Bearings - early thinking, since changed (see final)

NOTE ... these are earlier possibilities, discounted because of price, and unnecessary difficulty of mounting.

Go the easier, cheaper solution (except that bearings have to come from the U.S.).

Bearings

• From http://www.smallparts.com.au
• Bearing Part B4-TB. In stock. ID 20mm, W 24.7mm, 47mm OD $20.71
• Pressed Housing Part PFL-4, 90mm x 67mm, $8.50

31/07/2009 Achievements

Electric Go Kart

• Worked out about bulk-charging (fast charging) ...

......-> Need power supply that will not exceed maximum amperage ...

......-> ... and will not exceed maximum voltage ...

......-> Need Voltage cut-off per cell (ie parallelled cell) that will cut of early ...

......-> ... means not full capacity, but safely charged, and very very fast !!

......-> Then, regularly, put on balancer to "fix up" balances growing in the pack.

• Working on design of Kart, trying to get brakes into back frame (difficult to fit them).
• Research on bearings.

Latest chassis drawing

Lots of alternative drawings done. This is (I think) the best of the bunch :-

Lipo battery connections

My question to "Methods"
(an expert on http://endless-sphere.com/forums)

mikehains wrote:methods,I have read many of your posts, and it seems you are one of the most experienced with Lipos.My new 8 x 18.5v 5A Lipo Turnigy "Bricks" turned up, and I want to wire them like this:My question is ... do you (with your Lipo packs) leave the balance connectors paralleled while using them ? Or do you only connect them in parallel when charging them ?I know I've seen posts about this, but it is your experience that I'm keen to hear.Kindest

Response from methods

Re: Zippy Flightmax / Turnigy lipo testing
Sent: Wed Jul 29, 2009 11:36 am From: methods To: mikehains

That is exactly how I do it and I keep them paralleled all the time.I think you are on the right track.

You want to keep them in parallel all the time for many reasons, not the least of which is the risk of constantly connecting and disconnecting the JST-XH connectors. You want to connect everything once and leave it. I promise that if you can make a mistake (like plugging one of the upper balance connectors into one of the lower) you will eventually. This is not to mention the wear and tear on the connectors. I cant tell you how many times I have smoked up balance taps due to stupidity.... You also want to keep them connected so that you can run cell level protection while you ride.

At a minimum you want to run a pair of BM6's so that when the first cell hits LVC you will get beeping.Later when you run cell level LVC protection you will want them all tied together as well.

I have put over 3,000 miles on my collective bikes in the last year or two and they are all run in this configuration.

Please be very careful.... Many times I have had my cells connected at the cell level and forgotten. I then tried to convert a pack from something like 12S 4P over to 24S 2P and shorted the packs. No damage but lots of smoke and fire.

Just be very deliberate whenever working with this many cells. It really is a dangerous amount of stored energy. If you keep the JST-XH taps you can get the JST-XH extenders I pointed out and use 7 pin JST-XH board connectors to hook everything together. You know those little perferated boards at RadioShack that have the copper traces on them already? Those are perfect for JST-XH board mount connectors. This way you dont even have to make a big double-Y cable.

-methods

29/07/2009 Achievements

Electric Go Kart

• Discovered (from "methods") that it is safe to wire all the EV batteries together (balance taps together) and leave them like this. This is a huge benefit, for charging / recharging etc.
• Started work changing the chassis design for the Kart, to be shorter wheelbase.
• Continued on design. Created 6 alternative designs. Selected the best, that works properly (boys trying to kill it) and looks the best as well.

28/07/2009 Achievements

Electric Go Kart

• Cleaned up my study (junk away)
• Further worked on the 'bad' battery. Had to turn it off to leave for work. When I left, voltages were: 4.20, 4.20, 4.19, 4.18, 4.17
• Brakes turned up (hooray ! perfect !)
• 10K slide potentiometers turned up. Don't know if these are the right decision. They are quite "sticky" (ie they do not slide incredibly easily).
• Chased questions about balance connectors staying on during use - see http://www.rcgroups.com/forums/showthread.php?t=932319&page=24#post12751921
• Also PM'ed methods at endless sphere.
• Worked on accelerator.
• Asked boys (they prefer sliding to twisting).
• Got sliding one to slide more easily.
• Tested with controller and batteries. Discovered: (a) circuit diagram is wrong (max 8volts - fixed that), (b) sliding Pot is only effective for 1/2 of distance ... and (c) does not allow very accurate control of speed (movements of pot are too small to make sense when driving).
• Therefore - ordered twist grip controller from Oatley Electronics, designed specifically for this controller (is probably hall effect).
• Finished charging all batteries. Sorted out the "sucky" one.

27/07/2009 Achievements

Family

• Woke up early to drive Jack to basketball.
• In the afternoon, when I got home, did a little bit of playing with the batteries ... and then stopped and played basketball with the boys until it got dark.
• Stopped with batteries to watch "Top Gear" (the Space Shuttle program) with the boys. Extremely funny.

Fitness

• Woke up with raging cold. Therefore, no run (don't want to make it much worse).

Electric Go-Kart

• Decided accelerator must be like a brake - handle that is pulled by fingers towards the steering wheel, and can be let go, with spring effect (immediately off).
• Batteries turned up. Hooray !!!
• Tested CellMeter-8 "Fuel Gauge". Properly tests batteries. Turns on to test, and directly to "Fuel Guage". The "Fuel Gauge" seems right. Testing will show whether it is any good or not.
• Tested Chargery BM6 cell tester / alarms ... They measure beautifully.
• There is a slight difference between CellMeter and Chargery. Tend to believe the Chargery.
• Of the 9 batteries that arrived, 8 are perfect (all within 10mV). One is slightly out of balance. After a short balance attempt, cells at:
• Plugged packs in to charge. Pack #1 - quick to charge, and very well balanced already. Pack #2 - not very balanced on charging. Took at long time to balance.
• Next 2 packs, charge beautifully and perfectly balanced. No problem.
• Worked on balancing the difficult pack. Disharged to 4.00, then discharged to 3.98. Closer.
• Then simply plugged into to charge and balance and left it.
• Had to turn it off when going to bed (2 cells at 4.20, 1 cell at 4.11). Much closer, but still not right.

Other

• Sorted out the "hire car" problem, for getting my car fixed.

Note about charging Lipos in large series

Reproduced from here: http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=4432&start=450#p124684

-methods


P.S. FYI for anyone considering using a power supply for charging:


* Every power supply is different. Some dont like the voltage being drawn down
past the set point.
* Must have an accurate DMM
* Must have an accurate inline current meter
* Must have capability to make multiple high power Series Parallel wiring
harnesses
* Must have capability to make complex balancing harnesses
* Must have (hard to find) parts for above
* For best results packs should be charged in true Parallel
* Buy only 1 size of lipo packs, i.e. 5S or 6S. Dont mix and match
* Attach all lipo in parallel, both the power lines in parallel and ALL the
balance lines in parallel
* Hooking all the packs in parallel will somewhat self balance the cells
* Hook one 6S balancer to all the packs, start balancing
* For starters set the power supply to charge all the packs to 4.1V instead of
4.2 for an error margin
* Hook an inline current meter like a WATTS UP to check voltage and watch
current
* Attach the pack and watch the current close, get ready to pull the plug
* Current should go to the max rating
* Voltage will sag to the pack voltage
* Voltage will steadily rise
* When you get to within a volt or two of the set point (HVC) the current will
drop very rapidly
* Once you get it worked out then you can charge to 4.2V/cell
* Check the leakage current of your supply. Mine is 300uA so once it gets to LVC
it stops charging
* If your power supply is cheap it may have mA trickle which could be a problem
if you leave the pack on
* Dont charge overnight. It should only take an hour or two so KEEP AN EYE ON IT

** GANGSTER LEVEL TWO **
* Once you have the hang of it, you can charge in series
* To charge in series you MUST have a way to balance.
* Balancing individual packs will NOT WORK

NOTE: for these methods you need BOTH a power supply for charging in parallel
(or any 6S RC Charger) AND a charger for charging in series.

I would suggest that only "RC People" with Lipo experience try this. Those
people should have a 6S balancing charger already.

Use that to charge the packs in parallel.

** I use the 24 Cell DIY balancing board that Fechter, Gary, and others designed
for my packs and I only have the high voltage (100.8V) charger. I never go to
parallel.

Electric Cart Chassis drawing

26/07/2009 Achievements

The Plan

• Weigh all the parts.
• Make mock-up accelerator pedal.
• Run 20 minutes

Family

• Early kicking practice with Tom.
• Watched Tom's game (he scored 29 points by himself, 3 tries and 7 conversions, 7 from 7). Record game. Didn't play last 5 minutes (substitution on). During that time, the other team ran in three tries.
• Then was Touch-line ref for Jack's team. Jack had an incredibly strong game, again. Very strong play as forward. Constantly driving and holding out the other team.
• Lunch with the boys.
• Went down to Poppy's and ran the Quad bike for 2 hours.

Fitness

• Run as touch judge for the game (not very hard to do).

Electric Go Kart

• Made a mock-up wheel.
• Made a mock-up chassis.
• Completed sketch-up drawings of the chassis.
• Got a 20mm axle from Poppy.
• Realised the speed calculations were potentially wrong.
• Started to file down a cog - can be filed ! (but not drilled).
• Discovered (by research) a motorbike with 2 x 650W geared motors MY1010 (ie 1300watts, versus 750 watts, but same gearing).
• Bikes show larger sprocket simply welded inside 14tooth sprocket on motor.
• Geared for 32kph, 1300watts gives slingshot acceleration.
• Kart geared for 16kph should give same acceleration.
• 14/32 gearing shows 18kph, on 19" diameter wheel.
• 10/32 gearing shows 13kph, on 19" diameter wheel.
• Both of these speeds are probably right, for around the house. Top speed might be slightly too fast.
• These are "good" speeds, allowing motor to work at a sensible pace.
• These allow motor to be efficient at top speed, and given that most of the time it will be accelerating or decelerating (for corners), it won't be too highly geared for use around the house.
• Gearing for higher top speed will stress the motor for take-off, and regular accelerating.
• Gearing for higher top speed will also reduce life of batteries (inefficient range for motor).
• Higher top speed will require a kart created for higher top speed (ie safety, width, braking, padding, roll protection, suspension, etc).

.....When the current electric go-kart gets too slow ...

• Make a cool 60's style "dragster" with 2500watts, and Alltrax controller, and Lipo's (burnouts, and wheelies ... but limited range).

Go Kart Brake

25/07/2009 Acheivements

Electric Go Kart

• Went to quad shop.
• Purchased sprocket 14teeth (same as motor) that will go perfectly over 17mm axle.
• Looked at disk brakes and hydraulic brakes (too expensive !)
• Yes - they have tie rod ends. But too large ! Just tighten those I have.
• Disassembled front end, ready to make into electric Kart.
• Measured king pin bolt - need 10mm shoulder. Maybe from Kart shop itself.
• Spoke to Poppy about steel supply. He has 2m of 20mm precision rod. We should go to steel shop together, to see what they have.
• Analysed the brake required. Purchased this brake on eBay.

23/07/2009 Go Kart Rear Wheel

48.2cm tall, 17.7cm wide

24/07/2009 Achievements

Electric Go Kart

• Calculated that chain is "420" (ie 6.35 width between plates, 12.7mm pitch)
• Looked hard for, and found, sprocket for the electric motor - namely: http://tncscooters.com/partsdb.php?type=ES
• It is called a "D-Bore" sprocket.
• Decided axle (17mm steel) ... because it is too much trouble to cut "keyways" in expensive axles ... which cost $150 new anyway ... and even if purchased second hand, have to use expensive hubs and carriers for everything (crazy !).
• Thoroughly welded is going to be plenty strong, and reliable.
• Also - get to use little sprocket (14 teeth).
• Worked out how to weld round wheel bracket to rear axle.
• Spoke to Poppy about this, and got his approval to do this.

Go Kart shops brisbane

List of Go Kart shops in Brisbane

• Northside Go-Kart Supplies 225 Zillmere Rd Zillmere QLD 4034 ph: (07) 3265 2774
• Brisbane Kart Supplies - 32661475 - 341 Melton Road NORTHGATE QLD 4013
• Global Kart Centre - 32165888 - 19 Virginia Street VIRGINIA QLD 4014
• Sodikart competition - 38652525 - 33 Beckman Street ZILLMERE QLD 4034
• Podium Motorsport (CRG only) - 33419041 - No address (must call) - http://www.podiummotorsport.com.au
• Kartsport Supplies Unit 2 31 Darnick St, Underwood, QLD, 4119 Phone number: (07) 38414933
• Arrow Karts 20 Mudgee St Kingston QLD 4114 - ph: (07) 3804 3244 http://www.arrowkarts.com/

23/07/2009 Achievements

Achievements

• Decided what to do about steering, and about rear drive (see pic below)

• Planned my day.
• Started well (got stock into plan).
• Email from http://www.hobbyking.com/ ... that batteries etc have been shipped ! (hooray).
• 7 to 45 days to arrive.
• Thought carefully about rear end of Kart.
• Out of office and went to Capalaba Quad shop (looking at wheels, etc) ... better understanding of available wheels etc.
• Listed Go Kart shops.
• Won the wheel that I wanted on eBay for $15.00 (plus postage). Hooray ! See the picture of the wheel here: Wheel Picture
• Now, extremely likely, use GoKart axle with wheel.

Electric Cart objectives

Electric Go Kart Objectives

These are in order !

1. Around the house easily.
2. Stops fast.
3. Strong (100kg)
4. Long running (35 mins +)
5. Lightweight
6. Cross country
7. Elegant
8. Perfectly finished
9. Easy to make
10. Quick to make

22/07/2009 Achievements

Achievements

• Jumping 18x (ski training)
• Planned work, and worked very effectively.
• Read through all the applications received (for new job available).
• Carefully calculated the maximum I would eBay bid on wheels + broken quad ($159).
• Rang the Mt Gravatt mower shop and asked about single rear mower wheels (none ... and hard to get, gave me Ph number of "Kelvin" (0418 475 267) to try ... apparently he has a large shed full of old gear.
• Succeeded in buying wheels and an old (clapped out ?) Quad. Going to pick it up (with cash) this afternoon at 5.00pm, from 11 McDonald Street Jimboomba (Mark Jones)

• Picked up the wheels.
• <<<>>> Never buy second hand from eBay, without an inspection.
• Bike is crap. But actually, it is better than the wheels.
• Learned -> 50cc Chinese bikes have tiny little axles. Too small to hold an adult.
• Learned -> Exactly how the rear axle on the tiny little bikes works (in truth, could probably only have learned by dismantling one).
• Worked on "new possibilities" (see below)
• Re-entered objectives (see below)
• Searched for bearings for front wheels (26mm OD 10mm ID 8mm width).
• Total $13 for chinese, delivered, via eBay.
• Found a very cheap possible wheel.
• Discovered GoKart bolt pattern (rear) is 58mm PCD.
• Cheap eBay (new) wheel is 85mm PCD ... therefore, steel flange will fit !

New Possibilities:

Question: Can I use the rear axle ? NO ! Doesn't work !

Question: Can I use the front steering ?

Maybe ... but only if I remake the knuckles so that they have stronger stubs ... so they bear weight better.

Question: Can I use the front wheels ?

Maybe ... but only if it is possible to put new bearings in them, so that they can run with the larger axles

See "Electric Cart Objectives"

Planning #1 - the fastest way to get a Cart

Imagining that money was no object

..... Things to buy

..... -> Cart / Buggy (eBay $750)

..... -> Steel ($25)

..... -> Rear 'flash' wheel ($55)

..... -> +++

..... Total = $ 1000+

.....Action steps

• Buy a working cart or Buggy
• Cut down the frame.
• Buy an ATV rear wheel, blank (without studs cut).
• Have stud holes cut to match Cart hub.
• Install Cart hub in shortened axle

Planning #2 - the cheapest way to get a Cart

Imagining that little or no money was available

..... Things to buy

..... -> Bearing for front wheels (eBay $13)

..... -> Bolts ($5)

..... -> Steel ($15)

..... -> Rear bike wheel ($5)

..... -> Rear bike gear ($25)

..... Total = $ 63

.....Action steps

• Get new bearings for front wheels (eBay $13)
• Weld in M17 bolts (or M16 bolts, or 16.5mm precision rod) to fit.
• Cut the frame down (from steering post back)
• Weld in two straight steal beams to the back.
• Put in a 16" bike wheel, with rim brake ... and adapt gear to correct pitch

Planning #3 - spending some money, not too much

Imagining that little or no money was available

..... Things to buy

..... -> Bearing for front wheels (eBay $13)

..... -> Bolts ($5)

..... -> Steel ($25)

..... -> Rear 'flash' wheel ($55)

..... -> Axle bearings ($20)

..... Total = $ 118

.....Better because

..... -> Great rear wheel

..... -> Disk brake (upgrade to hydraulic ?)

..... -> Excellent TOUGH gearing.

..... -> Same or better than the adapted "Buggy" ... with no waste !

.....Action steps

• As for #2 above ... except ...
• Buy a flash rear wheel ($55 eBay ??)
• Cut round plate steel (to be flange)
• Drill centre hole.
• Perfectly drill other holes (for wheel mounting).
• Perfectly weld (test on lathe, for straightness) to 19mm precision rod axle
• Also weld on disk-brake rotor holder
• Also weld on gear
• Weld disk brake rotor-holder onto axle
• Cheap disk brake to back wheel.

21/07/2009 Achievements

Achievements

• Completed eBay searches.
• Planned work, and worked very effectively.
• Finalised battery pack + cooling ...
• ... ali brackets, on risers, with seperators
• Finalised battery wiring (crimp connectors, insulated)
• Searched (hard) for alternatives for wheels etc.
• Advertised for new staff member.

Ordered batteries

Chassis Design

Chassis options:

• Steel [too heavy]
• Aluminum [welding ! no fun]
• Fibreglass [same weight as steel, for strength]
• Carbon [what about crashes ?]
• Carbon / Aluminum
• Carbon / Steel
• Carbon / Kevlar ... this is the decision !

Chassis Design

20/07/2009 Achievements

Achievements

• Searched eBay (kart, quad, buggy).
• Located (again) diagram for battery wiring: http://scriptasylum.com/rc_speed/_lipo.html (or here: http://www.offshoreelectrics.com/lipo.php) ... and also see here: http://www.rcgroups.com/forums/showthread.php?t=932319
• Jumping (18x) for ski holiday fitness.
• Plan day at work, and complete plan.
• Worked out chassis design (see here: http://hainsprojects.blogspot.com/2009/07/chassis-design.html)
• Read something (not computer !)
• Read through parallel wiring (rcgroups thread).
• Carefully researched wiring (and plug) possibilities.
• Decided wiring should all come out one end ... for easy connections with each other ... and to easily connect together, and to controller (and other switch-gear).
• Decided batteries should be encased and protected, and mounted longtitudanally ... with the "sides" (left and right) with venting ... so that if things go "boom", the fire etc is directed out the sides, not forward and backward.
• Decided the battery pack should be "wrapped" (including 1 layer Kevlar) North/South ... so that no explosion in battery pack will hit driver.

Plan

• Work out how to solder / wire the power packs together.

19/07/2009 Achievements

10K, 75mm sliding potentiometer

Achievements

• Soldered up the "Not" switch. Got it to work perfectly (all wiring ready to go). Now, all I need is for the "non-return" valve to turn up (from the US) and I can mount the whole of the vacuum gear ready to go.
• Also tested out the motor. At just 15.6volts, it runs like an absolute dream. Very quite, and very smooth (and incredibly powerful).
• Researched making accelerator pedal (eg electric game pedals). Decided make self ... so that accelerator pedal matches the brake pedal.
• Found and ordered Potentiometer (10K sliding) for accelerator (from www.Futurlec.com.au).

18/07/2009 Achievements

Achievements today

• Tried simple Transistor "Not" gate. Didn't work.
• Tried Jaycar relay circuit to switch to "Not". Realised wouldn't work.
• Rummaged through shed, and got out old breadboard.
• Designed a "voltage divider", low wattage (but still not very efficient) to work a "not" on the SCR. So ... voltage is divided higher than 3.0v (actually, to 3.7v) so the SCR is normally on ... then if the vacuum switch sinks current, it basically short circuits the SCR (but through a resistor, so very low current) and turns off the SCR.
• It works ! Now just have to figure out how to solder it up "for real".
• Also did my eBay searches ... looking for the parts. Seems most likely that it will be the ATV ... because gokarts, even second hand, are too much money.

17/09/2009 Achievements

Achievements Today

Specifications for the rear bike wheel

• Decided "Pit Bike" rear wheel looks right.
• Decided Steel rails for side (stronger ... & fast to make)
• Decided would prefer rear wheel of at least 30cm (12in) diameter ("direct" speed 24kph 10:14 speed 18kph, 14:10 speed 35kph) ... preferably more !
• Decided must be at least 20cm wide tyre at back (8 inches) preferably more.
• Drive chain sprocket on one side, and disk brake on the other.
• This means axle must be "rotating", and "floating" (ie wheel slides on)
• This means cannot use standard ATV axle (too wide ... and cannot cut down +++ not 'floating' axle)
• Choices: (1) find a different kind of hub for ATV wheel, or (2) use Kart parts.
• Carefully considered options. Choices, in order of preference are: (1) Start with full cart, and adapt rear axles (with perfectly "floating" parts) to single wheel + create adaptor for ATV rear wheel; (2) Start with full "ATV Buggy" (ie already large wheels); (3) Start with Quad bike 125cc +, and adapt rear power to single wheel.

Timing now

1. Each morning, do "saved" search for: (1) Kart rolling chassis (no motor) for under $350; (2) ATV buggy with huge wheels, for under $300; (3) ATV quad 125cc ++ under $200.
2. Create accelerator (can swap the potentiometer)
3. Create vacuum electronics
4. Create balsa/fibreglass rails for future use.

16/07/2009 Achievements

Achievements today

• Motor turned up (hooray !). 750 watts. 36v 16A (which would indicate 500 watts)450rpm (geared). With sprockets, chain, and controller. Questions: will it be fast enough ? Will I need to double-up ?
• Checked out go karts as donors for parts (no good, too expensive).
• Found Chinese quad bike 49cc as donors (possibly very good).
• Made eBay bid on a second-hand chinese copy 49cc Quad bike (for the wheels, axles, brakes, and steering components). Only one second hand advertised in Qld.
• Researched and discovered the kids Quads have wheels too small.
• Thoroughly researched. Found great picture of 3 wheel golf cart (2 front, 1 large rear).
• Decided to do the same.
• Likely "Pit Bike" rear wheel.

15/07/09 Achievements

These are the things I did today:

• Learned that a 28Ah SLA battery, will last only 1 hour at 10A.
• Learned that 32Volts 20Ah equivalent to Lipo, will weigh 39kg
• For same power, in Lipo, you've got 5.2kg.
• For same power, in LiFePO4, you've got 7.6kg
• So SLA batteries are completely out of the question.
• Emailed Victoria at Headway, about buying 24 x 38120S cells directly from her.
• Checked Thundersky weight (32Volts 40Ah minimum, will weigh 18kg).
• So Thundersky batteries are quite out of the question.
• Learned that LiPo chargers can never be just "plug in !"
• Found a site with a guy using LiPo on a bike (too good result) = http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=11124&hilit=LiPo
• Learned that to charge ... just need power supply that won't exceed maximum ... then just connect balancers to balance taps of the batteries - see http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=10817&hilit=LiPo+charging&start=15
• If buying LiPo from HobbyCity, and any cell is out of balance, they will send a replacement. 1.0volt means cell is dead.
• Parallel the batteries for balance (critical !)
• Description of alternative charging methods: http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=9170&hilit=LiPo+charging
• It is crucial not to make the mistake of re-configuring the pack, in order to charge. See the photographs by a VERY experienced user, at http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=8554
• NEVER have any connections that need to be plugged or unplugged. Make things AS INCREDIBLY SIMPLE AS POSSIBLE !
• It is theoretically possible to use a Monster power supply, set at 40V ... with some kind of switch to turn it off when the current draw becomes small (ie charging done) ... and a permanent LVC system on the pack, which cuts power if voltage too high or too low on any cell ... and networked balancers.
• The "very safe" option, is to use Use 1 x 10S charger on 10S4P pack (just takes longer) - http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=10653 ... and it will just take a long time.
• NOTE ... set cut-off to 4.1 volts, not 4.2 volts, for up to 10x longer cell life !
• Need individual cell (for Low Voltage Cutoff or LVC) protection ... which can come from the Chargery beepers ... fitted to some kind of "trip" switch that stops the thing from running ... needing a reset - see http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=9229
• Chargery supplier online = http://stores.shop.ebay.com.au/acrc_category1179241018_W0QQ_fsubZ1179241018QQ_sidZ167758548QQ_trksidZp4634Q2ec0Q2em322
• Charger is 749g, so might conceivably stay permanently connected on the cart ???
• $250.84 charger + LVC ... Batteries 8 x $50 = $400 ... total $650US.

Purchased batteries, charge, and guages

• 9 x T5000.5S.20 - Turnigy 5000mAh 5S 20C Lipo Pack $449.91 (6867g)
• 1 x iCharger1010B - iCharger 1010B+ 300W 10s Balance/Charger $190.00 (749g)
• 2 x BM-6 - BM-6 Cell Voltage Monitor 2-6S Lipo $25.90 (58g)
• 1 x Cellmeter-8 - Cellmeter 8 for Lithium Polymer Packs $97.95 (165g)

All coming from hobbyking.com, paid with PayPal.

And that's enough for today !

Steps still required

1. Work on mounting the compressor on the tank.
2. Begin creating circuitry for electronic vacuum switch (to turn compressor on/off)

14/07/09 Achievements

These are the things I did today:

• Discovered the "true" danger of LiPo batteries (fire etc).
• Researched LiPo charging (not "set and leave")
• Found the "perfect" BMS for LifPO4 batteries
• Went to Enzed (pressure fittings) and got the parts for vacuum machinery
• Hooked up the vacuum with the tank, and got it working (hooray)
• Researched battery charging.

Steps still required:

1. Check SLA weights (possible ?)
2. Check power supplies (economical ?)
3. What will be the delay with Headway cells ? (email Victoria at Headway)
4. Check Thundersky weights (alterntive ?)
5. Complete list of the two system costing (LiPo -vs- Headway)
6. Complete list of benefits / disadvantages of both systems

14/07/09 Pics - billycart

The photo above is of the Plug, made of Cedar strips over MDF formers, before the sanding got too serious.

Smoothed plug.

So far, this has 3 coats of Primer, and has been sanded down.

I am not really happy with it yet. It is as smooth as a car ... but if you look really, really carefully, you can see the smallest of tiny little waves in the finish.

I would like to get these out.

15/07/09 Pics

A picture of the old compressor tank that Poppy picked up from the dump for $10.00.

I bought fittings for it (BSP threads) to connect to the compressor that I've got, then ran it down to around 25inches of mercury. It holds vacuum beautifully. By that, I mean that it didn't collapse with an enormous crash.

Next step - is to mount the compressor motor, electronic vacuum switch, and tap.