REVIEW: CREE MC-E Diving Light

[gcbryan]

The pressure will be equal to when you put the batteries in on land. Maybe a hair more at depth. Pressure should not be an issue.

mksmith this is a fantastic light. For $81 nothing else even compares. It is better than most 10w HIDS I have dove with especially in high viz places that we get alot here in Florida. IF you have a problem it is still worth the hassle because of the low cost...

In reference to mine, I'll take the driver pics when I get home this evening. I have been direct driving the P7 with 4 18650 in parallel for now. It is alot brighter than the current driven version.
I just addded my own reed switch in the existing light head so I can still use the magnetic switch.
One good way to salvage a broken light instead of going through DX....

So did you add the reed switch to fix the standyby light on issue or was it for some other issue. Please explain.

 

[gcbryan]

I agree completely as well. I couldn't find anything comparable and even the $500++ lights are a horrible use of space and don't use the latest advances in LED's and batteries to maximize output, runtime, or size.

What would the pressure be inside a sealed tube at depth? Maybe the (most likely cheap) OEM batteries are having internal chemistry issues with the pressure? My friends and I are having no issues but we are also using better, well reviewed best in class batteries. There is lots of info on the general shoddy construction of most cheap Li-ion batteries. This would seem to be the weak link as opposed to common off the shelf integrated circuits used in the switching mechanism.

These are the accepted best 18650 protected batteries
AW 18650 Protected 2200 mAh Rechargeable Lithium Battery

These are newer with even longer runtime, but you have to REALLY know how to solder to add a button top to them to use in these lights. Be careful!
AW 18650 Protected 2600 mAh Rechargeable Lithium Battery - New Version

Just another idea...

Dennis.

It's hard to say but there are plenty of people who aren't having problems who are using the batteries that came with the light. Pressure in the light should be that of sea leve. My soldering skills are up to putting button tops on batteries. Why don't they come that way?

My batteries test out fine, of course I can't test them while underwater.

I tested the light in the freezer and then refrigerator as far a tolerance for cold and that was no problem.

I'm pretty sure it has something to do the drivers/magnetic switch.

 

[adm3745]

I just took out the entire driver instead of trying to fix the standby issue. I installed a new reed switch in the Brass pill. So now it is direct driven and only has on/off mode. The benefit is I'm probably getting around 700 Lumens. I'm going to buy a 1 mode 2.8 A output driver soon.

 

[DennisKW]

It's hard to say but there are plenty of people who aren't having problems who are using the batteries that came with the light. Pressure in the light should be that of sea leve. My soldering skills are up to putting button tops on batteries. Why don't they come that way?

My batteries test out fine, of course I can't test them while underwater.

I tested the light in the freezer and then refrigerator as far a tolerance for cold and that was no problem.

I'm pretty sure it has something to do the drivers/magnetic switch.

Hey, good idea on testing in the freezer! I don't doubt that it could still be the switch, but if the pressure doesn't increase much why would IC's fail? Magnetic issues somehow where some lights magnets don't work correctly at depth? Not strong enough magnet? I know seawater gets between the switching ring/magnet and the light body because I have had sand or similar in there crunching around but with no ill effect.

However, you might as get better batteries anyways for a multitude of reasons, plus you can always re-use them in your next light. Widely varying construction/chemistry/capacity is seen across even the same brand of cheep batteries so I still like this reason as a possibility.

The reason the newer 2600mAh AW cells are flat top is still under discussion, but it seems that many lights support this with springs at both ends. Regardless, read this before doing any soldering onto Li-ion cells!

Soldering wires to battery terminals - TechNFun.com

I had ordered a few of them as the latest and greatest without thinking about the flat top issue. Unfortunately, I couldn't use a magnet spacer to fix the positive connection because it interfered with the magnetic switch on the dive light. I also didn't want to re-buy 2200mAh AW's for such a simple problem so against the prevailing wisdom I re-read Fallingwater's primer on soldering Li-ion batteries here and decided to go for it and just add some solder blobs to the positive connector.

And everything went beautifully! In fact, things went so well I did all 6 of my batteries instead of just the "top" ones and even went back and found some old 17500's with not-so-buttony buttons and fixed those too. However, I followed all of Fallingwater's precautions using a high quality soldering iron set to 475C, fixing the battery in a vise, and roughening up the surface with a Dremel cutting disc. I practiced on a used CR123 first and found that slowly building up the solder button with multiple very quick 1-2 second passes is best, with the first pass taking no more than 2 seconds and the subsequent passes being more like 1 second. I built up a nice dome on each and then filed a flat spot on top for hopeful maximum connection.

I tested voltage and ZTS capacity immediately before and after soldering with no change, and then did a discharge and charge test with no issues. Each soldering pass was so fast the top of the battery didn't even get warm to the touch, so I didn't expect any issues anyways.

 

[DennisKW]

I just took out the entire driver instead of trying to fix the standby issue. I installed a new reed switch in the Brass pill. So now it is direct driven and only has on/off mode. The benefit is I'm probably getting around 700 Lumens. I'm going to buy a 1 mode 2.8 A output driver soon.

Oh, here's a trick that may work for some that I found by accident. Put a tiny spacer magnet (used for extending cell buttons) on the top cell. This turned my light to HI regardless of switch position.

Dennis.

 

[gcbryan]

Where do you get those spacer magnets? Can you get them locally or do you have to order online?

It's interesting that you mention this because I just went to Fred Meyer and found a stack of 6 nickel sized magnets. I found that by using them in one direction (polarity) and by moving them just in the area where is say "standby" that I could get the light to go on and off.

I'm planning on a test dive tomorrow night and I will take the magnets with me. If I could quickly find a spacer magnet at Radio Shack I would try that as well.

I may order some better batteries at some point but I don't have time before I need to figure out whether I'm sending this back or not. Soldering the batteries is outside my skill range. (looking a CPF it looks like there are some real downsides to battery spacers as well).

 

[DennisKW]

Where do you get those spacer magnets? Can you get them locally or do you have to order online?

It's interesting that you mention this because I just went to Fred Meyer and found a stack of 6 nickel sized magnets. I found that by using them in one direction (polarity) and by moving them just in the area where is say "standby" that I could get the light to go on and off.

I'm planning on a test dive tomorrow night and I will take the magnets with me. If I could quickly find a spacer magnet at Radio Shack I would try that as well.

I may order some better batteries at some point but I don't have time before I need to figure out whether I'm sending this back or not. Soldering the batteries is outside my skill range. (looking a CPF it looks like there are some real downsides to battery spacers as well).

A spacer magnet is any small 1 or 2mm x 5-9mm or so rare earth magnet that will fit on the battery. It might not work so well with the round button OEM battery but will probably be ok.

Just get the AW 2200mAh batteries that do have a button top. They will probably last almost as long anyways, and more than most any normal rec dive.

I have a couple more lights on order, I figure I will always have a couple that work and I am still way ahead of the price curve given I always need 2 or 3 for the girlfriend and a friend.

Dennis.

 

[gcbryan]

I think I have more or less decided that I am not going to send this back.

Someone else suggested that perhaps it's a cold solder joint on the board or a broken trace and is made worse with the combination of heat and a little flexing with pressure. I don't know how the board is mounted (I haven't taken things apart yet) but perhaps just a little flexing of the housing is being transfered to the board.

As long as the light works above water and does flood underwater I'm sure I'll eventually be able to figure it out. I'd rather be able to be hands on with the light anyway as opposed to having $600 into it and have to send it to the factory because I don't know what I'm doing!

 

[DennisKW]

I think I have more or less decided that I am not going to send this back.

Someone else suggested that perhaps it's a cold solder joint on the board or a broken trace and is made worse with the combination of heat and a little flexing with pressure. I don't know how the board is mounted (I haven't taken things apart yet) but perhaps just a little flexing of the housing is being transfered to the board.

As long as the light works above water and does flood underwater I'm sure I'll eventually be able to figure it out. I'd rather be able to be hands on with the light anyway as opposed to having $600 into it and have to send it to the factory because I don't know what I'm doing!

How about returning it for a replacement? Seems like the dimming problem doesn't happen to everyone? Lots of reports of it working down to depth fine. The DX replacement process takes forever, but they do have one and it should work. Other than that, seal up the bezel with loctite and maybe replace the o-rings and you should be good to go!

I have made another exhaustive search on lights and the only one that uses current tech 18650 batteries and LED's are all European (still service issues) and over $500 except for the Intova Super Nova which isn't bad, but sort of hard to find and varies in price from $250 to $300++. Maybe their production run is sold out?

Regardless, I think we are at a tipping point in dive lighting where there should be a flood of current tech lights coming on the market soon. As just a rec diver I am going to make these DX lights work until I have some real choices to choose from.

Dennis.

 

[gcbryan]

Good news! I went diving tonight. I brought some magnets with me to experiment when the light dimmed. I had been able to turn the light on and off at home with these magnets so I bought them with me underwater.

The only other thing I did differently was to use the Trustfire batteries I ordered as a second set. I'm not sure what brand comes with the light. They are blue like Trustfire but aren't branded.

Anyway...I never had to mess with the magnets as the light never dimmed. I took it all the way to 100 fsw and total dive time (multi-level) was 45 minutes. It seems the problem is solved.

I'll switch back to the other batteries some time just as a test but it seems to have just been the batteries even though they test out as expected.

On an unrelated note...I have a $20 Romisen 3AAA light from DX that I experimented with trying to make it a dive light. This made it to 100 fsw as well. No leaks. It puts out about 100 lumens and is only 5" long and 1" in diameter. The $20 price includes the batteries I had to buy. Other than that I used about $3.00 worth of epoxy and silicone sealant.