Is anyone familiar with Ezee 36v bikes? Can I use a 44v batt

[HypnoToad]

Can I use a 44v battery without killing anything?

I recently bought a used Ezee Forza and I feel a little out of depth as its my first e bike.

I got the bike cheap as it had no battery, so I'm making my own out of used laptop battery packs.

Now the laptop battery packs are 2p 4s, so if I keep the packs in 4s configuration then I can go for 12s 18650 Li ion which will give a voltage of 44v when in use and around 50v hot off the charger.

Will this be too much for the Ezee speed controller and hub motor? Or will it be ok. Thanks.

[dogman]

Likely to be OK. Generally you see 50v capacitors or 63v capacitors inside 36v controlers. So 50v max ought to be ok.

But laptop cells make poor ebike batteries. You need a lot of cells to provide 20 amps without killing off cells.

[HypnoToad]

Likely to be OK. Generally you see 50v capacitors or 63v capacitors inside 36v controlers. So 50v max ought to be ok.

But laptop cells make poor ebike batteries. You need a lot of cells to provide 20 amps without killing off cells.

Thanks, looks like I may just about get away with a 12s pack, in fact my charger slightly undercharges each cell as I measure 4.072v on each cell after balance charging so my pack should be around 49v hot off the charger. I'll measure the fully charged pack anyway just to be sure.

Hw easy would it be to open up the controller? I downloaded the manual for my bike and it said the controller was weather sealed, so I imagine this would make it a pain to see what capacitors they had used? If it was easy I'd be happy to replace any 50v caps with 63v or even 85v equivalents.

Also regarding laptop cells, I know that they aren't ideal, so I'm paralleling them up in order to get a good amount of current out of them. Each cell is a li ion Samsung 2600mah 18650, and my pack is going to have 6 of them in parallel so I will have 15.6Ah in theory.

Now discharging at 1c I will get around 15 amps, and I'm told these cells are good for 2c so 30 amps will be my upper limit. Now as I said in my first post I'm a newbie to all this so please correct me if I'm wrong here as the last thing I want to do is kill my battery lack which I've spent ages soldering together. I can parallel up 8 cells if I need to or will 6p ok here? 12s 8p will end up being a pretty big pack...

Thanks.

[gorach]

My bike is running on 50v lipo (hoc) with a 36v controller and 50v capacitors just fine.

[dnmun]

HT, isn't it really expensive and heavy to build a pack out of these small cylindrical cells? why not buy the hobby king lipo packs instead?

but if it is already done, and you wanna know what the caps are inside the controller, you can ask justin who sells the controller i think. ebikes.ca

12S lipo is 50V so even if it has 50V caps you should have no problems. if they blow up then you can replace them.

[dogman]

I can't say about a particular laptop cell. I just have read where others have said they sag badly unless discharged at .5c. I don't know what brand that was though. Older stuff from 3-4 years ago was that bad for sure.

Makes a big difference if you are getting those cells nearly free. If not, look at RC hobby lipo for sure. Hobby King has some good prices.

[HypnoToad]

^ I guess the only way to find out it to just build the pack and try them out. I'm going to have a voltage readout on the handlebars, so I can see how much sag I get. The uk model only has a 250w motor so I can't see it drawing more than 15 amps even with a little over voltage. If anything a little sag may help my controllers caps if they are 50v

Once it's all soldered up I'll upload a video of how much voltage sag as I get up a hill.

My bike is running on 50v lipo (hoc) with a 36v controller and 50v capacitors just fine.

Good stuff, thanks.

HT, isn't it really expensive and heavy to build a pack out of these small cylindrical cells? why not buy the hobby king lipo packs instead?

but if it is already done, and you wanna know what the caps are inside the controller, you can ask justin who sells the controller i think. ebikes.ca

12S lipo is 50V so even if it has 50V caps you should have no problems. if they blow up then you can replace them.

Well, as far as cost goes it depends. If you were to buy new cells at $5-$10 a throw then a 72 cell pack like the one I'm building would turn out to be rather expensive.

Now I managed to get a job lot of laptop batteries that are all the same model battery packs for next to nothing, and all of the packs I have opened so far contain the same cells, so I'm not mixing brands and capacities.

It is taking rather a long time for me to build this pack however, as I'm learning as I go along and I'm balancing each pack before paralleling them up, so the main costs here is my time. However it's sunny out at the moment I could think of worse things to be doing.


I'll get hold of Justin at ebikes.ca, I remember seeing some old posts on here about how 48v packs may or may not work with modded 36v ezee controllers from him, so if anyone would know, he would.

Finally I tried to take apart the controller today, it seems to be bonded together, so if the caps to blow, it may be easier to change the controller instead of the caps.

[SamTexas]

Now discharging at 1c I will get around 15 amps, and I'm told these cells are good for 2c so 30 amps will be my upper limit.

Yes, at least one manufacturer (Panasonic) tell us that they are good for 2c. In fact Panasonic shows actual charts of their cell discharging from full to empty at 2c rate. What they fail (or choose not) to show is how hot the cells get at that discharge rate.

So 2C is ok for very very short bursts (30 secs max) followed by long rest time. Even 1C continuous is pushing the limit of these cells. The best continuous discharge rate is 0.5C or less.

Laptop cell is excellent for pedal assist ebikes. If you're willing and capable of providing at least 1/3 of the total power required to ride at any speed, nothing beats the high energy density of laptop cell.

Laptop cell is poor choice for "fake" ebikes. I mean those that still have functioning pedals but are never used.

[kevo]

gorach wrote:

My bike is running on 50v lipo (hoc) with a 36v controller and 50v capacitors just fine.

Did you have to make any changes to the controller or other parts of the bike for it to work out?

[docnjoj]

You may want to check out DrBass and darkangels threads on battery builds. Also pwbset threads.
otherDoc

[HypnoToad]

Now discharging at 1c I will get around 15 amps, and I'm told these cells are good for 2c so 30 amps will be my upper limit.

Yes, at least one manufacturer (Panasonic) tell us that they are good for 2c. In fact Panasonic shows actual charts of their cell discharging from full to empty at 2c rate. What they fail (or choose not) to show is how hot the cells get at that discharge rate.

So 2C is ok for very very short bursts (30 secs max) followed by long rest time. Even 1C continuous is pushing the limit of these cells. The best continuous discharge rate is 0.5C or less.

Laptop cell is excellent for pedal assist ebikes. If you're willing and capable of providing at least 1/3 of the total power required to ride at any speed, nothing beats the high energy density of laptop cell.

Laptop cell is poor choice for "fake" ebikes. I mean those that still have functioning pedals but are never used.

Great info, thanks. My Ezee Forza does have a sensor on the cranks that tells the controller when you are pedalling. If you do not pedal then no power is supplied to the motor. In fact there is no throttle on this bike, just a knob you turn which dictates the amount of pedal assist.

I'm coming from a non powered bike so I'm reasonably fit, so hopefully I won't have any issue providing 1/3 total power, even though I don't have anything like cycle analyst right now to determine my power usage while riding.

I'll look into maybe having more cells in parallel if my 6p pack sags too much, as I have almost 300 cells to play with; the main reason I went for 6p was the fact that I'll be able to use the existing Ezee battery mount below the seat post.

Also the power density is good, one of my 4s 6p packs weighs around 1.4kg and is around 300Wh.

You may want to check out DrBass and darkangels threads on battery builds. Also pwbset threads.
otherDoc

Ok, cheers, I'll check em out. Right now I'm building 3 separate 4s 6p packs, then I plan to daisy chain them once they are mounted on the bike. I have 2 out of 3 already made up, and it would be nice to see how some others have done it, as there are little things that can be a pain to deal with when making a pack.

[gorach]

gorach wrote:

My bike is running on 50v lipo (hoc) with a 36v controller and 50v capacitors just fine.

Did you have to make any changes to the controller or other parts of the bike for it to work out?

Nope. 4*6s lipos replacing stock 36v lion, inline fuse and switch, turnigy wattmeter. Controller as is with 50v capacitors.

[HypnoToad]

gorach wrote:

My bike is running on 50v lipo (hoc) with a 36v controller and 50v capacitors just fine.

Did you have to make any changes to the controller or other parts of the bike for it to work out?

Nope. 4*6s lipos replacing stock 36v lion, inline fuse and switch, turnigy wattmeter. Controller as is with 50v capacitors.

Nice, I'm almost done making my pack now and I'm running a pretty similar setup to you, sans the wattmeter. I'm planning to have a simple voltmeter however, so I should be able to see how much sag I'm getting.

[SamTexas]

Great info, thanks.

You're welcome.

Also the power density is good, one of my 4s 6p packs weighs around 1.4kg and is around 300Wh.

That would be energy density (not power). You have made a mistake in calculating your capacity. Assuming your cells have an average 2.0Ah capacity: 6*3.7*2.0*4 = 178Wh. You also made a mistake in calculating the weight. Your 4s6p pack consists of 24 cells and should weigh around 1.1kg.

[HypnoToad]

^ Each pack of 8 cells claims to be 75Wh, but I didn't compensate for the reduced capacity that comes with age. Also I weighed my batteries, but they did also have a lot of electrical tape, connectors, etc. which probably explains why my weight was a little off also.

Anyway, I've finally finished building the 12s pack, and my Ezee controller doesn't seem to work with it.

I get 7 blinks from the LED, and after looking at the user manual for the Torq, it seems 44v is the upper voltage limit for this controller.

Now, is there an easy way around this?

Would replacing the controller be an option?

If so what controller would be a good replacement?

THanks.

[SamTexas]

Anyway, I've finally finished building the 12s pack, and my Ezee controller doesn't seem to work with it.

I get 7 blinks from the LED, and after looking at the user manual for the Torq, it seems 44v is the upper voltage limit for this controller.

Now, is there an easy way around this?

First you need to determine its ACTUAL upper voltage limit. You can do it with your existing 12s pack:
Discharge your pack down ONE volt at a time. 50V => 49V => 48V ... => 43V => 42V (3.5V/cell). After each one volt reduction, try it with your controller. Stop when your controller is happy (no more blinking). That's your actual upper limit. Divide that voltage by 4.20V, the floor (truncate) of the result is the maximum number of cells in series your controller can accept.

Ex: 47V actual upper limit. 47/4.2 = 11.19. Floor [11.19] = 11. ==> 11s is the correct pack for your controller.

[HypnoToad]

Anyway, I've finally finished building the 12s pack, and my Ezee controller doesn't seem to work with it.

I get 7 blinks from the LED, and after looking at the user manual for the Torq, it seems 44v is the upper voltage limit for this controller.

Now, is there an easy way around this?

First you need to determine its ACTUAL upper voltage limit. You can do it with your existing 12s pack:
Discharge your pack down ONE volt at a time. 50V => 49V => 48V ... => 43V => 42V (3.5V/cell). After each one volt reduction, try it with your controller. Stop when your controller is happy (no more blinking). That's your actual upper limit. Divide that voltage by 4.20V, the floor (truncate) of the result is the maximum number of cells in series your controller can accept.

Ex: 47V actual upper limit. 47/4.2 = 11.19. Floor [11.19] = 11. ==> 11s is the correct pack for your controller.

Ok, my charger does take a long time to discharge my pack, as it can only do it at around 1-2 amps. I'm discharging the pack right now and will try it with 48v, 47v, 46v, etc. and see where the high voltage cutoff is.

I also have a 10s 4p pack that I have used for testing in the past and this did work when charged to 4.1v per cell, the total pack voltage was 40.85v hot off the charger, so the controller is ok with that.

However the front wheel no longer seems to spin when I have my 10s 4p pack connected, so I'm thinking that there may be a wiring issue somewhere, which is a pain. I did have to remove the cranks in order to install the controller on the battery bracket, so it's possible there is a problem with the pedal sensor. Sometimes it tries to spin the wheel and then just stops less than 1 second later, I'll try and get a video if I can as it's hard to explain what's going on.

I really want to use a 12s pack if I can, even if I have to replace the controller as I've seen a few threads on here where people Infineon/ ecrazy man controllers successfully on Ezee bikes.

[Ypedal]

The early eZee kits from ebikes.ca would not allow 48v packs, ( HVC ) , but the current generation controllers do, so i'm sure it can be modified somehow because the controllers are the same, just allowed to run higher voltage.. i dont know if it's a programmable option or just a simple resistor swap on the circuit board..

[SamTexas]

I really want to use a 12s pack if I can, even if I have to replace the controller as I've seen a few threads on here where people Infineon/ ecrazy man controllers successfully on Ezee bikes.

That would be fine as long as you do your homework ahead of time to make sure the new controller is capable of supporting your pedal assist sensor's signals. Also make sure that the controller can support higher voltage than 12s. Before long, you'll catch the speed bug and will want to run at 14s, 16s, ...

[richmpdx]

Hypo,
As you suggest you can certainly replace the controller. On my Ezee Torq I replaced the controller and I am running a 48v system by using a 12v 10ah battery in series with the Ezee battery. Adds a little more top end speed, but that wasn't really my goal. It helps quite bit with hills. The additional battery also modestly increases total watt hours. In my case, I eliminated the pedal activated system and I am just using a throttle. But you can certainly use a controller that supports PAS.
Rich

[HypnoToad]

The early eZee kits from ebikes.ca would not allow 48v packs, ( HVC ) , but the current generation controllers do, so i'm sure it can be modified somehow because the controllers are the same, just allowed to run higher voltage.. i dont know if it's a programmable option or just a simple resistor swap on the circuit board..

I see, hopefully it's a resistor swap as I'm happy enough with a soldering iron. I haven't managed to open my controller until today, and it is quite tightly packed in there. It has 6 FETs, but I haven't googled the model numbers yet, as I've been doing some research and it seems some sellers fit 4110 FET's to the 48v upgraded controllers, so if it's just a straight swap then I may to that also.

However, I managed to brake the PCB of my Ezee controller by using mounting bolts that are too long for the controller. I didn't see the damage until I opened the controller. I'll grab some photos when I can, the damage isn't too bad and it does explain why I've been having trouble with my 10s pack let alone my 12s pack. I was getting 11 LED flashes, which is thermostat error according to the manual.

I really want to use a 12s pack if I can, even if I have to replace the controller as I've seen a few threads on here where people Infineon/ ecrazy man controllers successfully on Ezee bikes.

That would be fine as long as you do your homework ahead of time to make sure the new controller is capable of supporting your pedal assist sensor's signals. Also make sure that the controller can support higher voltage than 12s. Before long, you'll catch the speed bug and will want to run at 14s, 16s, ...

I've done some research and even made a spreadsheet of what pack will give what wattage, and I think 12s would be a good limit for both my motor and battery pack, I think 16s may be pushing a bit as the eZee motor has nylon gears inside and the extra torque may be too much.

I've just ordered a this cheap 48v controller:
http://www.ebay.co.uk/itm/290621145469#ht_3490wt_907

I'm hoping that it's possible to adjust or disable the low voltage cutoff that some of these 48v controllers have as I think they are setup for 13s packs and my 12s packs may not be high enough voltage. I'll have to cross that bridge when I come to it.

Hypo,
As you suggest you can certainly replace the controller. On my Ezee Torq I replaced the controller and I am running a 48v system by using a 12v 10ah battery in series with the Ezee battery. Adds a little more top end speed, but that wasn't really my goal. It helps quite bit with hills. The additional battery also modestly increases total watt hours. In my case, I eliminated the pedal activated system and I am just using a throttle. But you can certainly use a controller that supports PAS.
Rich

Keeping PAS would be nice but not essential. Can I ask what controller you are using and where you mounted it? I've been thinking that I could mount the controller below the rack if it's much bigger than the eZee controller.

[richmpdx]

I am using the Grin Cyclery (aka ebikes.ca) 24-48V, 20A controller. So it is their variation of the Infineon controller and should support PAS, I just didn't take the time time to figure out how to set it up. I liked the PAS that came with the original setup of the Torq, I think it is quite convenient. Please post if you set up the PAS, I may give it a try. The replacement controller mounted in the same place as the original Ezee controller.
Rich

[dnmun]

if you order a 48V controller then the LVC of the controller will shut off the motor when the pack is drawn down to about 40.5V.

if you are using a 12S lipo then the pack would only be partially discharged so you would never get the full capacity outa the pack.

[SamTexas]

if you order a 48V controller then the LVC of the controller will shut off the motor when the pack is drawn down to about 40.5V.

Not always though. It varies from one controller to another. I have a 48V, 35A controller from ebikes.ca and the lvc is 27V.

[HypnoToad]

I am using the Grin Cyclery (aka ebikes.ca) 24-48V, 20A controller. So it is their variation of the Infineon controller and should support PAS, I just didn't take the time time to figure out how to set it up. I liked the PAS that came with the original setup of the Torq, I think it is quite convenient. Please post if you set up the PAS, I may give it a try. The replacement controller mounted in the same place as the original Ezee controller.
Rich

It's nice to know an Infineon controller with fit in the same place as the Ezee one. I'm still waiting for my controller to arrive so it will be a while before I will be able to try PAS, but it would be nice to keep it if possible. I think I may order a twist or trigger throttle for the Infineon controller, as the current knob throttle may be a little odd if I don't get working PAS.

if you order a 48V controller then the LVC of the controller will shut off the motor when the pack is drawn down to about 40.5V.

Not always though. It varies from one controller to another. I have a 48V, 35A controller from ebikes.ca and the lvc is 27V.

I understand that some of these Infineon controllers are reprogrammable? I guess this would then allow me to adjust the LVC? If not 40.5v would be ok, as long as the voltage sag from my pack didn't hit this voltage. Even so with a 12s pack that's around 3.3v per cell so my 18650's would be pretty drained by that point anyway.

Today I tried and failed to fix my current Ezee controller, as it used to work fine with my 10S pack until I tried to mount it with the wrong bolts.

Now that I eventually have it apart I can also check the capacitors, mosfets, etc. also. Here's a photo of the top of the PCB, click on it for higher res:


C37 - The big tank cap in the top right is 63v 470uF
C27 C28 C29 - The smaller caps below the FET's are 50v 10uF - these can be easily swapped out for 63v versions.
C38 - The capacitor by the power wires is 63v 47uF
C25 - The capacitor to the right of R30 and R31 is 25v 47uF. However it has +15v written on the PCB above it.
C12 - The bottom left capacitor behind the blue wires is 25v 10uf
C15 - The bottom right capacitor behind the yellow and res wires is 25v 10uf

Also, the FETs are STP75NF75, they're rated for 75v, so no worries there. There is also a microcontroller at the bottom, PIC16F73, which I guess contains the high voltage cutoff settings. Reprogramming it is beyond me, but I may see what voltages are on the 3 analogue input pins while the unit is on, as I'm sure it must go thru a resistor or two.

Here's what using the wrong mounting bolts did to the PCB:

A track is broken on the bottom left, I can bridge this with some wire, and the PCB is also cracked on the right here the FETs are mounted. Now even though it's cracked, the tracks seem ok, but I'm going to try and add some wire to that thin track between the phase wire holes.

Hopefully if I can get this working again with my 10S pack I'll then have another go at trying to raise the high voltage cutoff.