repairers is usually pretty easy in third world areas such as Indo. That might well be the quickest and surely the cheapest alternative.

Meanwhile, do some simple maths: Most healthy small diesels start with < 5 seconds cranking. So, if the starter draws the nominal 200 amps (conservative), it will consume 5/3600x200=~0,25 amp-hours per start. Should give you an idea how many repetitions your battery will be good for.

Jim

The alternator is an old Balmar 9 series and based on the photos I sent to Balmar to help asses the problem, he suggested that it’s 20+ years old. More accurately he said it went out of production 20 years ago.

The story is: I left the boat for 4 months and on return it would not charge the batteries. The readings at the regulator are accurate which suggests wiring is fine, so I did the test to see if any magnetism comes from the pulley bolt/nut and got nothing. It seems like a good time to replace it.

As for the math, thanks.
What is the 3600 in the equation?

(And for the record the engine usually starts right away, definitely less than 5 seconds)

[theway]

Originally Posted by Dsanduril

You didn't specify the engine. Most older diesel engines don't require electricity to run. If you can live without the instruments you can possibly disconnect the battery once the engine is running, it does depend on if you have a stop or fuel solenoid that requires power or an electric fuel pump somewhere in the system. Even our new Volvo/Perkins engines will run without electricity, so it becomes a risk question (how likely are you to miss a low oil pressure alarm?). Personally I'd be comfortable with that scenario for the voyage you mention, YMMV.

Option B is to find a cheap automobile alternator that fits, and carry that as a spare once you get the Balmar fixed/replaced (we carry a stock 35A alternator with the same foot/pulley setup as a spare).

Very good points, thanks for the input.

The engine is a Yanmar 3GM30F (mechanical fuel pump unless I’m mistaken). I do have the ability to turn off the starter battery completely with a switch. I’ll definitely run some test to make sure nothing is drawing from it and monitor it often.

I’ll spend a few days looking and see what’s available, but I’d definitely prefer putting the replacement Balmar in as my hopes are the wiring is very similar if not identical vs making changes that I’ll have to undo/modify later. I’m also not the best electrician so it would be nice to be somewhere with possible help.

[Wotname]

Originally Posted by theway

......
What is the 3600 in the equation?

Converts seconds to hours (i.e. 60*60=3600)