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