Uniden cordless phone battery life?

[Yzzim]

Originally posted by: Eli
Keeping a battery near 100% State of Charge without overcharging is paramount to longevity, whether it be NiCd, NiMH, lead acid or any other rechargeable battery.

Try not to let it get below 50% SoC and it should last longer than a year.

They're probably just covering their asses. I would say 1 year is the minimum amount of time the battery should last.

Even NiCd?? I thought they had the memory effect.

I use my cordless drill a lot and always wait until there is zero charge left before I plug it in. The battery has lasted me 3 years. Apparently I'm doing it wrong?

 

[Tiamat]

If you keep the phone on its charger, it should last longer. If you are one of those people who leave the phone lying around on the table at less than 80% (sometimes less than 5%) charge, it will fail in about a year.

 

[Red Squirrel]

Originally posted by: Eli

Originally posted by: Jeff7

Originally posted by: Rubycon
Pana-Sany now. :laugh:

Japanese cells > Chinese cells. SOME CN li-ions are actually pretty good but <danger!> they are naked, unprotected and the end user MUST have some kind of protection or they may face an eruption of hazardous materials, release of fire/flaming balls, and destruction of property. :Q

Mmmmm, I love battery talk.

Bwhaha!!!

Warnings from china are great. I have an inverter somewhere it says "Danger: This device is operating correctly. Please off switch system power before servicing" or something to that extent.

And we buy from those people.

 

[Old Hippie]

Warnings from china are great. I have an inverter somewhere it says "Danger: This device is operating correctly. Please off switch system power before servicing" or something to that extent.

The sad thing is, they probably had to put that there because somebody here already did it and sued! :laugh:

 

[Rubycon]

Originally posted by: Old Hippie

Warnings from china are great. I have an inverter somewhere it says "Danger: This device is operating correctly. Please off switch system power before servicing" or something to that extent.

The sad thing is, they probably had to put that there because somebody here already did it and sued! :laugh:

With a Chinese lawyer? If they win they'd get $1.0298. :laugh:

 

[0roo0roo]

nicad has lousy battery life.
but in some applications they can last way longer than nimhs. thousands of cycles.

 

[Jeff7]

Originally posted by: 0roo0roo
nicad has lousy battery life.
but in some applications they can last way longer than nimhs. thousands of cycles.

The strength of NiCads is their very low internal resistance, allowing them to provide extremely high current outputs.
Shorting them out can be a bad thing though.

Some NiMH cells also have fairly low internal resistance too, allowing them to be used in similar applications while holding roughly twice the capacity of a similar NiCad.



I wonder what the difference is between those cell types and nickel-hydrogen. I think that's what Hubble uses. One orbit takes about 90 minutes, so that's 45m of shade and 45m of light. Those batteries have been up there since 1990. That's way more than 100000 cycles on those things.

 

[Rubycon]

Originally posted by: Jeff7

The strength of NiCads is their very low internal resistance, allowing them to provide extremely high current outputs.
Shorting them out can be a bad thing though.

Gates Cyclon in BC size has 600 ampere SC rating! That will heat a 1/4 stud to red heat in quick order. Six in series (12V) will light off a double sharp pencil nice or braze two inch copper escape pipe with a carbon arc torch with power to spare. Unlike typical SLA and glass matt Pb they won't outgass excessive H under deep loads. Internal impedance is under 20 milliohms and that is key to cranking the amps out!

 

[Muse]

Originally posted by: Jeff7

Originally posted by: Muse
I read your post with skepticism, Spidey, but I have to think now that you may have hit the nail squarely on the head. This morning, less than 48 hours after finding this system, and about 36 hours after fully charging one of the handsets I found all three handsets completely discharged. :Q Their inability to hold a charge may well be the reason why the system was out on the sidewalk. Well, I'll keep them on the charging stands and see if I have problems (i.e. phone dieing in the middle of a conversation!). If I do, I guess I'll be in the market for replacement batteries. I hope not.

You charged them and then left the phones sitting off of their cradles?

If that's the case, I'm not too surprised. The handsets use power while sitting idle; some have displays which will use some electricity, and at the very least, they have to be listening for the Locate Handset signal from the base, should you wish to figure out where you left the darned thing sitting.

Is it possible that deltaV technology is built into some of these?

Possible, yes. I wouldn't know how to check though.

Yes, I left them off their cradles after charging them. Well, 2 showed full charge so I didn't charge them. I only charged the one that had no battery life showing. I figured they'd be OK out of the chargers for a day or two because I saw somewhere that the handsets support 7 day standby, which I take to mean they can sit off the cradle for 7 days before running out of juice. I was surprised to see all three belly up today after ~36 hours. Well, they've been on the chargers all day today (11 hours) and they seem OK, at least they're taking a charge. One is showing topped up now, can't see the other two right now. I set up the whole system this afternoon and things seem alright. Will see if I get cut off in a long conversation some day. Other than that, I figure it's fine.

As far as the deltaV thing, well, I forgot that the transformers (or whatever those new type wall warts are) aren't the only part of the charging system. They plug into a base unit, and that could have circuitry in it, some components, so maybe deltaV is supported in there. I could call Uniden's 800 number and ask a tech. At any rate, the charge rate seems very slow. I measured under 3 watts draw off the house wiring, so maybe the deltaV thing isn't so important in this. I think even sophisticated NiMH chargers supply some kind of trickle charge after the deltaV detection stops the regular charge cycle.

 

[Muse]

Originally posted by: Yzzim

Originally posted by: Eli
Keeping a battery near 100% State of Charge without overcharging is paramount to longevity, whether it be NiCd, NiMH, lead acid or any other rechargeable battery.

Try not to let it get below 50% SoC and it should last longer than a year.

They're probably just covering their asses. I would say 1 year is the minimum amount of time the battery should last.

Even NiCd?? I thought they had the memory effect.

I use my cordless drill a lot and always wait until there is zero charge left before I plug it in. The battery has lasted me 3 years. Apparently I'm doing it wrong?

I think they say to not let your NiCD drill get to zero. When it starts obviously losing power, stop right there and recharge the battery pack. Part of the reason for that is that there are multiple cells in there and if one goes to reverse polarity you could kill it.

NiCD memory issues have supposedly been addressed to some extent in recent years. It's not the issue it used to be. However, YMMV, who knows what you have there?

The fact seems to be that the more you use your NiCD cordless products the more use you will get out of them. If they just sit around for months at a time, the batteries will lose their capacity a lot faster than if you use them and recharge them frequently.

 

[Muse]

Originally posted by: Tiamat
If you keep the phone on its charger, it should last longer. If you are one of those people who leave the phone lying around on the table at less than 80% (sometimes less than 5%) charge, it will fail in about a year.

Mine's staying on the charger. I've had much better luck that way, but my experience is very limited of course.

OTOH, I leave my old Sonicare toothbrushes off the cradles until they start beeping and asking to be charged. I figure they have NiCDs in them and that they benefit from "full" discharges rather than leaving them on the cradles all the time. I may be totally wrong in that, dunno. I have to figure the manufacturer figured that a whole lot of people would leave them on the charge stand. The charger is very much a trickle affair, though, I measured the power consumption to be ~1 watt !! It charges by magnetic induction, pretty slick.

 

[Jeff7]

Originally posted by: Muse
As far as the deltaV thing, well, I forgot that the transformers (or whatever those new type wall warts are) aren't the only part of the charging system. They plug into a base unit, and that could have circuitry in it, some components, so maybe deltaV is supported in there. I could call Uniden's 800 number and ask a tech.

Good luck getting a "tech" who really knows anything about the product.


Concerning memory issues with NiCad batteries - I remember reading that some of that idea came up as a result of Hubble. It would discharge and charge to almost exactly the same levels, completing a cycle about every 90 minutes. With most consumer devices, you'll probably discharge to a different level each time.

Deep discharge though - definitely a bad thing.

If you're putting together a Li-ion pack, these controllers look like they'd be very nice - each cell gets individual attention from the charger so that they all have a reasonably equal state of charge.

Originally posted by: Yzzim
Even NiCd?? I thought they had the memory effect.

I use my cordless drill a lot and always wait until there is zero charge left before I plug it in. The battery has lasted me 3 years. Apparently I'm doing it wrong?

If you'd pop that battery pack open, the cells might have started to grow crystals on their ends due to leakage. I had a drill like that - the batteries were old, at least 10 years old. But the drill still worked.
The life was adequate, but not great. I decided to replace the NiCad cells with some NiMHs; the NiCads were getting kind of furry on their positive terminals.
I'd planned to replace the second battery pack's guts with li-ion cells which I'd salvaged from some laptop battery packs, but never really got around to it. (Yes, I have a protection circuit, and a charger that can charge li-ion packs.)

 

[Muse]

I've finally gotten the system set up to where I think it's going to work out for me. Medium size house and my concern was getting decent coverage where I need it. At first I had the base downstairs but that didn't work out. The manual suggests putting it up high so I tried the 2nd floor, and both locations there gave much better results. Right now I'm getting acceptable coverage everywhere. The manual also says to hold the handsets at the bottom, not the top and my experiments confirm that this gives much better results. I called my cell phone with a handset and walked all around describing where I was and later listened to my cell phone messages to determine how the system was operating.