tag:blogger.com,1999:blog-1592992209402300549.post1295719383663833148..comments2024-03-29T07:33:41.566-04:00Comments on The Silicon Graybeard: Can't Live With 'Em ... SiGraybeardhttp://www.blogger.com/profile/00280583031339062059noreply@blogger.comBlogger12125tag:blogger.com,1999:blog-1592992209402300549.post-34293675889435597922020-07-19T13:26:38.367-04:002020-07-19T13:26:38.367-04:00I doesn't look like that's how it could be...I doesn't look like that's how it could be. <br /><br />That plot in the post shows what looks to be an unregulated output that's labeled 12V 10A. It's pretty much the same as what 3 unregulated Li-Ion cells in series would do. If it's a single 3.7V cell with a power circuit, that's one strange little voltage regulator. <br /><br />There are other outputs on the box, both USB format. USB regulators are cheap, and I expect them to be better regulated than the 12V output. <br /><br />If the listing had said that everything is limited to 66.6 AH, I'm not sure I would have bought it. <br /><br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-75958315203528340292020-07-19T12:09:54.019-04:002020-07-19T12:09:54.019-04:00You got what was specified...
The CELL is 18AH bu...You got what was specified...<br /><br />The CELL is 18AH but the votlages is 3.7V nominal or about 66WH.<br />I hear everyone going wut? Its not a 12V battery in there its a single LiPo or LiFepo and a pover converter to deliver a peak current for maybe 10 seconds of maybe 800A. Use Watts/time and 66Wh for one minute can easily be 3900watt/minute. Ohms law and resistance will limit that greatly.<br /><br />So your testing says 66wh for 5 hour rate is likely correct.<br /><br />FYI for those that insist it was a 3S pack of 1AH cells if it were <br />then that would be a 205WH battery or 18AH times 11.4V nominal.<br /><br />Eck!Eck!https://www.blogger.com/profile/13890237094647111653noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-29606946797022901992020-07-19T10:45:42.740-04:002020-07-19T10:45:42.740-04:00I'm not 100% sure I get the question, but if y...I'm not 100% sure I get the question, but if you're asking if it's reasonable I have three 3.7V 18 AH batteries in series to make the 11.1V output, no. That's not what I measure.<br /><br />When batteries are added in series, the current doesn't add, just the voltage. I cut the test at about 3.6 AH when it seemed close to the rapid voltage drop at the end of capacity. What I seem to have is three 3.7V 3.5 to 4 AH batteries in series. <br /><br />To add currents, the batteries would have to be in parallel connections of three battery series strings. For the sake of illustration, if the batteries were 3.6 AH (just a bit less than I measured), there would need to be five parallel strings of three batteries in series. 15 cells. But if that was what was inside the box, I would have measured close to 18 AH, not 3.6. <br /><br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-69602936696009260612020-07-18T15:30:07.492-04:002020-07-18T15:30:07.492-04:00Does 18 AH @ 3.7 Volts seem about right?Does 18 AH @ 3.7 Volts seem about right?AuricTech Shipyardshttps://www.blogger.com/profile/03927256827579418519noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-71476370214284946922020-07-17T21:34:48.857-04:002020-07-17T21:34:48.857-04:00Yes, when I first put it on the battery analyzer, ...Yes, when I first put it on the battery analyzer, it "suggests" the battery is 11.1V and three cells. Whether the reason for calling it 18AH is as you suggest is speculative, but all I <b>know</b> is what I measure and it's certainly not 18 AH. It might well be 6AH. <br /><br /><i>I thought you were some sort of radio engineer?</i> I got a laugh out of this. The sort of radio engineer I am now is "retired." Before that, the sort was "career long". Radio Frequency engineer does not overlap with battery engineer. I worked on exactly one radio that was to be battery powered, back around 1990. The company I call Major Southeast Defense Contractor had a power supply engineer design that. <br /><br />All I know about lithium batteries has been hobby-associated reading and experimenting. <br /><br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-61349210826226258192020-07-17T21:10:44.160-04:002020-07-17T21:10:44.160-04:00The marketing math here is straightforward and dec...The marketing math here is straightforward and deceptive. Agree with your hunch that the manual's 66.6 Wh rating is truthful. We might equivalently describe the battery pack as 6 Ah at 11.1 V. Note 6 Ah times 11.1 V equals 66.6 Wh.<br /><br />Next, drjim has postulated the battery pack is composed of lithium polymer cells in a 3S configuration. I agree. Three cells in series. LiPo cells generally are described as having nominal voltage of 3.7 V each. 3 times 3.7 V equals 11.1 V. <br /><br />Next recall the capacity of the battery pack is 6 Ah. Cells of the pack are connected in series. So each of the three cells could be labeled as 6 Ah, assuming 3.7 V per cell.<br /><br />Methinks some marketing dumbass unfamiliar with series and parallel arithmetic saw three cells inside the battery pack, each labeled as 6 Ah. Said dumbass computed 6 times 3 equals 18 and plastered an "18 Ah" rating on the package. Discrepancy solved.<br /><br />I thought you were some sort of radio engineer?Just a Medicnoreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-88025033182040886522020-07-17T07:49:48.708-04:002020-07-17T07:49:48.708-04:00Thanks DrJim, that's the best summary of read ...Thanks DrJim, that's the best summary of read of these things anywhere! <br /><br />The cables are marked 8 AWG, but the copper isn't actually visible. The cable could be molded cheese for all I know. It uses a large connector, like my others have, which means it's not that out of line with others. When my alternator died back last winter, I used the predecessor charger several times, but my engine is 4 Liter V6 and I'm sure it doesn't take 800 CCA. <br /><br />While searching the Amazon page, I ran into something that's a red flag "if I knew then what I know now". It says the pack can be recharged from dead to full in 4.5 hours. Now that I have one I know the charger is a 15V, 1A wall wart. Now how does 4.5 hours delivering 1 amp turn into 18 AH? Even if you give every possible benefit of doubt, and say that's 15 Watts, in 4.5 hours you have 67.5 WH, which is the closest to the spec of 66.6 that I've seen. <br /><br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-76852546304739700772020-07-17T07:23:15.070-04:002020-07-17T07:23:15.070-04:00If I could just remember to turn my headlamps off....If I could just remember to turn my headlamps off....Ed Bonderenkahttps://www.blogger.com/profile/03724552853113809036noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-84320027342640330072020-07-16T23:02:33.527-04:002020-07-16T23:02:33.527-04:00You have what's called a "3S" pack i...You have what's called a "3S" pack in the R/C world, something I've learned a LOT about in the last year since I picked up the R/C hobby again.<br /><br />The cells are made by the zillion, poorly graded, slapped into packs, and sold cheap because they are cheap. The come in a wide range of sizes and ratings, and the guys who are seriously into R/C have made an extremely thorough study of them.<br /><br />Your measurement technique is acceptable. There's no "magic" about a LiPo, and if it's rated 10Ahr, it should be able to meet that spec.<br /><br />90% of them fail miserably at meeting their published specs. Some of it definitely reminds me of the "Output Power Wars" stereo equipment went through, but a large part is just fraud. They KNOW nobody's going to test them but a few geeks like us, so....they lie.<br /><br />What size wire leads are on the pack? What connectors are they using? Unless they're 8/10ga, there's no way you can pull "800 Cold Cranking Amps" out of it.<br /><br />I've had numerous friends who got burned on those little jump-starters, although some of the newer ones with LiPo's are supposed to be quite good.drjimhttps://www.blogger.com/profile/05647484115197408897noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-40564989355565249202020-07-16T21:57:44.073-04:002020-07-16T21:57:44.073-04:00The coincidence is that is the update to the one I...The coincidence is that is the update to the one I dropped and broke. I know GooLoo, and actually jump started my car when the alternator died a few months ago. <br /><br />The one I had is obsolete now, but same basic package, five blue LEDs and everything, except it was rated 15 AH instead of 18. <br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-91394483499772752542020-07-16T21:54:05.006-04:002020-07-16T21:54:05.006-04:00When I got a trailer and started into RVing, I cam...When I got a trailer and started into RVing, I came across this book: RV Electrical Systems by Bill Moeller. I learned more about 12v systems from him than my previous fifty years experience with auto mechanics, not least of which is theory and practice of multi-stage charging.<br /> I was reading it on one of our first winter camping trips, and my wife was watching one of the early episodes of Breaking Bad, where Walt and Jesse are stranded with the RV's house and starting batteries dead. They pull out a generator to recharge and it catches fire. I told her that was EXACTLY why I was reading that book!<br />Greghttps://www.blogger.com/profile/06183459827508486809noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-19025003161442383722020-07-16T21:47:21.166-04:002020-07-16T21:47:21.166-04:00Do you use this for emergency starting? If it’s f...Do you use this for emergency starting? If it’s for ‘other’ uses, ok, but there are miracle car starters out there now; a complete bafflement to this old guy. <br />My son gave me a gizmo that will start my old 350 v8 dump truck, as well as my diesel tractor (used on both). Check ‘em out... mine is this one:<br /><br />https://www.amazon.com/GOOLOO-18000mAh-SuperSafe-Starter-Portable/dp/B0748D8KT6/ref=sr_1_1_sspa?crid=3KFHATBI1IP9O&dchild=1&keywords=gooloo+jump+starter&qid=1594950066&sprefix=Gool%2Caps%2C375&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFHWDRSTk5UNFlRMTkmZW5jcnlwdGVkSWQ9QTAwMTA1NzhRV1JUR1VER0laSVEmZW5jcnlwdGVkQWRJZD1BMDc5MDY5NTFUU0tXTllZMEZHRDgmd2lkZ2V0TmFtZT1zcF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl<br />Then, you can recharge the unit from the now running vehicle.<br />Amazing gadgets that work!<br />doubletroublehttps://www.blogger.com/profile/04378163493817522427noreply@blogger.com