Rechargeable battery life: B&M Ixon IQ Speed

[peterh11]

I've noticed that I am not getting anywhere near the quoted lifetime on a single charge with the B&M Ixon IQ Speed. When the battery pack is fully charged it is supposed to give up to 10 hours on high beam. Now, I don't expect quite that much, but recently I find it gives barely 2 hours. I have had the light a bit over a year, though I have not used it very much - just for occasional evening rides.

When I run the battery down (lamp gives flashing red on the indicator LED) then recharge, it only takes 1.25 hours before the charger thinks it is fully charged. I reckon that's about 25% charged (consistent with above). I plugged my charger into a friend's partly run down identical battery pack, and that ran for somewhere around 3-4 hours before declaring it fully charged. So I am pretty sure it is the battery pack, not the charger.

Anyone else experienced this? I haven't stored it discharged - I made sure to charge it up a couple of times over the summer, though I was hardly using it then. I'm trying cycling it a few times (charge-discharge). I will also try just leaving it connected to the charger for 24 hours or so.

It's a good headlamp when it's working, but I obviously have to do something about the battery life. On a ride a couple of days ago it decided the battery was low and switched into low beam about half an hour before I got home - I was glad I was with a friend who had a good bright light until we got into town.

The answer is probably "new battery pack" but if anyone has any advice about rescuing this one that would be good.

PeterH

[fossil]

The battery might have developed a memory ?
I have a B&M Ixon and I always let it run down over night before recharging , even the morning after it still has light projecting 5 foot to the wall .

[robc02]

I have tried various types of rechargeable battery over the years and consistently failed to achieve adequate performance from them. Generally you have to care for them lovingly (a rechargeable battery is for life, not just for Christmas ) to stand a chance of them performing as specified. As you have realised and tried to address, a big problem for most bike lights is the summer when you don't need them, so they tend to sit in a cupboard not being used. Some modern types are alleged to be less fussy in this respect and are also alleged to be more tolerant of repeated partial discharging.

I gave up on them for cycle lighting several years ago, but am still blighted by them in my mobile phone where they are invariably "flat" when I need them, or claim to be OK until half way through my call .

Apparently you can sometimes improve the performance of a failing battery by fully discharging and recharging it as you have done - but I have never achieved much improvement this way. Worth a try, though - see the link below before overdoing it.

I believe you have a 5 cell Nickel–metal hydride battery, there is some information [url=http://en.wikipedia.org/wiki/Nickel–metal_hydride_battery]here[/url], which emphasises the need to charge them with care (don't overcharge) and the damage that can be caused by deep discharging them. Each cell in a battery will have slightly different characteristics so just one or two of them could be damaged by an over discharge. (This happened to me - but with NiCads).

You seem to have attempted to avoid the usual pitfalls but have still been caught out, just as I was - several times!

My solution was not another new battery, but a hub dynamo - and it has never let me down.

EDIT: Don't know why the embedded Wikipedia link didn't work! For the sake of clarity, here it is again:

http://en.wikipedia.org/wiki/Nickel–metal_hydride_battery

[peterh11]

Thanks fossil, I think I will take to doing that maybe not every time but at least every couple of months, including over the summer.

And robco2, thanks for your reply: yes, I too am a fan of hub dynamos and all the other bikes in our household have them, with B&M IQ Cyo headlights. However, these are all commuting bikes where utility and having light available at all times was the priority. In this case I wanted a high power light I could put on my touring bike (or a different bike) when and only when I needed it, without hassle or spending the money to have my front wheel rebuilt, which I now understand was a bit naive!

This experience could drive me to getting another front wheel built up with a Schmidt hub, which I can use in the winter, or if anyone wants to sell me a second hand one for a reasonable price I could be open that

On a more positive note, the battery charged for 2 hours yesterday evening before the charger lit its green "finished charging" indicator. I'm leaving it for a full 24 hours anyway, hoping that the charger will continue to supply a trickle current (not easy to measure that without making up some extra leads). Then I'll give it another cycle and see if the improvement continues.

PeterH

[sjs]

There's a lot to be said for lights (and other gadgets) which can use rechargeable AAs. Then it's easy to swap duff batteries for new ones, easy to swap discharged ones for fresh ones, and easy to use a smart charger which protects the batteries and tells you when they're on their last legs.

[james01]

There's a lot to be said for lights (and other gadgets) which can use rechargeable AAs. .

I agree. And in an emergency you can even buy ordinary disposables at a filling station. However, best of all is to remove battery angst and fit a dynamo

[robc02]

There's a lot to be said for lights (and other gadgets) which can use rechargeable AAs. .

I agree. And in an emergency you can even buy ordinary disposables at a filling station. However, best of all is to remove battery angst and fit a dynamo

Yes to rechargeable/disposable AAs, especially if the item is to be used intermittently and/or not receive meticulous attention to charging/discharging.

[meic]

Another possibility is that your batteries are being affected by the cold.

NiMH are not very good at delivering power at low temperatures I had a lot of trouble last year with this problem. My Ixon IQ (not speed) kept dropping down to low power mode as the light thought they were expired due to the low output but they still had the full capacity in them at lower power rates.
So like in your case the battery "expired" out on the road and only accepted a 20% charge back at home.

[andrew_s]

The FAQ section on the B+M Ixon IQ Speed page says that the battery pack is 4xAA NiMh.
(google translate seems to cope reasonably)

Experience with sets of 4xAA in other situations would lead me to guess that one of the 4 cells is dead, or nearly so.
A new pack of 4 ought to be all the same, but it isn't that unusual for one of a set to be weaker than the others. It will generally recover if charged and discharged on its own 3-5 times, but if just used from new in a light with a charger that's charging all 4 cells together, it doesn't get the chance.
Discharging an NiMh cell much below 1V damages it, so the red light will be set to come on at 4V (ish). If the weak cell had half the initial capacity of the other three, 4V won't be reached until the bad cell is down to 0.5V, with the 3 half discharged cells just below the 1.2V nominal. You then recharge all 4 together, but the 3 half discharged cells charge up fully and stop the charging before the weak cell is fully charged. Go back to the beginning, with the weak cell in worse condition than it was before.

Ideally, you'd get a new set of 4xAA rechargeables, and get them started with a charger that both deals with cells individually rather than as pairs, and has a discharge function.
The BL700 is most popular, the MH-C9000 is better but costs more, the 7dayshop 600LCD or 808LCD are cheap but I've no reports on them.
The first two chargers report actual cell capacity, but I'd guess that with the 7dayshop ones it would be up to you to spot the charge finishing at the same time (ish) for all 4.
It would probably be a good idea to take the 4xAA out and charge them in your separate charger once in a while (once in every half dozen charges?), to stop capacity differences growing in the same way.

[meic]

I think you (or Google translator ) have made a mistake there. The Ixon IQ uses the 4AA batteries and the answer is comparing that to the Ixon IQ Speed's 6V pack.

It is a problem with B&M's lighting system's names that you have to keep your eyes peeled for every letter (or lack of letters) all the time.

[peterh11]

I think you (or Google translator ) have made a mistake there. The Ixon IQ uses the 4AA batteries and the answer is comparing that to the Ixon IQ Speed's 6V pack.

It is a problem with B&M's lighting system's names that you have to keep your eyes peeled for every letter (or lack of letters) all the time.

Actually, the "Ixon IQ Speed" uses a custom battery pack made up of FIVE 1.2V NiMH batteries with 4Ah capacity, these are somewhat larger than AA. I attach a picture (assuming I got it right).

I have considered building a pack out of 5 AAs as well, where I can easily replace any or all, that is an option. But as has been commented, the fundamental issue seems to be rechargeable batteries in occasional use - we don't have this problem with phones in our household as they get discharged and recharged a couple of times every week.

I guess I'm going to live with this or get a hub dynamo, and justify it as a long term investment.

Thanks all.

PeterH

[Phil_Lee]

I don't think it's necessarily the occasional use, provided they are stored correctly and charged occasionally.
The bigger problem is the fact that the cells are pre-assembled into packs, and charged in series rather than individually.
The solution is to make up a 5 cell holder and use separate cells in it, so each cell can be charged to suit it's own requirements, which both helps prevent a weak cell developing, and allows one to be replaced individually if it does.
With some sensible design, packs can be daisy chained in parallel to give extra capacity if 6v 2AH is insufficient (you can have nearly 3AH from AA cells, but not in low-self-discharge form).
A switched bridge wire can be fitted past one holder in each pack of 5 to allow 4 alkalines to be used instead of 5 NiMH should the need arise.

Oh, and +1 on the MH-C9000. Excellent charger/analyser.

[Richard D]

How tricky would it be to make a holder for 5 standard AAs, and connect the Ixon IQ Speed to that?

I'm sorely tempted by a new front light. I don't want to go down the route of having a dynamo on my road wheel, nor do I want one of those "blind everyone for 0.5 miles" LED lamps that are the fashion, and a couple of hours of googling and reading reviews suggests that the Ixon IQ Speed Premium has a decent light output, a decent running time and a great beam pattern. But the included battery pack clearly sucks. A li-ion battery pack would be better, but you muck about making up your own at your peril (it's a great way to start a fire). The solution would be some sort of plastic holder into which standard AA cells can be fitted - ideally Enloops (some versions of which are also better at low temperatures than "standard" NiMHs). Plus I already have LOTS of Eneloops and the obligatory MH-C9000 charger.

[SA_SA_SA]

The memory effect is almost a myth:
it was documented as occuring on satellites where a computer ran the battery down exactly the same amount before topping up the partially discharged battery: it was fixed by introducing a bit of randomness I think.

Batterys left trickle charging may see slight voltage depression (just about 0.1V) apparently.

[Richard D]

I don't care much about "memory effect". As a myth it was mostly promulgated because cells were charged in ways which damaging them, rather than the cells acquiring a "memory". These days, most of the chargers available are smart enough not to do that. Though it clearly is harder to charge a "battery" of cells properly than individual cells, which might well be the cause of some of the charging problems attributed to the B&M Ixon IQ Speed - one duff cell in the battery is going to cause havoc.

But there are two more significant - and easily demonstrable - issues with NiMH battery chemistry. The first is the poor performance at low temperatures; I'd prefer it to be warm and sunny every time I ride, but that's not going to be the case during winter months. And secondly the self-discharge characteristics of most NiMHs are grim; charge it one week, leave it on a shelf, next week you could be looking at a battery pack down below 70%; leave it a month and it could be almost flat. Low self-discharge characteristic NiMHs are available - the famed Sanyo Eneloop cells are such - but I'm prepared to bet that B&M haven't specified such cells when making up their own 5-cell packages. And it's the self-discharge characteristics that some posters have issues with (presumably becuase it sucks to reach for a freshly-charged battery pack that's been sat on the shelf for a month only to find that the darned thing is flat; doesn't happen with anything with a lithium-based battery in it -which is most rechargeable items these days).

The more I think about it - and the more I read about the Ixon IQ Speed - the more I think that putting together my own 5-cell package of Eneloops would be pretty straightforward.