Hi Luke, hello Scott Thank you both for your input. It is valuable and very much appreciated - just keep it coming!!! This highly relevant information is useful for most (if not all) glider pilots on this list. Kind regards to all! Bernard
_____ From: [email protected] [mailto:[email protected]] On Behalf Of Luke Dodd Sent: Thursday, 28 February 2013 4:14 AM To: Michael Scutter; Discussion of issues relating to Soaring in Australia. Subject: Re: [Aus-soaring] LiFePo4 I have been trialling the shorai and can support Johns assessement . Shorai rate their capacities on a cold cranking equivalent, its is entirely misleading if you are looking for a battery to supply a steady current over a long period of time. Their 14 ah will not supply 14ah for 1 hour or 1 ah for 14 hours. I have used their 7ah rated cells and its equivalent capacity compared to SLA or Nimh is more like that of a 2 ah cell. Also they are destroyed by deep discharge. Luke dodd From: Michael Scutter <mailto:[email protected]> Sent: Tuesday, February 26, 2013 3:55 AM To: Discussion of issues relating <mailto:[email protected]> to Soaring in Australia. Subject: Re: [Aus-soaring] LiFePo4 John, that is really interesting. Have you sampled more than one battery or repeated the test on the same battery? Michael Scutter, Education & Training Consultant, Email: [email protected] Mobile: 0417822330 (Int +614178223300) skype://michaelscutter I don't say anything here that I would not say to your face. _____ From: John Parncutt <[email protected]> To: 'Discussion of issues relating to Soaring in Australia.' <[email protected]> Sent: Tuesday, 26 February 2013 5:57 PM Subject: Re: [Aus-soaring] LiFePo4 Hi David, The link you provide is to exactly the same model of Shorai battery I have been evaluating. The load tests I have done give it an actual capacity of 4 A/H (far from the stated capacity of 14 A/H). I have attached an image of the results for your info, for comparison the results on one of our clubs existing (used) lead acid glider batteries is also included. This clearly demonstrates the ability of the Lithium battery to provide an almost constant voltage across its complete discharge period whereas the lead acid battery voltage continually drops to a point where some of our instrumentation and particularly the radio in transmit mode may fail about halfway through discharge. If you note the Shorai literature states an equivalent A/H rating to that of a 14 A/H lead acid battery not an actual A/H rating. This is misleading and I think a bit of sales spin! The comparison I think is based on the Cold Cranking capacity of the battery, ie. the ability to delivery large currents to a starter motor bearing in mind these batteries are designed to replace wet lead acid motorcycle batteries. The bottom line is that the 14 A/H Shorai battery will not deliver 1 amp continuously for 14 hours, well certainly not the one I tested!! John Parncutt From: [email protected] [mailto:[email protected]] On Behalf Of David Conway Sent: Tuesday, 26 February 2013 4:38 PM To: 'Discussion of issues relating to Soaring in Australia.' Subject: Re: [Aus-soaring] LiFePo4 Agreed; something like this would be better http://www.shoraipower.com/s.nl/it.A/id.91/.f 14AH - twice that of a normal SLA glider battery - and less than half the weight @ 662g David From: [email protected] [mailto:[email protected]] On Behalf Of Future Aviation Sent: 26 February 2013 15:02 To: 'Discussion of issues relating to Soaring in Australia.' Subject: Re: [Aus-soaring] LiFePo4 Hi Ian >From a safety point of view this is much better than what the Boeing dreamliner is using. However, I would never put a battery like that in a glider unless it is securely placed in a much more impact resistant enclosure. Kind regards Bernard _____ From: [email protected] [mailto:[email protected]] On Behalf Of Ian Mc Phee Sent: Tuesday, 26 February 2013 2:15 PM To: Discussion of issues relating to Soaring in Australia. Subject: [Aus-soaring] LiFePo4 About $87 and notice a new Arcus M was fitted at factory with something similar. This is NOT what B787 is using. Ian M http://www.hobbyking.com/hobbyking/store/__22656__ZIPPY_Flightmax_8400mAh_4S 2P_30C_LiFePo4_Pack_AUS_Warehouse_.html _______________________________________________ Aus-soaring mailing list [email protected] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring _____ _______________________________________________ Aus-soaring mailing list [email protected] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring
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