Dewalt DW9118 Battery Charger Teardown

[@zunedog31]

I know virtually nothing you talk about, but that's what makes it so enjoyable. Mind blown every time.

[@britttullos8119]

Great Video! You just gained another follower. This is the type of electronic complement education content I’ve been looking for, for the past 6 months during my personal journey of learning as much as I can about electronics of all kinds.

[@kuhrd]

Typically the silastic on the board is to help absorb mechanical vibration so you don't hear the parts resonating during operation of the switch mode supply. Usually, it is just squirted on the board and during QC they measure the sound output during circuit operation. If it is quiet enough it will pass that step in QC even if it was not applied effectively around the whole part.

[@jusb1066]

it would be cool if an image like this could be printed very large, say 5 feet across, for a wall picture, if it could be done pin sharp....modern art for sure.

[@jusb1066]

***** i did look at the website ones, they would not have the sharpness to be printed poster size

[@superdau]

I'm actively searching for a microscope to do exactly that myself. But until now all the microscopes I found that have an XY-table are at least a few hundred Euros. And then I would have to modify or by a mount for a camera on top of that. Modern art is becoming expensive quickly ;) .

[@stinkycheese804]

The white cement collecting the wood dust did not significantly change the state of the resistor. It runs hot and would have brown-charred the PCB even if were perfectly clean, as mine was, being made prior to their addition of the white cement in that area. Iff anything the cement would have 'sunk away a modest amount of heat, slowing the decay of the solder joints and copper under them, so they don't pull off as quickly. Granted it's no substitute for a larger resistor that runs cooler, and yet despite running hot mine does still work fine with the one exception that I was a bit concerned about the power surge every time I plugged it in, so I moved the AC filter capacitor a little to make room for an NTC thermistor, I added in series to mitigate that.

[@donj.giovanni7551]

I am impressed with your teardown. I have an exact DW9107, WHICH looks very similar to DW9118. For the fun of learning electronics, could I seek your expertise to trouble shoot?

[@stinkycheese804]

Be aware that there was a recall on that model # DW9107 for failure to shut off and burst the battery.

[@donj.giovanni7551]

@@stinkycheese804 Thanks for the recall info!

[@icesoft1]

The sand in the fuse is there to quench the arc when the fuse blows... If you happen to dump out a largish high current fuse that's blown, you'll see the sand 'melted' into the edges of the fuse link where the arc formed as the link melted open. The sand 'back-fills' the gap in the fuse link and extinguishes the arc....

[@terrencesauve]

Interesting video about the IC. I have opened mine, a DW9116. Its also a similar variant of the Delta charger but the B&D IC is trademarked from 2012 "BD2012XR4". Quick question, what would D15 and D17 be? Glass zenners? Trying to troubleshoot that DW9116 and I think I have these similar diodes that are not good. Electrolytic cap, fuse, X1 cap, and fusable resistors are all in good shape. Scotchy diodes on the bridge all good too. I have 3V AC across the output of the charger while charging a dead battery... Perhaps its not AC decoupled. I have two inductors (at first i thought they were a transformer to step down to 20 V) on mine and one had the winding open and the other one they have put a nice heat shrink around it.

[@louisrichards3702]

i have a DW9118 charger and a DW 9116 charger,, the 16 says it has a tune up mode that does a better job of charging,,my 18 does not say that..does the 18 have the tuneup mode?? the charger housings are different..both work good..

[@jakp8777]

I tore down another Dewalt power supply that failed and it was made by PhiHong, another power supply maker. It seems like Dewalt using power supply makers to make their chargers and them failing is common.

[@DaveRepairs]

that was surprising to see a processor on board a charger!

[@handymanbrian8269]

good video. is there a way to convert the charger (20 volt) into a 12 volt DC input (car)? i was assuming that just a new voltage regulator would do.. not sure.

[@AlexandreJasmin]

I'd be careful about that. I recently looked at one of these and noticed the charger output is not isolated from main. What gives this away is that it uses an inductor in place of a transformer. That's fine as long as it's used as intended. The battery contacts are recessed so you can never touch them. Though, I wouldn't risk plugging the output to anything exposed.

[@terjeoseberg990]

I have two identical batteries and this exact charger. It charges one battery to over 13.54v and the other to around 10.5v. The charger says 7.2v to 14.4v on it. It’s it automatically detecting the number of cells in the battery pack or something? I believe that both battery packs, because they’re identical, should be charging to the same voltage.

[@stinkycheese804]

I presume that these are 12V packs? If so, the one hitting 13.54V is about right after sitting off the charger a few minutes but the one only at 10.5V has two shorted cells in it. If these are instead 14.4V packs, then the one at 13.54V has two shorted cells and the one at 10.5V has 4 shorted cells. It can't really detect # of cells because there is no smarts/IC in the battery pack. All it can do is infer the pack voltage based on what it senses so if a pack has shorted cells, it can't determine this. If it had an odd # of shorted cells or more than that, it might rapidly flash the LED. You are facing what most of us did several years ago, that the pack is worn out. I rebuilt mine but they wore out again, not to shorted cells yet but very low capacity. I was mulling my options and opted to rebuild the pack with Li-Ion 18650 cells this time. Mine are 14.4V packs though, it may be harder to fit the 18650 cells into the smaller casing of a 12V pack, unless you start cutting off some of the studs that are used to screw it together. You can get 3S 40A BMS boards cheap on aliexpress then you just need to substitute your own 12.6V power supply (no higher), assuming you have 12V packs and use 3 series cells or 3S2P.

[@jo31b]

Do you know of any videos covering how to trigger different voltages for the multi bolt dewalt chargers?

[@stinkycheese804]

No video needed, you just plug in the appropriate battery. That is all it is designed for, charging batteries with that # of cells and it will equally do that for any other pack with same # of NiCd cells, since there is no intelligent communication between the pack (which is just the series of cells wired to the connector) and the charger.

[@mikerollo8653]

Mine keeps flashing problem powerline can you please tell me what does it mean thanks

[@stinkycheese804]

Probably means that a power surge killed something on yours, or the main filter cap has failed.

[@backyardgrillmaster2910]

Thank you for saving my time :-0)

[@kymo183]

What screw driver did u use to open it sir?

[@stinkycheese804]

Some Dewalt chargers use a torx, T15. If you have a full size range set of security torx you should be set, however their older chargers had plain torx, not security screws. Oddly even on some chargers without security torx, some of the tools that came in the sets with those chargers, did have security torx, and some had a unique combo screw head that was torx15 but also had a slot across it so you could open it with a plain old flat blade screwdriver if you needed to.

[@dieterfischer535]

my dewalt charger output voltage (dc) is 52-53 Volt...what is wrong?,please say me,thanks for video

[@sjon888]

Same check mine way over voltage. Any ideas what is wrong?

[@aircomputersfranca]

51v here. Any idea?

[@stinkycheese804]

If you are measuring it with no load, meaning the battery is not plugged in, that is not necessarily a sign of anything wrong, just the way these float to a high voltage and current regulate to charge multiple different battery cell #s. What does it do when you plug in a known good battery?

[@dieterfischer535]

@@stinkycheese804 than you for reply,ı threw it away many years ago. :) have a nice day

[@kyoudaiken]

What a pity that this turned out to be just a teardown video. :( I don't find semiconductor dies interesting. They all look pretty much the same and on the microscope you still can't figure out how they really work...

[@frederickjones6931]

what tool did you use to remove the top case please ?

[@electronupdate]

+frederick jones case used security screws: had to hand grind a screwdriver tip that would fit

[@JT_70]

T15 Torx security driver. Cheap at Harbor Freight.