Cyclone 4 - Going Lipo !

May 28, 2011

So now that the Prismatic LiFePo4 cells have given up the ghost, it's time to get a fresh battery for the Bike-E !

Below is the 24v 12ah LiFePo4 pack, beaten and battered..

Below, notice the smashed up corner, i'm told this pack came off the bike while at running speed and hit the ground, was then driven over by the rear wheel !! hehe.. nicly rounded corners !!

The above pack was up to the job, but 12ah ( Amp Hour ) is not much range if you play hard without alot of pedaling, so this season after some discussion, the Bike-E is getting a Lipo diet !

Zippy Flightmax 6 Cell 5ah 30C

These packs are commonly used in RC airlplanes, 6S ( 6 cells in Series ), gives a voltage of 4.2v x 6 = 25.2v fully charged and 3.0 x 6 = 18v fully discharged.

I would have liked to build a 7S pack for a bit more voltage, but nobody make those so i would either have to buy 4S and 3S packs and put that in series, just alot more wires and connections that i prefer avoiding.. so 6 Cell it is !

Each pack is 5ah, so 5 of them in parallel means 25ah, 5 packs were ordered just in case one arrived with a bad cell, Hobbyking does warranty their packs but shipping them back to china is not worth the expense, i figured that worst case scenario i could make a 20ah pack and hack up any bad pack myself and make a 7S pack for the bike, but given that all packs arrived in good condition, we can make it 25ah for now !

Next, like all rechargable batteries, Lipo requires proper charging equipment, i've had dozens of chargers over the years and a quality charger is the most important thing you can do for a happy battery pack... a charger that over-charges your pack will seriously cut into the number of cycles you will get from a pack, a charger that stops short is robbing you of range and maximum potential from your pack..

On that note, below is an iCharger 3010-B and a MeanWell SP-480-24 power supply :

The icharger is the best charger i've had the pleasure of using so far, have been using one for over a year on an almost daily basis to charge everything from Lead to Lithium, single cells to 10 cell packs, it does it all and stays cool..

The charger needs a power supply, most RC chargers are made to use out in the field and be powered from your car battery ( 12v SLA ) but the 3010B can take anything from 4.5v to 38.0v .

This is very convenient because the charger can be powered from a 24v power supply, and i happen to have an extra, i got 4 of these MeanWell power supplies on ebay a while back, they usually cost 80$ each but i got 4 for 80 !!

Cut a PC cable and crimped ring termincals

Soldered and shrink wraped

The charger's Input wires had banana plugs, but they do not include the male ends with the charger, so i removed them and installed Anderson Powerpoles

The battery packs arrived with gold Bullets,

I sat and looked at these for quite some time before finally deciding to cut them off and crimp andersons, yes they are nice and gold and i'm sure they carry plenty of Amps , and they twist around easily to relieve stress on twisted cables, but the open end nature of the bullets means they are dangerous, if the + and - wires cross on any given pack it will result in sparks, and i've had lightning in my office before, no way, andersons it is !

After individually ballance charging all 5 packs so that every cell was taken to 4.20v, i series connected 4 of the packs and drained them for cycle 1

( I had to leave the 5th pack out of it because it would be too much voltage for my Light Bulb Discharger )

Bright !

End of Cycle 1 = 5ah !

Cell number 2 of pack 2 is the weakest of the group :

So now time to recharge !

Below, you can see my 100v Norco Chaos using this setup i can charge all 4 packs at the same time to 90% and then top them off and ballance using the RC charger, saves time !

May 30, 2011

Since i have to cycle these packs a number of times to weed out any possible runts, i may as well put that energy to use and have some fun in the process !!

Taped up 3 packs and hooked it up to my e-BMX

Fun little bugger this bike is !!.. with 3 packs ( 18 cells ) and 72v, she goes 70 km/h !!

The 30C zippy packs have noticably stiffer voltage than my 20C Turnigy packs !!

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June 2, 2011

Got my Lb of Kester 44 today !!.. Just in time before the Postal Strike that kicks in tomorrow !!.. ugh..

I had a small spool of this stuff a while back and ran out, really missed after having to go back to the other brands.. it melts and flows well.. i like this stuff !

Now it's time to decide on how to build this pack !

Either a strip of 5 in a row..

or.

3 and 2, one thing i noticed on the Chaos is that these Lipo cells swell and contract while charging and discharging, this is normal, but the more cells you line up the bigger impact it has on the end cells causing pressure .. With that in mind, i'm tempted to build the pack in 2 sections..

Lined up next to the old pack, 5 in a row would be slightly longer than the original pack.. but slimmer..

2 wide would be slightly wider than the original, considering i still have to add a layer of PVC panels to protect the packs..

Notice how much more energy you can get from Lipo vs Lifepo4..

Original 24v 10ah = 240wh ( watt hour )

Lipo 24v 25ah = 600wh !!!

That's almost 3 times the energy, in less space !

 

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June 5, 2011

Last night i moved to the garage and started cutting pvc plastic.

I've tried the table saw, not ideal for cutting little pieces ( dangerous ) .. and the hot melted plastic pieces flying off the blade at high speed, hurts !!!

So i've been using a scroll saw, with the right blade ( 18 tpi ) and dialing in the speed so that the cut says open and does not re-melt behind the blade, works pretty good !.. it's difficult to get a perfect straight cut with such a thin blade, but by grooving the pvc panel with a sharp awl ( pictuer above ) it creates a canal for the blade to follow, turns out ok.

I cut some 53mm strips to seperate the packs, and stuck the packs together with industrial double sided carpet tape..

I discharged the pack to 50%, so that they loose their swelling effect from a full charge, then using wood clamps, compressed the packs slightly and secured them with Nylon Filament tape.. this stuff is incredibly strong, and will not strech..

3 down.. 2 to go !

Chilly night, just the way Sandy likes it.. keeping a watchfull eye on Quality Standards..

After a lot, i mean.. A LOT of deliberation, i settled on this configuration :

I was going to have the 2 packs ( 3 and 5 ) vertical as well, but it made routing the wires a problem, this way should work out better..

Next up.. soldering !

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Back in the office, got the wiring tools out

Using Anderson Powerpole 30 amp connectors on 14 awg silicone cable, this cable is very nice to work with, extremely soft and flexy, expensive, but worth every penny, the only place i've been able to source it is from hobbyking.com

 

Fired up the Hakko station and my 3rd helping hand clamp..

Andersons crimped properly on this type of wire do not need to be soldered, but since this pack will be boxed up and somewhat sealed, i am taking no chances and soldering them anyways.. Just enough to bond the strands to the PP30 connector, having the wire vertical insures the solder will not flow onto the spoon section, wich makes it very difficult to click them into the housings, and makes a poor connection as the spoon section becomes stiff and will not spring and bend to make a good contact with it's mate..

Starting with the Positive + power wires first, I crimped and soldered a PP30 tip on the end of my spool of wire, clicked it onto it's battery lead, pulled the lenght i wanted and cut the wire, then moved onto the next.. repeat 5 times.

And the Negative -

I need to cut all the wires at the tape section, and solder them all together along with a big fat 10 gauge wire for discharge.. !

And .. then work on the ballance leads..

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June 6 , 2011

After crimping and soldering all the anderson connectors, i snapped all the wires into their pack leads and taped them so that the andersons will be oriended properly and not twisted once soldered together, then cut some strips of copper to band the 14 gauge wires together..

Above, notice the 5 x 14 awg wires, and the larger 12 awg discharge lead..

Then, repeat for the negative side

And soldered

Next, before going any further, all the packs have to be charged to the same voltage, before hooking them up in parallel, this is very very very important !!

If you hook up an empty pack with a fully charged pack, the energy from one pack flows into the other at an un-controlled rate ( limited by internal resistance of the cells, and the imballance level ) .. long story short it's bad... all the cells from all the packs should be within 0.05 volts or so ....

Getting all 5 packs fully charged and ballanced, takes me to 11pm !.. tomorrow night, the ballance lead harness !!

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June 11, 2011

Alright, life is getting in my way and this is overdue, but it's saturday and i'm back at it !

Below, I have to turn these seven pigtails into a ballance lead harness .

Space is at a premium and after much thought, i decided to use the male side of these pigtail extensions from hobbyking.com i cut the female side off as they seem to be fairly worthless, darn things work 3 or 4 times and then the charger starts to give you warnings.... the female ends on the battery packs are good, these are higher quality and always hook up properly.. but the extensions.. not so much

After using hot glue on the connector ends to keep the pins in place and provide a grip section to pull them apart without having to use your fingernails.. ( I really dislike HXT connectors, but they are compact, ... ... with the hot glue they are ok.

The Glue !

Ok, so since the pack is made of 2 sections, i split the ballance leads, hooked up pin 1 of each connector to each other, pin 2 all in a group, repeat for all 7 wires..

The reason for doing this is that the all 5 packs can be charged and discharged and monitored in one shot. cell 1 from each pack are in parallel, cell 2 of each pack etc are all acting like one large cell ( 5 x 5ah = 25ah ! ) As far as the charger is concerned, this pack is 6 cells ( 24v ) and 25ah .

Above, next I cut both ends off the longer extensions and soldered the color combination in the right order, one color per cell group.. heat shrink over the solder joints.

Then I twisted the 2 sections and crimped on andersons, strip back double the lenght of the anderson crimp pin, and fold it in half making a bulge at the end that grabs on the connector, using PP30 tips.

Usually I don't bother soldering andersons, but for this application i want to be absolutely sure that nothing comes loose.. so crimped and soldered the buggers..

And there they are, harnesses, DONE !

That's a total of 29 Andersons, and 37 soldered connections !

( Yes, i know , the negative discharge wire is RED, the black 12 awg wire was on backorder at hobbyking and i had to substitute for red, i will cover the wire with black shrink to prevent accidents !

 

Next, it's time to secure the 2 sections into one brick, first i used filament tape on the ends of the packs to create a flat surface and add a layer between the pvc panel and the tape, should i ever have to split this thing the double sided tape will give before the nylon filament tape, and hopefully not ripping the cells in the process..

Then, used a big fat strip of double sided tape

filament, tape, pvc,tape, pvc, filament, plenty of strong layers !

Then, after double checking my cell voltages and quadruple checking my wires, with so many connections the possibility of an accident is great, one wire in the wrong place and it all melts into a puddle of goo !.. not the type of work you want to do when tired !

This part i've been thinking about for the past 2 weeks, have changed my mind many times, but finally settled on what i think is the best solution.

Below the 2 vertical packs, i cut a piece of pvc and secured it in place with a piece of angle aluminum and double sided tape, i will then drill holes thru both layers and bolt it securely in place.. same thing on the top right hand corner, no wires run in this area so i don't mind having metal pieces, on the top left and bttom right there is no room for nuts and bolts so i bent 2 strips of PVC, using a heat gun and some pieces of angle iron, same technique as this :

 

 

I still have to trim the ends and cut a section for the ballance leads, but this gives a rough idea of what the final pack will look like

The 2 pieces of tape on the bottom are just markers for the ballance lead position, it's a mighty tight fit, but it will fit !

Took some digging, but when the local Radio Shack closed down, i picked up a bunch of misc. parts, I found in my stash some threaded screws that fit perfectly inside the anderson housings, they will act as roll pins and prevent the blocks from sliding apart, and secure them solidly to a piece of PVC that will bolt inside the bottom panel.

One of the challenges is to find a way that i can remove the parallel harnesses for winter storage, if i use tape all over, it will be a real SOB to get into it come november ..

So.. a few more holes, nuts and bolts, and she's just about ready to go !

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June 16, 2011

Above, after alot of searching thru my stash of parts, finally found my gromets ( little round black things that go over wires

And I actually found my Nut-Sert gun !!!.. I really wanted to avoid any possibility of metal pieces getting loose inside the pack, and have gone thru alot of headaches to insure minimal metal parts in there, the nut-serts are like revets, using a special gun you crimp them on and they stay put, allowing a threaded section behind, kina like water bottle mounts !!

I then cut a piece of PVC and drilled the holes between the ballance lead andersons so I can bolt them down. This will be glued and bolted to the bottom section of the box, flush with the side panels.

It's like putting together a puzzle, you have to make sure all your holes are drilled, I's dotted and T's crossed before assembling all the pieces, taking stuff apart to backtrack is not cool and wastes materials. ... Think twice, do once. !

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June 18, 2011

Over the last 2 days i've been putting the finishing touches and bolting it all up..

A few less pictures of the process at this point because i really have to put the camera down and get my butt in gear to finish this, I spent alot of time on this pack and i learned a lot along the way. a 2x2 block would have been a much easier build, but wedging that 5th pack in there was worth it simply for the extra capacity.

I cut a few pieces of aluminum angle, installed 2 Nut-Serts on the side of the box i plan to leave accessible.. and after digging thru my nuts and bolts pile, i decided on rivets for the other side, nuts and bolts and washers and spring washers etc all add weight and this pack is not getting any lighter by the day as i keep adding more supports and layers of protection..

Above, double sided tape holds the aluminum to the plastic panel, 2 rivets clamp it on there hard, and i covered the back with hot glue to cover any possible sharp edges.. and to keep the back sides of the rivets in place should they ever, for god only knows what reason, come off..

Similar treatment to the ballance wires, going into Anderson PP30'a ! crimped and soldered, screwed, hot-glued and riveted.!

A generous amount of industrial grade double sided tape !

This stuff will allow me to pull the side panels off, but not without a fight !!

Next, ( and this is where there are less pictures, and more work ! )

I made the most awsomest ballance wire extension ever out of 3ft long, Turnigy 14 awg silicone noodle wire with anderson PP30's, good thing with andersons vs HXT connectors is that they are nice, rugged, durable, and made for repeated connections, they will never see more than 2 amps ! lol .. but has a nice solid feel to it instead of flimsy RC weight weenie stuff.. ( witch does work btw, just requires use of fingernails.. i have a stressfull day job and have very short nails.. )

So, andersons are good, but they pose a certain problem, 2 connectors are easy to plug and un-lug, 7 of them, not so much.....

The dovetails on the blocks tend to break apart of they flex too much so I had to find a way to secure the blocks..

I took a row of 7 anderson Blocks, clamped them into the bench vice and with a hack saw i cut the ends off..

Then, took another piece of that aluminum angle stuff, cut legs into one side to fit into the blocks from where the wires would enter..

And :

The top row of andersons keep the bottom row flat, their faces sit flush with the box, the angle aluminum provides something to grab, and the whole thing works fairly well, it takes a bit of wiggling to line it all up, but as it wears in it will loosen up.. provides a nice solid connections however, no " Ballance Wire Disconnect " errors from the charger with this sucker !

The Icharger 3010B has an 11 pin ballance port that goes into a multi-pin flat board, see below :

I was going to cut the 11 wires and crimp andersons on there, but decided to tap into the 6 cell board segment, this allows for Mr.A ( the BikeE owner who this is going to ) to use the charger in stock form and work with any and all batteries he comes across, a shame to have such a nice charger and not take advantage of it !

And with that, the pack is pretty much " Done ! "

Or, at least operational !

I plugged it into my LBD for a quick discharge, the pack went from 25.0v to 24.9v when i hooked it up to the lights !! how's that for stiff voltage ! hehe..

At the 2ah mark, all cells still above 4v, i took it down to 12ah and cells were still at 3.9xx volts !

Then, after a 12ah discharge, time to test the charger and power supply at higher power, i used them to ballance charge the individual packs initially, at 5 amps, but now that the packs are in parallel for 25ah, i can bump it up a few nothes !

Below, 10 amps, at 8 minutes i've put 1.4ah back into the pack !!.. and everything is bone cold ! sweeeet !

And the Cycle Analyst confirms that the calibration is good !

10 amps ? = Check !

Now, the charger will allow for up to 30 amps !!!..

This pack can and will take that much charging power, and more ( cells rated at 2C recharge, so 25ah = 50 amps max ! )

However, for now, it's prudent to keep things below the radar and allow for a few cycles while monitoring everything for heat and all that.. good news here is that everything is well within limits and staying cool !

The MeanWell power supply is rated at 24v 20 amps, that's 480w max, this means Mr.A can charge at up to 20 amps being limited by the power supply, a 2nd supply could be added to double the power, but a 10 amp charge means 20ah in 2 hours, very respectable !

20 amps gets the job done in 1 hour

30 amps .. well you get the picture..

( The pack is 25ah, i set the charger to stop charging at 4.17v per cell ( Instead of the maximum 4.20v ) , giving some headroom and also this is good for cycle life.. In doing so you do limit the capacity a bit but not that much ( estimate 1 ~ 3 ah ) . By never using more than 20ah from a full charge, there will be reserve energy in the tank !

So, that's it for tonight, it's past 12 and time for bed !. .next update will be pictures of the pack mounted to the bike !

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June 20, 2011

Got this picture yesterday:

Well, ain't that nice !

I totally missed the chainline position, woops.

However, the solution is simple

The power wires exit the back instead of the front, but the wires from the motor are long enough to reach without any extension cords, will do for now.

Once the bike runs for a few weeks and all is good, i will build a key or switch with lights that will add onto the box..

 

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For now, there will be no BMS on this pack, but there will be a Hobbyking ballancer to display all 6 cell voltages while riding so it's a manual BMS for now !