Batteries for Canon EX 600 RT...

[Rienzphotoz]

the documentation warns against giving the batteries too much juice during recharging (ie, re-charging too fast)

i always set it to 700 (out of 1000)

i'm curious... if you use a re-charger that allows you to set the recharge rate, what rate do you use??

What does the document warning say, I mean the consequences of recharging fast?
I ask bcoz for the past 3+ years I've been using energizer fast recharger (30 mins) to recharge my eneloop batteries, and I threw way the manual a long time ago.

 

[Jimbo]

The maximum safe charge current for Sanyo Eneloop batteries without reducing service life is 1/2C, i.e. half the rated capacity in mA.
The maximum overall charge current according to the datasheets is 1C.
(1C does not mean 1 Coulomb, but 1 Capacity unit. This sometimes leads to confusion and frankly, I do not know why this unit was chosen.)

To sum it up:

For the white Eneloops (200mAh) recommended current ist btw 500 and 1000mA, max at 2000mA
for the black (XX) Eneloops (2500mAh) it is btw 500 and 1250mA, max at 2500mA.

Best results will be obtained with a modern electronically controlled fast charger that takes between 2 and 4 hours for a full charge cycle.
Very fast chargers (btw 1 and 2 hours) slightly reduce service life. If you accept having to buy new cells at a slightly higher rate, that should not be a problem, though.
For Eneloops especially, I would stay away from chargers that take less than an hour for a full charge (i.e. current more than 1C). They waste your cells and it would be wiser to just get a set of backup cells stored away readily charged.
Those chargers are from the days before low self discharging cells like Eneloop when you had to hastily top up your constantly discharging cells before you left the house. That is a thing from the past.

 

[Rienzphotoz]

The maximum safe charge current for Sanyo Eneloop batteries without reducing service life is 1/2C, i.e. half the rated capacity in mA.
The maximum overall charge current according to the datasheets is 1C.
(1C does not mean 1 Coulomb, but 1 Capacity unit. This sometimes leads to confusion and frankly, I do not know why this unit was chosen.)

To sum it up:

For the white Eneloops (200mAh) recommended current ist btw 500 and 1000mA, max at 2000mA
for the black (XX) Eneloops (2500mAh) it is btw 500 and 1250mA, max at 2500mA.

Best results will be obtained with a modern electronically controlled fast charger that takes between 2 and 4 hours for a full charge cycle.
Very fast chargers (btw 1 and 2 hours) slightly reduce service life. If you accept having to buy new cells at a slightly higher rate, that should not be a problem, though.
For Eneloops especially, I would stay away from chargers that take less than an hour for a full charge (i.e. current more than 1C). They waste your cells and it would be wiser to just get a set of backup cells stored away readily charged.
Those chargers are from the days before low self discharging cells like Eneloop when you had to hastily top up your constantly discharging cells before you left the house. That is a thing from the past.

Darn it, I'll have to get a new charger now ... oh well, since I've already messed with my eneloops charging them with a 30 minute charger for the last 3 years, I guess I'll just have to get new batteries and a new charger ... I'll wait for my current batteries to die and get new charger & batteries.

 

[romanr74]

What are the relevant parameters with Batteries? What's most important for good performance and fast recovery? I did some shooting on the weekend with my 600 RT, in programmed 5 second interwals: it first fired every second one, sometimes only every third. Is this what can be expected or do batteries make a relevant difference here?

 

[DB]

The maximum safe charge current for Sanyo Eneloop batteries without reducing service life is 1/2C, i.e. half the rated capacity in mA.
The maximum overall charge current according to the datasheets is 1C.
(1C does not mean 1 Coulomb, but 1 Capacity unit. This sometimes leads to confusion and frankly, I do not know why this unit was chosen.)

To sum it up:

For the white Eneloops (200mAh) recommended current ist btw 500 and 1000mA, max at 2000mA
for the black (XX) Eneloops (2500mAh) it is btw 500 and 1250mA, max at 2500mA.

Best results will be obtained with a modern electronically controlled fast charger that takes between 2 and 4 hours for a full charge cycle.
Very fast chargers (btw 1 and 2 hours) slightly reduce service life. If you accept having to buy new cells at a slightly higher rate, that should not be a problem, though.
For Eneloops especially, I would stay away from chargers that take less than an hour for a full charge (i.e. current more than 1C). They waste your cells and it would be wiser to just get a set of backup cells stored away readily charged.
Those chargers are from the days before low self discharging cells like Eneloop when you had to hastily top up your constantly discharging cells before you left the house. That is a thing from the past.

I agree totally with you that fast chargers will reduce recycle-life of AA cells, but the optimum recharging current is C/5 and not C/2 as you have stated above. All of my AA Sanyo Eneloops are rated at 1.2V 2000mAh, but take just 4 hours to fully recharge at 500mA. My charger goes higher, but I'd rather enjoy the full 1,500 cycles from these cells than say 700 to 800. It is better to just buy more of them than you actually need, thus keep spares (I have 36 AA Eneloops kept in neat 4-cell plastic containers) that fit any pocket in your DSLR bag.

What determines the optimum charging rate is resistance (Ohms) and unlike the Canon LP-E6 batteries (Battery = multiple Cells, so AA = 'Cell' and not 'Battery') which have quite low resistance, so can be charged faster using 1200mA standard charger, AA rechargeable cells have greater resistance, thus need longer to charge. Plus AA cells may be recharged from zero or near zero, whereas Li-Ion batteries perform better if they're topped up more frequently and is not advisable to let them go completely dead (laptops or DSLR batteries) as they may then stop accepting any charge whatsoever leading to quite costly replacement.

 

[JohnnyWashngo]

I use a technoline charger similar to this one...

http://www.amazon.co.uk/Technoline-Intelligent-battery-charger-Version/dp/B003S4JQS2/ref=sr_1_1?s=electronics&ie=UTF8&qid=1346681260&sr=1-1

... for charging my eneloops. I tend to charge them very slowly which usually means it takes several hours to fully recharge them. That charger is also really good for reawakening 'dead' batteries. I have managed to get a good deal of life out of older batteries that I thought were for the recycle bin.

I have ditched all my old fast chargers now due to them being generally rubbish

 

[SDsc0rch]

thx for such informative answers gentlemen

rienz.. This is the charger I use

http://www.amazon.com/Powerex-MH-C9000-PowerEx-WizardOne-Charger-Analyzer/dp/B000NLUSLM/ref=reg_hu-rd_add_1_dp

seems good to me - very full featured

 

[tron]

thx for such informative answers gentlemen

rienz.. This is the charger I use

http://www.amazon.com/Powerex-MH-C9000-PowerEx-WizardOne-Charger-Analyzer/dp/B000NLUSLM/ref=reg_hu-rd_add_1_dp

seems good to me - very full featured

+1 It is this charger with Eneloop batteries for me too.

 

[Jimbo]

Sorry for the use of the term batteries instead of cells, English ist not my native language and in colloquial German, the term Batterie is (incorrectly) being used for single cells as well.

About the recommended charging current:

C/5 might be the theoretically best current, but I have seen quite a few chargers who miss the -deltaV drop at these currents because it is too smooth, thereby overcharging cells.
Overcharging is a lot more damaging to NiMH cells than any good ultra quick charger on the market wold ever be. Only a deep discharge (possibly even followed by a reverse of polarity) is worse.

Also, most people, including myself do not charge cells often enough to really worry about reaching the maximum cycle number. If you recharge your cells 4 times a week, 1500 cycles would mean a 7 year service life.
Most people will recharge their cells a lot less often, thereby reaching a multitude of that so I just don't see the point.

Given that even Sanyo's data sheets state a 1C charge, I still believe a 1/2C or 1/3C charge can be done without worrying.

PS: NiMH cells and Li-Ion cells/batteries like the LP-E6 cannot be compared. Their totally different chemistry leads to fundamental differences in the charging process.

 

[tron]

I remember reading that the charging current for NiMh cells has to be over 1/2C (even by a little) for the chargers to stop charging correctly. I am sorry I am writing this by heart. I do not remember where I have read it (so please check for yourselves too).

 

[PeterJ]

I remember reading that the charging current for NiMh cells has to be over 1/2C (even by a little) for the chargers to stop charging correctly. I am sorry I am writing this by heart. I do not remember where I have read it (so please check for yourselves too).

I think it would most likely depend on the design of the charger rather than being a fixed limit, most better ones have a timer as well to terminate the charge and monitor changes in voltage rather than a fixed limit. However I've had this situation with a cordless phone charger, when the batteries died I replaced with ones about triple the capacity and the charge cycle wouldn't stop.