Ebike build in Egypt - need advice please!

[DuncanS]

Hi all,

I am looking to embark on an ebike conversion and need some assistance. I already have bikes so the project needs to work around them. I have some fairly unique challenges which I will outline below. I have an idea in my mind how to progress but am looking for advice and am open to all suggestions / recommendations. (Advisory...long post!)

Here we go:

I live in Egypt and have done for the past 10 years. That alone presents the following challenges:

1. Availablity - the whole concept of a LBC does not exist. There are a few places you can get imported Chinese bikes and a Specialized Dealer who can custom order you anything at a price! But individual spares are virtually impossible with the exception on tubes and tyres. Even a chain has to be imported! This is for normal bikes, let alone ebikes! As such all components for the build will have to be brought in. The exception is machining. Spacers / shims etc I can get machined up the road no problem.

There is 1 ebike dealer here. His communication is awful, his stock is either a Chinese ebike complete or a befang bbs01 with 36v 10Ah battery which when asked about the cell technology the answer was Lithium Chinese! So the battery chemistry is unkown as is the quality. For a 250w bbs01 with 36v 10Ah he wants 1700 usd! He will sell an individual battery and charger for 800 usd again of the unknown variety.

I have spent the last week desperately trying to find a way to get a decent battery. It is impossible. No one can ship one of these in to the likes of me. The only way to get them in is via a container where you are importing the lot so not an option. I have however found a source for LIPO in limited types available in Egypt.

2. Heat - This is potentially a massive factor. Winter time day temps are generally 16-18 deg and 12 - 14 deg at night. It has dropped to 3 deg though which is no fun for out here! Summer is the killer. It is generally 40-45 deg day and 30 deg at night. Max temp has been 52 deg I have experienced. So any system will have to battle that. In summer, only really looking at doing the commute. Winter will be the time to stretch its legs more.

3. Police - Unsure of the laws. But the police are unsure of the laws as well and can just make then up. The more it looks and sounds like a regular bike the better. Stealth a priority!

Based on that that sets 2 initial limitations in the battery department. Only option for battery are:

1. 36v 10Ah - 800 usd. Unknown lithium type, unknown cell quality, zero warranty, bloke is rude and really don't want to give him any money if I can help it....

2. LIPO power. I understand they need careful attention and am happy with that. I regularly strap a rebreather on my back with lithium batteries in a moist sealed loop, throw in a few kg of caustic chemicals, throw in some galvanic oxygen cells and disappear to 11+ bar pressure whilst breathing through all this equipment. Understanding the risks of equipment an mitigating where possible and following strict checklists are how we manage this. Applying this to LIPO batteries should not be an issue for me to deal with. Please don't read that as LIPO batteries are nothing! I mean that I have the mindset to give the batteries the care and attention they need.

When building packs from LIPO I am working on an assumption that all cells in the pack should be the same capacity. E.G. 12s2p would be 4 x 6s packs wired in a 2 x 2 configuration and all 4 should be the same capacity, say 5000. Please correct me if I am wrong.

I can get packs in the following varieties: (The prices are what they are, no way around it!)

6s1p - 5400mah 35C - 79usd
6s1p - 6000mah 50C - 106usd
3s1p - 5500mah 35C- 67usd
3s1p - 5200mah 35C - 56usd
3s1p- 4500mah 30C - 43usd
2s1p - 5400 30C - 28usd

The 2s1p 5400 and 6s1p 5400 are the same brand and also the only ones with matching capacity.

With those packs a 36v 10s could only be made from 5x 2s1p cell but more wiring! So based on that LIPO 36v doesn't seem a good fit.

12s is doable in both 6000 and 5400 and 14s is doable in 5400.

3. Buy powerbank phone slabs and reclaim cells. Potentially uneconomical as no way of telling cell type prior to opening.

In conclusion for battery I would choose either 12s or 14s LIPO. (Cheapest as if I did leave the country the battery would have to stay put.) So looking at 48v systems.


So what type of riding am I looking for.

I am 6ft 5in, 13.5 stone. I have a 2016 Specialized Rockhopper Sport 29er XXL frame size. As such I am a bit of a sail for wind!

My commute is 12.6 miles. No real traffic so fairly continuous travel. Just pottering along i have average 14mph in one direction and 8mph in the other. Can you guess which way the wind blow!!! This is my real reason for the conversion. To take this wind out of the equation and reduce effort generally in the heat. There is a total elevation change of 500ft on the commute. It basically is in 2 halves. A 7 mile steady fairly continuous climb ave 2% max 6% and then a 5 mile drop into town max 8%. Obviously opposite on way back. However on the way back the 7 mile downhill bit feels uphill due to wing which can gust to 20knots. I still want to pedal but want help! After a long day diving in the heat the ride home is too much to face in any heat. I am not looking for a motorbike though! 15mph ave would be fine as long as thats the way home. At the same time having some scope for fooling around would be a bonus! To the north there are lots of hardpacked sandy trails that are great fun but start creeping into the 12 to 14% climb area.


The Drive

All my research has been on befang middrives as they are available here although expensive if sourced here. I am now looking further a field for the motor to that is not a limit. (Only thing that has to be sourced locally is the battery.) Someone has mentioned that a hub may be a better choice for the heat. One consideration it that the bikes are wall mounted. The extra weight of a hub may not suit this. Also I will most likely convert both bikes. The other is a 26in Hardrock. That bike is not used for commuting, just by wife and mates fooling around. Having interchangable system between 2 bike would be great if there was an issue with 1. Also being able to ebike with a mate would be great. Also I am looking for a clean look and quiet operation to avoid issues with Police. Puctures are quite regular here so that is a consideration as well. The bikes are 9 speed and 8 speed so a hub would mean changing to 7 speed?

Sticking with the befang....not looking to max it out, mod it etc. Would put a 42 tooth on it. My thinking is it is better to have a larger more powerful motor running at low wattage eg only running at 50% capacity gives a bigger overhead for heat vs a smaller motor running at 80% capacity. I realise that the bigger motor has more weight and cost. The priority is longevity.

Based on that and with 48v being preferable for the batteries then that would be a bss02 or bsshd. BSS02 limited to 500w gives a third overhead. BSSHD limited to 500w gives 50% overhead plus more mass to cope with heat and larger fins to dissipate the heat. The bss02 controller issues makes me a little concerned about it in the heat. The HD appears more tolerant. On the plus side if I want more power I can adjust software. If I move to o cooler place, I can add more power etc. I also am happy to mount a temperature sensor to monitor everything.

So my plan would be 12s LIPO powering BBSHD with 42 tooth chainwheel with max current limited to 18 /20 amp.

Apologies for the essay...

All thoughts greatly received!

Duncan

 

[wesnewell]

I'd go with a 48V 1000W DD kit and run it on 12s lipo. It will have plenty of power and have a top speed of ~30mph on a 27" bike.

 

[DuncanS]

Sorry, one thing I forgot. Any kit ordered will be from em3ev as I have been in touch with then and their communication is great. I have enough communication issue this end without adding more from the other, so that may restrict choices to a degree.

I will not order from unknown places. I will not order the kit from the guy in Egypt as he is stupid expensive, doesn't communicate and frankly rude!

I am sure the US suppliers are also great but the shipping from US is more than the shipping from China.

Rgds

Duncan

 

[wesnewell]

EM3 doesn't sell a kit I'd buy, so if that's the only place you'll buy from I can't help you.

 

[DuncanS]

EM3 doesn't sell a kit I'd buy, so if that's the only place you'll buy from I can't help you.

Sorry to hear that. I had got the feeling from on here that em3ev where a good place to go. If you can recommend a reseller with good communication I am happy to look into it. A lot of my initial assumptions are from things I have gleaned off here.

Any advice re LIPO on matched capacities?

Rgds

Duncan

 

[Grizzl-E]

Em3ev is very good. I have a Mac 10t from them. Out of everyone I've ordered from they are top notch. You could run a Mac 10t on a 6 fet controller. That would give you good torque, it's a pretty small motor for stealth. And the 6 fet will only put 25 amps to the motor, on 14s thats 1470 watts max through the motor. Should be ok even in that heat.

Edit: they will supply you a nice 14s battery bms if you ask too so then you could wire that to your lipo batteries and bam! One order for everything you need.

 

[nutnspecial]

.

 

[nutnspecial]

Agreed on em3. I'd be tempted on the mac too. Would that be worse in the heat than bb02 or HD?
Duncan it appears you've done your homework imo, and stated a great case for the mid. More bikelike and versatile, and more capable of a combo of 'playin', efficient commute @ your speed pref, and hitting some decent hills. You seem aware of higher price and wearing parts.

If there's any chance you think you'd like the simplicity/price/longevity of DD at least for the commute, i'd try to procure a cheap 1kw kit to try before the second bbhd. They're like 250$ in 'murica and europe I think, and great for the money and for that app. It's similar to what Wes is using I think.

Oh yeah, def match cell capacities, and I'd go with higher cell bundles. Doing it over again with 1 or 2p, for charger I'd by a cellchecker or two, a bulk charger, and probably forego any balance charger for a 50-100$ gophert adjustable supply. Depending on pack size, a suitable gophert could bulk and manually balance. Just my 2c for charging- likely you already have something available with the lipos.

 

[footloose]

EM3ev is a solid vendor. Have ordered from them several times. Zero problems, great support.

I have both a Mac 10t and a BBS02. Like them both a lot. In your spot think I'd go with the Mac. It is a workhorse and deals very well with the type of grades you describe. The BBS02 can deal with even steeper grades, but it is inherently a little less robust, particularly because of the enclosed controller. The BBS02 might not like the high temperatures you routinely have... could be a bit more prone to cooking the controller or hall sensors on a hot day and long grade.

Re choice of batteries. A lot like choice of diving systems. If you use and service a rebreather system, then you already meet the key user requirement for LiPo: diligence and attention to detail. I'm a recreational diver, use open circuit scuba. So for me NCM or NCA chemistry lithium batteries are the better choice. They put up with a lot more casual daily abuse. I'd use LiPo if I were a bit more disciplined re maintenance.

 

[cycleops612]

Bit old now, but for the record:

good to see a build query where every dollar counts. close to my heart.

Normally a mid drive is so worth it, but given 500 feet of climb doesnt seem much, and hubs are so simple, what about the best of both worlds, a xiongda dual speed hub kit.

a low gear for hills and getting rolling, and a high one for cruising.

as above, this mid drive is ~perfection more generally

https://longyeah.en.alibaba.com/product/1273190722-214004845/26_high_quality_e_bike.html

its a wholesale link, but there must be retailers out there

check the motor in the picture, that directly drives the pedal crank.

The Killer for you is that what motor heat there is, quickly dissipates into the whole alloy frame acting as a heat sink.

sample of one, but sydney gets hot too, and my other mid drive reaally bakes on long but slight grade, and cuts out

the "bofeili" drive system other bike i have - same bike~ as the link (linked one has a better frame for batteries), never gets warm it seems.

super stealth bar the battery.

many heat issues are due to running in unsuitable rev ranges, which is solved by the gears of a mid-drive

mine is 350 watts & i am 75kg & the bike is 23kg ex battery. GVM is rated as 120kg (dont know, but most mtbS share this max i think). u r 85kg, so u have 10kg spare on this conservative? rating.

I have strong views on batteries. you are wasting your money if you get what conventional wisdom says you should get. Treat bike and battery as separate buys. the supplied ones are rubbish.

Further, u r mad if u dont get lifepo4 pouch cell battry pak. best balance of price, longevity, good discharge rates, weight.

What nobody tells you is your e.g. 36v 10ah 18650 cell li-ion battery pack, can really only deliver 350 watts for a few minutes, then it weakens and weakens during the trip. it sucks. getting any go out of more than ~70% of the claimed storage is impossible.

A battery that is supposed to deliver 360 watts per hour for an hour, does nothing of the kind. Maybe its just me, but adding overcapacity (dead weight) for your journey is not an answer.

This is not true of the lifepo4 paks as above. Their ratings seem true.

Quite so re wind being the main issue. In a test, a good roadbike takes 100 watts to do 15 mph (25kph). each extra 5kph needs another 100 watts, purely due to escalating wind resistance. The numbers vary with the bike, but the 25kph ideal figure does not.

consider a drop~ handle bars mod?

battery calculations:

So make that 150 watts for a MTB like this on the flat on smooth road at 25kph (or maybe 200w for egypt roads) then add 100w per hour for each 5kph steady speed increment. 15mph/25kph in still air & level ground we estimate at 150w. i forget, but say a 15 mile trip each way (the above example is a 360watt hour battery of course) is 150wh. On the way home, given the wind, you are really doing 35kph relative to the wind, which we estimate at 350 watt hours at 15mph roadspeed.

So in theory, a true 500wh battery should comfortably get you there at 35kph and home at 25kph.

if sand grit is an issue, it could argue in favour of a hub motor?

Similarly, the unstated catch with DD hubs is they are inevitably inefficient in many circumstances as they have no gears. So they must have disproportional power and battery.

They are also very heavy vs lighter geared down hub motors. It sure matters with airfreight costs.

as am sure u know, but others may like a natty trick the israelis used to use long ago, was a simple wire frame above & in front of rider, which a small towel was hung from, and which flapped horizontally in the wind, providing rider shade in the negev desert etc.

Calm down. I am not israeli.

u may wish to check the operating temperature specs of lifepo4/lipo/limn - i suspect lifepo4 offers best heat tolerance.

not sure, but i think higher voltage makes controller heat less an issue as their limiting factor is amps rather than watts. Any body confirm this?