advice needed on fitting a lumotec oval plus

davek said:

The Nexus dynamo has positive and negative terminals marked, but there
are no corresponding markings on the Lumotec Oval Plus lamp - does it
matter which way round I connect it? The instructions are not
forthcoming on this matter.

I don't know the lamp, but one of the terminals on the Nexus is also
earthed. If one of the terminals on the lamp is earthed too, then it
does matter. I'm running a Basta lamp off my Nexus - it only needs on
wire to work (though it's usually a good idea to connect the earths
together anyway).

--
Andrew

davek said:

The Nexus dynamo has positive and negative terminals marked, but there
are no corresponding markings on the Lumotec Oval Plus lamp - does it
matter which way round I connect it? The instructions are not
forthcoming on this matter.

Treat the one marked supply as positive, and the one marked ground as
negative.
Ground is sometimes a triangle of parallel lines, the shortest at the
bottom.

However, I doubt it matters, AFAIK, the generator is an AC device.

Quoted message said:

One other question: if I am running the dynamo to a front lamp only
(ie no rear lamp) do I need to upgrade the bulb from 2.4W to 3W? I
know upgrading is an /option/, but is it actually /necessary/?

Yes, or you will blow the blub first time you ride above "very slow".
The output of the generator is designed to supply a 3W drain, being a 2.4W
front and a 0.6W rear. The design specification of the generator will be to
the German standard which requires full lighting power at quite low speeds.

- Nigel

--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/

Nigel Cliffe said:

Yes, or you will blow the blub first time you ride above "very slow".

Argh! That's exactly what I feared. Unfortunately, they didn't have any
3W bulbs in stock (at Bikefix) so I shall have to make another shopping
trip tomorrow before it gets dark...

d.

Naqerj said:

I don't know the lamp, but one of the terminals on the Nexus is also
earthed.

Damn - did I say Nexus? I meant Nordlicht, as in bottle generator... I
was looking at the Nexus hub dynamo but can't really afford it at the
moment, even though the Bikefix offer of a complete Nexus equipped wheel
for £95 seemed like a pretty good price to me. :-(

While I was in Bikefix, I also spent some time covetously admiring the
Taifun in the window, not to mention the Grasshopper next to it. Oooh!

d.

Nigel Cliffe said:

davek wrote:

<snip>

Quoted message said:

Quoted message said:

One other question: if I am running the dynamo to a front lamp only
(ie no rear lamp) do I need to upgrade the bulb from 2.4W to 3W? I
know upgrading is an /option/, but is it actually /necessary/?

Yes, or you will blow the blub first time you ride above "very slow".
The output of the generator is designed to supply a 3W drain, being a 2.4W
front and a 0.6W rear. The design specification of the generator will be to
the German standard which requires full lighting power at quite low speeds.

You sure? I've been running a lumotech front (LED rear so nowt) on a
Nordlich fine. The reason being they are Zener protected, I thought.

"davek" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Naqerj said:

I don't know the lamp, but one of the terminals on the Nexus is also
earthed.

Damn - did I say Nexus? I meant Nordlicht, as in bottle generator... I was
looking at the Nexus hub dynamo but can't really afford it at the moment,
even though the Bikefix offer of a complete Nexus equipped wheel for £95
seemed like a pretty good price to me. :-(

While I was in Bikefix, I also spent some time covetously admiring the
Taifun in the window, not to mention the Grasshopper next to it. Oooh!

d.

I rode that Taifun, very tempting!

davek said:

One other question: if I am running the dynamo to a front lamp only (ie
no rear lamp) do I need to upgrade the bulb from 2.4W to 3W? I know
upgrading is an /option/, but is it actually /necessary/?

You wil either need (and want) a high wattage bulb or (better)
a regulator/limiter.

BugBear

Tosspot said:

You sure? I've been running a lumotech front (LED rear so nowt) on a

Quoted message said:

Nordlich fine. The reason being they are Zener protected, I thought.

How much protection does it offer? I assume it is still possible - in
theory, at least - to overload the 2.4W front lamp, right? If you went
/really/ fast?

I'm going to try to get hold of a 3W lamp anyway - although I went out
for a test ride after fitting the Lumotec last night and was pretty
impressed with how well the 2.4W lamp lit the road ahead of me. And the
standlight stayed on for /ages/ afterwards. It's brilliant. Literally.

I'll have to try it on a really dark road to see how badly I need that
3W lamp - or I could just connect up the rear lamp that is built into
the reflector on the mudguard. But since I have two Cateye AU100s on
the rear already, I think that might be overkill...

Just out of interest, what would happen if I installed, say, a 5W lamp?
(Electronics is not my strong subject, in case you couldn't guess.)

d.

In article said:

I'll have to try it on a really dark road to see how badly I need that
3W lamp - or I could just connect up the rear lamp that is built into
the reflector on the mudguard. But since I have two Cateye AU100s on
the rear already, I think that might be overkill...

Just out of interest, what would happen if I installed, say, a 5W lamp?
(Electronics is not my strong subject, in case you couldn't guess.)

If you installed a suitable 5W lamp, then in principle you would get
more light but have to work harder, but, at least in wet weather, the
dynamo would probably slip under the extra load unless you are using a
hub dynamo. But at low speed you would get less light than from a 3W,
because bulbs are less efficient when under-driven.

So the usual answer is to use an additional 3W bulb in series, and a
switch to short it out so at low speed you only use one bulb.
http://www.peterwhitecycles.com/dualsetupfork.htm
http://www.m-gineering.nl/sondualg.htm

("Suitable" here means "designed to work on the same 0.5A current", so
change the 3W 6V bulb for a 5W 10V bulb. If such a thing exists.
The 2.4W bulb is designed to work with 4.8V across it, and 1.2V
across the 0.6W rear bulb. But because dynamos are only _roughly_
constant current devices, you could get 3V across it and a higher
current, rather than just keep the same 0.5A at 2.4V total, which is
why you risk blowing it.)

LSMike said:

I rode that Taifun, very tempting!

Yes, I remember you mentioning it. Very envious.

I also rather like the look of the Airnimal White Rhino they had on
display. Now that's what I call a folding bike!

d.

"davek" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

LSMike said:

I rode that Taifun, very tempting!

Yes, I remember you mentioning it. Very envious.

If it had been in the right colour or a Fujin I'd probably have whipped the
credit card out the pocket so fast it'd have bounced off the wall behind the
counter. 😉

Quoted message said:

I also rather like the look of the Airnimal White Rhino they had on
display. Now that's what I call a folding bike!

d.

Ooh, that is another nice bike! I didn't notice it at the time, after all
mine eyes are for the dark side now.

davek said:

Tosspot said:

You sure? I've been running a lumotech front (LED rear so nowt) on a

Quoted message said:

Nordlich fine. The reason being they are Zener protected, I thought.

How much protection does it offer? I assume it is still possible - in
theory, at least - to overload the 2.4W front lamp, right? If you went
/really/ fast?

Weellll, about 30mph, so not super fast.

Quoted message said:

I'm going to try to get hold of a 3W lamp anyway - although I went out
for a test ride after fitting the Lumotec last night and was pretty
impressed with how well the 2.4W lamp lit the road ahead of me. And the
standlight stayed on for /ages/ afterwards. It's brilliant. Literally.

Yep. Thats the setup, the LED rear has a standlight for me as well.
Out of interest, is your front standlight orange?

Quoted message said:

I'll have to try it on a really dark road to see how badly I need that
3W lamp - or I could just connect up the rear lamp that is built into
the reflector on the mudguard. But since I have two Cateye AU100s on
the rear already, I think that might be overkill...

Just out of interest, what would happen if I installed, say, a 5W lamp?
(Electronics is not my strong subject, in case you couldn't guess.)

You'd need to go faster? But I seem to recall dynamos are geared for
particular speeds, there was a great site somewhere, I'll google later.

Tosspot said:

Nigel Cliffe said:

davek wrote:

<snip>

Quoted message said:

Quoted message said:

One other question: if I am running the dynamo to a front lamp only
(ie no rear lamp) do I need to upgrade the bulb from 2.4W to 3W? I
know upgrading is an /option/, but is it actually /necessary/?

Yes, or you will blow the blub first time you ride above "very slow".
The output of the generator is designed to supply a 3W drain, being
a 2.4W front and a 0.6W rear. The design specification of the
generator will be to the German standard which requires full
lighting power at quite low speeds.

You sure? I've been running a lumotech front (LED rear so nowt) on a
Nordlich fine. The reason being they are Zener protected, I thought.

Maker says the zener isn't meant to offer permenant protection in the event
of rear lamp failure, and continued use with a dead rear lamp could cause
the zener to fail. (At least it says that in the manual for the round lamp
and I'd expect the internal behaviour to be similar on both lamps; I have
examples of each type on different bikes).

A dynamo system offers the potential of high reliability, high availability
and low hassle, therefore deliberately going outside the maker's
recommendations seems to be inviting unnecessary troubles.

For what its worth, I find a 3W bulb (in a round lamp) is a bit brighter
than a 2.4W (in an oval lamp + B&M rear), though not by a huge margin. My
lamps have standlights and are driven from B&M bottle dynamos.

- Nigel

--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/

Alan Braggins said:

If you installed a suitable 5W lamp, then in principle you would get
more light but have to work harder <snip>

Thanks, Alan, that's great stuff. I managed to get a 3W lamp today
(after phoning round several LBSs, a few general electrical shops and
nearly every sodding branch of Evans) and it seems plenty bright (will
get the chance to test it properly on the ride home tomorrow night as
I'm due a late night), but I'm now tempted to try dabbling in the arcane
world of home-made lighting - like a /proper/ audaxer!

d.

Tosspot said:

Weellll, about 30mph, so not super fast.

That's not all that fast, is it. Though it might seem pretty fast if it
was dark enough to need the light... You can probably tell I haven't
ridden at night for some years.

Quoted message said:

Yep. Thats the setup, the LED rear has a standlight for me as well. Out
of interest, is your front standlight orange?

No, the standlight is bright white, with maybe a slight bluish tinge -
it makes the halogen lamp look decidedly yellow by comparison.

Quoted message said:

You'd need to go faster? But I seem to recall dynamos are geared for
particular speeds, there was a great site somewhere, I'll google later.

Cheers - but I think Alan has answered the question so don't go to any
trouble.

d.

in message <[email hidden]>, davek

(') said:

The Nexus dynamo has positive and negative terminals marked, but there
are no corresponding markings on the Lumotec Oval Plus lamp - does it
matter which way round I connect it? The instructions are not
forthcoming on this matter.

A dynamo by definition generates AC, so no, it doesn't.

Quoted message said:

One other question: if I am running the dynamo to a front lamp only
(ie no rear lamp) do I need to upgrade the bulb from 2.4W to 3W? I
know upgrading is an /option/, but is it actually /necessary/?

No, it isn't. My partner has a Nexus driving a front light only, with a
2.4 watt bulb. It hasn't come to any harm.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
;; We don't just borrow words; on occasion, English has pursued other
;; languages down alleyways to beat them unconscious and riffle their
;; pockets for new vocabulary -- James D. Nicoll

davek said:

Tosspot said:

Weellll, about 30mph, so not super fast.

That's not all that fast, is it. Though it might seem pretty fast if it
was dark enough to need the light... You can probably tell I haven't
ridden at night for some years.

I find anything above 20mph is *way* too fast at night if there are no
streetlights. However, this may be due to me being a puss...

Quoted message said:

Quoted message said:

Yep. Thats the setup, the LED rear has a standlight for me as well. Out
of interest, is your front standlight orange?

No, the standlight is bright white, with maybe a slight bluish tinge -
it makes the halogen lamp look decidedly yellow by comparison.

Certain (older) LED-standlight-equipped lights do have an orange tinge. My
Oval Plus has a blue-white LED like yours but the Hella light on my tourer
has an orange LED. Of the two, the Hella provides the best main beam which
is why I keep it.

Regards,

-david

davek said:

The Nexus dynamo has positive and negative terminals marked, but there
are no corresponding markings on the Lumotec Oval Plus lamp - does it
matter which way round I connect it? The instructions are not
forthcoming on this matter.

Quoted message said:

One other question: if I am running the dynamo to a front lamp only (ie
no rear lamp) do I need to upgrade the bulb from 2.4W to 3W? I know
upgrading is an /option/, but is it actually /necessary/?

Dynamos are AC sources, so positive and negative has little meaning
in this context; an AC source can be connected in reverse (but do
not try this with mains electricity - the live side of the circuit
must be switchable).

With a dynamo generator, it doesn't matter, apart from earthing,
but with two terminals I suspect it's not earthed. It shouldn't
matter which way round you make the connections, BICBW.

Simon

Tosspot said:

Nigel Cliffe said:

davek wrote:

<snip>

Quoted message said:

Quoted message said:

One other question: if I am running the dynamo to a front lamp only
(ie no rear lamp) do I need to upgrade the bulb from 2.4W to 3W? I
know upgrading is an /option/, but is it actually /necessary/?

Yes, or you will blow the blub first time you ride above "very slow".
The output of the generator is designed to supply a 3W drain, being a
2.4W front and a 0.6W rear. The design specification of the generator
will be to the German standard which requires full lighting power at
quite low speeds.

You sure? I've been running a lumotech front (LED rear so nowt) on a
Nordlich fine. The reason being they are Zener protected, I thought.

I suspect you will shorten the bulb life by doing that. You will
certainly get less light output than you would by using a 3W bulb,
and will be wasting approximately 0.6W in heating the Zener, which
may also shorten its life.

Simon