Bike lights batteries

biggiesmalls

I got some new bike lights last year - a Blackburn Phaser front light which is pretty bright, I'm very happy with it. Just started using lights again in the evenings and I noticed they're running down very very quickly. Is it a battery problem or is there some reason the lights might be drawing extra power? I was using disposables, switched to rechargeables so could that be it?

I got a few packets of NiMH 1.2v / 2650 mA AA batteries that were on offer last year. Made by JCB (yes the digger company), but what the hell. They were ok last winter I think, but this week I've had to recharge every night. This evening, the lights were normal brightness when I left work; 20 minutes later, noticeably dimmer; and 45 minutes when I got home, just barely visible. Definitely worse than a few months ago. I switched to a fresh unused packet (also JCB...) and charged them overnight -- same result. I'm trying some Eneloops (1900mA) I dug out of a camera to see what happens tomorrow evening.

What do people reckon- is it the batteries, or is it maybe the light? Am I going to have to go back to throw-aways?

Cheers

corshamjim

Rechargeables do tend to drop off very quickly when they run out compared with ordinary batteries. It's worth buying a good brand as the cheapest sometimes are rather rubbish. I know its not cheap but if you use rechargeables a lot then this device is really great for checking capacity and making sure you get the best out of them. http://mobile.maplin.co.uk/module.aspx?moduleno=217893

Kieran_Burns

It's that charger again: http://www.batterylogic.co.uk/technolin ... -BL700.asp

If you run the refresh cycle on this for each battery, it maximises the capacity available. Basically it fully discharges and charges the batteries until they can gain no more capacity. It really does work - takes AGES though!

small_bloke

Here is recent report done by Which Magazine
Top 3 rechargeable batteries in order.

These are AA batteries.

1. Ansmann Digital 2,850mAh (price £9 for 4)
2. Maplin Extra-High Capacity N05BW 2,500mAh (price £13 for 4)
3. Uniross 2400 Series Premium Hybrio (price £15 for 4)

biggiesmalls

Thanks for the replies

I think I don't need a battery tester, just some decent batteries... serves me right for being a cheapo I suppose I got a pack of AA and AAA both for under a tenner . At least they'll be ok for remotes/etc around the house

Just frustrating that they can get away with this sort of crap- they should be what they're labelled as. It says a voltage and a capacity so I don't get why one brand vs another should be so different.Thanks for the Which magazine tip by the way -- always good to have a side by side technical comparison of this kind of thing - the brand/design doesn't matter in itself but the performance at the end is everything

The eneloops were from a camera but I did recharge them fully before sticking them in the lights; will test it tonight (or just leave it on while i do stuff, see what happens to the brightness)

desweller

The sophistication of the charger is important. If it's not fully charging your cells then it doesn't matter what brand they are.

davis

Aye.
Get a decent charger.
Get a decent charger.
Get a decent charger.

(just buy the one Kieran linked to). Get it to to do the battery conditioning thingy. Then think about your batteries...

jejv

davis wrote:

Aye.
Get a decent charger.
Get a decent charger.
Get a decent charger.

(just buy the one Kieran linked to). Get it to to do the battery conditioning thingy. Then think about your batteries...

Meh. I've been telling y'all for years that you can get that cheaper elsewhere. Ya must be loaded.
http://www.conrad-uk.com/ce/en/product/ ... Detail=005

http://www.candlepowerforums.com/vb/sho ... -europeans

Then if you nose around candlepower forums, opinions of that are mixed - safety problems.

DesWeller wrote:

The sophistication of the charger is important. If it's not fully charging your cells then it doesn't matter what brand they are.

Yes, but not quite. The problem is poor chargers - such as Ansmann [sic] - may overcharge your cells, which is bad for lifetime & capacity.
Not much sophistication is needed - just a bit of care in the design, and priority of engineering over marketing.

small_bloke wrote:

Here is recent report done by Which Magazine

I'd trust the folk on candlepower forums more than Which?

oxoman wrote:

I personally suspect the JCB's are naff. At the end of the day they are just badged up junk from china.

Maybe, but we have some no-brand batteries that actually quite good. Keep their capacity over the years.
JCB don't make batteries, but neither do Ansmann, AFAICT.
Saw some decently spec'ed no-brand C-cells, rang up the sellers and asked for a data sheet. Data sheet turned up! Bought batteries. Batteries fine.

GP Recyko seems to be a similar level of technology to Sanyo Eneloop, slightly lower voltage under load, slightly higher capacity, usually a lot cheaper. That's what I'd go for.
Unless you are cycling the batteries every week, I suspect that the low-self-discharge batteries such as Eneloop or Recyko are a better bet than higher capacity conventional NiMH batteries. I've found the high-capacity conventional NiMH cells lose capacity fast if abused (run flat & left flat), while the low self-discharge batteries seem quite tough, and hold their capacity.

Sanyo have a new higher capacity ("2500mAh" AA) low-self-discharge technology, but the rated cycles are lower. Might be worth checking what Candlepower forums think of that, but unless price is falling fast, GP Recyko still seems like a good bet for me.

http://www.candlepowerforums.com/vb/sho ... c34c21edb4

Charger : Maha C9000
[like corshamjim says]
Only problem - for me - is default charge current for AAA's is too high 1Amp, should be 400-500mA for better cell life. So not necessarily for numpties.