gwhy

I would measure the current at a fixed voltage ( not through the controller but just a fixed 24v ) with the motor running in the timed (default) direction, then just time it to the same current in the opposite direction , then you should be good to go. edit: or use a tachco and time it for the exact same speed at the exact same voltage ( just the motor... no load ).

30v sounds a bit to good for full load with sla's .. what you can do is measure the voltage at the motor full load.

you are correct about down grade the advertised C ratings of these batterys but.. dont get to bogged down by them . its all about internal temps and what is acceptable. A motor only pulls its max current when stalled or initially when under load ( current limitied by the controller ) if the C rating is exceded then the battery will warm up and the battery needs time to cool back down again normal running will only pull around 30-50A on average thats a peak of around 2kw. a higher C rating battery will have a better lifecycle but will not nessersary be any better for performance or battery safety as its all about how hot the batterys get when in use, you may gain a little bit more performance with a higher C rating due to the fact that the voltage sag should not be so low. so in a nut shell yes the higher the C rating the better for the lifecycle of the batterys and a very small increase in performance.

if its a 48v controller then it should be ok.. but dont quote me on that.. it should be good upto around 65v max . the problem with running a higher voltage than the controller is designed for is that the LVC will not kick in to protect the batterys so it will be nessersary to have a battery with a built in bms . yes 2 bats in P will be 100 peak but this still may not be enough especially if you are planning on 52v . also you will need to be carfully that the motor dont get to hot with the extra power

50 peak, 30 cont on a 20.0 will not be good enough you need to be looking for at least 100 peak minimum (may be even 150 ) , these specs will be goverened buy the BMS that is in the battery itself.

is there a small fan inside, these over time can start to make some very strange noises..

yes the motor would be fine, at that voltage but keep a eye on the temp of the motor if you intend to run it at the same current or higher.

Yes there are limits but they are well byond that of a ICE motor and this also depends on design and construction of the electric motor, Physically and electrically. Eddy currents play a major part in the max that a motor can spin and is one of the main considerations when using a motor at high speed. the smaller motors that I have run at 8-10krpm are 12 pole motors, but have used many motor types and configurations, the controllers I mainly use are basic 16khz and these drive my motors very well. Yes room temp superconductors would be the the ulimate! and can lead to 100%+ efficiency , this can then solve all power production problems as it will lead to overunity. The motors run at a max of 10krpm but this is a restriction of the bearings but have run them upto 14-16krpm not for perlonged periods as It starts to get a bit scary when motors are spun upto those sort of speeds unless they are specifically designed to do so.. 10krpm is the max rpm for full geared speed and is very rearly hit for trials but i have used them for small race bikes that are run flat out on a circuit and have coped very well with all the knocks,bumps and crashes.

The armature ( rotating part ) are magnets on a shaft, and the stator is copper wire and laminates in a shell... hardly a lot of components ( unless you are talking about brushed motors ) There is very little restriction to the speed that a electric motor can run at unlike ICE so why not run them at 10krpm to produce the torque ( its what I do ) then the motor can remain small and light . and if designed right cooling them is not a problem ( if needed ). Yes batterys ( and controllers ) are the bottle neck as regards EV's but in real terms if you can recharge a battery in 10mins ( if you had the facility's ) then whats the problem . The weight of current batterys that will allow approx 1-2 hours of typical trials weighs around the same weight as a gallon of fuel and takes up about the same amount of room and a typical trials ICE weighs around 15-20kg , So you are saving weigh on the power plant with electric ( some electric motors that only weigh 4kg can peak at the same power that a trials bike can produce ) . If you what speed, power and range this is where things get a little more complicated as you need to fit more battery capacity to the vehicle and on a bike this becomes a problem with space, But battery tech is getting better, smaller and lighter and most of all cheaper, maybe fuel cells will be the brake through that is needed but at least the power plant will not need changing.

Simplicity ! .... you got to be kidding .. 1 moving part in a electric motor ( 3 if you include the bearings ) .. reliablility ... with only 1 moving part in a electric motor,reliability is going to be better Manufacturing cost ....its got to be cheaper to make a electric motor with its very few moving parts and the much reduced weight and size. power to weight ... Electric motors wins hands down , if you dont think so then do some research efficency maybe a very good 2T can achive 65% but even a bad electric can achive 90% Yes modern 2T can run very clean but you still would not want to suck on the end of the exhaust pipe In the short time that I have been involved with the develoment of EV's I have seen the development of battery tech come on leaps and bounds .. halved the size, 3rd of the weight, doubled in capacity and higher discharge rates.

I would want to know more about those bikes and the battery i.e is it a standard configuration or is the battery unique tot he bike as 8Ah is not going to get you very far unless the bike is very under powered.

The batterys are not a weight problem .. they are very light for what they can produce its more to do with space. The EM is very heavy for what it is and the motor is a main contributor to this. Hybrid cars are configured the wrong way round as most are gas as the primary which is not so good as gas is not very efficent and dont produce torque like electric. There was a prototype hybrid car in 2006 developed in the UK that claimed to produce 300bhp had a range 300miles on 1 liter of fuel between a full recharge, the top speed was not that great but more than enough to get your licence taken away from you, it was poo pooed by the uk goverment on some red tape thing and also BMW as it was based around the BMW minicooper so was never allowed to go into production, this was a UK designed electric car that ticked all the right boxes but it was shut down ( I wonder why ). and now the motors and tech that was developed in the UK for the copper are now no longer available in the UK , there are some of the features of the original concept now appearing on Audi, BMW and Merc's but the electric motors are now made in Germany and not for sell to the public.. go figure The Car manufactures have the tech but dont want to use it yet as they have to much investied in there engine factories . Bikes are a little different due to space restrictions so i dont think you will ever see a true hybid bike as it all just takes up space that can be used to fit more battery's.

nope ! but apart from that dont look to bad.. not enough information in the spec to work anything out, but looks a good solid starting point to upgrade :-)

there is nothing magical or new about these packs they are no safer or more hazardous than a pack that you can put together for half the price with all off the shelf parts.

it looks like the controller is only torque/current control , I don't know what the load type means ( maybe its related to mixing the torque and speed functions ) and what effects it will have on battery current as I have never had one of these controllers to test. As I said when altering the gearing in relationship to capacity its not linear so I am not that surprised in the reduced run time for the increase in speed.

you can not have the same performance and increase the runtime only by increasing the Ah's, the efficency of the motor dont really effect runtime that much it will be more to do with heat generated by the motor at a given rpm/load , so that wasted heat is power that is not being put throught the wheel.. the options are you could turn down the current limit to increase the runtime if set to 60A @ 40v this is 2.4kw you could reduce this down to 30A @ 40V for 1.2kw .. this will give you the same top speed but will take a lot longer to get there as it will have reduced torque the increase in runtime may still not be that great so ideally you will need to gear it slower and also reduce the current limit ( you need to reduce the current limit as it may become to twitchy on the throttle ).. do you have a mixed mode option in your controller settings ? .. this is where the throttle is a mixture of current based control and speed control.. this will help increase runtime depending on riding style or even setting the throttle to a current based control only may help.

i would be very careful trying to recover a lipo... first thing is what is the total voltage across the main discharge wires of the battery ? if its only 14.78 then You have a very poorly cell that ideally needs to be removed and replaced, but if the total voltage is at least 2.5v higher than 14.78 then its more than likely that you just have a bad balance tap wire and this would be the thing to check before trying anything .

no nothing more to do 40v x 55A = 2200w peak.. keep a eye on heat of the motor, if not getting hot then up the current at 5a ago.

the loss will not be linear ,so loss in battery capacity may not be as much just because of the fact that the controller is limiting the current. but the motor will get warmer due to increased gearing but again this may not be a issue because you are running at reduced potential. You may not need a different motor if its possible to gear it the final speed you desire ( rather than using the speed pot to reduce the speed ) as you are not making the most of what you have atm .

you would need to fit a temperature probe to the motor and ideally inside the motor where it will get the hotest need to be careful that the probe can not get caught on anything that is rotating.. some people use a bbq thermometers to monitor motor temps as these can read quite high temps. the faster it is geared for then the more capacity will be used from the batterys , even if you are not getting upto the geared speed on a regular basis this will be because the motor will be bogged down for longer whilst getting upto speed,, if that makes sense.

you need to find the sweet spot for power, speed and motor temp.. motor temps can get very hot very quickly , the only thing I can say is if the motor is warm to the touch then it will be roasting inside ( brushed motors more so ) its good that your motor do not get warm but its prob not hitting the current limit very often as your lad is light , the best way to test is if you ride it up a hill from a dead stop maybe 30-50 yards @ WOT then see how warm/hot the motor is. by gearing it faster it will increase the time it will be at the current limit so this will generate more heat, and this will also be the same if you increased the current limit of the controller. Also if the speed is only set to (e.g) 50% @ 40v @ 40A setup (800w) then that is halve of the max power that can be put into the motor i.e equivalent 100% speed @ 40v @40A (1.6kw)

yes but its reaching that torque using only halve the power and halve the speed so achive the same torque if put on a bike geared higher to achive the same speed as if run at 60v but this will then halve the torque at the wheel .. you also need to look at the speed when working stuff out as regards torque. yes a 350A burst will be ok and will prob be way to much for a light rider and bike if geared for only 40-45kmh but you can always turn the the current down :-) if you look at the raffe bike that is running a phase current of around 200A and battery current of around 100A and geared for around 60k and it will bite a light rider if its a 100A brushed kelly then you can run upto 100A and this is what you will get .. but a brushed motor will burn up very quickly if it gets bogged down or over geared.. may be fine if geared for only 40k but watch the temp of the motor.

in short yes it will be enough for a light kid.. the revolt generates more torque because its a bigger diameter motor .. brushless motors are nearly always more efficient and lighter than brushed motors, remember that the graphs shows the revolt with 60v input and that is appox 1.5x more voltage than the brushed motor is showing so both the graphs are not like for like i.e if the brushed motor was run @ 48v then it will generate more torque and because the speed will double then if you gear down to match the 24v speed then this also increases the torque. there are also a lot more other factors that come into play but more to do with heat and losses. but in general a brushless motor of the same kv and diameter or bigger will always be better than a brushed motor as long as the controller can handle the current for a kelly controller to be able to get max torque out of the revolt in that graph it would need to be able to handle around 2.5x the max battery current and this is where things start to get a little more complicated as the brushless kellys are advertised with max phase current ratings. edit: a 100a brushless kelly contoller would be more or less the same spec as a 40A brushed controller

ok 45kv is ok but as I said the slower the wind the less torque it can make depending on gearing.. if its geared to high then it will get hot, for that diameter motor (120mm)@ 45-50kv you should still looking at around 3-4kw with 8kw bursts. the golden motors are very heavy :-) thats all im going to say about them and also dont bother with the WC version its not worth the extra cash.

Kv is the RPM at which a motor will spin per volt , if a faster motor is geared down in speed the this gears up the available torque ( can be just gear ratio between the front and rear sprockets ) , 120kv of the revolt is quite high so would need a fair bit of gearing down compared to the standard motors which are around 60-70kv... the higher the kv = lower winding resistance therefore thicker wire can be used so can take more current. .. outrunners also tend to have a larger rotating mass than inrunners of the same physical diameter. magnets remain cooler with outrunners. Outrunners are not the best design for use on bikes as they tend to be quite open to the elements and debris can enter the motor. Yes any hall throttle should work.