24V Starter on 12V Boat

[Audeamus]

Not wanting to be argumentative but:

(You haven't told us type of engine).

However for example starter for a 12v71 weighs 77lbs and costs ~ $600

From Delaware 12" x 12" x 18" 77lb $489 DHL Fedex $559. We have had multiple problems with fedex over the years DHL not once.

Anyway duty on this $110 so total about $1200 all up.

For cat 3408/3412(thats 800-1000hp) weight and price & shipping about half the 12v71.

We use a forwarding/consolidating company "fishisfast" - invaluable in keeping the boat going

If your starter weighs more than 150lbs then you have a point.

[CAPAZ]

allright y'all, I can't stay in the wings any longer without losing face...

this is actually my boat, and yes we are in a bit of fix. We are in Hokkaido, Japan, hopefully heading out to the Aleutians in about 3 weeks We have a Gardner 5 LW with a CAV 12v clockwise starter motor. It appears to be functioning, ie turning the pinion but not enough force to turn over the engine

A bevy of interested and hopeful marina mechanics and a reputable electric shop all looked at it, spoke a lot of Japanese, and finally said how sorry they were but it could not be fixed in Japan. No parts etc

I then contacted the Gardner parts in UK and was told they don't have the 12v for exchange and would need 2 weeks in the shop for a repair, plus shipping time meaning about a month

Now I have found a shop in the UK the does a large amount of starter rebuilds and they say they can get one in the post in about 4 days with a 5 d shipping window. Deposit on our core refunded when old one sent back

all seems good right.... then my mechanic posse shows up with my starter saying it has been repaired although I can't get any details. Looks like they cleaned (it is Japan of course) and spruced up the contacts. Plan for tomorrow is to put it back in for a trial

Not really expecting too much....would almost be more trouble if it sort of works but doomed to failure soon

thanks Kungfoo for all the design work anyway

Rocco

[GrowleyMonster]

Be sure and check your voltage during start attempt. If it is going too low, could be wiring issue. A high resistance connection in either the + or GND side can allow normal operation of lighting and other small loads, but then cause a huge voltage drop when high current is required.

Did you check resistance of windings to make sure that was the problem?

A spare starter is a marvelous thing to have aboard, when you find that you need one. Just sayin. Along with cooling water pump, raw ater pump, alternator, and an electric fuel lift pump oh, and injectors. A diesel engine, especially naturally aspirated, is insanely dependable if decently maintained, but relies on peripheral components that are relatively inexpensive and also more prone to failure than the base engine. The obvious thing then, is to have spares and know how to swap them out.

Ah I see in your last post you have your starter back with a clean bill of health. Looking forward to your trial results. I have seen quite a few bad starter problems that turned out to be battery or wiring problems that only caused issues during engine start attempts.

[OS2Dude]

I did not see this, so sorry if it duplicates a previous answer.

If the alternator can't be fixed and the shipping cost for the proper item is 'not worth it', then make the starter bank 24V. Use a DC-DC converter (buck) to drop it to 12V to go to the panel. Bob's Your Uncle.

You may have to isolate the block from the panel ground. I'm not sure if 12v & 24v can have a common ground.

[boatpoker]

30 years ago I got a brand new 24V thruster for my 12V boat.
I found a dirt cheap series parallel switch at a farm equipment outlet (40) installed two group 24 12V batteries and a $4 relay from the same place.

and it worked fine for the next 16 years I owned the boat. It turns out a very large percentage of farm equipment works this way and any such outlet will have them. You can wire it directly to your ignition switch or to a momentary switch, either way works.

Just another option if you can't get the parts for the other solutions advised.

[Manrico]

Originally Posted by kungfoo

A buddy of mine is currently in Japan and his starter has gone out. His boat is 12V and he's concerned about missing the weather window.

One options we're currently exploring is the prospect of him using an otherwise compatible 24V starter motor.

It looks like there are some decent 12V -> 24V converters on the market that could be used to keep a new pair of 12V cranking batteries charged at 24V, but in case he can't source those I wanted to have an option available to him.

I put together a schematic (attached) of a way that it seems like it could be done using 5 readily-available SPDT relays and two new cranking batteries (even the 12V->24V converter plan involves those batteries).

It may not be the best option, but I am a big fan of getting all the options on the table before making decisions, or maybe just bringing the schematic and 6 (5 + 1 spare) SPDT relays along for the ride.

Would love some thoughts on how best to help him across the Pacific.

Thanks,
Harrison

Edit: I'd probably also have him throw in a battery isolator that can handle a 24V reverse bias as an extra layer of protection to ensure you never blow things up.

Hi, my boat is electric powered by a 48V 200A bank and I use a step down 48V to 12V 30A to power the house, it's simple and works good, I think you can do the same with your 24V bank. Nice regards.

[CAPAZ]

the engine is an older Gardner 5 LW

found a quite good shop in the UK that does rebuild exchanges. "new" one on the way for arrival next week. Am supposed to send back the core for the deposit but the shipping out of Japan will likely be about the price for return on the core about 350 USD

all said any opportunity to get off the dock will be a blessing

[Iains boatyard]

If you have a Gardner engine why you not know about Mainline Diesel in Queensland Australia and Shaw Diesels in NZ both do rebuilds and exchange parts.
I use Mainline great people. He is a Gardner trained mechanic.
Try Google.