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It has arrived......Portable Charging Station
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<blockquote data-quote="Virtual1" data-source="post: 22258" data-attributes="member: 4084"><p>FWIW I went looking for an economical but effective larger scale battery charge system, and here's what I came up with: <a href="https://www.amazon.com/gp/product/B075K37YT5" target="_blank">https://www.amazon.com/gp/product/B075K37YT5</a></p><p>(they got taken apart for modification, and I found they were designed much better than I was anticipating, they're microprocessor-controlled and adequately rated, though they could use better cooling)</p><p></p><p>I bought three of these, $18 ea. So for $54 I can charge six Spark batteries at a time. (plus a controller and phone/tablet) They run off 12v, so I hardwired them to a single 12v harness (powerpole connector actually) to an 18AH SLA battery. You can get the 7AH SLA's all over the place and charge them with any cheap low powered battery charger or maintainer, but an 18 will hold a lot more power - those are often referred to as "fire alarm batteries" and can be found where commercial fire products are sold such as fire extinguishers. (or just lug a car battery, cheap from the local auto salvage) Take that out to the park and you can charge lots of batteries. How much you can recharge is only limited by the size of the 12V battery you bring. (car battery or in-car = a lot more) Spark rates their batteries at under 17WH. If we want to guess 85% efficiency, an 18AH battery (@12v) contains 216 WH (12*18), 85% of that is 183WH, so we can top off <em>at least</em> 10 (completely dead) 17WH Spark batteries using that. Since we don't run them flat usually, forget the 85% and we can just call it an even dozen charges?</p><p></p><p>I'm expecting this "single conversion" method to be significantly more efficient than inverting 12 up to 120 and then back down using say the flymore charging sled. (each conversion wastes some power) It also costs a lot less if all bought separately - $10 less for the charger, save $15-20 more not having to buy a small inverter, all while charging twice as many batteries at a time. I'm guessing a typical car battery (~500WH) would charge around 30 Spark batteries. (or essentially unlimited in a periodically-running vehicle)</p><p></p><p>Does anyone spot any errors in my math, or see any grossly bad or wild assumptions?</p></blockquote><p></p>
[QUOTE="Virtual1, post: 22258, member: 4084"] FWIW I went looking for an economical but effective larger scale battery charge system, and here's what I came up with: [URL]https://www.amazon.com/gp/product/B075K37YT5[/URL] (they got taken apart for modification, and I found they were designed much better than I was anticipating, they're microprocessor-controlled and adequately rated, though they could use better cooling) I bought three of these, $18 ea. So for $54 I can charge six Spark batteries at a time. (plus a controller and phone/tablet) They run off 12v, so I hardwired them to a single 12v harness (powerpole connector actually) to an 18AH SLA battery. You can get the 7AH SLA's all over the place and charge them with any cheap low powered battery charger or maintainer, but an 18 will hold a lot more power - those are often referred to as "fire alarm batteries" and can be found where commercial fire products are sold such as fire extinguishers. (or just lug a car battery, cheap from the local auto salvage) Take that out to the park and you can charge lots of batteries. How much you can recharge is only limited by the size of the 12V battery you bring. (car battery or in-car = a lot more) Spark rates their batteries at under 17WH. If we want to guess 85% efficiency, an 18AH battery (@12v) contains 216 WH (12*18), 85% of that is 183WH, so we can top off [I]at least[/I] 10 (completely dead) 17WH Spark batteries using that. Since we don't run them flat usually, forget the 85% and we can just call it an even dozen charges? I'm expecting this "single conversion" method to be significantly more efficient than inverting 12 up to 120 and then back down using say the flymore charging sled. (each conversion wastes some power) It also costs a lot less if all bought separately - $10 less for the charger, save $15-20 more not having to buy a small inverter, all while charging twice as many batteries at a time. I'm guessing a typical car battery (~500WH) would charge around 30 Spark batteries. (or essentially unlimited in a periodically-running vehicle) Does anyone spot any errors in my math, or see any grossly bad or wild assumptions? [/QUOTE]
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It has arrived......Portable Charging Station