PROBLEM:
So my Sola 1200's finally would not hold a charge. I would not go through the gamit of strobing red to orange to yellow to green. It mostly just flashed green for a minute or two and then went solid green...even after I fully discharged it.
I have nursed them for a few years now.
SUMMARY
I disasssembled the battery pack and replaced the cells with Samsung 18650 30Q 15A.
(Original batteries were Panasonic NCR18650BE 3200mAh 3.7V Unprotected 3.63A Lithium Ion (Li-ion) Flat Top Battery). Yes, I used a better battery for about the same price as the originals. The higher current rating does not enhance the light performance (not brighter, not longer lasting, etc.) but it does enhance reliabillity.
I was able to find them with spot-welded tabs.
Note that flat-tops are preferred as the button tops increase the height of the battery which may cause difficulty when reassembling. (I cannot emphasize too much on how little space is available.)
NOTES:
I advise you to use high quality batteries like Panasonic, Samsung, Sanyo, LG and get High Drain with at least 3.63A.
When I use the term " Note.." somethines it may help to take a picture of the item before you disassemble it. Some people find better luck by videoing the entire process. It allows them to "rewind" and see everything before they change it.
Where I describe multiple steps, like 4a) and 4b), I am offering alternates. Do NOT do both 4a) and 4b).
Just do EITHER 4a) or 4b).
Basically the steps were
1) Disassemble,
2) Reassemble,
3) Reset Battery Capacity.
DISASSEMBLE:
1) Take a knife and carefully cut off the battery pack shrink wrap and save the two foam spacers.
2) Take a knife and carefully pry off the bottom cardboard "insulators"
3) Take a knife and carefully pry off the top 1/2 of the cardboard "insulators" above the circuit board
4) Unsolder the black wire at the bottom of the battery, but leave it attached to the small PCB at the top of the battery pack (it's used for overcharging/overdischarging protection)
5) Note the orientation of each PSB edge (solder locaton) to the + and - poles of each battery.
That is, make sure you know which side of the PCB to attach the + side of the battey and which to
attacch the - side.
6) Unsolder the 2 sides of the PCB. A small piece of a battery tab is folded over and soldered to the PCB. You may have to "unfold/unbend" it while applying heat to get the battery to seperate from the PCB.
REASSEMBLE:
(NOTE: Use plenty of flux to minimize the time you heat the battery with the soldering iron when
soldering.
Clean off the excess flux with alcohol.)
1a) Solder 2 batteries together using thier tabs: + on one to - on the other. This will be the "bottom"
1b) If you can't find batteries with tabs, remove/pry the tabs off the old batteries (They are spot-welded, not soldered so desoldering won't work well) from the old batteries (or get replacements- preferred) and solder them on.
This is not the preferred method, as soldering will increase the resistance a bit, but it will work.
While you "could" just solder a wire between the batteries, I would caution against it as the battery pack is so confined inside the flashlight that it might "raise" the height of the battery so that the light can't be reassembled. Somthing thin and flat is needed, like a tab.
2) Solder the black wire from the PCB to the "bottom" connection where you soldered the 2 batteries together. You should have noted this location in step REASSEMBLE(1) above.
Note: You may need to replace the black wire if it is not long enough. It fits on the side of the battery
so you don't have to worry about it causing reassembly space issues.
3) Put some electrical tape over the top (unsoldered side) to prevent the PCB from contacting the batteries (I did this) or cement the old cardboard "insulator" on.
4) Place the PCB on top of the tape.
5a) Bend the tabs over the PCB edges, trim them (as they will be too long) and solder them to the PCB, ensuring no excess solder spreads out to any of the PCB components or traces and ensuring the + and - relationship noted in " Dissassemble (5)" is maintained.
5b) If you do not have tabs, you can use wires, but please roughup the top of the battery with sandpaper/file (to enhance adhesion of the solder), use flux, and minimize amout of time you apply heat to the battery. Again, be mindful of the wires so they don't increase the battery pack height and impede/prohibit re-assembly of the light.
6) Place one of the cardboard "insulators" on the bottom and "tack" it there with some electrical tape
7) Place the other cardboard "insulator" on top of the PCB and tape it in place.
8a) Take some battery pack shrink wrap and shrink wrap the battery pack, similar to what it looked like before disassembly and add the saved foamspacers (if needed). This was VERY easy and creates the most compact battery pack.
8b) Wrap the batteries in electrcal tape. Be careful to NOT use too many layers as there is not a lot of room in the flashlight body, even though the tape looks "thin".
9) Attach the pack to the Main PCB, and reassmble the light. It is helpful to LIGHTLY lube the O-ring with silicon grease. (If I knew what size it was, I would have replaced it. If anyone has a source, please post it.).
RESET BATTERY CAPACITY:
1) Turn the light on to full power and place it in a bucket or jar of water.
Note: Quality new cells typically come with some "charge" from the supplier. If yours doesn't
then adjust accordingly.
Note: Please be reminded that these lights are meant to be used in water, which means water may be a
required "cooling" method. I am not sure, but didn't take a chance.
2) After the light has turned off, turn it on again. It will shortly turn off. Repeat this several times.
Note: This step is to try and discharge the batteries as COMPLETELY as possible.
3) Charge the battery pack
You MAY have to repeat 1,2,3 again, but I did not. I was able to get about 1hr20mins of FULL POWER light after doing this (again, discharging in a large bucket).
CONCLUSION:
It was fairly easy to "rebuild" the battery pack. Cost was less than $20 for two quality cells and some optional battery pack shrink wrap.
When I now plug the light in to recharge it, it goes through the gamit of strobing red to orange to yellow to green like it did originally.
Testing gives me between 1hr5mins and 1hr20mins on fill power WIDE angle. This is about what I had when it was new.