should i buy Energizer CHVCWB2 Overnight NiMH AA reviews

The light comes on when it's charging, but never goes off, so you never know when it's done. Also, you have to charge 2 or 4 at a time, not one or three. Seems to work OK. It is not clear enough from the earlier reviews -- This charger DOES NOT automatically shut off when the batteries reach full charge. It just keeps cooking them, and they do get quite hot. Can't be very good for them....

I don't have this specific model of charger (I have CHVCM with the same green lights), but I want to give some input on overcharging. It is only safe to leave NiMH batteries charging indefinitely if the charging current is less than 10% of the cell's current rating (The mAh rating.) If the charging current is higher, then you definitely do not want to leave the batteries charging past full charge.

To calculate the charging time, just divide the battery's mAh rating by the charging current output by the charger (measured in mA.) I couldn't find a spec sheet on this charger, so you'll have to flip it over and look at the writing on the back or sides. It will be around the other electrical specifications (AC input voltage and DC output voltage ratings.)

My charger lists the charging current as: 260 to 300mA (~15% of cell's rating). So with 2000mAh batteries, that's an average charging time of about 7 hours. Of course, chargers and batteries vary, so I would let it run a little longer. (My spec sheet reads 8.5hrs for 2000mAh and 10.5hrs for 2450mAh. It also says that there is an 11 hour shutoff timer. Nice!)

You don't need to be totally paranoid about how long you let the charge go, but it does need your attention. Going by the math above, I don't think you'd run into any trouble if you let the charge run for 10 hours, but I would be nervous to let it run for 15 hours. If you want to let it run overnight, but are worried of charging too long, just use a simple AC lamp timer to decide how long to run the charge while you're sleeping. You can pick one up for $10 or less.

That being said, you may be able to charge the suckers for 24 hours without starting a fire or causing the batteries to explode (but maybe not), but it would definitely hurt the battery's ability to hold a charge.

I guess I didnt read well, it does not tell me when they are done charging which makes it little dangerous. but it works This is a charger which (A) requires you to remove the batteries after a specified time interval and (B) only charges in pairs. This wouldn't have been a disappointment in the late 1990s but, these days, it seems silly for the user or the batteries to suffer needlessly. Why not just purchase a decent charger? I certainly regret purchasing this one...I'm pretty sure my old charger is just an older design of the "basic" charger and I absolutely loved it, but it gave up on me recently so I had to buy a new one. This one is flawed in design. There is barely enough depth to grip the batteries, and then they are facing at a downward angle from the wall, so their weight basically pulls the charger off the wall immediately. I wish I had read the reviews here first. I will be purchasing a different Energizer charger when I return this one, as I do like the brand. I just wouldn't recommend buying this one.

Update - changed my rating because we eventually figured out how to get it to stay in the wall. I still think it could grip the wall and the batteries better, but it's at least doing its job now. I also left feedback for Energizer on their site and received a response right away, so kudos to them for trying to take care of their customer. (I declined their warranty offer, since we had managed to make it work). A 'smart' charger monitors each battery's status individually, and stops charging when each battery is full. This is the only way to ensure that your batteries are fully charged but not over-charged.

A 'dumb' charger typically charges batteries in pairs only, and relies on a safety timer to terminate charging after 8-12 hours.

This Energizer CHVC3 Overnight charger (also called 'Basic Charger') shown here is dumber than dumb. It has no charge termination mechanism at all. It simply charges each pair of batteries at a low current (190mA for AA, 90mA for AAA) FOREVER. It is up to you to remember to remove the batteries after certain number of hours, as estimated by:
[ Charge Time (hour) = Capacity (mAh) / Current (mA) ]

For example, if your batteries' capacity is 2000mAh _and_ they are completely discharged, then it takes roughly 11 hours to fully recharge them (2000/190 = ~11 hours). But if the capacity is lower _or_ they are only partially discharged, then the required charge time is shorter.

NiMH batteries can typically withstand over-charging at 0.1C current (which means 200mA for a 2000mAh cell) without immediate damage. So if you forgot and left your batteries in this charger for an extra day, they are not going to leak or explode. But in the long run, over-charger will lead to reduced capacity and shorter lifespan.

Instead of this primitive Energizer Basic Charger, you should consider a better product such as the. The Sony charger is smarter, faster, and takes better care of your batteries. It will save you time and money in the long run. This isn't horrible but it's far from great.....or even good. This product does recharge but the indicator lights do not turn off. If you read the other reviews then you might have noticed this pattern. Since the lights do not turn off be careful not to over charge and get the batteries too hot. Not knowing when the battery is 100% means you just have to play the guessing game. 24 hour charge should do. I recommend forking up the extra two dollars and getting their better model, which I give a good four stars. The lights work and everything. Try to avoid this. You've been warned. I've had this charger set for about a year, and the only thing I've used it for is my digital camera. I use my camera less than the average person, but I use it even less now that this is my source of power for it. The batteries never held charge for very long (not time for me to take more than about 5 pictures)--I'm assuming that's because as other reviewers have said, the batteries get overcharged with this charger. After maybe one or two uses a month, my batteries don't hold any charge. Worthless product! What a waste of money. left on charge overnight, i thought my house was gonna burn down with the heat generated from this crappy charger.
Lights come on but never turn off so its impossible to know when they are at full charge ( if they ever reach full charge).
Battery life is woefully low, i used it for my Radio Controlled racing car and got about 3 mins of constant use then, zip ! batterys flat dead. charged them again overnight. woke up, same deal. batterys scorching hot to the touch and 3 or so minutes use in my RC car before dying out completley.
This charger now rests comfortably in the bottom of my garbage bin, awaiting for the bin man to come and take it where it belongs, in a land fill.
kept the actual batterys that came with it and now charge them in my brand new Duracell charger, works like a charm.
very surprised and disapointed with Energizer ??? WTFI'm surprised that a major brand like Energizer made such an extremely poor product. You can leave your batteries charging for a whole day, and they still won't be charged completely. I'm very sorry I wasted my money on this, so please don't waste yours! I knew it was cheap when I bought it, but didn't think a product from a large company could be this bad. Oh, it hasn't completely failed, but I think it's ruined some nice Duracell NiMh batteries, probably from overcharging. And that's the main problem - the green light comes on as charging begins and never, ever goes off. Not designed to. So, as another reviewer mentioned, the batteries just keep cooking long after they should be done.

Here's the thing: how hard would it have been for Energizer engineers to include some sort of "done" indicator? It's awfully easy to forget about your batteries after the overnight period required for this kind of slow charger.

My fancy 2650 mAh Duracell AA batteries now won't last 2 days just powering a wireless mouse, let alone a camera. I hope a La Cross charger on order can revitalize them, at least somewhat. The new charger promises to provide all the info I need to tell how low the battery is and when it's done, and with a selection of charging rates. Really not much more cost considering the features.Arrived very quick and I mean lightning quick. I ordered it one day, got it before 2pm the next day. That's how I like my 2 day shipping. Product was in a very secure package and is exactly what the seller described. I highly recommend getting Amazon Prime.