Keith Miles 2

I agree with Trevor and Robin. The problem is either volt drop in the leads, which would be my first instinct or a signal issue which I would have thought less likely given that this is not an unusual set up. And as Trevor says, don’t let the thickness of the insulation fool you. You certainly wouldn’t be the first, or are likely to be the last to make that error. It’s one thing that annoys me that cable size is rarely quoted, at least in my experience. All that one tends to see is “Heavy Duty” and even that can be a leap of faith unless buying the truly “genuine” article at a premium price! As suggested, start by trying everything outside of the model, with leads and servos laid out straight and kept well apart. If it’s volt drop, as I suspect, the problem will still be there.

Ah, yes, Digimite. Not to everyone’s taste. You either love it or hate it.

First off, I’ve only ever used, with one recent exception, 4-cell NiCd or NiMh received wisdom having been that higher voltage can upset servos as seems to have been confirmed in this thread. I have never had cause to test my present collection on 5-cell nor, until very recently, any reason not to to stick with 4.8v (nominal, of course!). Martin, I’ve never had the need over the years, in my models, to use anything larger than 1500mah and more recently, it seemed that 1000mah were sufficient for my purposes and, as said, and whilst perhaps not a significant factor in practice, the lower capacity for a given physical size will, nevertheless, have comparatively lower internal resistance and should be less susceptible to volt drop at a given load. My current (!) concerns are unrelated to capacity, which has been proved to be perfectly adequate, but an apparent premature deterioration in the point at which a volt drop occurs at 0.5C ((500mA). I don’t own any digital servos either or a re-think would certainly be needed! Pete, I certainly echo the dubious longevity and inconsistencies with Lipos. I have certainly had this experience with my indoor models with all E-Flite, of various sizes, being not only the most expensive but the least durable! Flying field chat also tends to suggest a lack of consistency even, occasionally, between supposedly identical packs! Nigel, Yes, saw the 2000 NiMhs on Component Shop as well as a few other sites. As for the “Lites”, I only bought these because they seemed to predominate and weren’t as I recall, specifically identified as such nor did I have cause to search for anything more specialised. By the way, what does “YMMV” mean?

Some more useful posts, there, much of which gels with my own thoughts and echoes my frustrations! Another “niggle”, for me at least, is finding alternative chemistries with the correct connector without having to buy or make up adaptors plus, of course having to make possible constructional adjustments to the model as well. And, yes, I totally agree that the safety recommendations for Lipos, removal for charging for example, does not make them the most convenient choice for Rx packs especially given the general advice (but sometimes conflicting!) about storage charging! I do take on board that LiFe, if it becomes necessary to change chemistry, seems to be, on balance (no pun intended) the more practical option, assuming that my 6v servos and receivers will tolerate the 10% over-voltage. It does seem that a few 1000 and 2000 NiMh packs are still on some shelves, even if no longer made, but the worry might be about how long they’ve been sitting there! As for 6v regulators, that seems to me to be an Etronix monopoly and stockists also seem somewhat limited and, yes, it does possibly add another element that might fail! Is it my rose-tinted glasses leading me to the view that things were once much more simple?

Well after all the preceding discussion, I have just discovered that Overlander no longer do any of the packs that I currently have! My choice, of suitable capacity, from Overlander at least, is now either 6v/2300 flat, 4.8v 2300 flat or 4.8v 2300 square. Am I the only one who feels, that as one gets older, obsolescence seems to accelerate as does expenditure? Grrrrrr! I’m 67 and there is no way, in my remaining lifetime, that I will willingly replace all of my servos and receivers or, for that matter, convert my IC models to electric for two reasons, my mortality and my wallet! So, it seems to be either “revival” of my NiMh packs or Lithium and maybe a regulator! The latter is looking like the front runner! Interesting discussion, though!

Always fascinating to read conflicting opinions. I have had the same experience when reading those of apparent professionals which doesn’t help to remove confusion! in view of my most recent discovery, and I suppose that it’s something that I have subliminally known all along, there is probably no such thing as a totally reliable battery that needs no monitoring, especially in applications where failure might be disastrous. All batteries have a limited working life, whatever the chemistry, so it’s probably a good idea to have a reliable means of monitoring any Rx packs for their natural deterioration in order to know when to replace them before they fail in use. Doing so, I would suggest, might have prevented a lot of crashes and might help to prevent future ones! I sense that even telemetry, whilst very useful, might not be an entirely reliable source of comfort or ideal safety net and I would not be surprised if models have crashed due to a weakened battery even where telemetry was fitted. Just my own thoughts. Oh, there goes the beeper! Forming Charge completed on the best of my packs. At least it will give me something to compare the rest with when I’ve got some more figures! I would rather resuscitate before, perhaps, buying direct replacements or, perhaps, changing my past habits for a new regime!

Pete, Rest assured all comments are noted. Currently (pardon the pun) I’m up for everything! Bear in mind, mine are 1000mah packs not 2000mah, so my 0.1C is 100ma not 200ma and discharge current would, similarly, be 0.5A not 1A. I’m on the same page as you, though! Duff cell report pending! It might take a while, unless I report one at a time. Some might be bored with this thread already and some might enjoy being kept in suspense!

Pete, On the “white case” issue, I only recently discovered, during my research into my current problems, that there have been, apparently, two incarnations of Eneloop. As stated in my original post, the first were apparently good for 500 cycles, the second for 2100 cycles, hence the apparent original colour coding. I’ve also just noted, however, that my Overlander Blue cells are Panasonic and the White ones are Sanyo! Make of that what we will! Happy to read your comments in support of NiMh, for obvious reasons!     Couple of further points that come to mind. Firstly, in terms of discharging to 1v/cell, nobody has yet observed that the end voltage is dependant on the discharge current applied which is why the voltage goes back up again when the discharge stops/current load is removed. To get a true 1v (flat) at the currents quoted would require driving the voltage below 1v (not a good idea, especially at high current) during the discharge. So, if I want to obtain a truer 1v, I start with a higher current and gradually reduce it in stages. Sorry to be pedantic! The second point concerns Rx/Radio battery testing in general and not necessarily NiMh. Seems to me that probably the most reliable way to test batteries once the performance parameters required have been decided upon, is to perform a load test/discharge on the fully charged battery when new, at a given current load and to a desired level of voltage drop/capacity reduction, noting the figures obtained, and then occasionally thereafter, in similar fashion, comparing the performance over time with the original figures obtained. In view of most recent experience where a crash might seem to have been imminent, despite my normal assumed “safe” procedures, that is what I intend to do from now on. Telemetry, of course (more expense!) is an alternative or an added bonus in many circumstances. Seems it’s never to late to learn. I certainly have and the process continues as do my battery investigations! Oh, and as I type this, that Forming Charge has just completed after only 2 hours and 40 minutes with just 324mah of Charge at 6v cut-off!  Methinks it’s on the way to my local recycling centre! At least it won’t be taking my PT19 with it!   Edited By Keith Miles 2 on 13/08/2020 18:28:24

Thanks, Brian, Barrie, Jesus And Bob! All good stuff, guys. Much food for thought for one who is still catching up! One concession recently made, in view of the weight of the model and the additional number of servos, was to fit a 7.4 v 1000mah Lipo And 6v regulator in a Seagull Chipmunk, so I might be getting there, albeit slowly! That said, I avoid chucking away otherwise good stuff if it will still do the job required even if alternatives might do it better, or differently. I’m just puzzled as to why so many of my NiMh cells appear to have deteriorated for no obvious reason when they are supposedly resistant to doing so. The head scratching continues......

Nigel, Many thanks. Some interesting points there. First off, before seeing your response, I was about to report that the previously mentioned and seemingly “eeekworthy” pack just hit 4v within a few minutes at only a 100ma discharge! It was last used only a few months back in my PT19, so it seems that, by sheer chance, I might have dodged a bullet, there! For the sheer hell of it, and out of pure curiousity, I’ve just put it into “Forming Charge” to see what happens and because it’s a process I’ve never used before! What concerns me is that I was regularly topping up before flight, noticing no obvious issue and ending up with a seemingly acceptable settled off load voltage of around 5.6 volts or more as with my other packs. Had this been a NiCd, I might be concluding “memory” effect but this is supposedly not an issue, of course, with NiMh is it? The pack has certainly never reached anything near the claimed 500 cycles nor is it anywhere near the claimed 10 year mortality limit! I’m currently baffled! On your first point, my use of the 4.8 volt/500mA was purely to determine and provide a safe amount of “headroom” by seeing at what level of discharge the voltage dropped to the nominal 4.8v value. As you will note, the best pack of the bunch, unused and the most recently purchased, went down to 592mah i.e. almost 60% discharge (White/2000 cycle) which is way better than even the best of the rest at 38% discharge (Blue/500 cycle) and the former seems to be favourably comparable to the results that you have obtained from your packs, presumably 2000mah cells?. On your point about Lite versus Standard, these just happened to be what I saw available at the time and my choice had no other technical basis other than capacity. Also, in practice, as I mentioned in another thread somewhere, I considered that there was little or no advantage, in practice, to using higher capacity as I rarely have more than three or four flights with any given model on any given day. I was also mindful of the fact that 2000mah of a given size will have higher resistance and less current/volt drop capability than 1000mah although again, in practice, and in view of your comments, it is something that I might reconsider. All of that said, I remain puzzled by the seeming deterioration considering that Eneloops are supposedly the most robust and least fussy of cells in terms of storage and general use. Once again, many thanks for your input. I will report back further on the outcome of my “experiments” in due course, for those who might be interested! At the moment, I’m not sure if my presumed vigilance in keeping an eye on the health of my cells has been sufficient or can be improved upon in some way! Seems I certainly cannot rely on just regularly charging ‘em up or checking pre-flight voltage! I’m also wondering how many models have bitten the dust, over the years, due to batteries that were seemingly okay but weren’t! All of my crashes have happened for other reasons!

I have a total of 9 Overlander, Eneloop Lite Rx packs, of varying vintages, some never used but merely stored. I have 7 AA 1000mah Rx packs, 3 of which are White cells (2100 cycle?) and 4 Blue (500 cycle?). Of the above 7, 2 of the White cells and 2 Blue were cycled and tested in April of 2018. I also have 2 AAA 800mah packs, both White cells, that underwent the same process at the same time. So, a mixed bag of used, unused, tested and non tested in varying combinations! Feeling that it was high time to check/re-check all batteries, I elected to discharge all AAs down to 4v at 100mA, AAAs at 80mA and recharge at the same rates before then applying a 0.5C discharge load with my I-charger cut-off set to 4.8v. A very long process but the results were interesting, to say the least! Immediately prior to the 0.5C load test, all AAs were between 5.5 and 5.7 volts with the 2 AAAs at 5.4v and 5.7v. Discharge time for the unused and newest AA (White) pack was 1hr 10mins (592mah discharge). Excellent! And a useful yardstick? However..... Discharge time for 5 of the AAs (White And Blue) varied between 37 mins (314mah) and 46 mins (386mah). Fairly even but a little worrying compared to the above result! It gets worse....! Discharge time for the remaining (and fairly recently used!) pack was 1 minute! EEEK! The AAAs came out at 18 and 20 minutes (124/139mah). So........ Firstly, at this point, there seems to be no obvious correlation, in general, within this “mixed bag” of “same make” Rx packs to explain the results, unless I’m missing something. Secondly, there appears to have been a widespread deterioration in expected performance for reasons which I have yet to determine. Thirdly, in at least one case here, it seems that a fully charged, in-service, not very old, battery at 5.5v might be less trustworthy than I thought it was! Like most, I almost always fully charge Rx packs before use unless I know (or thought I knew!) how much safe flying time is left in the pack. Since purchasing a modern charger some years ago, on my return to the hobby, I have also made full use of the information it provides particularly when recharging and regarding how much capacity has been used after flying sessions. My models seem to be using no more than about 70 -80 mah per flight but a 0.5C load check seemed like a reasonable test value to include some “headroom” for test purposes. With one possible exception (!), I’m not ready to scrap any of my packs just yet until I’ve done some more “experimentation” to see if I can improve or revive them. There seem to be a number of views on this process on line but any additional input, or comment, from folks on this forum would be most welcome.

Posted by Nigel R on 12/08/2020 14:41:29: Claimed C ratings... trouble is, you don't get told what that limit actually means. 20C before a slight decrease in capacity will occur... or 20C before fire breaks out in a cell... The former for marketing purposes, the latter in reality, of course! Silly boy. 😊

TonyS, Referring back to your original post, would I be correct to assume that the model was originally okay or has this always been an issue? You also said that “everything” you put in is being wrecked. Do you mean just different batteries or have you replaced other components? Even my very limited knowledge of electric models suggests that it is, primarily, the ESC that needs adequate airflow rather than the battery. On reflection, I agree with those who suggest a power check (both watts and current) to begin with to see if the figures are what they should be or are excessive. You can then determine whether or not you are using a battery of too low a C rating or whether you have a problem elsewhere. No point in buying and fitting a higher C rating battery if it is merely masking a fault! Edited By Keith Miles 2 on 12/08/2020 13:53:41

Posted by Richard Clark 2 on 12/08/2020 11:33:53 It seems to fly very well. Sounds like it might fry very well, too!

Posted by TonyS on 12/08/2020 07:20:02: Thanks everyone. it’s frustrating that almost anything I’ve put in this plane is getting wrecked. I do manage throttle and only have it running ‘flat out’ on WOT for a few seconds at a time. Proving to be expensive flying. I’m wondering whether cheap ESCs or motors are more likely to damage batteries 🤔 I know next to nothing about EDFs but an experienced colleague has one, bought new, that has eaten two or three motors and a fan in fairly quick succession and for no immediately obvious reason. Not sure about the batteries, though. He, too, is not a happy chappie! It does make one wonder if a few designs are inherently flawed and/or not properly tested before they enter the market. Good luck with the battery upgrade. Certainly worth trying. Don’t buy too many just yet, though!

Posted by McG 6969 on 11/08/2020 20:57:08: Keith M2, ... don't never ever post "an attempt at satire", please... ... even if by chance "some may have got it"... ... most are too 'grumpy' to get it anyhow... On a side note, 'révolution' is feminine in French... the same as 'barricade' or certainly 'guillotine'... ... so, next time it should be "Vive LA révolution", please... Cheers & keep 'cool', all Chris Point taken. And well spotted. Apologies to the ladies. I passed German and failed French.

I wish to publicly apologise for my attempt at satire (although, hopefully, some may have got it!). And, personally, I’m far more concerned about Covid19 and not being able to make a brew in the clubhouse!

Yeh, let’s blame the government, club committees, BMFA and those malevolent and irresponsible drone fliers! Let’s also openly announce our intention to ignore the law and risk a fine but perhaps saving 9 quid to buy a cheap servo or, maybe, a Chicken Balti with Pilau Rice and a Plain Nan? And let us never accept responsibility for our personal actions or consider their possible effects on others. Vive le revolution! 😊

Posted by Barrie Lever on 11/08/2020 08:25:57: Keith Of course Futaba, but Paul had not listed Futaba as deceased. Yes, sorry. Was adding to your response about YS and Multiplex, out of context! Can I add Irvine, then?

Posted by Barrie Lever on 11/08/2020 00:03:55: Posted by Paul Marsh on 10/08/2020 20:51:56: In the past few years, we have lost ASP, SC, Magnum,Thunder Tiger, Super Tigre, YS, to name a few, and JR Radio, Hitec (as in Transmitters), Multiplex. Even most OS Engines are not made anymore... Paul YS and Multiplex are still going strong B. And Futaba, of course!

Excellent post, my friend. Edited By Keith Miles 2 on 10/08/2020 23:46:26

The biggest threat to the future of the hobby, in my view, is a lack of newcomers, particularly youngsters, rather than anything else. Dwindling demand will always result in dwindling supply. All we can do is enjoy and support what we have while we still have it!

Posted by Doc Marten on 10/08/2020 20:46:43: Debatable maybe, but off topic, regardless of the side you're on. Maybe start a different thread for this? Let the thread get back on topic eh?.....I know how much you hate thread drift. Edited By Doc Marten on 10/08/2020 20:52:37 PM sent.

Posted by Doc Marten on 10/08/2020 20:09:26: .....or just use masking tape and write the ID by hand, Thread drift ........Oh the irony! Again, debatable. I’m on the other side of the argument on this one as you noticed! 😊 And having read the requirements, masking tape might, indeed, comply as, whilst requiring that the ID be “secure” it is also recommended that it be removable should your ID change! I do enjoy a laugh and look forward to seeing the various permutations and interpretations!

Serious suggestion for our returnee, and others, for compliance with the new rules (as at least one fellow flyer has done) is to buy a Dymo labeller and, preferably perhaps, one that prints onto clear tape? Yes, more expense and no government refund!