MAC8T: Limiting via the controller or Cycle Analyst? both?

[efergy kb]

newbie question.
I am confirming how to setup the controller or CA correctly...

I got the MAC8T, 12fet 40A, 50V 12.3Ah Samsung Triangle Pack (Cell Type: INR18650-20R (11.7Ah, 580Whr) 14S6PSDITR)
From EM3's website it says the "The 20R Pack can easily delivery 40A continuous or more, but is limited to 40A Continuous by the BMS."

Does this mean on the controller you need to up the i) phase current = 56 and ii) rated current = 40.
Opening up to 40A allows the CA to control the output?
The factory default for the 3077 is i) phase = 56 and Rated current = 20.

And then from the CA you can further limit or get the max phase or rated current as per the max set by the controller?

 

[brumbrum]

The 20r battery is limited by the bms to 40a for longevity of use by the supplier, i believe it can put out 50a.

You need to up the phase current and max amp current on the controller by programming it. Probably 100amp phase and 40amp max current. Haveyou got the upgraded thicker phase wires on your mac? If not 100amp current maybe too much for the wires. Someone else will confirm this for you.

I would also like to know if this can be set alone usiNg the CA only and not the controller. , i doubt it. You will have to change bothe the controller settings and CA settings. Anyone?


On e you have set up the controller, you will be able to limit things by just adjusting the CA settings if you want lower max amps.

 

[ferret]

The CA can limit the battery current, but not the phase current.

 

[dogman dan]

Back up a bit. What do you want? More or less? You should have no need to reprogram the controller.

Thread title speaks of limiting, then there is talk of maximizing stuff.

The first thing limiting everything is your bms, which will prevent spikes big enough to damage the battery. That's before the controller of course.

Then the controller will have programmed limits. It may allow a spike for a blink, then it will ramp power down to it's max limit. It should be programmed now to not pop your bms limit all the time, so you should not have battery shutoffs constantly.

That controllers max limit can only be enabled by rolling back the throttle of course.

And, I think you can get a three speed switch on the EM3ev stuff, if you like to ride with even less power at times. Using a low power setting can be handy for slow hypermile riding, or just more fine throttle control when riding in a crowded place.

And of course, you can program various limits with the CA, and change them fairly easily. Handy if you wish to be "legal" at times.

 

[efergy kb]

Back up a bit. What do you want? More or less? You should have no need to reprogram the controller.

Thread title speaks of limiting, then there is talk of maximizing stuff.

The first thing limiting everything is your bms, which will prevent spikes big enough to damage the battery. That's before the controller of course.

Then the controller will have programmed limits. It may allow a spike for a blink, then it will ramp power down to it's max limit. It should be programmed now to not pop your bms limit all the time, so you should not have battery shutoffs constantly.

That controllers max limit can only be enabled by rolling back the throttle of course.

And, I think you can get a three speed switch on the EM3ev stuff, if you like to ride with even less power at times. Using a low power setting can be handy for slow hypermile riding, or just more fine throttle control when riding in a crowded place.

And of course, you can program various limits with the CA, and change them fairly easily. Handy if you wish to be "legal" at times.

Thanks all.. dogman. Makes perfect (logical) sense.
BMS --> Controller --> CA.

I got the 3 speed switch and upgrade phase cables... though the CA would make the 3speed almost redundant...
Not too sure of what these battery shutoffs you are referring to - care to elaborate?

So it looks like in either way... whatever point in the system (either BMS for Amps, Controller or CA for speeds and/or power output) will limit it anyway.

 

[dogman dan]

CA limiting not as easy to change on the fly as a three speed switch. So there is a place for it too.

I burned up my two speed controller recently, but I was enjoying a slow speed, forcing me to get better range. But with a flick of the switch, I could cross a dangerous busy road very quick. Then resume hypermile riding.

So nothing wrong with having it all.

 

[teklektik]

I am confirming how to setup the controller or CA correctly...
...
And then from the CA you can further limit or get the max phase or rated current as per the max set by the controller?

Unfortunately, you haven't indicated if you are buying a V2 or V3 CA - these are radically different products. The extra $30 to get a V3 is the biggest bang-for-the-buck upgrade you can buy for your bike - particularly for a gear motor rig.

You can get the Unofficial Guide here, but with this upgrade you get menu-driven matching of throttle and controller input/output voltages (no throttle dead zones), throttle ramping, integrated support of Current Throttle, automatic motor power rollback to prevent overheating, auto-cruise, multiple configuration setups or 'presets', and more. Certain features like the three speed switch to limit current are available in both models. The V2 supports Current Throttle as well but it is more of a custom wiring setup instead of a simple configurable mode as in the V3.

The V3 can be run in crippled legacy V2 mode if desired, but there are few reasons to discard so much functionality. Buy it - only $30 more - a particularly Good Plan since your upgraded motor already comes with an installed temp sensor...

...That's before the controller of course.

Then the controller will have programmed limits. It may allow a spike for a blink, then it will ramp power down to it's max limit.

Just a clarification - a XIe Chang controller may work this way - if programmed to do so. This is programming-dependent and is true only if the block time to 0.1s (or 0 if you are using custom programming software) to eliminate the initial period during which the programmed limiting is 'blocked' and the controller runs essentially without any current limiting at all. In general, Xie Chang controllers are set to run DD motors for 'block time' seconds off-the-line and are limited only by the motor and battery characteristics - the controller programmed limits are intentionally disabled to give the motor a kick in the pants to make up for the poor low end torque. MACs already have lots of low end torque and breakable gears/clutch and so the feature is disabled.

That controllers max limit can only be enabled by rolling back the throttle of course.

The throttle and the controller 3-speed switch are not directly related to the programmed controller current limits. In either case, operation of configured current limits is a distinctly different controller function.

And, I think you can get a three speed switch on the EM3ev stuff, if you like to ride with even less power at times.
...
CA limiting not as easy to change on the fly as a three speed switch.

Clearly neither the CA nor the controller max limits can be easily reprogrammed on the fly and all of the V2, V3, and controller setups support on-the-fly switching with a 3-speed switch. The question is whether you should use a controller or a CA 3-speed switch - the CA switch is arguably a better solution; it actually limits the configured available current unlike the controller switch which is simply a form of blind throttle limiting. Additionally, a controller 3-speed switch can muck up V3 operation, so - bad choice from the git-go if using a V3.

The controller throttle uses a fixed throttle-voltage-to-PWM-percentage control approach. However, using the V3 in Current Throttle mode makes the 'rated' motor current directly proportional to the throttle output voltage (with a good throttle that means 'percentage rotation'). This gives a much more familiar and controllable throttle feel at the cost of a bit of throttle lag. If you have a CA three-speed switch, the throttle effect is scaled according to the switch setting - so if you have a max CA current limit of 40A, a switch setting of 25%, and turn the throttle 33%, you will get exactly 40A x 25% x 33% = 3.3A. In the end, Current Throttle with a CA 3-speed switch can give much more predictable and refined throttle control than that afforded by the controller-only approach.

V3 throttle ramping allows you to soften the power application to the motor which is very useful to increase the lifetime of your gears and clutch.

In general, I think it makes more sense to view the CA and controller as a system rather than two separate devices - you are arguably in better shape leaving extra control functionality to the CA and running the controller in dumb mode - the controller becomes a simple 'power amp' for the CA. Program the controller max limits to protect the controller and battery and centralize all other limits/control in the CA where they are readily adjustable and operate in an integrated fashion.

Set the controller block time to 0.1s or 0s. EM3EV recommends a roughly 2:1 ratio for phase:rated current and I find that gives smooth/quiet motor operation at low speeds. Set these limits aggressively for strong midrange power. There are varying reports on running MACs with controller 'speed' settings above 100% but such settings are hard on the controller - leave it at 99%. Adjust the V3 ramping and AGain to soften the getaway to avoid dumping all the controller power into the clutch before the bike is moving along. Set the V3 max amps to the controller limit. Run with a CA 3-speed switch and Current Throttle. This should give you idiot-proof WOT getaways, a strong pull to max power, and good throttle control.

Get the MAC running out-of-box first then add and become familiar with the V3. Last - if you need to, tinker the controller programming - but that is a last - not first - step...

 

[izeman]

@teklektik: wow. this was by far the most complete and in-depth explanation of how controller, battery, motor and CA play together.
and to be honest: i'm happy that it matches my understanding already. good to see that i seem to have gotten it right already

ps. maybe you should add that post to the CA setup guide. it gives some valueable overview.

 

[efergy kb]

@teklektik solid advice; thank you.
Skimmed through the CA manual and i think your explanation in lay terms should be on the intro!