[Closed] AA Ni-Mh batteries against single use batteries.

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[quote=2002 ]do not get any where near the run time the box said for the lights.

That may not have anything to do with what sort of batteries you use 😉

See table posted above - modern NiMH typically have higher capacity than alkalines, though it does depend on the discharge rate - alkaline are better at low discharge rates, at 50mA you're likely to see a significant increase in capacity.

Plus in very cold weather are single use ones better.

I don't think there's much to choose between alkaline and NiMH. Lithium are far better than either in the cold though - but pricy.

Thats a handy wee graph up there. I've always thought it was odd that makers of single use batteries don't have to give any comparable 'quantity' for capacity. We're left to try and guess based on some sort of heirarchy of superlatives - extra/ultra/plus/pro. Its interesting that what ever order they put the words 'pro, power, ultra and plus' Duracell can't make a battery with more oomph than bog standard Ikea own brand. The same guy did another graph comparing price per mAhr which is an eye opener too

with Nimh its also worth considering 'memory'. Cells can 'remember' how they discharge, so it is always worth running them to flat at full capacity every time, or they will start to flake out early.

http://singletrackworld.com/forum/topic/bullshit-that-has-become-true-through-repetition

You're more likely to harm cells if you run them to flat.

depends a lot on how good the rechargables are and what. charger you are using ,older chargers may not fully charge higher capacity cells.,
what does it say on the box

Got some of the eneloop batteries last autumn to run in the helmet lights, quite impressed by them actually. Buying 20 of them in one hit meant they weren't much more expensive than "standard" rechargeables. Performance so far is slightly better. (Charge time and run time)

IIRC battery capacity is measured at 20 degrees, dropping to 0 will (approximately) half the capacity of the battery and reduce it's power as well (depending on chemistry).

For long road rides I use the Energizer lithium batteries - they're not too expensive from places like 7dayshop. They give great runtimes, and are also very light at 15g per battery. Apparently they have a higher voltage than other AA's (maybe around 1.6v) and I think that can cause some lights to have problems with them - my Philips light's battery status indicator LEDs don't work with lithiums, but then the battery handling of Philips lights is a bit weird anyhow.

For rechargeable batteries I use Sanyo Eneloop Pro - I think they're around 2500mAh, and they have decent shelf-life, and give good runtimes in lights.

I use Uniross Rechargeable Hybrio NiMh 2400 series, in my Garmin Dakota. 20hrs+ with constant map display & plenty backlight, better than fresh Duracell Alkalines.

3rd vote for Sanyo eneloops; they seem to hold their charge for a good while. I think mine are about 4 years old too.

I use loads of AA's for my speedlights for my photography. I pretty much only use Eneloops or on the odd occaision the new 2900mah 7dayshop ones.

Depending on what the load is on the battery can affect the performance, for example this is a duracell battery

– 2348 mAh at 0.1A load
– 1808 mAh at 0.2A load
– 1050 mAh at 0.5A load
– 506 mAh at 1.0A load

Whereas a 2550 XX Eneloop will do...

– 2452 mAh at 0.2A load
– 2423 mAh at 0.5A load
– 2385 mAh at 1.0A load
– 2200 mAh at 2.0A load

HUGE difference.

i thought that 'memory effect' only affected nicd batteries, i could be wrong though.

Enloops are fantastic. If you're using alkaline or standard recharges, they are massively temperature sensitive and the cold really does reduce their effective capacity.

I've got some Duracell rechargeables that are like the Eneloops in that they maintain their charge much better than traditional rechargeable batteries.

I use them in my rear lights and they do a great job; last for ages.

martymac - Member

i thought that 'memory effect' only affected nicd batteries, i could be wrong though.

Yeah, I thought that NiMh were the first rechargeable battery type that could be charged anywhere within it's discharge cycle and didn't develop a memory effect.
NiCads were the ones that you had to be careful with.

[quote=martymac ]i thought that 'memory effect' only affected nicd batteries, i could be wrong though.

Probably, but then in real life it's a myth for those as well. It only happens if you discharge and recharge [b]exactly [/b]the same amount loads of times (ie in a space ship with solar panels experiencing day/night cycles, which is the only place it's ever been recorded in normal use AFAIK), which doesn't happen for most people's normal use. What people attribute to the "memory effect" tends to be damage due to over discharge or similar - hence the idea that it also happens with other battery chemistries.

In any case it's not worth worrying about whatever chemistry you're using, and as I pointed out above the usual advice to completely discharge is actually the opposite of what you should do to look after your batteries. Fully discharging batteries in series in something like a light which will take them to zero volts will likely result in reverse voltage in one or more cells which is very harmful. Far better to recharge before fully discharging, and indeed to stop charging before full charge.

I need to buy more eneloops I reckon, although the 7dayshop versions seem to be OK too

Where the cheapest place for eneloops in bulk? Might stick them on a christmas list

Also impressed at the Ikea alkalines, very impressed. I'll buy a whole load next time I'm there (plus some chocolate, salami and blue bags for smelly/wet/dirty kit)

Probably, but then in real life it's a myth for those as well. It only happens if you discharge and recharge exactly the same amount loads of times (ie in a space ship with solar panels experiencing day/night cycles, which is the only place it's ever been recorded in normal use AFAIK)

They've also stopped going empty=>full=>empty=>full on the charge/discharge cycle.
You can get much better life (10-12 years or more, instead of 6 or 7) by going from 50% ish up to about 95%. Instead of "as low as it can go and still work" to 100%, which is what most of the early hybrids did.

Its interesting that what ever order they put the words 'pro, power, ultra and plus' Duracell can't make a battery with more oomph than bog standard Ikea own brand

I was in Ikea last night, saw a big pack of their (pretty cheap) batteries and thought "nah, I bet they're rubbish, I'll get some Duracells". Might go back tonight...

No-one feels a bit bad about buying shitloads of single use batteries to simply chuck away after a few hours?

molgrips...yeah, I tend to favour rechargeables for just that reason. Seems very wasteful to sling batteries in the bin once they are dead because you can't recharge them.

When looking for lights to clip onto body or rucksack; there are loads of great ones but most use cr2032 batteries, and when you look at buying in bulk you realise how wasteful it is

I use alkalines for things that sit there, clocks n stuff.
Decent rechargeable for anything high load.

Wonder how old those test results are. I used to use and really rate Ikea batteries, they always seemed to last longer than Duracell's etc. But then they seemed to change spec/manufacturer or something as they really went downhill. That was a few years ago, haven't used them since. Might be worth a try again if that data is relatively recent.

[quote=mark90 ]Wonder how old those test results are.

Let me google image search that for you:
http://www.batteryshowdown.com/ - suggests it's from 2012