Assembled Hi-Power LiPo battery packs - any interest?

[deVries]

Just finished two of Rodney64's 6 packs.

Isn't this the most compact 15 Ah, 22 volt pack you've ever seen?



I still need to solder the balance leads in, as well as the 90 degree bolted terminations. But I was surprised at how quickly they come together. With a bit of practice I should be able to belt out a 24s3p pack in a day.

I have also taken about 3 gig worth of instructional footage, and while I could stitch it all together and upload it to youtube I might just wait for DeVries to chip in.

You know I'm ready!

Do you have a high-speed internet connection? Send me a PM, so we can get this transferred to me.

Thanks.

[Olly3012]

Hi jonescg hope you can help me out ay im stuck on battery choice and you look like the man, I have just purchased a CroMotor and 24 FET 4115 MOSFET 84-132V Freeway Speed Controller (max battery voltage 150V) i was thinking 6X 6S5P packs and under charge them may be built into 3 even sized packs (6S5P side by side) any ideas im in Tas a rough cost inc post cheers.

[jonescg]

Hi Olly,

So 36s all up? 133 V nominal charge at 150 volts? Can be done Depending on how you want the final size and shape I can make them in any arrangement you want. Three blocks of 275 mm x 100 mm x 150 mm? (LxWxH) would work easily, but would still require come cables joining the series connections.

These packs are awesome for their compact size and power. Energy density as better than A123s, about the only drawback is the cost and the fact that LiPo isn't exactly set and forget. Cost to you is about $1.10 per Wh, so at 36 x 3.7 x 25 Ah = 3330 Wh, or about $3600. The high cost is the fact that the cells need to come from HobbyKing in bulk orders (easiest way to get a lot of cells all at once). After customs, GST and shipping they work out to be 32% higher than the storefront price.

It still blows me away that the individual cells require less handling and labour than 4s hardpacks, yet cost more

Anyway, happy to help

[jonescg]

Rodney's pack is almost ready. Because of the dimensions of the Phasor bike, we couldn't just do one long block up and back (that would have been considerably easier) so we had to split the pack up into 4 x 6s,3p blocks. We can't load the whole lot in one go, so the sub-packs are loaded individually and bolted together using 90 degree terminations.



The pack measures 400 mm long, 150 mm high and 81 mm wide.



I just have to finish the last two 90 degree terminations and solder the balance leads on. And we're more or less done!

[Ricky_nz]

Nice!
How hot did the cells get when soldering the copper bars on?
Are you planning to cover the copper bars with some form of insulation, maybe kapton tape or similar?

[jonescg]

I have the irons on for about 10-12 seconds, and most of the heat stays in the copper block while the solder melts. The cells will only really get the last bit of heat as the solder on the tabs gets molten, and this is only quite brief. As the whole lot sinks down I take the irons off and dab it with a sponge and cold water. I always feel the cells afterwards to see if the got hot, but nothing does. The tops of the cells get a bit warm, but within about 30 seconds they are cold again.

And yes, for the mercy of Dog I will be insulating the terminations! I don't know what would be ideal, maybe Kapton tape or just a few rounds of PVC tape? I want the balance leads to stay out of the way as best I can manage.

[Ricky_nz]

I have the irons on for about 10-12 seconds, and most of the heat stays in the copper block while the solder melts. The cells will only really get the last bit of heat as the solder on the tabs gets molten, and this is only quite brief. As the whole lot sinks down I take the irons off and dab it with a sponge and cold water. I always feel the cells afterwards to see if the got hot, but nothing does. The tops of the cells get a bit warm, but within about 30 seconds they are cold again.

Sounds good

And yes, for the mercy of Dog I will be insulating the terminations! I don't know what would be ideal, maybe Kapton tape or just a few rounds of PVC tape? I want the balance leads to stay out of the way as best I can manage.

I would stay away from PVC electrical tape because it leaves leaves a horrible mess. Kapton tape might be better or even sheets of thin polycarb / lexan glued over the bars on each brick or group of bricks and then you could wrap the bolted connections in self amalgamating tape.

Edit: If you use clear lexan then you can show off your work! It would also give better protection to intruding objects than just tape.

[Rodney64]

Looking good Chris but I would be feeling better if I had a frame to put it in. How did the shed handle to storm. 150 high is that to the top of the terminations.

[ohzee]

hah yea Rodney I am jealous you sure are getting ready for the new bike.

Battery looks very nice. Makes me want one.

[jonescg]

Looking good Chris but I would be feeling better if I had a frame to put it in. How did the shed handle to storm. 150 high is that to the top of the terminations.

I had to leave and shut the door when the wind got too strong. I could see the roof lifting!

The majority of copper terminations are at ~143 mm high, so I figured 150 would account for the balance leads and Method's boards. The top of the bolted termination would be closer to 160 mm, but fortunately there are only 3 of them, and these are in the middle where clearance is greatest.

[Rodney64]

That's good as you say plenty of room.

All of my components from CRC have arrived.

Looking at buying a dual suspension frame for my son made a couple of offers and one with a counter offer. At the moment we can keep up as our bikes are similar. But when I get the phasor with the H3580 things will be different.

He's grown out of his current frame in 18 months.

This battery box I am planning on building if I make it 180/170/105 then this should be ok for a 14s pack.

[sn0wchyld]

I have the irons on for about 10-12 seconds, and most of the heat stays in the copper block while the solder melts. The cells will only really get the last bit of heat as the solder on the tabs gets molten, and this is only quite brief. As the whole lot sinks down I take the irons off and dab it with a sponge and cold water. I always feel the cells afterwards to see if the got hot, but nothing does. The tops of the cells get a bit warm, but within about 30 seconds they are cold again.

And yes, for the mercy of Dog I will be insulating the terminations! I don't know what would be ideal, maybe Kapton tape or just a few rounds of PVC tape? I want the balance leads to stay out of the way as best I can manage.

just an idea, you can get spray on rubber, it has great insulation properties/wear protection and peels off if you need to access the parts again at some stage.
http://www.ebay.com.au/itm/280822637693?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
pretty expensive stuff (I wish i lived in usa right now, where this stuff is about $7 a can) but might be a good option over tapes, given the uneven surface.

Great work by the way. I'm saving this thread for later, once I've built a bike to accept a single large battery.

how hard would it be to make up a 8-16s 10ah square pack (or close to square)? I'm thinking these could work great for a modular pack.

[jonescg]

I might look into that stuff, or something like it. It might just end up being insulation tape for now.

I have boards to make 3p (or 15 Ah) packs. Most folks are after something in the 40-100+ volts region, indicating faster than 40 km/h will be the norm. I think at these speeds, you really want a bit more capacity up your sleeves, so I'd recommend 15 Ah for such a pack.

If you want it to be square, or close to it, the number of cells in series down one side still must be an odd number. See MS Paint image for demonstration.

Odd numbers means the first column will line up correctly for the second.

A 15s3p packs would measure 135 mm long, 150 mm wide and 150 mm tall. It would have a nominal voltage of 55.5 V and pack about 832 Wh. Weight - 5.9 kg.

[jonescg]

Well except for insulating the tops of these packs, Rodney's pack is built! 24s3p, 88 V nominal, 100 V hot off the charger and 84 V when it's spent.



The balance taps can be tapped into just like any 6S pack would, or you can plug them into Method's HVC/LVC boards.



400 mm long, 81 mm wide and 160 mm tall. I would recommend bolting these sub-packs together with short stainless steel set-bolts (threaded all the way to the head) and washers, just to avoid any corrosion issues.



I'm going to look into something like silicone rubber for sealing the tops of these. If you have the room, two rows of 12s would be stronger, but this is a practical way to do it.

Next step, balance charge and a few cycles to see how they go. Each sub-pack is exactly 23.20 V

[Rodney64]

My elcom bulk charger should be here shortly. After its balanced it would be nice to run a couple of cycles with my bulk charger. It's been set up for 100.8v max.

[jonescg]

I'm inclined to go for a layer of silicone rubber for these packs, but for the race bike I might look into laying a thin sheet of stiff plastic down with double-sided tape or maybe even just tape it down with cellotape or the like. I just want to make sure the balance wires don't rub on the copper blocks, causing a short.

If anyone is keen on a pack, let me know as I will be making another cell order soon (in the next 4 weeks anyway).

Cheers

Chris

PS Rodney -how's the Phasor frame coming along? Any progress photos?

[Rodney64]

When I last talked to phasor they were finishing frame 2. I'm frame 6, No photos but picked my colour, candy blue.

http://www.primo-powder.com/color-charts.php

[Rodney64]

Purchased some aluminium trays from work to sit my chargers on.

[jonescg]

Just a quick update - I'm going to be ordering some more 40C cells through the retail arm of HobbyKing at the end of the month, since I don't need to buy $2000 worth of stuff. However, if anyone in Australia really needs a grand worth of stuff from HK let me know and I'll put a big order in. Amazingly, the cost of both systems is identical, the only difference is how soon the cells arrive and how much stuff you can get shipped in one order.

I reckon I might be in line for a good tax return this year Who knows, might be a deposit on an inverter, custom frame, battery pack...

[AussieJester]

CHRiS, I can transfer some money for my pack Thursday week (pay day) if you like?

If any other locals are looking to get into a lithium polymer pack for their e-bike, I highly recommend getting a pack from CHRiS, I checked out a sample late last week and was hugely impressed by the Pack construction...

Chat with you soon either way CHRiS

KiM

[Rodney64]

Balance charger set up and waiting for my phasor frame.

[jonescg]

Nice! Those HP power supplies sound like turbines eh?

I will cut the termination bolts back to about 15 mm to save you from having to fiddle with a pair of ring spanners in a confined space for too long.

[voicecoils]

Nice! Those HP power supplies sound like turbines eh?...

They sure do make a bit of noise!

When I've got 6 of my HP supplies fired up it's going to sound like a swarm of angry bees.

Nice looking charging corner!

[Hyena]

Looking good Chris. Any plans to heatshrink them or add some other form of external protection ? Or are you leaving that up to the end user ?
I've been looking around for some fairly sizable headshink (HK only sell up to 100mm) but haven't had much luck.

You guys do know about shorting the pins (or putting a resistor in there) to drop the fan speed on those server PSUs right ? If you're running 2 in series on the icharger I doubt you're taxing them so there's minimal chance of them overheating.

[Gregory]

Theres thin blue stuff on ebay. similar to the turnigy lipo covering. 300mm when flat.
http://item.mobileweb.ebay.com.au/viewi ... 2696421066

Not sure if that will work from my phone but you'll figure it out.

Also grin cycles used to sell a thicker type of heat shrink in large diameter.