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I was thinking more like 4 batterys only use 1 battery at a time you can always P them if you wanted more range. each battery will have its own bms. Each 16ah battery will take around 1-2 hours with a 10a charger so if charging 64ah with a 10a charger you will be looking at around 7-10 hours, ( the more P cells then normally the longer it takes to balance them ). personally I would not charge anything with over 1c ( unless its in a very safe area and you are watching it very carefully ). to maximize cycle life of batterys and keeping it a lot more safer i would go for a max of 0.5c i.e a 10ah battery charged at 5A max (2-3 hours complete charge/balance time ) to make full use of that charger you will need one of these https://hobbyking.com/en_us/1200w-psu-uk-plug.html edit: I was suggesting if you had £300 then you could have upto 64ah worth of battery :-) but you dont have to..

if you go down the route that i suggested i.e bms and the digital psu then you can get 4x 16ah 6s batterys and the charger , if you go for the10A psu this will give you a charge time of around 1-2hours charge time from completly flat to complty charged and balanced a 5A psu these times would be doubled. https://hobbyking.com/en_us/multistar-high-capacity-6s-16000mah-multi-rotor-lipo-pack.html im sure i have seen them in the uk web site but cant find them at the mo ... i know they used to sell them cos i have 8 of them :-) nope just looked through my orders with hobbyking and i got them from HK but i must have got them quick without much fuss or i would remember.

BMS is used for all li chemistery batteries, but you can monitor them yourself as you have stated, a bms takes all the hard work out of it.. you dont need 2 chargers as you are only using 6s so you can charge them as one complete pack. so yes a 450W psu should be fine for one charger . if you P4 3s packs then this will still be seen by the charger as a 3s battery but with 4x the capacity..the nice thing about using a bms is that the pack should never become totally shot as it will protect the rest of the cells from futher discharging, yes the battery will not work but will be saveable. you will need LV cell alarms for each cell group within the battery when you are using it and you must remove the lv alarms when not in use ( or they will drain the battery ) a bms is always connected and instead of a alarm it will just turn off the battery should any of the cells become to low.

yes that is the only draw back with having one big perminant pack , if a cell ( cells ) goes bad in the string then it will require battery surgery to remove/replace the bad cell (cells) this only applies to cells in P and the more P cells you have the more of a possibillity it would be for a cell to go bad , so this is something that you need to think about. If you have a bms then you dont require a balance charger , the bms is permantly connected to the battery and will all ways balance the cells when charging and will also prevent any cells from over charging. If you also bypass the onboard discharge current limit on the bms it is possible to have it control the bikes relay so should any cell drop below the safe level the bms will turn the bike off ( if you want more details about this let me know ) . you can still have a volt meter on the bike as a fuel guage. you can buy 24v CC/CV 5A psu's for around £20-30 that will be ok for a charger that is already mains operated ( they have a voltage adjustment pot on the psu as the output voltage will need to be adjusted to the correct voltage.... for 6s you will need 25.2v output ) or by a ebike li-on charger and ask for th evoltage to be adjusted. if you have the bms setup then there will be no need to diassemble the pack for charging , it becomes a plug'n'play setup. No i dont know th emax size of battery that can be fitted, sorry. this would do for a 24v charger .. ( but you would have to use a bms ) http://www.ebay.co.uk/itm/Adjustable-DC-0-30V-0-5-10A-Power-Supply-Precision-Variable-Digital-Lab-SA-UK-/262749264649?var=&hash=item3d2d139b09:m:m1J_LguXIITfnH-3ydJ-Yzw also i was just looking on ebay and you can buy a 60A 6s bms from china for £12.. ( if your prepaired to wait for it) , this can be just wired up as it should be to the 6s and 60A should be fine for the 12" 24v oset http://www.ebay.co.uk/itm/6s-24v-Li-ion-Lithium-Cell-60A-18650-Battery-Protection-BMS-MOS-Board-w-Balance-/331944218203?hash=item4d496ace5b:g:wLsAAOSwV0RXtZhj side note: if you opt for the psu i linked to as a charger then i would set the voltage then glue the adjustment knob so it can not be moved, or remove the knob alltogether.

or if it will fit just get one of these https://hobbyking.com/en_us/multistar-high-capacity-6s-20000mah-multi-rotor-lipo-pack.html the less interconnections you have the less room for error.. you may want to source a 6s bms for charging and basic battery protection.. you can bypass the current limit on most bms's for the discharge so you dont need to source a very expensive one..i think hobbyking sale a 6s bms but not to sure what the max charge current spec is.. 4A max charge bms https://hobbyking.com/en_us/6s-li-ion-pcm-charge-4a-discharge-10a.html 10A max charge bms https://hobbyking.com/en_us/6s-li-ion-10a-pcm.html

The proper way to fix this problem would be to make a circuit to remap the throttle output. There is a device 9n 5he marker called. A cycle analysis but these are expensive. I have witten the code for my home made ca that works out so much cheaper. My ca also has a volt/current/watt display it can also set the max current and set a system min voltage operation option. The parts cost around 25 quid.

The easest way would be to use a zener diode and resistor to.cap the max voltage from the throttle. How it is done by ost is just a pot but the troube with that is that it also alters the zero throttle dead band (like was siad in the previous post)

ok not that good specs for the price.. I would say that 18A/36A is not really enough for the oset16 .. maybe fine for a very small bike with a very light rider..

18A cont current is not very good and only 36A peak, what make of lifepo4's are they ?

its all poopoo .. a good electric motor will be good for any type of bike so its not just about a select market for trials bikes and it also dont cost that much to develope said motor.. there are already good motors on the market that just need a little bit of a redesign to take good advantage of water cooling. its all about making money without any new investment ( milk it until stock/demand runs out, just like cars and apple phones :-) ) . controlers and batterys are the real bottle necks ( controllers mainly )

just looking at that charger again yes it will need a addional psu to power it.

it looks like you will also need a psu for that charger as it dont make it obvious if its mains operated.. !! that will bump up the cost even more!.. the cheapest option is the one i suggested further back in this thread.. i.e a ebike charger ( with adjustable voltage for the different types of chemistry @ around £50 for a 5A charger ) a bms for the cell count/type you want to charge @ between £8 - £25 a box to put it in some wires and plugs @ around £15 then if you want alarms and a display will be about another £20 on top.. so a very versitil charging setup for around £100 + a bit of time putting it together. eg my 10A 48v balance charger setup cost £19.00 for the 10A CC/CV psu ( charger ) (ebay) £9.00 for the 12s bms ( for lipo ) (ebay) £6.00 for a nice box ( to put it all in ) (maplins) £6.00 cheap watt meter (ebay) £12.00 2x battery medics ( HK ) for monitoring the indivdual cells and/or increasing the balance current ( for a faster top off charge ) £8.00 2x HV alarms (HK) just for piece of mind £10.00 for wire and plugs so about £70 for a 48v 10A charger the 2 things that are unique for the voltage that you want charge is the charger and the bms the 48v psu that I have can be adjusted to cover 11s upto 14s lipo

yes those look ok.. I have not seen these before on the hk website, cust reviews seem good. what charger have you got to charge them if you go down the lipo route ? as 36v volt lipo (10s ) is a different top of voltage than 36v volt lifepo4 (8s) , there are a few types of 10s lipo bms on ebay but not many CV/CC 36v (lipo) chargers.

:-) the reason i asked because the link to the batterys that you posted was Austrailia... yes i see where you are coming from about the batterys, they do hvae the 4200mah in stock in the uk ( but check with them before ordering ) as I said you will have to get 6 of them to make up to the 8400mah capacity , just permently wire them in P in pairs to make up 3 8400mah batterys. just works out a little more expensive

so you are in Australia?.. got these is stock https://hobbyking.com/en_us/zippy-flightmax-4200mah-4s2p-30c-lifepo4-pack.html just works out a little more expensive as you will have to get 6.. make sure they have 6 in stock before you order. or you could go down the lipo route ?.. a bit cheaper,lighter,smaller,higher capacity.

You need to look for balance current and in the bms case in the link its 60mA .. the higher the balance current the quicker it will fully charge as the bms will not keep turning off should a cell go over the shut down voltage which is 4.20v ( which I hope is a typo in the link as its the same as the balance voltage, normally the shut down voltage is around 0.1v higher than the balance voltage spec) because then the cell needs to be bled back down to 4.05v before charging will continue and if the cells are out of balance by a lot this can take ages to do.. the reason I said to make sure it can bleed fast enough is that I have had some types of bms's that dont always turn off when a cell goes over voltage and they rely on the bled current to protect the cells from over charging but if you keep the overall top off charge current to a sensible level then this should not be a problem i.e set your charge voltage to maybe 50.45v ( for 12s lipo ) this should help stop the bms turning off ( unless you have a really out of balance cell ) but also keep the other cells charging when a cell is being bled. I have not run through the figures for the bms in the link but this is about where you need to start . monitor the cells as they become fully charged i.e 4.2v they should be held @ 4.2v and any low cells will still be charging , turn the current up or down ( well.... the voltage ( 50.4 -50.8v ) ) to find that sweet spot when you are still charging the cells even if higher cells are bleeding because if the bms turns off then its a long wait ( that cell needs to come back down to 4.05v ) before it come s back on to charge again .. Once setup then thats it but its that final charger voltage that is the key ( if its to low the battery do not balance and if its to high it can take a very long time to top off the battery.. so there is a bit of trial and error as no 2 bms's are the same spec ( even the same make bms's ) ... oh just remembered the clone MW psu's I have turn off the output when the output current is very low and this was a small problem for my setup as when the battery is near fully charged the current is near zero.. just keep that in mind.. i over came htis problem by just putting a permainat load on the output of the psu just enough to keep the output on. sorry to waffle on and i hope it makes sense.. Edit: If you want to get even more fancy with the setup what I done was to fit a break out socket from each set of 6s from the battery balance taps that I fit some 6s cell monitor alarms to when charging, this gives me the real time voltages of each cell plus the alarms i use also has a HV alarm that sounds should any of the cells go above 4.3v... or you can fit a couple of battery medics to the break outs, these do not have HV alarms but they do have a bleed/balance function so you can increase the bled current and also monitor the cell voltages.. either way its a good addition to have break out sockets on the balance taps.

that looks ok and will work... just one suggestion ... if the ignition switch (kill switch) is left in the on postion ( and using the main contactor to turn on ) the precharge becomes useless and the relay contracts will soon pit with arcing.

Its very important to have a mecanical disconnect ( contactor or relay ) from the batterys on a brushed system because brushed controllers do not always fail safe The precharge resistor is only used when connecting the battery to the main connector.. most controllers have a ignition wire so you need a small on/off switch on the ignition wire. With the ignition wire off the controller is off so the precharge resistor is only used to charge the caps in the controller once caps are charged there is no more current flowing until the ignition wire is connected and the throttle is twisted, so in theroy there is no loss through the precharge resistor, in reality there is a tiny bit of loss because the caps do leak a little so the precharge will keep them topped up. You can use a small switch ( push button ) on the precharge circuit with a led that will light to tell you when you can turn the main contactor to the on postion this will prevent that little bit of leakage. It do not really matter wheather you have it in the pos or neg of the circuit but you do need it as close to the main battery as possible.

I have a couple of 10A bulk chargers ( turnt down to around 7-8A output ).. ( mean well (clones) £20 from fleabay :-) ) and always use a bms connected to it just to protect the cells during the charging process, the bms's are cheap enough as you dont need them to be able to supply very high current for the discharge as they are only used for charging, i have 15A ( charge ) 12s bms also a 13s bms and a 14s bms.. if you go down this route for the first couple of charges monitor the voltages of the cells as if the charge current is to high and the bms's can not bleed the high cells fast enough than the cells are charging there is a possibility that the cells can over charge. once you have a good safe setup then the whole process becomes a very cheap plug'n'play setup. the taps are permently P'ed on my battery packs so there is less room for error and less ware and tear on the tap connectors.. cant stress enough to make sure that the bms you choose can bleed the cells ( when cells are fully charged ) faster than they are being charged!!

no you are not missing anything.. dependant on the psu's you can acutally parallel then to make a 10A psu but you will have to do a bit of digging on the web to find out how. the problem with having 2 12s packs and then joining them in P is if a pack ( 12s ) if faulty or a cell is bad withing the pack it will pull down the other pack (makng the second pack bad ) and could also cause a very large spark when connecting them in P. Also I would recomend getting a small 12s bms to use on the charger that will balance the cells and help protect from any over charging ( they are very easy to wire up and gives a extra margin of safety).

cost :-).. but sine controllers are coming down in price all the time and some are acually cheaper now than the trap controllers.. some also say that trap controllers are able to give a better instant hit than the sine contollers but in my experience I can not tell any difference between them as regards power delivery, as long as the sine controller is setup well. I have (used to have ) a self converted sherco . :-), well i still have it but its gone through many configurations/motors and controllers but at the moment its just a rolling chassis again.

its the type of controller that makes the noise in the motor... trapeziodal controllers are much louder than sinusoidal controllers.

I dont know much about how the em mimics a clutch but it is just a on/off operation so actually nothing like a real clutch. from my limited knowlage about the em I would say that it is just a throttle on/off control i.e the clutch switch turns the throttle signal line on and off. You will have to fit a pull down resistor on the signal line ( on the controller side 5-10k will be fine)

yes the switch is to disable the controller.. you can wire the switch to the controller brake ... not the contactor line.. remember that you will have to change the throttle type to a 0-5v pot throttle ( default i think is a hall throttle ). the fuse is just there to protect the wiring and will not stop any faults so as you have a battery of outputting 125A then thats what you should use.

its just the timing that determins the direction .. if the current/speed is identical in both directions then it has neutral timing but most are optimised for a spesific direction . I beleive that the timing can be adjusted on the oset motors, just not sure how easy it is to do with the oset brushed motors.