LittleBob

I am tending to standadize on 5 cell 2500 mah Eneloope batteries for my receiver pack. I use 2 of them in parallel through 2 switches.

I know many people have different views on what to use and that is fine with me

I read somewhere that you should not charge Eneloope above 0.3 amp. Which takes quite a long time. Is this max of 0.30 amp accurate do people think or do they go above this

Thanks

Bob

LittleBob

This would sort of imply that you can charge at higher than the 0.3 amp Am I correct

Also just talked to a friend (A bit of a battery bore) and he has a new pack with him with an overlander Sticker that says:

Standard Charge 200 mah or Fast charge 2000 mah.

I know the fast charge will shorten their life but sometimes needs must. Perchance I will go at say 800 mah

http://www.eneloop.info/fileadmin/ED...data_sheet.pdf

Vincent

My Feedback: (61)

I typically use 1/2amp charge but have gone up to 1amp with no problems many times.
Vin...

LittleBob

Thanks for the info

Bob

marquisvns

I have a couple of packs for my 12x, these are the ones from Chad, great packs hold charge for weeks even with some use. My problem is that I couldn't get my new Hitec X4 to charge it properly at 300mA, it will complete at around 800mAh, the only way for this charger to fully charge my depleted pack is to dial it up to 1 or 1.5 amp. What can I adjust on my X4 for it to be able fully charge these packs at lower current?

Also, would an original JR charger at 250mA charge these packs properly? I have done it a few times seem to work ok.

Thanks in advance for your input!

Barry

Boomerang1

What charger are you guys using?

Both chargers I have used tend to false peak on these cells, current charger is
the Imax B6 (same as Hitec X2).

Also if you do a discharge test what do you set as the cell low cutoff voltage?

Any other hints? - John.

marquisvns

Just got this info from the manual:
NiMH default: 7mV
NiCD default: 12mV

the range could be dialed from 5 to 20mV, the higher the trigger voltage the more dangerous of overcharging.... where do you guys have yours set at to properly and fully charge at 300mAh?

Barry

SinCityJets

I strongly urge anyone charging eneloops NOT to go over 500mah, preferably 300mah. You WILL shorten their lifespan if you do.

Thanks.

Chad

KC36330

i bought my 12x pack from BVM, it came with an insturction sheet that recommended charging at 750 mAh, that's what i use, they have several hundred charges on them now and they still work as good today as they did when i got them a few yrs ago. i get close to 15 hrs of transmitter ON time per charge.

Xairflyer

My Feedback: (1)

I have been using them now for about four years I have about 30 4 cell packs.
I charge them at 1A if you charge nimh/enloopes at low rates they will not peak properly and most of the time get too hot and be overcharged which is what kills nimh packs.

Recently I have started using the temp probe that comes with four button chargers, that way you can't over charge them.

5-7mv is best for nimh

Xairflyer

My Feedback: (1)

Forgot to add nimh start to get warm when reaching full charge, if it is not warm it is not fully charged.

SinCityJets

Not true......not even close actually

Tom Antlfinger

My Feedback: (24)

Hi Chad:

Not sure what you mean by shortening life over 500ma. I am still using the packs you sold to me for my 12X, actually just after you first started selling them. Can't remember if that was 2008 or 2009. So your packs have held up close to 4 years. Still capacity discharge to 1950-2050 maH.

I always charge at 1 amp with an Orbit Pocketlader with the peak drop set to 5mv.

I have plotted the charge cycles on my Orbit PocketLader charger which outputs to my computer. I have found that 5mv peak gives the sharpest cutoff, no matter what the charge rate from 250ma up to 2000ma. Unfortunately, many chargers are either set to the old standard of 8mv for NiMh and 12mv for NiCd, with no way of adjusting that parameter. That leads to a peaking error, in that the charge algorithm delays the shutoff and the overcharge begins. This is most noticeable at the very low charge rates of 250-300ma.

I remember battery guru, Red Scholefield, talking about this false peaking of NiMh years back.

I do take good care of my cells, exercising them regularly during the 4-5 months of winter, discharging 1000maH after a full charge, keeping them at about 68F, not stored below freezing, and keeping them at full charge when in storage as opposed to A123 and LiPo's that do better at about 70% storage charge. I do this every 2 weeks during down time.

I suspect that life shortening may be the result of false peaking/overcharge, rather than simply the higher charge rate itself. No where in Sanyo's literature can I find that charging at C/2 or 1 amp will seriously shorten life.

Tom

SinCityJets

I agree Tom, this may be the cause. With my CellPro multi4, 300 seems to produce the best charge without the packs over-heating.

joeflyer

My Feedback: (48)

Here's what I'm using on my Imax B6 charger for Eneloops:

Charge 300 mah
Peak Trigger 5mv
Discharge 400 mah
Cell Cutoff 1.0 v/cell

So far that seems to be working well.

Joe

JPMacG

My Feedback: (2)

I don't know what to make of this, but Dave at RadicalRC recommends charging at low rates. RadicalRC was one of the first companies to sell Eneloop packs to the RC community. His advice has generally been spot on, but in this case I don't know what to say.

http://www.radicalrc.com/search/eneloop

retransit

My Feedback: (18)

I charge eneloops at 1C. No problems encountered. I use a Triton 2EQ charger. You do not want to overheat the batteries. NiCd's are more forgiving but you have to deal with larger cells at larger capacities and also the dreaded memory effect.

See:
http://www.eneloop.info/fileadmin/ED...data_sheet.pdf

Bob

Xairflyer

My Feedback: (1)

Go to the eneloop website and download the data sheet, it states a maximum charge of 2000ma.
Also I have a Sanyo made charger that states 2000ma max and will charger 4AA Eneloop loose cells in about 70mins from flat.

I have done loads of tests on Eneloop/Instant cells as I was fed up with Nimh chargers false peaking & over heating batteries.

I consistently found that low charge rates (200-500ma) on 2000mah and above Nimh cells, failed to charge properly, most peak detect chargers cant detect the peak drop off properly if the charge rate is too low, resulting in batteries being less than 75% charged or getting over charged (too hot).

And Yes the temp will rise when the battery is charged and any eneloop cells I have remove from my Sanyo branded and Specifically made eneloop charger are warm (5-15deg above ambient) when the charge is complete.

This is how I first discovered how temperature determines completeness of charge as I connected a temp probe to numerous single cells and monitored them right through the charge.

The temp of the stayed at close to ambient until about the last ten minutes when it started to rise very slowly, then at about 3mins from the end the temp started to rise more steeply.

Any Guys that race RC Cars will tell you about Chargers with Temp probes fitted to detect full charge, many of these were around before we had peak detecting chargers.

I have found that different Nimh cells perform differently, I use different settings for my Eneloop/Instant cells to my sub C nimh packs which can take a lot more abuse.

I now have started fitting temp probe to each battery pack in the model and Packs that I charge externally I just set them on top of a temp probe.
I set my Eneloops at 6mv and the temp cut off at 10deg above ambient. Charged at 1A

LittleBob

So many different opinions

I also found the Sanyo site and it deff says that you can fast charge at 2000 ma (2 Amps)

Xairflyer

My Feedback: (1)

If your packs are still cold when the charger has cut off then it has false peaked.

A friend also thought his packs were done because even when he fully discharged them he could never put more than 1200ma back in.
It was a simple case of the charger false peaking.

Nimh batteries are not like nicads which prefer a slow charge, you can charge a Nicad at 1ma it will just take longer to get there but will charge. Nimh don't properly charge anything below C/10

rmh

This is pretty much in line with the Sanyo charger.
Using them as a receiver pack , really is not a great idea UNLESS you have a model which does not have large peak draw.
If you do not have a in line meter which can be used to detect loads from each and total servo loads - you really can't tell what the actual loads may be
A failure -in flight may be the result

Xairflyer

My Feedback: (1)

I have only ever used them with models using standard servos, no AA nimh pack should be used with hi torque servos, these you need to use sub C's, A123 or lipos

JPMacG

My Feedback: (2)

The packs heat because once they are fully charged the power from the charger is converted to heat. The rise in temperature is obvious to the touch at high charge rates. But at low charge rates the temperature rise is smaller (because the power being dissapated is less) and can be imperceptable.

Terminating the charge by temperature change seems like a good practice to me, althorugh long-term heating is probably not good for the cells. Peak detect is not so reliable, being that the dip in voltage at peak is so small for NiMH chemistry. An out-of-family cell or a slight change in contact resistance at a connector can cause a false peak.

I don't mind the long charge times, so I charge at 80 mA for a set time (like 30 hours). I may be overcharging, but the cells apparently can handle low-rate overcharging (heating). My packs are several years old and still going strong with no significant change in capacity. Right or wrong, that is what I have been doing. Your results may be different.

retransit

My Feedback: (18)

Are you saying to never use NiMH's with high torque servos, or do you mean to say, use high capacity/energy cells with high torque servos? Is you base for capacity above, say, 4000 mah's?

Bob

Xairflyer

My Feedback: (1)

Only AA size Nimh batteries, they cant take big loads, and a stalled servo will pull the battery right down where as Sub C nimh cells can supply big amps and the servo may burn out but you should still have power in the battery to run Receiver etc.

Sub C's are a very good battery for RC use and great when you need weight, so long as you remember that normal Nimh have a fairly high discharge rate when not being used especially the large capacity ones like 5000's.

I know A123's are a great battery but the voltage does not always suit, what I would love to see coming out is 4000ma Sub C eneloops.