Programing The Controller

[Leslie]

Ok Id like to open a discussion relating to all the setting around the software weve been given

For instance.

I get the sense when you adjust your constant and MAX current setting in the controller this affects the total output of regen via a setting percentage for regen.

Reports saying that 100% regen is very powerful braking.  Way over the top, I ask 100% regen of what?

Possibly some of these settings are frequency modulated.  The constant current could be set by frequency of the gate drivers.  

The controllers can be indeed be magic if we are a little open on what could be a sweet spot. Can we find the sweet spot,

What are our best settings for our pack and regen to ensure maximum pack life and life of the whole kit.

Its pretty easy to undertand the faster your bike goes the faster the whole device will fail, this is where energy takes its toll. E_J=1/2mv

Besides this is the a correlation to the amps setting and regen percentage setting.  Are there good constant current settings our wheels will respond to.

Haveing said that, with this formula, to use, it cant hurt,


AH*C*100/Imax=% of regen.  

Based on a constant. We can charge most LI packs at .35C

If your pack is 12ah

AH=12ah

C=.35

And you set your max current in the software to 24 amps.

Imax=24

12*.35*100%/24=17.5%

Set the regen at 17.5%

And max at 24 amps.  Less chance batteries are being damaged.

Regardless of the nature of currnent managent performed by the software it must be PWM in nature.  So we just have an equasion that we can use to accertain what percentage of any given pack is safe by using the currnent settings as the variable.  

But in the end its how it feels, too much is too much on your BMS and cells.
    

[jensenff]

I look forward to some good thinking on this thread regarding REGEN. 
What is suitable level for the battery LIION?
I tried today to measure the AMPS with an AMP- tool.  It was not suitable for the job;  toooo big;  (0-400AMP on the low range on the instrument)  I will have to get (borrow) another instrument;


 

[Leslie]

I look forward to some good thinking on this thread regarding REGEN. 
What is suitable level for the battery LIION?
I tried today to measure the AMPS with an AMP- tool.  It was not suitable for the job;  toooo big;  (0-400AMP on the low range on the instrument)  I will have to get (borrow) another instrument;


 

It comes down to the point is regen too much and very imprortantly what type chemistry allows for high charge current.  Not all cells charge as well as they do discharge, and some tolerate fast charging well.

So we guestimate that GM packs do not want 10 amps belting at it cells huh?

Warning to all regen can be life limiting to many types of lithium batteries SLA's and NiMh.


Yes I figured the amps that came from regen could be robust.  And it could only be limited by the percentage in the software and that percentage was limited by the max amps setting on the controller.

The equasion is refreshing as it takes both battery size and charging maximum spec of the battery extracts its max charging amps 12ah*.35C=4.2 readies it for the percentage based on the users input of max amps, so in essence what ever happens the rider can only get 17.5% of max current which is 4.2 amps out of 24 amps.

For the GM 36v 12ah battery it could be more.

16ah*.35C*100%/24A=23.333% regen.  That looks pretty right too.

For 12 ah GM packs Set regen no higher than 17.5% 48v 12ah packs
For 16ah GM packs Set regen no higher than 23.3%






 

[Cornelius]

I think your constant at .35C are a bit low for the GM battery packs, according to this posting:

http://goldenmotor.com/SMF/index.php?topic=2095.msg10663#msg10663

Here, it's stated that max charge for the cells used in the GM batteries are 1.625C, but it's also mentioned 'Charging time 120min rated charge', which I take it to mean that 0.5C are the recommended charging amps.

Edit:
But for SLA etc. i'd agree that 0.35C are a good number.

[MonkeyMagic]

I have my regen set at 70% which I feel is MAX

Anything more I would have wheel lock or severe torque wear on my plates!

[Bikemad]

I figured the amps that came from regen could be robust.  And it could only be limited by the percentage in the software and that percentage was limited by the max amps setting on the controller.

Leslie,
My Magic Pie produces more Amps from regen that it actually consumes under full load!

These results were obtained while using a 7cell LiPo pack (25.9V 10Ah):
Maximum Power consumed = 20.66 Amps (584 Watts)
Maximum Generated Power = 23.35Amps (681.5Watts)

The regen is much less effective at a similar speed, when using a higher voltage battery:
Maximum Generated Power = 9.65Amps (525.8Watts) using a 14 cell LiPo pack (51.8V 5Ah).

I don't know how much difference it would make if I doubled the Ah rating of the pack as well as the voltage.

I have my regen set at 70% which I feel is MAX

Anything more I would have wheel lock or severe torque wear on my plates!

This is why variable regen would be so good, you would only use the amount of regen that you actually needed.
The wheel should never lock up completely as there is almost no braking force from the regen below 1-2mph, but the tyre may still slip in relation to the road surface, even though the wheel is still turning!

Alan
 

[Bikemad]

10. Maximum continuous charging current 6.5A
Maximum continuous discharging current 10A
Maximum pulse discharging current 40A

These packs are either 3p or 4p cells this makes a difference?  And is this per cell or for the whole pack?  The cells are 4ah so charging 1.65C isnt listed in the specs

Those specs are rather hard to understand.  If the charge rating was .5 per cell thats 2 amps per cell, 6A for three Parallel and 8A for four P.  Then one would hope the whole pack could output more than 10 amps.  So Wha?

The specs have us think that the GM cells can take 6.5 amps each, output 10 amps but the 4ah cells are rated at .65C?

But 6.5 amps for a 4ah cell that is 1.62c

Someone somewhere mixed up the cell rarting and pack rating, could be an expensive misprint.  Given the charger options GM offer I would vote .5C per amp hour and not 1.62C.

Leslie, these figures are definitely per cell!

My 5Ah LiPo cells are rated at 2C maximum for charging, so 1.65C for LiMn is probably about right.

The cells in the 12Ah pack should be able to withstand 19.8Amps of charging current and the 16Ah pack 26.4Amps, but the BMS may limit this to a lower figure. But if the BMS was to suddenly cut off during regen because the current was too high, what would happen to the controller? Does it have some form of built in protection to deal with the sudden voltage rise that would almost certainly occur?

My 10Ah LiPo pack has survived 23.35 Amps from regen without any obvious problems (it didn't explode and it still works fine ), but this was only for a very short time, not continuous.  A very steep long hill might be more of a problem though, as the Amps would be even higher at a faster speed, and they would also be produced for much longer with a steep enough hill.

I start to worry about those CA meters when I see readings like wheels output more power than putting in, it cant happen and if the wheel is overunity sell it on ebay for 10 billion EUD.

It can (and does) happen, but obviously not simultaneously!

The same wattmeter was used to measure both the current consumed and the regen current generated. The meter Source and Load connections were swapped around using home made gender changers on the Deans plugs and sockets.  All of the maximum current readings I have recorded so far vary by a maximum of 0.6Amp, so as far as I'm concerned, the regen current reading will be pretty accurate for a comparison to the power consumption figures, even if the wattmeter is not calibrated correctly. 

 
Alan
 

[jensenff]

I have measured amps to / from the pie with a clamp on ac/dc tester.  It is 0-100A 1,5%
Results are a bit suprising
Forward:  Max amp 15A  (checked this by setting max continous to 16A.  No noticable change in performance!)
Regen  80% :  16A
Regen  60% :  10A
Regen  40%:   8A
Regen  20%:   zero , nothing

It an all GM setup;  Magic Pie rear, internal controller, 36V16Ah GM battery.
(I also have to add the Hioki clamp on does not have a min/max register;  Hard to get an accurate reading....Reading given with no decimal)

[Leslie]

Thank you so very much.

My equation is almost working, I need to work out how to apply inefficiency to it.  I think.

You see the drift their I was expecting this.  Lots more regen on the high settings and none on the low settings,

16 amps regen? Their maybe some short circuit current applying more in rush current as the fets flip from power to regen mode.  


Can you do us one more test?  I think your first tests do show that the % of regen is effected by the software but I cant be sure,  We need to compklete the full round of tests.

I want you to leave your controller set to 16 amps max and test regen at 80% then move max and cont amps down under 10 amps with regen set at 80% and tell me is regen is effected by the software.  We can tell your regen is being effected by the hardware shunt.

I am placing bets your regen will decrease with lowered max amps and maybe constant amps in the software.

Can you get more than 16 amps from your MP? If not, Your controller is shunted by resistor wire..

If this is the case, Some calculations on your tests to give you some idea of the resistance you're running.

At 36v

41v/15A = 2.73 ohms.

Your whole system has 2.73 ohms resistance between middle point of your pack to the middle point of your motor.

At 48v

52v*2.73ohms= 19 amps.  



With a 60v pack you will get 23.4 amps.

Who said more volts don't get you more amps?

[Henkav]

I did do a test with my 36V 12 Ah battery.
When I put continuous to 10 A and Peak at 13 A, I could drive for 35 Km.
When I put continuous to 15 A and peak at 18 A, I could drive only 25 Km.
With 15 A I had more power but only a little more speed. ( 32 vs 31 Km/H )
The power result in going faster from 0 to 32 Km/H, and with riding against the wind was no problem.
Does any one else had tested with differend Currents?

Greetings, Henk

[o00scorpion00o]

I noticed my regen was based on the continuous current setting. I had it set to 50 % and it was throwing back 10 amps! The controller was Outputting 20 amps.

With the differences in power output of these controllers, regen might also be different. Something to think about!

[Magneto81]

So far I've had my bike set to 11 amps max and 30 amps max. I've noticed marginal improvement in torque and no improvement in speed with a max in both cases of 39kph (not very close to the 47 advertised...)
Power consumption at the higher rating is up an average of about 100 watts, so I'm going to set it back to 9 amps max to see what happens - hopefully I can gain some efficiency and I'm not too concerned about acceleration ( although hill climbing yes...).

I have a 48V, 12 AH SLA set of batteries powering it. All settings are set for 48V.

Anyone tried putting a 5th battery on these internet controllers for 60V? Anyone tried setting the controller at 24V with a 48V setup to see if they could trick the system into giving them more speed?

[MonkeyMagic]

The current MP has a max voltage input of 63v

You could use more batteries however, as you know the full charge of a 12v SLA battery can be upto ~15v so you will need to run a voltage limiter circuit (that can also handle the current) to ensure the voltage stays under 63v

When all of your batteries are fully charged, what voltage does it read on your meter?
You may be suprised to find that is somewhat close to 60v anyway

My GM 48v/12Ah battery has a full charge of around 54v



cheers

[Spacey]

I don't have the internal controller and run an external separate type of controller (40 amps), I take it there are no voltage restrictions on the actual motor? Just looking to get around 30mph so might add 12V to my 48v pack.

[Bikemad]

As long your controller can handle it and the motor does not get too hot, then there should not be a problem with the extra voltage.

Alan