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Not related to Pews - polarity question.

Dan Robinson

By Dan Robinson,
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Dan Robinson Veteran

Dan Robinson

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Am,I right in thinking if you get the polarity wrong on a charger you can blow the circuit board of the device you're trying to charge?

 

Reason being, I have an old FLiR i7 thermal camera that the boy and I were going to use on a game day, so we did a battery test.  Happy to discover that despite it'd age, there was a good 5 hours battery life.

 

I then had to lend it to a customer (long story) who tried to charge it using an adapter he had at home that was the same voltage but it turns out unknown polarity).

 

When I got it back there was about 5 minutes battery life left, and when I plugged it in with my charger it wouldn't take any juice.

 

So I know the battery was/is good, so he's either fried something on the camera or my charger has spontaneously shat itself  (my multimeter is too chunky to get inside the plug to measure the angry pixies).  Possibly a blown diode?

 

Tah in advance!

 

 

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Rogerborg Grand Master

Rogerborg

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If a lithium battery or cell has dropped below the voltage where a smart charger will touch it, I've recovered some using a few seconds of parallel connection to a dumb source of the appropriate voltage (i.e. about 4.2V per cell).  I don't mean leave it like this, just do it for long enough to nudge its voltage up, even very temporarily, to where the charger will kick in.

 

If it's gubbed anyway you've got nothing to lose* by trying it.  I've recovered 18650s that had dropped below 1V this way.  You won't get the full capacity back, but any re-use is better than re-cycling.

 

* If done in an Explosion Containment Pie Dish.

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Dan Robinson Veteran

Dan Robinson

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25 minutes ago, Sewdhull said:

If there's reverse polarity it would likely be a series diode, it's a small load and it shouldn't fail even if the polarity was reversed.

Does it show it's charging?

 

The battery comes out on those doesn't it?

 

When its plug in the charging LEDs stay off.  Officially the batteries are not user serviceable, however, I found a place still selling the camera with a spare battery as an accessory.  I suspect it's easy enough to change the battery if you can open the case without damaging it.  I have ordered a new charging brick for it as well as some needle probes for the multimeter if only to eliminate that side of things.

 

2 minutes ago, Rogerborg said:

If a lithium battery or cell has dropped below the voltage

 

Pretty sure the voltage is still OK as the camera knows to shut itself down before they get too low.  This it has done perfectly well for years (I bought it new in 2009).

 

6 minutes ago, Rogerborg said:

 If done in an Explosion Containment Pie Dish.

 

Big Clive would be proud - I've done this in a Yoku Moku box a few times.   Have also tried to restore a DJI battery that was well below voltage, but the PCB is sneaky and knows that the cells were discharged, even if you managed to bring them back - I even disconnected them from the main PCB.

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EDcase Grand Master

EDcase

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EDIT: This was typed before you replied so info is a bit out of sync

 

Most circuits have polarity protection so the board should be fine.

 

As Roger said, if the battery charge drops below a certain point an intelligent charger won't recognise it.

I have recovered a couple of very low bats by setting the charger (B6AC) to NiMh mode and charging for 2 mins.  This pumps in enough charge for the intelligent charger to recognise it. 

 

Probably a good idea to change the battery anyway.  Even if it shows a charge it probably won't last long under load when actually being used.

 

 

Edited by EDcase
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Dan Robinson Veteran

Dan Robinson

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Not on this model:

 

Compress_20240121_143224_4703.thumb.jpg.3dfd58b9196182f8e7ce38d52f906049.jpg

 

Compress_20240121_143224_4500.thumb.jpg.414f02be7f49e6ab2a5481e86db9babf.jpg

 

Compress_20240121_143224_4854.thumb.jpg.eacacb8ce9f88f0c0a7c1b407a8bcbee.jpg

 

Hunting for my spudgers right now.

30 minutes ago, Sewdhull said:

The charging area unclips from the top does it not

 

 

Ah - not the top - but the back of the handle....  Now don't I feel like a plum LOL.

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Dan Robinson Veteran

Dan Robinson

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Whelp - got inside and to one side of the PCB.  Was half hoping the charging circuits would be on a secondary board, but hey ho.

 

Nothing seems to have gone pop on this side, but the socket is soldered to the other side, and I haven't got the kahunas to take it apart further incase I damage the screen or lense.

 

Found a comment on Youtube that also mentioned a blown diode. At least I have the battery out now so I can check that tomorrow when my new probes arrive.

 

Compress_20240121_151643_3840.thumb.jpg.e0caaed25ac8757d504cecdfb92eca0a.jpg

 

 

The battery is just an 1860 with a thermistor stuck to the side - so that is easy enough to deal with.

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gavinkempsell Grand Master

gavinkempsell

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I know SFA about this but there are apps you can use on your mobile that will do the same job, The plumber that serviced my heating used one to show me the 'thermals' of each radiator.

(just in case you can't get it sorted)

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Dan Robinson Veteran

Dan Robinson

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58 minutes ago, gavinkempsell said:

I know SFA about this but there are apps you can use on your mobile that will do the same job, The plumber that serviced my heating used one to show me the 'thermals' of each radiator.

(just in case you can't get it sorted)

 

 

I have one of those too.  I use it to show people how their heat pumps are working and how (usually badly) their underfloor heating has been installed and set up.

 

https://youtu.be/eEbCcYVQeAI?si=B0cBUChrg1PeLGHM

 

My FLiR gun is useful for the minions to use on occasion,  plus possibly when pewing.  It's annoying that something so daft has potentially killed it. 

 

 

3 hours ago, Sewdhull said:

Here,

 

https://www.eevblog.com/forum/thermal-imaging/flir-i5-mk1-teardown-(same-as-i3-i5-i7)-by-fraser/

 

I got as far as reply number 4.

 

?action=dlattach;attach=300488;image;PHP

 

It's shame this photo isn't 180 degrees rotated... one of those little components must be the chappy.

 

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Dan Robinson Veteran

Dan Robinson

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1 hour ago, Sewdhull said:

Have you tried powering from usb?

 

There are other photos from above

 

Yeah, it doesn't do anything,  and I'm pretty sure is never did.  It must either be a way to pull images off the sd card or for firmware updates.

 

Reading that blog, it may mean that the IC is fubarred 😡.  Feck knows what Teledyne will charge to fix that...Well they'll just replace the board if anything at all.

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