MAC 8T on 16S lipo ?

srtgumbee

100 µW
Joined
Feb 27, 2014
Messages
9
Location
New Zealand
HI all,

So I have worked out that a MAC 8T is needed for my goals of a commuter 40km/hr cruising most of the time, and 50km/hr + for short bursts so I can merge with 50km/hr traffic when needed (a couple of 500meter bursts at most). I will be using 26” wheels a 1.5” slick tyres. The commute is only 9km to work and 9km back, I have the option of charging at work and at home if needed. For this reason, I'm looking at using a small lipo pack (with high discharge rate) and I'm aware of the possible risks using lipo.

It seems a 12S pack might not quite get me upto 50km/hr and I need a higher voltage? Comments on this are welcome!

A 59.2V nominal 16S (4 x 4S 5000mah packs) is appealing as I can easily parallel up 2 x 8S packs for charging using a RC charger. Has anyone used the Mac 8T on such a voltage or higher? I would love to hear some comments regarding:

- Speed?
-Controller used? I'm looking at EM3ev 9fet high voltage controller, or should I be looking at the 12fet version and reducing the current in software.....eg 25 or 30amp limit as not to stress battery and/or motor
-Throttle response – Does it get twitchy at high voltages?
-Any other problems ?

Thanks Steve
 
I have an 8t with a 9fet. With the 110% setting my bike hits 65km/h with a fresh charge on a 14s pack. I regularly hit 60km/h after the initial charge has been used. All off road of course :twisted:

I don't find the throttle twitchy, but it did take some time to get used to, to take off smoothly. The biggest problem you will run in to, if you are messing with the controller settings is avoiding temptation to crank the phase amps. I messed about and had great results, (wheelies, wicked acceleration and other assorted hooliganisms). But I slipped the clutch and now it is very prone to disengaging at some very inopportune times. Order an extra clutch they are cheap if Paul throws it in with the kit to ship.

Paul has a great product but the clutch is the weak point. Start softly, don't hammer down from every stop and it will do you well.
 
10p14s drbass konion. 58.8 charge voltage
the trick is to make sure you get a program cable and make your highest speed setting 110%
 
emcee said:
I have an 8t with a 9fet. With the 110% setting my bike hits 65km/h with a fresh charge on a 14s pack. I regularly hit 60km/h after the initial charge has been used. All off road of course :twisted:

I don't find the throttle twitchy, but it did take some time to get used to, to take off smoothly. The biggest problem you will run in to, if you are messing with the controller settings is avoiding temptation to crank the phase amps. I messed about and had great results, (wheelies, wicked acceleration and other assorted hooliganisms). But I slipped the clutch and now it is very prone to disengaging at some very inopportune times. Order an extra clutch they are cheap if Paul throws it in with the kit to ship.

Paul has a great product but the clutch is the weak point. Start softly, don't hammer down from every stop and it will do you well.

What is your controller set at battery and phase? I'm going from 12s to 14 and I know it's gonna be differant.
Since I popped my 6 fet today it's a 12 fet now. the 6 fet was great for the last 2 years at 15 down to 12s with no problems, then it just quit. It appears I lost the 5 volt rail in it.

Dan
 
Thanks. Tried 42x90 and it is rough. will sofen it up a bit.

it sure gets to speed fast but rough or growing then smooths out.

I didn't have that withthe 6 fet. I know it took a while to get my other 12 fet 8t MAC to run smooth.
I have 3 8t MACs all in 26" with 12 or now 14s LiPo. Are real smooth on 6 fet and needed a lot of testing to get the 12 fet right.
Wish there was a way to read the controller specs, I know there isn't tho.

Dan
 
I give a little kick with the pedals at the start and roll the throttle on nice and smooth. Even with my slipped clutch the motor runs really good this way.
 
I built a bike today with the 8TMAC + 20R x 14S 11.7Ah triangle pack, there is massive amounts of spare space in the framebag which makes the installation an obsolute breeze.
didn't cut anything, just stuffed it into the framebag along with the controller. plug and play with beatuiful manifold of connections to the pack capable of 117A outputs!

-NB BMS limited to 40A continuous which is still HEAPS of grunt

at 30A wont sag and will last a very long time as they aren't being run nearly as hard as their 22P type cell (which is significantly cheaper but only good for 3C)

This configuration on an Aluminium commuter bike with a gates belt dive, 9 speed Alfine 200mm discs up front 160's on the rear ..... (fronts not set up yet but strategy is easy, just buy the two spacers and bigger disc all fits with the 160 anyway)

Goes like a freakin rocket. No speedo on the bike ATM but my hot-off charge my 350W MAC is good for 45km/hr and this thing feels like it accellerates just as
hard but the 350is all over at 45kph vs the 500/1000 which is still pulling hard at 50km/hr+, couldn't go any faster as was out of road!

The 22P would be adequate with the 9FET (~30A) (which is what we got with this kit) BUT i'm a big believer that a battery that can deliver more when run less hard does more than the difference in cycle life improvement anyway.

Result very VERY fast bike.
I'll report back as experience with it improves!
 
OK so Paul specifically says in programming instructions to avoid anything higher than 100% as he says "unsafe for the controller"

I'm running the 350W 16T mac and I'm fortunate enough that i'm old enough that if i throw a $100 controller it aint the end of the
world hence, tried it.......

Snapping footprints! 78A phase 27.5A battery 110% on the 6FET and it (controller or m0tor for that matter)doesn't appear to get hot.
(current factory is 70A so only 10% higher 27.5 vs 25A again just 10% but the bike now good for near on 55km/hr!

Yeikes, dont need to pedal as adrenalin pumps the heart rate up instead (still do though).

Does anyone here have any further experience with the 110% being an issue?
 
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