Assembled Hi-Power LiPo battery packs - any interest?

[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.

[jonescg]

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.

Thanks Jay!

I was thinking about heat shrinking the lot as the cellotape looks a bit ghetto, but it works at least. I think we'll put a layer of silicone goo down on top of Rodney's packs because of the way the balance leads are arranged (like tree roots) so the silicone should make sure no wires are able to rub on a block of copper it shouldn't. For packs made from one single stack of cells, I'd say a layer of thick plastic film (like 0.5 mm to 0.7 mm thick) with notches cut out for the balance wires would achieve this, followed by shrinkwrapping. or 100 m of cellotape

[Hyena]

Cellotape ? C'mon man, atleast use duct tape
That flexible sellys gap sealer type stuff is probably cheaper again than silicon at around $3 a tube for covering a large area. If you ever need to pull it back off it'll probably take the balance tap leads with it but hopefully you'd never need to.
For longevity I'd try and get hold of some silicon wire balance taps. Those PVC ones can be a bit brittle and aren't as tolerant of being flexed around. In Rodney's case atleast this shouldn't be an issue once boxed up,but it depends on how he plans to balance it. I'm using 36 pin centronics plugs now (pictured HERE on my fighter ) which are good for up to 30S and won't be looking back. The ease of connection is so much better than DBxx and there's minimal chance of being able to short circuit it.
For cell protection lately I've been using thin perspex taped at the corners to essentially make a box but I recall someone mentioning a while back about using self adhesive lino tiles. That sounds like a quickand easy option for basic protection without increasing the size too much

Thanks for the link Gregory. I've seen stuff like that on ebay but I'm after something thicker like the hobbyking stuff.
I think Gary Goodrum used to have it on his site for 3x6S packs wide which is exactly what I need but it seems he's left the ebike scene.
The thin stuff like that which comes on standard lipo packs is better than nothing but it offers little abrasion resistance.
BMS battery sells it but I don't feel dropping a few hundred on a whole roll of it!

[Rodney64]

Hyena, Hopfully the resistor was put in. Purchased them online overseas

[Rodney64]

Chris guess what my motor has arrived and ready for testing. 8.2 kilos

[jonescg]

Nice. Some time when I get back from over east I'll get you to bring a controller over and we'll wick it up.

Currently sick at home on the couch I get to infect a whole plane full of folks tomorrow. Yay.

Looking forward to driving the C-Rex home though.

KiM - Happy to place an order for more cells for your pack. Send us a PM when you're ready and we can get some more cells in. They are popular - on back order again!