Whether or not the consensus view on this issue is correct, replacing rechargeable batteries with non-OEM devices is NOT something someone with little understanding of rechargeable batteries should do. I would simply buy the iRobot batteries and forget about it.
The basic problem is that manufacturers often charge too much for replacement batteries. If the battery pack is used in current models (no pun intended), it shouldn't be expensive.
Ut Oh! How dare you correct the almighty Phil Allison!
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Dear P.O.S. Bill Phil is totally right about you. Furthermore your always out there pushing your luck looking for some Internet nut to one day make your day. Bill you trolling P.O.S. I hope you run right into the arms of your Karmatic fate. I too am keeping and eye on you waiting to see what happens to you.Yea I am the fellow, a victim of one of your stupid sick jokes. While I am out here trying to make a buck so I can slide food across the table to my hunger family you are cracking on my wares. Well Bill F*CK you, you P.O.S. stupid troll. You are definitely the pitiful excuse for a human being. Good luck on your search, hope you secede Bill and get what you deserve.
Dear P.O.S. Bill Phil is totally right about you. Furthermore your always out there pushing your luck looking for some Internet nut to one day make your day. Bill you trolling P.O.S. I hope you run right into the arms of your Karmatic fate. I too am keeping and eye on you waiting to see what happens to you.Yea I am the fellow, a victim of one of your stupid sick jokes. While I am out here trying to make a buck so I can slide food across the table to my hunger family you are cracking on my wares. Well Bill F*CK you, you P.O.S. stupid troll. You are definitely the pitiful excuse for a human being. Good luck on your search, hope you secede Bill and get what you deserve.
The person who wrote is still objecting to a joke I made some time back about his rebuilt CRTs, which related to the "going all the way to 11" joke in "This is Spinal Tap".
His attitude suggests that anything he disagrees with or doesn't understand is some sort of a personal attack.
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Dear P.O.S. Bill As usual you Trolling P.O.S. you got it all wrong and misrepresented everything. The CRT as you fully remember was OEM not a cheap Rebuilt Furthermore you do not even know me to make such a Quantum leap judgment about me. Just another example in a long list of examples how you readily talk about things as the consummate expert when in reality you are completely clueless, a idiot's imbecile. As far as Jokes I could call you the butt of the Joke but you probably like that so I will not. .
On 2/21/2010 1:41 PM ancient-time-traveler spake thus:
[...][blah blah blah snipped]
Hey, Mr. Trollface: Nobody gives a *S*IT* about the ancient history of your old arguments. Nobody. Please just give it up.
I'd also stay indoors if I were you...
Assuming someone has reasonable DIY skills and sticks to tagged replacement cells of the same type as the originals there's little to worry about. It's certainly not any more hazardous than many common tasks people take on.
"William Sommerwerck" wrote in news:hlrin9$iic$ snipped-for-privacy@news.eternal-september.org:
Manufacturers don't want to sell replacement parts. Also,replacement parts are handled differently than manufacturing stock,they get inventoried and taxed,and those costs get added to the part price.
a realistic alternative is to go to a rebuilder and have them make you a new pack from new cells.(of the same type/chemistry as OEM.)
Sorta. Most NiCd chargers use the voltage drop at the end of charge. NiMH batteries do have a similar voltage drop at EOC, but it's far less obvious or easy to detect. NiMH chargers tend to use temperature and either the a zero slope (no rise in voltage), or a negative voltage drop. Since the temperature peak ocurrs AFTER the negative slope, there's a really good chance that using a temp sensor will cause overcharging.
This might explain it better:
I would still be cautious. For one thing, you want to be sure the replacement cells have at least the same capacity as the originals. Higher is probably okay, lower is almost certainly not.
If a battery dealer can make up a pack for you, it might be a good idea to take the old pack in and have them do it. However...
My experience with non-OEM Li-ion cells has been that, even when they come from a recognized manufacturer, they quickly deteriorate. They're a complete waste of money. Nicads and NiMH cells aren't so critical, but there is the possibility that the charger for the product might have been designed for a particular battery from a particular company, and might not work correctly with other batteries.
Just to dump on Mr. Allison again... I've replaced the nicads in several Polaroid #365 electronic flashes with MAHA 2200mAH tabbed NiMH cells. The original cells were designed for rapid charge, and the charger is supposed to fully recharge them in one hour. The charger works fine with the NiMH cells, and shuts off properly (even though it's probably not at would be full charge for those cells).
True, but they are legally obliged to. Unfortunately, there doesn't seem to be much enforcement of the laws.
True, but... That doesn't change the fact some companies -- such as Thomson -- GOUGE. Please tell me how two AAA NiMH cells with a little cable and socket can sell for almost $25. And this is a current-production battery.
You mean most /rapid-charge/ nicad chargers use the voltage drop. If you're charging at 0.1C, you don't usually need to terminate the charge. And if you use just a resistor to set that charge rate at 1.0V, the current will drop to below 0.1C at the end of charge.
I've charged NiMH cells in conventional non-rapid-charge nicad chargers. It works fine.
The harder the cell is charged, the greater the drop. Microsoft used a hard charge which produced an easily measured drop.
I'm not sure all the information at this site is correct. The statement that voltage drop should not be used is questionable. The Microsoft charger used both delta V and either T or delta T (I don't remember) to terminate charge.
"William Sommerwerck" wrote in news:hlsmi1$ik0$ snipped-for-privacy@news.eternal-september.org:
A company(Fortune 500 at the time) I used to work for would raise their parts prices as the product that the parts went into got closer to the end of support period. I was told this was to "encourage" customers to buy a newer instrument,by raising the cost of repairs.
It didn't matter that the parts were "in current production".
"William Sommerwerck" wrote in news:hlsn2u$n0p$ snipped-for-privacy@news.eternal-september.org:
Yes,those slow chargers don't have any sort of charge sensing. they're just transformers,rectifier and current limit resistor,if the XFMR doesn't limit on it's own. So,you have no idea of charge time,it's just a guess.
IMO,rechargeables last much longer with a fast charger.
Hardly surprising. I could tell you some stories about my dealings with Sony, but I won't. Suffice it to say that I made friends with the parts honcha, who was occasionally able to help me a bit. Though her job was eliminated, we still talk occasionally.
In "encouraging" customers to buy new products -- rather than repairing the old -- businesses contribute to waste and pollution.
That might be true. One of the non-professional Web reviews of NiMH chargers revealed that there was significant difference among them in how much they heated the cell.
I'd hope not. A proper slow charger works at constant current.
Not my experience at all. I used a slow charger with a timer for most - and usually got the stated number of cycles before failure. Although this was mainly with Ni-Cads which were discharged to the point where the performance dropped off.
Like this puppy, with selectable constant-current rates:
I also like it because it charges individual cells, not pairs.
My understanding is that NiMH cells do exhibit a voltage drop after they're fully charged, just as NiCd cells do. However, with NiMH cells you don't see an appreciable drop in voltage until after the cells have already gone into over-charge... and NiMH cells really don't like being overcharged. If you charge until the voltage drops, you're likely to overstress the cells and seriously shorten their life.
If you're going to use a voltage-based shutoff with NiMH cells, I understand it's better to use an earlier-cutoff technique - one which "notices" that the cell voltage has ceased to rise with time (a "zero delta V" detect, rather than a "negative delta V").
The good NiMH fast-chargers I've seen, seem to use a three-level strategy for charge shutoff:
- Temperature sensing, T or delta T (primary)
- Zero delta V (secondary)
- Timer (failsafe tertiary)
The first two tend to work better with a relatively fast charge rate, as the temperature rise and voltage inflections are more easily detectable.
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