Haikelite MT03 over discharging batteries

Wow, those differences between the cells are the most disturbing of all…
Were they not matched, or did you use some more often than others, or is your charger bad?
One of them is still good, apparently (3,5 Volts).

But i guess parasitic drain is at play here.
This is why it’s quite silly the switch lights up when the light is ON, not when OFF to remind you you should lock out by screwing the head half a turn from the battery tube.

Yes, this happened to me almost exactly with my VTC5s in a MT03 recently. After a week or so off and in standby, I go to turn the light on and nothing…. Measured voltages and all 4 were close around 0.65 volts!!

I know this is a scary deep discharge and bad chemistry goes on in cells discharged this low. I could not even attempt to recharge them initially as all of my chargers assumed the cells were NiMH. They have now, as I just checked after banishing them a week ago, recovered to around 2.2 volts. I just tried one and my Li-500 is now accepting the cell as a nominal 4.2v cell. Even if they do accept a charge, I expect the capacity to be shot. I don’t think I can trust the cells and I certainly don’t trust the MT03 any more unless I empty it of cells when not in use. Not sure I have the patience for that sort of nonsense!

Yes, anyone with this light should be very careful!

That reminds me, you may have seen my topic about modding the MT03, and the first thing i did was the mandatory bypassing of the springs with 18AWG silicone wire.
But it had some bits of glue on the + battery contacts which could cause some contact problems, although i didn’t notice anything wrong with the batteries.
It’s probably the glue they used for the reverse polarity protection rings.
You might want to check that out.

Yea my one is modded so the batteries fit proper. The standby current must be really bad! Honestly i have not used it since my review i have no need for so much light but i wanted a laugh so i thought id start it up that was an expensive laugh lol

I am honestly surprised the batteries have not been in here very long at all.

I always cycle my batteries but i dont worry about them for a few months at a time.

That’s a bummer Chris. I wonder if the newer variant MT03II has the same drain value…

Okay, both Chris and Keepitsharp have the old version?

Yea 2S2P I have the very first model before production. I will go through the driver and see if i can find the cause.

Chris has the review sample, which I’m pretty sure is 2S2P very first generation… Is that right Chris?

Even being 2S2P at least both sets should be draining fairly even.

Woah, the standby current scares me
How much is that

That problem there can only be caused in the battery tube or you may have used mismatched cells.
I use a set of four new VTC5 in mine (well, when it was still working :smiley: :smiley: ) which i will only use together in the MT03.
I just had a look and they’re all 3.61 Volts

I agree. Has the standby current been measured?

33 µA on my 2S2P early batch one.

edit: I take that back, now I get 665 µA… I’ll have to do some more checking.

So, this is disconcerting, with only two cells, I get the 665 µA but with all four I get 62 mA.

Sorry, was away for a bit. My MT03 is one that Haikelite sent me new 2S2P plates and driver to replace my 4S about a month ago. I resoldered these in and I am not at all sure whether it is now V1 or V2 and I am not taking it apart again! Nor do I want to put cells back it it as I don’t trust mine anymore.

This is not very much. It’s hard to believe it would account for the complete discharge of the cells in less than a year.

Edit: OK he remeasured and got 665 microamps. This current would deplete 1000mAh in 60 days.

So here’s the photos from my measurement from one pair of batteries and with the other one connected too.

I find this strange, since I got the 33 µA back when I did the review.

That’s crazy…
How can the parasitic drain be so much more with 2P ??

Maybe an EE/driver expert could chime in. And no, the light wasn’t lit during either of the measurements :slight_smile:

I’ll leave the cells in for couple of days to see if they’re drained.

I’m really baffled now. Since all of my meters gave conflicting numbers, I tried a clamp. It reported ~22 mA with all the batteries connected. So a week should be enough to drain 3500 mAh batteries.

I will try and charge these cells if they rest at higher voltage and measure standby drain.