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Gear / Technical Help => Remote Power => Topic started by: Gutbucket on August 22, 2008, 11:09:46 AM
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Anyone use or have insight into Ultra Low Discharge vs standard NiMH rechargeable AAs?
The Ultra Low Discharge versions have a lower total mAh rating but slower self discharge rate, retaining around 80% charge after many months instead of the standard versions that loose most of their charge after a month or so.
Except for festivals where I need as long a runtime on each battery set as possible, I recharge the batts after or before each show so the lower mAh rating should not be a problem as they should still run longer than standard alkalines. I'd rather recharge after a show and be sure the batteries are good for the next one a day, two days, a week, two weeks or three weeks down the road instead of remembering to recharge the batteries the night before after a lull.
Any difference in memory-effect, life-span, and ultimate graceful (or not) death?
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I've been using Sanyo 2000 mAh eneloops for a while and they work great. Most of them actually tested out at 2150+ mAh when I conditioned them with a LaCrosse BC-900 charger.
With 4 of them in a Gomadic battery extender I was about to run a Microtrack 1 with a new, fully charged battery for around 10 hours, so they have plenty of power.
They hold their charge well too. Still test out as fully charged after sitting around a month or more, although they may only be 90-95% charged at that point. Don't know about the lifespan or memory effect though.
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I second the positive review of Sanyo's Eneloop cells (as well as the Oade-recommended BC900, which is just plain good gear). I not only use Eneloop cells as my primary PMD660 battery, I have pairs in my television and DVD player remote controls. I've only been using them for a couple of months and their performance has been more than satisfactory thus far. If anything out of the ordinary happens with these cells, you'll read it here first.
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anyone have a rough guess on how long these 2100-2300 mAh batteries are going to last in an R-09?
I think I'm going to order a bunch since I need some new cells anyway, but I don't want them if they're going to be the kind I'll have to swap after 3hrs or so. I'm used to getting 6 with my current batteries so I can just set up and roll and chop it down in post and never have to worry about my power dying on me...
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On request I could charge up some Eneloops, test in an R-09 and report back in a day or so. However (someone correct me if I am wrong) I think how long NiMh's will last is proportional to the relative mAh's of the batteries.
bonghitwillie previously reported being able to go up to 10+ hours on a set of 2650 duracells and said that 7.5 hours is never a problem.
This should mean that the 2000mAh Eneloops should easily go (2000/2620) X 7.5 = 5.67 hours and probably would do as much as (2000/2650) x 10 hours = 7.5 hours.
My own experience using 4 of them in an external battery pack for a MT 24/96 (with a new, fully charged battery that only lasts 2.25 hours without an external pack)) and recording for 10 hours indicates to me that they should last well over 5 hours in an R-09.
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On request I could charge up some Eneloops, test in an R-09 and report back in a day or so. However (someone correct me if I am wrong) I think how long NiMh's will last is proportional to the relative mAh's of the batteries.
typically yeah, but with the different discharge method they may render themselves useless at a different rate. Normal nimh batteries have a pretty steady output until they just plain die... these I'm skeptical of such that they may work more like the 9V rechargeables and their output rather quickly drops below 9V, even though they're holding %75 of a charge.
I ordered a set anyway, I'll test them out whenever they show up. I got a set of non-ultra-low batteries too for good measure in case they're not so great.
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I'm guessing you'll find they work fine based on 4 of them powering my MT 24/96 (with fully charged internal) for 10 hours. Let us know what you find out.
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Went with the Maha/Powerex Imedion 2100 mAhr low discharge batts & Maha charger and I'm very pleased so far. A week or so ago I voltage tested 4 standard 2600 mAhr rechargeables that I charged a few days after the Imedions 3-1/2 weeks prior. The Imedions were full and ready, the standard NiMH were nearly dead.
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I too have to make sure that my 7.2v 3000 x 3(9000mah) packs(the HIGH DISCHARGE ones) are ALWAYS charged the day of the show, or as close as I can get to that for festies. Otherwise, like you folks have said, my 7.2v 9000mah NIMH packs go DEAD pretty quickly. However, as long as I use them within a few days of charging them, they hold a charge pretty well. Id say after charging them and letting them sit for around 3-4 days, they still have around a 90% charge :) However, after a week or two, theyre pretty much KICKED and ready for anotehr charge.
The ebenfit f NIMH over Lion to me is the quicker charging times(I can recharge a 7.2v 3000mah NIMH battery in about 1 hour as long as its not DEAD) and their reliability. I have had (3) 7xx series lions DIE after 2 years. 2 of them died OUT OF THE BLUE within a month or 2 of purchasing them(one was GENUINE SONY and the other was a GENERIC SONY). It took 2 years for the 3rd one to die, but they give NO WARNINGS. You get to teh show and power the 722 on and BAM, NOTHING. I ALWAYS had to carry a backup lion w/ me :P Now I ONLY have ONE (1) 6000mah+ Lion left, and 2 smaller mah capacity lions left. I MUCH RATHER prefer the NIMH's for their reliability and quicker charging times ;)
I am DEFINITELY going to look into the low-discharge NIMH's for my 7.2v 7xx series setup tho :) I would LOVE to have my batts charges last more than a frickin week :P Does anyone know if they even make 7.2v 4500mah NIMH batts in a LOW-DISCHARGE version ??? I am moving up to the 7.2v 4500mah NIMH batts so I can cut WAY DOWN on weight. I now have 3 x 3000mah batts wired in parallel to give me 7.2v/9000mah 'packs', but with teh always changing market of batteries and electronics, I can now get (2) x 4500mah 7.2v NIMH batts to give me the SAME mah rating as the (3) batts Im using now :) Id LOVE to cut down on one battery per 'pack' to help my back out :) I should be able to afford the switch this fall for sure :) It will also help recharging at festies FOR SURE, since Id only have to recharge 2 batteries instead of 3 :) And since I have (2) of those blue "Chun" Smart Chargers, it will work out PERFECTLY ;D
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Hey Bean,
The only disadvantage I can see for the low self discharge NiMH is a slightly less total Ah rating. For me not worrying about having a full charge for a month (or more but that's enough for me) is well worth the trade off. I haven't looked for formats other than standard size (AAA, AA, C, D, etc) so I can't help you there. One of the other guys may know or you might check a battery supply place or website.
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I use a lot of AA and AAA batteries and certainly endorse the low discharge cells of both Sanyo and Powerex. They hold better than their advertised charge and hold their chemistry well.
I've used straight 2500 sanyo cells and 2700ma nimh powerex cells and they both have dropped total voltage over a period of less than six months. One of the powerex cells died completely and the MAHA MH-C9000 Advanced Battery Charger isn't able to revive it. In fact I've had two of those cells go bad...
The slow discharge cells that have been in service for almost a year (42 batteries total), they all still hold better than rated value. Highly recommended...
Also like and use the MaHa MH401, C9000, and C808m which charges/rejuvinates AA. AAA. C, and D cells. For 9volt we're using ipower lithium rechargables and after six months of heavy use, they're still performing like new. Good time to be investing in rechargable batteries.
Best,
John