Hi guys, old man's attempt at getting fit!

[Bitsnpcs]

Hi guys great forum and some really interesting reading, have a voodoo hoodoo hanging in the shed, went into halffords the other day and noticed the ebike versions and I've got a few quid spare and thought what would it cost to upgrade, I am totally novice but have worked on bikes.

Any part suggestions, upgrades and general advise will be hugely appreciated.

I think it's the 2015 so 27.5 " unless mistaken, will check and confirm

 

[Deleted member 4366]

The cheapest kits cost about £500, reasonable ones are about £600 and you can get a pretty good one for £700.

You need to think about the reasons for converting a bike rather than buying OEM because there's not a massive difference in cost..

 

[Bitsnpcs]

I have to say that I am quite surprised!

Thank you so much for the reply and I can see from reading that you are a very respected member here so take your advice as gospel.

I'm surprised at the cost if I'm honest, and very glad I have resisted the urge to click the buy button on Ali etc. I understand entirely that everything has a price and of course pay cheap pay twice is a long standing truth.

So I think, for that kind of investment there are many other things that the money would be better spent on.

Thank you very much for your time and advice

 

[Deleted member 4366]

There are some quite good kits on Aliexpress and there's some bad ones too. Some of them are good and cheap. If you're thinking about any one in particular, post the details here and we can tell you the good and bad points.

 

[Bitsnpcs]

Thx D8veh

So I decided that with the little amount of knowledge that I have in ebikes, together with the years of experience running my computer store that it was a project worth experiencing at least. So here is where we are.

I bought a BAFANG 250W 36V mid drive unit kit from ebay with a C961 display

I then went about destroying my huge amount of surplus old laptop batteries to go about building my own battery (saving a good amount of cash) with little to no idea how to mount this battery safely and of course aesthetically, I hunted for a bottle battery compartment which I found mainly from abroad (UK HERE) but as I didnt want to wait I managed to procure a DILLINGER bottle battery that was faulty, after testing the cells and then replacing everything and as far as I can tell I fixed the battery.

So now I have a battery that I can only charge with my spot welder charger at 36V up to 3 amps (I use 2) until I find best place to purchase a charger (any reccos welcome)

now my spot welder charging current can only deliver 36.6V which in my mind this being a 36V battery (nominal) then it should be looking to charge up to around 40V 42V? Please do correct me if I am wrong so I think some of my problems may be that I have not got a high enough voltage charge

everything works as I expect, on flat level, even slight incline hills I am fine and its working a treat, every time I try to do a hill with any real angle I get so far up and the whole unit shuts down, LCD turns off and I have to switch the battery current off and back on before the head unit will turn on again. To add this is with me peddling also as best I can, however using the throttle alone on the flat still ended in a shut off of the system.

Now I have to add that I am no small chap, I am 6'5" and around 18.5 stone! And my initial thoughts are this 1) can the 250W even handle the weight I am talking about up hills (havent even added the bike yet) or should I have bought a more powerful set up they have 350w 36v and 500w 36v and 48v. I only bought the 250W in the first place because I thought that was the legal limit for UK, however if its not up to the job then stuff the law! And I will get a more powerful unit!

Or is it simply that my batteries are charging but not to the correct amount and therefore the motor is not getting the full voltage in the first place?

Your help will be hugle appreciated

Kind regards

jason

 

[Nealh]

Your battery you have made out of old laptop cells may be fine for a year or two but the issue of cutting out you have is because of a few issues. Any suitable 42v max 2-3a lithium ion charger will be suitable and is a must to get the best out of cells.
1. 36v battery is nominal and a full charge is 41.5 - 42v.
2. The cells will be certainly unbalanced and at only 36.6v max charge is nearly empty < 20% charge.
3. For them to balance and discharge correctly with out causing serious damage or a fire a BMS/pcb needs to be wired up to the pack.
4. Cell balancing (with BMS) happens at the top end of the charging process.
5. The cutting out is because of low voltage and either the LVC from the controller or the battery bms is doing its job, LVC is often at about 31- 34v.

 

[Deleted member 4366]

The cutting out is because you used used laptop cells. How many did you use? What type of BMS did you use? Did you test the individual cells for capacity, internal resistance and self-discharge before using them? We need that info to recommend a charger too. If you had used one of those 500w kits, you wouldn't have got off your driveway.

 

[Bitsnpcs]

Your battery you have made out of old laptop cells may be fine for a year or two but the issue of cutting out you have is because of a few issues. Any suitable 42v max 2-3a lithium ion charger will be suitable and is a must to get the best out of cells.
1. 36v battery is nominal and a full charge is 41.5 - 42v.
2. The cells will be certainly unbalanced and at only 36.6v max charge is nearly empty < 20% charge.
3. For them to balance and discharge correctly with out causing serious damage or a fire a BMS/pcb needs to be wired up to the pack.
4. Cell balancing (with BMS) happens at the top end of the charging process.
5. The cutting out is because of low voltage and either the LVC from the controller or the battery bms is doing its job, LVC is often at about 31- 34v.

Thanks for the reply

So to confirm, The battery is a rebuilt dillenger using their orginal BMS and the majority of the batteries and if it lasts 1 to 2 years then I am more than happy with that as the saving has been significant and I can easily replace again at the time, or possibly purchase new 18650 cells.

I thought I was right about the voltage, its the only thing that makes sense, I have just noticed I have an old hoverboard charger that is 42v / 2a allbeit a 3 pin socket when my dillenger is the single pin kind (think laptop) so I will chop the end of and rework the connector to use with the dillenger and see what difference that makes!

 

[Nealh]

The single DC pin plugs are two wires, the inner is the pos+ and the outer neg - , so you need to get the polarity right. Apologies if I'm teaching you to suck eggs .

 

[Bitsnpcs]

The cutting out is because you used used laptop cells. How many did you use? What type of BMS did you use? Did you test the individual cells for capacity, internal resistance and self-discharge before using them? We need that info to recommend a charger too. If you had used one of those 500w kits, you wouldn't have got off your driveway.

Hi D8veh,

Thanks for the quick reply

As I was not overly concerned on distance the amp hours available were not my biggest concern, obviously I am still in testing stage with this unit so far and will no doubt change things as I get clearer with the information, and when I fall in love with it I will want it to last for miles lol, at the moment, getting me home up the big hills will do nicely as my fitness improves!

out of the dillenger I received (STICKER SAYS 24v 10AH but sold as 36V 10AH) After opening up the battery and checking there is 10s5P (edited thanks d8veh) (so deffo 36V) I found that there were 3 packs of serials that were completely dead, i replaced those with my recovered cells and yes I tested each cell individually using a 1am draw test from full charge down to 3.2v and the readings were average 2000mah so I was reasonably happy with that.

The BMS was the original bms found inside the dillenger, I have no reason to believe this is faulty but when I have charged the battery with the hoverboard charger and got the pack up to around 40+ volts this should hopefully answer some of these questions.

Again thanks for all your help with this and I am sure there will be more

 

[Deleted member 4366]

There's several Dillenger batteries. Why don't you tell us which one?

OK, I just got your last post, so 50 cells, 10S5P. Used laptop cells are good for about 1C so 5P gives you 5 amps. I guess your controller is around 15 amps, so that's three times what the cells would be able to produce. the result would be massive voltage sag until the first group reaches LVC, which will cause the BMS to shut-off. As soon it shuts off, the voltage will recover, so you can switch it on again. Unless you build a massive battery - something like 110S10P - you'll get this sort of problem. Several of us tried it, but, to be honest, it's just not worth the effort. You can get the same performance out of a 40 decent new cells, which will give you 12Ah and last for three years or more. Cost is around £200.

Any 42v ebike or other lithium battery charger will be OK. You want around 2 amps.

 

[Bitsnpcs]

The single DC pin plugs are two wires, the inner is the pos+ and the outer neg - , so you need to get the polarity right. Apologies if I'm teaching you to suck eggs .

Not at all, I appreciate that you take the time to point these things out, you dont know what my level of knowledge is so SAFETY FIRST! I usually know where the polarisation is but if in doubt will use a meter to confirm

 

[Bitsnpcs]

There's several Dillenger batteries. Why don't you tell us which one?

It doesnt seem to have a LABEL but here are some pics I took when opening up if that helps

Sorry for the dupes. site didnt seem to tell me if the pic was uploaded or not

 

[Nealh]

Not at all, I appreciate that you take the time to point these things out, you dont know what my level of knowledge is so SAFETY FIRST! I usually know where the polarisation is but if in doubt will use a meter to confirm

After posting and re-reading #5, I realised you probably had the knowhow esp as you are able to re-ceel but no harm in keeping the post instead of deleting as the info may aid some one else.

 

[Bitsnpcs]

this is identical but cant see the other side to say the connector for the charge is the same, but looks to be it

http://dillengerelectricbikes.com.au/spares/electric-bike-kit-spares/electric-bike-kit-batteries/36v-10ah-lithium-ion-frame-battery-by-dillenger.html

 

[Nealh]

It doesnt seem to have a LABEL but here are some pics I took when opening up if that helps

The case is a generic 09 Dolphin and used by many suppliers /vendors, some chose to have their trademark/name placed on the case. Dillenger generally like to charge a lot more for their wares then other suppliers as do Cohistmotor two vendors I would avoid.

 

[Bitsnpcs]

The case is a generic 09 Dolphin and used by many suppliers /vendors, some chose to have their trademark/name placed on the case. Dillenger generally like to charge a lot more for their wares then other suppliers as do Cohistmotor two vendors I would avoid.

yes as with the link i provided 400$ aus im assuming but still 200 pounds plus and I managed to get the battery for under 50 so with reusing the old laptop cells I havent had a bad deal, assuming it lives up to what I want.

Out of interest Nealth do you happen to know of a supplier that sell the generic cases? and or BMS? I did already purchase a cheap BMS from ebay that I used in my very first prototype but I am assuming these are not the best going forward?

 

[Nealh]

this is identical but cant see the other side to say the connector for the charge is the same, but looks to be it

http://dillengerelectricbikes.com.au/spares/electric-bike-kit-spares/electric-bike-kit-batteries/36v-10ah-lithium-ion-frame-battery-by-dillenger.html

The standard charge jack/socket is usually a dc 5.5 x 2.1.

 

[Nealh]

This is the only place I know of , though possible might be some on aliexpress as they are China manufactured.
https://bmsbattery.com/56-case

UK seller of said battery type are Woosh bikes and Eclipse bikes but not cases to name but two.
Battery constructor Jimmy @Insat intl/BGA reworking may have empty cases not sure if he would sell the case only.

 

[Bitsnpcs]

There's several Dillenger batteries. Why don't you tell us which one?

OK, I just got your last post, so 50 cells, 10S5P. Used laptop cells are good for about 1C so 5P gives you 5 amps. I guess your controller is around 15 amps, so that's three times what the cells would be able to produce. the result would be massive voltage sag until the first group reaches LVC, which will cause the BMS to shut-off. As soon it shuts off, the voltage will recover, so you can switch it on again. Unless you build a massive battery - something like 110S10P - you'll get this sort of problem. Several of us tried it, but, to be honest, it's just not worth the effort. You can get the same performance out of a 40 decent new cells, which will give you 12Ah and last for three years or more. Cost is around £200.

Any 42v ebike or other lithium battery charger will be OK. You want around 2 amps.

AHA mathimatical messup here i see

I got the P and S mixed up so yes the batteries were tested on a 1 amp draw from full charge down to 3.2v cutoff, and the average was around 2000mah (2ah)? so my battery should be 10s, 10 x 3.6v = 36 volts and 5P, 5 x 20 = 10ah

Also I am assuming that is giving us approx 360 watts of power? not much more than the 250W needed? So, is it worth me byuying brand new high mah 18650s and building a brand new pack?

3500-mAh, NCR18650GA, Panasonic-Sanyo something like this maybe?