very confuse could need come help

[Scotch]

Hello,

I am new to this forum, there is a lot of information. But the more I search and read the more confuse I get. I need some help sorting things out.

Battery:
Take the Battery University.com for example. It has a do and don't battery table. Using in, charging, discharging, service needs, storage, etc. It is clear, simple, concise, It sounds great. Can I follow those recommendations specially for NiCd and NiMH batteries?


Charger
Back in 2004, Dave Etchells of Imaging Resource review the Maha/PoweEx C-204W. He said it was his new favorite charger for NiMH and use it for is batteries review. So I bought one and was very happy with it.

Recently I read that single channel charging is better then dual channel. So now the C-204W is no good anymore?

Now I have those solar lamp and they use NiCa so I need a charger and read about Silverfox review of the C401FS. Ovoid the fast charging mode because the batteries become very hot. The slow charging mode is better. So I bought one. Then I read some post saying that the slow charging mode is to slow for the batteries. Can anybody clear this up?

The C401FS has a FLEX Pulse that makes traditional "battery conditioning & cycling" unnecessary as the pulse eliminates the memory effect just by charging the batteries. Could that be true?

I just got those new solar lamps with automatic shot down after 6 hours. I just found out they use lithium Phosphate batteries. This time of year not enough sun to charge them any idea where I can find a charger for these?

Thank you
Scotch

 

[Mr Happy]

Wow, what a lot of good questions!

:welcome:

Unfortunately, the answer to many questions like these is not a simple yes or no, but more often "it depends".

The C-204W is not a bad charger, but in some cases it is not the best choice.

The C-401FS might be fine in the fast mode, but it depends on the batteries. If you find the batteries getting too hot, try the slow mode.

The slow mode might be fine too, but if you find the batteries don't finish charging at the expected time and over run, then try the fast mode.

The FLEX pulse method may work, however I have no experience of it and do not know.

It will be hard to find a simple and cheap charger for the lithium phosphate cells. They seem to be a new introduction and specially formulated for use in solar lights. There are chargers available for lithium iron phosphate cells in general, but they tend to be specialist items and a bit expensive.

I'm sure now you are more confused than before

However, stick around and with a few more answers in this thread and a bit of reading and absorbing you will get a better picture.

 

[Scotch]

Mr Happy,

Thank you for answering,

I really like your piece on ''Charging NiMH at high and low rates -- what can go wrong'' .

Should I follow Battery University guide lines for NiCd and NiMH batteries or do you feel it is in the ''it depends'' category?:candle:


Thank you
Scotch

 

[45/70]

Should I follow Battery University guide lines for NiCd and NiMH batteries or do you feel it is in the ''it depends'' category?:candle:

Battery University is pretty much gospel around here, so I consider it a good source of information.

[FONT=Verdana, Arial, Helvetica, sans-serif]Isidor Buchmann is with Cadex. They are a manufacturer[/FONT] of battery analyzers and chargers. They do not sell batteries. It is in their own best interest to provide information that is accurate as to how to properly care for their customers batteries. So, consider the source.

Dave

 

[Scotch]

Thank you 45/70,


How do you dertemine your NiCd or NiMh batteries are at 40% before storing them?


Thank you
Scotch

 

[Databyter]

One of the main differences with different chargers is how they sense a full charge for a particular battery chemistry (or if they do).

I have for instance a "dumb" dual battery charger that I got with my camera that actually uses a circuit timer to charge the battery and turn off at a given time. It's considered dumb because it doesn't consider brand or capacity but relies on "rule of thumb" averages.

Since I recieved several packs with my camera this is a fine charger for the purpose and I use it, but I would not use it to charge say individual batteries singly that I would later put in a pack, or that were super high capacity, or designed for the upper end of current capabilities. I could, but it would in some cases undercharge the batteries, and in other cases possibly over-charge them without sensing it.

Another problem with some dual chargers is that dumb or smart they frequently turn off both batteries when the magic moment is reached, even if one is not quite max.

If you use a wide variety of rechargables for a wide variety of situations it's best to have some sort of an individual cell sensing smart charger, or a smart pack charger that will charge all the cells (for a specific application and that are only used togather) together.

This is the solution I use for anything that takes over 6-8 cells, I still use my two cell dumb chargers for less intense applications that use more run of the mill batteries. But for most applications I get batt. holders from radio shack (a few bucks each) and hook up my voltage flexible smart charger to the holder and charge them all at once.

As someone said above it really depends on what your doing. For most applications a "dumb" two cell charger while not ideal is 95% fine, which is good enough in the real world.

 

[Benson]

It will be hard to find a simple and cheap charger for the lithium phosphate cells. They seem to be a new introduction and specially formulated for use in solar lights. There are chargers available for lithium iron phosphate cells in general, but they tend to be specialist items and a bit expensive.

The "normal" recommendation for LiFe cells seems to be the WF-139 charger, and it's not all that expensive. Unfortunately, it's designed for CR123A-sized cells, so some sort of mod or jury-rigged battery holder is needed to deal with the 14500 (AA-size) cells used in solar lights.

As far as being specially formulated, though, AFAICT, they're not really. I bought some at Walmart, and they charge fine on my WF-139, have similar voltage ranges when full/empty/under load as other LiFePO4s are supposed to have; internal resistance is significantly less than 14500s and CR123 primaries I tested. And the capacity penalty (400 mAh in 14500) is similar to LiFe RCR123s. Maybe there is a difference, but I'm not seeing it in my (admittedly rather limited) testing and usage.

From what experience I have with them, I'd say treat them like any other normal (i.e., not super-high-current A123) LiFePO4 cells.

 

[45/70]

How do you dertemine your NiCd or NiMh batteries are at 40% before storing them?

With NiMH/NiCd cells, you pretty much have to guess where 40% is, from experience. There are several testers that you can obtain a 40% reading from, but none of them are very accurate. Different manufacturer's cells have different voltages at the 40% level, as do cells of varying degrees of use and age, so you can't really use voltage as a gauge.

That said, what I do when storing cells that are not going to be used for a while, is store them at ~1.25 Volts OC. I check them once in a while, if they don't get used, and charge them up to 1.25 Volts again, if their voltage drops below 1.20 Volts.

Dave

 

[TakeTheActive]

...How do you dertemine your NiCd or NiMh batteries are at 40% before storing them?

1. DISCHARGE them @ 0.2C to 0.9VDC on a Maha MH-C9000 or La Crosse BC-700/BC-900/BC-9009.
   .
2. CHARGE them until xx% mAh go back in. (i.e. ~500mAh for a 2000mAh AA Eneloop for ~25%)

BTW, why did you pick 40%? IIRC, SilverFox recommends 25% for NiCD/NiMH. CLICK on my Sig Line LINK - it's in there.

40% is the 'Magic Number' I use for (my *only*) Li-Ions (the cells in my cellular phones).

BTW, just for future reference, those 1.2-1.5VDC AAA/AA/C/D 'thingies' are CELLS, not BATTERIES. A BATTERY is a group of CELLS, like the rectangular 9VDC of 'Transistor Radio' fame and the 12VDC Lead Acid used in automobiles.

 

[Scotch]

Guys,

Thank you for the information,

TakeTheActive: If you recall at the beginning of my post. I ask about Battery University: Do and don't battery table. That is where I got the recommendation for the 40%.

As for the cells well when I read to: ''run the battery fully down once per month or Do not leave battery in charger for more than 2 days because of memory and Avoid getting battery too hot during charge.'' I was under the impression they where talking about those ''1.2-1.5VDC AAA/AA/C/D 'thingies' '' Thanks for the information:thumbsup:

Scotch