Review of New Bisun caving lamp - Great performance on a budget

adz

New member
I?ve been looking for a new caving lamp for a while, nothing wrong with the Bisun M2 I?ve used for the last two years, in fact it?s been bombproof but as people seem to be getting brighter and brighter lamps, I seemed to develop a bit of light envy!  Also the M2 really only has  one power level with a choice of either  spot or flood.

I really wanted a brighter light, with a couple of power  levels, including a low light that would run for ages if needed, a really bright  setting and a spot beam that would be used for erm... well, spotting stuff.

The problem is I?m mean (ask anyone who knows me.  Mean, they?ll say. ). So basically my budget was around the sub ?100 level (ok, around ?50 really, I know!)
I?ve looked at quite a few of the options and you can get some quite bright and apparently tough lights for the money.  One of the Fenix Head torches looked really good actually but the problem with them all was Durability and Beam pattern.

The advantage with a Bisun Lamp is you retrofit the Led reflector into an Oldham (or Oldham stylee) Lamp. The Oldham design,  I think is well proven for toughness and really needs no more comment than that. The two LED design that Bisun lamps use is important though. The flood is completely even and you can always see right into your periphery vision (seeing where you?re walking is always a plus) and with the options of slight beam blending (a bit of spot in the flood for instance) you get a great beam but without the hot spot that I find distracting (one of my main problems with the cheaper, bright lights). The Spot is nicely focused thanks to the design of the reflector.

Eventually I thought of contacting Bisun again to see what products they had. LED technology has moved on a lot in two years. However the Bisun line up didn?t have what I was looking for in my price range.  I fired off an email and Dave (of Bisun) got back to me with the option of testing a new 3 Level Lamp model that he was thinking of adding to the range, within my kind of budget.

I agreed and I have to say I?ve been really pleased with the result (if fact I?ve actually paid money for it, the highest endorsement a mean person can give really. Cheques in the post Dave.. really.)  Also a refreshing change for someone to listen to what you are after and the price range you?re thinking about and then just basically build it for you.

The lamp is on the bisun website www.bisun.co.uk, it?s called the R3, I think. 

The Lamp has 3 power settings;  a Low around 20 lumen, the Mid around 60 Lumen and the High about 155 lumen.

You can have the beams totally independent (all spot or all flood) or have a bit of beam blending or a lot of beam blending depending on where you place a jumper on the circuit board.

Fitting the reflector in the headset is really easy and the instructions on the website are easy to follow.

The lamp uses the original switch and operation is intuitive. Basically you switch through the power levels in one direction for the flood settings and the other direction for the spot settings.

My impressions on the light in use;

Flood - Regarding the power setting - the 'Low' is fine for general caving if you have to preserve battery power, that is to say, you can see stuff but its not bright. Its the pilot lamp essentially.
The 'Mid' setting felt about as bright as the M2 or brighter. Hard to tell, the point is that it's more than enough to cave all day on.
The 'High' setting is brilliant in flood mode, it feels like you?re taking daylight underground with you.

Spot - Settings - Same as above. The beam is a perfect shape and on the high setting is really impressive

Beam Blending - Ok, I started off with the jumper in (what I'll call) position two, that is with lots of beam blending. For me it was just too much. I found it distracting and felt that I needed more flood light (even though it was fine, your eyes are draw forward sort of thing)

Halfway into the trip I changed the jumper to position one. Immediately felt that was perfect mix, just right for me and felt like no wasted power. I think the spot beam giving the flood beam a bit of forward punch is really good. Also the spot beam was much better.

Regarding runtime, I did a test from fully charged to flat. 

From 3xAA Enloop 2500mah fully charged, brand new batteries.

I got 6 hours constant high power. The lamp then dropped into low setting for a further 2 ? to 3 hours before flickering and dimming away.

I haven?t tested the lamp on the other settings but clever people will be able to work it out from the power consumption.

Dave or the website can give you more information on power consumption and lumens and things like that.





 

jarvist

New member
The two LED design that Bisun lamps use is important though. The flood is completely even and you can always see right into your periphery vision (seeing where you?re walking is always a plus) and with the options of slight beam blending (a bit of spot in the flood for instance) you get a great beam but without the hot spot that I find distracting (one of my main problems with the cheaper, bright lights). The Spot is nicely focused thanks to the design of the reflector.

I think the twin reflector really is the key bonus of the Bisun design. A reflected spot is much more focused (or rather, collimated) than a lens like optic, especially with the new high efficiency XP-G LEDs. The blended beam of the Bisun makes it an excellent light to use underground, I've been using one as my caving light since a prototype back in 2004, and I now find using another light primitive by comparison (what? I can't leave the omni on and blip the spot separately when I want?).

I agree with the general power levels above; on my P51 I typically cave off the Omni on Medium sometimes blended with some Spot on Low, and crank up the Omni to appreciate a big bit of passage or chamber, and blip up the Spot to max to see what's going on up / down a pitch 40+m away. I did Stream at the weekend with someone else with a Bisun, who descended with the Spot on max. It was light having an anti-aircraft search light surveying the pitch, really cool way to appreciate the space we were in!

On ~medium I easily get a weekend out of a rechargeable battery pack, without having to worry about it.
When on expo & using flatcells, I dial my P51 right down - you need surprisingly few lumens to follow an SRT rope, crawl or do detailed work close up. Still great to be able to blip on the power to check out a window on a pitch though! I would happily do a 3day camping trip + a couple of 12hr bounce trips off a single disposable battery, I'm sure I could do even better if I wanted to, but that's more than good enough for me.
 

biff

New member
A nice little update to a nice module. Good work Dave.

For anyone who hasn't been around a while, the Bisun was basically the first pit lamp 'module' to incorporate high powered LEDs. When Dave built the first Bisun, I got a look at it, decided that it was rather good, and immediately shut down LED bulb production (which was a bonus as it got me my coffee table back ). Obviously the technology has moved on and as always Dave has kept right up with it. Top job. 

 

potholer

New member
To quite an extent, I was looking at simplifying the selection of the units I made, since I had a couple of models that overlapped somewhat in features.

The new unit is a real advance on both the two previous models (Z3 and M3) which it replaces, so I now have a range which is a bit easier to understand, with basic, mid-range and higher-end inserts for people with headlite/fx3, or other similar-voltage setups with mining lamp headsets.

As far as the spot beam goes, I see that some manufacturer has patented the idea of using half a reflector to give both a spot beam and downspill from a single LED.
However, since they only applied for the patent 5 years after I started making and selling my own units using that layout, I guess I'm fairly safe.
 

jarvist

New member
So what's the current lineup?

There's the P51 with the fully independently controllable twin beams.
The new R3 which only has one beam on at a time, but with three power levels, and the ability to bleed power from one to the other by setting a jumper in the headset.
And the S3 which works just like an FX3 bulb headset but with high power LEDs for both beam and spot.

Is that about right? Do all three use the split reflector / omni dual beam configuration?
Do all of them use the same modern XP-G R5 efficiency LEDs?

Do you know of any new LED advances expected soon at this ~1W power level, or is XP-G R5 as good as we're going to get for a few years?
 

jarvist

New member
So I went and did a bit of my own googling, and was excited to discover this press release from a couple of weeks ago:

http://www.cree.com/press/press_detail.asp?i=1288616204417

So now Cree is putting out LEDs with both high >100Lumen/Watt efficiency & high CRI (Colour Rendering Index)! This might finally put an end to the 'suicide light' complainers, and would probably be useful in a photography light too.

?Our high-CRI XLamp LEDs can deliver light quality comparable to halogen with better efficacy than fluorescents."

It will be interesting to see how much more expensive the CRI-80/85/90 LEDs are compared to the standard, as they become available from the usual suppliers.
 

potholer

New member
The standard pitlamp insert range is now the S3, R3, and P51m, and all use top-end XP-Gs and the same optical layout.
I doubt there'll be any huge leap in LED performance soon, at least in light-per-watt terms.

The high CRI thing was from 2010.
I'm not sure whether they'd be any better for cave use than the standard LEDs of appropriate colour, and there's a fair efficiency hit compared to simply using more neutral/warm regular LEDs.
 

biff

New member
potholer said:
since they only applied for the patent 5 years after I started making and selling my own units using that layout, I guess I'm fairly safe.

Dave. Your right not to loose sleep over it. They can no more patent it than you could as its already in the public domain (put there by you). They may have a poor patent agent who has let it slide through, so it would be of no value to them + it costs a fortune to maintain patents acroos the planet (just for the Chinese to ignore anyway). A patent for the most part is just a helpful design guide to allow someone to get round it, and I doubt it would be beyond the wit of reflector / optic manufacturers with computer modelling to design something that combines focus and spill in any possible profile that they desire anyway.

Have you got any more information on the patent you mention? It would be interesting to see what theyre up to. It might be that they have simply paid the get started fee so that they can stamp 'patent pending' on a product, a classic and none too classy manufacturer trick to make it look like they are onto someting clever. (Boycott any such products on principle  :))

As Im rambling, my basic take on patents and the little guy, is that you would have had to come up with a once in someone elses lifetime eureka moment, have some serious business savvy, and have a national lottery level of luck for it to ever do anything more than cost you coin.

Musing on, you could patent a tilt mechanism on the LED that points down into the reflector so you can vary the balance of light onto the reflector (for focus) and the amount missing the reflector (for flood) ------------- or at least you could have if this idea wasn't now in the public domain.
 

biff

New member
jarvist said:
or is XP-G R5 as good as we're going to get for a few years?

That might be the XM-Ls and also XP-G S2s (same sort of colour bins as the R5s), but Im splitting hairs.
 

potholer

New member
biff said:
Have you got any more information on the patent you mention? It would be interesting to see what theyre up to. It might be that they have simply paid the get started fee so that they can stamp 'patent pending' on a product, a classic and none too classy manufacturer trick to make it look like they are onto someting clever. (Boycott any such products on principle  :))
http://www.patentgenius.com/patent/7850348.html
About the only difference is that their LED is mounted on a case rather than a separate heatsink, but I guess it's hard to be greatly different when the only 'novelty' is the basic geometry, from which everything else follows - like ease of heatsinking and the 'no dazzle above the beam' effect, which is definitely sociable in a caving light.

I'm not too impressed with their beamshape graphic, since it makes it look like the downspill is a defined beam, rather than basically being a bit under half of a naked LED's tapering flood.
I think the animated one on my website is better.

biff said:
Musing on, you could patent a tilt mechanism on the LED that points down into the reflector so you can vary the balance of light onto the reflector (for focus) and the amount missing the reflector (for flood) ------------- or at least you could have if this idea wasn't now in the public domain.
They did have a nice idea in one of their headlamps, where the LED is on a pillar, and the reflector can rotate to bring in different sections with different spot beam profiles.

biff said:
That might be the XM-Ls and also XP-G S2s (same sort of colour bins as the R5s), but Im splitting hairs.
I could use XM-Ls for the flood beam, and probably will at some point, but the efficiency difference at low-medium powers is pretty small.
They'd be a bit large for the spot beam, and make it too wide and less intense - for a light designed for performance at low powers, that wouldn't be great.

If had a wish, it'd be for an LED with inner and outer zones on a single die that could be used to give an 'electronic zoom', but unless CREE or some other maker thought they could sell tens or hundreds of millions, that probably won't happen.

I tried using with 1/4 dies on an MC-E, but didn't really like the results. Maybe different optics could make that workable, but to cover the 'join', they'd probably have to give a fairly fuzzy/diffuse beam.
 
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