With less than a week until I install Ron's newly developed prototype pack, I'm trying to gather as much information about the stock pack as I can. With the help of Peter's BCM Gauge, I have been logging the performance of my pack during a specific test run.
The run is a 4,000' climb over about 15 miles. I try not to use regen while going up, and assist while coming down so as not to complicate the numbers. Using MIMA, this is pretty easy.
What I'm finding is very interesting, and I wish I knew if it was normal or not. We really need more people logging data like this. My pack is about 1.5 years old, replaced under warranty. It has never been grid charged.
During this first run, I experienced a recal for the first time. I was quite surprised. The recal happened at about 1/3rd left on the SoC meter. I was using PIMA, and was very aggressive with assist overall.
As you can see, I inputted about 3.18Ah back into the pack.
Test #2:
This trip I was much more gentle with assist. The SoC gauge behaved normally with no recals. It dropped steadily down to 3 bars, hung there for a bit, then dropped off to one bar before limiting MIMA - just like normal. The graphs look very similar, however the gauge behaved how I have come to expect it to behave. The SoC drop off is when the 3 bars finally went to two.
Despite "feeling" like I got much more out of the pack, and the SoC gauge behaving normally, I was surprised to see that once again I only got ~2.6Ah out of my pack.
Once again, just over 3Ah inputted. I'm beginning to notice a trend. But this can't be normal.. can it? Is my pack already that deteriorated after only 1.5 years? I haven't noticed any anomalous behavior with it in the year and a half since I got it. Very strange. So.. is this normal?
I'll continue to update this thread with data that I get. I would like to do a grid charge and BCM Reset on my pack to see what that does to these numbers.
If anyone wants to look at the raw data and my calculations etc, feel free:
Once you have done a grid charge on this old pack it will be interesting to see the difference.
Once the new pack arrives don't change anything with the gauge so we get consistent data into the spreadsheet. I suggest you grid charge the new pack overnight with the fan running when it is first installed to make sure it is balanced before you start.
With your data logging speadsheet just a though about how it works.
Lets assume you get 10,000 samples on a trip. If you total up the samples where the current is positive and divide by the total number of samples you will get the average Positive current (regen) for the trip. Ditto with the negative.
From the time stamp you can work out the elapsed seconds then as you say do some maths. I'm just trying to make sure we get the right result for AH.
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IMAC&C HCH1 $50 inc software and pcb.
Yeah, me too. Like I said I'm not good at math at all, and usually rely on cross-checking to determine whether my answers are correct. They seem to be though. Go ahead and check out the spreadsheets, I added them to the post.
Basically I broke each sample up into even slices of time. Example: If the data set is 30 minutes and encompasses 10,000 samples, each sample is
30 minutes * 60 = 1800 seconds / 10,000 = 0.18 seconds/sample. You can see that this matches up well with the actual timestamps.
Once you have time, you can calculate Amp hours.
I wonder how much the missing tenth is skewing results though? Probably not more than a few hundred mAh overall?
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Bumblebee Batteries, LLC - Helping your hybrid get from point A to point Bee!
OK Try this vesrion 3.20 specially for the logging. The amps column is now the full resolution from the sensor to two decimal places. You need to divide the value by 100 to get the amps before the decimal point.
The no data message has been removed to fit it into code space.
Edit
I received my pair of transceivers today
__________________
OBDIIC&C $50 inc software, pcb, switch and obdii plug.
IMAC&C HCH1 $50 inc software and pcb.
Last edited by retepsnikrep; 06-01-2011 at 06:32 AM.
I think 2.46 AH from a pack which has never had a gridcharger may be reasonable and representative, 2.46 AH probably represents the weakest stick in the series of 20.
April 2009 I removed my pack to benchcycle the sticks, for first discharge at 10 Amps, the best stick yielded about 2.5 to 3Ah, the worst, only 400mAh !!!!.
They all recovered, even the 400mAh duffer, though it took extra cycles to bring it into capacity line. Two years later, thanks to grid charging, my pack still performs like new.
It is staggering to see the variation in capacity and therefore balance of the pack prior to the bench cycle, I will have to dig out the spreadsheet and post on IC.
From my exercise I noted that for 10 amp charge and discharge between limits of 5.4V to full volts, for discharge / charge ratio the figures came out as 89%,
I suppose, it's just a little surprising. I consider my pack to be healthy, other than the anomalous recal on the first data logging run - so I was expecting to see something around 4Ah, which seems to be the number thrown around as conventional wisdom.
Ron's new pack is arriving today, and I need to put together my grid charger.
I've also not played around with flashing the BCM Gauge PIC to different code. I'm very interested in having higher resolution on the amp data, so I will try this ASAP.
All this along with trying to coordinate the payment and transport of Insight #3...Too much on my plate, I need another 4 day weekend..
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Bumblebee Batteries, LLC - Helping your hybrid get from point A to point Bee!
With less than a week until I install Ron's newly developed prototype pack, I'm trying to gather as much information about the stock pack as I can. With the help of Peter's BCM Gauge, I have been logging the performance of my pack during a specific test run.
Eli, can you identify whether the battery fan is on or not and its' speed? It would be important to compare how much forced ventilation is needed.
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2000 MT #4227 175K miles - Citrus Yellow, BetterBattery
I could, yes. The data won't be incorporated into the spreadsheet automatically unfortunately, so I'm not sure how much it will be worth.
You can see the fan cycling on and off during the Mountain Run 2 Down graph, if you look at the temp.
Hmmm. I could use a watt-hour meter to record the total amount of energy consumed by the fan. That won't give high/low fan speed, but it would give an overall measure of how much the fan was running during the data logging session? Might be more useful than anecdotal notes on the fan's behavior at least.
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Bumblebee Batteries, LLC - Helping your hybrid get from point A to point Bee!
Hmmm. I could use a watt-hour meter to record the total amount of energy consumed by the fan. That won't give high/low fan speed, but it would give an overall measure of how much the fan was running during the data logging session? Might be more useful than anecdotal notes on the fan's behavior at least.
It would be better than nothing. It would give us an indication of the temperature performance under load.
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2000 MT #4227 175K miles - Citrus Yellow, BetterBattery
1) 3rd data logging run up the mountain tonight
2) Grid charge overnight tonight, reset BCM
3) Install Peter's latest BCM Gauge software with higher resolution ampere logging
4) 4th, 5th, 6th data logging runs on OEM pack
5) Install Ron's new prototype beta pack
6) Begin logging data on new pack
We'll see if I can complete this by the end of the weekend.
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Bumblebee Batteries, LLC - Helping your hybrid get from point A to point Bee!
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Data Logging With the OEM Pack
