Here are the results of the first Half-pack (HP) of battery NHW10-02 tested with the Ampeasel.
General AMPEASEL test procedure:
Reduce current or terminate test at any time if the curve looks like the stick is not coping
1) Turn on recorder (PoScope)
2) Start at full load, ~ 100A
3) Switch to ~30A after 1min of discharging.
4) Switch off when 5.5V cutoff voltage is reached.
5) Measure resistance of Temp Sensor Strips with max recording for each stick (results not shown, they were very unspectacular! The best sticks show a rise from 1 Ohm to 1.8 or 2.0 Ohm; poor sticks show no rise because less energy is dispensed in the discharge)
6) Wait for the voltage to rebound and flatten out (some of the most interesting details can be in that part of the curve!)
This battery had been removed from a Prius 1-2 years before I got it (about a year ago). It was "charged up" occasionally with the booster charger included in the NHW10 Prius (by the previous owner). As far as I know, this does not fully charge the battery, only brings it up to enough SOC to kick the ICE over. I let it sit for 6months or so, uncharged.
In mid December 2009 I opened the battery up and measured voltages:
Entire open : 273.3V
HP1 open: 134.8V
HP2 open: 138.4V
I charged the battery very slowly (5 days) just once
(using Universal Freddy, a charger similar to Special Freddy, but it has 4 different switch-able motor run capacitors to make current adjustable).
This was in preparation for buying my first Prius NHW10 (the blue one) off ebay. I won it, dropped the battery into the car and drove it until early March 2010 without apparent problems. The warning triangle was permanently on - it stays on even if the battery is perfectly good. It can only be reset with a Toyota S2000 scan tool.
Then, in early March I got some indications that the car was trying to charge the battery by revving the ICE slightly higher than usually, and then a single "turtle" (a turtle shaped LED on the dash, meaning "Go Slow" or something like that).
I repeated the EQ charge, this time in the car and over 2 days, which fixed it all back to working well. Another week later I repeated the EQ charge to test the wiring harness I had installed by then, adding in a variac to boost the voltage. It all worked well.
I drove the blue Prius for another week or so (without any apparent problems), and then I parked it in the sun for about 3 to 4 weeks. The first week or so without a cover, the last two weeks with a white car cover. All of this in Australian Summer heat conditions.... I had just bought another two NHW10 Prii and was busy with them, and with analysing and repairing the battery that had come with the blue car, the one I called "Dead as a Dodo?? Dying Swan or Phoenix?" battery mentioned above. Once I had restored the original battery by replacing a single bad stick in it, I put it back into the blue car; no more warning triangle since then (due to the original B-ECU installed with it - it does not have the warning triangle stored!).
It was on April 24th that I removed the NHW10-02 battery from the blue car and started a stick-level capacity test on April 26th, named the CBAIII Test 1
below; done at 12A to 5.4V cutoff level.
The results were all over the place! They do not correlate with the later test results, except for the worst stick of them all - that one was bad in all three tests (but only HP1 finished testing so far).
Then I charged both HP's once
on the bench and let them sit for three weeks, before the CBAIII Test 2
(also at 12A to 5.4V cutoff).
Because the results were so different from the first test, I cycled the HP's 5 times on the bench (whilst improving the method for detecting a single reversing cell) and then let HP1 sit for 2 weeks in the cool garage to self-discharge. HP2 is up for the Ampeasel test next, in a few days time when it has also rested 2 weeks.
The results of the first CBAIII capacity test (after 3-4 weeks of standing in the car in the heat) are given below together with the results of the second self-discharge test with the CBA III and with the graph showing the result of the third (Ampeasel) self-discharge test done yesterday. This helps to show if the high current Ampeasel test is actually helping, and if the 5 x cycling has helped!
Red curve: Voltage in V
Blue curve: Current in A x 20
X-axis: time in h:min:sec:msec
The sticks were not tested in the Ampeasel test in the order shown below. Instead, I started at the top of the pack to reduce the heating up of untested sticks from the discharging sticks below them.
Stick 1 = negative end of the pack.
Stick 20 = positive end of the pack.
CBAIII test 1: 1.956Ah; good curve.
CBAIII test 2: 4.642Ah, good curve
AMPEASEL test: A good one:
CBAIII test 1: 1.876Ah, good curve.
CBAIII test 2: 4.519Ah, good curve.
AMPEASEL test: Another good one ( I forgot to turn the PoScope monitor off before disconnecting the cables)
CBAIII test 1: 0.960Ah; good curve. (That's one of the inconsistent ones!)
CBAIII test 2: 4.064Ah, good curve.
AMPEASEL test: Another good one:
CBAIII test 1: 1.214Ah, good curve.
CBAIII test 2: 4.088Ah, good curve.
AMPEASEL test: I stuffed up! Instead of turning to 30A at 1min, I turned it off! But a good stick, nevertheless.
CBAIII test 1: 1.021Ah, good curve.
CBAIII test 2: 4.084Ah, good curve.
AMPEASEL test: Another good one.
CBAIII test 1: 1.194Ah, good curve. (One of the inconsistent ones)
CBAIII test 2: 0.105Ah, early drop, bad cell? Stopped manually.
AMPEASEL test: A very very marginal stick! Note the steep drop towards the end of the 1min @ 100A phase. It recovers briefly, but the weak cell in the pack empties after a brief time at 30A. Because I terminated the discharge very soon after the obvious end of the fall in voltage at 1min:40sec (= a single cell has finished falling to zero V), there was a smooth immediate rebound in the overall stick voltage. The cell which dropped to zero volt bounced back up to around 1.1V immediately.
CBAIII test 1: 1.104Ah, good curve. (inconsistent with the two others)
CBAIII test 2: 0.02Ah, very early drop, terminated manually. Bad cell!
AMPEASEL test: Similar to S06: It just manages to hang on for 1min @ 100A, with a steep drop at the end. Then, early in the 30A phase, a single cell in the stick drops to 0V. But this time, I let this continue for about 45sec. The result of this 45sec reverse charging event (is it that, strictly speaking?) is the kink in the recovery curve after the end of the discharge, at about 2min:25sec. The sudden rise by about 1V is caused by the recovery of the weak cell from around 0V to around 1V. The longer it was reverse charged, the longer it will take to bounce back up. If it was for too long, it would never bounce back!
CBAIII test 1: 1.805Ah, good curve.
CBAIII test 2: 0.072Ah, good curve.
AMPEASEL test: I stuffed up the recording...forgot to save it! Cell reversal during 100A. Did not recover when switched to 30A at about 40sec; delayed voltage recovery of single cell after turning off (like with stick 07); Switched off early due to cell reversal.
CBAIII test 1: 1.588Ah, good curve.
CBAIII test 2: 2.183Ah, good curve.
AMPEASEL test: A good stick, but clearly less capacity than the best ones.
CBAIII test 1: 1.782Ah, good curve.
CBAIII test 2: 1.195Ah, good curve.
AMPEASEL test: A marginal stick. Copes OK with the 100A phase, but the 30A phase is only abot 2minutes long. After the discharge, it recovers to over 7.7V! This is due to the majority of cell in the stick still not being anywhere near empty. Just one cell hit empty (t 3min:20sec), and once it bounces back up to 1V, the remaining charge in the other 5 cells brings the resting voltage up higher than it would be for a good stick which has been able to discharge most of it's energy.
That will have to do for this post, the forum software will not allow more than 10 pictures per post!
There is always a way if there is no other way!
The writer of this post accepts no responsibility or liability resulting from attempts to repeat or perform the procedures described in this post. This information may be used at your own risk.