Help Mixing pouch cells

[Lucifer]

Now you can run at 36 or 48 v a motors too dumb to no voltage. What I mean by that voltage is speed you put a hundred volts on that motor it'll run in the air. but if you put it on the ground and try to push you might melt. Does the bike feel stable enough to ride at say 25 mph ? I mean is it a good bike as brakes it works you feel safe ? You could tell I'm concerned

Thank you so much, a very valid point, but while no one has mentioned safety at all, I did consider it.

First, to directly answer your question, yes first it feels that it will do it no problem. To expand the answer I also have some logic that I considered.

1) Like most folding bikes it only has 20" wheels so at slow speeds its actually less stable than a bike with bigger wheels (less Giro). Due to its constant slow speed I'm certain it will be more stable with a bit more speed due to increased Giro effect from the wheels (Bikes are more stable going at 20 mph than at 10 mph)

Also, when I first learnt to drive it was on a motorcycle not on a car (tho got a car licence later). The relevance of this being motor bike riders learn to always try and avoid impact altogether first, instinctively, only slam on the brakes as a last resort, if avoiding the objects altogether by accelerating round it isn't possible. Because a 30 mph accident in a car usually dents metal, 30mph of a bike breaks bones ...... I Know.. At about 10 mph I have zero acceleration, I don't want a sports bike, but to me the lack of acceleration feels downright unsafe. Not to mention the issues with slight gradients.... still you can guess. I feel safer on my daughters Xami scooter than on this bike due to lack of power. (And that's saying something)

2) It's a sturdy ally frame purpose built to be an electric bike, so made to take the weights of the motor and battery (unlike some conversions), Its heavier than most steel bikes. Dread to think what it would weigh if it was made of steel.

3) The manufacturers bought out a Mk3 version of this very bike that is practically identical but is 36V. When I discussed making it 36V, they mistakenly thought I wanted them to do it. They said that with replacing the rear wheel motor and the controller and rewiring the bike to fit the electronic controls that the MK 3 has it would not be economically viable. NO MENTION OF FRAME OR STABILITY OR SAFETY ISSUES, indicating the rest of the bike is the same as their current model. It's because I don't intend replacing the motor and can live without the fancy dash indicator, that makes it viable, from a safety point of view will be more or less the same as their current model, without the fancy dash display, (but I think I found one that I can retro fit for another £10 once I get it running).

4) The other 36V bike that I already got working, is a different make of bike its a FreeGo Folding E-Bike (over £1000 new), but is practically identical, in a photo you could not tell them apart.

So all things considered, I feel safe doing it, hence why my questions were all about how to do it.

Keith

 

[999zip999]

So I understand it to be a 250 w rear geared motor. Lucifer it would be nice to have a picture of both of these bikes to help identify what you actually have.
So 36v x 15a = 600watt. 48v x 15a =750w. I'm guessing the motor should be able to handle 750 Watts I guess you should try 600 first.

 

[Lucifer]

So I understand it to be a 250 w rear geared motor. Lucifer it would be nice to have a picture of both of these bikes to help identify what you actually have.
So 36v x 15a = 600watt. 48v x 15a =750w. I'm guessing the motor should be able to handle 750 Watts I guess you should try 600 first.

First to clarify I'm not modifying the one that was 36 volts at all, that is left exactly as it was. The work I did on that was to build a battery (several in fact) from various donor batteries, they are all 36 volts so direct replacement for what was there. And been doing various mechanical repairs and adjustments that you would expect on a bike that has not been used for a few years. So that one is not problem at all and is now working. The main remaining task is to encase some of the batteries, for various reasons I fitted a wooden box on the pillion so I can put various dif physical size batteries in it to test them, AND IF NEED BE, do further work on them before casing them. So that one needs no help now, it's done just finishing touches, like fitting the new brake pads I bought for it.

(I did have more than a few issues and questions about building batteries...... But they are all resolved and answered now)

It's the 24 volt one I'm still working on. That was built as a 24v e-bike by the company below,

This is the maker of the 24v Bike

They no longer make the 24 Volt version they have replaced it with this 36v version one which looks identical

This is the 36v version of what I have

It looks physically identical, except the 36v version has a handlebar electronic lcd or led display, which was not on the 24 V version, Also I just noticed they fitted a disk front brake on the 36 V version, (ironically I just bought an aftermarket one, that I was going to fit if and when I get it working). However the controller is only 24v on mine, and the motor may be 24v, it has a paper sticker saying 24v, So we must assume it is 24v (However as I stated previously I suspect its actually 36V, and looking at the two motors I cannot tell them apart)

On my bike (24 v version) the hub motor has nothing stamped on the motor, just a round sticker saying 24v, no other markings. I would take a photo, but it looks exactly the same as the current 36 v one, (motor even looks identical) so taking a photo wont really help at all. Besides the bike is already identified, I even got the manual with the bike (totally useless though no technical details at all) But that is definitely maker and model.

I did take the controller out of the frame, and photograph it and posted photos of the inside and outside of the original controller earlier in the thread. But no prob to post them again save finding them. AW said its definitely a 24v, controller, so basically might or might not take 36 volts (the caps are up to it but possibly not the FET's, and might (probably will) need modification to the lvc to take 36 Volts. So in the end I decided to buy a new 36v controller to replace the 24v one, quicker and simpler.

So that's where I'm up to waiting for the new controller to arrive, soon as its here I THINK I just have to replace the 24v one with the new 36v one, and fit one of the (now tried and tested) 36V batteries. Well that's what I think, unless I have I overlooked or misunderstood anything?

Keith

These are the pix of the original controller

 

[999zip999]

Thank you on the summary of the steps you have taken.
Now two 36v and you get 72Volt with a different controller. You might have stopped at 36 but we're not going to !

 

[Lucifer]

Thank you on the summary of the steps you have taken.
Now two 36v and you get 72Volt with a different controller. You might have stopped at 36 but we're not going to !

Not quite.

Now I will end up with two 36v BIKES both with one 36v battery in each one (I do now have several 36v batteries but never even considered putting two in series, BUT IF I DID then 2 x 36v in series would as you say be 72V.

One bike that was originally 24V will have one 36v battery but that one will need a new 36v controller.

SO.... I did stop at 36v not sure where you got the idea that I was going to but 2 batteries in series (tho your math is right). While 2 x 36v batteries in series is indeed = to 72 v (I'm Not Doing That). I will put 1 x 36 v battery in each of two different bikes so I get 2 x 36v Bikes, each with one battery.

On a previous conversation (now done and dusted) I did consider putting 2 x 36v batteries in parallel // to get more mah, but would have still been one 36v battery, with double the mah. That's turned out to be more tricky that I thought, it's not as easy as putting them in series, (see the thread to see why). I solved this problem by basically rebuilding the both these batteries as one bigger 36v battery with double the number of cells in each cell group which also doubles the mah and removes all the problems, but at the loss of the flexibility of using being able to use them separately. However it is straightforward and much less work than it sounds, basically remove 1 bms, cross link all the cell groups, with decent wires and it's now permanently one bigger 36v battery..... Job done.!

Keith

PS. I'm guessing by the misunderstanding you build really high performance bikes?
Whereas I'm a building a basic means of getting about, with a spare bike to ensure continuity of service.... LOL

PPS. That said once I get that done, I do have two other non working 36 v bikes that I was given free (cos the previous owners could not get them fixed). But what can be built by mankind, can be fixed by mankind, just not necessarily economically viable with labour costs in a shop. So I may well put these 2 bikes together as one better higher spec bike, but even then I personally would not dream of getting to 72v..........

To me it's not about being the fastest cyclist...... It's surviving to be the oldest LOL

 

[999zip999]

Well I'm still young and experimenting 65.
I got a king size bed sheet I was going to run out the cliff and see if I can make a parachute. But in the meantime.

36v x 20amps = 720 watts
72v x 10amps = 720 watts
Just joking.

 

[Lucifer]

Well I'm still young and experimenting 65.
I got a king size bed sheet I was going to run out the cliff and see if I can make a parachute. But in the meantime.

I was a mountaineer btw, and a few years ago, these videos went viral on a new sport called Liquid Mountaineering. (see video)

Liquid Mountaineering

Our local climbing club convinced people they were real, and used to tell them we were going to Snowdon National Park do a bit of climbing and L.M on lake Ogwen for the weekend, we built these stories with real detail over a couple of months, everyone believed it, some wanted to borrow a wet suit and a used pair of the essential special trainers, to come and have a go....... So we could not resist it we invented a spin off sport called "Base Diving", just like base jumping but without the chute, but using the same special trainers needed for liquid mountaineering. We went on about learning the special landing techniques needed and starting with low jumps and working our way up to the higher jumps. Not one person thought we were making it up. We got a lot of comments like you must be ****ing crazy, or rather you than me....... But not one person thought we were making it up. Apparently it's a world where all things are possible

So base jumping with a bed sheet........ Obviously totally believable. LOL

36v x 20amps = 720 watts
72v x 10amps = 720 watts
Just joking.

LOL..... Ah! there are more people with a few more years behind them experimenting with these bikes than I expected. I thought most of the people building and modifying bikes were much younger.

All the ones I see on the road in the UK, are very young (by comparison). I look at them and their bikes with an equal mixture of amazement, admiration, and trepidation. (A lot of the riders look like they have all the special qualities needed to giving base diving a go... LOL.)

Quick question, I'm mileage testing my lithium pouch cell batteries, (through a controller with a built in LVC) but now I doing lots of short 1m circular trips to see how many miles I get out of them (not so far to peddle back if the LVC cuts the battery out). I'm pleased with them, obviously I want to know how many miles they will actually do, the handle bar indicator now shows 2 bars (was 5 when fully charged, so getting close to needing a recharge).

How low would you let them get before calling the test over? The first one being so tested, so far each cell pair has dropped to about 3.65v per pair (with an actual meter), and done its done 10 miles so far (without peddle assist, just throttle). I expect the drop off to be quicker from now onwards so wondered.

How low would you let the cell voltages get in real life use, before calling it a day and recharging them?

K

 

[Lucifer]

Well I'm still young and experimenting 65.
I got a king size bed sheet I was going to run out the cliff and see if I can make a parachute. But in the meantime.

36v x 20amps = 720 watts
72v x 10amps = 720 watts
Just joking.

Oh ignore the last question unless you want to chip in, because the bike just answered it for me.

By that I mean the first part of my test route is up a gentle hill, the bike started cutting power unless I throttled back. Once the slope/hill leveled off it was fine, so I called that done, came home under power no prob. ATM I don't have a way to monitor the cells under load, (obviously the available voltage drops under load when then cells are partially discharged) but while I just worked out an easy way wire that up, I haven't done it yet. But the fact that the controller was cutting power is more than enough indication that it's time to recharge the battery.

So 10 Miles, with no peddle assisting, I hoped for more but I can live with that, and at least it still had enough to get me home without pedal power on level ground. I expect it would have needed the odd bit of peddle power and backing off the throttle if going up a gradient.

So case up this one and do the same monitored test on the other 5 that I now have.

Check out that liquid mountaineering if you haven't already seen it, there were several videos, they are convincing, even tho common sense should tell you it can't be happening LOL.

Keith

 

[999zip999]

For my purposes I don't go below 3.1 volts . Now you know I'm drawing 40 amps. I always use high quality high drain cells. My 18650 cells bak 20amp cell or spaim08 8ah cell 200amp or A123 20ah 200amp cell. I get these for high discharge for low I.R. in my mine.my controllers are 60amps max and my packs can all do double that with no sweat..So my batteries are over built for the demands I put on them . I'm old so I don't want my bike lifting the front wheel off the ground when I start or no wheelies in my programmed bikes.
My latest kit Sali budget kit 345usd everything except the battery tire and tube. 72v 60amp controller but made with soft start which I like and we'll get up to 46 miles an hour but it takes more time than my other controllers it's the way it's programmed and can't be reprogrammed being cheap.
. I'm going in for a complete knee replacement in 2 weeks. And trying to keep my knee rested to let the swelling go down. I mean I can't ride my electric mountain bike on the horse trails. Aka my ranch. Rattlesnakes raccoons skunks bobcat and other wildlife. Yeah it's the woods.

 

[Lucifer]

For my purposes I don't go below 3.1 volts . Now you know I'm drawing 40 amps.

Yeah I'm guessing that the LVC in the controller cut the power at about 3.0 v (under load, uphill) which is ok, It immediately returned power when I throttled back, As it's the first time I have experienced that, I was pleasantly surprised how it worked.

I always use high quality high drain cells. My 18650 cells bak 20amp cell or spaim08 8ah cell 200amp or A123 20ah 200amp cell. I get these for high discharge for low I.R. in my mine.my controllers are 60amps max and my packs can all do double that with no sweat..So my batteries are over built for the demands I put on them . I'm old so I don't want my bike lifting the front wheel off the ground when I start or no wheelies in my programmed bikes.

Amen to that, and I wanted to know the range so I would not unexpectedly have a long pedal home from somewhere (In actual use I will help it along a bit on hills etc, but for the test deliberately didn't). LOL

My latest kit Sali budget kit 345usd everything except the battery tire and tube. 72v 60amp controller but made with soft start which I like and we'll get up to 46 miles an hour but it takes more time than my other controllers it's the way it's programmed and can't be reprogrammed being cheap.
. I'm going in for a complete knee replacement in 2 weeks. And trying to keep my knee rested to let the swelling go down. I mean I can't ride my electric mountain bike on the horse trails. Aka my ranch. Rattlesnakes raccoons skunks bobcat and other wildlife. Yeah it's the woods.

Your place sounds awesome. (ex the diamondbacks)

I need a hip replacement, but putting it of until there is no other choice. Friend of mine had a knee replacement, took a while to be back to normal TBH, but got there in the end she calls it her bionic knee LOL. Doc says hips are easier and quicker to recover for some reason, which doesn't exactly sound logical to me, but I expect he knows. (well hope he does..... LOL).

Good luck with the replacement, and I wish you a quick recovery, just don't be tempted to do too much too soon.

Keith

PS the controller arrived today, couple of days early, just got to take the time to connect all those wires up right. Still they are all clearly labeled.....( In chinese).... So I might download an app for the phone to translate, but I think its fairly obvious after all the reading I have done.

 

[999zip999]

Take pictures of the wires and the controller will tell you exactly what each wire is for. Does it have a self-learning wire I think it does usually a single white wire in a two-pin jst black connector.

 

[Lucifer]

Take pictures of the wires and the controller will tell you exactly what each wire is for. Does it have a self-learning wire I think it does usually a single white wire in a two-pin jst black connector.

Yeah it has self learning wire, and this video shows me how to fit more or less an identical controller, and how to fit it, and how to use the self learning wires..

video on how to fit almost identical controller

So I think it's fairly straightforward, unfortunately my bike has slightly different type of plugs to the controller, as in some physically wont plug into it. I have ordered a couple of new plugs on e-bay, so I will confirm what the wires do, then change the plugs on the bike to fit. Shouldn't be a problem, just time consuming.

K

 

[999zip999]

Every time I get a controller there is connector modifications replacements are simply cut the wire. I do need a box of those white ones or I have enough of the white ones I just need the gold pins for them but when I can I change over to the jst SM connectors. But found the White 6 pin connector should stay as low voltage signal wire. The pencil headed small phase bullets are the first to go.then the mains as problem connectors. Do check for a full voltage small wire for headlight or voltage monitoring. As it's full voltage. Self learning is good but never had it. Good luck.
Careful speed is addicting quit while you can.

 

[Lucifer]

Honestly it was never about speed in that sense, just enough to be practical will do for me.

Well good new and bad news, I got the new controller connected up and working in no time, surprisingly easy.......

The bad news is the new controller is fractionally bigger than the old one and will not fit into the frame where it is supposed to go. So as it was only £10 and as I already took the old one apart to photo it for AW (when I was considering modifying it) so I know that's not rocket science, so took this apart. As I suspected there is room inside the ally box (they obviously use the same box for different boards) So having marked it out I'm going to cut a bit off the end of the box, clean it up, put it back together now 1/2" shorter, and then re fit it, before I do I will cut off some of the wires I will never use (inside the box) and put a bit of heat shrink on them. This will allow more room in the frame not having a lot of unused wires and connector plugs that are not going to be used, just taking up space.

But now this project is finally coming to an end, I do keep looking wistfully at the two proper bikes I have sitting in the garden LOL.

Keith