January 20, 201016 yr Its 15Ah Herb, range over 30 Miles. I've not been out on it for while due to the weather but will make a note next time I use it...
January 21, 201016 yr Author Ok just got to work (the Marathon Plus held out) and I tried to pedal a little more though still used power on inlcines and when I felt lazy. This meant that when I got to work only 0.916Ah was taken out the battery. Usually its about 1.2Ah. I won't charge the battery and we will see if I can now get home on one charge and no more punctures Regards Jerry Edited January 21, 201016 yr by jerrysimon
January 21, 201016 yr Author Well got home tonight and I had taken another 0.895Ah out the battery. So that's a total of 0.916 + 0.895 = 1.811Ah. The battery still had plenty of power in it as I pulled up to my front door and had not started to cut out. From my previous ride where it did start to cut out I am guessing that this happens around around the 2.0 to 2.1Ah point. I may have assisted more but certainly nothing that really pushed me hard, arriving at work and back home refreshed but not exhausted. I then put 1.768Ah back in on a subsequent charge, which is all but 0.043Ah the same as was taken out. I have therefore concluded that this battery more than meets the requirements for my 10.25 mile round commute on my lightweight EBrompton conversion and I don't even need to charge it at work. As I have said though this is in Cambridge where my commute is pretty flat apart from a few inclines, certainly not steep hills. I guess this thread is now over, apart from the occasional update of how the battery performs over time Regards Jerry Edited January 21, 201016 yr by jerrysimon
February 1, 201016 yr PS My A123 cell suppliers now sell rather nicely made up 6s packs here Regards JerryI thought this might be of interest to DIYers, electricwingman are selling ready made A123 packs... A123 battery packs - Single cells and 2-8 series They are offering lots of different configurations. 6s packs are priced from £69.90 to £79.90. Uk-based, too. Chris.
February 1, 201016 yr Author How do you build the BMS needed to charge and maintain the battery? Thanks. If you read the whole thread you will see that you may not need one for these cells, A123. Regards Jerry
February 1, 201016 yr If you read the whole thread you will see that you may not need one for these cells, A123. Regards Jerry I kind of suspected as much, I was thinking that a Turnigy 6 cell charger/balancer might do the trick. I will read through the whole thread now. Thanks.
February 2, 201016 yr Author ELECTRIC AVENUES, I am not sure you even need the Turnigy. Although I used it initially to balance the cells I have not used it since. The cells seems to naturally balance after use. At the moment none of the cells are more than 5mv out after several weeks use. Regards Jerry Edited February 2, 201016 yr by jerrysimon
February 2, 201016 yr ELECTRIC AVENUES, I am not sure you even need the Turnigy. Although I used it initially to balance the cells I have not used it since. The cells seems to naturally balance after use. At the moment none of the cells are more than 5mv out after several weeks use. Regards Jerry Thanks Jerry....where do you get those {and what are they called } little clusters of wires with the fitting that plugs into the Turnigy??? Cheers.
February 2, 201016 yr Author ELECTRIC AVENUES All the details and links are in the posts if you read back through them Regards Jerry
February 2, 201016 yr ELECTRIC AVENUES All the details and links are in the posts if you read back through them Regards Jerry Hey, thats one way to make a man read your book!! Cheers!!
February 20, 201016 yr Jerry, I have a question about your ebay-sourced charger... have you checked out what voltage it gives out? If you remember, I asked you about Tongxin motor supplier in the past. Now the motor has been ordered along other things (like spokes, rim, nipples etc.). I'm hoping to get something done for the project in the following weeks. Regarding battery I think about 4,5 Ah is big enough capacity for my use. Maybe I'll buy 2 Turnigy lifepo4 packs (2p6s) and connect them in series or even go your way and use individual cells. Anyway I was wondering if I could use my existing 36V SLA charger to charge this series-connected pack easily? I could then separate it in two and balance both packs occasionally with cheap balancing charger. My current charger gives out these voltages: 41,7 V (measured from charger connector not connected to the battery) 43,7 V (initially when connected to the slightly discharged battery and charging going on). The voltage continues to rise slowly until the green light lights up. Voltage was checked from Turnigy power analyzer screen. 41,4 V (charger has green light and the battery is charged ready). Checked from Turnigy power analyzer screen. Bottomline, are SLA and lifepo4 chargers basically the same? EDIT: I checked ebay and there was this charger: 36V 36 Volt Electric Scooter bike Razor Charger ATV : eBay Motors (item 320489157828 end time Mar-18-10 06:02:51 PDT) In the picture there is mentioned "equal changing voltage 44,5 V". So this is cut-out voltage, am I correct? Seems to be a little on the high side: 44,5/12=3,71V per cell. A123 charging cutout should be 3,6 - 3,7 V. When I now checked your earlier posts, the specifications are the same as yours. Has the charger been working fine and do you think it is safe to use daily without worrying about overcharging? Edited February 20, 201016 yr by trepo
February 21, 201016 yr Author trepo, That is the same seller that I purchased mine off. I basically checked out the one that Freedom used and sourced the same model. Its been charging fine the green light coming on after about 1-1 1/2 hours after charging following my commute. I used the the charger/balancer initially but to be honest these A123 cells seem to self balance really well and I think just using the cheap charger will suffice. Your SLA charger sounds identical and this one IS sold as an SLA charger. Anyway I will continue to report on battery usage. Did you order your Tongxin from my same supplier ? Hope you get the right one with no roller brake fitting. Be sure to keep us updated Regards Jerry Edited March 8, 201016 yr by jerrysimon
February 22, 201016 yr trepo,. Did you order your Tongxin from my same supplier ? Hope you get the right one with no roller brake fitting. Be sure to keep us updated Regards Jerry Jerry, I indeed ordered from the same chinese company you did. I paid using westernunion on Friday and now after weekend their tracking page shows that the payment has been picked up. I have never used westernunion service before but it seems to be quite handy, although expensive. I mean the service fee was 26,50 euros and exhange rates are worse than payng by credit card. Regarding batteries, I have decided not to use ready-made turnigy packs. It seems that they are not very high quality, at least according to this user: Endless-sphere.com • View topic - New Turnigy liFe packs Instead I have ordered 8 used Dewalt 36V packs from Germany. Daniel Weck has hinted us of it here: http://www.pedelecs.co.uk/forum/electric-bicycles/5197-public-service-german-supplier-dewalt-a123-bosh-fatpacks-powertool-batteries.html Those packs have genuine A123 cells inside and after disassembly there might even be ready to use 6s sections, so I only have to add balancing leads etc. The seller states that 10-20% of cells are bad so probably I'll end with well over 60 cells to tinker with... That's maybe 10 6s packs. And I can re-cell my dead cordless screwdriver battery using those cells too. The seller was very friendly and helpful and answered my questions promptly even while it was Sunday afternoon. My packs are already on the way and will be here probably next week. I will start my own thread about Brompton build in more or less diary style later. EDIT: An offtopic question: I bought my Brompton from ebay a few months ago for a very fair price. It was a insurance replacement for a stolen one. I have not used my Brompton extensively yet, its winter here and a lot of snow (I did a short testdrive though and everything works fine). The bike came its right pedal not attached, it was in the package separately. Is it normal that the metal cage is shaped like this, or should I try to straigten it? brommie Edited February 22, 201016 yr by trepo
February 22, 201016 yr I will start my own thread about Brompton build in more or less diary style later. Looking forward to this ! I bought my Brompton from ebay a few months ago for a very fair price. It was a insurance replacement for a stolen one. Mine was too Is it normal that the metal cage is shaped like this, or should I try to straigten it? It's a cheap part, so not a big deal if you can't straighten it up. Cheers, Dan
February 22, 201016 yr Author trepo, I look forward to watching your build thread/diary. Lots of pictures needed The round A123 cells are more robust it seems than the Turnigy lifepo4 packs so I think you have chosen wisely. Did you order a couple of motors as the cost of postage is the same for two or even three, so it worthwhile getting a spare ? PS it took about 2-3 weeks for the motors to turn up after they withdrew my payement. Like you I used westernunion which does require an element of trust but they seem genuine. Although it will probably be delivered without an import/VAT charge I received an invoice from DHL in the post about 2 months later. The actual charge was quite small about £10 I think and no admin charge. I ordered two full sets of everything. Regards Jerry Edited February 22, 201016 yr by jerrysimon
February 22, 201016 yr Daniel, I just fixed the pedal. Some pressing on a bench vice & light hammering and it was as new. A question about connecting 6s packs together to get a bigger capacity pack: If two or more 2 x 6s packs are connected parallel like this: . . . . . . . . . . - 6s A123 - 6s A123 - . . . . . . . . . /. . . . . . . . . . . . . . \ negative out . . . . . . . . . . . . . positive out - main fuse 15A . . . . . . . . . \ . . . . . . . . . . . . . . / . . . . . . . . . - 6s A123 - 6s A123 - What if one cell in any of the packs short-circuits itself? If I get it right the other half of this big pack starts to charge the other half with a high current ruining the whole pack / maybe melting the connectors etc. Maybe I should add a fuse just before parallel connecting them like this: . . . . . . . . . - 6s A123 - 6s A123 - 10A Fuse . . . . . . . . . /. . . . . . . . . . . . . . . . . . \ negative out . . . . . . . . . . . . . . . . . . positive out - main fuse 15A . . . . . . . . . \ . . . . . . . . . . . . . . . . . . / . . . . . . . . . - 6s A123 - 6s A123 - 10A Fuse 10A fuse would blow if something like that happens. It would be easier than using diodes because fuses and holders for them are readily available anywhere.
February 22, 201016 yr If two or more 2 x 6s packs are connected parallel Tiberius will supply Ideal Diodes for parallel battery connection, you will find them in the classified section with lots of links to help you. Herb
February 22, 201016 yr I have a 2.3Ah A123 pack in my collection, if I had two I would be tempted not to parallel them but run each of them as a single battery until the LVC operated and then change to a fresh battery. This way you would always know your remaining capacity. I run my Brompton on 2 parallel (with diodes) Bosch Fatpacks and use the A123 as a sort of reserve/get you home battery. Look forward to seeing your build. Herb
February 22, 201016 yr trepo, I look forward to watching your build thread/diary. Lots of pictures needed The round A123 cells are more robust it seems than the Turnigy lifepo4 packs so I think you have chosen wisely. Did you order a couple of motors as the cost of postage is the same for two or even three, so it worthwhile getting a spare ? PS it took about 2-3 weeks for the motors to turn up after they withdrew my payement. Like you I used westernunion which does require an element of trust but they seem genuine. Although it will probably be delivered without an import/VAT charge I received an invoice from DHL in the post about 2 months later. The actual charge was quite small about £10 I think and no admin charge. I ordered two full sets of everything. Regards Jerry Thanks for encouragement, Jerry! I only ordered one motor because shipping fee quoted was 150$ for one and 250$ for two, the kit itself was quoted 140$. How well Billy communicated with you during the order process? I can see that my payment has been picked up and I asked him if he has got the money, but no answer yet... of course I understand that he might have something more urgent going on than just a order of one motor to european private customer. Shame we can't get these motors from Europe for decent price. Did you get a detailed invoice by mail (I think that will be needed for customs office once the kit arrives)? I specifically asked to get a motor without that splined part and with shorter axle, we'll see what's in the package (hopefully) in a few weeks.
February 22, 201016 yr Author Thanks for encouragement, Jerry! No problem. Billy's english was not bad and communication is good. When I realised I had ordered the wrong one we had extrensive email exchanges though I could not seem to explain about the roller break flange unfortuanately. He does seem to now understand though as I have since spoken to him a few times about it. There were a few times when I did not get a response for a day or two. Remember their Chinese New Year celebrations have only just finished. As I said he has proved reliable to date. The invoice was complete with the package, so DHL will sort it out don't worry. Its a step of faith to order I know, but I am sure it will work out At least I have led the way already and you can learn from my mistakes lol Regards Jerry Edited February 22, 201016 yr by jerrysimon
March 7, 201016 yr A123 Build, Large-Scale, Advise and Help Needed!!! Hi again, I thought I would post this here as a follow-on to Jerry's own A123 build thread, as this will be larger scale. I cannot do it on my own :o , and it could also serve as a valuable guide to anyone who attempts a similar project. I expect to get 44 A123 in the post tomorrow, and another 20 in a week or so. They are not the green tabbed ones that Jerry had, 40 of them are left-overs from a job-lot that an American user had from building a motorcycle and the remainder were harvested from some Dewalts. That will bring me up to 64 cells, though I expect 4 of them to be bad, from the Dewalts. So call it 60 cells. I have an Aotema Senorless Hub, the controller can handle around 30A and 50 volts or so. My overall goal is to find a way to make up individual packs such that they can be joined quickly and then chopped-changed into larger packs {let's call them batteries} of varying voltage and capacity, from say 72v 4.5Ah to 48v 10ah, as an example. I was looking for, initially, a list of everything I would need to start making the base packs. Charging will be via an 8-plug Turnigy Accucel.... http://www.rfmodel.com/upload/data/image/accucell-8150.jpg I understand I will need a power supply for this...can anyone recommend one? Thanks. Can anyone recommend a source of good balancing strips? How should these be soldered together? Do I need to get some copper strips, or nickel strips? I will leave it at that for the time being, many thanks indeed. If anyone has any questions about anything, just ask. Thanks. Edited March 7, 201016 yr by ELECTRIC AVENUES
March 7, 201016 yr Author ELECTRIC AVENUES, Any 12v power supply for the Trunigy should fit the bill. Depends on how fast you want to charge them and the max charge current of that Turnigy 7amps ? Faster charges will require more amps. I would say min 2amp power supply. I use an old PC power supply that I have adapted that outputs 12-15v at 5amps max I think. But you can buy cheap ones of ebay for less hassle. Like this In terms of balance taps depends on how many cells you are going to put in each pack. With that charger you can do 8 max I guess. Earlier posts in this thread give links to 6s balance taps. My 6s packs have not needed balancing since I first completed and balanced the cells some 20 charges ago. Each cell has remained within a few mV of each other. That said I am not really loading then that hard drawing on average only about 6-7amps. If you want to charge them all connected together though your going to need a charger that can charge to whatever the voltage is. Soldering direct onto the cells is possible but you need to be carefull. Again I think there are some earlier links in this thread for advice. I would also test each cell first to make sure they are all similar voltage/charge before you start connecting them all up. Hope that gets you going. Regards Jerry Edited March 7, 201016 yr by jerrysimon
March 7, 201016 yr ELECTRIC AVENUES, Any 12v power supply for the Trunigy should fit the bill. Depends on how fast you want to charge them and the max charge current of that Turnigy 7amps ? Faster charges will require more amps. I would say min 2amp power supply. I use an old PC power supply that I have adapted that outputs 12-15v at 5amps max I think. But you can buy cheap ones of ebay for less hassle. Like this In terms of balance taps depends on how many cells you are going to put in each pack. With that charger you can do 8 max I guess. Earlier posts in this thread give links to 6s balance taps. My 6s packs have not needed balancing since I first completed and balanced the cells some 20 charges ago. Each cell has remained within a few mV of each other. That said I am not really loading then that hard drawing on average only about 6-7amps. If you want to charge them all connected together though your going to need a charger that can charge to whatever the voltage is. Soldering direct onto the cells is possible but you need to be carefull. Again I think there are some earlier links in this thread for advice. I would also test each cell first to make sure they are all similar voltage/charge before you start connecting them all up. Hope that gets you going. Regards Jerry Cheers Jerry. I was going to charge/balance each pack, once at a time. Maybe get two accucel. It is a real one-off job. These A123's are going to be the "flagship" of my battery collection. 8 cells to a strip, two strips per pack, each with a balance tab, encased in heat-shrink, and with 2 power wires for each. That's 16 cells, then. Suppose now that each 8 cell block provides 24v@2.26 Ah. Thats 8 in series. 24v {just taking the round figure} per strip. What I am wondering is IF I have a choice between the overall pack {of 2 strips} being a 48v 2.26 Ah unit or being a 24v 4.5 Ah unit, if you see what I am saying. In other words, can I connect sells in series into columns, and then connect those columns into parallels within a pack, and then connect the packs themselves in parallel or series as I see fit. Or is all this a departure from scientific reality?? :confused: Thanks again.
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