Re: Ebike Kit, Batteries And Trailer

[Joseph C.]

Hi all,

After some thought and deliberation I am going to immerse myself in
the world of E-Bikes. I would like to gauge your opinions on what I am
going to run with.

After talking to Cellman - this is the kit that I am thinking about running.

500 watt MAC motor kit.
48 volt 30 ah battery A123 Lithium.
Carry Freedom Y Frame Large Trailer.
Zarges Aluminium Box (800mm, 600mm, 410mm).
Torque Arm.

Cellman believes that this kit is capable of about 50 kph on the flat
with a range of 60k.

I have a couple of questions though.

What do you think the range would be at say 30 km per hour (20 mph roughly)?

Cellman told me that the throttle uses pulse width modulation
percentage - I looked it up and it isn't too difficult to understand -
but I would like to now how this works in real terms. Is it easy to
keep the bike at different speeds of say 15 kph, 25 kph, 35 kph etc
etc. Is a thumb throttle hard to keep pressed?

Do any of you have experience of trailers and do they affect
performance? I will be carrying at least 30 kgs of weight at any time
- the battery weighs 17 kg, the box weighs ten. I live in Ireland and
it can be quite windy here at times!

Finally, at 17 kgs - this battery isn't light - so I will be mounting
it in the trailer. Here is my question - the battery will be plug and
play but can I have a lead going into the trailer that is also plug
and play - allowing me to easily separate the trailer from the bike?

I look forward to hearing your replies,

Joseph.

 

[jag]

It sounds like you don't have much ebike experience. If at all possible try some ebikes before putting lots of money into buying a building a high end one yourself. Cell_man's recommendations are good, but with some experience everyone finds little things they would have done differently.

Personally I would split the battery pack, and mount 1/2 in the bike frame triangle, then ideally build the other half so it can go on the bike or in the trailer. The bike is much nicer to ride without the trailer. With the trailer I have to watch for bumps and obstacles much more carefully, and in practice have to go a lot slower.

I have a very similar setup (BMC motor approx same as MAC, batts in triangle) which I use with a trailer.
http://endless-sphere.com/forums/viewtopic.php?f=4&t=23518

 

[Drunkskunk]

Welcome to the forum. I agree with Jag, but as an example of how personal experiance changes perspective, I'd say split the battery in thirds, with 48V10Ah in the frame, and the rest in paniers on a back rack, when and if you need them. 10Ah is plenty for casual 10-15 mile rides.

The trailer will impact performance. there will be more rolling resistance, but the biggest factor is the wind resistance. If you can avoid using it, you'll increase your range.

 

[Joseph C.]

Splitting the battery is definitely something to consider Jag and
Drunkskunk. It is something that I hadn't given enough thought to.

However, Ireland isn't as liberal when it comes to E-bikes as America.
Having the trailer, apart from the fact that I will always be carrying
gear (laptop, charger, waterproofs, bike equipment etc, means that it
is much less conspicuous. So it is trade-off.

I want the large battery because I will sometimes be commuting 50 km or more.

You are correct though - I have very little experience of E-Bikes -
none actually! I am not sure if it is possible to take a test drive as
the only E-bikes for sale here have a paltry 25km per hour top speed
and I take it - won't be a good indicator. What I am trying to avoid
is buying a kit or battery that I will quickly outgrow. My uncle is an
electrician who probably will be getting a similar kit - so I will
have somebody technically-minded to assist me. As for the top speed -
50 kph - I won't be using that ordinarily - but I want to have that
option! I plan on going at a more leisurely 30 kph pace.

The roads where I live are quite good - all main roads/dual
carriageway. Does the trailer make the bike unstable in high winds?

 

[jag]

Splitting the battery is definitely something to consider Jag and Drunkskunk. It is something that I hadn't given enough thought to.

However, Ireland isn't as liberal when it comes to E-bikes as America. Having the trailer, apart from the fact that I will always be carrying gear (laptop, charger, waterproofs, bike equipment etc, means that it is much less conspicuous. So it is trade-off.

I want the large battery because I will sometimes be commuting 50 km or more.

You are correct though - I have very little experience of E-Bikes - none actually! I am not sure if it is possible to take a test drive as the only E-bikes for sale here have a paltry 25km per hour top speed and I take it - won't be a good indicator. What I am trying to avoid is buying a kit or battery that I will quickly outgrow. My uncle is an electrician who probably will be getting a similar kit - so I will have somebody technically-minded to assist me. As for the top speed - 50 kph - I won't be using that ordinarily - but I want to have that option! I plan on going at a more leisurely 30 kph pace.

The roads where I live are quite good - all main roads/dual carriageway. Does the trailer make the bike unstable in high winds?

The biggest cost by far is your 30Ah battery, but you can step up gradually:
1. Buy hub motor, controller and a 10 or 15Ah 48V battery.
2. Use this for a while to figure out with your actual riding conditions how far it takes you.
3. Then buy a second battery of the appropriate additional capacity (if needed)
Never overbuy.

In terms of stealth, I doubt many notice that my bike (above) is electric, whether I'm with or without the trailer. The batteries are in a triangle frame bag from a Canadian sports retailer (MEC) with their logo on, so people would just think I have some regular bike gear or food in there. Hub motor is not so visible because of brake disc on one side and freewheel and deraiuller on other.

I contemplated adding a hidden switch to switch between street legal and off-road power, but since the bike doesn't get noticed, I have had no problems in 2 years of daily riding.

I will make bigger panniers. This will both hide the rear hub more, and give me more capacity so I don;t need the trailer as often.

I ride up to 50-60km/h with the bike alone, but I only feel safe to go 20-30 with the trailer. The motor would take the trailer to near the same top speed. However the bike is suspended, but the trailer not and even a small bump at 50km/h would sent it in the air. I'm also sometimes forced to ride close to the side due to traffic or obstacles. Then I always have the fear that the trailer will catch a street sign post and get hung up on it. I've had some close calls.

 

[Lessss]

If your kit will do 32 kph and you are always going to have the trailer attached the extra resistance of the trailer will slow you down a fair bit, possibly close to 25 kph. Ireland doesn't have many BIG hills(over a short distance) so a 500W kit is likely going to be overkill unless you are in a very hilly area. 250W or 500W both will get to the same top speed, just a little slower. Of course having that extra wattage is better than not having it. The thing to consider is how much faster a 500W will drain the battery vs 250W/350W.

 

[izpirkt]

You could consider the possibility of a single wheel trailer, which would significantly decrease the wind resistance from the trailer shown, and decrease the danger of increased width. From my experience, if you discount wind, pulling a trailer is only really noticeable when accelerating or on hills. A powered trailer should not even be a factor in these situations. I'm actually working on a single wheeled trailer with the batteries and a hub motor on the trailer. I want to design something that is not going to permanently alter my bike, and will be easy to quickly remove. Also something that will lock up at the bike rack easily.

This forum is certainly the place to get some ideas and critique. Best of luck

 

[Joseph C.]

Thanks guys - these are some very helpful tips. I will do more
thinking and see about the cost element.

Having the ability to use the motor without the trailer is an
attractive idea as it give more options. I may consider reducing the
wattage and battery size too.

I would sort of hope to keep the trailer to a two-wheeler as I plan to
carry stuff that can be quite bulky.

What is your experience with range? At 30 kph or 20 miles per hour
what do you get out of your bikes? If I reduce the battery ah by one
third or one half - those that reduce the range in proportion?

Thanks for your support and your warm welcome.

 

[izpirkt]

A 50% reduction in the Ah capacity of a bank of batteries probably means more than a 50% reduction in range. From what I have gathered from this forum, the benefit of multiple batteries in parallel is that this not only increases the energy stored, but also the discharge capability. One of my DeWalt batteries can discharge 20Amps, but with two, I can discharge 40. If I am running just one battery, then I will come close to this amperage limit. With two, I am only at half the power possible. Batteries are less efficient the closer they are to their maximum discharge rate. Therefore one battery will not give 1/2 the range of two.

OK, that was a lot of information, so I'll try to summarize: less batteries will be strained easier, and lose power faster. If you are gentle with your power demands, any set of batteries will give increased range.

 

[Joseph C.]

Thanks Izpirkt,

Would it be much trouble to mount one 48 volt 20 ah battery on the
bike and then run another 48 volt 20 ah battery in the trailer in
parallel? Would I need two BMSs?

Yes, range is an issue for me as one long journey could be 80 kms or more.

 

[izpirkt]

I'm not sure how much trouble it would be to mount the batteries, but as far as the electrical connection for use, it is simple and straightforward. Simply split the lead to the controller from the batteries and have two parallel "input's" to the controller. Then you can hook up one or both batteries and the controller won't know the difference. With the batteries in parallel, the voltage will remain the same no matter how many batteries you have. The only caveat to this is the amperage draw that I mentioned earlier. The controller should not exceed a single battery discharge rate. This limits instantaneous power, but extends your range.

The BMS on a battery performs two functions. The first is for charging. The BMS reads the voltage of each cell in a battery pack and makes sure that none of the individual cells is overcharged. It can basically bleed voltage off of the full ones while the others are still being filled. The other job it does is while in use. It reads the voltage of the pack, and does not allow discharge past an unsafe voltage. This is called the LVC or low voltage cutoff. Normally the circuit is in each battery, and will turn it off when it reaches this limit.

Now, those two functions make it seem like you need a BMS for each battery. I think that this is normally the case, but some of the guys here are electrical geniuses, and have designed their own circuitry that preforms these functions separately. I don't entirely understand how this works. However, I have seen something called the "cycle analyst" which is a plug and play device that goes inline with the power circuit and can do amperage limiting and low voltage cutoff. This would stay with your bike, and not with the batteries, needing only one no matter how many packs you have. There are also some chargers that do cell balancing, eliminating the need on the battery pack. But again I don't know exactly how they work, so have avoided them.

Believe it or not, I have only really been perusing this forum for about a month, and have picked up all of this knowledge from reading what people have tried. I may never be an electronics whiz, but I think I can build at least one bike without letting out too much magic smoke.

 

[jag]

Thanks Izpirkt,

Would it be much trouble to mount one 48 volt 20 ah battery on the bike and then run another 48 volt 20 ah battery in the trailer in parallel? Would I need two BMSs?

Yes, range is an issue for me as one long journey could be 80 kms or more.

With my bike I average 15wh/km. Riding 25-30km/h and helping with pedalling I'm often using only about 10Wh/km. At full throttle (as much as possible in the city) and no pedalling I max out at close to 20Wh/km. Also with studded tires on both weels I using about to 20Wh. Now if yo build an efficient bike like mine you may thus only need one battery 15-20Ah at 48V (750-1000Wh) to go 60-80km.

If I have a long ride ahead of me I will just pay a little attention to conserving power. I have batteries with 250, 500 and 800Wh. For the past six month I've used only the smallest 250Wh and ride 20-25km with it. Personally I don't like heavy bikes and I'll rather pedal a bit than carry extra battery weight. And after all its a bike not a car. It's no catastrophy to run out of juice. Just have to pedal the last km. (Easy with the BMC/MAC geared motor, a bit more of a pain with my 9C direct drive (DD) motor I used before.)

 

[Joseph C.]

Now, those two functions make it seem like you need a BMS for each
battery. I think that this is normally the case, but some of the guys
here are electrical geniuses, and have designed their own circuitry
that preforms these functions separately. I don't entirely understand
how this works. However, I have seen something called the "cycle
analyst" which is a plug and play device that goes inline with the
power circuit and can do amperage limiting and low voltage cutoff.
This would stay with your bike, and not with the batteries, needing
only one no matter how many packs you have. There are also some
chargers that do cell balancing, eliminating the need on the battery
pack. But again I don't know exactly how they work, so have avoided
them.


Coincidently, I was on E-Bikeit.com reading about their cycle analyst
- and it seems to be a very good buy. €105 is a bit steep
though. However, if it saves on the price of BMS kits - it could be a
good investment. Plus it can set a speed limit. A good back-lit
computer could set me back €60 anyway!

However, I doubt that would be as good as a BMS system - which judging
from what you have said - monitors individual battery cells.

Hmmmm, decisions, decisions!

 

[Drunkskunk]

I highly recomend a Cycle analyst. And get a controller that allows you to use the direct plug in model as well, there is more functionality that way.

You need a BMS or something similar during charging. Lithium cells must be balanced during the charge. Some chargers will do balancing, especialy those ment for RC applications. Since you're planning to use A123 cells, The Cycle Analyst can handle the LVC (low voltage cut off) and let you moniter for other signs of trouble.

I would stick with the motor you chose originaly, especialy for hauling things. There is no advantage to a smaller motor. Going 20kmh uses the same amount of power regardless of the size of motor, but the bigger motor will handle heavier loads better, with more torque, and less chance of overheating.

No problem running part of the battery on the traler parralleled with the battery on the bike. Since it's going to be made of A123, its already going to be a lot of parrelleled batteries

 

[Joseph C.]

Drunkskunk wrote:
I highly recomend a Cycle analyst. And get a controller that allows
you to use the direct plug in model as well, there is more
functionality that way.

You need a BMS or something similar during charging. Lithium cells
must be balanced during the charge. Some chargers will do balancing,
especialy those ment for RC applications. Since you're planning to use
A123 cells, The Cycle Analyst can handle the LVC (low voltage cut off)
and let you moniter for other signs of trouble.

I would stick with the motor you chose originaly, especialy for
hauling things. There is no advantage to a smaller motor. Going 20kmh
uses the same amount of power regardless of the size of motor, but the
bigger motor will handle heavier loads better, with more torque, and
less chance of overheating.

No problem running part of the battery on the traler parralleled with
the battery on the bike. Since it's going to be made of A123, its
already going to be a lot of parrelleled batteries


I am going to follow your advice and the thoughts the other forum
members expressed. The plan is to get the trailer parts first and then
the ebike and battery kit.

I will be start off with a smaller battery and then I'll add to it as
I go along.

I have ordered the Zarges aluminium box today - I will order the
trailer tomorrow. When I get these next week I will see how the bike
handles etc. before sending off for the bike kit.

I will go with the 500 watt rear MAC motor and a 48 volt 10ah battery
set up with a cycle analyst. I'll place the battery in a frame bag.

The MEC website doesn't really like shipping outside of Canada - and
the postage/duties are outrageously expensive (going by their website)
- so I will try and source another site for a frame bag. Perhaps you
have suggestions?

 

[Joseph C.]

Thanks guys for all of your advice and support. I am indebted to the
knowledge that you have accumulated on the forum.

I ordered the rear 500 watt geared motor kit from Cell_man early this
week along with a 16S5P battery. My next step will be to order the
Cycle Analyst.

I purchased a frame bag from Falconev and have been using it for
several weeks now, although it is a shade too small for my large
bicycle frame.

The Carry Freedom trailer and Zarges box have been working a treat and
gives me all the space I need for carrying items. I have clocked over
300 kilometres (187 miles) in just over four weeks already and I feel
fantastic as a result. The first 30 miles or so were hell with the
Brooks's saddle that I confiscated from my mother's old bicycle but it
is getting more and more comfortable.

It took me nearly 150 miles to up my cadence and lower the gearing but
it was a lesson well learned and my legs are no longer so tired from
the build up of lactic acid.

Surprisingly, the trailer (which normally weighs over 20 kilos - all
inclusive) hasn't really noticeably affected my speed as I manage over
22 kilometres per hour (14 miles) on my rigid mountain bike with
knobbly tyres over journeys of 17 and 22 kilometres (11 and 14 miles)
respectively.

This March has been very mild in Ireland but I may purchase the Veltop
canopy for protection against the elements.

I can't wait for the kit and battery to arrive - it should increase my
speed considerably, especially on the hilly sections and I imagine
that there will be a serious aerodynamic drag with the Veltop canopy
will be helped no end by the electrical assist.

Kind Regards,

Joseph.

 

[Joseph C.]

UPDATE: On the kit. I will probably edit this in the morning as I will
undoubtedly have made a fair amount of errors from fatigue.

I finally obtained an ebike on after receiving Cellman's kit
yesterday. After a bit of messing around with my uncle, who assisted
me in putting it together and will probably purchase a similar set-up
after test-riding it, we decided that a free-wheel remover tool cannot
be substituted so we went to the local bike shop for assistance
removing the freewheel 7-speed cogs from the old wheel.

With the freewheel in one hand and the wheel in the other we headed
back and proceeded to meander our way through the installation. We
installed the motor into the rear wheel and then I proceeded to blow
up the wheel. My pump is a highly efficient double action with
manometer. But after pumping it for three minutes solid - the tyre
still remained flat. I thought it may be the pump so I tried another
one.

After nearly one hour scratching our heads, the wheel was perfect
previous to this, I removed it only to discover that the tube was
punctured. I had been far too eager with the tyre lever. Eight minutes
later with a new tube fitted, the wheel was on.

Then began the attachment of the brakes - we started off with the rear
first. After adjusting it and apparently getting it correct - I tried
to lift the rear wheel and peddle to make sure it wasn't fouling.
After three or four attempts, we realised that I had to tighten the
nuts. I wanted to tighten them at the very end but forgot they were
loose.

Figuring out how the brake mechanism works was quite fun but time
consuming. I do understand now though.

So we wired up all of the things. I kept all of my gears, I moved the
e-brakes over to accommodate the throttle. It is quite a strange
looking set-up. I hacked a little bit off the small grip and the
half-throttle fitted nicely.

There is only only one connector on Cellman's set-up for an ebrake (I
assume all are the same) so you either have to pick and choose which
one or splice the two together with a connector or some other
preferred method. As we didn't have a connector we choose one. Here is
a tip - which ever side the throttle is on - connect the ebrake from
the other side to the controller. In my case the throttle is on the
right side and the ebrake that is connected is on the left. That way
if I hit the right-brake first - I naturally have to take my hand off
the throttle. Whereas if I hit the left brake - the motor will cut
out.

We installed the controller too far back on the rear rack/carrier -
which meant the connectors are awkward to fit in some cases and
interfere with the brakes (they are cantilevers not discs).

I installed the cycle analyst but I have yet to install the speedo and
look at the manual to change the settings. Although I had a look at
the instructions before I put it on several days ago.

The battery was already charged from Cellman but a word of warning - I
was very fortunate. The battery may not be set to the correct voltage
depending upon where you are from. I was lucky that it was set to the
correct voltage - I was pre-warned by Cellman but I couldn't see the
switch that he referred to and tried it anyway - I was lucky. It is a
red switch underneath the grill - to the left of the on/off switch and
the power inlet. It will either say 230 or 110 volts. I assume you
have to press it with a small screwdriver to change the setting if it
is unsuitable.

After wiring everything up and securing it with cable ties - I took it
for a short test run for a couple of metres of so. I ripped the cover
off the front sprocket as I was a bit confused. The front gear changer
is a second-hand replacement after I tried to fix the gears - I had to
admit defeat and get the local bike shop to fix them.

The damage from my gear-setting/fixing attempt was a broken grip-shift
that had to replaced several months ago by people who are used to
these things. So now I have two gear index systems - a SRAM and a
Shimano - which gets really confusing as they both turn in opposite
directions to change the gears and the writing has long since rubbed
off both of them.

So the front chainset cover is now missing two screws after the first
test run - the index pushes it over too far - but that is the problem
with using a SRAM system that isn't designed for the bike.

I was disappointed with the performance as I was expecting something
much faster and the motor gave a heavy clunking sound as it maxed out.
After watching my uncle's test ride and trying it again for a short
second spin. A thought occurred to me that the Cycle Analyst was
limiting the speed and cutting out the motor.

So I tried another run with the analyst disconnected this time. The
difference in speed was discernible straight-away. The top speed was
immense - I would imagine it would be even better in daylight. It was
after 11pm and it was moderately raining - plus the lights are in need
of being charged - so the visceral experience was a bit sullied by
this. It feels like the bike is going at least 35 miles an hour. I
have never experienced the weird sensation of pedalling air quite like
this. I would seriously question the sanity of people going much
faster than this on a bicycle on public roads. At this speed you are
talking light-motorcycle.

Here are my observations on the throttle using a twist-grip or a
half-twist in my case could be problematic as you could accidentally
hit when you are mounting/dismounting the bike or walking it etc. This
is something that should be considered. I believe a thumb-throttle
would completely negate this. The question is would it feel as natural
or as comfortable?

I have had a bicycle trailer, A Carry Freedom Y-Frame Large, for the
past three months. They are amazing - I cycle over 17 kilometres (11.2
miles) in just over 50 minutes on average with something 20 kilos in
weight on it with some short mild to steep hills along the way. I
recommend them to anyone who will listen.

I have a Zarges 150-something litre aluminium box that I have bolted
to the trailer and I will be advertising my business on it. It is
great! I can lock up the trailer - use my flexible combination lock to
connect the trailer to the bike and use a motorcycle lock to secure my
bike - it gives very good piece of mind. And I can carry anything. If
I wanted to carry lengths of timber I could get an extra long
extension handle.

The hitch for the trailer attaches to the rear bicycle axle. The
problem with the motor-kit, and any electric motor kit irrespective of
wattage, is that hitch hole will be too small for the 14mm axle. So it
will have to be bored and made bigger. I will either find someone that
has a 14mm bit or will purchase one. I may just ask the designer of
the bike to make a custom one for me failing the other two options.

I also bought a torque arm from Cellman. Here is the problem though if
you have a trailer like mine - unless you want to go and pull apart
all the connectors on the motor lead you will be limited to using the
chain/sprocket side. This isn't a problem with the trailer I have as
it will work on both sides of the axle. It may be a problem for
others.

Secondly, obviously the same restrictions apply to mounting the torque
arm as above. So ultimately you may not have enough room to use both a
torque arm and a hitch on the same side of the axle - which looks
likely in my case. Therefore, it will be a compromise.

Lastly, as my father - who arrived later - pointed out to me - I had
the washers on incorrectly on the wheel. I believe that you should
have one on each side of the drop-outs. I stupidly put both washers on
one side of the drop-outs. He advised me that it would splay out the
drop-outs. I assume that he is correct.

I will therefore have to take off the wheel again and remove all the
cable ties and disconnect stuff from the controller that I have
awkwardly placed too far back on the carrier/rack.

Perhaps people in the know could tell me if is the case. And maybe
they could offer some perspective on how serious this issue is. I want
to use the bike tomorrow and make the changes in a couple of days
time. Monday or Tuesday perhaps.

Finally, I noticed that the power cables from the battery to the
controller had a separate red connector. When this connector is
removed the voltage drops. It seems to be a limiter. The bike - also
seems to lose the ability to start instantaneously. Although I only
observed this when I had the bike outside and was testing the motor at
the initial stages.

The bike, my 12 year old 21-speed Giant Boulder 500 with a 21.5 inch
frame and 26 inch wheels. I have had it since I used it to travel to
under-age football training (Gaelic) so it has served me well. It is a
rigid but it does have a Brooks saddle with springs confiscated from
my mother's unused bicycle.

I purchased the frame bag to hold the battery from Falcon EV.

The battery is the 16series 5phase A123. 54.8 volts nominal (57.6
volts charged) 630 watt hours triangle pack.

The charger: 57.8 volt 6amp.

The controller is the 9fet Infineon. With plugin Cycle Analyst cable.
I forget the Controller number. 3077.

The motor is the Mac 500 watt rear geared - it seems to me to be an
absolute beast.

The display: Cycle Analyst with magnetic sensor - yet to be connected
and calibrated.

The bike now weighs 28 kilos. The battery weighs about 6.5 kg and the
motor and wheel come to 5.1kg. This may seem heavy but to me if feels
about the same as pulling an empty trailer. You are talking about an
average speed of 18 to 19 kilometres an hour - 15 miles an hour over a
moderately mixed gradient.

I tested it out and it feels nice and light in the front middle
sprocket and rear smallest sprocket - although you may want to put it
in a lower gear at the back and wait until you build up speed. It is
for this reason that I have persisted with keeping all my gears. If I
run out of range - the bike will be easy to peddle up hills etc.

Once you know how to use gears properly and keep everything feeling
fairly light - it won't present any hassle cycling it. The geared
motor offers no discernible resistance. and the weight is nice and
centred. The bike stand actually has improved with the added weight
and the chances of it falling over are less likely. Because of the
awkward layout of the rear derailleur, and rear brake cables, - I had
to abandon mounting a central double kickstand and settle for a
rear-chainstay frame stand instead.

 

[Joseph C.]

A problem has developed with the throttle today. Sometimes it won't
work and the motor tends to be quick jerky. It keeps cutting in and
out. It seems to need much more throttle as well to get up to a decent
pace. I have tried it with and without the cycle analyst but it
remains the same.

Do you think the problem is a loose connection or is there something
wrong with the Hall Sensors? What should I do?

Any help would be much appreciated.

 

[Joseph C.]

Does anybody have any idea at what voltage the BMS hits the LVC? I
still haven't configured the Cycle Analyst properly and twice I have
been caught out.

The battery is 16 series 11.5amp A123 (52.8 volts nominal). It appears
to cut out at 48 volts give or take.

Any help would be much appreciated.

 

[TonyReynolds]

I would love to see some follow-ups on this excellent thread as well, since this is about the same kit that I'm thinking of purchasing from cell_man.

Great job, Joseph, and best of luck getting it sorted out. (I'm no help as i'm where you were 3 months ago...)

Tony
Seattle

 

[Joseph C.]

Thanks Tony, I would recommend it so far. I have 510 kilometres done
in the past five weeks with 11 cycles on the battery. I average about
20 to 25 kph but I always haul a trailer with a large aluminium box,
with several kilo in it, so my efficiency wouldn't be anywhere near as
good as someone with just a sole bike. Plus Ireland is quite windy and
wet. Going into the wind and rain seems to use twice as much amp hours
as riding with it.

If I can get the correct shunt value for the Cycle Analyst - I would
be away with it.

 

[amberwolf]

Does anybody have any idea at what voltage the BMS hits the LVC? I still haven't configured the Cycle Analyst properly and twice I have been caught out.

The battery is 16 series 11.5amp A123 (52.8 volts nominal). It appears to cut out at 48 volts give or take.

Any help would be much appreciated.

Well, the easy way to figure it out is to check the Vmin on the CA, and whatever that is is the lowest voltage things were at during a ride.

If it cut out during that ride, then that voltage or higher is the cutout.


However, the voltage is not the best way to track it; the best is to test ride your pack on a hard ride, until cutoff, and then note down that amount of Ah (or Wh, or both), and then keep an eye on those readings each time you ride. When you reach half of that value, it's time to turn around and go back, or ensure you have a charging spot before you run out.

If I can get the correct shunt value for the Cycle Analyst - I would be away with it.

There are some ways posted in various threads on how to find the controller's shunt value, if your CA is the DP version. There are also various threads about different controllers that state their shunt values, so if yours is one of those, or a similar type and rating, you could use one of those values, and then adjust up and down until it's nailed in, over several rides vs charges.

If it is the SA version, it should have come programmed with the right value already, whcih is around 1.3mOhm.

 

[Joseph C.]

amberwolf wrote:
There are some ways posted in various threads on how to find the
controller's shunt value, if your CA is the DP version. There are also
various threads about different controllers that state their shunt
values, so if yours is one of those, or a similar type and rating, you
could use one of those values, and then adjust up and down until it's
nailed in, over several rides vs charges.

If it is the SA version, it should have come programmed with the right
value already, whcih is around 1.3mOhm.


I have tried searching - so far to no avail. Its a 9fet 30 amp
Infineon 3077. The best info I found was from Justin Le but it isn't
very specific - a range between 3.5 and 5 mOhm - I assume a 9 fet
value would be between those for a 6 fet and 12 fet. It is a direct
plugin.

The infineon controllers all seem to have unnecessarily high shunt
resistances. On the ones we carry, the 6 FET boards are usually
between 5 to 6 mOhm, while the 12 FET boards are usually between 2.5
to 3.5 mOhm. So your value of 3.5488 sounds perfectly normal.

Most other controller models have shunts between 1 to 2 mOhm which
makes more sense. With the infineon's It's silly because if you use
good fets, you will loose about as much heat through the shunt as you
do through the transistors.

-Justin


Thanks also for you advice on checking the min voltage. Self-directed

 

[amberwolf]

I have tried searching - so far to no avail. Its a 9fet 30 amp Infineon 3077. The best info I found was from Justin Le but it isn't very specific - a range between 3.5 and 5 mOhm - I assume a 9 fet value would be between those for a 6 fet and 12 fet.

Probably. If you were to take the average value of the data in your quoted info above, it would come out to 4.25mOhm; perhaps start there and then see how closely that conforms to the expected pack values?

Though, really, other than for pure accuracy's sake, or for setting up current or watt limiting via the CA, it does not matter if the shunt is correct or not, only that it is consistent. If you are really only using it for counting the Ah or Wh for capacity monitoring, so you know how much range you have, it doesn't matter if the numbers are off by a factor of 10 or 100, even.

You'd just note down whatever number you do come up with when its' run down from a full charge to cutoff, and then use that as your capacity.

Thanks also for you advice on checking the min voltage. Self-directed

Well, that's how I had to figure it out on mine. Works well enough.
http://endless-sphere.com/forums/viewtopic.php?p=394756#p394756

 

[Joseph C.]

First 1000 kilometre update.

Well I have covered my first 1,000 kilometres roughly about three or four weeks ago with about 36 cycles on the battery. A conservative estimate of the electricity costs is around €2. Not too bad at all.

Observations: The kit is very good. It uses roughly 15 watt hours per kilometre at about 30 kph with the trailer attached this is usually with some headwind. Which gives a theoretical range of about 40 kilometres. Having the seat set at the correct height is very important for pedalling efficiency and I could see an immediate improvement to the efficiency figures when it was set correctly.

The throttle sometimes doesn't work but a quick jiggle and it is fixed. I really should do something about that...I guess I'm waiting for it to fully stop working. :wink:

The trailer is holding up well but the fibreglass pole of the flag started to wear away due to friction with the trailer box. Some black insulation tape fixed that though.

Some might be wondering how much having an ebike costs. Here is my breakdown:

Total cost for the ebike kit €818
Cycle Analyst €101
Local Bike Shop Repairs To Bicycle €75
Y-Frame Large Trailer €250
Zarges Aluminium Box €248
Bicycle Accessories: lights, kick stand, carrier, overshoes, locks, tyre liners etc. €188

Total Spend €1,680

I have travelled over 1,500 kilometres on my bike so far, 1,000 with the ebike and 500 without. Which works out at €1.12 per kilometre. If I had a car it would probably cost me a minimum of €2 per km with all expenses included.

In terms of the battery alone, at about €470, the total distance works out at 31 cent per kilometre or 47 cents if you just go by the 1,000 km. I still have a fair bit to go before I rival the cost per kilometre of the local bus which is currently at 17 per kilometre. Another 2,000 kilometres to go.

Upgrades/Additions

I will probably need some additional purchases. Schwable Marathon Winter tyres will probably be required for the harsh winters we now seem to be getting annually. A Veltop cover is also on the list of things to get to stop the torrents of rain as well as a Goretex trousers. Finally, a lights upgrade is badly needed. Magicshine lights will be next on the list.

All told these extras will probably be an extra €650 and they are all needed for all-year round cycling.

That's leaves a two other things that will be options. An extra battery mounted in the trailer and a Thudbuster seat post as the bike is rigid. Perhaps another €1,000 all told.

That will drive the total up to €3,330. So I will need to cycle 20,000 kilometres to beat the bus for cost efficiency. Four years give or take.