Second long trip on self-build bike

[morphix]

Today I did my second long trip on my self-build 250W 36V bike to try and flatten my LiFePo4 5Ah battery..

I covered 22km, just over 13 miles...about the same distance I did on my last trip.. I did charge the battery for an hour and half this morning before setting off.. I wish I hadn't, as that kind of mucks up the test.

Anyway this was an interesting trip in more ways than one..

I started off with a trip to a local lake which is 1.2km away...the distance around the lake (nearly all flat) is 3km and so I thought it would be an ideal opportunity to test the speed of the bike kit. I went around it in 7 minutes using the highest pedal assist setting and pedalling constantly..although I had to stop or slow down quite a few times for people walking dogs. I reckon the actual time would of been 5 minutes without stopping. 3km in 5 mins works out at 36 km/h, which is 22mph! The built-in speedometer is fairly accurate then.

Next I went on a dual carriageway and some fairly busy main roads in town with plenty of buses..I was using pedal assist on full power still, had no problems pulling off at give ways and overtaking traffic. If I was riding an unassisted bike I definitely wouldn't feel as confident about being on such busy roads.

I came to this ridiculously steep hill and tried to go up it first in pedal assist and then on throttle (from a standing start at the start of the hill), but the motor just cut out and my LCD gave me a warning message..it had cut out to protect the system. Heh. I had to power off/on the system to get it back on which was a bit scary but thankfully it came back on again.

Next I went cross-country along some muddy paths, through a field, then across a golf course, and soon wished I hadn't as the ground was very soggy with the bike (and myself) soon covered in mud!! Nevertheless the bike handled the gravel paths and soggy ground effortlessly using throttle mode. Stopped for a bit to have a cheese sandwich and enjoy the stunning views, but was soon besieged by ducks that came out of the water and approached me bold as you like! After feeding the ducks I decided to start heading back... my power level was down to 3 bars and I really needed a shower..mud was literally all over me, on my face and in my hair!

I was about 3 miles from home when the pedal assist stopped working..I soon realised I had broken one of the wires on my improvised wiring (awaiting some proper DIN plug & sockets)..so I had to pedal back using throttle mode.. when I got about 500 metres from my flat the battery started to finally give up...as soon as I came to even a slight raised part of the road the motor would cut out and give a warning.. The LCD battery indicator was down to 1 or 2 bars..

As soon as I got back I gave the bike a good wash and had a much needed cup of tea!

Summary...

Today I was out for 1 hour and 23 minutes. The 5Ah battery gave 43 km / 26 miles from full charge (that is for both trips), but that was with a short 1.5 hr top-up charge between trips. I reckon it would of done 18-20 miles without the top-up charge. I was pedalling a fair bit but also making almost constant use of pedal assist (mostly at highest power level) and occasional use of throttle, except for the last 3 miles home when I used the throttle nearly continuously.

Few observations...

As I said before in my first long ride post...I definitely find pedal assist much easier and faster compared to throttle. The power is much smoother and controlled when starting and stopping.

Pedal assist also seems much more battery friendly (particularly on hills) as whenever I used throttle the indicator would drop down to 2 bars.

-----

I'm really impressed with the performance of the little 5Ah battery. My expectations were quite low and I expected about 10 miles round-trip. However based on this test, I would be quite confident now doing a 20 mile round-trip on a single battery, or 40 miles with my backup battery on a rack!

As the weather looks set to be great tomorrow I will charge the battery to full tonight and do another morning trip just to confirm I can get 18-20 miles on a single charge...

 

[deadmonkey]

Good work, both on the build and the documenting of your trip

 

[jerrysimon]

Nice write up and pics, thanks for that.

The first few rides really transform you view of cycling together with giving you that sense of freedom by visiting places that you just can't take a car.

Plus no traffic jams

Regards

Jerry

 

[morphix]

Nice write up and pics, thanks for that.

The first few rides really transform you view of cycling together with giving you that sense of freedom by visiting places that you just can't take a car.

Plus no traffic jams

Regards

Jerry

Oh it certainly does! It's an amazing feeling of freedom as you say. I'm already planning longer trips to new places

 

[morphix]

Good work, both on the build and the documenting of your trip

Thanks, I will do another post shortly showing how much it cost and where I got everything.. I've been waiting until the bike was completely finished as I still have a few more things to get..tyres, mud guards, rack and also I need to tidy up the wiring, make an enclosure for the battery and finally, adapt the handlebar bag for quick release...

 

[Deleted member 4366]

Nice write-up. Its nice to see how different installation perform. Just a suggestion: Unless you do serious off-roading, you should try road tyres. Those knobblies are probably sapping about 15% of your energy. I'm sure everybody'll reccomend their favourites, but if you want to fly, try Schwalbe City Slicks. They roll and roll (some say they roll uphill!), but are a bit more puncture prone than what you have.

 

[morphix]

Nice write-up. Its nice to see how different installation perform. Just a suggestion: Unless you do serious off-roading, you should try road tyres. Those knobblies are probably sapping about 15% of your energy. I'm sure everybody'll reccomend their favourites, but if you want to fly, try Schwalbe City Slicks. They roll and roll (some say they roll uphill!), but are a bit more puncture prone than what you have.

Phew you guys have a habit of reading my mind! I was just thinking the very same this morning and wondering what type of tyre to order! The City Slicks sound good but I'm always worried about punctures, particularly with going longer journeys..there's so much glass on the roads around here...also, I live in a semi-rural area with plenty of off-road gravel paths I'd like to use in summer...what do you recommend?

 

[tangent]

Schwalbe Marathon Plus seem to be the best puncture resistant tyres. I have been using them for about 6 months (1500 miles) and so far no punctures.

Where did you get the battery?

 

[morphix]

Schwalbe Marathon Plus seem to be the best puncture resistant tyres. I have been using them for about 6 months (1500 miles) and so far no punctures.

Where did you get the battery?

Thanks for the recommendation.. I got the battery from a Chinese business selling on eBay... cost £83 with BMS and a charger including shipping by FedEx.. a few other people have bought for him before me and vouched for him..

daoji666 items - Get great deals on Sporting Goods, Consumer Electronics items on eBay UK!

 

[jerrysimon]

Thanks for the recommendation.. I got the battery from a Chinese business selling on eBay... cost £83 with BMS and a charger including shipping by FedEx

Wow that's a good price

My DIY 36v, 2.3Ah batteries cost £60 without BMS or charger. Will be interested to see how well your battery performs, but at that price its worth a try for sure.

PS is that a 24v or 36v battery ? Ah just checked your original post and its 36v as I said thats a good price.

Regards

Jerry

 

[morphix]

Wow that's a good price

My DIY 2.3Ah batteries cost £60 without BMS or charger. Will be interested to see how well your battery performs but at that price its worth a try for sure.

PS is that a 24v or 36v battery ?

Regards

Jerry

Yes not bad at all is it. I had to pay a bit of duty/VAT which was £5.83 (plus the usual extortionate £10 "handling fee" to FedEx of course!).. other batteries have been in use about 6-7 months+ now I think in the forum...Oldtimer was one of the first to buy one from this seller and says his are still working fine..

Mine is a 36V but he will do 24V or 48V and can build the battery to your own requirements (for Ah and size) if you don't see what you want listed..He doesn't make any extra charge for doing custom orders..

The batteries I had are cube shaped, 14cm(l) x 10.5cm(w) x 10cm(d) weighing 1.83kg.. my thinking behind having these smaller batteries was to keep the weight down on my folding bike as I live in 2nd floor flat! I also wanted to make them light enough to remove and carry when the bike is parked.. As they were so cheap I got two which doubles the range for longer journeys (I can carry a spare on rack and swap them).

The batteries themselves have no outer-casing, they are wrapped in strong silver electrical tape.. I'm looking for a suitable ABS plastic housing just for a bit of extra protection.. The charger is quite large (but very light) and is fan cooled..

 

[morphix]

There has been a comment made that I should be looking at different battery technology for such a small battery which might give better performance...(presumably Li-Ion)..

I'd be interested to compare if I can find a small Li-Ion... I did see one on AliExpress a few months ago which was 36v 8Ah 2.6kg for $230 but I can't find the seller now..

 

[jerrysimon]

There has been a comment made that I should be looking at different battery technology for such a small battery which might give better performance...(presumably Li-Ion)..

Are these not already Li-Ion ?

I guess at 5Ah then they will be current limited, compared to larger capacity one and might be why the BMS is set to cut out on excessive current load ?

The beauty of the A123 cells I use, is they will cope with 70amp plus, peak current draw without much drop in voltage.

Actually rechecking the link they are LIFEPO4 which have a reputation for lasting longer than Li-Ion in terms of charge/discharge cycles, but as suggested I guess max current draw is limited with these smaller capacity batteries.

Regards

Jerry

 

[morphix]

Are these not already Li-Ion ?

I guess at 5Ah then they will be current limited, compared to larger capacity one and might be why the BMS is set to cut out on excessive current load ?

The beauty of the A123 cells I use is they will cope with 70amp plus, peak current draw without much drop in voltage.

Actually rechecking the link they are LIFEPO4 which have a reputation for lasting longer than Li-Ion in terms of charge/discharge cycles, but as suggested I guess max current draw is limited with these smaller capacity batteries.

Regards

Jerry

You are probably right Jerry, I must bow to your experience being fairly new to the scene.. I guess it depends how you want to ride and how much weight you're pulling... I'm quite light (just over 9 stone) and my bike is 20kg (including kit), I prefer to ride on pedal assist too and don't mind putting in plenty of effort as I'm fairly fit.. I think if you used a small battery like this on just throttle and you were much heavier with a bigger bike, you wouldn't get anywhere near the mileage I got so far.. Horses for courses as they say.. the beauty of electric biking is you can tailor your own set up to your own needs and requirements..but this build of mine just goes to show, for some people you don't need massive power and big batteries to get a very good distance from small economically priced batteries..

 

[jerrysimon]

I am certainly no expert and have learnt most of this stuff from the gurus here.

I think your summary, in the last post, is a good one though.

My EBrompton is very much built around my exact requirements i.e. carry least amount of weight battery wise, for a fairly flat 10 mile round commute. The small light Tongxin motor I use is also no power beast and thus does not suck out lots of capacity, but does expect a little pedaling effort to balance things out

Regards

Jerry

 

[morphix]

I am certainly no expert and have learnt most of this stuff from the gurus here.

I think your summary in the last post, is a good one though.

My EBrompton is very much built around my exact requirements i.e. carry least amount of weight battery wise, for a fairly flat 10 mile round commute. The Tongxin motor I use is also no power beast and thus does not suck out lots of capacity but expects a little pedaling effort to balance thing out

Regards

Jerry

I also had planned to go for a 20" folding bike initially, as light as possible.. but then I saw this 26" full-size folding bike which was only 14.5kg and not much different in terms of weight to 20" folding bikes in my budget...plus it was cheap at £150.. as this was my first build I decided to try that bike first...the plan was to sell it on and build another 20" bike after.. The 26" bike is still too large really for storing in my flat with limited space.. the stairs are just about tolerable but it's already picking up a few knocks.. 20" would be more practical I think, if I can get used to riding such a small bike!

I'm pretty sure my motor is also a Tongxin like yours (it's the same motor I'm told as used by Electric Wheels Company)... I got it in kit form from rftech in Austra and it came with the same LCD/controller as used on the 20" Wisper bikes.. my motor sounds on a par with yours in terms of power, it will pull you along nicely at a good speed if you pedal a bit and most hills are no problem with pedal assist, but it does struggle sometimes on throttle and lacks power even on the flat, at least with my smaller battery.

The motor says rated 13A max rating and 220 RPM.. it's a lot quieter than some motors I've heard which is a good bonus.

 

[jerrysimon]

I'm pretty sure my motor is also a Tongxin like yours (it's the same motor I'm told as used by Electric Wheels Company)... I got it in kit form from rftech in Austra

Interesting.

Can you give more details of where you got it from ?

They are like hens teeth to source.

Regards

Jerry

 

[morphix]

Interesting.

Can you give more details of where you got it from ?

They are like hens teeth to source.

Regards

Jerry

It came in the "Vitenso" branded kit (pre-laced into a wheel)..the motor has Vitenso engraved on it..they are specially made for RFTec in Austria (www.rftec.eu)

I paid around 300 euros for the kit (without any battery) plus 30 euros for shipping.. The only downside to this supplier is that all their instructions are in German and the sales people speak minimal English.. but apart from that, top quality kit and reliable supplier, fast delivery. They do the kit in a range of wheel sizes, except 16".

 

[jerrysimon]

I don't think its a Tongxin as the casing looks different. The Tongxin motors are virtually silent due to the use of steel roller bearing gears to drive it. They are made in China not Austria.

This is unique in that all other gear driven hub motors use nylon gears and hence are more noisy.

Regards

Jerry

 

[jerrysimon]

BTW if you are looking at 20" wheels or smaller you want to seriously consider suspension as small wheels on anything else other than smooth surfaces without suspension can get very uncomfortable. The Brompton falls mid way with rear suspension only, but of course folds really small. It is not cheap though.

An alternative cheaper one I have come across recently is a Downtube which does come with full suspension, though I have not ridden one so can't vouch for it.

Regards

Jerry