Firefly Electric Conversion

[jakobnev]

I just remembered Daox's DIY PIP and I think the same thing happened to him:

[Stubby79]

Originally Posted by jakobnev

I just remembered Daox's DIY PIP and I think the same thing happened to him:

That bolt looks pretty loose (thought I read his post, and he didn't believe it was)...the lock washer isn't anywhere near being compressed flat.

Good to know what can happen if left alone, though!

[WyrTwister]

Is that repairable ?

Does not look good . :-(

God bless
Wyr

[me and my metro]

It looks stainless, probably seized. I hate stainless bolts.

[Daox]

Originally Posted by Stubby79

That bolt looks pretty loose (thought I read his post, and he didn't believe it was)...the lock washer isn't anywhere near being compressed flat.

Good to know what can happen if left alone, though!

Yeah, either I missed it (most likely) or it came loose (much less likely). I don't think it was binding on anything. Definitely teaches you to double and even triple check!

[Stubby79]

The LED headlight bulbs I ordered off Ebay back in October arrived yesterday.

This kind:


Tested them out this morning. Quite pleasantly surprised with how bright the first one was at the bench test. Also please to see that the circuitry on them doesn't require specific polarity...they work any which way you put power to them. Great.

Remembered at the last moment to see how much power they draw. First one was 1.0A on high, 0.5A on low. Decently low, considering how bright it was. The second, though, was 0.5/0.4. Thats when I clued in that it wasn't as bright as the other, either.

I'm assuming the "great deal" I got was one of a bunch of cast-offs that didn't pass quality inspection or something. Maybe they both failed, though I could see one of them being bad and the pair of them being cast off together because of it. This isn't the first time I've picked the cheapest seller, usually in China, only to end up with a B-grade product. Well, you get what you pay for.

Of course, I usually complain and get my money back. Which I had already done with these, since they "never" showed up. Maybe I should have been more forgiving? I mean they were only 3 months overdue. The shipping label says they sent them on time. Oh well, I would have had to have *****ed about one of the lights being faulty anyway.

I stuffed them in my EV anyway. They're still better than the several generations past LED bulbs I had in there. The good one throws out what seems similar to a normal bulb's light. Not bad for something running on 12 watts, instead of 55. I might almost recommend a set, if you have good reason to want to cut down power consumption. Won't swear that they will light up the highway for ya, though. If you need that, you should probably shell out the dough for a decent set.

I keep trying new types of LED bulbs whenever I get a new-to-me vehicle, so I've got a pretty good idea of what works already, but I keep trying to see if the newer ones are better.

I wasn't happy with the amber 194's I had in the side markers (5050 chips), so I tried these:


Which I am much happier with. Brighter, and they glow evenly and throw the light all around, so you don't have the bright spots that give away that they're LEDs. I recommend them. (Note that these are longer than regular 194s) I would feel safe ordering more with that same kind of "filament" in the middle.

I have also bought these "COB"(chip-on-board) for my turn signals:


Which are nice and bright...though they don't get a whole heck of a lot brighter on "hi" as they do on "low", so they might not be the best choice for the 1157 bulbs...brake bulbs in particular. For that, I recommend this type:


Which are usually sold with the tags of "7.5 watt" and "Cree". They're relatively pricey, but they're the only ones that I've found that do a decent job of mimicking a normal 2-filiment bulb. Meaning they give out modest light on "low" and a heck of a lot of light on "high". All the others seem to lack on a noticeable difference. I don't care to screw around when it comes to my brake bulbs.

So, yes, you can do decent off of ebay bulbs. I would just recommend going with popular sellers, to avoid getting the B-grade crap. And, I don't know about the rest of the world, but when I order from Hong-Kong sellers, I usually get my stuff within ~2 weeks. When I order from mainland China, it takes a month or more...and about a third of the time, I never receive it, and, since the only reason I ordered from mainland china was to save a buck, these tend to be the sellers who send me B-grade crap.

I can make further recommendations if anyone is trying to figure out what works and what doesn't.

(maybe one of these days i will have some actual progress to report!)

[Stubby79]

Wow, a month gone by without any real progress. I blame the cold weather. Which has finally passed. I hope.

But, I've just run out of excuses. The final pieces to my puzzle arrived yesterday. Not what I was originally planning, but I had kept my fingers crossed and searched daily for a deal on these, and said diligence and patience paid off. No need to continue my home-made version.

Viola! :


A matching pair of 72 volt chargers. Fairly light weight, very efficient, intelligent, run on anything from 100v to 240v AC and are good for 1kw each. For less than I could buy cheap 10a chinese chargers off ebay for, of unknown quality or efficiency. Hooray!

Just tested them out on my LiFePO4 pack. They started charging it up no problem, without being programmed specifically for it. And my BMS will cut off the charge once the battery is full. Once said BMS is finished being installed, I'll find out what voltage the chargers cut off at on their own. There are already a few different charge profiles in them if I need to raise or lower the final charge. I'd like to have the chargers turn off a few volts before the battery is 100% charged (87v) just in case my BMS's ever fail to interrupt it, so as to lessen the likelihood of any individual cell getting over-charged. The chargers appeared to be cutting back current starting at about 82 volts, which is just about right. At a guess, they're set to maintain the battery at a steady 82.8v float charge, which, were these 12-volt lead-acid batteries, would be 13.8v -- exactly what you want for a float voltage for your typical lead-acid battery. And works out to 3.45v per cell for my LiFePO4s, which is almost perfect, IMHO, since that's ~99% charged and falls 0.2v short of the 3.65 max voltage. We'll find out for sure once that BMS is installed.

It looks like my plan to use 72-volt "architecture" in twin to keep costs down is going to work. That's about the maximum you can get small BMS/PCBs, which are a tenth the cost of a professional one good for a 144v system. Same goes for chargers. I could have easily spent $2500 for a BMS and a charger, whereas I've now about $350. Which is about what I was aiming for. Mind you, it's not every day you can find a matching pair of high-quality chargers cheap.

I had also ordered this a couple of weeks ago:



It's a hall-effect transducer, with specifications to match the one that Mechman was using with the mini-motor controller he was using to control the field on the sepex motor he had, both of which are now in my possession. Rather than buy a serial adapter from Kelly to allow me to reprogram the controller, I went looking for a transducer with the same properties as the one he had. It only cost about $5 more to have one that matched rather than a generic one, which is cheaper than having to buy the serial adapter as well. Field control solved.

The weather has warmed up. I now have all the parts I need to finish this conversion properly. My kid is going to Gramma's house for a week...yeah, I'm totally out of excuses not to get on with this. Wish me luck!

(Woot-woot! I have 2kw worth of chargers!)

[MetroMPG]

Good luck!

Nice summary of your LED bulb experience too.

[Stubby79]

Break time! 4 straight hours of staring and soldering tiny wires. It's both peaceful and monotonous all at once.

My back is telling me that it's glad I built my work bench to the right height for me to stand at for hours on end.

Originally Posted by MetroMPG

Good luck!

Nice summary of your LED bulb experience too.

Thanks!

[Stubby79]

I haven't made much progress since last time.

I was gung-ho and working on all sorts of things a couple of weeks back. Right through the weekend before last. By Tuesday, just before starting back in on this, I became sick as a dog. Could have been nipped in the bud, were there walk-in clinics open really late or really early. Instead, I ended up going to the hospital at some weird hour in the morning.

A week later, I finally decide it's time to get back to it...and some junkie breaks in to my work shop 2 hours before work is over, and I have to come home early to deal with the cops and repair a broken door/deadbolt.

Sigh. I seem fated not to be able to make any progress.

At least I made decent progress before. I mentioned lots of wires, right?



Wires, wires, everywhere!

Note the cheap little cell monitors? They're doing double duty...well, their connectors are, as I soldered the BMS/PCB connectors to the solder joints on them, so I wouldn't have to splice in to any of the wiring I had on the battery already.
Note the little black boxes on the right hand side? They're mini relays. They turn off the ground wires going to each of the cell monitors, so they're not sucking the battery dry (however slowly) while the system is turned off. It also means I don't have to unplug them to get them to shut up if/when the low-voltage alarms (the whole point of the things) goes off. Said relays do no interfere with the BMS's wiring, as that would annoy or defeat it.
The rainbow spaghetti is the wiring going to the BMS.

That's this little guy:


Note the two blue LEDs turned on? I was impressed when I discovered it had this. It tells me when each cell is fully charged, so it's easy to tell which, if any, cell(s) are imbalanced by which are or aren't lit up.
As you can see, my mucking around with sucking power out of random cells threw it out of balance, so only 2 cells hit full voltage before the voltage limit protection kicked in and disabled charging any further. Exactly what this little guy is there to do. That and to slowly bleed off power from those cells that are higher voltage than the others, until they're all closely balanced.
The LEDs make this particular great compared to other cheap ones that don't. Like the other one I have for the other half of the pack. Maybe I'll splurge and drop another $50 or so on a second one of these.
$50 x 2 units is a heck of a lot cheaper than full blown BMS's that start around $1300...

I didn't wait for the mili-amps to bleed off the battery. I started charging individual cells while (Safely) circumventing the BMS. The second time I put it on charge I got more lights:


After some more topping up...


After which, they were so darned close to all being full that I let it rest and let it bleed down the voltage, so on the 4th charge, they all lit up before the voltage limit protection kicked in.

As you can see here...


I also wired in a 50-amp Anderson plug to the BMS for charging. And wired in a matching plug to each of my chargers. I chose white 10-gauge wire for the BMS charge leads, so it would blend in with the white of the pack. And I clamped on my (sub $50 ebay) clamp meter to verify the current output of the chargers.

All in all, you're looking at probably under $100 worth of BMS, wires, cell monitors, relays, etc per 72-volt/24-cell pack. (Higher voltage/more cell BMS's and chargers aren't readily/cheaply available, unfortunately.)

Of course, that's a hell of a lot of wiring to have to put on. But you'd have to make almost as many connections with a fancier BMS.

I followed it up with putting a little black box on my accessory battery. By that point I had gotten in a rhythm with all the soldering and heat shrinking and everything else, so doing one more was just a matter of giving myself the time to do it.


So now I'll know if any cell voltage gets too low there, too.

That's how far I got by my previous post 2 weeks ago. I still need to seal up and mount the BMS, otherwise this half of the battery is done.

Now I have to do it all over again with the 2nd pack.

Which I was test-fitting:


One half just behind the lower rad support, the other half on top of it:


Which will require doing some surgery, followed by welding in some racks for them. Assuming I don't change my mind again in the meantime about where I'll place them...