Which ebike kit should I get?

[lukemiller]

Thank you so much for going in to detail and explaining this clearly.

When the charger stops and displays 'Charged' the power level reader on the battery pack shows 80%. I've uploaded a video to YouTube showing this

. I did take a DC voltage reading with my multimeter, which I think showed approx 41.6V.



Typically, one thing I didn't take a photo/video of is the info on the controller unit. I'll open the casing up and check later today.

I don't have a Watt meter but happy to buy one, as it sounds as if it'll be very handy to have. Do you have one you'd recommend please?

Luke

Hi Luke, no worries about the questions, it's what the e-bike community is for.

Lots to unpack here. First of all, how do you know you are only charging to 80%? What is the final voltage of the pack?

So you probably have a 10s 4p pack with 2.9Ah cells. This is their nominal rating, if charged right up to 4.2V and discharged maybe as low as 2.5V to get that figure, at a current of maybe only 0.5A. To start with, a lot of chargers do not go to the full 4.2V, as this shortens the life of the cell. Some experts say a cell should not be charged over 4.1V to increase cell life. Yose Power chargers only charge the pack to 41.7V, so a compromise between capacity and pack life. Then, you would never want to discharge as deep as 2.5V, as it might not accept charge again after such a deep discharge. So a BMS will usually kick in at 28V on a 36V pack. On top of that, you have the controller, which is usually set up for 30V low voltage cut out (LVC).

On top of this, discharge characteristics will depend on how fast you drain the cell and the ambient temperature. High current drain will mean you will get much less out of the pack than the nominal rating. Never recharge a pack below 0 deg C, and ideally not below 5 deg C. Discharging at 5 deg C or below will reduce your battery's output.

Anyway, assuming 10 to 20 deg C for discharge at a moderate average rate of about 100 to 150W, I expect to get about 12Ah from my 15Ah pack, so about 80% of stated capacity when charged to 41.7V. If a system is working properly, that is what I would expect.

Do you know what the LVC set up is for your controller? It might be set too high. BMSs are usually set to 2.8V or so, I wouldn't expect them to be much higher than this.

Do you have a Watt meter? Can you measure how many W hr or Ah you are getting out of the pack? What is the pack voltage when the controller shuts down?

 

[WheezyRider]

Thank you so much for going in to detail and explaining this clearly.

When the charger stops and displays 'Charged' the power level reader on the battery pack shows 80%. I've uploaded a video to YouTube showing this

. I did take a DC voltage reading with my multimeter, which I think showed approx 41.6V.

View attachment 36056

Typically, one thing I didn't take a photo/video of is the info on the controller unit. I'll open the casing up and check later today.

I don't have a Watt meter but happy to buy one, as it sounds as if it'll be very handy to have. Do you have one you'd recommend please?

Luke

Glad to be of help Luke.

It looks as if from the voltmeter reading, the battery is as good as fully charged. Put the voltmeter leads on the output of the charger, I would expect it to be 41.6V or close to that.

The reason is probably something inside the battery pack as to why the 100% LED isn't lighting up. Could be something as simple as the top LED not working.

Get a Watt meter and see what sort of Ah you are actually getting out of the pack following a full charge. If it is much less than expected, it could be because of a single bank in the pack not holding charge as well as the others, forcing the BMS to shut down the output.

I've got one of these. Probably not super accurate, but it should give you a general idea and they are cheap.

 

[ldc]

So you think it is better to get separate components and ask for some service to help me install it?

My bike is super light, it is an old school Peugeot bike that I love!

oh wow not seen a pug bike since my teens, kudos for still having one

 

[lukemiller]

Watt meter now ordered. I'll hopefully have it within the next few days so that I can test and post the results on this conversation thread.

Many thanks again for your help and great words of wisdom.

Luke

Glad to be of help Luke.

It looks as if from the voltmeter reading, the battery is as good as fully charged. Put the voltmeter leads on the output of the charger, I would expect it to be 41.6V or close to that.

The reason is probably something inside the battery pack as to why the 100% LED isn't lighting up. Could be something as simple as the top LED not working.

Get a Watt meter and see what sort of Ah you are actually getting out of the pack following a full charge. If it is much less than expected, it could be because of a single bank in the pack not holding charge as well as the others, forcing the BMS to shut down the output.

I've got one of these. Probably not super accurate, but it should give you a general idea and they are cheap.

View attachment 36057

 

[WheezyRider]

Watt meter now ordered. I'll hopefully have it within the next few days so that I can test and post the results on this conversation thread.

Many thanks again for your help and great words of wisdom.

Luke

No problem. Let us know how you get on.

If you can, you might want to change to XT60 connectors from your battery to the controller as they are much better than bullet connectors. Just make sure they are Amass branded, with a tail cap, like this:




I usually use 12AWG wire where possible, keep it as short as you can and after soldering on the connector, backfill any gap with hot melt glue to stop any water from getting in.

 

[akre2frebmtb]

I see.... I found another one check this out, have you heard of this project:

Unlimited eBike conversion kit

Add tons of capability without complexity, perfect for city bikes. Create the perfect electric bicycle with the bike you already know and love.

www.unlimitedev.com

According to what they say in Indiegogo, Ill have to wait but it may be worth it? It seems simple.

Im also, researching at separate controllers and batteries in this site from Canada:

Search results for: 'front g311 kit advanced pas custom build'

ebikes.ca

www.ebikes.ca

Cheers,

Hi.
I was looking for a conversion kit for my bike and I stumble upon the Unlimited too, it looks awesome and its very cheap.
I have a friend who has the unlimited skateboard and he said if the bike conversion kit is as good as the skate it will be amazing.
I just want a simple conversion kit, I don't want to have a lot of cables and connectors. I don't know what a BMS is and I don't want to know I just want to convert my bike to electric without the hassle of all the electronics

 

[acueductomtb]

Hi.
I was looking for a conversion kit for my bike and I stumble upon the Unlimited too, it looks awesome and its very cheap.
I have a friend who has the unlimited skateboard and he said if the bike conversion kit is as good as the skate it will be amazing.
I just want a simple conversion kit, I don't want to have a lot of cables and connectors. I don't know what a BMS is and I don't want to know I just want to convert my bike to electric without the hassle of all the electronics

Thanks man! Yes, this looks really user friendly! Did you contacted them? I may have a few questions regarding the battery and motor so I can explore further.

Cheers

 

[WheezyRider]

Hi.
I was looking for a conversion kit for my bike and I stumble upon the Unlimited too, it looks awesome and its very cheap.
I have a friend who has the unlimited skateboard and he said if the bike conversion kit is as good as the skate it will be amazing.
I just want a simple conversion kit, I don't want to have a lot of cables and connectors. I don't know what a BMS is and I don't want to know I just want to convert my bike to electric without the hassle of all the electronics

It looks interesting, but a rubber band to hold on the PAS sensor? I hope they improve that. I can see lots of them falling off, or getting pinched if the bike is left anywhere. I wonder how long the battery lasts in the PAS sensor? Would be annoying to be in the middle of a ride and it dies.

They say "high voltage battery" then say the number of Wh it has...hmmm.

So how do you control the power when you are riding? Do you have to get your phone out?

How long will firmware and app support last?

I can see it will appeal to some, but I'd rather have wires and things you can adjust/fix, but then I'm old

 

[akre2frebmtb]

It looks interesting, but a rubber band to hold on the PAS sensor? I hope they improve that. I can see lots of them falling off, or getting pinched if the bike is left anywhere. I wonder how long the battery lasts in the PAS sensor? Would be annoying to be in the middle of a ride and it dies.

They say "high voltage battery" then say the number of Wh it has...hmmm.

So how do you control the power when you are riding? Do you have to get your phone out?

How long will firmware and app support last?

I can see it will appeal to some, but I'd rather have wires and things you can adjust/fix, but then I'm old

Those are very good questions
In the FAQ it says that the pedal sensor would last between 3-6 months, I don't know if this is ok or not, but it seems to me that it's a long time.
I will contact them to see if they can answer some of those questions

 

[Nealh]

2.8v per cell group is quite low for a BMS all of mine have lvc of about 3.2v, below this there isn't much capacity to be of use. The deeper the discharge the cells suffer from more stress and heat.
4.1v max charge will increase cycle life and good cells should remain in balance, there is no reason why not to carry out a full balance charge two or three times a year just to keep them in check in case they are straying a little. I only charge to 4.1v per cell group and know from my mileage if things are right, again I find the top 0.1v hold very little mah and within about 1.6km/1 mile it has been spent.

 

[WheezyRider]

2.8v per cell group is quite low for a BMS all of mine have lvc of about 3.2v, below this there isn't much capacity to be of use. The deeper the discharge the cells suffer from more stress and heat.
4.1v max charge will increase cycle life and good cells should remain in balance, there is reason why not to carry out a full balance charge two or three times a year just to keep them in check in case they are straying a little. I only charge to 4.1v per cell group and know from my mileage if things are right, again I find the top 0.1v hold very little mah and within about 1.6km/1 mile it has been spent.

Do you know what voltage your BMS starts it's equalisation phase? Most seem to kick in at 4.15V per cell, but if you are only charging to 4.1V, does the BMS get to equalise?

 

[Nealh]

The charge balance will be at or above 4.15v per cell group as with most top cell balancing BMS. As I mentioned really good cells will remain well balanced without balance mode, it boils down to how well you know your battery and how it performs. You only need to carry out a full battery charge balance two or three times a year to make sure no cell groups stray, it is all down to how well you know your battery and how it performs.

 

[WheezyRider]

The charge balance will be at or above 4.15v per cell group as with most top cell balancing BMS. As I mentioned really good cells will remain well balanced without balance mode, it boils down to how well you know your battery and how it performs. You only need to carry out a full battery charge balance two or three times a year to make sure no cell groups stray, it is all down to how well you know your battery and how it performs.

That's good to know. What sort of bank to bank voltage variation is acceptable? With the last BMS I bought it said each bank should be within 50mV, is that about right?

When I first got into e-bikes, I thought I'd build my own pack - how difficult could it be? But then my first attempt with a cheap BMS and cheap batteries, the BMS would shut the charger down before any of the cells were balanced and it was a mess.

So I gave up and ended up buying a couple of Yose Power packs. They were ok, but one had bad soldering on the fuse and failed and the other is beginning to have problems with the key switch.

Since then I've repaired the Yose Power unit and put in a better BMS and got rid of a lot of the thin wiring and unnecessary stuff and that pack is lighter and working very well now - although I've got no idea whether the BMS is balancing it properly. Will probably do the same to the other pack at some point.

Recently I've also been playing with longer strings to increase voltage, but my early experiences with BMSs make me suspect of what will happen long term and whether the BMS is balancing properly.

Then I saw some HG2 cells going cheap - most probably fake! There were enough to make a 10s 6p pack. I've put them together with a 45A BMS (probably total overkill!) and so I can study what is going on, I've put in a terminal block on top. This means I can check at anytime whether the cells are balanced.

From what you say, I may be over thinking this one...but it will be an interesting study!

 

[acueductomtb]

Those are very good questions
In the FAQ it says that the pedal sensor would last between 3-6 months, I don't know if this is ok or not, but it seems to me that it's a long time.
I will contact them to see if they can answer some of those questions

Convinced jaja! I'm placing an order today.

It seems really simple and the price is super accessible! You can chat and ask all the questions you want. They respond relatively fast

Thanks again!