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Model Forum / Radio Controlled / Air Models / July 2004New Batteries - CHEAP!
I was at one of the flying fields Sunday and one of the guys showed me a 4 cell NImnH pack he had made up from AA cells purchased from Harbor Freight. He said they cost him about $2 and cycled repeatedly at 772 mAHr. He has let them lay around for up to a week and not seen a significant decrease in reserved capacity. 2 questions. Is this reasonable for that type of cell? Is this a good deal or another hidden boondoggle? > AA cells purchased from Harbor Freight. > He said they cost him about $2 and cycled repeatedly at 772 mAHr. > 2 questions. > > Is this reasonable for that type of cell? 772 mAh out of a AA Ni-MH would put it in the catagory of junk when today's production AA Ni-MH are running above 1500 mAh. > Is this a good deal or another hidden boondoggle? I suspect this is an unloading of an OEM manufacturers surplus of unknown vintage and source. One could probably get some use out of them, but it would be prudent to keep a very close eye on them. Red's R/C Battery Clinic http://www.rcbatteryclinic.com Check us out for "revolting" information. > > AA cells purchased from Harbor Freight. > > He said they cost him about $2 and cycled repeatedly at 772 mAHr. [quoted text clipped - 15 lines] > http://www.rcbatteryclinic.com > Check us out for "revolting" information. Thank you Red. The guy looking at them is watching and does not trust them sincethe price was just too low - but not avoidable. I will share your comments with him. | I was at one of the flying fields Sunday and one of the guys showed | me a 4 cell NImnH pack he had made up from AA cells purchased from | Harbor Freight. He said they cost him about $2 and cycled | repeatedly at 772 mAHr. He has let them lay around for up to a week | and not seen a significant decrease in reserved capacity. Harbor Freight Tools does sell AA 700 mAh *NiCd* packs -- http://www.harborfreight.com/cpi/ctaf/displayitem.taf?function=Search&itemnumber =47440 Normal price is $5, but I've gotten them on sale for $2.50, and maybe they've been sold for as little as $2 at times. I've made battery packs out of them and they've cycled at around 750 - 800 mAh -- not too bad. They seem just fine, though I haven't torn any apart to see how their constructed, or tested them under extreme abuse. I've put a few of them into transmitter and receiver packs (on 0.40 sized planes) and have so far had no problems with them. | Is this reasonable for that type of cell? For a AA NiCd cell, 700 mAh is reasonable. For a AA NiMH cell, 700 mAh is really bad. If you want a slightly better battery, go to Lowes or Wal-Mart and get the 900 mAh AA NiCd packs for about $5. They're in the solar powered lights section and make very nice battery packs. | Is this a good deal or another hidden boondoggle? I think it's a good deal. Most consumers only want NiMH cells because of the increased capacity, so the NiCd cells are often sold cheaper, even though they're better for really high drain devices (like rechargable tools.) I'd certainly suggest cycling any packs you make a few times before flying with them, no matter what the source of the cells, and I'd also suggest cycling them once (to look for degrading performance) every month or so of use -- but I suggest that for any battery pack, professionally made or not.  SignatureDoug McLaren, dougmc@frenzy.com If Barbie is so popular, why do you have to buy all of her friends? > I was at one of the flying fields Sunday and one of the guys showed me a 4 > cell NImnH pack he had made up from AA cells purchased from Harbor Freight. > He said they cost him about $2 and cycled repeatedly at 772 mAHr. > > Is this reasonable for that type of cell? If all you're counting is $/mAH, it's not bad. If you figure $/(mAH*gram), it's not great. I recently bought 50 Sanyo AA NiMH cells, 1800 mAH with solder tabs for a buck apiece from www.batterystation.com. Check them out. SignatureCharles Wahl <remove uppercase letters in email address> | > I was at one of the flying fields Sunday and one of the guys showed me a 4 | > cell NImnH pack he had made up from AA cells purchased from Harbor Freight. [quoted text clipped - 4 lines] | If all you're counting is $/mAH, it's not bad. If you figure $/(mAH*gram), | it's not great. Well, the batteries he's referring to are almost certainly NiCd rather than the NiMH cells he said they were. Given that additional bit of information, they seem a good deal better than Red suggests. But cost, capacity and weight (parts of $/(mAH*gram)) aren't really the only things to consider. There's also resiliancy, internal resistance and physical size (of course, if you're only looking at AA cells, you've got the physical size fixed.) I've not seen any real empircal evidence of this, but from what I've heard NiCd cells are more resiliant than NiMH cells, handling overcharges, reverse charging and vibration better than NiMH cells. NiCd's lower internal resistance (for a given physical size, AA vs. AA for example) is easily verified. And their self discharge rate is lower -- also easily verified. And they can apparantly handle more charge/discharge cycles, but I've not verified this myself. The larger capacity NiCd packs for a given size seem to be more fragile than the smaller capacity ones -- like 1100 mAh AA cell vs. 600 mAh AA cell. Which makes sense -- they replace the internal components with smaller/thinner parts, leaving more room for electrolyte, which is where the energy is actually stored. For a receiver pack, especially on a glow plane where weight isn't quite the concern, NiCd packs are preferred to NiMH packs by many people. The lower internal resistance is good for times when all servos are struggling at once, and the increased resiliancy (?) helps prevents problems. Or it may just be that people are being conservative (which isn't a bad thing.) For a power pack for an electric plane, NiCd cells can dump power faster, making them better for a high performance plane. NiMH cells are probably better for a gentle flier. Of course, both are being replaced by LiPo at a high rate, making the question more and more moot. And there's a lot of overlap -- NiMH cells are getting better at dumping their power quickly (but not the AA cells -- they generally have a high internal resistance.) But for a transmitter pack, especially on a computer radio, I'd say NiMH cells rule. The only reasons I see for not replacing a NiCd transmitter pack with a NiMH pack are 1) you can get NiCd cells cheaper, or 2) you don't have a charger that can charge the pack in a reasonable time. | I recently bought 50 Sanyo AA NiMH cells, 1800 mAH with solder tabs for a | buck apiece from www.batterystation.com. Check them out. Not a bad price. I've been getting 2000 mAh AA cells from Frys when they're on sale -- either a 4 pack for $5, or a 10 pack for $10 -- but they're not always on sale. And not everybody has a Frys near by. (You really don't need solder tabs if you're careful.) SignatureDoug McLaren, dougmc@frenzy.com I used to have a handle on life, but it broke. > | > I was at one of the flying fields Sunday and one of the guys showed me a 4 > | > cell NImnH pack he had made up from AA cells purchased from Harbor Freight. [quoted text clipped - 7 lines] > Well, the batteries he's referring to are almost certainly NiCd rather > than the NiMH cells he said they were. YOU ARE WRONG > Given that additional bit of > information, they seem a good deal better than Red suggests. [quoted text clipped - 47 lines] > they're not always on sale. And not everybody has a Frys near by. > (You really don't need solder tabs if you're careful.) | > Well, the batteries he's referring to are almost certainly NiCd rather | > than the NiMH cells he said they were. | | YOU ARE WRONG Did you really need to quote my entire post just to say that? In any event, I doubt I'm wrong. If the batteries are AA, and if Harbor Freight Tools sold them, and if the rated capacity is 700 mAh, then they're almost certainly NiCd. If some of these things are not true, then maybe not. But it seems an awfully big coincidence that they DO sell AA NiCd batteries with exactly the promised capacity, at approximately the promised price. The AA NiMH cells they sell have higher ratings -- I can't be sure of the exact rating because I don't have any in front of me. But I do have the AA NiCd pack in front of me, and they match the promised specifications very closely. If there's any doubt, the NiCd cells sold by Harbor Freight Tools/Chicago Electric are generally orange colored, and the NiMH cells are green. Has *anybody* ever sold 700 mAh AA sized NiMH cells? The lowest capacity AA NiMH cells I've ever heard of were 1000 mAh, and that was back in 1992 or so when NiMH cells just came out. (Now, if these are AAA cells rather than AA, then a 700 mAh rating makes perfect sense, because 700 mAh is a very common AAA NiMH cell rating.) And if he did by some freak of nature get 700 mAh AA sized NiMH cells from Harbor Freight Tools, then you should know that they also sell 700 mAh AA sized NiCd cells for about $2.50 for a four pack (when they're on sale -- every few months), and that they seem to work very well for RC applications. SignatureDoug McLaren, dougmc@frenzy.com Our OS who art in CPU, UNIX be thy name. Thy programs run, thy syscalls done, In kernel as it is in user! > | > Well, the batteries he's referring to are almost certainly NiCd rather > | > than the NiMH cells he said they were. > | > | YOU ARE WRONG > > Did you really need to quote my entire post just to say that? Well....yes. And the last paragraph of THIS post finally addresses what I saw, NOT what he told me. The cells said "NiMH". That was one of the reasons I asked the question in a public forum, knowing there would be some sure to tell me how stupid I am. Thanks for the extra information. > In any event, I doubt I'm wrong. If the batteries are AA, and if > Harbor Freight Tools sold them, and if the rated capacity is 700 mAh, [quoted text clipped - 24 lines] > they're on sale -- every few months), and that they seem to work very > well for RC applications. [ If I had an email address for you, I'd email this. But I don't think I have a valid one. This thread has gotten very tired ... ] | > | > Well, the batteries he's referring to are almost certainly NiCd rather | > | > than the NiMH cells he said they were. [quoted text clipped - 5 lines] | Well....yes. And the last paragraph of THIS post finally addresses what I | saw, NOT what he told me. The last paragraph of that post really said nothing that I hadn't said in my original post -- that HFT sells 700 mAh AA NiCd cell packs for $2.50 or so (when on sale) that work very well. | The cells said "NiMH". Ok then. Tell you what. You send me (ask offline for my address) a four cell AA NiMH battery pack (new or used, soldered into a pack is fine) that was made with cells from Harbor Freight Tools, labelled (by the factory!) at about 700 mAh. If you can provide a receipt saying the pack was less than $5.00, that would be nice too, but it's not required. If I find the pack provided to match the required specifications (must be AA sized (not AAA), NiMH (not NiCd), the manufacturer label saying 700 +/- 100 mAh, from HFT/Chicago Electric), I'll send you back a AA sized four cell pack, either NiMH (probably 1800-2000 mAh) or NiCd (probably 700-900 mAh), your choice. And I'll give you $20 (twenty dollars) more for your trouble. If the pack received does not match the required parameters, I will not send back anything except an email about exactly how it did not match. (Unless you pay for the additional shipping -- then I'll ship the pack back.) Since all the required parameters are easily verified without even opening the pack, it should be very easy to be sure to meet my requirements before you even pay for the pack. And either way, I'll post the results here. If I'm wrong (in saying that HFT couldn't have sold a AA NiMH 700 mAh rated pack), I'll include a statement to that effect. If you're right, it's an easy $20 (minus a few dollars shipping) and you (or your friend) will get a better battery pack for just a few dollars. And you'll be be publically vindicated (which is always nice.) I will make this offer valid for one month from today, through August 12, 2004. | That was one of the reasons I asked the question in a public forum, | knowing there would be some sure to tell me how stupid I am. Having somebody point out that you (or your friend) probably made a mistake or typo is not the same thing as calling you stupid. SignatureDoug McLaren, dougmc@frenzy.com `Those are my principals, if you don't like them...... I have others.' -Groucho Marx Please re-read the first post in the thread. I simply reported what I was shown and told and asked the group for some answers because the data did not seem clean. > Please re-read the first post in the thread. I simply reported what I was > shown and told and asked the group for some answers because the data did not > seem clean. I stopped at a Harbor Freight store.....only 3min from were I work and checked out the batteries: 700 mah NiCd AA, 4 to a pack, color of batteries were black and orange ( if this means anything lol )....price $4.99 Mike | > Please re-read the first post in the thread. I simply reported what I was | > shown and told and asked the group for some answers because the data did not | > seem clean. | I stopped at a Harbor Freight store.....only 3min from were I work | and checked out the batteries: 700 mah NiCd AA, 4 to a pack, color | of batteries were black and orange ( if this means anything lol | )....price $4.99 Wait for them to go on sale for $2.50 or $2.99. If you need batteries now, go to Wal-Mart. In the solar powered light section, they sell 900 mAh AA 4 packs for $5.17. Lowes sells 900 mAh AA 4 packs for $5.99, and Home Depot sells 800 mAh 4 packs for $5.99. Again, with the solar powered lights. `Solar powered lights' ... doesn't quite seem right, does it? :) I've tried all of these and they've all been just fine, and I've got several planes and a few rechargable tools using them. Haven't had a failure yet -- and yes, I do cycle them occasionally to check for age. I've yet to throw out any of the packs I've made -- though it's only been about a year I guess. SignatureDoug McLaren, dougmc@frenzy.com Logic ... merely enables one to be wrong with authority. -- Doctor Who > | > Please re-read the first post in the thread. I simply reported what I was > | > shown and told and asked the group for some answers because the data did not [quoted text clipped - 20 lines] > I've yet to throw out any of the packs I've made -- though it's only > been about a year I guess. I checked those out at Wal-Mart.....never knew they had them. Now I know and will make a few packs up for my SS. TY Mike Doug, While I appreciate your offer and am sure you are right, it is NOT worth the aggrevation. I was TOLD the cost and I was TOLD the capacity and I SAW the cells. I did NOT read the fine print because I didn't trust them in the first place. Thank you for the gracious offer. Jim Branaum. p.s. Yes, you DO have a valid e-mail address. Gave it to you in April. > [ If I had an email address for you, I'd email this. But I don't > think I have a valid one. This thread has gotten very tired ... ] [quoted text clipped - 55 lines] > Having somebody point out that you (or your friend) probably made a > mistake or typo is not the same thing as calling you stupid. |
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