Taperssection.com
Gear / Technical Help => Remote Power => Topic started by: H₂O on January 08, 2013, 09:22:54 PM
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http://www.shoraipower.com/Products/batteries/ (http://www.shoraipower.com/Products/batteries/)
Anybody ever use these LiFePO4 (https://www.batteryspace.com/lifepo4cellspacks.aspx) batteries?
They are drop in replacements for SLA motorcycle batteries and can be charged of most (non-trickle style) SLA chargers - alternatively you can buy their Lithium charge for more functions.
They come in alot of sizes and are very light.
Specs PDF:
https://system.netsuite.com/core/media/media.nl?id=230&c=3379047&h=eded4c1874bc24e92e3f&_xt=.pdf&ck=GLoy6lK-AWIsGrCf&vid=GLoy6lK-AWYsGn5p&cktime=114258&gc=clear (https://system.netsuite.com/core/media/media.nl?id=230&c=3379047&h=eded4c1874bc24e92e3f&_xt=.pdf&ck=GLoy6lK-AWIsGrCf&vid=GLoy6lK-AWYsGn5p&cktime=114258&gc=clear)
The Wh versus Ah seems off - i.e. a 21Ah 12V battery is only rated at 93 Wh which to me doesn't match up - typically Wh = Ah x Voltage - so the Wh should be more like 240 not 93
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Per there FAQ (Sounds like you need to go off the Wh rating which is much lower then the Ah rating they are advertising - not as good of a deal as I expected):
Q. How does the LFX "PBeq AHr" capacity rating compare to lead-acid Ahr ratings?
A. First, we need to understand that the primary job of a starter battery is to flow a large current (amperage) for a short time, in order to start a vehicle. In order to do that efficiently, the battery must have low internal resistance. Holding all other considerations equal, the larger the battery is in capacity the lower the resistance, and the better able it is to crank a vehicle under high loads.
Lead-acid makers have therefore used AHr(capacity) ratings as shorthand to indicate cranking ability, rather than a real usable capacity. The lead-acid capacity rating itself is based on a complete discharge at a low discharge rate. Under actual cranking conditions they will deliver considerably less than spec capacity. And because lead-acid batteries begin sulfating when only a small percentage of the capacity has been used, and their internal resistance rises as they are discharged, the actual capacity which can be USED may be as little as 20% of the mfg. rating. Discharge in excess will not only damage the lead-acid battery, it may not allow proper starting as voltage sags.
Shorai LFX are based on a completely different chemistry. Not only do they have less than 1/3 the internal resistance per capacity than do lead-acid, they are also the ultimate "deep-cycle" battery. 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.
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I will say after looking around the interweb over the last few days there is alot of new products out there.
Alot of SLA drop in replacement batteries that are typically about 50% lighter and offer about 30+% capacity increases while able to use the existing SLA chargers
It looks like alot of companies are investing alot into getting LiPoly batteries into vehicles and do it cheaply - which means alot of money is going into the technology and this can only benefit us.