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[guity]

Richard, at this point in time I would tend to agree with you in that most of my concerns about my batteries might be written off to the normal loss of performance that comes with lower temperatures.  The bike seems to keep chugging along, however, despite how much I have beaten and battered it.  At any rate, I am hoping this logger will provide further clues as far as whether there might still be a runt battery or two hiding amongst the pack...

[picasso]

Is a few diagrams on endless forums about how to tie in 3+ 8cell loggers into a nice little system to watch them all. But what you have now looks much better then probing away one by one.

[guity]

Yeah mine is definitely not as cool, but I already had to buy 2 of those things because one broke so Im not excited about buying another 2 of them.  I kind of hope to just bring it out every once in a while to get an idea of how badly balanced they are or if I suspect a runt.

[guity]

Before I forget for the 5 millionth time, here is the latest cycle analyst stats spreadsheet...

[guity]

OK this will require 4 posts, in each post an attachment of a Word document with 2 graphs in the document showing the same 52-minute span of logging that includes driving back up my hill at the end of a trip to work and back.  These graphs tell a fascinating tale as far as I am able to tell...

[guity]

OK second pair of batteries...22 and 21 (according to my backward numbering system -- to the cell logger they are 3 and 4)

[guity]

OK third pair of batteries, guity's 20 and 19, cell loggers 5 and 6...

[guity]

And finally guity's batteries 18 and 17, cell loggers 7 and 8...

[guity]

If you take a look at the graphs, you can see that battery 20 (guity number) or 5 (cell logger number) takes a dive at every opportunity, much lower than every battery.  The biggest dive came while coming back up the hill today, but you can see there were other dives probably corresopnding with every time I accelerated hard from a stop.  You can also see that battery 24 (cell logger's 1) and 18 (cell logger's 7) sucked as well, though not as bad.  I guess it is a bit too early to jump to conclusions until I have logged the other 16 batteries as well...

But interestingly enough, you can also see that all the bad batteries, even the worst, comes back up even with the others when there isn't a heavy load.  Hence, by the time I got the bike stopped and checked the voltages, none of the batteries looked all that bad...

[guity]

OK, today was a shorter ride of around 12 miles, but the graphs still show the hill taking its toll on batteries 4 (= guity's 13) and 7 (guity's 10) with 4/13 being the really horrible one.

[guity]

The worst battery is in this pair:

[guity]

A couple of reasonable batteries here:

[guity]

Batteries 7 (cell  logger)/ 10 (guity and 8 (cell logger)/9 (guity):

[Richard230]

Hi Guilty. Thanks for going to all of the trouble to keep track of your battery performance. I continue to find it interesting how your bike's performance differs from mine. It would appear that my GPR-S is more efficient than yours, or perhaps it is just more constrained by my controller or my batteries. My watts per mile typically averages around 80 per mile on my way back and forth to work.  Riding 10 miles up and down three hills at full throttle uses around 13 or 14 Ah. Top speed reached according to the CA is usually about 66 mph (60 on the bike's speedometer). As I have said before, my entire 24-cell battery pack usually runs around 51 volts and draws around 160 amps while under a load at around 30-40 mph, but that improves to around 60 volts once the speed rises to over 50 mph and the power draw drops below 100 amps - at full throttle. The faster the motor spins, the less power it draws, but it never cuts off the way my Etek-RT did when it reached 62 mph. I continue to be impressed with your battery performance. Even your worst battery is better than the average of my battery pack, both under a load and at rest. I think my Hi Power batteries are not all that high power.

I just turned over 1000 miles and one of these days I need to summarize my experience with my sepex GPR-S now that it is most likely fully "broken-in".

[guity]

Hmmm, I guess I either have to give you my batteries or you have to give me your motor!