ezzo 0 Report post Posted October 3, 2007 Hey, I just bought a PowerPack "Product of Singapore" 9V 210mAh NiMH rechargeable battery. I always believed the brands matters, but anyway, I still got it. The performance seem to be quite poor for a 210mAh battery. Have anyone had experiences with not-so-reputated brands for them?? There is another thing, do NiMH batteries suffer from memory effects? Share this post Link to post Share on other sites
dridiot 0 Report post Posted October 3, 2007 NiMh = no memory effect. Share this post Link to post Share on other sites
ezzo 0 Report post Posted October 3, 2007 (edited) Are you 100% sure? Quoted from Wikipedia: "A NiMH battery can have two to three times the capacity of an equivalent size NiCd and the memory effect is not as significant" and "Voltage Depression ("Memory Effect") from repeated partial discharge can occur, but is reversible through charge cycling." ??? There are also many people saying it does not suffer from memory effects. Pretty confusing.. Edited October 3, 2007 by ezzo Share this post Link to post Share on other sites
heady 0 Report post Posted October 3, 2007 Quoted from Wikipedia: "A NiMH battery can have two to three times the capacity of an equivalent size NiCd and the memory effect is not as significant" and "Voltage Depression ("Memory Effect") from repeated partial discharge can occur, but is reversible through charge cycling." What this means is that if you recharge before the battery is completely discharged, then there will be memory effect, ie the battery holds less charge. But this can be "cured" by discharging the battery completely and then charging it until it reaches full capacity. So effectively, NiMH battery do not have the memory effect. Share this post Link to post Share on other sites
ezzo 0 Report post Posted October 3, 2007 Ah, that got me clear, thanks. Oh wells, you still cant use it like Li-ion batteries though. How about "lousy" branded rechargeable batteries? Anyone? Share this post Link to post Share on other sites
rko 0 Report post Posted October 3, 2007 What this means is that if you recharge before the battery is completely discharged, then there will be memory effect, ie the battery holds less charge. But this can be "cured" by discharging the battery completely and then charging it until it reaches full capacity. So effectively, NiMH battery do not have the memory effect. For note, Nimh does not like to be totally discharge, in fact this kills the life span of the batt. Preferably discharge to to .6 or .9 volts/cell under low loads if i remember correctly. I believe the memory effect talked about means when u recharge the battery before it is depleted to .6/.9 volts. Ah, that got me clear, thanks. Oh wells, you still cant use it like Li-ion batteries though. How about "lousy" branded rechargeable batteries? Anyone? Imho, do not go for unbranded rechargeable. Different brands/models have different characteristic but i have seen exploded battery when they are not charged properly. Share this post Link to post Share on other sites
ezzo 0 Report post Posted October 3, 2007 I believe the memory effect talked about means when u recharge the battery before it is depleted to .6/.9 volts. Exactly! But the standard meaning of memory effect means permanently reducing the capacity. Imho, do not go for unbranded rechargeable. Different brands/models have different characteristic but i have seen exploded battery when they are not charged properly. Yea, even buying Product of Singapore batteries are very likely to be lousy. I just got one not long ago and it sucks. Share this post Link to post Share on other sites
dridiot 0 Report post Posted October 4, 2007 So whats the diff between lousy rechargeables and the good ones? Share this post Link to post Share on other sites
ezzo 0 Report post Posted October 4, 2007 The thing is, you have no idea if its stated capacity is true. With a reputated brand, you can trust what it states. From my experience, DONT BUY THE NON-REPUTATED BRANDS. Looking forward to hear about other's experiences too. Share this post Link to post Share on other sites
rko 0 Report post Posted October 4, 2007 So whats the diff between lousy rechargeables and the good ones? As i mentioned before, different batteries have different characteristics as they are designed for different uses. Some models are design for hospital equipment, some for ur portable, some from hobby usuage. These batteries perform differently under different loads.(Hospital ones provide more consistence voltages while hobby ones usually can handle big and fluctuating loads). It isnt easy to identify which one is "best" for ur application unless u know how the batts perform and how u are going to load the batts. General speaking, reputated ones from sanyo, GP are pretty okay regardless what functions they are designed for. Also pair them up with a decent charger. One that does individual peak charging and hopefully help to cycle batts. Share this post Link to post Share on other sites
ezzo 0 Report post Posted October 4, 2007 That would be the best, but I just stuff my maha battery in my headphone amplifier and charge it from there. That should be able to last till the new batteries are out on the market. If you read, they last around 3years, yeah 3 years of usage without charging, you just throw them after that Share this post Link to post Share on other sites
dridiot 0 Report post Posted October 5, 2007 Also, I have read that Sanyo makes pretty reliable rechargeables.... Share this post Link to post Share on other sites
heady 0 Report post Posted October 5, 2007 Also, I have read that Sanyo makes pretty reliable rechargeables.... For AA and AAA batteries, I will definitely agree. But I have not seen a Sanyo 9V, maybe they do make it but I have not seen any so far. Share this post Link to post Share on other sites
