Can I replace my Alkaline AAA's with recharhgeable AAA's in 1.5v?

[fiberguy]

Yep, viper but I don't have it in front of me right now. If you want to, I can look it up though.

It does what you say and looks like a pager and that damn thing has some incredible reach

Yeah that's the one. Almost bought it. I've had my cars broken into so many times in the past 10 years. That's an awesome piece of electronic goodness. Kudos to you, you clearly have fine taste! :thumbsup:

 

[HKJ]

We're saying the same thing.

You do not need to pulse current for a correct -dv/dt charge termination.

 

[fyrstormer]

You do not need to pulse current for a correct -dv/dt charge termination.

You can't measure the output voltage of the battery while the battery is being fed input voltage. There might be ways to predict the output voltage of the battery based on the amount of input voltage necessary to maintain the specified charge rate, but I prefer the idea of measuring the output voltage of the battery instead.

In any event, we both agree that a smart charger is a charger that monitors the battery's state of charge, and stops charging when the battery is full, instead of just feeding the battery continuously until the user gets tired of waiting.

 

[HKJ]

You can't measure the output voltage of the battery while the battery is being fed input voltage.

With a constant current generator to charge, it is no problem to measure voltage and look for the -dv/dt.

 

[Lynx_Arc]

Explain the smart charger comment to me please

I want to measure them to see if they're ok

I was sending my mom some cordless phones and was gonna fill'em up with batteries
but I don't think I have to send away my eneloops as it seems I have others
to fill up the phones, but I still need to know what a AA and AAA ni-mh should
be at when charged to make sure it's good. I don't need her having problems

Thanks

Smart chargers monitor the charging process and detect when a cell is completely charged by preset algorithms. A good smart charger will not overcharge a battery unlike timer based ones. You can use a smart charger to recharge a partially discharged battery without overcharging it. On nicads overcharging was less of an issue but NIMH do not like being overcharged it can slowly deteriorate them costing you longevity and even result in high internal resistance and decreased capacity.

 

[Lynx_Arc]

I measured 1.7v on mine. A tenth of a volt is probably safe to write-off as being a statistical error between our voltmeters.

It typically is no issue till you start adding 4 or more batteries in series. When you reach 5 batteries a 0.3v difference makes it equal to an extra battery while it take about 7 batteries at 1.7v to equal an extra cell.

 

[guiri]

Yeah that's the one. Almost bought it. I've had my cars broken into so many times in the past 10 years. That's an awesome piece of electronic goodness. Kudos to you, you clearly have fine taste! :thumbsup:

Thank you sir. It's awesome when you're in the ELEVATOR, IN THE HOSPITAL and you remote start your truck that's out in the parking lot

Although I've never used it, when I had all this stuff installed, I also had a timer installed that could start up the truck when the cabin reached a certain temperature (high OR low).

Got it for the dogs but like I said, never used it. Cool that you can do that though.

Also, when I bought the alarm, they installed some blue, blinking led's on top of the dash for everyone to see
and I think that might also have helped keep people from breaking into the truck (touching wood right now)

Other than the occasional lightning and very loud vehicles setting the alarm off, I've never had anything happen so far.

 

[guiri]

Guys, I still don't know what a fully charged eneloop is supposed to measure and at what point I should throw them away/recycle them?

Thanks

 

[Lynx_Arc]

Guys, I still don't know what a fully charged eneloop is supposed to measure and at what point I should throw them away/recycle them?

Thanks

they measure about 1.4v off the charger and usually settle down to about 1.38v after a day. As for trying to figure out if they are good or bad you would have to figure out how much capacity they have to them and if that is acceptable or not. Many people toss or demote batteries at less than 80% original capacity.

 

[guiri]

Ok, so if they're fully charged and what voltage off the charger would be considered too low and should be discarded?

 

[Hondo]

You just can't figure that out by measuring voltage. They need to be cycled down at a known load. This will tell you how much capacity was in each cell. this is one of the primary functions that people buy the smart chargers for. Check into the 2 chargers I recommended above.

 

[guiri]

Well hell, I've got a maha and a lacrosse but not sure how to do that. I may have to see if I can find the manual for them.

I shall return...

Thanks

 

[Lynx_Arc]

Ok, so if they're fully charged and what voltage off the charger would be considered too low and should be discarded?

It doesn't work like that, most nimh even bad ones that do get charged will register a voltage within range. You can have cells that go dead in a short time because of high internal resistance and cells that have low capacity because of being worn out or damaged (cell reversal for example).

 

[Lynx_Arc]

Well hell, I've got a maha and a lacrosse but not sure how to do that. I may have to see if I can find the manual for them.

I shall return...

Thanks

I have a lacrosse bc-900 and I check cells that seem weak with it by doing a discharge refresh cycle on them, it discharges and charges the battery over and over till it reaches maximum. There is a test mode also that I think you can charge and discharge them to find capacity. You can also just charge a battery fully depleted and check how much mah current when into it when charge completes.

 

[guiri]

Well, I guess I have to find the manual for mine then. Damn, I can't believe I'm too stupid to even check my batteries

 

[Hondo]

http://www.google.com/url?sa=t&sour...rYCYCQ&usg=AFQjCNHnWe9AzKrJ-r1dUppCun8gn6Yulw

http://www.mahaenergy.com/download/mhc9000.pdf

 

[guiri]

THanks.

That's the lacrosse charger I have but the maha is different although I do have the manual so I'm good.

I take it I'm supposed to run them in REFRESH mode then?

Thanks

 

[Hondo]

For the LaCrosse, refresh will continue to cycle them up and down until they don't improve by more than a certain percentage. The test function will just charge them up, run them down to test the capacity they deliver, and recharge them. Same thing, just one cycle regardless of the results. Bottom line is either will work, and I usually start with the test function, since if the results are good, I don't really need any additional cycles, and if the results are bad, I can just switch to the refresh mode to see how good it can get them. The refresh function will do a minimum of two cycles, but sometimes for damaged cells can get them to much better capacity after a bunch of cycles.

I only have the C9000 Maha, and I can get a capacity by running a discharge on a charged cell (it won't recharge until I tell it to). It can cycle too, and I have to tell it how many cycles I want it to do.

 

[guiri]

I'll just test'em first then. Can I do four at one time?

Thanks

 

[Hondo]

Sure, no problem. Most would recommend a 500 mA charge for reliable termination. If you are not in a hurry, I have found that 200 mA works well for AAA batteries, at least on the LaCrosse chargers.