Am I just unlucky

[Myron Beaumont]

Same old story Isn't it ? when I 've bought 4 gallons of fuel ,(18 litres) I don't recall any one of them being a dud .Sorry ,just me .

[Vecchio Austriaco]

Best performance I got from

Hyperion - on 4 batteries 3cell 2200 I am already at 60 recharges and they work like new - always charged with 4C (5allowed) never lower than 10%

Hacker LiFe - I am just on 25 cycles but I hope they go far above 100

Worst from Zippy (didn't count the cycles - but single cells died in 3 different packs within one year)

and (surprise ) Kokam. Problems on 2 batteries with 2 cells 1800 (receiver supply). Take awfully long to recharge, balancing problem.

I wonder what happens after a long storage time - lets say 6 month. Will all be ruined because of self discharge? Any experience?

 

Background: I move house and all stuff goes for some month in storage. But I still didn't pack the batteries - may be I take them with me just to monitor and recharge (to 60%) them from time to time.

Edited By Vecchio Austriaco on 07/10/2010 17:14:16

[Chris Bott - Moderator]

Oh I've seen many a modeller struggling with dud fuel..   but that's a whole new argument lol

[Wingman]

Vecchio - LiPos don't self discharge so they'll be fine after 6 months.

[Erfolg]

Chris

 

We must have passed in the street. It was some cheap (so the argument went on return)  fuel, it had been in stock a tad long and had absorbed some water, did not know until I got home. Poor running.

 

Oh no the same is happening to my Cyno.

 

Both are real and true modelling stories.

[Myron Beaumont]

Chris

Ah! but from your brief profile I presume you are one of the new age 100% 'lekky men. You can distil fuel that's "gone off" nevertheless  .Then again maybe it would alter your brain & you'd end up buying more batteries etc 

[Chris Bott - Moderator]

Erfolg/Myron

 

I've really been resisting this but Tim and David know how hard I find it not to slip this in..

I'm a long term A123 user (probably the longest in the UK).

I don't have fuel go off, I don't get deadsticks, my batteries last many times the number of cycles that the average LiPo does and they are intrinsically safe too due to the chemistry.

Add to that the excellent performance, and I'll stick to them for the time being  

[Myron Beaumont]

Chris

Having read Timbos article and others,I can understand where you're coming from & Life po4's as well.We live & learn ,but if they've been around so long as you say ,why aren't more peeps using them apart from short nosed WW1 biplane scale modellers instead of dead weight  .? (re:Timbos ill fated bipe ) I've recently gone all "Instants " for my radio gear 'cos of what I've read on the forum. Good move -Don't worry anymore about them going flat. What is next I wonder ? By the way ,I don't get "dead sticks 'cos my engines are set up correctly & my fuel (some of which is three years old) has never "gone off " as you put it .(Any more than petrol does in your car !)

[Chris Bott - Moderator]

Hi Myron, I did push the idea really hard on here for a good two years but very few people have taken up using these cells as you say.

 

Timbo's article will help spread the word. Lot's of good info in there isn't there and some pictures of some nice models and a nice hand

 

There have always been a few drawbacks:-

1. They are heavier for the same capacity as LiPo's. Having said that, you should compare "useable" capacity. This makes them much closer.

2. There are very few sizes.

3. They appear expensive. However, considering the longevity, the cost of ownership comes out very favourable. If you can get hold of the right dewalt packs to disassemble they work out at a much better price.

4. Chargers weren't always available. I made my own for the first couple of years.

5. Low voltage cutoff needs careful handlin. 

 

On the plus side, fast charge, safety, longevity, same power towards the end of charge as at the start. Many people in my club use them now. Mostly in 40-50 sized I/C models.

 

I have the following on A123's:-

Seagull Sea Fury  (in Tim's article) on 6S2P

YT Iconic (my hand and pack in Tim's article) on 6S1P

DB Tiger Moth on 6S1P

DB Cirrus Moth on 6S1PYT 3Demon on 6S1P

RC World 3Styla on 6S1P  This is on Skis for the winter.

Balsacraft Spitfire on 4S1P

YT P51 Funfighter on 4S1P 

 

As you can see I have many models on similar packs. This means I can just use a small number of packs and charge one while another is flying. 

 

ooh, my lovely ASM DH88 went really well on 6S1P in each nacelle (until it's demise - it will fly again, just not sure when.. 

 

 

 

[Myron Beaumont]

Chris

I'm getting the (your) message . I wonder what would happen if they had just come onto the scene very recently? 'Do you think peeps would buy Lipos as they do ?The voltage / weight issues would hardly be relevant would they ? Isn't it a bit like "Instants/Vapex's versus Nimh's

Once you've got them -they are the bees knees .for the job .

[Chris Bott - Moderator]

No I don't think so Myron. LiPo's have plenty of advantages.

 

There are dozens of different sizes for different applications.

They pack the best capacity to weight ratio.

The fast charge advantage has gone now too with plenty of fast charge LiPo's available.

 

It's horses for courses really... 

[Herri]

I have had two Team Orion 35C 3S packs go on me within a couple of months.

 

The first time it happened I put it down to experience and threw the pack.

 

Last weekend it happened again (same a/c different capacity pack) when the aircraft nosed over on take off. (same as last time)

I opened a thread but no-one has any explaination. I didnt touch the pack or open it to find out why one cell was dud as I was afraid the shop wouldnt take it back.

Anyway today I took it back and they are going to send it in and I shoud get a new one.

Cheers

Herri 

 

[Vecchio Austriaco]

Myron and Chris,

 

Today you get LiFePo4s in packs which are equal to LiPos from size point of view. So you do not have the advantage of the metal cup - but you do have the advantage that the cells are less delicate when it comes to lowvoltages. And the shpould allow more charging cycles than a LiPo. Look at the article in the special edition - they are mentioned at the end of the article. I fly currently my Sebart Sukhoi 29e 30 size only with 4cell LiFePo4 from Hacker - also with higher capacity (3100) then originally suggested for this plane. (2200 3cell recommended) In some situations  the extra weight is an advantage - as for instance if you fly in the windy conditions of this group of islands called the UK...

[Danny Fenton]

Good news on the pack Herri, it would be nice to know what happened in the end. There was a problem a while ago where balance leads would snap right up against the JST connector due to all the tugging plugging in and out of chargers. If this snapped lead touches any of the other connector the result doesn't bear thinking about. If it comes adrift inside the pack its less likely to short against others.

 

I know at the time you said one cell was at zero volts and the others at 4, what was the overall pack voltage on the esc supply cable? Did you measure it by any chance?

 

[Chris Bott - Moderator]

Hi Vecchio

 

I'm glad you have found some good "soft" LiFe's.  This is an interesting development. Various people have tried non A123 LiFe's in the past and they have been very poor in performance.

 

The A123 LiFe's  not only use this intrinsically safe chemistry, but they are also endowed with "nano" particles which give much more surface area and allow the huge currents both in charge and discharge.

 

 

[Vecchio Austriaco]

Chris,

 

I let you (and the forum) know when I pass the first 100 cycles with these batteries. Hope I don't destroy my plane before that ....

[Mart61]

These are what I've been using:

 

Linky

 

They suit me just fine and are not that much more than going to HK (and you get them in around 2 days)

 

Edited By Mart61 on 07/10/2010 21:00:33

[TonyS]

David,

I've bought Overlander LiPo batteries almost exclusively since I started flying. The first time by accident and thereafter as they seemed to be doing the job so there seemed no point in changing.

These are a bit more expensive than other brands but I have really abused mine and still get 97% charge. By abuse I mean very regularly discharging to 2 or 3% capacity.

I haven't kept a tally but the 1700 mAh Extreme 30C 3S packs that went into my Starmax Panther must have cycled around 30 to 40 times. They were never treated nicely at the beginning (several full charge discharge cycles as some suggest), I have never deliberately allowed for extra cooling in the airframes,  as I say, I've regularly discharged until virtually dead, bounced in several crashes and they're still going strong.

 

Just did a quick inventory and the only other batteries I have are the Parkzone supplied ones that came with certain models.

 

I notice you've bought a few but don't seem to have had any issues with the Overlanders.. 

 

The guys at the club swear by other brands....who knows 

[Herri]

Posted by Danny Fenton on 07/10/2010 20:18:00:

Good news on the pack Herri, it would be nice to know what happened in the end. There was a problem a while ago where balance leads would snap right up against the JST connector due to all the tugging plugging in and out of chargers. If this snapped lead touches any of the other connector the result doesn't bear thinking about. If it comes adrift inside the pack its less likely to short against others.

 

I know at the time you said one cell was at zero volts and the others at 4, what was the overall pack voltage on the esc supply cable? Did you measure it by any chance?

 

 It measured about 0.4 v if I remember correctly. I thought it strange as when you first touched the terminals it read 0 v but if I held the multimeter leads on, it went up to give a tiny voltage.

Cheers

Herri

 

[Tom Foreman]

David, I always check my packs individual cell voltage before I fly and have sometimes noticed cells out of balance, don't know why, I use a Cell Pro balance charger. Anyway if you flew the pack when its out of balance its conceivable that one of the cells could have been drained before all the others, something to watch out for.

 

Tom 

[Tony Smith 7]

Posted by Chris Bott on 07/10/2010 17:36:25:

Erfolg/Myron

 

I've really been resisting this but Tim and David know how hard I find it not to slip this in..

I'm a long term A123 user (probably the longest in the UK).

I don't have fuel go off, I don't get deadsticks, my batteries last many times the number of cycles that the average LiPo does and they are intrinsically safe too due to the chemistry.

Add to that the excellent performance, and I'll stick to them for the time being  

Hi, could you point me to a supplier for A123 power packs, or cells suitable for making up?  I need to jump ship from NiMH, but haven't done so yet.  I think I'd trade a bit of weight for greater tolerance compared to Lipos.  

 

Thanks,

[Danny Fenton]

Hi Tony, I have used electricwingman the last few times.

 

Electricwingman

 

Cheers

Danny

[David Ashby - Moderator]

New Hacker pack arrived from the chaps at Area 51 Distribution, I asked if they would send one of the new Hacker 4000mAh 4S lite's which they happily did so top marks there.

[Peter Beeney]

   David,
           I also think there is an issue with some packs as of new. That’s certainly always been the case with nickel cells, but perhaps not so noticeable, maybe because the loads are not so great in many cases.
   A flying mate very recently bought three 2,200 mAh 3S packs, I think from HK, and I can’t remember the make. Two charged fine, but his charger rejected the third. So another friend tried it on his charger, but it refused to balance. He’d more or less given it up a no hoper, so I said I would have a little tamper with it.
   I checked the cell voltages, two were at 4.2V, and one, an end cell, at 4.0V. I charged this from an independent source, at about 150 mA, for quite a while until the voltage rose to 4.3V. Then a discharge at 2A yielded 2,400 mAh, so not a lot wrong with the capacity. The recharge resulted in the end cell being low again, so I did the same trick again and recharged it, gave it back and said ‘ Try it out, but I don’t think it will be a great success.’ To my surprise, when I next saw him he said it was charging and balancing ok; but I will not be surprised if it very quickly fails, indeed very much more surprised if it continues to perform!
   You mentioned the failing pack taking the model with it, does this mean one cell totally failed in flight? As you suggested, is this now beginning to happen? It would appear that from other recent comments this might be the case. Way back I had two of the first cells, small capacity, which I was trying as a rx supply with a regulator. One of those suddenly died overnight, it didn’t go completely open circuit, just zero voltage. That rather put the brakes on that little experiment at the time.
   Is it any sort of an idea if someone might like to try to establish exactly what is going on, if possible? Would that be worthwhile? Also you might run a battery ‘problem pool’? Is that a thought? I’ve always felt that if something like this was well advertised it would quickly become inundated with information; but to give reasonably accurate result, you would have to have an indication of all the successful flights as well, and an indication of the number of packs sold, that would be a vast amount of information!

   With hindsight I should have perhaps looked a bit deeper into the little problem above. A few cycles on just the one cell may have given me a bit more info. If it comes back, as I suspect it will, then I will give it a little kicking!                               PB

[Allan Bowker]

Perhaps we should have an annual RCM&E award for the unluckiest person.

 

Can I be nominated for the rollercoaster ride I'm having with my WOT 4 Foam-E ?