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#81
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glider battery duration problems
GC wrote, On 10/23/2013 2:18 AM:
On 8/10/2013 04:17, son_of_flubber wrote: The internal "completely discharged" capacity of a Shorai LFX is 1/3 the rated "PBeq" capacity. For example, the LFX18 12V series have 6Ah cells internally. But the cells are capable of 80% discharge without damage and while retaining more cranking ability. As such, the USABLE capacity(or "reserve capacity") of an LFX18 12V battery is on or very near par with 18AHr-rated lead acid batteries, while providing superior cranking performance and a vast reduction in weight. The Shorai PBeq AHr (lead-acid equivalent) rating system therefore allows users to compare a very different technology from lead-acid, but on a close apples-to-apples basis when making a choice. So they say. In the famous words of Miss Mandy Rice-Davies "They would say that wouldn't they". BTW - how big is "vast"? According to Shorai, it's about a 5:1 weight reduction. That's also a clue to why they aren't good for energy storage: there just isn't enough material inside the case to store the energy you expect for the "[equivalent] amp hour rating". A typical Li-Fe battery will weigh about half of what an SLA weighs for a given amp hour capacity. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) |
#82
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glider battery duration problems
On Wednesday, October 23, 2013 5:18:15 AM UTC-4, GC wrote:
On 8/10/2013 04:17, son_of_flubber wrote: The internal "completely discharged" capacity of a Shorai LFX is 1/3 the rated "PBeq" capacity. For example, the LFX18 12V series have 6Ah cells internally. But the cells are capable of 80% discharge without damage and while retaining more cranking ability. As such, the USABLE capacity(or "reserve capacity") of an LFX18 12V battery is on or very near par with 18AHr-rated lead acid batteries, while providing superior cranking performance and a vast reduction in weight. The Shorai PBeq AHr (lead-acid equivalent) rating system therefore allows users to compare a very different technology from lead-acid, but on a close apples-to-apples basis when making a choice. So they say. In the famous words of Miss Mandy Rice-Davies "They would say that wouldn't they". GC Shori confirmed by email that they only make batteries for "starting applications". We knew that but it is good that they admit it. The marketing people always lie and for that reason I do not judge a battery by its website. Maybe we will see some new products come up for Spring. |
#83
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glider battery duration problems
On Wednesday, October 2, 2013 11:46:32 AM UTC-6, John Marshall wrote:
I need advice about the best choice of batteries for an asg 29e. lithium ion would be outside manufacturer's remit and the insurer's plus too many risks-the fuel tank is directly above the battery housings. I would like something with at least 9 amp hours, whether gel cell or mh. Maybe this is way off track - but maybe you have a transponder ? if most transponders are not specially programmed (set up) they will run all the time - they are "on" all of the time - drawing power even when your panel read out says "off" - I had that problem in 2 gliders - EB28 Edition - another solution to check this power loss is to unplug the transponder and see if that solves the problem - if it does then get out your manual and find out how to change the settings - good luck |
#84
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glider battery duration problems
On Wednesday, October 2, 2013 11:46:32 AM UTC-6, John Marshall wrote:
I need advice about the best choice of batteries for an asg 29e. lithium ion would be outside manufacturer's remit and the insurer's plus too many risks-the fuel tank is directly above the battery housings. I would like something with at least 9 amp hours, whether gel cell or mh. from another posting - I did, however, get behind my panel last week and changed out my master switch for one more substantial in current capability and have experienced a major improvement in function of my equipment. The switch that was installed when I bought the glider was adequate for the CAI302 and the MicroAir 760 but, after installing a Trig transponder, a Dell Steak and a Zaon MRX, all operated from the same bus, the current capacity of the master switch was the limiting factor. After two flights with the new master switch installed it would appear that the problem is solved. |
#85
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glider battery duration problems
On Wednesday, October 23, 2013 8:15:26 PM UTC-4, wrote:
if most transponders are not specially programmed (set up) they will run all the time - they are "on" all of the time - drawing power even when your panel read out says "off" Say what ? A transponder should draw very little power except when it is transmitting, which it only does when interrogated. A Mode S transponder draws less than Mode C as it responds to selective (fewer) interrogations (yes Daryll, I'm simplifying). The only notable draw for a transponder installation would be a poor quality encoder (older models have power-hungry heaters rather than temperature-compensated altitude transducers); should not be a problem for modern units... Perhaps you can email me offline make/model of the setup which gave you power problems? Hope that helps, Best Regards, Dave |
#86
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glider battery duration problems
When I turn my master switch off, power is removed from the DC bus. My
transponder is powered from the bus. Switch off = no power drain. wrote in message ... On Wednesday, October 2, 2013 11:46:32 AM UTC-6, John Marshall wrote: I need advice about the best choice of batteries for an asg 29e. lithium ion would be outside manufacturer's remit and the insurer's plus too many risks-the fuel tank is directly above the battery housings. I would like something with at least 9 amp hours, whether gel cell or mh. Maybe this is way off track - but maybe you have a transponder ? if most transponders are not specially programmed (set up) they will run all the time - they are "on" all of the time - drawing power even when your panel read out says "off" - I had that problem in 2 gliders - EB28 Edition - another solution to check this power loss is to unplug the transponder and see if that solves the problem - if it does then get out your manual and find out how to change the settings - good luck |
#87
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glider battery duration problems
Mode C Transponders I've used have a heater in the separate altitude encoder. This is a factor whenever the unit is turned on.
Jim |
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