10 year old lead acid 36V e-bike needing an upgrade!

[monkeychops]

Got this reply from tncscooters:

**********************************************************
The T3630 controller can not be run at 48 volts. This would burn up the controller. The internal capacitors are not designed to work with the higher powers you will see at 48 volts.

We do not suggest you use the 36 volt version of this controller on a 48 volt system. The low voltage cutoff is
set to a higher value so that you don't over discharge your batteries when riding.

The only controller we offer that does not have a low voltage cutoff is the ZY-KK70 controller. [$90]
This controller is capable of running from 24 volts to 60 volts.
**********************************************************

very disappointing

So, to summarise:
1. If I buy a 48V controller it will almost certainly have a (roughly) 41.5V LVC which is too high for SLA batteries.
2. If I buy a 36V controller it's likely to fry quite quickly.

After about an hour of looking, I found this post http://visforvoltage.org/forum/2973-building-own-emoped
About half way down a guy says that his YK40 (36V) controller works at 48V. Hardly scientific evidence but all I've got at the moment.

Can anybody help me find a controller?

[Samd]

Piffle. He is just trying to get you to buy the 90 dollar controller.

Your old controller was a bag of rats, don't assume a new one will blow up also.

You should read this thread from start to finish: http://endless-sphere.com/forums/viewto ... 28&t=18505
Several other controllers mentioned there.
The aprilia is a different bike but it summarises your problem precisely. Stripping all the old controls and using a new controller on a brushed dc motor.
Three people on that thread are using Yk controllers at 10s = 42 volts with no problem.
Perhaps it is time for you to get rid of those one tonne SLAs and buy some 33.6 volt LiPos to match a cheap controller.

I would buy a yk40 and a 9 dollar throttle to suit. Wire the bike from scratch.
Do away with guessing and get tinkering and wondering. We are here to help.

Sam.

[monkeychops]

Thanks Sam, I will make a start on that thread. Looks like quite a bit of useful reading.

In the meantime, I bought a 36v controller. So that's 2 on the way now.

I hear what you are saying about the LiPos. I spent some time thinking about that this evening and measuring and researching etc.

The trouble is:
1. my bike frame is built around the battery box and so it's a tricky job to work out how to fit the lipos in the space.
2. i'm slightly put off by the extra care you need to take of lipos.
3. i like the look of lifepos but they are expensive and I can't see any decent capacity ones that would fit into my existing battery box (approx 45x10x10cm)
I know this runs against what people usually advise here, but for someone who isn't that good electrically, the simplicity and ruggedness of SLAs is a real advantage.

I got so fed up failing to work out a solution that I started wondering if the simplest next upgrade path would be just to add yet another 12v SLA...

[Samd]

Generally, more volts equate to a faster engine top speed - therefore a higher top speed for the bike.
More amps mean more torque, so better acceleration.

So if you are going to have a fixed battery size in watt-hours, you may prefer to stop adding voltage to you battery if you were reasonably happy with the speed already.

You can add more amp hours by buying more batteries. And you can control amps with the current limit on your controller.

My bike tops out just under 60kph - enough for me. It accelerates ok, but I may go to a 40 amp limit on my controller soon to see if it is even better at the traffic lights.

Do you have lots of stops and starts where you live, or more straight lines to ride on?

I actually take a longer ride each day to and from work, an extra 600 meters. But I get there quicker because i only make on stop.

If you are looking at lipos the hobbyking site has good dimensions to size up packs for your battery box internals.

[monkeychops]

I probably won't add the extra 12v SLA, I'm not sure the motor would be that happy about it. Still in theory it would give me more range if I didn't use full throttle as much. I've come to realise that the effective Ah capacity of my SLAs is half the rated capacity, so 6Ah in effect, due to the 'Peukert' effect.

Thanks for the lipo tip. I think building my own lipo pack might be the only way I could re-use the existing SLA battery case. I just don't fancy the faff of balancing the batteries, keeping the charge levels topped up when the bike is not used for a while, needing to use a Cycle Analyst (or equivalent). I guess I could get used to it.

Most of my 15 mile commute is straight lines. Relatively few hills or stop/starts. Which is why a good top speed is particularly attractive. About 8 miles of the 15 are on fairly car-free roads.

In the meantime I'm going to try to chill out and wait for the 2 controllers to arrive. Surely one of them will work.

[Samd]

You're doing a great job of thinking it thru MC. I just balanced my packs for the first time in 8 weeks the other day - only a 0.02 volt difference across the cells! The turnigy lipos tend to be high quality. They only go out if you dicharge the pack. I tend to only use up to 75% of my pack so I dont eem to be going out of balance...

There is usually a certain voltage point where spark will arc between the brushes inside the motor, smell the ozone. Motors can usually take an extra 50 percent, beyond that is a guess. Some folks end up offsetting the rotor angle by up to ten degrees to stop it at higher voltages...

Take care

[monkeychops]

Update: 48V controller came through from the far east. It's way too big compared to the size on the eBay description page and it's clearly in used condition. I have sent a message to the seller.

For reference, this controller: http://www.ebay.co.uk/itm/400244692042. Seller id = virtualvillage-au1

In the meantime a 36V controller arrived from a UK supplier which seems ok.

The wires going to the motor shorted out last week and I have been trying to get the hub motor off (see other thread). Cone spanner has done it's job (just, nearly stripped the thread on a nut) but the cassette removal tool sold to me by the local bike shop is slightly too small (I actually took the wheel in too the shop too). Looking at the ones on eBay I think I need a Shimano one, as the 'ridges' are higher compared to the non Shimano ones.

Progress is slow... but at least the weather is cr&p so I don't feel I'm missing riding the bike so much.

[monkeychops]

Update: got the motor cover off finally. The hole on the Shimano cassette removal tool was too small so had to drill it bigger a bit (hard work). Re-soldered new wires on and tested with a 12V car battery charger. 'Just' need to fix everything back onto the bike properly now and wire in the new controller.

If it all works, phase 2 will be replace the SLAs with lipos and phase 3 replace the brushed motor and controller with a brushless 500W one from cellman (probably).

[Samd]

Sounds like you are having a bugger of a time!

[monkeychops]

yes I am, but mostly enjoying the challenge!

Update: new controller seems fine but haven't been able to test it on a real ride. I'm having torque plate/arm issues. Until a few days ago I hadn't appreciated that the axle wants to turn and needs to be fixed with an arm or plate. I had a torque plate but hadn't realised it's function. Then realised it is too worn to be of any use. Ordered a couple of chunky 10mm spanners to act as torque arms and getting to local car mechanic to attempt a repair on the torque plate.

In the meantime I am gradually accumulating more hand tools, power tools, connectors, wires, analysers etc. Plus a bit of knowledge too.

Slowly, slowly...

[monkeychops]

Update:

Finally got the torque plate fixed and added some wrench torque arms for extra safety. Wired in my power analyser and went for a test ride today. 6.5 miles, 2.3ah used, 18mph average speed, 20 mph max speed on the flat, peak power about 1000W, 20A. I was doing gentle pedalling, enough to keep warm. Everything held together and the replacement controller seemed to give more power up hills, but it was hard to be absolutely sure.

I was worried the new setup would use more battery juice, what with longer wires between the battery and the motor (going via a handlebar mounted power analyser), the controller possibly drawing more from the battery than the old controller, and also the temperature was quite low compared to previous rides at 9 degrees C.

Thinking forward to the next upgrade: 4 x 22v 5ah lipo batts to replace the 4 x 12v SLAs. From all I've read on the forum, lipo is the way to go. I will run with the current setup for a while though, to get confident with it, and to let myself appreciate each upgrade instead of trying to do everything at once.

[mxer]

Sound like your having the same fun as me UK sucks for bits i know Fantastic read tho, Got loads of questions awnsered here, cheers mate

[monkeychops]

Glad to help. Not a problem to feed back my experiences, given all the help I've had here.

I'm now wondering if anyone can recommend a not too expensive bulk charger for a pack I'm planning to build consisting of 4 x 6S lipos, 2 in series, 2 in parallel (if you see what I mean) giving a nominal voltage of 44V. I know lipos need balancing regularly but I'd also like the option of bulk charging all of them together without necessarily opening up my battery case.

Whenever I start trying to find something suitable I get bogged down (or side tracked). It seems like all bulk chargers need a 12V power source that is suitably powerful. But a lot of chargers seem to do so much and have so many features that I can't work out whether they would simply be able to bulk charge the pack I'm thinking of building. Any help appreciated. Maybe I should start a new thread for this one?

[Samd]

Gday again monkeychops.

I bulk charge daily and balance once every four to six weeks. If you don't use all the watthours of your packs they tend to stay closely balanced. I add an extra pack and find I only use about half as a result.

You will find lots of power supply options from PC's and regulated sources with different amperages, eg:
http://www.ebay.com.au/itm/HPS-680W-PC- ... 3a62f83be9
http://www.ebay.com.au/itm/AC-100-240V- ... 3cbc6cf2c8
http://www.hobbyking.com/hobbyking/stor ... upply.html

I use this bulk/balance charger, it's really good:
http://www.hobbyking.com/hobbyking/stor ... arger.html
some of the 6s chargers are ok I am sure, i just need 8s.

[monkeychops]

Update: bought 2x 4Ah 30C 6S Turnigy Lipos from HK. I will series them to get 44V. Obviously 4Ah isn't much capacity but I just want to try out Lipo without completely breaking the bank (maybe that will come later). Also bought an Imax B6 and power supply, and a series 4mm connector harness. The batteries are from the German warehouse and are on back order so I'm not expecting them to arrive any time soon.

I remembered recently that I had a spare battery case for my 3x12V SLAs, so I can put the lipos in there and keep my (modified with duct tape) frankenstein 48V SLA case going and directly compare them.

Also been in touch with cellman about his kit. Just slightly worried about the total axle length. His is 218mm and the axle on mine current setup is about 230mm so less space for torque arms and such.

[dogman]

Ouch. Just for the future, never ever order anything not in stock from HK. You might even try to get your order canceled, and buy something they have in stock, at the local warehouse.

[monkeychops]

Another ride of shame this afternoon while I was on a test ride. After about 5 miles of mostly full throttle riding the motor gave out. It seemed to slowly lose power over the course of about 10 seconds. After that, nothing. Zero throttle response. Got home and tested that the controller was providing power to the motor and it was so I think the controller is ok.

My gut feel is that the motor just couldn't handle the volts/amps going into it. It's rated at 250W (or possibly 200W) but on the 2 successful test rides I had done earlier (each about 6 miles) the power had peaked at 1000W and would typically be 500W on the flat under full throttle. In an earlier post above I think someone said the motor might eventually die - the stock setup of this bike was a 36V battery. I just thought the motor would last a bit longer.

Anyway, I've ordered a brushless 500W hub motor kit from cellman (the one that died is brushed), which will hopefully be happier with 48V going through it. In the meantime I will probably open up the motor and have a look inside, but I'm not all that hopeful I will be able to do much, especially given my limited knowledge and experience...

[Samd]

Hmm, you sure are learning a lot! Good job for sharing.

You'll need to swap the brushed controller for your brushless one you accidenatlly bought.

It is possible that you just wore your brushes out. These are easily made by hand from a lump of carbon and replaced. I have used spare brushes from a 20 dollar angle grinder in the past and shaped them by hand with a file. If they are small you can use the 'lead' from inside a large builder's pencil. Or buy a block of brush carbon off ebay for a dollar.

It might be that the motor got too hot and melted a wire, or the magnets got too hot and demagnetised. The ten second loss of power timeframe might indicate that insulation on a wire melted?

Throw up some pics and let's have at it. Worst case you will have two working motors and controllers. Then you can find an old frame and sell off the one you don't want to recover costs, or compare brushed and brushless...

[monkeychops]

Update:

I just connected up a 12V car battery charger to the motor and it spins! So maybe the motor is ok after all. I connected it to the wires that exit the controller and go into the motor.

I also checked the controller was putting out voltage when I applied the throttle (with battery connected, not the 12V charger) and my multimeter read 50V or so. So I'm slightly confused. My current theory is that the controller has broken. It was rated as 36V and 500W maximum after all and it has had 48V/1000W going thru it. The only thing I can try at the moment is to try to wire up the spare controller I bought a while back that has the 3 phase connection to the motor. I *think* the spare controller is for brushed motors. But don't really how know if it's possible to connect a 3 phase connection (with 3 prongs) to my motor which wants just - and + wires.

So if I open up the controller is there an easy way to check it? I guess there might be a burnt out component or two.

[amberwolf]

At least troubleshooting brushed stuff is easy.

If the motor works on just battery, and the controller puts out varying voltage with throttle changes, then both are working. But the connections between the two could be poor enough to not pass current enough to make the motor work.

I suppose it is possible that something is fried in the controller power section in such a way that it puts out varying voltage with throttle changes with no load on it, but cannot supply enough current for this to work with the motor connected, but I can't currently imagine what that might be. Normally brushed controllers just blow up the output stage FETs and sometimes the driver transistor(s), and most often when they do they fail *shorted* so that the motor gets full power all the time. (unlike brushless controllers, which in the same failure mode just supply power across two phases and lock the motor in one position).

If the connectors appear ok, you might post macro-setting pics of them, as close-up as you can get with them in sharp focus. If necessary, take a really high resolution pic out in daylight, then crop the pic so it's only the connector so you don't have to upload a huge file. (that's what I do for most of my pics).

[monkeychops]

Update:

When I connect the motor to the 12v car battery charger it spins (as mentionedabove) but when I turn the bike the right way round it doesn't! I've also tried this with the battery directly connected to the motor and it only spins upside down. Finally I connected up the controller again and all seemed fine, upside down, but no throttle response the right way up. Weird. With the bike on its side it initially makes a small noise but then doesn't spin.

My current best guess is that there is a magnet loose inside the motor or something similar. I haven't been able to find anybody else that has had this happen to them.

Anybody any idas?

[Ykick]

Update:

When I connect the motor to the 12v car battery charger it spins (as mentionedabove) but when I turn the bike the right way round it doesn't! I've also tried this with the battery directly connected to the motor and it only spins upside down. Finally I connected up the controller again and all seemed fine, upside down, but no throttle response the right way up. Weird. With the bike on its side it initially makes a small noise but then doesn't spin.

My current best guess is that there is a magnet loose inside the motor or something similar. I haven't been able to find anybody else that has had this happen to them.

Anybody any idas?

Doubt the magnet theory but have you checked the brushes? They do wear and behave intermittently.

[monkeychops]

The wheel and motor are still on the bike. I've had the motor open before to reconnect the power supply wires but not noticed if the brushes were visible. I don't really know what they look like. Anyway, I guess that's the next step. A pity as I was hoping it was the controller broken (easier to replace).

[amberwolf]

When I connect the motor to the 12v car battery charger it spins (as mentionedabove) but when I turn the bike the right way round it doesn't! I've also tried this with the battery directly connected to the motor and it only spins upside down.

That definitely means it's the motor itself, or a connector or wire from the motor to the power source, or something mechanical preventing spin.

Finally I connected up the controller again and all seemed fine, upside down, but no throttle response the right way up. Weird. With the bike on its side it initially makes a small noise but then doesn't spin.

If it literally only spins while upside down, and not in any other orientation (whether there is a load on it or not) you might want to carefully examine the motor, wheel, frame, etc., to ensure nothing is catching on it and preventing spin when in non-upside-down orientations, including your brakes.

Also check for wires that might be broken inside when moved to anything except a certain angle. Disconnect motor wires from any power source, then put multimeter set to Continuity (so you get a tone when it's connected) across both motor wires. Leave it that way and start moving the wires around all the way from motor to connectors; if the tone changes you have a wire problem.

My current best guess is that there is a magnet loose inside the motor or something similar.

Almost all simple cheap brushed permanent magnet motors (PMDC) use just two very large ceramic magnets in there, each covering nearly half of the circumference of the outside of the motor shell. Some (four-pole rather than two-pole) use four magnets at ~1/4 the circumference, but those are usually used only in high-torque applications at low speeds. More brushes and wiring is needed for them so they're not as cheap and so not used nearly as often as 2-pole/2-magnet.

Either way, the magnets are large and if they were loose or broken they would probably stop the motor from turning at all, even by hand. (or you would feel a grinding inside when turning by hand, but still likely wouldn't work under power).

it's possible there's a brush problem, but whatever it is is almost certainly a mechanical issue if it only works in one orientation.

To find out what you should expect to see inside, before taking anything apart, you might want to look up images of disassembled brushed motors, specifically ones like yours if you can find any. Google image search works pretty well for this.

[Samd]

Does it spin by hand boh ways up or is it physically obstructed both ways?