Triton JR problem

[strideredc]

This is one for the battery guys; I am in the right place…

I had been charging my 10,00 mah d cells on my triton jr for a while now and all seemed ok but I have been getting less and less runtime out of my regulated 7.10v 6 d cell mag.

The other day I connected all the cells together with my 24k plated magnets and charged them as normal… got the beep beep and put them in my light, it lasted 5 min before going out?!!? I checked the voltage and all the cells where the same (can't remember what now). Then I thought I would charge the cells individually, wow! Some cells took 90,000mah and some took 1000mah. What's the deal with this? Can't you charge cells in series? I don't mind charging them one by one but its is a bit of a pain.

The same thing happened when I tried this with my 8aa FM adaptor with enloops, much more runtime than charging all of them together???

 

[VidPro]

just for information gathering sake
what was the rate of charge you were using?
what are the cell brands/type?
what is the rate of discharge?
and your normal method for charging them is in series?
were they locked into a Pack or could you have seperated them for single charging without much trouble?

Charging:
i only know One way to series charge ni-mhy, and that is slow, for two reasons, termination detection on a series pack is very difficult, and if you get termination properly, you still need to have a top off charge to "balance" out the battereis that are not fully charged, when the first 1 or 2 here and there Vdrop (so the computer can see a reason to terminate).
or of course a tapped pack for balanced charging.
IF you have a smart charger you MUST go fast enough for it to determine Vdrop and terminate, unless it has temperature termination , if you sllllooooowwww charge , you must go Slow enough that it doesnt go past overcharge specs.


my series Dcell ni-mhy lights and power tools, use dumb slow charging, and work for years and hundreds of cycles, and are still working, with stupid stuff like $15 wall warts, and i charge right in some lights in series. many of the consumer ni-cd and ni-mhy charge in device (series) chargers do the same thing, low slow and dum, wait forever for it to charge.

Discharging:
then anytime a single cell in the seires pack is fully depleated, the evil reverse charge comes to play, and damages the already low capacity cell, making it even lower capacity than it was before, which subjects it to even more reverse charge again on full depeletion, it keeps getting worse and worse.
so when this configuration starts drooping in output , you must stop the load (shut off the light) because one cell has depeated, and is about to head to reverse charge.

so you got 2 factors here that are possible for your problem, the charge and the discharge. and the worst is probably the discharge , unless you recharge always before full depleation, or have cutoff curcuits.

Matching cells:
ok 3 problems because some cells are not very reliable, are not intially balanced in capacity, get flakey over time, or have more self discharge than the items they are teemed up with, and dont handle reverse charge as well.

i dont have a Triton Jr, some because of cost, some because they are a bit to fast for me (mabey i am gettin old) :tinfoil:
the triton Sr , and the newest triton 2 thing, have improved thier alogrythms, and detect cutoff, taper, and top off, much better than earlier models (according to specs and data and user data).

Prefer single channel single cell charging:
IF you can seperate them and singularly charge them for less problems. single cell charging you can go fast without seires charging issues. or dumb slow charge them in series overnight. I would say parellel charge them too but that can be a problem Too, unless you voltage high terminate like li-ion would, no ni-mhy charger works that way.

Cutoff in device:
if you can stuff a low cutoff curcuit in the light that would terminate anytime the batteries are like this 1.1v 1.1v 1.1v .6v or similar, (some math required) the light would stop before destroying the cells. with extreeme loads the cutoff would have to be figured for the load.

Again, i dont have that charger, just know of the ramifications of both series and parellel charging, and series discharging.

it is possible that you could singulary cycle the cells, and recover a few usable ones out of it, but if you remake the SERIES assembly or team, you would prefer the batteries to be matched, matched in age capacity and acting in similarity.

 

[SilverFox]

Hello Strideredc,

The problem may be that your cells are out of balance, which leads to the possibility of cell reversal, as VidPro has mentioned.

Cells in a battery pack become imbalanced with use. When you first notice reduced performance, it is time to balance the pack. The Triton Jr adds some complexity to this with the way it is set up.

Let's start at the beginning. The first thing you should do is to charge the pack for 16 hours at 0.1C. Now you should have a balanced pack. After 5 - 10 charge/discharge cycles, the imbalance will start to affect performance. At this time, you charge normally, then let the pack continue to trickle charge for a few hours. This should bring things back to a balanced condition. After around 20 cycles, you need to start with a mostly discharged pack, then once again charge for 16 hours at 0.1C.

In your case, the Triton Jr terminates the main charge after 90 minutes, with the cells charged to around 95%. You will get better performance from your pack by leaving it on the charger for awhile after the main charge. The Triton Jr will continue to trickle charge until you disconnect the battery, so this trickle charge can be used to balance the pack.

The problem comes with the initial 16 hour 0.1C charge. You may have to skip this, unless you are up to resetting the charger every 90 minutes.

This brings up another possibility. With the 90 minute timer, you have to choose a charge rate that will fully charge your cells in 90 minutes, or do multiple charges.

I agree with VidPro that if your cells are out of balance and you are charging them in series, you need to use a low charge rate. 0.1C is ideal for this. However, if your cells are balanced, I prefer charging series packs in the 0.5 - 1.0 C range.

Tom