What voltage should eneloops have straight off the charger ?

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Boaz
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What voltage should eneloops have straight off the charger ?

 my new batteries were pretty dang hot and the charger hadn't shut down after maybe 5 hours  so I pulled them .. they were 1.45 volts and toasty . it's a lil handy rayovac charger that charges  at 2- 2.8 volts  350mh for AA  (i assume that means it needs 2 batteries at least to charge  on side      ////  and 150 MH for AAA.

 

I've heard people say that batteries only get hot at the end of their charge .

 

these are new duraloops and I didn't use them first or even check voltage I just tossed them on a charger ..Do you think i should have  used them before charging them ??

 

the charger stayed red and never hit green but at 1.45 i pulled them .. figuring they were done .. BUT what is the normal voltage of your eneloops fully charged  if you have them

 

this is the charger >  http://www.google.com/products/catalog?q=ps+32+rayovac&hl=en&rls=com.microsoft:en-us:IE-SearchBox&rlz=1I7RNWN_en&prmd=ivns&resnum=11&um=1&ie=UTF-8&cid=13130023631969381977&ei=YSZFTe_vNcrTgQem8MGJAg&sa=X&oi=product_catalog_result&ct=result&resnum=1&ved=0CFIQ8wIwAA#

maybe I just jumped the gun .. they weren't on there for over 8 hrs.

I just don't like heat

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Edited by: Boaz on 01/30/2011 - 03:56
fran82
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If I am not wrong, NiMh cells are 100% charged at 1,40 volts. However can be charged up to 1,5 or 1,6 volts, but battery life is drastically reduced

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Boaz
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What kind of voltages do you normally see on nimh hot off the charger ?

I had an older charger that i had some 1200mah(old dark green White topped really tuff cells ) AA's  that topped  over 1.55+.. but i wasn't worried since they were old . like 14 years ??

 

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Budgeteer
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I do see 1,46-1,47 on sanyo specimens... never took the effort to look at others. Capacity was more of an issue for me.

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Don
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I've just stuck 8 on charge to see. They have been charged recently (All of them around 1.35V)so it shouldn't take long. The first four cells have seen a lot more use than the second four. These are the voltages immediately after the charger terminates the charge and will drop as the cells stand. I'll measure the voltages again in a couple of hours to see what they drop to on standing. The chargers are saying that all 8 cells are over 1.5V. But that is while current is being stuffed into the cells so the "real" voltage of the cell will be lower.

CellVoltage
11.531
21.531
31.513
41.518
51.520
61.505
71.501
81.501

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

Boaz
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One reason i ask is because I have some eveready AA's and AAA's ,,don't think I've seen much over 1.409 or so ..  the AAA's at maybe even 1.389  or just shy of  1.4 ..

 

 i hadn't really paid attention because it was older stuff i had laying around

what about mixing same types but 2100 mah with 2300?/ i have been doing ..again because i really didn't care  about the cells  and wasn't mixing chemistries .. just capacities ... if they were hugely differentI tried to group them together ...BUT what does anyone think about charging a 2700 paired with a 1200..is it just roasting the 1200?

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Boaz
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All 4 of mine have cooled down and dropped from

1.450 to 1.440

1.450 to 1.440

1.445 to 1.435

1.445 to 1.435

 which makes sense because of the different sides of a cheap charger

**Again these are brand new out of the package too so they might act stupid for a few charge/ discharges

 

Ok a few more stupid battery questions while  we are  at it ..

1.# when is a nimh battery empty in your opinion ..i know it depends on the light or device it's used in .. but generally  what's the voltage where you say ,,, ha ! .. into the charger you go .?

2.# same question maybe more importantly  for an 18650  or 14500 etc ..

3.# i got 4 out of 5 packs of white top duraloops ..1 -4 pack blacktop made in china .. how much should i really care ?..Percentage wise how much worse are ..Dura birds? is that what they are ?

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Don
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In a charger with individual channels this will be fine - if you need to put cells into the charger in pairs, don't mix capacities.

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

Don
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Around 1 volt is empty for an NiMH

I try not to get my lithium ion cells below 3V. They should definitely not go below 2.8V

Don't know about the Duraloops - they aren't very common here.

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

Boaz
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Duraloop is just  what they call a duracell  pre-charged LSD nimh battery.Proctor and Gamble who bought Duracell  are rebadging eneloops with their name on them instead of building a LSd battery themselves  .. the up side is they are  real eneloops, they are fresh  and 42% cheaper than eneloops ,).plus  .. they aren't ever gonna be chinese  "fake a loops "...

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Don
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After standing for an hour

CellVoltage
11.467
21.467
31.458
41.460
51.462
61.452
71.446
81.447

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

phlowcus
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While we're at it, what kind of voltage drop is to be expected with proper lsd cells after 2/3/4 weeks? My freshly charged recykos went down to 1,37 in only 10 days, is that normal?
sixty545
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Boaz wrote:

 my new batteries were pretty dang hot and the charger hadn't shut down after maybe 5 hours  so I pulled them .. they were 1.45 volts and toasty . it's a lil handy rayovac charger that charges  at 2- 2.8 volts  350mh for AA  (i assume that means it needs 2 batteries at least to charge  on side      ////  and 150 MH for AAA.

 

I've heard people say that batteries only get hot at the end of their charge .

 

these are new duraloops and I didn't use them first or even check voltage I just tossed them on a charger ..Do you think i should have  used them before charging them ??

Yes, absolutely. You should have used them first.

NiMh batteries that have been unused for a long time (like new batteries) often don't provide adequate voltage drop (-delta V) to the charger to signal end of charge. If the charger has no timer or heat detection stop to save the batteries, it will cook the batteries until you pull them. This is worse for low charge currents than for higher.

You can remedy this in two ways (from an article and also my own experience):

1. If the battery is charged, you start using it and then charge it.

2. If the battery is low on charge you charge it for half the normal time and then use it.

You can use 2. after using 1. to be sure with new batteries.

 

This is the curse of -deltaV charging. I much prefer Zero deltaV charging for NiMh but you have to build your own intelligent charger.

 

Good charging!

Don
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phlowcus wrote:
While we're at it, what kind of voltage drop is to be expected with proper lsd cells after 2/3/4 weeks? My freshly charged recykos went down to 1,37 in only 10 days, is that normal?

 

Sounds about right to me. Mine are around 1.33V but it is several weeks since I last charged them.

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

Boaz
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(-delta V)  so that's what they call that  bounce ..a negative delta V....huh .. I knew that the voltage would climb and then bounce backwards ..down >  sending the signal to the charger to shut itself off . I knew it about lithium battery charging .. have no idea why I would asssume nimh would be any different .. mmmm -delta V ... big  words to impress women with ..

The easy answer is this ...whee!!!Smile i got new batteries

1.427

1.427

1.420

the last one got installed it's time to work him out . i may just work these 4 out over the next week or so and keep track of the numbers just for fun...

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sixty545
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I think I gave you a simple advice concerning the charging of unused cells.

There is nothing fancy about -deltaV. I think you have some reading to do about the basics of charging Wink .

Try this to start with.

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Using my Varta charger (full charge):

Varta R2U, 2100 mAh - 1,47 V

GP Recyko+ 2100 mAh - 1,44 V

Old GP 1300 mAh - 1,42-1,43 V

2 weeks later:

GP Recyko+ 2100 mAh - 1,36 V

Old GP 1300 mAh - 1,30-1,31 V

3 weeks later:

Varta R2U, 2100 mAh - 1,36 V