controller rating

[richdeloup]

A quick question from a beginner, it has prob been covered before but cant seem to find the info needed.
Im after a new controller and they seem to range hugely in price from £25-£250 with different amp and wattage ratings.
Could someone please tell me if it is worth paying more and if the expensive ones (2000w compared to 300w) really make a difference?
(Motor rated at 1000w 48v ping)
thanks in advance. Rich

 

[dogman dan]

Assuming your battery is a 15 ah pingbattery, I'd advise looking for controllers that specify 20-25 amps. Others report running 35 amp controllers, but I recomend more headroom to go easy on the battery.

So about 1000w max, not 2000 unless you get a stronger battery.

 

[Jeremy Harris]

First off, the "wattage" ratings of many controllers are fairly meaningless, and serve more to confuse than help, in my view. Controllers have two limits, a maximum current limit, usually either programmable or at least able to be adjusted by some fairly crude hacking, and a voltage limit, determined by the safe maximum working voltage of the internal components.

In your case, you are limited to a modest maximum current by the maximum that your battery can safely deliver; I'd suggest no more than 1.5 to 2 times the capacity of your battery for a Ping pack (so 15 to 20 A max for a 10 Ah battery, 30 to 40 A max for a 20 Ah batttery).

A 48 V Ping battery will be around 58 to 59 V when hot off charge, but pretty much all 48 V controllers will deal with this OK. Next look at the current limit for the controller, and if the information is available, the type of FETs used. The current limit needs to be no more than around 1.5 to 2 times your battery capacity in Ah, as already mentioned. If you get the chance to get a controller with low on resistance FETs (the best in this voltage range being IRFB3077s) then go for it, as it will run cooler at high current), but at this power level even the budget controllers will probably perform OK.

Next, think about what you might want in future. If you want an upgrade path, then a programmable controller, which pretty much means a Xiechang (labelled/sold as e-crazyman, Keywin, Lyen, "Infineon" and probably a few other names), as these can have a lot of settings changed using a free bit of software on a PC. If you just want something to work and aren't bothered about changing settings, then the Greentime controllers seem hard to beat in terms of value at the moment.

 

[NeilP]

(Motor rated at 1000w 48v ping)

To expand on Jeremy's answer, a motor can (to a certain degree) take what ever you throw at it, for a period.
What I mean is that the motor is not the limiting factor in the power rating of your system. You could feed 5000Watt in to a 1000Watt motor (though not advised) and it would take that power, run and deliver those 5000Watts....until it over-heated.

So to really know what your motor will take with relation to power we need to know what it is..or even a picture of it so we can see what it is like ...and maybe give you an idea of what we really think it can take as opposed to what the manufacturer or supplier says it can take.

 

[Jeremy Harris]

(Motor rated at 1000w 48v ping)

To expand on Jeremy's answer, a motor can..to a certain degree take what ever you throw at it for a period.
What I mean is that a motor is not the limiting factor in the power rating of your system. Would could ( though not advised) through 5000Watt in to a 1000Watt motor and it would run and deliver those 5000Watts....until it over-heated

So to really know what your motor will take with relation to power we need to know what it is..or even a picture of it so we can see what it is like ...and maybe give you an idea of what we really think it can take as opposed to what the manufacturer or supplier says it can take.

Very true. Motors will just take whatever current is available when loaded, pretty much until they burn out unless the current is limited in some way (usually by the controller). They also don't care too much about voltage, as this only determines the rpm they run at (more volts = higher rpm).

In this case the battery pack is probably the limiting factor though, as the Ping packs, very good as they are, aren't comfortable with a discharge rate above about 1.5 to 2 times the capacity.

 

[richdeloup]

Thanks for all the answers, very informative once i get my head around it all!
My motor is this cheapy Chinese one but im already looking at upgrading unless you think it could be run at a higher rating?
http://wholewide.en.alibaba.com/productshowimg/495829893-212023422/48V_1000W_e_bike_motor_kit.html

Jeremy, can you recommend any good UK suppliers to buy an 'off road' kit from 40mph+ as im not sure the Chinese kits are up to what i want? Im in Wimborne so not a million miles from you!

 

[Jeremy Harris]

Pretty much all ebike stuff comes from China, although some retailers may pretend it doesn't. Quality and performance is pretty variable, but generally quite a bit of the Chinese made stuff is OK. There are very few UK dealers, and most I've seen have charged a massive markup on the cost of the parts from China.

Good suppliers I know of (all outside the UK I'm afraid) are ebikes.ca (in Canada), Paul (Cellman) in China (but he's English), Keywn Ge (E-crazyman on ebay), in China, Ed Lyen in the US (who sells hand-built Xiechang programmable controllers via the sales bit of this forum).

The chances are that motor will be all right, and may run as well as you need for now with the battery you've got. I'd suggest getting a 12 FET Xiechang controller, either from Keywin (see here: http://www.ebay.com/itm/48V-600W-brushless-controller-for-E-bike-scooter-/300352534034?pt=LH_DefaultDomain_0&hash=item45ee67f612 or perhaps this one: http://www.ebay.com/itm/72V-1500W-brushless-controller-for-E-bike-scooter-/300705286217?pt=LH_DefaultDomain_0&hash=item46036e8849) or perhaps from Ed Lyen (see here: http://endless-sphere.com/forums/viewtopic.php?f=31&t=17683). These can be tweaked/programmed to deliver more power than your battery will be comfortable with, and, at least for the basic e-crazyman version, offer good value.

 

[d8veh]

The Chinese stuff should work really well for what you want because most of the stuff is Chinese anyway regardless of where you buy it from.
The only UK supplier that I know that does what you want is Frank at http://www.xipi.co.uk. His kits are pretty well sorted, but relatively expensive compared with doing it yourself with stuff from China.
Regarding, the controller: you're right that there's a lot of different ones and they have different features (like cruise, speed limit, self-learning the motor configuration, etc) as well as power and voltage ratings, so first you have to decide what you want to do. Many don't have pedal sensor inputs, although you can get round that by using a Speedict. While I think about it, look out for the imminent release of the new programmable Speedict Controller that will have the built in bike/battery computer with Android interface and other promising features.

 

[elmannen]

Maybee this kit? i have this myself and have done 2500 km so far on it.
Time will tell how the quality is.
/Lasse
http://www.ev-power.eu/EVBike-Kits-1-1/E-bike-conversion-kit-EVBike-36V-500W-Rear.html

EDIT: oppss, it was only a controller you was looking for.

 

[Punx0r]

I don't think anyone in the UK sells a 40mph kit. That would require ~2000W, so it's a DIY only proposition, I think.

 

[Jeremy Harris]

I agree with Punx0r, 40 mph is pretty much into serious DIY build and modify territory. Also, I doubt your Ping battery is going to like the discharge rate you'll need to get to 40 mph, a couple of kW is around 40 A, more than most Ping packs would be comfortable with.

If you want that sort of performance, then you're going to need batteries that are happier with higher discharge rates. The choice would really be between RC type LiCO2 LiPo cells and decent (perhaps A123) LiFePO4 cells, and almost certainly means a home made battery pack. Also, that sort of speed will need a higher voltage, as even the fastest wind hub motors aren't going to get you to 40 mph on 48 V nominal.

I'd suggest taking a look at Justin's simulator: http://ebikes.ca/simulator/ and seeing what sort of performance you're likely to get for different battery/controller/motor combinations. It should give you a fair insight into how different combinations might work. I've just done a quick look-see, using a 48 V (52 V in reality) 20 Ah Ping battery pack and even with the fastest wind motor I could quickly find I could only get a max speed (with 26" wheels) of around 34 mph, with the old Crystalyte 5302 motor, with the simulator showing around 1400 W at that speed (no wind, no gradient, light weight rider and bike). I don't think that there are many motors with winds as fast as this available now, but may be wrong.

 

[richdeloup]

A great help, thanks to all, should have asked sooner as been scratching my head for 6 months.

 

[richdeloup]

Hi, Jeremy, do you know of anyone in the UK who could build me a battery pack using the cells recommended or is it a pretty simple project to connect them up? Does anyone offer a DIY casing which cells can just be slotted into to suit requirements or is this way off track?
Is there a UK equivalent of Hobby King for cells etc?

 

[wesnewell]

Just to answer your question about the controller. The watt rating is the max 24/7 operation rating and has nothing to do with how many amps/watts it will put out. My 72V 40A 1500W controller cost $35 shipped. Run on 100V pack it will put out ~4000W. I have a 48V 1000W motor. Both still going strong for over a year and >5000 miles.

 

[Jeremy Harris]

Hi, Jeremy, do you know of anyone in the UK who could build me a battery pack using the cells recommended or is it a pretty simple project to connect them up? Does anyone offer a DIY casing which cells can just be slotted into to suit requirements or is this way off track?
Is there a UK equivalent of Hobby King for cells etc?

There may be one or two on here from the UK that might be able to help, but other than that it's really down to just a handful of people reselling imported products, sometimes with a variable level of knowledge about the actual product itself.

Building packs isn't hard, really just a matter of understanding some of the risks and treating them with respect. There are quite a few threads on here showing the way people have built packs themselves. For high performance, then there is little to beat using RC-type LiPo packs, and HK off the best value by far (you'll pay maybe twice as much for UK sourced packs). There's at least one member here who makes and sells wiring kits to join RC packs together (http://endless-sphere.com/forums/viewtopic.php?f=31&t=30367 ) or you can make your own up (there are some good instructions in that thread).

In addition, you'd need a charger, and this is one area that gets a bit messy with RC-type LiPo packs, a you inevitably need to take the pack partially apart in order to connect the charger and balance leads. Again, there is some good information in that thread about leads that should help.

You'll find that it's often a lot cheaper and easier to buy stuff from overseas, rather than try and find a reliable UK seller. Sad, but it seems the UK market just isn't big enough to attract competition to bring prices down.

 

[richdeloup]

Ok, looks like im going to give battery pack building a go, stand back everyone!
Can someone point me to a preferred HK cell that is used as ive taken a look at their site but could do with some advice re C ratings etc before placing an order.
Will prob try to build a 100v pack, not too bothered about distance but does the Ah rating also effect performance/capabilities?

Once again thanks for the replies, ill prob be off to the battery threads researching the technical parts.

 

[Jeremy Harris]

Either Zippy or Turnigy packs will do, you don't really need more than the 20C ones for an ebike (20C being the maximum discharge rate, the multiple of the capacity that the cell can deliver, in A). The reason is that if you discharged at 20C then you'd be running the pack flat in just 3 minutes, the max an ebike is likely to need is around 5 to 10C.

100V is enough to kill you from electric shock if you get something wrong, so if you're not familiar with electrical safety then take care and double check everything. These batteries can store and very quickly release a fair bit of energy and if something goes wrong it can be pretty spectacular. You might want to start out building a lower voltage pack (below about 75V there's little chance of serious electric shock) until you've gained some experience, then add to the pack if you feel you need a higher motor rpm.

 

[richdeloup]

Wesnewell, thanks for the info, i may try to copy your set up if thats ok! thats pretty much the performance that im after.
Do you know where i could buy the same controller from as ive done various searches and links that are out of date to no avail.

Update- OK found a supplier. Thanks for the tip!

 

[Jeremy Harris]

When buying a controller consider carefully if you may want to change the settings in the future. Although most controllers are programmable, we only have open access to the programming port on the Xiechang controllers (e-crazyman/Keywin, "infineon", Lyen and a few other names for the same controller). There are cheaper controllers available, like the Wuxi ones (Greentime, Hua Tong, KU series) but the programming port is non-accessible to us at the moment, meaning that only very crude adjustments of low voltage cut-off and gross current limiting behaviour can be changed, and even then only by soldering stuff inside the controller.

My personal view (and I know others may disagree) is that being able to adjust the controller's settings quickly and easily via the programming port is pretty useful, and worth paying a premium for. The 1500W controller I linked to previously, (http://www.ebay.com/itm/72V-1500W-brushless-controller-for-E-bike-scooter-/300705286217?pt=LH_DefaultDomain_0&hash=item46036e8849) although considerably more expensive than the one that wesnewell mentioned, is programmable and can fairly readily be re-programmed using a serial lead from a PC.

 

[richdeloup]

Thanks Jeremy, ill look into the programmable controllers as i can see it being useful.