
Most of the positive reviews here apply to the PS3 charger, not to the PS20/PS3D. I bought the latter, which is being sold here, thinking I was getting the former. I accept that I am responsible for not being more careful. This charger differs from the Rayovac PS3 in almost every significant way:
1. It has two independent channels, not 4.
2. It will not charge one battery in one channel, only 2 batteries in each channel. Need to recharge one battery or three? Tough luck. Your choices are zero, two or four (except for 9V batteries). The two battery slots in each channel are apparently linked in series, not in parallel, so each battery in a given channel gets the same current at all times.
3. It is only intended for use with NiMH batteries, not NiCd or rechargeable alkaline batteries.
4. It is not remotely smart. It makes no effort to determine battery type or if batteries are fully charged. It puts out a constant current at 2.8V and never stops. (This voltage is specified on the back of the charged and is what makes me thing that the two batteries in each cell are linked in series.) It is up to you to guess when the pair of batteries is fully charged and pull them out then. Also, if you're putting a charged battery in with a discharged one in order to charge an odd number of discharged batteries, they both get the same treatment. The only thing that varies is that larger batteries get higher currents (D=560mA, C=440mA, AA=260mA, AAA=120mA, 9V=14mA).
5. It charges four AA or AAA batteries at a time, not eight.
6. The status indicator tells you nothing very helpful. It turns on when you have two batteries in a cell and never turns off.
Avoid this charger. The only advantage I can think of for it is that, like other completely dumb chargers, it will charge batteries that other chargers reject as dead. Sometimes such batteries are just completely discharged and work well after being charged by a dumb charger like this one.

[IMPORTANT NOTICE on Jan 1, 2010]:
I've been informed (thanks to Domenico Perrella) that the item being shipped now is the 'PS3D', which is an inferior product compared to the 'PS3' described in my original review. If you have ordered the PS3 but received the PS3D instead, return it to Amazon for a full refund on the ground that the product description does not match the product received.
[Original Review follows]
I already have at least half a dozen smart chargers in the house, including top-of-the-line models such as the La Crosse BC-900 and Maha C9000, but I still wanted this Rayovac Universal Battery Charger (PS3) for the following reasons:
1. It can accept C, D, and 9V batteries in additional to the standard AA and AAA cells.
2. It can handle rechargeable alkaline cells in addition to the standard NiMH or NiCd cells.
3. It has the potential to recharge up to 8 AA or AAA cells at once.
So far, I'm very satisfied with this charger. Of course it is bulky and heavy. But that's to be expected for an unit that can accept four D-cells at the same time. For home use the size and weight is not an issue at all.
I'm happy to report that this charger is a lot smarter than I previously imagined. Unlike a typical dumb charger in this price range (for example: the Energizer CHFCV Overnight Family Charger), the PS3 has four independent charging channels. That means I am free to charge different cell in any channel. Each channel comes with a status indicator LED, which goes out once the cell is fully charged. But most of all, this charger is smart enough to recognize the difference between NiMH cells and alkaline cell, and can pick the correct charging method accordingly.
When an unknown cell is inserted into the PS3, the charger first starts off with a trickle current (800mA peak current at 10% duty cycle, or an average current of 80mA). Based on the voltage profile of this cell, the PS3 can determine whether this is an alkaline cell, or a NiMH cell. After two minutes, the duty cycle is increased to 60%, so the average current is now around 480mA. For a NiMH cell, charging will continue until a negative dV/dt is detected, in which case it switches back to trickle current again. But for an alkaline cell, charging current will gradually decrease with higher terminal voltage until it reached 1.65V.
The Rayovac PS3 is designed to recharge the Rayovac 'Renewal' brand of rechargeable alkaline cells (which are now discontinued). The user manual warned against charging ordinary disposable alkaline cells, but I experimented with it anyway. So far, I have observed very good results with recharging Duracell alkaline AA cells [see warning below]. Of course, the capacity of a recharged alkaline cell is lower than that of a fresh cell, and it drops with each subsequent cycle. But since I can squeeze another half a dozen cycles out of an exhausted alkaline cell at no additional cost, I really should not complain.
Back to the charger itself, I do have a complaint about its claim of "recharge up to 8 AA or AAA batteries". It turns out that each of the four charging channels can accept one to two AA or AAA cells, but the two cells are electrically connected in parallel. So in case somebody accidentally placed two cells of different battery chemistries (NiCd, NiMH, or alkaline) in the same channel, the one with lower voltage will discharge the other one. The charger may also get confused and fail to terminate correctly in such case. It is safer and faster to charge only one AA or AAA cells in each channel.
[WARNINGS:]
1. Do NOT try to recharge alkaline cells that are completely exhausted (terminal voltage below 1V). It will not work.
2. Do NOT try to recharge Energizer alkaline cells. Four Energizer AA cells I tested completely dropped dead after just two discharge/charge cycles. Two D-cells started leaking electrolyte a few days after charging. Luckily they were left outside and not being used.
[Update on Jan 26, 2009]
Out of maybe one dozen Duracell AA alkaline cells I have recharged, two started leaking electrolyte a few weeks later. I must now officially advise AGAINST recharging disposable alkaline cells: do it at your own risk!
Buy Rayovac PS3D Universal Battery Charger for AA, AAA, 9V, C and D Rechargeable Batteries Now
The battery charger was packed well and received quickly.
The charger is great because it accommodates all the usual suspects (AAA/AA/C/D size batteries). Most chargers I've seen only charge the AAA/AA batteries.
The only thing I would change... it takes so long to charge a set of batteries... couldn't it be a little faster???
However, this is great to use on baby toys (as well as your big kid toys)... just buy an extra set of batteries so you can always have a set charging while the other is in the toy.
The only reason I mention that is because the batteries do run down kind of quickly, and take up to 8 hours to fully charge.
But I'm not complaining... while there is an initial investment, think of the money you'll save on buying new batteries all the time. And you'll be doing a small part for the environment by not throwing out batteries all the time.
Read Best Reviews of Rayovac PS3D Universal Battery Charger for AA, AAA, 9V, C and D Rechargeable Batteries Here
Recharges all 3 kinds of batteries:
alkaline, NiMH, NiCad. Recognizes the battery kind automatically.
Accepts all "1.5" volt battteries, AA, AAA, C, D.
Batteries are found in every electronics and department store:
WallMart, Kmart, Circuit City, Eckerd, Walgreens, Target, BestBuy etc.
The only bad news: 110 V only. It would be nice to have this toy in a 100-240 V AC auto mode.
Want Rayovac PS3D Universal Battery Charger for AA, AAA, 9V, C and D Rechargeable Batteries Discount?
This review is for the Ray O VAC model PS20/PS3D battery rechargerRayovac PS3D UNIVERSAL CHARGER,.
1) This model recharges ONLY NiMH rechargeables. It does NOT recharge alkaline or NiCad rechargeable batteries.
2) This charge does NOT tell you if a battery is bad.
3) This charger does NOT tell you when a battery is finished recharging.
4) This charger takes about 12 hours to recharge a battery.
I know that this model does recharge NiMH rechargeables of the following sizes: AAA, AA, 9 volt. It likely also recharges C and D rechargeable NiMH batteries, as claimed, although I haven't tried it.
Several of the reviews here claim that the model PS3 will recharge NiCad and alkaline rechargeables, as well as NiMH rechargeables. That may be true for the PS3, but is NOT true for the PS3D.