Hi Folks (from the Perth Electric Skate FB page if you've made it here)... Ok so, I love/hate* my evolve's ! Love the way they ride, hate the way they break down... The goal for my new board: - ~40km (real world km's) on ATs, - ~60km on streets, - top speed ~45km/h, - high quality parts, - 18650 cell battery (minimal sag), - shorter deck / maple / wood / whatevs, I've got a rough outline / shopping list, of those who've built a board / battery or are keen, I'm interested in all your feedback! (and any parts I've missed, connectors etc).. I've got the 'hardware' sorted (incl some evolve GT supercarve trucks (the 'love' part of the evolve equation)... I'm planning on a 10S6P 18650 battery, 'double decker' if you like, 30 batteries on 30 batteries.. possibly an evolve battery case with a thick spacer. Won't look at bad as it sounds, will be shmicko out of ply. Deck to be top-mounted (not drop through) with risers, so the ground clearance won't be an issue. Motors: Motor 6355 190KV x2 from diyelectricskate, 2 VESCs, a VESC XT90 Parallel Connector, a VESC CanBus Connector and Male to Male servo connector, 10S 60A BMS from battery supports, on/off switch from diyelectric.. I think that's about it? Pricing everything up it's $1,750 on the button (if I can exchange someone their battery spot-welder for a carton of their choice of finest beer!)
Andrew -Good Luck with the build. Sounds like you have been doing quite a bit if research and reading. What motor pulley and wheel pulley are you looking at?. The motors you are looking at are pretty high power (2.5kW each) and weigh 1kg each with 80A max current. For a 6P battery this is 13.3A each cell (assuming all parelell cells share load current equally) which probably means you will need cells with max discharge of 20A. My MJ1 are 10A but there are a number of cells with 15 or 20A max discharge. The other option is to go for a 8P setup like mine or reduce the motor power a bit . There are quite a few BMS units that have an inbuilt Mosfet switch -saves you buying a separate switch. Are you looking at a smart BMS with comms or just a basic unit? Cheers
I had my eye on this bms Roger: 36V 37V 42V 10S 60A 10x 3.6V Lithium ion LiPolymer Battery BMS [36V 10S 60A Lion LiPO BMS] - $38.00 : Lithium Rechargeable Batteries, Battery BMS, Pack Assembling As for the motors, 1kg each! Jeez.. would probably be overkill for me and I'd be happy to knock them down in spec a bit. Trying to balance great performance w/ budget and the practical side of things. It's all the Amps & Max discharge etc that I get a bit lost on. For now, std evolve pulley, might get less teeth down the track. Motor pulleys, I'll graba few different ones from RS components online and see what suits. Have you for higher top speed or better accel on your build?
Andrew - The BMS above is 60A max so you will not be able to run the 190kV 6355 motor at its max current of 80A. (a waste of installed motor power) Need to lock in motor first then make sure that VESC and BMS can supply at least max current of motor then consider battery cell requirement FYI - The motor KV = rpm/volts so a 190KV motor with say 40V applied = 7,600 rpm - then work through the motor pulley/wheel pulley teeth ratio and efficiency to get wheel speed - then take wheel circumference to get km/hour. For BMS - need to decide if want smart one with comms ( and iPhone/pc app connection) and adjustable settings or just a fixed settings one For my DIY (in the thought stage only) - I will be going for a smart one with an inbuilt switch with separate charging mosfet to motor mosfets A few BMS options are below - there are many out there! One with Bluetooth and iPhone app Smart BMS 10S~15S 60A with Blue tooth Android APP - BMSBATTERY A bestech one for 80-A 37V 10S Protection Circuit Board for Li-ion and Li-Polymer Battery Packs Another 80A smart one with comms BMS with SMBUS ,UART, RS485, CANBus Communication protocol ,Battery BMS/PCM/PCB for 10S 37V Li-ion and Li-Polymer Battery Packs,Programmable BMS A 150A monster with comms Battery Controller S516 150A/750A | Energus Power Solutions Cheers
{} Nice one, I'll have a look at that 80A BMS. Here's a rough diagram.. still got a lot of questions and what connectors are required etc.. mainly around how the on/off switch hooks up and the charging port.. With "all" the variables open (motor, BMS, VESC, pulleys etc) it seems I've got to lock in one. I'm pretty set on a 10s6p battery.. Not sure I want motors 'too' small?... Any idea what evolve's current GTs are? They don't seem too bad if there was a more reliable model available.
probably the 'non' intellegent BMS at this stage.. one less thing I'd have to tinker with.. Feeling that for the first 'complete' DIY building he battery and hooking it up to a BMS wil be enough of a task
Andrew - The stock GT Evolve motor is 150 KV 5065 ( 50mm diameter 65mm long) approx. 1,500 W weight 480g Max Current 35A . With this motor and 15T motor gear 32 teeth wheel gear and 97mm wheel the top speed will be 45km/hr. If you are happy with the torque from the GT ( acceleration and maintaining speed going uphill in GT mode ) not withstanding the appalling voltage sag - maybe stick with these motors . The evolve BMS limits motor current to 30A or about 65A in total for BMS rating. There is a slightly bigger wattage motor 200kV 5065 Max current 45A 1,700 W which will give you slightly more torque if you get gearing to match stock gearing. These are A$54 from China and identical physical dimension /size as stock Evolve motors. For your 190kV 6355 motors - there are a few different ones around but most say 2,400 W Max current 80A - so you will need a BMS of at least 160A and at least a 10P battery pack and some very heavy nickel strips and wiring to supply 160A. If you want a bit more torque and speed than stock evolve maybe go for 200KV 5065 motors with two 50A VESC and a 100A BMS - with a 6P battery = 17A max discharge per cell - which is doable with a 20A max discharge 18650 cell. If you use 3,000mAh cells - assume that you can get 2,700 mAh effective Ah down from 42V to 30V and if you adopt 10Wh/km as average power consumption on ATs a 10S6P pack( 60 cells) will give an estimated range of approx. 58km . For streets - a power consumption of 7 Wh/km gives estimated range of 83km. BMS connections are fairly standard and relative simple. Charger +ve connects directly to +42V of battery pack and Charger -ve connects to BMS ( for charging control) so your diagram above is correct. Lots to consider ! Cheers
Lol, Roger, next group ride the coffee is on me! Thanks for all the info. So the selected BMS needs to be able to cope w/ the maximum A (Amps?) of both motors combined? Here I was thinking that the 10S 80A BMS was already looking too big! :/ I don't mind the Evolve motors to be honest, performance/GT mode etc.. they seem to go pretty well. If I can find a 100A BMS with a small(ish) form factor the 200kV 5065 Max current 45A 1,700 W motors you mentioned could be a good option. 10S6P is locked in for the battery, 'double' thickness, just haven't chosen the cells yet. Guessing I need to lock in the motors (+wheels & pulleys) first. On the diagram above I'm still a litle confused as to how the charger (+) splits off to both the battery and on/off switch.. Today my deck arrived, have already sourced the trucks, bearings and wheels.. Think there's going to be a rather large purchase from diyskate/torque boards once I've finalised the motors. Thinking the smaller ones for a more manageable BMS. Are the chinese ones you're referring to on AliEx? M something... Maytech! That's the one. Also confused about sensored motors vs unsensored, Thanks again for the help P.S. ->> looks like this one? New Arrival Racerstar 5065 BRH5065 200KV 6 12S Brushless Motor Red Without Gear For Balancing Scooter-in Parts & Accessories from Toys & Hobbies on Aliexpress.com | Alibaba Group (link shortened).. doesn't come with the mounting fixings though, will have to check how the current evolve motors are bolted to the motor mounts.. didn't think there was much to it.
(Roger's) Engine Selection / Calc: Max Current 46A, x 2 engines = 92A 92A / 6 Cells = 15.3A Max Discahrge Per Cell Motor KV = 200kV = rpm/36V, rpm = 200kV x 36V = 7,200 rpm The motor KV = rpm/volts so a 190KV motor with say 40V applied = 7,600 rpm Wheel Pulley = 32 teeth (std evolve GT) Motor Pulley = 20 teeth (RS Components) Ratio 0.625 Top Speed 50.74kph w/ 97mm wheels ? (Assuming 100% battery efficiency)... I think I'll have to get myself a pair of brown trousers at 50kph (!) >> Then found this calculator online Superblog: Electric Skateboard Calculator
The Charger socket +ve connection effectively goes to the battery pack +ve and the battery pack +ve supplies +42V to the on/off switch power input. In my build I have a fuse for +ve charger connection ( see my wiring diagram on blog) Cheers
Yep - That the one. Keeping to 5065 size means that if you have a motor failure you can replace with a standard Evolve motor or a few people have Racerstar 140kV 5065 motors as spares - but you will need to reprogram VESC to limit motor current to 30A if using these. I think Evolve sells the motor mount from their on-line shop ( another benefit for sticking to 5065 frame size) The small plug on the motor leads is for the Hall effect connection - this device effectively tells the VESC physically where the motor rotation is at. Need to check compatibility with the hall effect device and the chosen VESC. I think the hall effect connection may be optional on some VESCs. Cheers
Andrew Just remember that for a given motor power - the lower the gearing ratio is - the lower the torque is at all speeds - so no point in giving up some torque ( for acceleration and going up hills) to achieve a top speed that you may never use . At the moment - 35km/hour is my brown trousers speed ! Cheers
Andrew Suggest you buy one of these and set it up with charging socket and plug so you can monitor what's going on . DC 6.5 100v 20A LCD Combo Meter Voltage current KWh Watt Panel Meter 12v 24v 48v Battery Power monitoring-in Voltage Meters from Home Improvement on Aliexpress.com | Alibaba Group Will also be helpful for the battery pack discharge test to verify cell capacity You can also measure mAh and Wh for each charge to get an idea of what a particular ride consumed in terms of Wh
Andrew - Another calculator at http://calc.esk8.it/ This gives different nos to your top speed quoted above ( approx. 85km/hour) Is you number in miles/hour? Better to use 37V in calculating motor rpm and 85% efficiency is what people use. Cheers
An ABS Enclosure to consider Split low pro V3 27" by Psychotiller | Electrical Longboard Supply | California
the battery enclosure is my biggest (of many!) concerns lol... I think it's the thing that can make or break a DIY build. I think evolve might have it by the jaffa's here. But i'd need to make a gasket or similar to get the extra clearance required.. Lots of info about vaccuum forming etc but think that'll be a bit too much on the first build. WIll check out the stuff from Psychotiller, good call.
Looking at evolve's case, I think it's available in GT (2 outlets to the motors) but doesn't come with the power button or charge port. If the existing power button is 14mm diameter or less, i'm in business. Will try and measure Matt G's on the next skate.
Andrew - a 10S 6P double decker battery pack overall with foam wrapping and inter-pack spacers etc. will be about 45mm deep x 150mm wide x 325mm long . Suggest that you build the battery pack first , then do a mock up with VESCs BMS and other bits before choosing enclosure . Cheers
