john stones 1 - Moderator Posted April 3, 2017 Share Posted April 3, 2017 Anyone using these, opinions please. John Quote Link to comment Share on other sites More sharing options...
Andy48 Posted April 3, 2017 Share Posted April 3, 2017 I bought a few last year when they were on a very good offer. They were 40C. (I notice my low C batteries always fail before the higher C ones, for fairly obvious reasons.) They are very nice, with a lower IR than the batteries they replaced. Seem to work very well. I'd give the 10C ones a miss though. Will tell you my final thoughts hopefully in a few years.... Quote Link to comment Share on other sites More sharing options...
Pete B Posted April 3, 2017 Share Posted April 3, 2017 10C ones are utterly hopeless, IMHO.... LV warning within a couple of minutes of take-off..... Pete Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted April 3, 2017 Author Share Posted April 3, 2017 I have 65c ones for my quad. Quote Link to comment Share on other sites More sharing options...
Andy48 Posted April 3, 2017 Share Posted April 3, 2017 I should add I'm using mine in small planes and a small heli. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted April 3, 2017 Share Posted April 3, 2017 HK had some Multistar 6000mAh 4s 2c (two C!) on a ridiculously low offer last year. That meant they should have been capable of 12A for 30 minutes but they struggled to deliver 2A for that time so nowhere near 6000mAh capacity.. Maybe that is why they were so cheap! . Quote Link to comment Share on other sites More sharing options...
Dave Bran Posted April 4, 2017 Share Posted April 4, 2017 Warning, engaging tongue in cheek mode. Odd behaviour here, and I'm thinking not just solely from the cell packs. Firstly, surely by now everyone knows and accepts that across the whole spectrum seller stated discharge "C" ratings are usually an extremely rough guide, are often overblown, and sometimes drastically so? (not specifically relating to links and types stated here, your mileage may vary ) Does everyone not calculate AND THEN MEASURE IN USE what their current draw is and then choose AND ADJUST pack type accordingly? Before Telemetry I used to use an on board recorder to do this, now telemetry makes this much simpler. Sorry, but I have read this thread with increasing concern at the lack of real data being stated, and finally freaked at the generic statement that Low C packs fail before high C packs "for obvious reasons"? WHAT obvious reasons? Only if the actual use does not fit the packs capability and design spec!! Example, a camera type multicopter has a VERY different load demand even over a "race" or freestyle type quad, let alone that for a helicopter, be it governed or not. As for fixed wing, the variability in current demand across a packs discharge is even more extreme. Low "C" discharge high capacity packs for their size and weight were introduced and originally intended for slow moving camera drones where duration is all and current demand hardly varies over the whole flight time. They were designed to give up the ability to provide variable discharge with intermittent large service peaks to provide the maximum extended near level discharge times before voltage sag. As such they do not have lower internal resistance when comparing discharge C ratings to the more usual fare, hence a reason why their discharge rating is lower. If you are not correctly choosing the pack ratings to match the ACTUAL use while allowing for many manufacturers "ambitious" figures, then expect poor results. As to buying when packs are on super special offers. I don't go there. You may consider it a great deal, I just visualise an overstocked bin with the "sell by" date fast ticking away or expired I could (but won't!) point at a couple of UK sellers that currently have stock on sale of a cell manufacturer/type that ceased to be made more than four years ago, so they must have been sat in storage mode (presumably!!) at least that time. Nothing tells you this if you do not know and do not seek to investigate. Workman, tools, bad, blames, a, his.................rearrange..........................Let the buyer beware, and let them have done their homework first!! [disengage TIC mode] Quote Link to comment Share on other sites More sharing options...
Andy48 Posted April 4, 2017 Share Posted April 4, 2017 Posted by Dave Bran on 04/04/2017 07:37:56: Does everyone not calculate AND THEN MEASURE IN USE what their current draw is and then choose AND ADJUST pack type accordingly? Before Telemetry I used to use an on board recorder to do this, now telemetry makes this much simpler. Sorry, but I have read this thread with increasing concern at the lack of real data being stated, and finally freaked at the generic statement that Low C packs fail before high C packs "for obvious reasons"? WHAT obvious reasons? Only if the actual use does not fit the packs capability and design spec!! Yes I do measure the current draw very carefully, and for my application 20C were more than adequately specified, AND I have full on-board telemetry of both individual cell voltage and current drawn. However, flying the same plane with a mix of 20C and 40C packs of the same make, the 20C ones failed long before the 40C. I would have thought the reason WAS obvious. 40C packs are heavier and slightly larger than their 20C counterparts and capable of handling a far higher current, so at the application level they were being used (ie at a max of 12C) they were being stressed far less, and has been pointed out already, any C rating should be taken with a very liberal pinch of salt. At the risk of boring everyone else to death, I could go into much further detail, and provide a whole raft of telemetry data. ..... Quote Link to comment Share on other sites More sharing options...
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