Schwinn S-350 upgrades

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scooterNoob13
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Schwinn S-350 upgrades

Hey everyone, I'm new here and was looking to soak up some knowledge. I just picked up a used stock S-350, and was wondering if anyone could give me their insight on the best method to give me a little boost in both speed and range. Running a 350 Watt/24V motor, 2 x 12V 10AH SLA batts in series. I was thinking of stepping up to a 500W motor, should I also step up the system to 36 or 48 V with higher AH ratings? I realize I will need (or should get) a 36 or 48V controller, but would I also need to rewire the system with a lower gauge wire for the increased amperage? I also want some thoughts on the band brake configuration that comes stock with the S-350, I thought about maybe replacing it with a caliper and rotor-type setup. Thanks everyone for your time.

scooterNoob13
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Re: Schwinn S-350 upgrades

Alright ppl, I been lurkin around on my own tryin to figure out some cost efficient ways to boost my Schwinn S-350's performance a bit. I have performed a simple shunt mod, adding a solder bridge across about half of my controller's shunt. This seems to give me much more hill-climbing ability, but not much in the speed boost department. I'm considering wiring the so-called "turbo" button, using a pushbutton switch to activate a high-current relay to power the motor with the battery directly, bypassing the controller. I just need a little more information, such as what current rating should I be looking for on my relay, with my 24V/10AH 350W setup? In other words, what is the MAX current my 350W/24V motor will draw, it's rated current is 22A, but I'm sure it will draw more than that. Is it as simple as the max voltage divided by the motor resistance (~27V/.3Ohms=90A) ?? Should I just put my own shunt in series with the relay to limit the current to some max level, or will that counteract the effectiveness of the bypass? Also, should I simply be able to physically 'jump' across the controller with the relay and rely on the ground to be supplied back through the controller? Thanks if anybody is out there.

e-doggies
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Re: Schwinn S-350 upgrades

To get more speed, you will need to add a third 10Ah battery and try to run your existing 24V controller at 36V. If your controller will not accept the higher voltage, you could still buy a good 36V replacement that would have better response than the stock Currie controller. A high-current relay will be hard to find and probably not cheaper than a new controller. Even with a relay, your top speed should not be much greater unless you add more voltage.

I'm not sure what the peak amps are that your stock motor will draw. There will be a big inrush when the relay is first closed, of course. (0.3 Ohms of resistance in your motor seems low to me)

If you overvolt to 36V, your motor should be able to handle it unless you consistently run uphill at full throttle with a heavy load on a hot day.

It's my understanding that the controller regulates the negative wire to the motor. So, if that is true with your controller, and you use a SPST relay, it would need to be in the negative lead, and you would continue to pick-up positive to the motor from the controller output.

Hope some of this helps.

Dauntless
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Re: Schwinn S-350 upgrades

First of all, the new 650w Currietech might cost you something like what these parts will cost, and it's bigger, more stable, better stopping, etc. I'm 200 pounds and live in a hilly neighborhood, and mine ALMOST held up, but I let it go. (There's a 750w and a 1,000w now.) Absolutely no buyer for my old 350w, I think you'd need to weigh 120 pounds or less to ride that thing.

Which means it's a suitable candidate for experimentation. But will the motor hold up under the additional voltage? If you want more speed, you want to work with the gear ratio. I'd have to go count the teeth on the pinion, but if it's 11 teeth as the current bikes are and you increase it to 13, you go faster at the top end, at the loss of a little throttle response. That's going to cost you some of the hillclimbing capability, but if the shunt worked so well, you might be able to afford it. Assuming you can get a pinion that fits, you'll probably need a single, solidary link added to the chain, although maybe mot.

Now, I notice that they only seem to offer the 11 tooth pinion on the site, and there appears to be a 55 tooth and a 90 tooth for the wheel. If yours is 90 and you reduce to 55, ($19.35 plus shipping) you take a lot of links out of the chain and nearly double the speed from 12mph to about 20, but it's not having an easy time getting up there while it's stock. Your mod might accomodate this, but it also endangers your climbing. I'd prefer less of a change in the ratio, but that seems to be all there is. http://www.curriestore.com/1928-ezip-sprocket-rear-wheel.html

Back when I used to ride it I had a pair of riding mower batteries on the footboard, and some pegs for my feet. Dang, might have been good for close to 100 miles and I think it was $50 total, (Put several thousand miles on it) but it was too slow to ride far. For not more more than all those parts to upgrade, I also got a bigger more comfortable bike in the 650w, with better brakes and more suited to the speed. You don't want just one battery to go 36v, you need to replace all three because they destroy each other when they're mismatched. A controller, a charger, this just adds up.

Tell me how to do this shunt and I might take it up with mine.

WHo dares, WINS!!!!

scooterNoob13
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Re: Schwinn S-350 upgrades

Ok, so I've done a little more research, and this is what I have come up with. For now, I plan on sticking to the stock 24V system, mainly because I've heard that adding a new battery to a pack that is not new can be harmful to both the new and old batts, and also beacause I can't yet afford to invest $300+ for the Ping 36V/20AH LiFePo pack, which I would still greatly prefer over buying 3 new SLAs. So I'm thinking, for now, I should go one of two routes. Either I get the 600W Currie upgrade kit from superkids.com, which runs ast 24V and comes with a 40 amp controller, or... I pay a little more and get a 400W Kollmorgen brushless and a new 5k pot throttle. The 600W upgrage "should" give me more bang for my buck (and when I say bang, I mostly mean power) and I could use my old throttle, but I'm quite intrigued by the good things I've heard about the "Hi-Kol" brushless, such as better efficiency, low maintenance, and less noise. I've also heard these Kollmorgen's will handle 36V no problem, if I ever upgrade. A couple of questions I need answered, I'm a bit confused on this brushless motor, I've found many rated at 400W, some at 300W, and even one at 350W, but I've heard that they are actually the same motor, and they DO look identical. One guy said it's just the distributors rating them at different levels. Is this true? If so, this will probably be my choice, as I found a 24V "350W" brushless motor on monsterscooterparts.com that I'm sure is a Kollmorgen for only $75. With a $50 Magura 5k twist throttle, this beats the 600W kit by about $10. Let me know what you think. Thanks everyone

Forgot one other thing, like I said the 600W Currie upgrade comes with a 40 amp controller, but the Hi-Kol has only a 30A internal contoller, which I'm convinced would be a real pain to open up and modify or replace with an external. Also, the conventional "turbo" button wouldn't work with the brushless, as it's AC. So, with this in mind, do I get the 600W upgrade limiting at 40 stock, but more easily upgradeable (I have already done one shunt mod) ... or go brushless, knowing that upping the voltage (probably to 36V) will probably be the most that I can do for now as far as a quick mod. I do like the fact the Hi-Kol has a mostly sealed case, as I have been planning on doing some water-resistance modifications to the scoot, like sealing off the batt case, the motor, and maybe adding extra insulation on the wiring. As you may be able to tell, I'm quite torn here, please someone tell me that this Hi-Kol is worth the extra money I will probably end up spending. I know these wattage ratings are just that, ratings, and either motor could probably draw much more, so is this 600W going to give me THAT much more power, where I don't mind sacrificing the efficiency and quiet operation of the brushless, not to mention it's other advantages. Thanks you guys are awesome for answering with whatever knowledge you can provide.

scooterNoob13
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Re: Schwinn S-350 upgrades

Thanks for replying! I checked out a new Currie 650 and buying the whole bike ($300+) is a little out of my current price range. But as I said in my previous post, I'm considering the 650W Currie upgrade kit with 40A controller ($119). I'm really starting to lean towards the Hi-Kol though, Scott over at EVdeals can give me the motor, with a roller clutch and 15t pinion pre-installed for $169. With either motor I will be changing the old 11t sprocket in for a 15t, giving me a tiny bit more top speed (maybe not even noticeable) and I think the motor upgrade will make up for any acceleration loss from the gear change.

As far as the shunt mod, its actually quite simple if you have any electronics expeience. You will first need to open up your controller and find the shunt resistor, it will probably look similar to this:
shunt.jpg

Mine actually only has one, as this pic has two, but in either case if your contoller is potted (circuitry encased in rubbery material) you will need to locate the shunt and carefully use an exactoknife to cut away the material down to where the shunt is. (Carefull not to scratch any paths on the board) Once this is done you can do one of two things, either take a peice of coat hanger or other conductive material and solder it in parallel with your shunt. Or you can simply add a bit of solder to the shunt itself, effectively creating another path for current. Either one will reduce the overall shunt resistance by a bit, tricking your controller into putting out more current. If you use the coat hanger, you may want to figure out your original shunt resistance and the resistance of the hanger peice do a few calculations, giving you the ability to more finely tune the mod. I just added a glob of solder to one leg of the shunt, and I noticed a difference. Here's an example pic (again not mine, just one I found, but looks similar, but mine had potting)

I hope this helps!

Dauntless
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Re: Schwinn S-350 upgrades

That website is THEsuperkids.com, for others who want to look at it.

Is there any reason the present controller wouldn't run that brushless motor? Seems like the way to go, with the thumb throttle it says it requires. (Anyone know why it would?)

But without spending the $119 or more, I see the possibility that if you put that 3rd battery in there, you'll be almost up with that 650 watt upgrade, and I know I can get one of those batteries for $20. As we've both mentioned, one new and two old puts all three at risk, but. . . .

Of course I hate to sound knowing on this part, that's what I'm trying learn here, such as with this shunt mod. If all that and three batteries gets mine running like 500+, I might be able to ride it again.

WHo dares, WINS!!!!

scooterNoob13
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Re: Schwinn S-350 upgrades

My apologies, I did forget the THE. The 400W Kollmorgen brushless is eqquipped with an internal ~30A controller, meaning that if I wanted to run the motor with an external controller (such as my present one) I would have to open up the motor and basically remove the internal one. Not something I'd really be looking forward to (If you've ever seen fully potted electronics, you know what I mean). I have thought about it, as my controller would probably run the motor fine if I took that route, but if I were to open it up, I might just as well modify the Kollmorgen's internal contoller to give me something around 40A. It is my understanding the Kollmorgen requires a 5k potentiometer throttle because it is an AC motor, and the voltage or current to the motor is regulated in a different way than that of a DC (brushed) motor.

Dauntless
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Re: Schwinn S-350 upgrades

So if it comes complete, then jump on it.

Meanwhile, there's the pic of my controller. I take special note of there being a difference between "LL" "LH" and "HL," though I don't know what it really means. But it's not like your pic. At the bottom base of the hoop there's what looks like a braided copper surface. I'd at a loss on how to proceed.

WHo dares, WINS!!!!

scooterNoob13
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Re: Schwinn S-350 upgrades

If I were to guess (and that's what I'm doing) the "L L, L H, and H L" would indicate that a logic LOW(0V or ground) applied to both the SEL1 and SEL0 terminals (or whatever) would effectively limit your controllers current output to 22A, subsequently applying a LOW to the SEL1 and a HIGH(+5V I'm assuming from the indications on the board) to the SEL0 would limit the output to 30A, and so on. It would be up to you to find out for sure where these SEL1 and SEL0 terminals are or where you should jumper to. I see them indicated again on the bottom right side of the pic, underneath VDD(which is referring to the 5V control voltage), but I can't see what's underneath the quality control sticker. Anyways, if you were able to increase the current in this way, I would see no need for a shunt mod unless you want to exceed the 40A limit. If so, adding a bit of solder to the hoop should work just fine, but if your controller is labeled as a 30A controller, exceeding 40A may not be a good idea.

Dauntless
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Re: Schwinn S-350 upgrades

That's not a "Quality Control" sticker, it's a "Quite Chinese" sticker. Demonstrated by the fact it sort of sticks but it moves around and ends up covering things. Underneath is SEL1 then SEL0.

Hey, I'd love to know where to take a class to learn to interpret this stuff, but I'm thinking I'm understanding that pathing is saying that it is currently 40A. The replacement part controller is 40A, same as their bigger 24V scooters. But it is labeled as 30A. Abd it says 18 volt cutoff/7-26 volt operation voltage.

Are you literally saying to just layer some solder on the entire hoop to increase the guage? Coupled with a 36V battery setup? HOW MUCH solder?

I got this to carry in my car when I was freelancing around LA where the parking is difficult so I could ride up from 2 miles away, etc. Wasn't all that much faster than walking. Within a few days of getting it I needed to cover 11 miles on it to recover a car without a ready bus route over the weekend, and it got me there in half the time I could have walked. My neighborhood is hilly, I'm 200 pounds, and this is 350w. Meaning overall it really wasn't good enough for me.

Since I don't have anyone else around who wants to ride it, and I can't sell such a dinky thing, I'm content to risk destroying it. But I don't want to sacrafice it carelessly, if I'm going to brick it I just want to make an honest effort.

WHo dares, WINS!!!!

scooterNoob13
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Re: Schwinn S-350 upgrades

Yeah I'm actually going for an applied science degree in computer engineering at ITT Tech. I've learned quite abit there but I would say I've still learned more doing reasearch and experimenting on my own (cautiously).

Yes, you just need to add solder to the hoop itself, I would recommend covering like a quarter or half way up one leg to start out with. I've heard of people making a complete bridge (covering the whole thing) and it works fine, but I would start with less and see how it reacts. Check your motor after running it with the mod to see if it's getting hot or anything.

I'm just under 200lbs and I live in a small community and my little 350 it perfect for getting me around to work and to the store and other places where I don't have to climb too much. There are a few nice hills around, however, so I would like to get the scoot accelerating up the inclines and topping out at like 20-22, which is the main reason for the mods that I plan on doing.

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