There it is... the good name of erco is forever besmirched and shall henceforth be associated exclusively with plywood-based robots that can't quite make it back to their autodock recharging station, due to their lower-than-expected capacity Chinese NiMH cells.
Should I charge it fully before bandsawing it open lengthwise?
It will be hard to return if you cut it open.
Also, you better hope that they haven't counterfeited the battery by putting in a tiny lithium battery and associated circuitry/voltage divider/etc. to make it look like a NiMH. You wouldn't want to cut into that. I don't think it's too likely.
If I were going to open one, I'd start by peeling away the label if possible. You may even find something interesting under it. Then I'd see if I could remove one of the ends. You may be able to pry the casing away from the end. If not, I'd probably take a razor saw and work my way around the circumference of the casing near the end rather than sawing straight through.
Mine haven't arrived yet but I'll test and report when they do. The safest way to charge these is at 1/10 the mAH capacity for 14 hours. Since we don't know the true mAH capacity I would probably aim for 100 mA and see if the cells start to get warm after 8 hours or so. Also, the very first charge might need to be longer.
I will be fairly happy if I get 700 mAH since that compares favorably with the performance of low-end NiCD's, which are still over $2/each locally. It's a very cheap way to see if the robot project becomes interesting enough to justify springing for the real deal at 5 x $6.00 / cell.
I just got identical discharge results with two different batteries, quick-charged with the first two, so my numbers stand. I'll trickle these same 4 cells for 14 hours and report back.
That's a pretty good deal too, Phil. I might try those next if I need more capacity than the Chinese cells deliver. But honestly, I probably won't for awhile, because another project came up and once I get the robot fully tested out it will probably take longer than I was planning to get the software done. I'd like it to be able to spend a full day roaming but there's no need for that until it learns to figure out where it is.
I've never used Ansmann batteries, but I've ordered most of my MAHA/Powerex stuff from Thomas Distributing and I've always been happy with the service and what I bought.
Man, I'm an AnsMann man all the way. I bought their Energy 8 charger after the RadioShack unit I had nearly caught my house afire. I've been very happy with it. It even breathed new life into some cells I thought the RS charger had ruined. (Disclaimer: That's a totally subjective evaluation. No quantitative testing has been done. I put dead batteries in it and take charged batteries out. Life is simple and good.)
On the strength of Dr. A's recommendation, I ordered a Wizard One (via slow boat). It arrived today. Gotta say that I'm VERY pleased with it. At the moment, it's beating on some recalcitrant Energizer cells which have been a source of grief ever since I bought them.
As much as I like La Crosse chargers, this device is clearly superior.
BTW, I contacted the seller and got a 50% refund, which I think is fair, in exchange for not leaving any feedback at all. (I bought 2 twelve-packs at $6.77 each.) I advise everyone to do the same. Their reply:
Hi, OK, we will refund USD6.77 to you by today, please don't leave any feedback .
thanks
I finally got my "3000 mAH" AA's. Arrived "charged" but with a light bulb drawing 140 mA the voltage began to drop precipitously at 2 hours. Still, they may not have been *fully* charged.
Working on the assumption that they might only be 700 mAH cells, it should be safe to charge them indefinitely at 70 mA. I have just installed them with a 100 ohm series resistor on a 12 volt regulated power supply. A couple of days should give them a nice full charge if they really are 3000 mAH cells, and not hurt them if they aren't. So I figure Sunday we will find out what they are made of.
EDIT: By "them" I mean a pack of 4, nominal total voltage a bit less than 5V.
Yes, I assume these cheapie cells self-discharge quickly. (And go blind shortly thereafter.)
I'll be curious to hear your findings. Phil may be right; if we cut one apart, there might be a nice 700 mAH AAA hiding inside, in which case I'd be quite pleased.
Phil may be right; if we cut one apart, there might be a nice 700 mAH AAA hiding inside, in which case I'd be quite pleased.
Well, I need 5 so even after reserving a complete spare set I have two extra, and a garage full of lapidary equipment that will cut through just about anything, so if you'd like to know what they look like inside just let me know. I'm sure that after fully draining them they won't tryto melt the diamonds off my trim saw.
BTW, I contacted the seller and got a 50% refund, which I think is fair, in exchange for not leaving any feedback at all. (I bought 2 twelve-packs at $6.77 each.) I advise everyone to do the same. Their reply:
Hi, OK, we will refund USD6.77 to you by today, please don't leave any feedback .
thanks
- ecomoutlet
It's good to hear you got something back and are happy with the result, but doesn't this just allow them to keep ripping people off? They are still misrepresenting the product. And this is advocating that it's ok, as long as they bribe the people that find out.
I def see your point, but IMHO it's a culture thing. China is a bunch of little guys struggling to stand out from the crowd with a "better" product. They aren't making huge profits one way or the other at these prices. The honest guy who advertises these as 700 mAH would never sell one. His neighbor says 800, the next guy says 1100, etc. It's hard to prevent individuals from jumping on this bandwagon. Negative feedback about this mAH rating is effective only if people take the time to read the comments. Overall, the "hard damage" to the seller is not quantifiable. I figure taking money back from the seller hits him squarely in the pocket book and is a better way to discourage him. Face it, on Ebay, everyone has to have their guard up.
The 4 cell pack I tested earlier has now been charging at 70 mA for over 50 hours, so it should be fully charged and undamaged no matter what its capacity. The voltage across the pack has been 5.75V for the last day or more, but dropped to 5.25 as soon as the light bulb went on, suggesting the internal resistance is about 0.8 ohms per cell. That suggests the pack probably can't supply more than 2 amps dead shorted and probably no more than a couple of hundred mA without wasting much capacity on internal heating. Quite a change from my last battery pack, a set of Cyclon spiral lead cells that could -- and on a couple of occasions did -- supply pulses of several hundred amps.
Anyway it's dischargingat 150 mA, so if it's as bad as we suspect they should be dead before I turn in for the evening. If they're not I'll stop the experiment and continue tomorrow.
I'm pretty sure it takes several charges (3 or 4) to bring a NiMH up to its full capacity.
I'm also not so sure leaving a batty to charge for 50 wont have a detrimental effect on it.
I read that instead of trickle charging batteries one wished to keep topped off, it was better to charge at a higher current for about ten minutes a day.
A continuous trickle charge can cause some sort of problem. I think it was nickel migration. It shorted the life a battery.
I doubt your 50 hour charge would cause damage but I'm not sure it this is a very accurate way of determining the capacity of these batteries.
Duane, I based this on what many battery sites say about charging for NiCD and NiMH. While it is not recommended to leave these batteries on trickle charge forever, leaving them on less than 1/10 their total capacity for extended periods does not damage them. Higher charge rates damage the batteries if you overcharge them. NiMH are problematic to charge correctly because there is no reliable voltage/current way to tell they are overcharging; the best fast chargers actually measure the temperature of the batteries and stop charging when they start to heat up. That's further problematic with these batteries because of their high internal resistance.
These batteries arrived with a pretty strong charge so they have already been charged at least once. I'll run another cycle but I doubt there will be improvement to the tune of tripling this result.
FWIW I"m not all that disappointed and I think these batteries are still a good deal, as long as you understand what you're getting. The cheapest NiCD's of similar capacity are still over two bucks a cell locally. If the capacity is adequate and you don't need fast charge or high current discharge (for example, for park flier model airplanes) then these are a very cheap way to get a more modest capacity.
Obviously they don't need to be charged for 50 hours to return 900 mAH; that was just in case they were what they claimed. Now that I know the true (likely) capacity I would charge at 90 mA for 12 to 14 hours. Again, that rate is chosen because it's safe to overcharge at that rate. If you know the cells are fully discharged you can charge them faster.
Surprise! My "3000 mAH Ultrafire" Li-Ion pooped out at about 950 mAH (rough swag). Initial no-load voltage was 4.1V. It was hooked up to an electric motor, initially drawing 830 mA; after 60 minutes down to 600 mA@2.9V, then after 90 minutes 420 mA@1.7V. Just barely warm to the touch after an hour. Sure, it'd give better numbers at lower current, or intermittent use, but like the NiMH cells, that's quite a bit different from the advertised rating.
Buyer beware. At $2-3 a battery, they're still a good value for general purpose use. Just don't build 'em into mission critical apps.
Comments
I have heard of this happening before. I think it was D cells with AAs inside or something similar.
It's also been known to happen with capacitors - large shells with small capacitors inside.
There it is... the good name of erco is forever besmirched and shall henceforth be associated exclusively with plywood-based robots that can't quite make it back to their autodock recharging station, due to their lower-than-expected capacity Chinese NiMH cells.
Should I charge it fully before bandsawing it open lengthwise?
It will be hard to return if you cut it open.
Also, you better hope that they haven't counterfeited the battery by putting in a tiny lithium battery and associated circuitry/voltage divider/etc. to make it look like a NiMH. You wouldn't want to cut into that. I don't think it's too likely.
If I were going to open one, I'd start by peeling away the label if possible. You may even find something interesting under it. Then I'd see if I could remove one of the ends. You may be able to pry the casing away from the end. If not, I'd probably take a razor saw and work my way around the circumference of the casing near the end rather than sawing straight through.
I will be fairly happy if I get 700 mAH since that compares favorably with the performance of low-end NiCD's, which are still over $2/each locally. It's a very cheap way to see if the robot project becomes interesting enough to justify springing for the real deal at 5 x $6.00 / cell.
http://www.thomasdistributing.com/Ansmann-Max-e-2100mAh-AA_p_795.html
But I notice that Ansmann has another low-self-discharge AA with a higher stated capacity:
-Phil
Your to funny
I removed the label and there's nothing but a vienna sausage inside!
I've never used Ansmann batteries, but I've ordered most of my MAHA/Powerex stuff from Thomas Distributing and I've always been happy with the service and what I bought.
The author is also a strong advocate of Maha chargers. PLUS, he built a battery tester using a Basic Stamp!
-Phil
I should have mentioned that they were AAA, like the ones BradC was talking about. In fact, these are they:
http://cgi.ebay.com/4-x-1-2V-1000mAh-AAA-Ni-MH-Rechargeable-Battery-8781-/110651559912?pt=US_Batteries&hash=item19c358cfe8
I don't care beans about the money, but it's hard to give five stars to a sham.
BTW, Of the 20+ brands I've tested, these are my favorite:
http://www.amazon.com/gp/product/B004WLNPQO
As much as I like La Crosse chargers, this device is clearly superior.
I'l be curious to know what mAH reading you get off these "3000 mAH" batteries.
Hi, OK, we will refund USD6.77 to you by today, please don't leave any feedback .
thanks
- ecomoutlet
It's the best price I found, with the seller paying the shipping.
Of course what I have are the so-called 1000 mAH AAA cells (see post 45). I'll measure their capacity next.
Seems like a great way to handle it. Not that you need the $6.77, but it clips them a bit for misrepresenting the product.
Working on the assumption that they might only be 700 mAH cells, it should be safe to charge them indefinitely at 70 mA. I have just installed them with a 100 ohm series resistor on a 12 volt regulated power supply. A couple of days should give them a nice full charge if they really are 3000 mAH cells, and not hurt them if they aren't. So I figure Sunday we will find out what they are made of.
EDIT: By "them" I mean a pack of 4, nominal total voltage a bit less than 5V.
I'll be curious to hear your findings. Phil may be right; if we cut one apart, there might be a nice 700 mAH AAA hiding inside, in which case I'd be quite pleased.
Well, I need 5 so even after reserving a complete spare set I have two extra, and a garage full of lapidary equipment that will cut through just about anything, so if you'd like to know what they look like inside just let me know. I'm sure that after fully draining them they won't tryto melt the diamonds off my trim saw.
It's good to hear you got something back and are happy with the result, but doesn't this just allow them to keep ripping people off? They are still misrepresenting the product. And this is advocating that it's ok, as long as they bribe the people that find out.
Anyway it's dischargingat 150 mA, so if it's as bad as we suspect they should be dead before I turn in for the evening. If they're not I'll stop the experiment and continue tomorrow.
70 mA x 50 hour input, 150 mA x 6 hours out. Not a great ROI!
I had in mind to use these in a solar cell application. Charge all day, use at nite. I think I'll be better off with LiPo or even lead-acid.
I assume this was just the first charge cycle?
I'm pretty sure it takes several charges (3 or 4) to bring a NiMH up to its full capacity.
I'm also not so sure leaving a batty to charge for 50 wont have a detrimental effect on it.
I read that instead of trickle charging batteries one wished to keep topped off, it was better to charge at a higher current for about ten minutes a day.
A continuous trickle charge can cause some sort of problem. I think it was nickel migration. It shorted the life a battery.
I doubt your 50 hour charge would cause damage but I'm not sure it this is a very accurate way of determining the capacity of these batteries.
Duane
These batteries arrived with a pretty strong charge so they have already been charged at least once. I'll run another cycle but I doubt there will be improvement to the tune of tripling this result.
FWIW I"m not all that disappointed and I think these batteries are still a good deal, as long as you understand what you're getting. The cheapest NiCD's of similar capacity are still over two bucks a cell locally. If the capacity is adequate and you don't need fast charge or high current discharge (for example, for park flier model airplanes) then these are a very cheap way to get a more modest capacity.
Obviously they don't need to be charged for 50 hours to return 900 mAH; that was just in case they were what they claimed. Now that I know the true (likely) capacity I would charge at 90 mA for 12 to 14 hours. Again, that rate is chosen because it's safe to overcharge at that rate. If you know the cells are fully discharged you can charge them faster.
Buyer beware. At $2-3 a battery, they're still a good value for general purpose use. Just don't build 'em into mission critical apps.