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By zen_racer
thats the high RPM version, nice pickup! i replied a bit on lipos on your other post so will just touch on the rest... for the controller i'd stick with the same type as offered in the combo kits , just for ease of hookup, maybe get a 48/60v dual voltage controller so you can play around with the lipo config and give yourself the option to overvolt. i think the controller should be under $50?

what type of chain are you using, dont know what is stock on the bladez. both my xtreme and rhino are using 8mm or T8F chain/sprockets. with a 64T wheel sprocket matched to a 10T motor sprocket running on 10-inch diameter wheels the speed calculator says top speed is slightly over 26MPH.

i ask what type of chain because the sprocket size options are different between 8mm and 25# chain...
By SpaceKaseJase
Thanks for the lipo help, brother. I think this motor's a pretty sweet deal. Did not notice it was high rpm, so bonus! Unfortunately, I don't know the chain or sprocket size. Still trying to look that info up. I know the sprocket is bigger than the Razor e300, so it's going to have some serious torque.
By SpaceKaseJase
Well, now I'm in the market for lipos. It's been awhile since I posted last because it took me forever to finally pony up the dough for the Boma 1500w 48v bldc. I'm thinking powering it up with two 6S packs which provide 44.4v. Trying to keep it around 10-12 A. Hobbyking has some 6S, 12A packs for around $110 each. Rating is 10C. This is what I'm not sure about. Do I want a lower C rating (like 10C) or a higher one (like 20-30C)? Thanks again for your patience.
By SpaceKaseJase
Don't have the controller yet. Not sure current rating other than 48v, 1500w, 5600 rpm. I believe you recommended this motor. Since it's going into such a small frame, it's going to be scary. I don't plan on WOT very often since there's no suspension. Might you know any more specs in this? I can't find any from Aliexpress.
User avatar
By zen_racer
based on similar motors offered by various sellers, i believe that motor is rated around 33-38a:

1500w divided by 48v = 31.25a

the math seems to support this estimation, so you'd want to make sure the controller is rated for at least that much, say 40a and up.

now when you look at the battery source, you'd want to take note of the continuous current rating and burst/peak current rating. in this case you'd want batts rated for 40a continuous. 40a burst/peak would be no good, that would mean the batts can only supply 40a for a few seconds.
By SpaceKaseJase
Well, if my research is correct, if each 6s cell is 12000 mah, and I multiply it by the constant discharge of 10c (20c peak), then divide by 1000, I get 120a. That seems excessive. Am I wrong?
User avatar
By zen_racer
the math is correct on your part, it's that some have suggested that the multistar ratings are inaccurate and/or over estimated by the manufacturer.

however, given that 120a is 3x your motor's rating there seems to be room for error. so if the multistars are only capable of half the advertised rating, there would still be enough amps to fully power your motor.
By SpaceKaseJase
That's good to know. So what I'm looking for are lipos that have continuous current rating that's greater than the output of the motor. Controller also needs to have a higher amp rating than the motor aswell, correct?
User avatar
By zen_racer
right, the motor is spec'd to run without issue at 35a under normal load conditions, but if you're going WOT uphill then the motor will pull more than 35a.

if the controller and/or batts can't supply enough amps to meet the current demands of the motor, then the motor will be underpowered and will feel sluggish.

like Rob and the mods used to say, more amps = more torque...
By SpaceKaseJase
Ok, sounds good. Once I get the lipos, I will def need advice on charging. Believe me, I've spent hours and hours researching all of this, so if I come to this forum, It's because I still haven't found the right info. Been doing this for months now, so help is beyond appreciated.
By SpaceKaseJase
So the cheapest lipo route for me (after hours and hours of research) seems to be these: ... p-20c.html

I was thinking grabbing 6 of them for 44.4v at 10a. That means I will need to connect two sets of 3 batts in series for 44.4v, then hook those two groups up in parallel for 10a. At 20c constant discharge, that leaves about 100a draw. Does that sound right? Need to create mockups of batts with exact dimesions to see if they will all fit in the body of the scooter.

Actually, I just realized that my math might be incorrect. Initially, I multiplied one cell (5000 mah) by discharge rate (20c), then divided by 1000 to get 100a draw. Since I will be paralleling batts to create 10.0 ah, then that would be 10000 mah times 20c discharge rate, divided by 1000 to get 200a. This is well over the required 35-38a motor output. So I should still be good at 20c right?
User avatar
By zen_racer
i've had good luck with zippy 30c lipos so i think that's a good choice, 20c will be fine for this application. i'm still using the zippys i bought 4 yrs ago for my pocket bike build... you can see pics towards the end of this thread:


another option which alot of members have had success with are the turnigy hardcases: ... ack-1.html

these go on sale very often, i've seen them for $20 which is hard to beat. i have 14 of them and use them in a few builds, had them for a couple year now and no complaints:


here's some food for thought - consider going 13s (48.1v nominal) instead of 12s (44.4v). also try to find out the LVC on whatever controller you might be looking at to match up to your motor.
Last edited by zen_racer on Fri Sep 21, 2018 12:33 am, edited 1 time in total.
User avatar
By zen_racer
SpaceKaseJase wrote: Thu Sep 20, 2018 1:39 pmThat means I will need to connect two sets of 3 batts in series for 44.4v, then hook those two groups up in parallel for 10a.
yes, that's pretty much what i've done. i connect 3 packs in series, connect another set of 3 pack in series, then use a parallel connection for both groups... top left of this pic shows the 2-way parallel connector (you can see the 3-way parallel connector in the previous reply)


here's how it looks with two packs in series, then paralleled to another two packs in series for a total of 22.2v 10Ah:

By SpaceKaseJase
Ok, great info. Going 13s makes sense, but not sure how much room I'm going to have in the chassis for the extra batt. also, how would I connect it to the rest of the batts?
Most 48v brushless controllers are pretty long, so again, I'll need to do some batt mockups to determine how much space I will have. In terms of LVC, what should I be looking for in a controller? Might you have any suggestions as to which controllers might work with my setup? I probably shouldn't worry about size. I have 3 of the same chassis, so I can always consider extending one of them for more space. My neighbor has an arc welder, so it would give me a chance to learn a new skill.
User avatar
By zen_racer
SpaceKaseJase wrote:how would I connect it to the rest of the batts?
the wiring would be the same, you're just replacing two 4s batts with two 5s: ... p-20c.html

so instead of 4-4-4 you'd series connect 4-4-5 to get 13s 5Ah, then parallel both groups to get 13s 10Ah. since those zippys all have the same C rating and capacity there would be no issues with that setup.

i do this often with my lipos so i can test various voltages using the same batts... i have four zippy 30c batts - one 5s, one 4s, one 3s, and one 2s - that i can mix & match since all batts have identical capacity (8000mAh). i do the same thing with my multistars...

as for BLDC controllers, i dont have much experience with them yet to provide a recommendation. i'd look for one that offers a high current rating (always nice to know you have more amps available if needed). the LVC is an important detail because you'll have an idea of how to set your lipo buzzers
By SpaceKaseJase
Ok perfect. I'll look into going 13s and see how I can get things to fit. Will also do more research on the controller. Probably won't have everything I need until after Christmas, so this is going to be a lengthy post. Thanks again for the help.
User avatar
By zen_racer
SpaceKaseJase wrote: Fri Sep 21, 2018 1:48 pmWill also do more research on the controller.
always glad to help!

forgot to mention this earlier - the controllers i have are lower end generic, so if they don't meet expectations my plan is to upgrade to either a Kelly or Golden Motor BAC-0501: ... p-504.html

based on positive reports here and other forums i believe either of these controllers would be an improvement over the ones on ebay and aliexpress. they dont cost much more, are programmable, and i think the customer support will be a better experience too
By SpaceKaseJase
So I made mockups of all 6 batts (four 4s and two 5s), and they will fit. Unfortunately (or not), the only way a controller will fit is on top of the batts. Is that not a good idea?
User avatar
By zen_racer
personally, i wouldnt have them in direct contact. though i'm comfortable using lipos and follow all the safety rules, it is a volatile chemistry and i've smoked a few controllers in the past so no way i'm risking damage to both batts and controller if one or the other gives out.

i'm looking at a similar situation with a different scooter build and thought about using a sheet of metal as both a heat sink and as a heat shield to protect the controller. in the meantime i've been using a lipo fire bag to isolate the battery pack in case of fire or explosion: ... afety+bags
User avatar
By zen_racer
it's not inexpensive but the specs, the form factor, programmability make the vesc an interesting option.

otoh only the motor and power connects are clear, what about the throttle and hall sensor wiring? this ESC seems primarily designed for use with RC-style sensorless motors.

on the BLDC motors we're using, there's a 5 terminal plug for the hall sensors... where would they connect on the vesc or can they be bypassed? how would you connect a 3-wire throttle, or would you need a potentiometer type of throttle?

if customer support can answer those questions it'd seem to be a nice match given the ratings.
By SpaceKaseJase
VESC are not much more $ than the Kelly controller, and tbh, I'd rather go with a cheap Chinese controller--if they were as small as the Kelly. You made some legitimate points to consider, zen. I did watch a video where a guy modified a servo tester to be used with a twist throttle and VESC, and I'm pretty sure it can handle sensored and sensorless motors. Rio uses one on his scooter. My biggest concern is the fact that VESC can only handle up to 12s. You suggested 13s for true 48v. Would 44v make that much of a difference in performance? Would that affect LVC?
User avatar
By zen_racer
awhile back i ordered a couple of these as a possible solution to using scooter throttles with an ESC but havent had a chance to test it: ... face-1-4v/

hot off the charger, a 1s lipo would be at 4.20v, so 12s at 50.2v would be hitting the max rating for the vesc. for peace of mind and long life for the controller i'd want the answers to come from the mfr, have them confirm if 50v is a hard limit and whether exceeding that would damage the components or is the focbox overbuilt to handle more.

re: performance, adding another 4v offers a modest increase in RPM which is reason enough for me to use it. another reason i use 13s is to increase the gap between max voltage and LVC.

when i run lipos i always use buzzers with the alarms set to trigger at 3.6v/cell. this is a higher LVC than the brushed controllers i'm using with these lipos, because i dont trust the accuracy of these cheap controllers to be the only thing keeping me from overdischarging and damaging my batt pack.

i believe the general recommendation is anywhere from 3.0 - 3.6v as the alarm cutoff for lipos but it tends to be a personal preference - do you want to err on the side of caution or try to squeeze out the most runtime from your lipos. with kids around i play it safe...
By SpaceKaseJase
Ok--it sounds like the Kelly is the best bet. The other controller you suggested (goldenmotor) doesn't have the size specs, so I can't tell if it will work or not. I'll have to find a way to get that info. Safe bet is 13s w/Kelly controller. thx again.
By SpaceKaseJase
So Hobbyking has a sweet deal on 6s, 16000 mah multistars. I figured the vesc you just found and two of those multistars (though only 44v) is still within my budget. Alternative setup would be the 13s zippys (1000mah) and kelly controller for the same price. I think the first setup is best with the extra ampherage. it comes to about $315 which is exactly what I have left to spend. All charging and misc accessories will have to be Christmas gifts. wdyt?
User avatar
By zen_racer
thats a tough decision. with that ebay vesc the numbers are nice but whether it holds up in a build is undetermined...not much info out there from actual users + product support from the seller may be lacking. having said that i may give it a try if the controller i have now dont pan out.

at the sale prices, i have yet to find any battery pack that offers the compact size, capacity, and power specs like the multistars. the turnigy hardcase packs when on sale are very close too and have better power ratings but the connections and recharging more complicated.
By SpaceKaseJase
So I ordered the two 6s 16000mah Multistars. Still debating on the controller, however. I like the programmability of the vesc, but the price of the cheaper Chinese controller also makes it a viable option. Size is no longer an issue since the two batts are too big to fit in the scooter. The solution (since I have 3 of the same chassis) is to cut two of the chassis in half, then weld the longer front half of one to the longer rear half of the other, thus lengthening the body. Should help with stability as well.

My next issue is what to use to charge the Multistars. Since 16a will last a long time, I do not need to quick charge it at all--maybe just overnight. Looking for an inexpensive balance charger and power supply to put on Christmas list--or a link to a good info source on balance charging so I can decide what best fits my needs. All the info I've come across is confusing.

Finally, I'd like to use a thumb throttle for my build. Can I just use any cheap one rated for 48v or are there specific ones for bldc's? Appreciate all your help and patience.
User avatar
By zen_racer
there are 2 types of throttles to choose from, the standard 3-wire and the 5k Ohm potentiometer type. its usually the controller that will determine which type you can use. i dont know that one is better than the other, but i prefer the 3-wire type because they're readily available and cheap.

if we look at the ratings for the multistar, they can be recharged up to 2C. for 16000mAh that works out to 32a!

a 6s pack would require at least 25.2v to fully balance charge. one advantage of lithium over SLA is the ability to fast charge. so if we wanted to fast charge, we'll need 32a x 25.2v = 806.4 watts at minimum!

we have to factor in efficiency losses from the charger and IR, so add another 20% ...806w x 120% = 967 watts.

re-do the math to charge at 1C, you'd still need a charger capable of 16a and rated for 500w. keep these numbers as a reference point and look at specs of the IMAX B6:

Max Charge: 50W
Charge Current Range: 0.1 ~ 6.0A
Li-ion / LiPoly Cells: 1 ~ 6

if you're charging a 6S pack, the most you'll get is less than 2a! 25.2v x 2a =50.4 watts which exceeds the wattage rating of that controller without having factored in efficiency losses.

if you parallel charge that's 32000mAh at less than 2a... it's going to take a very long time to fully balance charge both batts.

in general, you want a charger that has more than enough watts to accomodate your intended charge rate. and along with that you'll want a power supply that ideally has more power than the charger you'll hook up to it.
By SpaceKaseJase
How about this one? Charge current to to 25a, with capacity at 600w. I've read and researched, and I consider myself a fairly intelligent person (college educated), but I still have a hard time grasping the numbers. Based on your last post this should meet my needs (assuming I have the right power supply). Maybe I'm in over my head getting these huge batts... :? ... arger.html
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By zen_racer
that one seems nice, i was going to suggest it but see it has xt60 ports while your batts have xt90 plugs... not a big deal but you'll have to make or buy an adapter to hookup a paraboard. i dont think they make a xt90 paraboard that has xt60 power leads but i could be wrong.

i'll recommend this one too, HK puts them on sale often if you can wait...i have the older 300w version and no complaints: ... arger.html

for the power supply, i see that turnigy has some nice ones but i dont understand why they have a 240w ps if their charger is rated for 250w? for your usage though i dont think it's an issue at all

another option which is the route i took is to use a converted server power supply... this one is like mine, HP PSU which are well regarded: ... Swgd1awPQc

or you can save some money and get a lower powered PSU: ... 7675.l2562

just make sure your charger and power supply have built-in fans... these devices will be running a long time and heat kills.
User avatar
By zen_racer
also use the wattage formula to help decide on a charger:

W = V * A

a 6s pack is 25.2v, so if you plug in the charger's wattage rating you'll get an idea of how many amps will be available for recharging.

300w / 25.2a = 11.9a

so if you go with a 300w charger, you'd be able to charge near 10a (factoring in 20% efficiency loss).
By SpaceKaseJase
So excited! Found a way to earn an extra $160 to put towards scooter. With Christmas around the corner, I should have this thing finished by beginning of next year! Expensive sucker but gonna be so worth it! Thanks again for your help. Still researching charger and power supply, but I think I'm narrowing it down.
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By zen_racer
always nice to come up w extra funding for projects!

that combo is nice though maybe paying extra for the name, progressive is an established and reputable name in the RC industry. i actually have the 106B+. the turnigy reaktors are clones of the ichargers. i havent measured them against each other but in usage there isnt anything to distinguish one from the other...
By SpaceKaseJase
I think you just sold me on the Reaktor 250w. Read some reviews, and one guy mentioned he should've waited for Black Friday and gotten 2. Figured I can do the same and also get two 350w ps as well. Should be faster than parallel charging. Also got a couple hundred bucks more coming down the line. Still researching vesc, though I'm not finding anything with a limit beyond 12s. Waiting to hear back from someone who uses a vesc with 12s. Still considering the Kelly controller.
By SpaceKaseJase
You mentioned you used alarms on each battery to let you know if the volts are getting too low? You can program those, right? Also, I am looking for a good lcd display for my scooter--preferably one that can show the voltage of my batts. Do you recommend a certain brand or type?
User avatar
By zen_racer
yes i opted for the adjustable buzzers though they do sell buzzers that do not have this function, something to be aware of... since you have 4 batts i'd go w something like this and use the extra as a spare or quick checker: ... :rk:7:pf:0

i havent used any LCD displays so far, mostly because they cost a bit higher and i'm not going to use most of the functions the LCD versions offer. many e-bike builds use sensors to calculate wheel speed, to show regen current, distance, etc. i dont like complicating my builds by installing sensors, but if you want that info then LCD is the route to go.

i've settled on the throttles with built in LED voltage meter, since they're easy to wire up and i can use different battery voltages without having to switch out the throttle. for me, i'm fine with just seeing the voltage reading as that's really the only number i monitor when riding: ... st=ae803_4
By SpaceKaseJase
Ok, I have a similar voltage reader on my e300. Would be nice to somehow hook up an old smartphone to measure voltage.

I actually only have two batteries (6s, 16000mah x2) since they were on sale. They're still huge bricks, so need to modify chassis. debating if it's easier to lengthen it or widen it. So do you have the buzzers set up so you can read them? I was considering creating two cutouts on my deck and placing the buzzers in them so I can briefly look down and see voltage. Maybe overkill. So many ideas popping in my head... :idea:
User avatar
By zen_racer
the buzzers have audible alarms so there's really no need to have a visual on the readouts for each cell? for me they are the 2nd line of defense against over-discharge. so i primarily rely on the LED meter for the total voltage of the pack.

example - say your controller has LVC set at 42v. this is where the LED comes into play, providing a realtime voltage reading on the pack while idle and under load.

now if we do the math using that LVC of 42v, for 12s that work out to 3.5v per cell. if you dont want to run the pack down to that voltage, you can set the buzzers for 3.6v, - 3.7v so you know you have some juice left before the power cuts off.

continuing with that example, regardless of the alarm setting what you'll most likely find out is that the cells won't be balanced after a run. some cells may show considerably lower voltage than the others. that's where the buzzer comes in handy, to help identify imbalance.
By SpaceKaseJase
So I've worked extra the last few weekends and have landed about $460. So now what I need is the controller, charger/ps, 10awg wire, xt90 connectors, throttle, buzzers, and misc fabrication materials to mount the motor and modify the chassis. Looks like I'm going for the Kelly controller you suggested. Still waiting til Black Friday before getting charger(s) and ps.

Have a question about gearing, but will post in motors, drivetrain, and gearing forum.
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