How to build you own high torque electric starter
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I was not happy in terms of price and/or quality with high torque starters available on the market and I wonder if there are any "how to's" or anybody tried to build a above average power starter.
I think converting a bike or ATV electric motor starter my be a good starting point.
I'm looking to start gas engine between 50 and 80 cc.
Any info will be highly appreciated !
George
I think converting a bike or ATV electric motor starter my be a good starting point.
I'm looking to start gas engine between 50 and 80 cc.
Any info will be highly appreciated !
George
#2

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Voltage is king when it comes to starter performance, I have set up many portables with voltages and battery types all the way up to 18 and 24 volts. Most starters are rated at 12 volts and at this are pathetic performers but I have used many very successfully at 18 volts.
The only actual starter I known rated higher than 12 volts is the Sullivan Dynatron. This starter is rated for twenty four and is a real performer at that voltage. Here is a picture of my two Dynatrons that I use for certain airplanes and power both in a portable fashion with 18 and a 24 volt drill batteries. One is my homemade gear drive but Sullivan makes excellent belt drive units for the Dynatrons too:

John
The only actual starter I known rated higher than 12 volts is the Sullivan Dynatron. This starter is rated for twenty four and is a real performer at that voltage. Here is a picture of my two Dynatrons that I use for certain airplanes and power both in a portable fashion with 18 and a 24 volt drill batteries. One is my homemade gear drive but Sullivan makes excellent belt drive units for the Dynatrons too:
John
#3

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Well back in the day when racing was still around the number one starter was a home built for the unlimited planes, it was just a 12 volt starter from a Toyota mounted in a box with a 12 volt auto battery. I still have an old one someplace? John is showing you some very good starter choices. A couple of the guys where I fly just have 24 volt drills with the big cone attached. When my G-62s didn't want to start I would borrow one of the drill starters and it zings the engine over very well but almost no one uses a starter on a gas engine. A leather welding glove is a bunch cheaper and almost no one uses them either. A well tuned gasser fires in just a couple of flips.
#4

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One of our locals still lugs around and old auto starter and heavy solenoid big cables and that huge battery. Far better alternatives these days for those of us who choose to use starters.
So George if you do make up something that three inch cup on my geared starter is a three inch hole saw that I ground down and the silcon insert was I believe from Sullivan. I also have a home machined two inch cup that slips over the standard one inch and secured with set screws when the need arises. I think that two inch silicon insert also came from Sullivan but not sure since I bartered for it.
We just had our local Q-500 424/EF-1 race Saturday and during all the practice flying my last 18volt black and decker drill battery went to battery Valhalla. The twenty fours were overkill for the .40 displacement engines But just happened to have a few 5000 mah four cell lipos. Never wanted to experiment with lipos before for the starters because of the deep discharge danger as well as give up a few volts with the four cell and the three cells are just right back to no better than the old batterys we used to all lug around.
Well turned out very well and it worked very well in this application and of course the ability to make several trips to the field without charging is nice. The down side is four cell lipos are not cheap by any means. Since this was a last minute deal I did the simplest conversion yet. I did not want to cut off those oddball battery connectors because I have one airplane that uses those batteries so instead soldered on a pair of insulated alligator clips on the started leads and the alligator tips push into that connectors holes and it works great.
John
So George if you do make up something that three inch cup on my geared starter is a three inch hole saw that I ground down and the silcon insert was I believe from Sullivan. I also have a home machined two inch cup that slips over the standard one inch and secured with set screws when the need arises. I think that two inch silicon insert also came from Sullivan but not sure since I bartered for it.
We just had our local Q-500 424/EF-1 race Saturday and during all the practice flying my last 18volt black and decker drill battery went to battery Valhalla. The twenty fours were overkill for the .40 displacement engines But just happened to have a few 5000 mah four cell lipos. Never wanted to experiment with lipos before for the starters because of the deep discharge danger as well as give up a few volts with the four cell and the three cells are just right back to no better than the old batterys we used to all lug around.
Well turned out very well and it worked very well in this application and of course the ability to make several trips to the field without charging is nice. The down side is four cell lipos are not cheap by any means. Since this was a last minute deal I did the simplest conversion yet. I did not want to cut off those oddball battery connectors because I have one airplane that uses those batteries so instead soldered on a pair of insulated alligator clips on the started leads and the alligator tips push into that connectors holes and it works great.
John
#6

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A lot of the old time racers had those auto starters on wheels so they could be rolled out to the line and they rolled right up to the prop/spinner so no one had to lift them. Torque couldn't be beat though and the OP did ask. My own starter is just a standard heavy duty starter with an 18 volt battery pack that John came up with a couple years back. It's good up to the DLE 30 but the 24 volt is hard to beat. Set one up like John and you won't be sorry.
#7

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A gentleman in Memphis, TN. named Boris Mazor makes a VERY nice starter using a Honda ATV starter & solenoid. He builds a simple, strong frame to mount everything to, with a handle & pushbutton switch. Makes for an well balanced unit, lighter than anDynatron/Makita setup. Runs on either 3s or 4s lipos. A low voltage alarm is an option. I've used the Sullivan Dynatron & the older Model 4 on 24 volts, this thing puts them to shame on 3s/11.4 volt lipos. Belt & cone drives are available. I race rc boats & use it on everything from .21 nitro on up to some VERY high compression 29.5 cc modified Zenoah engines. I have seen them start 52 cc marine racing twins, no problem. I run mine on 3s 4500 mah 25-50c lipos, i can go to a 2 day race, run 4 boats (2 gas & 2 nitro) 4 heats each without recharging. Boris can be contacted at:
[email protected]
[email protected]
Last edited by moparbarn; 07-13-2015 at 12:05 AM. Reason: added picture
#11

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.I still use a starter onbig engines. I value my fingers.
I use a miller persuader mounted on a standard Sullivan starter. Because the persuader has a 3:1 reduction I can use 24 V on the starter.I have started a BME 102 with this.
I have had the miller for 15 years
I use a miller persuader mounted on a standard Sullivan starter. Because the persuader has a 3:1 reduction I can use 24 V on the starter.I have started a BME 102 with this.
I have had the miller for 15 years
#13

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The majority of the marine gas engines still use the standard magneto style, with a pickup coil & a secondary/ignition coil. Standard weedeater recoil starter on the flywheel end. Since these are modified with higher port timings, larger carbs & tuned pipes, they don't start as easily as aero gas engines. On the opposite end of the crankshaft is a collet with a flex cable connecting to the prop. To use an electric starter can sure save your shoulder in our application.
#14

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I have a Sullivan Dynatron on a 6S LiPo. I use this on my YS185 when it's frosty and the 12 volt won't spin it. Haven't tried it on anything bigger, but it has heaps of power.
Also made my own using an outboard motor starter. Evinrude starters spin the right way without having to reverse anything. I use this to prime my SuperTigre 4500 which is mounted inverted. I should really try the Dynatron on it.
I hand start all my gas engines.
Also made my own using an outboard motor starter. Evinrude starters spin the right way without having to reverse anything. I use this to prime my SuperTigre 4500 which is mounted inverted. I should really try the Dynatron on it.
I hand start all my gas engines.
#15
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John,
It appears you are running the Torque Master on a 3S LiPo.
What current rating?
How does it perform?
Have you tried it with a 4S?
I have one I am in the process of converting.
I run my Sullivan on a 4S 2200 and it does a marvelous job on my 40s, 60s and 120 FS
Thanks for the info.
KW_Counter
It appears you are running the Torque Master on a 3S LiPo.
What current rating?
How does it perform?
Have you tried it with a 4S?
I have one I am in the process of converting.
I run my Sullivan on a 4S 2200 and it does a marvelous job on my 40s, 60s and 120 FS
Thanks for the info.
KW_Counter
#16

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Hi KW actually it is 4S 5000 mah and about 40c or thereabouts. Been using 18 volts or more for to long to ever go back to something like ll volts with a three cell lipo. One nice thing this starter I have been using several weeks now and for my usage which is almost daily I have only needed to charge every third day.
Normally I am used to charging the starter every outing just as you would the RC system. For the Dynatrons using six cell Lipo to get it up to its rated voltage would be tempting but also quite expensive.
John
Last edited by JohnBuckner; 07-18-2015 at 12:54 PM.
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John,
How do the 12V starters hold up running them over 12V? I've heard of people incapsulating the rotor windings in epoxy to keep them from flying apart at the higher voltages. How much of a concern, or have you experienced any problems running 12V starters at 18V.
How do the 12V starters hold up running them over 12V? I've heard of people incapsulating the rotor windings in epoxy to keep them from flying apart at the higher voltages. How much of a concern, or have you experienced any problems running 12V starters at 18V.
#20

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Papa If you open up the switchs on any of the cheaper starters you see that the diameter of the contacts is about half the diameter of the more expensive starter and as noted the weak point of using higher voltages in cheaper starters is indeed the switch. What will happen when the load is increased and the current draw goes up the current can exceed what the switch is capable of passing and the contacts weld themselves together causing a runaway starter. Pain in the butt since you have to disassemble the switch and sand paper the contacts.
Now having said that I have tried all manner of batteries on every variety of starter I could get my hands on, cheapest to about the most expensive and I never found any starter/switch that could not handle an 18 volt battery,
John
Now having said that I have tried all manner of batteries on every variety of starter I could get my hands on, cheapest to about the most expensive and I never found any starter/switch that could not handle an 18 volt battery,
John

Last edited by JohnBuckner; 05-16-2016 at 08:18 PM.
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Billpatt (07-06-2022)
#21

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I built my first one hand self contained high power starter at least three decades ago using two 6 cell NiCad RC car battery packs. This was to get rid of the cord and for more power than the then popular gell-cell batteries that would not pull the skin off of warm milk. As pointed out by John, voltage is king, but I would also say as long as you use a battery system with low internal impedance.
The only problem I see with LiPo cells is that they do not like to be left with a full charge. And that whole possibility of burning down your house could be a problem. They also give up the ghost when cold, where you might need the most power from a starter.
So you pay your money and take your chances.
The only problem I see with LiPo cells is that they do not like to be left with a full charge. And that whole possibility of burning down your house could be a problem. They also give up the ghost when cold, where you might need the most power from a starter.
So you pay your money and take your chances.
#22

I have a Sullivan Dynatron that I power with 6 A123 batteries. That gives it pretty good power. When I charge the batteries I am at around 21V. It then slowly drops with use. I am presently at 19.8V and I haven't charged in a good while. When it gets close to 18V I charge. Once, I ran the batteries down until the starter barely turned. I figured I may have ruined the batteries. But they recovered and balanced out good. It is a powerful setup.
#23
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greybeard nailed it. my son and I raced karts for years and the typical starter for most engines was exactly that same thing . it worked on all engines we raced. most were made from outboard boat motor starters because they spun the fastest, being from a 2cycle engine there's lot of DIY info about building them on the various karting forums around the internet.
#24

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I have a Sullivan Dynatron that I power with 6 A123 batteries. That gives it pretty good power. When I charge the batteries I am at around 21V. It then slowly drops with use. I am presently at 19.8V and I haven't charged in a good while. When it gets close to 18V I charge. Once, I ran the batteries down until the starter barely turned. I figured I may have ruined the batteries. But they recovered and balanced out good. It is a powerful setup.
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People finding lithium batteries expensive. Yes, but I use batteries coming from an old laptop computer. You can get or buy several packs from a computer shop for few $ and discard the poor cells. I use 3 of them in series in my transmitter, 3 X 4 cells in series for the starter or control panel. The big advantage is that you can charge them anytime, they have no memories and great capacity.