Starter from 24V to 12V

Traditional Farmer

Well-known Member
Location
Virginia
Is it possible to change over a starter from 24V to 12V? Bought an Oliver 1250 gas that has a 24 Volt starter and it'd be a lot better to have it 12 volt and do away with the
24V system.
 
This is textbook material as there is too much to it for a response here.

Starters are usually of the series wound type which means current controls the rpm for a given load. If you can get enough current to the starter at 12v you ought to be able to do the job in my guesstimation!!!!!

Question is the DC resistance of the starter windings. Since the current would have to double with the voltage halved, you might not be able to obtain adequate current even increasing the size of your interconnecting wires between the batteries and the starter due to that problem, and doubling the amperage capacity of your batteries by hooking 2 12v batteries in parallel (+ to + and - to -). Course if you are running 24v now with 2 12v batteries in series, you can just hook them up in parallel and the battery part of the problem is solved.

Going to guess that your engine won't spin fast, but strong. By strong I mean that the starter will whir whir whir like when you have a partially discharged battery in a normal system, but unlike that situation it will continue for a longer period.

One thought that just occurred to me is that in starting a Diesel, especially in cold weather, you have to spin it up fast enough to generate enough compression heat in the combustion chamber to get it to light off and that might not occur with a slower spinning starter. Course you could use a heater or starting aid to solve that problem.

What will it cost you to try? A voltmeter and 1 new interconnect cable initially if you are currently using 2 12v batteries in series.

Obtain 1ea. 0 size wire with suitable terminals to jumper between the batteries. Then remove the wire that currently connects between your two series batteries and connect it to the same polarity post on the other battery rather than the opposite polarity post as it is currently. Place the new jumper between the remaining two posts on the batteries......+ to + and - to -. You now have 12v (batteries in parallel) but twice the current capacity from the batteries.......the rest of the circuit is the question.

Get a voltmeter and setup to 20v DC (lowest DC scale on my meter but anything above 12v). Place the leads across the starter, hot lead to starter case (usually). Ensure that your batteries are in good order (not sulphated up internally) and fully charged. Spin the engine and while doing so, measure the voltage at the points mentioned on the starter.....hot terminal to starter case. If you have less than 10v your battery to starter wiring needs to be upgraded. I use size 00 for that on my 100 hp diesel.

If you do, how does it work?

Using a 6 v starter on a 12v system is a no brainer. Spins like crazy and only thing that keeps the starter from burning up is that you are only on it for a few seconds. This is a different situation.

Good luck,
Mark
 
We used to have an auto parts store nearby that had a service of sending them off to the rebuilder to have that done. I had one done years ago and it took about 10 days. That particular store chain has since closed, but I'd bet that a local generator/starter shop would have the information to do it or know where to send it.
 
As Jim said don't waste your money on having a 24 volt starter re-done to 12 volt,,find a 12 volt starter to replace it, your starter shop should be able to come up with one that will work, then go with a 12 volt single wire Delco alternator.
 
Tim S is correct tried that on 3020 John deere won't spin fast enough. Just get 12 volt stuff and you will be happy. Might have to put starter solenoid on neutral start safety switch circuit to get it to work correctly depending on what starter you use. good luck.
 
For about $100 you can put in a series parallel switch for the starter, I still think that is a better solution than a 12V starter.
 
http://www.ebay.com/itm/Series-Parallel-Solenoid-Relay-Switch-12-24-Volt-CATERPILLAR-Cummins-Delco-White/371183067713?_trksid=p2054897.c100204.m3164&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20140407115239%26meid%3D57402be5b68c44f29b7fe853c50bd70a%26pid%3D100204%26rk%3D2%26rkt%3D27%26sd%3D281163535044
 
The governor is on the generator,but I don't know if it does much generating so I thought I'd just run a marine deep cycle battery for now.The switch David posted about probably be the best thing.
 

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