help with more speed

[audipiglet]

Hi all, I have bought a electric bike kit off ebay,

http://www.ebay.co.uk/itm/170776899992?redirect=mobile

I'm happy with it, its good for a cheap motor and I am running 36v 20ah sla batteries and I'm getting a top speed of 23mph on a flat with out peddling and a range of at least 13 miles, (the distance to my work) and was wondering if I could bump up the top speed a bit, when I need to replace the batteries I was going to get a 48v one but till then is there anything I can do to the controller? If a picture of inside the controller would help I can take the cover off, also a bit of a noob so please be gentle with me! Here are some pictures of my bike

 

[motomech]

Well known kit and associated complain here.
The short answer is, get rid of the "ball and chain" of those primitive SLA's, and go with 48 Volts of modern chemistry and you won't look back.
You had better get a rear-view mirror to look back then, because you will be doing 26 to 28 mph.

When will these vendors STOP offering these boat anchor batteries?
They are just doing a major dis-service to their customers.
In a way, it's the old "bait and switch'.

 

[audipiglet]

That was going to be the next battery I got, a 48v lithium battery, I'm sure the slas's are holding me back but I will stick with them until they die now that I have them, I was just wondering if there was anything I could do until I get a better and bigger battery.

 

[Drunkskunk]

22 to 23mph is about right for top speed out of that motor on 36volts. So there isn't likely anything to be gained in the controller. You might get more torque out of it with a shunt mod, but that would also very likely hurt the batteries quickly.

Basicly, you're at about peak performance with those batteries.

 

[audipiglet]

Cool, thanks everyone 48v for my next battery then!

 

[Hillhater]

That was going to be the next battery I got, a 48v lithium battery, I'm sure the slas's are holding me back but I will stick with them until they die now that I have them, I was just wondering if there was anything I could do until I get a better and bigger battery.

you could try a bigger front chain wheel ....and then pedal faster !! :wink:

Oh, and dont be surprised if you need a new controller too, when you change to 48 v ! :?

 

[Samd]

More volts = more top speed. So increasing volts to say 48v will get you cruising at higher speed as pointed out.

Many controllers fry at ~50v, you could take less risk when moving to lithium - 10s lipo would be about 37 to 42 volts.

But also, foing to lipo means you can supply more current on demand from the controller. Current = torque = much better acceleration. And by dropping a few kilos from using lipo, you acceleration will benefit even moreso.

I'd get those batteries down lower on the bike regardless. That thing must handle like a greasy pig in traffic....

 

[d8veh]

Nothing you can do to increase the speed other than getting more volts. Your controller will almost certainly work with 12S lipos, which are nominally 44v but spend most of their time around 48v, which will give a 33% increase in speed. A 48v battery fully charged will be close to 60v, which might smoke your controller, so if you want to go about 50% faster, that'll do it but it would be best to get a 48v controller at the same time. Make sure you get some good mirrors because once you go over about 23mph you'll be noticed by our friends in blue, and it's a huge dive if you get your collar felt - no insurance, no MOT, no licence(?). etc, etc. Suddendly 23mph sounds a lot better. I'm guessing that your in UK as you mentioned UK Ebay

 

[dogman dan]

A 48v lifepo4 battery will not likely smoke that controller. They almost always stand up to 63v actual voltage.

Get a 48v 15 ah pingbattery for your next battery, and you'll have about 27mph for twenty miles. 30-35 miles possible slower.

Get it as soon as you can possibly afford it, you won't be sorry. More for the range and lighter weight than for the speed.

If you want really fast speeds, then a 72v controller and high discharge rate batteries are needed.

 

[wesnewell]

That was going to be the next battery I got, a 48v lithium battery, I'm sure the slas's are holding me back but I will stick with them until they die now that I have them, I was just wondering if there was anything I could do until I get a better and bigger battery.

You could always just put more voltage in series with what you have now. Check the big caps inside your controller. If they're 50v caps you could add another 6v battery in series for 42V system. If they're 63v caps or higher, you could add voltage accordingly. FWI, most 48v lithium battery packs charge to about 60v.
If you're thinking about using lipo, then you could remove one of your 12v sla batteries and replace it with a 10ah of 6s lipo, among lots of other ways.

 

[audipiglet]

Cheers guys, I have lots to think about now, yes I am in England, Norfolk, I will be using it on the smaller back roads where I don't see any cars all the way to work, its not too bad at the minute having the batteries high up but this is only my first go at building a electric bike, just trying things out and seeing what works and what doesn't, now you have said about no insurance, tax, 23mph doesn't sound too bad but I would like 23 all the time not just on the flats, so the ping battery sounds good, I'll have a look now and see where the best place to get it from here is and in much I need to save and ebay the sla's

 

[audipiglet]

I have took the lid off the controller and the big caps are rated at 63V so if I got a 48v LiFePo4 battery it would be around 57.6V off the charger (16 x 3.6V) and would not fry anything and LiFePo4 sounds a little more noob friendly than lipo, does all this sound right?

All the big caps are 63V and the little ones are 50V

 

[dogman dan]

Yup. That looks good to go for a 48v 15 ah lifepo4 battery. You won't regret it, provided you buy a big enough one, from a dealer that sells good stuff.

My recomended vendor is Pingbattery, or Emissions Free. With Ping, you need 15 ah, because your controller will put out 22 amps continuous. A 10 ah size ping would only be good for 20 amps continuous without risk of damage. So get a 15 ah ping. Mine works great with a very similar motor and controller.


Or go to Emissions Free, where he sells A123 lifepo4. A123 has a much better discharge rate, so a smaller pack from Cellman will be more than adequate.

Either one should be able to fit into the triangle of your bike frame. Once you lose that lead chunk on your rear rack, your bike will handle 100% better. But if you must, squeeze a summer out of your lead. If possible, build a way to carry some of that lead in the triangle now. Just relocating it will help a lot with the handling.

 

[knoxie]

Just slot in another battery and give it a go for sure you need to get those SLA batts off the bike in the near future but if you want a bit of a speed boost then add another battery, I know how heavy they are though as I used to use 12AH ones so 20AH ones must feel like you have a small child riding on the back of the bike, might be an idea to check the maximum loading on the rack first.

Check the Fets in that controller to see what their maximum voltage rating is, bearing in mind they will most likely be copies

I find 25-27 mph on the flat is easy fast enough, any quicker and you really do stand out, I have been riding ebikes for 10 years here in the UK now so have a lot of experience, I have never had any problems from the po po and in fact the only time I was stopped they didnt even notice the motor :lol: it was sticking out like a sore thumb.

Drop another battery in there and give it a go, of course I wont be held responsible if it smokes when you do come to upgrade I would skip the ping battery and go with 20AH worth of lipo and get them mounted inside the frame. Speak to jozzer at jozztek in the UK as he can supply you with the batts and is very helpful.

Nice bike by the way, glad you are commuting on it as well, thats one less gas guzzler on the road

 

[dogman dan]

Yeah, one option is to buy one 3s lipo and a 50w charger fairly cheap, and try out 48v right now. I wouldn't buy more lead though.

You could buy a 6s lipo now, and drop one lead battery now, if you have money. Two 6s lipos, and you could make a 5 ah range extender. Run the lead awhile, then unplug it and plug into 44v lipo when you get to that big hill.

But the lipo lovers always forget that a pingbattery should last 4 or more years. Potentially much cheaper per mile with the ping or other lifepo4. Don't get me wrong, if you had a 40 amp controller I'd be pointing you straight for the lipo, or at least higher discharge rate lifepo4.

For a 20 amp commuter, a pingbattery works beautifully for years. I got 3.5 years from my first one, and so far 2 years from my second one. 5 ah of Lipo is cheaper if you need a 5 mile range, but the 15 ah ping makes the bike into a legitimate car replacement, with 20 mile range at full speed, and 30 miles at slower speed. Enough for real travel.

 

[audipiglet]

How did you know the controller was 22 amps? And what are the fets in the controller? Thanks knoxie I'm happy with my bike, I have done over 120 miles in the last week of sunshine here and loving every minute of it! I am getting rid of one of our cars now my bike is working so I am saving £6.30 a day so won't be too long before I can afford a new battery, if I upgrade the controller to a 40 amp controller will the motor be able to cope? If so I will get a 14s lipo (58.8V off the charger) and a new 40 amp controller, if not I will get a 48v 15ah pingbattery.

 

[dogman dan]

Well, 90% sure it's just like all the other kit controllers out there, based on the speed you get at 36v. Extremely unlikely it's more than 22 amps. Typicaly it's a "20 amp" controller in these kits, and most of us with a wattmeter actually see 22 amps with em.

But it's possible you have a bigger controller. Not likely in a bargain priced kit though, because that would cost the vendor profits. If you buy a bigger controller, then pingbattery would not be recomended. 40 amps can melt the motor, but it's not likely that it will if you keep the rides under 10 miles.

Just upping the voltage to 48v would get you into speeds where you need better brakes, tires have to be in good shape, and no more pedaling unless you modify the gears for faster traveling. More amps just gets you to your top speed faster, or if going up a hill, up the hill faster.

 

[Drunkskunk]

its a 36 volt, 800 watt controller. 800w /36v = 22.2A. But it also helps to know that 22 amps is the standard setting for those Inferon controllers. Its the same controller as they offer for the 48V, 1000watt motors, only with a different LVC programmed in.

The FETs are the MOSFETs, the black squares with the 3 legs one one end, and the metal tab at the other with a screw in it. you have 12 of them. They controll when and where the power flows.

If you're brave enough for Lipo, you can go for 15s, which is 63V right off the charger. Still in spec. But I'd recomend LiFePO4 for a comuter bike. Lipo is relitivly short lived, and more like racing fuel for Ebikes.

 

[audipiglet]

Thanks everybody, it's sorted then, 48v 15ah ping battery it is for me! Shouldn't be too long to wait only a few weeks, I have learnt so much in the last few weeks about every different part of a electric bike and I couldn't of done it without you lot, thank you for helping all the noobs like me!

 

[wesnewell]

Controller watts are rated like motor watts. That's a continuous operation rating, so don't assume an 800W controller will only put out 800w of power. If you want to know what they will put out, you have to know how many amps it's set for. My 48v 500W controller was set to 30A, so running 60v it will put out 1800W, and after I modded the shunt to 42A, it put out more than 2400W. Likewise, my 72V 40A 1500W controller will put out ~4000W using a 100V battery pack. On level ground, the output will drop considerably once top speed is reached. Hopefully to a level that won't burn up the controller or motor.

 

[dogman dan]

Yeah, I sometimes think they just put any number they want on the stickers. But a great many kits do come with the same 20 amp controllers that actually put out 22 amps continuous. The same 20 amp controllers can put out a very breif spike of about 30 amps, that will show as max amps on a CA. But load them down on a nice steep hill, like above 10% grade, and you'll see continous 22 amps on the display as the max.

I learned all this in the real world, back when a few different vendors were sending me kits for extensive testing and reviews.

But it's changing all the time. The yes branded kits Wes has been using and recomending do come with more powerful controllers and motors in some models. But mostly, you see that 22 amp infinion clone because it's cost effective to the vendors.