How to "improve" a NiMH Vectrix battery before it becomes damaged

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Mik
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Joined: 12/11/2007
Points: 3727
Re: How to "improve" a NiMH Vectrix battery before it ...

Thanks The Laird!

That looks like an interesting design!

Could it possibly be built using an LM324 op-amp? If yes, then no 30V supply would be needed. I think a 12V DC supply will be needed for most designs (to power the impellers), so it would be convenient to use an op-amp that can "run" on 12V.

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The Laird
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Joined: 07/29/2009
Points: 257
Re: How to "improve" a NiMH Vectrix battery before it ...

Hi Mik,

The 081 op-amp will run very successfully on 12volts. The problem is that it's output voltage will range between about 3 volts and 9volts (with a 12volt supply). Op-amps do not (generally) have an output which reaches supply levels. There is then the difficulty of powering the output relay. The relay circuit as drawn will need a relay of 12volts and maybe a few resistor changes. The two 2.7Megohm resistors, in the comparator, would need to be replaced with 1.0 Megohm resistors.

The latching circuit will also need one or two resistor changes, but I would need some time to consider that side of things.

Other than the above, The circuit should run correctly. I will give it some further thought.

If you want any other variations, it is easier for me to look them over before you begin buying and building, might also be cheaper? :-)

Best wishes,

The Laird

Mik
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Points: 3727
Re: How to "improve" a NiMH Vectrix battery before it ...

The Laird wrote:

Hi Mik,

The 081 op-amp will run very successfully on 12volts. The problem is that it's output voltage will range between about 3 volts and 9volts (with a 12volt supply). Op-amps do not (generally) have an output which reaches supply levels. There is then the difficulty of powering the output relay. The relay circuit as drawn will need a relay of 12volts and maybe a few resistor changes. The two 2.7Megohm resistors, in the comparator, would need to be replaced with 1.0 Megohm resistors.

The latching circuit will also need one or two resistor changes, but I would need some time to consider that side of things.

Other than the above, The circuit should run correctly. I will give it some further thought.

If you want any other variations, it is easier for me to look them over before you begin buying and building, might also be cheaper? :-)

Best wishes,

The Laird

Thank you very much!

For now I still have to get the first circuit out of my system (the transistor IDeA). I am more than ever convinced that it is quite feasible and am getting close to have a final version (HAHA!) of the schematic. I already have all the parts for it and need to design my first ever PCB for it.
Once I have found out for myself if you are correct with your impression that it is impossible to do it that way, I'll have time to play with the op-amp version you suggest. An op-amp version was what I was expecting in the beginning, anyway, but now I have spent so much time on developing the transistor version that I want to know for certain if it can be made to work. No disrespect meant - and please continue to point out any potential or actual problems with it!

I now have 4 ASSR-1228 opto-darlingtons and will hopefully get around to breadboard test them all to find out if they behave themselves (when compared to each other).

And I will need a battery to connect any prototype to, that will have to come first, too. Next week is the 15-day self-discharge test date for the 10 replacement cells for the battery I recently analysed. Then I need to take apart and rebuild some of the modules. Connection of prototype to a battery is at least a couple of weeks away for me. When I put the battery together I will probably install a centre-tap (and maybe even 17-cell-segment tabs) just in case neither the 2 nor the 3 segment version of the IDeA works.

What I have done over the last few days is simulate power dissipation values for the transistors in the IDeA circuit, to check that they will never get anywhere near their maximum rating. It is looking good, unless I misunderstand something terribly (which is quite possible).

Here is a schematic showing what components will be on the actual PCB and which will be located elsewhere. That will hopefully make it clearer that this circuit is really not all that complicated.

IDeA Transistor 6.1 100 pixel

Below is the code (for http://www.falstad.com/circuit/ ) which I used to test the transistor power dissipation and other values of the circuit. It has all those parts stripped away that are not required to test the behaviour of the "Kernel" of the IDeA transistor circuit.
(For some reason the setting for some of the scope traces change when the code is saved. You need to the scope traces for the transistors to show "Vce vs Ic" - at least that's what I found useful to find the maximum power dissipation points.)

$ 1 0.0010 0.529449005047003 55 5.0 50
t 144 112 208 112 0 1 -50.90825899436074 0.40027835617753343 192.0
t 96 160 160 160 0 1 -0.1852687784498427 0.6152864429539496 192.0
t 144 208 208 208 0 -1 50.90826535172229 -0.40027686522625894 186.0
w 144 112 96 112 0
r 96 112 96 64 0 10000.0
r 96 240 96 288 0 10000.0
w 96 112 32 112 0
w 272 16 192 16 0
w 208 128 208 160 0
w 208 192 208 160 0
t 400 256 352 256 0 1 -50.90825899434254 0.4002783561870302 192.0
w 352 272 352 288 0
r 528 176 528 240 0 10000.0
t 400 320 352 320 0 -1 50.90826535173885 -0.4002768652172364 186.0
r 352 336 352 384 0 24000.0
t 464 288 432 288 0 1 -0.18526877845032175 0.6152864429539449 192.0
r 496 416 496 352 0 10000.0
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r 256 288 256 352 0 10000.0
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w 768 80 704 80 0
178 256 224 288 224 0 1 0.2 8.937019180341052E-7 0.25 1000000.0 7.5E-4 10.0
178 256 48 288 48 0 1 0.2 8.939046008808669E-7 0.25 1000000.0 7.5E-4 10.0
178 400 176 432 176 0 1 0.2 8.939046010230505E-7 0.25 1000000.0 7.5E-4 10.0
178 400 352 432 352 0 1 0.2 8.937019175939995E-7 0.25 1000000.0 7.5E-4 10.0
w 96 16 192 16 0
r 208 96 256 96 0 24000.0
w 256 80 256 64 0
w 352 240 352 224 0
r 352 224 400 224 0 24000.0
178 688 448 736 448 0 1 0.2 4.705882352941195E-5 0.25 1000000.0 0.0010 5000.0
w 16 48 16 224 0
x 695 510 736 513 0 12 Relay 1
w 736 464 736 480 0
r 736 480 784 480 0 1000.0
162 784 480 784 528 1 2.1024259 1.0 0.0 0.0
x 699 520 725 522 0 8 NC/NO
x 409 547 466 551 0 16 12V DC
x 282 93 314 96 0 12 SSR1
x 286 269 318 272 0 12 SSR2
x 431 223 463 226 0 12 SSR3
x 425 397 457 400 0 12 SSR4
w 96 240 96 208 0
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w 432 256 432 240 0
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w 256 144 256 160 0
w 256 160 208 160 0
w 432 320 496 320 0
w 496 320 496 352 0
w 496 352 528 352 0
w 528 240 480 240 0
w 352 16 368 16 0
w 368 80 368 16 0
w 640 64 624 64 0
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w 640 304 608 304 0
w 560 416 496 416 0
w 320 240 288 240 0
w 320 240 320 64 0
w 368 176 368 144 0
w 400 176 256 176 0
w 256 176 256 224 0
w 16 224 16 240 0
w 320 240 320 480 0
w 448 480 464 480 0
w 16 240 16 512 0
w 464 368 464 480 0
w 256 224 240 224 0
w 240 224 240 512 0
w 384 512 240 512 0
r 208 224 208 256 0 24000.0
w 256 256 208 256 0
x 470 546 516 550 0 16 SMPS
w 400 352 384 352 0
w 384 352 384 368 0
w 432 192 448 192 0
w 448 192 448 160 0
w 448 160 512 160 0
w 464 480 512 480 0
v 464 512 432 512 0 0 40.0 12.0 0.0 0.0 0.5
w 384 512 432 512 0
w 464 512 496 512 0
w 672 448 672 464 0
w 384 512 384 464 0
w 384 464 384 368 0
w 240 512 176 512 0
w 16 512 176 512 0
w 560 416 560 368 0
w 608 304 560 304 0
w 560 304 560 368 0
w 672 464 624 464 0
w 624 464 384 464 0
x 800 510 894 514 0 16 Warning LED
x 802 527 857 531 0 16 on dash
x 448 51 536 60 0 40 IDeA
x 401 66 581 69 0 12 (Imbalance Detection Apparatus)
x 428 81 564 84 0 12 Vectrix version - untested
x 29 347 210 351 0 14 SSR 1-4 = ASSR-1228-302E
w 576 432 224 432 0
w 224 432 224 288 0
w 96 288 224 288 0
w 224 288 256 288 0
w 576 432 576 224 0
x 26 416 191 420 0 14 12V SMPS: 4A continuous
x 28 372 172 376 0 14 PNP : BC856 hFE=186
x 28 395 172 399 0 14 NPN : BC846 hFE=192
w 512 160 592 160 0
w 592 160 592 480 0
w 512 480 592 480 0
w 624 64 592 64 0
w 592 64 592 128 0
w 416 128 400 128 0
w 400 80 368 80 0
w 400 80 400 128 0
x 715 314 743 317 0 10 Tab 1
x 709 236 743 239 0 10 Tab 35
x 714 155 748 158 0 10 Tab 69
x 707 74 747 77 0 10 Tab 103
w 608 528 784 528 0
w 688 496 688 512 0
w 688 512 672 512 0
w 672 512 608 512 0
d 672 512 672 480 1 0.805904783
w 688 480 672 480 0
w 672 480 592 480 0
w 672 448 688 448 0
w 608 512 608 528 0
v 768 304 768 272 0 0 40.0 51.33 0.0 0.0 0.5
v 768 224 768 192 0 0 40.0 51.33 0.0 0.0 0.5
v 768 144 768 112 0 0 40.0 51.33 0.0 0.0 0.5
w 96 112 96 128 0
w 96 128 128 128 0
w 128 192 96 192 0
w 96 192 96 208 0
w 32 208 96 208 0
174 32 112 64 144 0 1570.0 0.5 Resistance
174 32 176 64 208 0 5840.0 0.5 Resistance
w 64 128 64 160 0
w 64 192 64 160 0
174 528 288 496 320 0 5840.0 0.5 Resistance
174 528 240 496 272 0 1570.0 0.5 Resistance
w 528 320 528 352 0
w 496 304 496 288 0
w 496 288 496 256 0
w 496 288 464 288 0
x 713 45 1073 51 0 24 750uA to opto-darlingtons version
w 592 128 528 128 0
w 528 128 416 128 0
w 528 176 528 144 0
w 640 144 528 144 0
w 528 144 480 144 0
s 640 64 704 80 0 0 false
s 640 144 704 160 0 0 false
s 640 224 704 240 0 0 false
s 640 304 704 320 0 0 false
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w 160 128 160 144 0
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w 160 192 128 192 0
w 96 160 64 160 0
w 768 224 768 240 0
w 768 320 768 304 0
w 768 272 768 256 0
w 768 192 768 160 0
x 156 164 189 167 0 12 NPN3
x 209 122 245 125 0 12 NPN 1
x 327 261 360 264 0 12 NPN2
x 398 292 431 295 0 12 NPN4
x 203 219 235 222 0 12 PNP1
x 325 327 357 330 0 12 PNP2
w 608 512 496 512 0
o 1 64 6 99 0.9568131466127622 0.009568131466127623 0 -1
o 15 64 6 99 0.9568131466127622 0.009568131466127623 0 -1
o 0 64 6 99 61.23604138321678 0.002392032866531906 1 -1
o 2 64 6 99 65.46781215792284 0.005114672824837722 2 -1
o 10 64 6 99 69.99202319305638 0.00546812681195753 3 -1
o 13 64 6 99 69.99202319305638 0.002734063405978765 4 -1
o 159 64 0 34 80.0 0.00625 5 -1
o 160 64 0 34 80.0 0.00625 5 -1
o 161 64 0 34 80.0 0.00625 5 -1

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There is always a way if there is no other way!

Mik
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Points: 3727
Re: How to "improve" a NiMH Vectrix battery before it ...

Mik wrote:

....
...!

I now have 4 ASSR-1228 opto-darlingtons and will hopefully get around to breadboard test them all to find out if they behave themselves (when compared to each other).
...
......
...

Finally got around to test this: The ASSR opto-Darlingtons passed the test with flying colours!

I think they are ideally suited for this application (not that I really understand how they work, though....)!

I tested 4 ASSR-1228 opto-Darlingtons (that's enough to build 2 IDeA devices), using the 10V testing setup shown earlier in this thread.

The test question was this: How long does it take (with 0.76mA flowing through the ASSR-1228 input side parallel with a 1.2K resistor) for each individual (half-)ASSR-1228 to dimly light the test LED; and how long does it take until the test LED reaches maximum brightness?

The results:
at 760uA; dimly lit / fully lit (in seconds and all measured via visual inspection+wrist-watch by yours truly, a very partial observer...):
1A: 8s/15s
1B: 9s/15s
2A: 8s/15s
2B: 8s/15s
3A: 8s/15s
3B: 8s/15s
4A: 7.5s/14s
4B: 7.5s/14s

I'm very happy with that! Just like I expected. Maybe differences between these individual devices matter at 50kHz - but in the IDeA they are only expected to switch ON a couple of times per year.....and it does not matter much if it takes 1, 2 or 3 seconds longer!

I decided to do just one more comparison to confirm that they are closely "matched" for this application and tested ASSR-1228 4B and 4A again around the minimum threshold current to turn on the test LED.
The results: At 710uA the time to the first dim lighting of the test LED was (followed by eventual full lighting of the test-LED after 1-2min):
4a: 82s
4B: 75s

That result is also just fine with me! The amplification of small voltage imbalances in the Vectrix battery will be so strong around the cutoff point that these minuscule differences are meaningless. It all looks good to me for now!

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There is always a way if there is no other way!

Mik
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Points: 3727
Re: How to "improve" a NiMH Vectrix battery before it ...

The last schematic above did not include the 1.2k resistors that prevent the opto-darlingtons from switching to closed at very low currents.

I have made up custom symbols for the ASSR-1228 and included them in the new schematic below.

Other changes include how the ICL is operated and how the cooling impellers are being turned on and off. This is all to prevent them from remaining switched on when the Vectux is being switched off. During the next power-up the current draw through the DC/DC converter could be too high for the ICL resistor if the system and the impellers come on together.

The schematic below shows how I hope to disconnect the battery completely each time that the Vectux is being turned off. It will always go into "hibernation" with practically no standby current drain. And one will always have to press the "ICL" momentary switch (and have a working 9V cell in it) to re-awaken it.

IDeA 6.6

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mikemitbike
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Re: How to "improve" a NiMH Vectrix battery before it ...

Hi Mik, hi the Laird,
as I´m out off time because of my job, I´m not writing much these day´s,
but I have to thank both of you for your work on the circuits. Mik I´ll
try to catch up in december when I got more time! But I´ll make my circuit
a little bit smaller than you do, becaus I´ll use it for only for riding,
not for the deep discharge.

Greetings Mike

Mik
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Points: 3727
Re: How to "improve" a NiMH Vectrix battery before it ...

In the process of trying to design a PCB I have re-arranged the circuit somewhat.

Here is a schematic showing the same "kernel" but arranged differently. The peripheral parts have also changed a bit and are probably not final.

IDeA 7.5

Next is the simulation I used to check the schematic is correct:

IDeA 7.5b

And finally the code for the simulation applet:

$ 1 0.0010 0.529449005047003 55 5.0 50
t 240 128 304 128 0 1 -31.912614657462626 0.5697241042634721 192.0
t 192 176 256 176 0 1 -0.18515443923846855 0.6151787222655717 192.0
t 240 224 304 224 0 -1 50.71936672391769 -0.23060905724056813 186.0
w 240 128 192 128 0
r 128 128 128 80 0 10000.0
w 192 128 128 128 0
w 304 144 304 176 0
w 304 208 304 176 0
w 688 144 752 144 0
w 688 208 752 208 0
w 752 272 688 272 0
w 752 80 688 80 0
178 512 160 544 160 0 1 0.2 1.0086981205859048E-9 0.25 1000000.0 7.5E-4 10.0
178 512 320 544 320 0 1 0.2 2.4127439035570575E-9 0.25 1000000.0 7.5E-4 10.0
178 512 416 544 416 0 1 0.2 6.67405282710902E-4 0.25 1000000.0 7.5E-4 10.0
r 464 368 512 368 0 24000.0
178 656 320 704 320 0 1 0.2 0.002399880006089693 0.25 1000000.0 0.0010 5000.0
x 712 325 753 328 0 12 Relay 1
x 716 335 742 337 0 8 NC/NO
x 646 483 703 487 0 16 12V DC
w 240 224 192 224 0
w 352 176 304 176 0
v 688 448 656 448 0 0 40.0 12.0 0.0 0.0 0.5
x 733 410 827 414 0 16 Warning LED
x 738 435 793 439 0 16 on dash
x 823 87 911 96 0 40 IDeA
x 769 111 949 114 0 12 (Imbalance Detection Apparatus)
x 810 128 946 131 0 12 Vectrix version - untested
x 782 162 963 166 0 14 SSR 1-4 = ASSR-1228-302E
x 779 231 944 235 0 14 12V SMPS: 4A continuous
x 781 187 925 191 0 14 PNP : BC856 hFE=186
x 781 210 925 214 0 14 NPN : BC846 hFE=192
x 705 267 733 270 0 10 Tab 1
x 698 202 732 205 0 10 Tab 35
x 696 141 730 144 0 10 Tab 69
x 701 74 741 77 0 10 Tab 103
w 656 368 656 384 0
w 656 384 640 384 0
d 640 384 640 352 1 0.805904783
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v 752 192 752 160 0 0 40.0 50.95 0.0 0.0 0.5
v 752 144 752 112 0 0 40.0 51.33 0.0 0.0 0.5
w 192 128 192 144 0
w 192 144 224 144 0
w 224 208 192 208 0
w 192 208 192 224 0
w 128 224 192 224 0
174 128 128 160 160 0 1570.0 0.5 Resistance
174 128 192 160 224 0 5840.0 0.5 Resistance
w 160 144 160 176 0
w 160 208 160 176 0
s 624 64 688 80 0 0 false
s 624 128 688 144 0 0 false
s 624 192 688 208 0 0 false
s 624 256 688 272 0 0 false
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w 256 208 224 208 0
w 192 176 160 176 0
x 187 172 240 175 0 12 BC846(3)
x 231 124 284 127 0 12 BC846(1)
x 229 376 282 379 0 12 BC846(2)
x 183 428 236 431 0 12 BC846(4)
x 234 223 287 226 0 12 BC856(1)
x 234 478 287 481 0 12 BC856(2)
w 752 112 752 80 0
w 704 336 720 336 0
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t 272 384 304 384 0 1 -50.6974156964314 0.25252637358736507 100.0
t 272 480 304 480 0 -1 34.73981307552468 -0.5657860865863853 100.0
174 128 384 160 416 0 1570.0 0.5 Resistance
174 128 448 160 480 0 5840.0 0.5 Resistance
w 160 400 160 432 0
w 160 432 160 464 0
r 128 368 128 336 0 10000.0
r 128 528 128 496 0 10000.0
r 368 128 368 160 0 10000.0
r 464 112 512 112 0 24000.0
178 512 64 544 64 0 1 0.2 7.849921382031156E-4 0.25 1000000.0 7.5E-4 10.0
w 576 432 544 432 0
w 576 336 544 336 0
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w 576 176 576 80 0
w 576 80 544 80 0
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r 512 192 480 192 0 24000.0
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r 512 448 480 448 0 24000.0
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r 128 240 128 272 0 10000.0
w 128 240 128 224 0
w 128 272 192 272 0
w 128 384 128 368 0
w 128 496 128 480 0
r 368 448 368 480 0 10000.0
w 496 528 496 464 0
w 496 528 528 528 0
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w 752 256 752 272 0
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w 368 256 368 176 0
w 480 192 432 192 0
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w 448 528 368 528 0
w 368 528 352 528 0
w 464 368 304 368 0
w 752 208 752 192 0
w 752 160 752 144 0
w 368 448 368 432 0
w 368 496 368 480 0
w 464 32 624 32 0
w 624 32 624 64 0
w 608 128 624 128 0
w 592 256 592 128 0
w 592 128 608 128 0
w 608 192 624 192 0
w 608 192 608 272 0
w 576 432 576 384 0
w 656 448 608 448 0
w 608 432 608 320 0
w 560 320 608 320 0
w 608 320 656 320 0
w 640 352 656 352 0
w 688 432 688 384 0
w 688 384 656 384 0
w 576 336 640 336 0
w 640 336 640 352 0
w 576 384 576 336 0
162 720 400 720 432 1 2.1024259 1.0 0.0 0.0
r 720 352 720 384 0 1000.0
w 720 448 688 448 0
w 720 336 720 352 0
w 720 384 720 400 0
w 464 448 480 448 0
w 464 448 464 496 0
w 464 496 320 496 0
w 352 336 432 336 0
w 352 176 368 176 0
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w 688 432 688 448 0
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w 608 272 496 272 0
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w 480 272 496 272 0
w 512 208 480 208 0
w 496 336 496 256 0
w 592 256 496 256 0
w 496 256 432 256 0
w 368 272 368 432 0
x 468 139 547 142 0 12 ASSR-1228(1)
x 463 395 542 398 0 12 ASSR-1228(2)
x 516 95 521 97 0 9 1
x 519 189 524 191 0 9 3
x 516 108 521 110 0 9 2
x 519 206 524 208 0 9 4
x 549 174 554 176 0 9 5
x 548 159 553 161 0 9 6
x 550 79 555 81 0 9 7
x 553 62 558 64 0 9 8
x 518 349 523 351 0 9 1
x 517 366 522 368 0 9 2
x 518 463 523 465 0 9 4
x 520 447 525 449 0 9 3
x 549 429 554 431 0 9 5
x 553 317 558 319 0 9 8
x 551 335 556 337 0 9 7
x 550 414 555 416 0 9 6
w 528 528 592 528 0
w 592 528 592 304 0
w 592 304 624 304 0
w 624 304 624 256 0
w 128 80 368 80 0
w 368 80 464 80 0
w 464 112 304 112 0
w 368 176 368 160 0
w 368 128 368 80 0
o 39 64 0 34 80.0 0.00625 0 -1
o 40 64 0 34 80.0 0.00625 0 -1
o 41 64 0 34 160.0 0.00625 0 -1

__________________

This information may be used entirely at your own risk.

There is always a way if there is no other way!

7circle
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Joined: 01/04/2008
Points: 66
Re: How to "improve" a NiMH Vectrix battery before it ...

Your having some great success with the FALSTAD simulator.

It's a great a quick tool to test and share circuits.

I like your LED indicator Find, I haven't worked how to find that one yet.

I have had made some circuits it could find a solution to after 5000 iterations.
But if I moved the ground point it worked.

A current sensors that show the current in the circuit. (Found it just edit the wire and show current and/or voltage ... too easy)
Or just as good a two point voltage meter you can then use with at shunt to show current.

The version is up to 1.5m (your pictures show 1.5k)

And I noticed it has a new export feature that allows a URL link to be made with all the Circuit details hidden into the URL Link
But it doesn't (yet Allow you to copy this into the import window and build the circuit.
You need to use the Browser URL entry.
Also it still comes up in Emailed posts.

Test Info : Your Circuit as a link - Open in New Tab to launch Simulator

Mik
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Joined: 12/11/2007
Points: 3727
Re: How to "improve" a NiMH Vectrix battery before it ...

7circle wrote:

...
I like your LED indicator Find, I haven't worked how to find that one yet.

That's because it does not exist, yet!

I'll have to work out how you created that nifty link to the working circuit - very nice! No time right now...

__________________

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Mik
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Re: How to "improve" a NiMH Vectrix battery before it ...

Playing around with ExpressPCB now, here is a preliminary result:

Photobucket

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Mik
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Re: How to "improve" a NiMH Vectrix battery before it ...

7circle wrote:

Your having some great success with the FALSTAD simulator.

It's a great a quick tool to test and share circuits.

...
...
...

Yes, it is a nice tool....it even helped me to "invent" something by myself. All "grown on my own dung-heap", so to say, and therefore possibly complete hogwash. If not, then it is probably a well known circuit (and/or an long outdated one...)!

Anyway, here it is:

http://www.falstad.com/circuit/#%24+1+0.0010+9.78399845368213+42+5.0+50%0A178+672+368+672+416+0+1+0.2+8.881784197001253E-18+0.05...

It's purpose is to delay the closing of a contactor for a few seconds, to allow the pre-charge resistors (ICL) to complete charging the capacitors at a controlled current rate. I'll try it out for real as soon as the capacitor arrives.

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Mik
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Re: How to "improve" a NiMH Vectrix battery before it ...

Here is a little improvement to the contactor-delay circuit:
http://www.falstad.com/circuit/#%24+1+0.0010+9.78399845368213+42+5.0+50%0A178+672+368+672+416+0+1+0.2+6.1235740190905994E-18+0.0...

There is now a resistor in parallel with the capacitor. This allows the cap to discharge so that the delay function resets itself relatively quickly. Without this, there could be problems if the Vectux is turned off and then on again very soon after.

..

And here the schematic showing how it fits into the IDeA:

IDeA 8.4

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Mik
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Re: How to "improve" a NiMH Vectrix battery before it ...

And here the latest PCB design for the IDeA:

IDeA PCB 3.5

It probably still has errors in it and needs thorough checking before I make one (or have one made).

If anyone wants to help with double-checking the PCB design, send me a PM and I can send the ExpressPCB file to make it easier.

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Re: How to "improve" a NiMH Vectrix battery before it ...

Does anyone have a good idea how to integrate a cutoff-voltage for the DC/DC converter?

The DVC75 which I intend to use http://deutronic.com/fahrzeugwandler/75-watt-pot-getr_data_de.pdf works with input voltages from 56V-154VDC.

It is unlikely that no imbalance will occur when the battery voltage drops to around 0.9V/cell= 91.8V and this will turn the DC/DC converter off when in "Automated Deep Discharge" mode. But I would nevertheless like to have an independent safeguard against further discharge that turns it all off at about 92V.

Any ideas how to do this?

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mikemitbike
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Re: How to "improve" a NiMH Vectrix battery before it ...

Hi Mik, did you ask Deutronic directly if it is possible to change the settings that the converter cut off itself at 92V?
Another solution would be a voltage divider and a schmitt trigger which should be easily adapted to work with the Vectrix´
voltages.
The left circuit has two status LED (green above and red below a selected voltage)
The right one has only a red LED lighting up below a selected voltage.

The second circuit with a better drawing.

They would need a voltage devider or other resistorsetings but would work. Unfortunately I´m still running out of time with my
other project (Testing the GP 78Ah NiMh Blocks for my Fiat PandeE.
Here is one link how to calculate voltage dividers: Voltagedivider-calculatro
We would need the "Spannungsteiler-Rechner No. 2" RL is resistance of the schmitt trigger circuit (which must be measured and/
or calculated first)

Mik to check up the latest shemata, some more Info would be helpful as I had problems to recognize each of the Pins 1-22 and
still not sure what the blocks on the left side of the PCB board ar for (The poti´s (adj. resistor) and the transistors of
the "kernel"-circuit?

greeetings Mike

Mik
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Re: How to "improve" a NiMH Vectrix battery before it ...

mikemitbike wrote:

Hi Mik, did you ask Deutronic directly if it is possible to change the settings that the converter cut off itself at 92V?

I did, but they would need at least 50-200 orders to make it worth their while.

Quote:

Another solution would be a voltage divider and a schmitt trigger which should be easily adapted to work with the Vectrix´
voltages.
The left circuit has two status LED (green above and red below a selected voltage)
The right one has only a red LED lighting up below a selected voltage.

I have not been able to get a simulation of that circuit happening, but have not tried very hard.

Quote:

Mik to check up the latest shemata, some more Info would be helpful as I had problems to recognize each of the Pins 1-22 and
still not sure what the blocks on the left side of the PCB board ar for (The poti´s (adj. resistor) and the transistors of
the "kernel"-circuit?

I'm working on it. Need to make "custom components" to accurately represent the SMT transistors I have, as well as other components.

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Re: How to "improve" a NiMH Vectrix battery before it ...

Hi Mik,
did you get any further with the circuit? I spend a lot of time with the 78Ah NiMH´s
for my Panda, so I got stuck a bit. Finaly I decidet to make the circuit only for
showing the inbalance during the ride. To equalize the cells will be very tricky.
below you see one module with 10 cells at two dischargetests.

The black test was stopped at 50 Ah because one cell was empty. The other nine where
discharged in a seperate test which showed they had 20 Ah left. After a full charge
I discharged the 10 cells and they had become equal (red test).
on other tests I had cells with only 50% left when the other 9 cells had 90% charge.
To balance such cells would mean to overcharge between 30 and 50% of the capacity.
So I´m looking for a possibility for single cell charging which is small enought to
be left in the battery and cheap enough to be build. Something like the cutoff-modules
attached on Lifpo4-cells. In this case not for chargecutoff but to charge each cell with
0,1-0,5 A to a certain voltage level...

Greetings Mike

Mik
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Re: How to "improve" a NiMH Vectrix battery before it ...

mikemitbike wrote:

Hi Mik,
did you get any further with the circuit? I spend a lot of time

with the 78Ah NiMH´s
for my Panda, so I got stuck a bit. Finaly I decidet to make the

circuit only for
showing the inbalance during the ride.

I have been busy with my newly acquired Prius Scanner, fixing

mine and other people's NHW10's. The Vectux is taking a back seat at the

moment. All I have managed to do is put it on the main stand and

finally move it under cover. Am getting the Bathot + temperature

+ battery warning telltale due to false temp sensor readings.

Will have to take off the M-BMS and see if the problem

disappears. It's a little moist here at the moment....and if it

occasionally stops raining, it quickly gets too hot to ride. I can't be bothered to take the thing apart again!

But the DC/DC converter for the IDeA is in the mail and the IDeA keeps on

fermenting on low heat in the back of my mind.
.

The "Special Freddy NHW10 EQ Charger 15.0" is going to be completed

as soon as the last part arrives, a 6VDC 4PDT relay. The charger

itself is ready and working quite reliably, but the "Battery

Side" part needs to be installed so that I can do a Prius EQ

charge without any hassle, like removing the back seat, opening

the battery, exposing dangerous parts etc etc.
Photobucket

With the Techno Scanner I can now measure all sorts of things in

real time, like 20 battery module voltages, current, pack

voltage, 9 different temperatures in the pack, delta-SOC, SOC and

anything else that was designed into the car. Hundreds of items,

most of them displayed only in Japanese. A great toy and great

insights into a good NiMH BMS! And it is so much more comfortable

to drive an airconditioned Prius with roof over my head than a

Vectrix. So it may be quite a while before I get to work on it

again.
.
.

Quote:

To equalize the cells will be very tricky.
below you see one module with 10 cells at two dischargetests.

The black test was stopped at 50 Ah because one cell was empty.

The other nine where
discharged in a seperate test which showed they had 20 Ah left.

After a full charge
I discharged the 10 cells and they had become equal (red test).
on other tests I had cells with only 50% left when the other 9

cells had 90% charge.
To balance such cells would mean to overcharge between 30 and 50%

of the capacity.
So I´m looking for a possibility for single cell charging which

is small enought to
be left in the battery and cheap enough to be build. Something

like the cutoff-modules
attached on Lifpo4-cells. In this case not for chargecutoff but

to charge each cell with
0,1-0,5 A to a certain voltage level...

Greetings Mike

Equalising the cells in the battery will be tricky, indeed. I

would try to replace the worst ones, and concentrate the

moderately damaged ones into one easily accessible part of the

battery. In the module shown above it is an increased self-

discharge rate in the weak cell that is causing the trouble.

If it is not too severe, and if you do not need the entire

battery capacity, it might possible to use the battery "as is". If

you can limit the DOD to 50% of the battery capacity, the weak

cell would end up operating between 10%SOC and 60%SOC while the

best cells operate between 40%SOC and 90%SOC. That would keep all

cells reasonably happy - the SDC is much higher at higher SOC, so

the imbalance might stabilise. The imbalance detection circuit

could warn you when a cell eventually reverses. Depending on the

overall battery SOC at which this occurs you could then do a

partial EQ charge, to bring the weakest cells back to within 30%

delta-SOC of the better cells. It would be really easy to do a
"no damage EQ charge" if the weak cells are arrenged into a
coninuous sub-string anywhere in the battery that is easy to get to,
or that has permanent tab cables installed. You just top up
the weaker cells once the imbalance detector goes off,
or better, just before it goes off! That would inflict little damage
upon the good cells if done slowly and with active cooling.

It all depends on if you can live with using only half

your battery capacity most of the time.

How many cells are in your Panda?
.
.

Oh, there is an important question I have about the IDeA:

What level of vibration resistance and shock resistance would be

appropriate for the relays used in a Vectrix scooter?

The only relay in the current IDeA design which could cause a

critical malfunction (due to undesired opening while driving over

bumps) would be RLY2.

RLY2 is normally open; when it's coil is energised with 12V DC

(by turning the key ON or if the "Deep Discharge/Timer Switch" is

closed after powering up) then it will connect the 12.5VDC/DC

converter to the main battery. The DC/DC converter then powers

the Contactor and closes the 102s battery string. If the relay
were to open due to vibration/bumps/shock, the DC/DC converter would
stop providing 12V to the contactor and the power supply would get
disrupted suddenly, causing loss of motor power while in traffic.

Some relays mention in their data sheets how many "g" they can handle,
sometimes for energised vs. non-energised state etc.

What is the appropriate shock and vibration rating to be used for a critically important electric scooter part?

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Re: How to "improve" a NiMH Vectrix battery before it ...

Mik wrote:

It's a little moist here at the moment....and if it
occasionally stops raining, it quickly gets too hot to ride. I can't be bothered to take the thing apart again!
But the DC/DC converter for the IDeA is in the mail and the IDeA keeps on
fermenting on low heat in the back of my mind.

I hope you are not in the area with the heavy raining and the flood?!
I switched most energy to the Panda-Project, as the car can be used
much earlier than the scooter and has far less problems with moisture
as the batteries/chargers are stored where the backseat and trunk are.

curently there are 14x6V 110Ah lead-acid(gel) batteries used. As they
are rather old I can only use about 50 AH giving me a range between 25
and 35 km. So I looked for theese used NiMH modules... each pair of
the batteries is attached as 12 volt module to a simple IU charger.
I plan to replace them with the NiMHs.

Quote:

...would try to replace the worst ones...
...It all depends on if you can live with using only half
your battery capacity most of the time...

That is no option for me. The modules should be able to deliver
between 65 and 70 AH if needed. normaly I´ll use only 50% of the
capacity. I´ll try to find out how fast they loose their charge
(the cells with faster selfdischarge are marked). And with another
version of the IDEA (with temp-monitoring) I should be able to
see if one module needs a refresh. There will be a problem if I
have to change a cell, because the black plastic-spacers between
the cells are old and weak and begin to brake, so it will tricky
to change a cell without opening the metal-ribons.

Quote:

...How many cells are in your Panda?...

Now 14 Lead Acid, 84V Systemvoltage 50-60 AH usable charge.
Planed 14 NiMH modules with 84V and 130-140 AH. 7 segments
with 12 volt because of the 7-charger-infrastructure. This
means that either there will be 2 batteries with 7 modules
each and 2x 7 chargers disconneted during charge or one battery
with 7x two modules parallel connected. With my charging current
it would be able to charge them parrallel (10 hour to full) but
it will still need a good thermal sensoring. That would be a
better solution than to have 14 chargers. I don´t plan to
install a 84v Charger, because curent infrastructure it´s
easier to do EQ charges.

Quote:

...Oh, there is an important question I have about the IDeA:

What level of vibration resistance and shock resistance would be

appropriate for the relays used in a Vectrix scooter?
What is the appropriate shock and vibration rating to be used for a critically important electric scooter part?

I´m sorry I´ve no idea. Is it possible to us only solidstate-relais
instead of electro-mechanic ones? would a thyristor be a solition
for the connection between MC and battery?

gretings Mike

Frolle
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Points: 46
Re: How to "improve" a NiMH Vectrix battery before it ...

Hi.
What do you guys think about using a few of those "Lipo Battery Low Voltage LED Tester Meter 1S-8S Buzzer Alarm Indicator" sold on Ebay 3 USD including shipment?

lipo.jpg

At the moment my plan is to buy six of those (search for "1-8s" on Ebay) to monitor all cells, three by three.

(a cut and paste)
Product Feature:
Use for 1-8s Lipl/Li-ion/LiMn/Li-Fe
Voltage detection pricision: 0.01V
Unit voltage display range: 0.5V-4.5V
Total voltage display range: 0.5V-36V
1S test mode voltage range: 4v-15v
Low voltage alarm mode for 2-8S
Alarm set value range: OFF-2.7V-3.8V
When the voltage is below the set value,it will buzzer with red LED light,pre-set value 3.3V.
Push key which can change the voltage settings and save.

I plan to use three Ethernet patch-cables for each battery-box because it's cheap and available.
Those modules fits in to a old IDE hard drive cable.

Together with 30pcs of ring terminals and 30pcs of 3A car fuses (spade fuses?) it would be possible to find week cells both visual and audibly during riding.

Any thoughts ?

This solution would cost about 50 USD and some work effort.

antiscab
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Points: 1603
Re: How to "improve" a NiMH Vectrix battery before it ...

Frolle wrote:

I plan to use three Ethernet patch-cables for each battery-box because it's cheap and available.
Those modules fits in to a old IDE hard drive cable.

Together with 30pcs of ring terminals and 30pcs of 3A car fuses (spade fuses?) it would be possible to find week cells both visual and audibly during riding.

be aware the car fuses are generally only rated up to 32vdc.
above this, when the fuse blows an arc is formed, resulting in the fuse burning as well as the circuit not being broken

given the small wire you are using, that may not be an issue, as when the insulation burns away under a fault condition, the copper oxidizes rapidly leading to high resistance.

I would probably use a lower fuse current if using car fuses, more like 0.5A

other than that, not a bad idea

Matt

__________________

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst replacement TC Charger
conversion
Spent so far: $5800 + $7000 + $1720 + $960 + $320 + $720 + $140 + $600
Cost to do it again: $2500 + $5600 + $1720 + $960 + $320 + $720 + $140 + $600
Cost for a Petrol bike:$6000 + + $1440 + $6000 + $800 + $1400 + $3200 servicing
Total spent: $17260
Total to do again: $12560
Total to have used a petrol bike: $18840
Total distance travelled so far: 79'120km

Mik
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Re: How to "improve" a NiMH Vectrix battery before it ...

Ahem.....I never got around to build the complex IDeA (Imbalance Detector Apparatus) and by now I am having a hard time even understanding the schematics.

However, the principle of splitting the pack into three equal segments is valid and proven on the workbench in a few experiments with Vectrix NiMH batteries.

The tricky bit is related to comparing three voltages and then making decisions based on the voltage comparison and then start actions based on the decisions. So I decided to use my brain for that purpose instead of an electronic gizmo.

All the IDeA needs is three voltmeters on the instrument panel and a switch to turn them all off when not needed, to stop the <7mA power drain caused by them. All water proof, of course. And a pair of eyes and a brain. It will not be fully automatic, but very simple and effective.

It will cost about AU180.- for the voltmeters and will allow me to see if there is a reversing cell anywhere in the battery during riding, charging or discharging on the centre stand with the cooling impellers and/or MC and/or headlights on.

http://www.murata-ps.com/data/meters/dmr20-10-dcm.pdf

Does that make sense?

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