warmrain

I have lithium cells in my laptop more than 11yr old which are working just fine albeit the wattHour capacity has declined.

I don't know the specifications of the Yamaha bike but the battery is not the main problem as it is clearly capable of powering the current motor (albeit total capacity might have reduced). I suspect the maximum torque from the motor is low and inadequate, especially on this old model of e-bike and hence the problem with hills. The point about not adding more weight is also relevant as it may not give you the best weight-vs-performance ratio. I am sorry to hear of your health problems, but you might be better off selling off your old bike to someone who lives in a flat city/town and use the proceeds to supplement purchase of a new bike with motor capable of delivering at least 85nM max torque? [With a good range of gears.]

Hi mm1, I notice that CambridgeCycleCo.co.uk has stock of 1x Gazelle Orange C7+ Low Step-thru with XS frame size of 46cm at £2199. Need to get in quick if interested as they seem to be out of stock in everything else.

You are welcome. Let us know how you get on.

Hello mm1, the shop I'm thinking of is in Navenby village just south of Lincoln and is called PedalElectricCycles. Need to phone first [01522-255760] to fix an appt because of Covid, and also best to enquire whether he has the specific model(s) you are hoping to try available in the shop. He has a few more in a warehouse which he could bring round to the shop but stock may have diminished somewhat because I have just bought one off him . Navenby has a nice sharp hill just yards from the shop and some quiet backroads behind -- so good location to test out the bikes.

Gazelle are still selling in the UK and if you type "gazelle bikes cambridge" into Google you will see 3 dealers come up near you. I believe their models 'Ami', 'Paris', 'Orange' and 'Grenoble' all come with an option of step thru in XS (extra-small) size - 44cm frame - 'suitable for person height of 1.55-1.65m' so should suit you. The first is a Shimano crank drive and the latter three Bosch. I have a very helpful Gazelle dealer near me in Lincolnshire who has lots of Gazelles to try, but that might be too far away for you(?).

Hello, look at this thread. http://www.pedelecs.co.uk/forum/threads/kalkhoff-panasonic-charger.32259/ Good luck.

I see that the subject of this discussion was/is "Cheating". Not how an electric bike should be described or what legal terminology is adopted by relevant authorities. "Cheating" is something purely intrinsic to, and in the mind of he/she who says 'it is cheating'. It arises because either (a) they feel they are in competition, or (b) they feel there is something they are entitled to which they don't have access. The traffic light dragster who feels you are cheating because your stock looking Ford Fiesta has a modified supercharged engine and you outdrag him in his *really* stock Ford Fiesta has a self made problem because he has set himself up in competition with you ... and also feels he should be entitled to a supercharged motor as well. ....(a), and (b). The person who feels rich heiresses are "cheating"/ "have cheated" because they-just-happened-to-be-the-daughter of a rich family and didn't work for it are agonising because of their indignant sense of entitlement ... and also setting themselves in comparison & competition. Even though objectively they themselves may be both healthy and and have enough to eat/live without hardship. [Marxists may beg to differ]. The person who invented the aeroplane wasn't "cheating". He was just solving a technical problem. When electric bikes are (almost) the same price as non-electric bikes, there will be no chance for a sense of witheld entitlement and it will be simply an engineering advance that gives you a choice of having more exercise or less exercise. Those who still mistakenly feel that the world is competing against them will turn their attention to having a snazzier paint job on 'their superior' electric bike. It is a technical / engineering advance which can also sometimes solve a human medical problem. 'Cheating' is simply a problem within the own psyche of he who calls out "you cheat!" at the moment. Don't worry about it.

Thanks for the suggestion. I guess its a trade off whether to lug it along as my new battery is substantially larger capacity wise and should cover most circumstances - if it lives up to its stated capacity rating ... delivered from Germany but in small print says 'Made in China'. Some good stuff is made in China -- all those hub motors used by various UK bike manufacturers are made in China I believe. I couldn't bring myself to pay £600+ to 50Cycles, and this is less than half of that.

OK, an update. SUCCESS !! I have managed to get my charger working! Some details of voltage testing of the charger WITHOUT being connected to the battery: After rest overnight without being plugged in -- zero volts across any pair of terminals. On plugging into the mains, intially zero, then after a few seconds I hear a very very faint click followed by a jump up in voltages across some terminals BUT in REVERSE polarity (of expected). Between B & E = 10.9v with 'E' positive. Between D & E = 12.3v with 'E' positive. Between B & D (the main charger output pins for battery) = 0 v. On then unplugging the charger from mains, both these voltages decay slowly over several hours. [This suggests to me they are residual voltages on some sort of internal capacitor.] I then opened up the charger. Rather fiddly job as it is held together by 'security Torx' screws which have a raised 'pip' in the centre. I needed to go source a corresponding 'security Torx' screwdriver (of T10 size) which has a hole in the centre of the business tip. I then lifted out the charging terminal from the charger and plugged it firmly into my NEW partly discharged battery [CAUTION!: need to get the pins correctly oriented!] and Eureka!! it started charging the battery! The pins on my charger are not burnt or corroded and the pins on my battery are new. I believe the Kalkhoff charger simply has a design flaw in its construction which means that batteries which sit on it don't get the pins inserted deeply enough. I had noticed incidentally that my new larger bodied higher capacity battery did not sit as stably on the charger, albeit the pins still *seemed* to insert OK. I have a suspicion that TILLSON's problem with intermittent functioning of his charger may be due to the same problem. I now have a new project in front of me which is to lead an extension wire out of the charger to a 'flying plug-in' connector for the battery. Now, some voltage measurements with the battery operating with the charger: Battery OFF the charger (initial state) :-- pins A-D = 25.8v [battery output pins] pins B-D = 25.8v [battery charging pins] pins B-E = 25.3v [? battery monitoring/communication pins?] Battery ON the charger's corresponding pins (charger then switched ON at mains). pins B-D = 26.0v [ie charger outputting voltage 0.2v above battery initial] pins B-E = 23.0v [the ?'monitoring' pin has 3v less than main pair.] pins D-E confirm 3v difference (with D neg, E 'pos'). At end-of-charging after several hours (charger power transistors gone cold, battery LEDs all gone dark) and battery still connected: pins B-D = 28.9v pins B-E = 28.3v pins D-E = 0.62v [Note decrease in difference voltage.] AND the BONUS. I had thought my old Kalkhoff battery was dead. No LEDs lit on pressing test button, voltage across all 'main' pins A-D, B-D was only 2.4v (two point four); across 'monitoring' pins B-E also 2.4v; across 'battery meter' pins A-C 2.2v. No response putting it into the Panasonic/Kalkhoff charger. For a laugh, I plugged it into the detached pin block of the charger .... and it started charging! I now have an old "Dead" battery charged to 29.2v albeit I suspect its overall capacity is low despite the appropriate voltage. I will try it in due course to see. I remain curious as to what and how the 'monitoring' pin 'E' works on charger and battery. I had thought after finding 10.9 / 12.1 v reverse voltage on that charger pin that pin E was used by the charger to detect a minimum battery voltage of at least > 12v before deciding to operate (this perhaps being related to the 'unsafe' minimum voltage below which one should not charge a Li-Ion cell), but clearly it worked even with a battery voltage of 2.4v . So, what is its function and how is it connected into the circuit(s)? Thanks to all who have helped in this investigation so far!

Thanks for that suggestion. Firstly, to eliminate misunderstanding (because FLECC has referred to the pins in a different numbering sequence) I have put up below a new photo with pins on my old battery & charger numbered A to E. Pin A on the battery connects into + (POS) for the motor on the BIKE but has no connection on the charger. Pin B is also +(POS) and connects to the charger. Pin C is NEG and (I believe) connects to the battery meter on the bike but has no function on the charger because it connects to a charger pin which is a dummy (not connected internally to anything but just used to help register/orientate the battery onto the charger). Pin D is 'common' NEG for both connection to bike and to charger. I have never before quite figured out what Pin E does on battery or charger (it has no connection on the bike) but I have found generally that the voltage on the battery between Pin E (NEG) and either of the two positive pins will mirror the same voltage as found between the two main 'output' pins, A & D. Are you suggesting therefore that the charger has to see a suitable voltage from Pin E of the battery before it will start (and continue) charging? [...And what limits will that voltage have to stay within ......]

Thanks very much indeed for that test & info. I take it there is no voltage when plugged into the mains across ANY pair of pins (when the battery is not connected). That still leaves me with the puzzle of WHAT makes the charger want to start delivering a charge. I think I might try opening the charger to check all the connectors before also speculating whether my new battery is in some way incompatible with the charger ... unless someone with more electronic knowledge understands how this Panasonic charger works...?

Hmm... Thanks.

Thanks. Will do.

Thanks FLECC. Some useful information there. However I would like to be certain that my charger is faulty (or unfixable) before I throw it away. Do you or anyone else know whether this or similar Kalkhoff/Panasonic '29.3v' chargers should show 29v at the charging terminals when plugged into the mains, without the battery plugged into the charger? I would also love to know how & whether the battery communicates/influences the charger in some way BEFORE the charger will start working. Posters NRG & 10mph had some discussion about this charger/battery in the past but the posting did not give me the info I need. I wonder if they still have their chargers?....

Hello all, I am trying to determine whether a (Kalkhoff)/Panasonic "25v" charger I have is working properly. It is a Panasonic NKJ039 model; stated output "29.3v 1.8A" charger which came with an old Kalkhoff Tasman bike with 25v panasonic motor. I bought a replacement battery last week and it will not charge when put in the charger -- battery has 4 (of 5) lights showing on self test, and voltage between output terminals of battery is now down to 25.8v (from initial 27.4) after some usage on the bike. Picture below is of the pins on the charger. I believe pin labelled '2' is positive output, '3' is a dummy, '4' is neg, and '5' is a sensing/battery monitoring pin of some sort. My question is: (a) What does pin '5' sense? What voltage perhaps does it need to sense? (b) Should a battery reading 25.8v start charging when inserted? (Nothing happens at present). © Should there be a voltage between '2' and '4' when the charger is plugged into the mains but battery not plugged into the charger? Essentially I am trying to figure out what normally triggers (and stops) the charger to deliver a charge; or is it just broken? (...and can it be fixed.) My previous battery could be charged up from various intermediate states of discharge. Thanks.

This question can be answered with some basic physics. There are two situations - (1) travelling on the flat; and (2) going up any kind of slope however slight. Calculate/convert everything to JOULES (a measure of total energy) and WATTS (a measure of how much energy - joules - is being consumed or needs to be supplied per second). (1) On the flat, each time you accelerate from zero or increase your speed you have to add Kinetic energy. Thereafter, some energy is required to overcome the rolling resistance of your bike/tyres and wind resistance but these are relatively smaller compared to the change in Kinetic energy. Unfortunately when you slow down, 99% of the kinetic energy is wasted/lost by conversion to heat in your brake linings. 1% may be 'recovered/usefully used' for overcoming air & tyre resistance during the de-acceleration period. (2) Going up a hill/slope, you need to supply enough enough energy equal to your increase in Potential Energy relative to your starting height on the earth's surface. Unfortunately, when you go downhill, even if you freewheel rather than brake intermittently, you are still unlikely to convert more than a small proportion (<50%) of your accumulated Potential energy to Kinetic energy because of increased wind resistance etc during the speedy descent. So, to actual numbers. (1) Situation on the flat and level. Kinetic Energy (in Joules) = mass (kg) x speed (metres/sec). 15mph = 6.7 metres/sec. An 80kg man with 20kg bike accelerating from zero up to 15mph would need to supply 670 joules (100x6.7) each time. Adding 5kg of milk, you would need 703.5 joules each time -- an increase of 5% in energy. Remember, everytime you slow down again, all that is lost. With a 31kg bike and 5kg milk, the energy needed is 777.2 joules -- an increase of 16%. https://www.chem.wisc.edu/deptfiles/genchem/netorial/modules/thermodynamics/energy/energy2.htm (2) Going up a hill. Potential Energy = mxgxh (where m=mass in kg, g=gravitational acceleration, h=height in metres). g=9.8 m/sec/sec. An 80kg man with 20kg bike going up a 1:10 hill at 5mph ascends approx 0.22 metres/sec (simple trig.) -- therefore energy needed is 215.6 joules per second (100x9.8x0.22). 1 joule/sec = 1 watt. An averagely fit adult can sustain about 50 - 150 watts of work consistently, so you can see that to produce over 200 watts to go up a gentle hill is quite an effort. If the total weight is increased to 116kg (80+31+5), you need to sustain 250 watts -- another increase of 16%, but much more effort over accelerating on the level where one might normally take, say, 5 sec to get up to 15mph and requiring only 140 watts (703 / 5) during that 5 second period. Going uphill requires almost 80% more effort (250 / 140) - whether supplied by man or man plus battery/motor - than speeding up and slowing down on the level; ... and for a relatively gentle hill at that. (3) As regards battery range. The average 'standard original battery' is of about 300 Wh capacity. 1 Wh = 3600 joules. So 1,080,000 joules. But conversion inefficiency through the motor may optimistically only deliver no more than 75% of this -- so 810,000 joules available. Potential energy required for lifting 100kg up a 50m hill is 49,000 joules. Empirical estimates of energy consumption for air resistance etc at 15mph constant sped on the level is about 100-120 Watts -- ie. 120 joules/sec -- or about 432,000 joules per hour, not including de-accelerations/re-accelerations. Depending on how much is supplied by you and how much is set to be supplied by your bike motor (50%?) -- one can work out how long/far you can theoretically go. In practice, your own bodyweight has by far the most effect proportionately in most situations, but especially in hilly areas! WR

Hello, I have a Panasonic 24v crank drive system on a Kalkhoff Tasman bike. I cannot see any magnets on the rear wheel. Does anyone know how the motor control detects the speed of the bike and where is the road speed sensor located? Does it just measure the crank speed instead and estimate the road speed based on what it thinks what hub gear ratio is engaged? -- but then, how will it know what gear ratio is engaged? I am trying to understand how its software manages to control the power delivery curve. Thanks.

Incidentally, Oriteroom, I did successfully bid for these batteries(!) but had to return them because they both had some kind of internal fault as the main output connections (indentified as per Flecc's documentation and also verified on my old battery) only had 2.9 to 3.0v despite being apparently charged up with 5 lit LEDs. They also didn't look quite as new as described... Just a heads up to anyone else to think carefully, in case these particular batteries above get relisted!

Good point Flecc regarding the 20.8aH battery.! Doing the best estimation I can, measuring the likely projection from the one fixed point I have which is the connector slot and stated battery dimensions I reckon it may project at least 6cm, which is at best very very close to hitting the R hand (offside) crank -- within a millimetre or so. Unfortunately I can't be sure without having a physical example to try out and I wouldn't want to get one without being sure. Bit of a catch22 situation! It would have been better if they had redesigned the larger case to be taller (with the lock in the same place) instead of being fatter

Thanks to Oriteroom for pointing me towards ebay. Has anyone tried or used this replacement below (or any other batteries from that seller) for any length of time, and are they any good? Made in China and supposedly constructed with 'Samsung cells'. http://www.ebay.co.uk/itm/24v-25-2v-20-8ah-electric-bicycle-lithium-ion-battery-sliver-new-SAMSUNG-cell-/222011627958?hash=item33b0ec99b6:g:zU4AAOSwOVpXa1jE

Many thanks for the information on the Panasonic system and batteries Flecc. Very useful. I think perhaps before I do anything else I should take it through a couple of full "reconditioning" cycles first and see how much it improves matters. Incidentally, what voltage do you think one should be getting (measured) at the battery if it is truly discharged to its safe limit and not just the BMS/controller monitoring system getting out of calibration? Also, I suppose if there were just one bad cell in the battery it might pull down the voltage when on high load and trigger the low battery warning light?

My apologies for not making it clear. The bike has what I presume to be a Panasonic crank motor running at a nominal 24v. The battery actually has 5 terminals. One is marked (+) and one marked © with the others being negative. Remeasuring now with a reasonable quality digital multimeter, the reading (after full charge and standing for 24hr) the reading of either (+) or © terminal against either of the 'outer' negative terminals gives 28.6v but if measured against the 'middle' negative terminal gives 26.1v . Sorry for the initial confusion and also thanks for the reference to Insat Services. I still wonder if I can renew it myself though and would appreciate any other advice.

Hello all, My wife bought a secondhand Kalkhoff Tasman electric bike which was "new" in 2008. After a small service on the mechanicals it works well but I suspect the "10aH Li-ion Mn" battery has lost substantial capacity because it registers a blinking low battery light (from full) after just a mile or so in moderately hilly terrain. At that point (low blinking light) the resting voltage across the two measurable pairs of terminals on the removed battery measures 25.5v and 28v. Immediately following a full recharge to charger switch off, the voltages are 26.2v and 28.8v. After then standing for 24hr, the corresponding resting voltages are 28.6v and 28.6v. My queries are: 1/ I presume one of those voltages is the "reference" voltage set after charging which the BMS/contoller uses to decide how discharged the battery is. -- Is this correct? 2/ The voltage (25.5v) at which the 'battery critically low' light starts blinking still seems quite high. Is the controller / BMS being unduly pessimistic? 3/ Is it possible to replace the cells in the battery, and if I do so with a type other than the original ?Li-Manganese? can the original Kalkhoff charger still be used to charge correctly? 4/ Any instruction or tips on replacing the cells would be most appreciated, including as a starter, how to open the case without breaking it (!). I can see 4 small screws which I thouht were Torx type but none of my torx bits fit. My thanks in anticipation of any advice.

Range vs Battery (AmpHour / WattHour) capacity in bike reviews. There is a very important aspect of simple physics which I feel is not given enough attention and that is simply the large and significant Potential Energy (qv.) involved in lifting any ("average", not overweight) rider of, say, 80kg up through a change in ground height. This has to come from somewhere and if not the battery, then from the rider's pedal efforts. Therfore I think an important point not sufficiently emphasised or noted is the rider weight and the total hill climb height tackled on rides. This can outweigh all other energy draws on the battery and these numbers perhaps should be stipulated and made clear on all reviews, even if the elevations tackled are a very very rough estimate. For example: To raise an 80kg individual plus 25kg bike weight up to the top of a half dozen 100ft hills (182.88m height change) will require [105 x g x 182.88] = [105 x 9.8 x 182.88] = 188,184 Joules. (g is the grav. constant near the earth's surface = 9.8 m/sec/sec). A typical 300Wh battery has the energy equivalent of 1080 KiloJoules. Therefore even assuming 100% efficiency in energy conversion through the motor, using a hub motor with a throttle (no pedal effort input), you would use up over 17% (188.14/1080 = 0.174) of the energy in your battery. And if the rider is, say 125kg, then this would use up 25% of your battery. Or put another way your battery (under ideal circumstances and inputting energy on its own) would be one quarter depleted just getting you up one 500ft hill plus one 100ft hill. And this is considering only the energy needed for change in vertical height before the adding in of other frictional energy losses and less than 100% energy conversion by the motor. One can also see why the weight of the rider makes such an enormous difference in the calculations, including consideration of number of stop-starts (building up kinetic energy of the bike+rider and then losing it). Without substantial energy input from the rider, the bike+rider would never manage any slopes for any distance. The 'average' fit looking 5'10" man would weigh around 80kg; just going up to 125kg in the rider probably mandates a 50% or even doubling of the battery capacity if it is a hilly area -- or the rider should get him/herself fit more quickly to get a reasonable range! Some might wonder what happens to all that Potential Energy acquired when you get to the top of the hill. Well, unfortunately it is all lost in heat (wheel braking) and air resistance drag when you go down the other side. You might be able to utilise a little bit of the acquired Kinetic Energy to carry you a short distance up the consecutive hill or along the flat at the bottom, but to all intents and purposes 99% is lost when you go down a hill. Still, the wind in your hair temporarily whipping past is a bonus!. Some physics info below (if it pastes alright..) I hope others also find I have done the arithmetic right in my first post to this forum....! Regards WR