Rayovac 15 minute charger ..... final verdict?

I know there was a pretty lengthy thread on this charger. Now that it has been out a while and people have had a chance to use it more ....... is it a "buy" or "don't buy"?


Mike

I can't call it a "buy" or "don't buy" yet, but I can say that I've had one for a couple of months, and I recently got the DC car adapter. I haven't had any problems at all. I like the fact that I can get 8Wh of juice loaded up in a mere 15 minutes.

Only thing I would like is separate LEDs for each circuit, and I do wonder what would happen if the fan failed. Only time will tell, I guess.

I seem to remember that it's not just a charger but a combined charger/battery system, i.e. it needs special batteries that are set up for such fast charging. I don't know if the batteries have any special charge or temperature sensing contacts that are separate from the usual terminals. I have several dozen NiMH AA's of various brands acquired over the years so I wouldn't want to replace them all with new expensive Rayovacs just to be able to charge them in 15 minutes. It's fairly easy to just always keep some spare charged ones around instead. There are some nice 1-2 hour chargers available and I haven't even yet really felt the need for one of those; I'm doing fine with several cheap 4 hour chargers.

I've been using the Rayovac 15 minute charger and the corresponding AA MiMH batteries with excellent results. I love the short charge time. I hate the fan noise, but I just plug it in a room where I am not. The fan shuts off automatically when it's no longer needed so it's not much of an issue.

I have the two battery model which is very compact and good for traveling. The two-battery version doesn't need an external power supply.

One of the reasons I'm looking into this one is because I do not currently have a battery charger. So having to use their special batteries isn't an issue. But it would be if I already had a charger and a bunch of batteries. Was thinking of using it primarily for my Arc LS with the 2AA tail switch, Arc AAA, wireless keyboard and mouse.

Also, does it have a feature to keep from over charging the batteries?

Guess I should have put all that in my first post.

Thanks for the input.

Mike

Any batter charger that fast MUST have overcharge and temperature sensing. In practice even if you have no rechargeables already, it may not be worth getting locked into one brand of cells. You can get good NiMH cells for $1 apiece or so if you shop around. Slower chargers don't have any fans making noise, so they won't keep you awake if you charge your cells overnight.

Rechargeables are a good match for those AA devices you list. Runtime will be reduced on the LS compared to alkalines, but who cares? However, running the Arc AAA on a rechargeable, while it works fine, doesn't really seem worthwhile, since the AAA runs for so long on an alkaline that the expense is negligible--unless you really use it a lot. Otherwise it's probably more convenient to go with the long shelf life and slow voltage decline of alkalines, so you can leave the battery in the light for years and get around to changing it when you notice the light has gotten dim. Rechargeables self-discharge after a few months and need recharging, and have steady output til they go flat rather suddenly, possibly leaving you in the dark.

The problem I see is you have to buy the specific batteries made for that charger, or at least you should. If you buy a MAHA 204 or 401 (or similar smart charger) you can use any NiMH batteries. So as time goes on and you get larger capacity batteries you can continue to use the same good charger, and add more batteries.

The big advantage is the charge time, but I like many, find have a couple of extra sets seems to be the easiest and cheapest way to go in the long run.

I think each product is made for a specific use and has a place, I just don't need 4 batteries charged in less then 1 hour, so it isn't really necessary for me. For some it is a must.

I just saw this charger this afternoon at Walgreens. It charges the special 15 min batts and regular NiCad or NiMH overnight. It says so on the package.

Does the charger monitor each cell separately?
Also, can you charge a single cell?
Sounds like the fan is annoyingly loud.

Let me add a few points:

1) The charger and batteries work together to achieve the 15 min. charge time. You can use any NiMH batteries in the charger, and you can charge the special batteries (IC3) in any NiMH charger, you just can't do either in 15 min.

2) Hmmm. Fan is loud, perhaps, if you are in a quite room. With the TV on, or while charging in a car, it's not really an issue. To tell you the truth, I think it's a fairly quite fan, but it's still a fan so it's going to make a little noise. I don't think anyone should get the impression that the fan is tremendously loud, because it isn't.

3) I would think Rayovac would come out with higher capacity IC3 batteries also as the technology improves.

4) Charger monitors each cell individually, so you can charge only one cell. It's just that it has only one LED for each pair of batteries, which is kind of stupid.

AHHH, thank you for that clarification and sorry about the confusion.

I have one, and I would say buy it if you need to charge more than 4 batteries at a time. It's really nice to be able to charge 6 (or 8) batteries in half an hour. Then you can let them settle overnight.

If you only need to charge 4 batteries or less, at one time, then get the Lenmar Mach 1, because it gives you more flexibility when buying batteries.

Few weeks ago, Walgreen Pharmacy had the 15-charger_with_2_batteries for $27.98. They also threw in a 4Pk AA set for free! So for $28.00 you got 6 15-min batteries and the 15-minute charger. That was a great deal for somebody who is starting new with NiMh setup. The 4pk is priced about $14; so it is expensive compared to others but not outrageously so.

I have stocked up on the Dynacharge rechargeables, so I was not looking.

- Vikas

the best rechargable batteries and charger come from powerex. they come in 2200 mah. you can get them at
http://www.thomas-distributing.com. i have had mine forever it seems and no problems yet. you can also check reviews from various places online and they will tell you the same thing/.

I've got one of these chargers and 8 AA an 4 AAA cells in January. Here you pay 59? for the charger with 4 AA cells (that is about $75, the price you have to pay to live in old Europe .-)
It is branded 'Varta' here, a company not famous for good rechargeables.
And the 12V power cord comes 2 months later when you sent in a questionaire (and getting even more spam).
Varta told me, that their wall wart only works on 230V and not in between 100-250V like the US version (but I don't believe them).
Unfortunately US vendors seem not to be allowed to ship them abroad.

Anyway, the technical part:
I have tested the cells when they came, they ranged in between 1850 and 1900 mAh after the third charge (at 0.8-1.2A). A very good value, only about 5-7% below the statd value. All my other cells (1800-2200 mAh) are usually less than 7% below their rated capacity. Usually, the higher, the wronger.
But in pratical life, the ability for fast charging counts much, much more than a little bit more (nominal?) capacity.

As the cell 'monitors' it's internal pressure, this is much safer than any external detection of the charge state (voltage, voltage change over time, surface temperature). This also acts as an overtemperature protection. And against fast charge on cold cells.

Actually many people (including myself) have waited for a charging system which monitors cell pressure for decades. There are lots of fast and very fast chargers, but almost all of them work on assumptions about the cell's behaviour which are only true for maybe 95% of all cases. In the rest, the cells get overcharged with a high current. When your overtemp shut off is triggered, your cells are already damaged a little bit. And they collect their scars.

If the IC3 system works as expected (and everything now looks like it does), the cells should have a long life.

My only complaints are, that there are only two LEDs, not each for each cell (as over people have stated already).
The charger detects the IC3 cells by their conductive ring at the bottom, so if you insert just one of two cells not careful enough, it may not get the full charging current (I have to check that, I have the suspicion that cells get the same current).
I will check the cells after 30 or 50 cycles and post the results here.

One funny thing: When I got the cells I put them into my smart chrger to check their capacity and selected the program which cycles several times. But it did not work. Some cells showed 'error', and some a very low charging capacity (14mAh or something like that).
A moment later I realized what I made wrong: When the cells are charged, they shut off when they are full and confused the smart charger. So I only use the smart charger for discharging them (to get the capacity reading).

As the IC3 charger only needs 15 maximum, the fan noise is no issue. Actually, it is a feature, because when it stops, the last cell is full.

Last month I used the charger and cells on an expedition with very unrelyable power. The generator gives in between 150 and 250V (actually 390V maximum) and the charger did not care about the voltage change. I think it is the same device as sold in the US, just with the European plug.
Several expedition members will buy IC3 cells and chargers when we can find a source in the US which ships to Europe.

I will throw out my other AA and AAA cells ASAP.

I have the Rayovac 15 minute charger, and I always measure 1.457 volts after the batteries are charged. So I think if one battery of a pair needs more charge than the other one, the first one to finish charging will be getting trickle charged while the other one is finishing up.

I completely agree that fast charging speed is by far the most important factor. It prevents you from needing extra batteries, and allows you to top off your batteries every time you use them.

By the way, rechargeables will last a lot longer if they are recharged more frequently.

There is an Energizer 30 minute charger which doesn't require special batteries - another option.

I have the Energizer 30 minute charger. It works great, most of the time, it works in less than 20 minutes because i never drain the battery all the way. One potential problem is the heat that the battery reaches.

I have the Ray-O-Vac iC3 charger and I really like it. I use the batteries mostly for my digital camera. I find it really handy to be able to charge the batteries in my car in only 15 minutes. It sure beats having to carry around lots of spare batteries. (Most of us know how much digital cameras love to go through batteries) I'll have to check out the Energizer 30 minute system. Does anyone know if it can be used in the car like the Ray-O-Vac iC3 system?

Just an update. Still no problems.

One other thing: I vaguely recall reading somewhere that the charger actually does have 4 separate circuits, but only has 2 LEDs. Unfortunately, I threw out the documentation that came with the charger, but can anyone else verify that?

[ QUOTE ]
LightScene said:
I have the Rayovac 15 minute charger, and I always measure 1.457 volts after the batteries are charged. So I think if one battery of a pair needs more charge than the other one, the first one to finish charging will be getting trickle charged while the other one is finishing up.

[/ QUOTE ]

As LuxLuthor mentioned, all 4 slots are independent. The just saved 2 LEDs. Silly in one one, but on the other hand, as the charge cycle only lasts 15min max, there is not much time too loose (in the case you have to charge more than 4 cells and they are discharged to different levels).

And the problem with almost all the other 30min or whatever fast or rapid chargers is, that they are by far not as relyable to detect the ned of charge state. Thereofre overcharging from time to time, resulting in some capacity loss. And overcharging is the culprit for many cases of ill behaving NiXX cells (usually blamed on the 'memory effect', it is always very convenient to have a single suspect)
But we will see how large the capacity loss for the IC3 cells is after some cycles.

One more thing, I like is the relatively small size and weight of the charger (flying to expeditions is always a weight problem).

And no, regularly used cells are not necessarly better than long time stored ones. It may depend on your application, I have several cases where it is actually the opposite.

I do not care about the voltage (as long as it is not excessivly high or low).

One set of 4 AA cells is dedicated for digital camera use. You know the situation: My wife needs it sometimes for her work and she tells me usually at 6:30 in the morning. And I hate to waste alkalines in these cases.
And my youngest son (flashaholic, don't know why) empties his Lambda Micro twice a week.