ianmcnally donated a spare NiMH pack to the project; 36V f-cell, so 13Ah in theory. It arrived just as I was leaving for work today. Got home and checked, it wasn't quite fully charged. First thing I did was just pull the shells off the little powerpoles so I could insert them under the tips of the much larger multiple contacts on my charger, then I stripped the insulation off the thermistor wire (it didn't have a connector on it) and stuck that bare wire end into the thermistor powerpole on the charger.
Started charging just like it should, at 4A. Gets warm a LOT quicker than my other pack (9Ah D-cell) does, though. Not sure if that is because of the cell resistance (higher?) or if it just conducts the heat out of the cell better.
Last working picture of the Turnigy Watt Meter:
before the unfortunate event later in this post.
Once charged, which verified operation of the pack, I took the wrappings off to verify it's structure/integrity, and found it's actually a 24V pack with half of another identical 24V pack, in series:
First I carefully wiggled the powerpole contacts until the wires pulled out of the crimps (which was a shame to do because they looked PERFECT, but i saved them for later use on whatever I next need them for), then I crimped on and soldered some ring lugs to bolt to my anderson multipole cables (which all have ring lugs on them from their original sources).
Since I will need 36V for the Fusin headlight (and it's power meter), I decided that since this pack is 13Ah and my other is 9Ah, nominally, I could just run it off of this larger pack, even if I wire the packs in series as I intend to do at least for testing. So I bolted two multpoles with the low-voltage keying on the ring lugs just added above. One is for the light, and the other is for the series harness. Added a single powerpole connector for the thermistor to match what I used on the other pack, for charging.
Then I proceeded to bundle it up tightly, by white-gluing the cardboard rings around the sets of cells to each other, then strapping down with packing tape, and a little duct tape when I ran out of packing tape (which doesn't stretch as much as duct tape, so I'd rather use the PT). I also used some old nylon "clipstrips", which we regularly toss out at work--lots of products come prepackaged on these, ready for hanging up on store aisles for easy display--just add pricetag. Often we need them on the shelf peghook instead, so we end up tossing the strips. Sometimes I save a few, and have a fair collection of various thicknesses and types of plastic.
I used nylon ones here, snapped at their scoring lines (so you can break off the empty sections as product is purchased). I only need them to cover the ends of the cells, so that I can be sure they will be spaced away from anything that could short them even if the tape comes off in the heat, since my cargo pod is metal. Also to help absorb a little vibration.
Then taping down and adding a second, wider strip, of clear plastic clipstrip just a hair wider than the pack, wrapped from the bottom up both sides and just about an inch over each end at the top.
I dozed off in the chair with the pack in my lap somewhere around then, can't remember exactly. Woke up probably a few minutes later and finished up the taping/etc.
Then I started working on the wiring harness. You might have noticed the red, black, and gray multipole shells. Black and gray will fit each other, but none of the other colors will. THe blue on on my charger shouldn't, but I dremeled and filed it's key off so that it fits black/gray too, as at the time I didnt' have any more of the others not in use. The red ones will be used to prevent plugging the 72V pack output into the 36V charger, or the 36V light, and blowing stuff up.
Red on controller, red on series harness output. Black for one pack and gray for the other, just so I can always match them up and remember which one is plugged in, if I use only one. To use one, I made a "jumper" multipole, which just has a wire from + to - on it, which shorts the empty battery pack connector, to allow me to use just 36V. It's original intent was so that if the 9Ah pack ran out but the 13Ah pack still had lots of power (should), then I could disconnect the 9Ah pack so I don't overdischarge it, and still have assist.
The new pack now goes up front, scooting the other pack back a little. Tehy're snug in there now. Controller will bolt to right side of pod, just inside and forward of the lock that's on the lid.
Then I decided to start testing it. First I figured I'd see what the voltage was, and as I already had the Turnigy Watt Meter out, I temporarily swapped it's blue housing for a red one, plugged it in, and got zilch.
At first I thought I wired the pack series jumper cable wrong, but a meter showed correct voltage and polarity out of it. Then I realized I'd just put 86V on a 60V device, and I got really sad for a minute, until I remembered Doc Bass's thread about fixing that, which I am now going to need.
For some reason I'd gotten confused and thought it was 150V not 150A, then hooked it up before my brain could realize the mistake and stop myself.
Then I also decided before I hooked it up I'd better recheck the Lyen controller thread, to make sure they were already setup for "72V" packs (FETs and phase caps are 100V, but coudln't remember the rest), and found I'd need to mod it for above 60V for the LM317 input divider. That'll have to wait for a bit, so I guess no 72V tests yet.
But at least I didn't blow it up first and THEN check.
Guess the Turnigy's death was more useful than I thought, or I would've blown up the controller instead!
Since I am way too tired to be modding electronics right now, and I have a Freecycle trip tomorrow afternoon to pickup a couple kids' bikes, I left well enough alone and will just use the system as 36V, swapping batteries when I need more power on the way back home (since either one of the packs will probably run dry before I can get all the way back, as I won't be going as slow as I was on the Hachi/park trip, or pedalling very much, as it will be really really really hot outside).
And now it is sleepy time.