Ebay win... what have I bought???

[BenChiew]

I sold a like new condition only 5 weeks old turnkey Malkoff MD2 on Ebay I started the bidding at only 99cents and a guy won the bid for only $32.00 so it was very good for the buyer but not so good for me.

Why didn't you list it here on CPFMP where Malkoff is known?

 

[Craig K]

Why didn't you list it here on CPFMP where Malkoff is known?

I put it on Ebay because I have used Ebay a lot before but I have never used CPFMP and I don't know how to sell stuff here but I wish I did because I only got $32.00 for a mint condition turnkey Malkoff MD2

 

[BenChiew]

Get yourself registered in CPFMP. Go to the correct section and start a new thread with your offering.

 

[gravelmonkey]

Hi

I have two Trustfire 2400Mah batteries and as it happens (purely by luck!) two of the batteries that I bought are exactly the same!

The ones I have have only had one charge, I read somewhere that the Trustfire are an OK Budget battery (or did I imagine it??)..

This is the charger that I 'won' on Ebay, Is it not up to much??, it's supposedly an intelligent charger that will charge most types of cells??


Many thanks for all the help- wouldn't want to come to a sticky end!!



Kind regards, John..

Trustfire can be a bit hit or miss, at least you don't have any outrageous claims (currently, anything above 3400mAh in 18650 format is lying).

1) When you get the cells, write on them with a marker pen (A,B,C,D or 1,2,3,4), note down which ones were the original pair.

2) Measure the voltage of the new cells (as usual before charging: should be preferably >3V when resting, if it's 0V then either the protection has tripped or you have a dead cell). If the voltage is ok, go ahead and charge up all 4 cells (on something fireproof, I normally do mine on the granite worktops in the kitchen as it's easy to moniter)

3) Note their charge straight off the charger, then measure them an hour later, then ~12-24 hours after that. They should all be ~4.2V hot off the charger, after that, a slight fall in voltage is natural, anything abnormal (like a fall to <4V) indicates a faulty cell and should be re-cycled.

4) All 4 cells should behave in the same way, if they don't then I wouldn't recommend using them together.

Note: This is only a very basic test and doesn't necessarily mean the cells are safe, it just helps to weed out any dangerous cells. If you have a bad cell and it decides to kick off while charging, then you have a horrid, toxic fire. If you're running cells in series (as you are in that light), and the protection fails, one duff cell can be 'reverse charged' which can cause it to kick off and you have what happened in the link |Night| posted.

I'm sure Benchiew or HotWire will highlight anything they'd do differently to above.

 

[Johnbaz]

Trustfire can be a bit hit or miss, at least you don't have any outrageous claims (currently, anything above 3400mAh in 18650 format is lying).

1) When you get the cells, write on them with a marker pen (A,B,C,D or 1,2,3,4), note down which ones were the original pair.

2) Measure the voltage of the new cells (as usual before charging: should be preferably >3V when resting, if it's 0V then either the protection has tripped or you have a dead cell). If the voltage is ok, go ahead and charge up all 4 cells (on something fireproof, I normally do mine on the granite worktops in the kitchen as it's easy to moniter)

3) Note their charge straight off the charger, then measure them an hour later, then ~12-24 hours after that. They should all be ~4.2V hot off the charger, after that, a slight fall in voltage is natural, anything abnormal (like a fall to <4V) indicates a faulty cell and should be re-cycled.

4) All 4 cells should behave in the same way, if they don't then I wouldn't recommend using them together.

Note: This is only a very basic test and doesn't necessarily mean the cells are safe, it just helps to weed out any dangerous cells. If you have a bad cell and it decides to kick off while charging, then you have a horrid, toxic fire. If you're running cells in series (as you are in that light), and the protection fails, one duff cell can be 'reverse charged' which can cause it to kick off and you have what happened in the link |Night| posted.

I'm sure Benchiew or HotWire will highlight anything they'd do differently to above.

Hi GM

Your info sounds like excellent advice regarding the testing and safety procedure but all this has gotten me a little scared, I think i'll just use it with two cells and not bother with the extension :shakehead


Cheers, John

 

[BenChiew]

You still need to exercise the same care and caution as detailed by gravelmonkey. The dangers of running 2x18650 as compared to 3 pieces is still the same. You just need one of them to be faulty and you have a pipe bomb.
As I mentioned earlier, your risk only decreases if you run them in singles or individually. Having said that, it does not mean that you can be lax on your charging.

I presently use a dual bay XStar VP1 charger that has a voltage and status display. When you first put a spent rechargeable in the bay, it gives you a reading of the voltage before commencing the charging. If you have a paired battery, you can detect if there is a big voltage variance between the 2 batteries. After charging, it will give you a reading of your resting voltage. Again you can see if the variance between the 2 is small or large. Have a decent DMM with you incase you need to recheck it.

 

[Johnbaz]

You still need to exercise the same care and caution as detailed by gravelmonkey. The dangers of running 2x18650 as compared to 3 pieces is still the same. You just need one of them to be faulty and you have a pipe bomb.
As I mentioned earlier, your risk only decreases if you run them in singles or individually. Having said that, it does not mean that you can be lax on your charging.

I presently use a dual bay XStar VP1 charger that has a voltage and status display. When you first put a spent rechargeable in the bay, it gives you a reading of the voltage before commencing the charging. If you have a paired battery, you can detect if there is a big voltage variance between the 2 batteries. After charging, it will give you a reading of your resting voltage. Again you can see if the variance between the 2 is small or large. Have a decent DMM with you incase you need to recheck it.

Thanks for the advice Benchiew, I did think that with just two batteries the problem would be much lessened but you're right, if it only takes one to go down then there is still a danger then :thumbsup:

When I tested the voltage of the two batteries that came yesterday (the ones that should have come with the torch) they were both reading 3.7 volts, again, there were no instructions so I didn't know if I should have charged them or not , I gave them one hour charge and they came up to 3.9, I left it at that not wanting to blow the kitchen up!!

I'll test them again if I can remember where i've put them! I put the Trustfire are back inside as I thought i'd read that were weren't too bad..


Cheers (for keeping me unharmed!!) John

 

[BenChiew]

Starting with 3.7v and charging for an hour should easily put you in the realm of 4v and above. The cut off is 4.2v hot off the charger. Once it has rested, it should be around 4.17 or 4.18.

You need to check your charging current is set to 1amps and not 0.5amps. Since 18650 is a large battery, it will take a 1amp current. The 0.5 is meant for smaller batteries that does not exceed 750 mA.

 

[RedForest UK]

While 4.2v is the rule, good chargers use a CC/CV algorithm for charging. This effectively means that near the end of the charge they lower current until the cell is 'full', which they tell by when it is no longer accepting above a certain amperage from a set input voltage. This means that older cells will not necessarily come off the charger at 4.2v, but maybe between 4.12 and 4.17. They will then drop a little more once rested. If they don't hold a voltage above 4 or 4.05v they probably need retiring.

Trustfire 2400mah 'flames' are some of the best budget branded cells, as long as they are genuine. I would expect you'll be fine as long as you stick with matched pairs. It might be worth mentioning what other exact types you got though, as some particular ones are known for being very poor quality and inconsistent capacity (such as BRC or Ultrafire 3000mah).

 

[mesa232323]

From experience, the batteries aren't the greatest...

The large one below is a Trustfire tr-1200 not an Ultrafire. It is my go to light and the one I lend to family members or children to play with and abuse in the yard. I would say it's thee most "practical" light I own for any purpose except EDC. FM even makes an adapter for the drop in LED module for a Maglite. I highly recommend this light for price/reliability/runtime/brightness.

The Ultrafire below is a 18650 host for p60/d26 drop-ins. I EDC that light and own multiple. I prefer this host over my Solarforce or Surefire hosts because I don't feel bad dropping it. It's reliable, smaller, can be left in your pocket while going through the wash ;-) and always makes a great electrical connection to my drop-ins.

These brands have a bad rap by most people who don't even own a xxxx-fire light. What I'm trying to say is not to judge it until you try it. If anything else, you'll have an aluminum hammer that illuminates.