Topic: SANYO ENELOOP NiMH BATTERIES

There seems to be fairly widespread confusion allied to conflicting advice where Sanyo Eneloop's are in the frame - so

From Sanyo's website (not Shultz - 'my mate sez'....'I've always thought...etc etc)!


1     Sanyo Eneloop AA cells are 2000 mAh - AAA cells are 800 mAh (capacities)

2     When fully charged they MAY...maintain UP TO....75% of that charge for UP TO....3 years (lots of maybe's - up-to's and so on there)!

3     Temperature has an effect on eneloop's performance. If it is too hot, the high temperature could cause the battery to discharge at a more rapid rate. On the other hand, eneloop works better than alkaline, and other rechargeable batteries in freezing temperatures!

4      CHARGING (this seems to be where a major confusion lies - forget the charger shortfalls or instructions, it's not Sanyo's fault if your Shultz or whoever's charger won't do the job properly) - so :-

How long does it take to charge an eneloop battery in the eneloop 2-position compact charger? - Answer From 2 to 4 hours. i.e suggesting that a flat battery will take four hours - 4 x 500 mA = 2000, so Sanyo clearly would prefer you to charge their batteries at half an amp max!

Can I use a "Quick Charger" to charge an eneloop battery? - Answer Though it is possible to charge an eneloop battery in a "Quick Charger", it is not recommended. - Couldn't be clearer - NOT recommended by the folks who make the things and they should know! - they cover that with "We recommend charging eneloop batteries in a NiMh charger that is 2 hours or more. Charging eneloop batteries in a "Quick Charger" can reduce the overall life of the battery. It is strongly recommended to use eneloop, Sanyo or Sanyo NiMh battery chargers. We only warrant eneloop if used with an eneloop, Sanyo or Sanyo NiMh battery charger.

Obviously they want you to use their charger and obviously any other charger that can deliver half an amp will charge your Eneloop cells in four hours or less - if Sanyo were happy with you charging cells at 1C (i.e. in just an hour) then their own charger would reflect that - it doesn't!

Finally - STORAGE - "The best place to story any battery, rechargeable or not, is in a dry cool place, such as a drawer, under your bed or in a closet. Keep them away from the possibility of coming in contact with extreme high heat. It is recommended to store them at or around 24 degrees Celsius. It is not recommended to store them in a freezer, (as it is best to keep materials of this nature away from food products blah blah blah etc.....nanny culture kicking in there Mr Sanyo).
"


At the end of the day the Eneloop is 'just another NiMH - it's a later generation and has improved qualities, but there's nothing magic about it - if you want to cycle it to check its performance then do so - that's exactly what you do when you used their full capacity - the advice about 'not cycling' is simply because there's no advantage (other than knowing how they're behaving once in a while) to doing so!

In short then - charge at half an amp or Less (less is fine....) - don't bother with cycling - don't use auto or peak detect chargers that are known to have 'iffy' behaviour on NiMH's or if you do check that the thing hasn't false peaked! If it's very hot or freezing cold, expect reduced performance (capacity)!







 

Hi enginetorque
Are we talking about the Instant Packs ?.
Never had probs with them untill Vapourtech or whatever they called change them to the red packs.
I had 2 brand new AA packs completely fail last week during flight, dont think I can trust them again.
Not had probs with any other packs.
Cost me my new Filip Highlander  

Just a couple of points I would take issue with:

This part:

How long does it take to charge an eneloop battery in the eneloop 2-position compact charger? - Answer From 2 to 4 hours. i.e suggesting that a flat battery will take four hours - 4 x 500 mA = 2000,

Does not in any way imply your comment:

so Sanyo clearly would prefer you to charge their batteries at half an amp max!

All it actually says is that the specific charger refered to in the question is a 500mA charger - nothing says this is the maximum, prefered or recommended rate.

Secondly this bit:

Can I use a "Quick Charger" to charge an eneloop battery? - Answer Though it is possible to charge an eneloop battery in a "Quick Charger", it is not recommended. - Couldn't be clearer - NOT recommended by the folks who make the things and they should know! - they cover that with "We recommend charging eneloop batteries in a NiMh charger that is 2 hours or more. Charging eneloop batteries in a "Quick Charger" can reduce the overall life of the battery. It is strongly recommended to use eneloop, Sanyo or Sanyo NiMh battery chargers. We only warrant eneloop if used with an eneloop, Sanyo or Sanyo NiMh battery charger.

Talks about "Fast chargers" - most "Fast Chargers" charge at 5c or more (10A for a 2Ah cell).  In actual fact in this piece it clearly says "charge in 2 hours or less", showing that they are actually happy with a whole amp charge rateon the 2Ah cell, not the half amp which you claim is their stated maximum.

It pays to actually read what they said.

Finally:

It is not recommended to store them in a freezer, (as it is best to keep materials of this nature away from food products blah blah blah etc.....nanny culture kicking in there Mr Sanyo).

Actually this is a very important piece of advice, and is a long way from "nanny culture". NiMH batteries contain heavy metals and toxic substances in the electrolytes. They vent these substances when they change temperature, and getting these substances on foodstuffs is a very, very bad idea. Heavy metal poisoning is very, very nasty (ask cactus, who has suffered from it due to a lack of adequate safety culture at a former employer).

Please be a little more careful in distrubuting "authoritative" advice which can kill and cripple people, and even cause birth defects in unborn children.

PDR

Thanks for that, ET.

The sales blurb refers also to higher output current than with regular Nimhs.
Did you find anything on that?

Now then Mr Reiden - (just for your benefit..) Nanny state blah blah - OK for those who would prefer DIRECT from the horses mouth..................(sigh.......)!

http://www.eneloop.info/

I posted the thread as there is clearly confusion twixt charger instructions / behaviour and battery behaviour - it's not meant to be a 'definitive' on the ruddy things - if you want the square root of a jamjar approach then it's all out there on the net!

As for 'not eating heavy metals' - do us all a favour - we're only 'moderately stupid' (why I can tie my own shoelaces and everything..........)!

Tell you what folks - you do what you like with your sodding batteries - I'll do the same  

Dont be miffed Enginetorque, you post was all well-intentionned stuff but my own take is that you cant always take manufacturers data literally - for example take their advice (is this actually a quote?):

"The best place to store any battery, rechargeable or not, is in a dry cool place, such as a drawer, under your bed..."

Any battery?  So Sanyo's advice is to store Lipos under your bed???  

You have to remember that manufacturers are forced to stick very very much on the safe side of their own specs and have to pitch their instructions at a level that is perfectly safe for Joe Public, ie people who have no knowledge or experience of battery technologies...  whereas we have been using them exclusively for decades and our familiarity and experience has closely followed battery developments.  There can be few other hobbies so dependent on such frequent use and experience with rechargeable cells.

I'd suggest their maximum recommended charge rate is probably more to do with consumer safety than cell longevity or charge retention. I'd further suggest that we, as a group, almost certainly have more practical experience with rechargeables than any Sanyo employee!

Pillpopper -  those red cells aren't Instants. Vapextech make several different types of cells, Instants being just one of them.   Vapextech Instants are still green - confirm with Skirmish who distributes them.

All in my Humbrol opinion of course  

Cheers
Phil

Pillpopper -  those red cells aren't Instants. Vapextech make several different types of cells, Instants being just one of them.   Vapextech Instants are still green - confirm with Skirmish who distributes them.

Oh I see, I orded Instants and recieved these two new red packs, never had probs with instants, will stick with them and send red packs back.

I think that the Eneloops are fine. I just treat them in a sensible way, the same as I would with any other Nimh pack. Always charged mine at 1A and my little AAA's at 0.5A on a Schulze and haven't had a problem to date  but I put that all down to my £5.99 Ripmax load checker!!

Z

OK, I apologise - my comment was probably a little harsh. But a couple of years ago I lost a colleague to cadmium poisoning (the result of not washing his hands between handling cad-plated connectors and having his lunch sarnies) and it wasn't pretty. I did a lot of research into heavy-metal poisoning after that and was rather shocked at how easy it is to get contamaination onto food.

We handle a lot of toxic stuff in this hobby and I beg my friends to PLEASE keep modelling stuff and foodstuff completely seperate - never put epoxy, cyano, paint etc etc into the household fridge or freezer. If you *need* cold storage for modelling stuff then go through the small-ads in the local paper for a crusty old second-hand fridge (you can usually get one for free if you collect it) and keep it in the garage. And even if you do this remember NOT TO STORE BEER IN IT as "emergency in-build refreshment!

Gosh this soap-box is high up - can someone get me a ladder or I'll be stuck up here all day...

PDR

Since yer up there can you clean my gutters please

Pillpopper -  those red cells aren't Instants. Vapextech make several different types of cells, Instants being just one of them.   Vapextech Instants are still green - confirm with Skirmish who distributes them.

Nearly Correct. 

The Vapextech Instants used to be entirely green but are now packaged in a predominantly silver with a green ellipse covering.
The red cells which are just a normal nimh are now a mixture of silver and red covering.
Vapextech do produce 2900mAh cells but they were not considered suitable for RC applications so they use a 2600mAh cell that charges more reliably and can provide more current when needed.

And yet the last couple of made up Vapex Instants  battery packs from http://www.component-shop.co.uk have been solid white with no other distinguishing feature 

And yet the last couple of made up Vapex Instants  battery packs from http://www.component-shop.co.uk have been solid white with no other distinguishing feature 

I have to ask how you can be certain then that they are Vapextech Instants? I've never had any like that and they've always had Vapextech branding on them.

Hi enginetorque
Are we talking about the Instant Packs ?.
Never had probs with them untill Vapourtech or whatever they called change them to the red packs.
I had 2 brand new AA packs completely fail last week during flight, dont think I can trust them again.
Not had probs with any other packs.
Cost me my new Filip Highlander  

Vapextech red/orange packs and Instants green packs supplied by Vapextech are two different packs.

Green Instants are great. I had two or three orange/red packs labelled Vapextech and trashed them as JUNK.

I think that the Eneloops are fine. I just treat them in a sensible way, the same as I would with any other Nimh pack. Always charged mine at 1A and my little AAA's at 0.5A on a Schulze and haven't had a problem to date  but I put that all down to my £5.99 Ripmax load checker!!

Z

I don't know what size batteries your'e talking about there, Zim, but if your'e using a Schulze and you time your charging, OK.  But, if your'e using the peak-detection cut-off feature, remember what Schulze said in their email to me (see "Zen.." thread):  not less than 0.75C !

maybe the much vaunted schulze should write some software that works properly then........

Eh, I'm happy using .75C..

If I recall correctly my Shulze says min 1c.

But it seems to work happily at less.

What I thought were false peaks on some packs a few years ago turned out to be packs that had cells going out of balance.

With tese packs It would do a imitation of Billy goat gruff, on that old bridge.


Trip,trip,trip..

Mike, you must have missed this then:

"So I asked Schulze the following:

We have a big argument raging on our RC forums about charge rates, particularly for Sanyo Eneloop and Vapextech INSTANT battery types used as receiver battery packs, and I was wondering if we could have some advice, please?

 
As I am an owner of two Chamaleon ISL 6 changers, I have always charged NiMh batteries (when I do not use the AUTO-C setting) at a rate of 1C, based on the specific advice given in your instruction manuals (Never less than 1C).  I regard Eneloops and INSTANTS as NiMh also, so I also charge them at 1C.
 

Most members of the forum do not charge these batteries at such a high rate, they recommend anywhere from 0.3 to 0.6C, unless they are in a specific hurry.  Most believe that fast charging shortens battery life.

 
Your comments would be most appreciated!

 

..and got this reply:


thank you for asking us.
 
We charge the eneloop 2000 mAh with 0.75 C -> 1.5 A.
 
This is high enough for a reliable peak cut off.
 
If you want to learn more about this cell please check the eneloop web page.
Maybe they even have an engineering data book about this cell where such test had been made and published."

Within the link given in reply #4 the Performance Details for Discharge Current, Low Temperature & Voltage each have graphs in which the cells are charged at 2000mA using a neg delta peak of 10mV.
So it appears that Sanyo are happy to charge at 1C.   

If I recall correctly my Shulze says min 1c.

But it seems to work happily at less.

What I thought were false peaks on some packs a few years ago turned out to be packs that had cells going out of balance.

With tese packs It would do a imitation of Billy goat gruff, on that old bridge.


Trip,trip,trip..

Precisely my reason for the thread - that's the shortfall of the Shultze charger - nowt to do with the battery 

Precisely my reason for the thread - that's the shortfall of the Shultze charger - nowt to do with the battery 

Or perhaps a limitation of the delta-peak detection technique for low-current NiMH packs - the variance in signal is greater that the range of values that indicate the threshold.

But we knew this about NiMH cells, which is why most people recommend NIT using a delta-peak technique at low charge currents.

PDR

Or perhaps a limitation of the delta-peak detection technique for low-current NiMH packs - the variance in signal is greater that the range of values that indicate the threshold.

But we knew this about NiMH cells, which is why most people recommend NIT using a delta-peak technique at low charge currents.

PDR

Or, as Schulze put it:

Charging fewer than 4 cells at output 1: the
special 16-bit A/D converter is outstanding
accurate, but we cannot guarantee that the
charger will work correctly in this situation.
The charge termination may occur too early,
too late, not at all, or even perfectly correctly,
and the charge current will not approach
the maximum rate. The reason for
this is that the "kink" (peak) in the voltage
curve of fully charged high-capacity cells at
low currents is very slight (low).

Do I read this correctly, then? Charging at 1.5 amps should give a reliable peak cut-off, whereas charging at a lower rate will be unreliable?

i just charged one at 500mah.

i just charged one at 500mah.

You rebel you.  Living on the edge, huh?

Man, you guys need to get out more.

Man, you guys need to get out more.

Noooo, it's scary out there...

i'll try one at 200 for a "thrill" 

Do I read this correctly, then? Charging at 1.5 amps should give a reliable peak cut-off, whereas charging at a lower rate will be unreliable?

It is generally true that the "kick" in the cell voltage that is used to trigger the cut-off is more distinct and pronounced at higher currents. This is because the cell voltage when being charged at low currents varies anyway (it is a "noisy" signal), but higher charge currents allow the characteristic to be "seen" more easily. That's why a GP2200 pack can be safely charged with a delta-peak cut-off at 10A or more, but it will "falso peak" if you tried the same thing at 100mA.

PDR

Or perhaps a limitation of the delta-peak detection technique for low-current NiMH packs - the variance in signal is greater that the range of values that indicate the threshold.

But we knew this about NiMH cells, which is why most people recommend NIT using a delta-peak technique at low charge currents.

PDR

Yup - in a nutshell - peak detect and NiMH's - tenuous - I charge at a known current for a known time - which is why I never 'bully' my fast charges!

Any - old - way - this thread was posted on the back of poor old Paul losing a lovely aeroplane with a flat battery that his trusty Shultz had been telling him was charged - we now know it wasn't!

The Shultze charger is very much in the frame re the above - great charger for most applications but it's certainly seems to be less capable of determining delta peak on NiMH's than my 'cheapy' chargers - that Shultze confirm that (reading between the lines) should at least alert those using a Chameleon to that!

Again - Andrew Gibbs is a worthy reference source on Shultze Chameleons!

I did a cycle last night to check the capactiy of an eneloop pack.  It discharged at 0.18amp/hr and charged at 0.6amp/hr. This morning it had peaked when 1938 had gone in, which is pretty decent.

Also did a 1400 2/3a vapex pack which did over 1400.....

Anyway..... it's nice to check from time to time.......

I did a cycle last night to check the capactiy of an eneloop pack.  It discharged at 0.18amp/hr and charged at 0.6amp/hr. This morning it had peaked when 1938 had gone in, which is pretty decent.

What charger was it Tom?  Did you set the values manually?

As many have said already now, it has become apparent that the Eneloop should be treated as for any other AA NiMH pack and that involves 2 things:

1.    Charge at a fixed current that is suitable for peak detection on the charger in use.  For Schulze that may be higher than for other chargers, but that current still seems to be within the battery tolerances.

2.    A test discharge must be carried out occasionally to confirm the health of the pack.  I have 2 Eneloop packs that were in poor condition and both have been cycled back up to capacity (5 cycles required on each pack).  They are now sitting on a shelf and will be there for 4 weeks awaiting a test discharge to see what effect the cycling had on the cells.

It's basically like this one:
http://alshobbies.com/shop/lookupstock.php?pc=5727&Desc=

I have two actually they, were 70 quid at the time, but it has been money well spent.  I'm sure you can get the equivalent cheaper now.  I've never had a false peak (that I know of!) even with a cable that was about 2m long.  The software seems to work great for nimhs.

That being said I did find a couple of times that charging 2/3a at 100mah/hr didn't work (didn't peak).  But I never bother that low these days.  On those chargers you set the charge rate and the discharge rate to what you want, but it is automatic in the sense that it just stops when it peaks (or at the voltage level you set for a discharge only cycle).  Actually it doesn't go straight in at the set charge rate, I think it "builds up" (technical term) and sort of works it all out itself (more techie talk!) to the charge rate. Anyway, it works proper good like!

They are now sitting on a shelf and will be there for 4 weeks awaiting a test discharge to see what effect the cycling had on the cells.

hehe. yes it does take a while!  Usually I am woken in the night by strange bleeping sounds, telling me that it's done.

That one looks like the generic Bantam/GT Power/Emax etc ....
Slightly off topic but something I've pondered for a while, I think a huge improvement to to these chargers would be for manufacturers to provide a 3-wire charge lead instead of the two-wire supplied... as it stands they're sensing at the wrong end of a cable thats carrying appreciable current.  All decent bench supplies for example have remote sensing, even if the sense point is at the output terminal. Really good ones provide a completely separate sense lead that you connect to pos at the load.  For nimh/nicd we're looking for millivolt peaks... try passing an amp or two down a yard of chinese red & black twin, measure the drop & you'll see what I mean, the charger is looking for the peak on top of the standing drop, so the A/D is probably working in a small window of its range, and so lowering its resolution.   A 3-way lead with the sense taken from the battery connector might improve these cheap chargers no end IMHO.
For Lipos, some do remote sensing via the balance lead, but thats not an option for nimh/nicd.
Anyway, it was just a thought.
Phil

Some great info in this thread, keep it coming

Now i realise why i get loads of false peak charges on my Nimhs on my Shultze, I always try and keep the charge to a minimum so I don't stress the batteries, I need to bump up the charge rate a bit 

Steve

That one looks like the generic Bantam/GT Power/Emax etc ....

It has a 240v (and 110v) power supply though. I believe it is similar to the  graupner ultramat 14.
http://store.modelpower.co.uk/graupner-ultramat-14-plus-55-p.asp



It would be good if NiMhs had balance leads like lipos....... maybe......  

It would be good if NiMhs had balance leads like lipos....... maybe......  

True, if the cells aren't balanced, each cell in an nimh/nicd pack will peak at a slightly different time so the combined peak is smaller than expected, hence chargers occasionally missing the peak.

Trouble is, we seem to be obsessed with voltage balancing, when capacity balancing is what matters

Phil

I give up .  I think I'll just go fly a bit to forget all this stuff..

I give up .  I think I'll just go fly a bit to forget all this stuff..

Sorry          thats the best suggestion about batteries yet - go fly em!

Phil