PXC / Ozito 2x4Ah battery + fast charger $109

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Forums › Bargains and Deals › PXC / Ozito 2x4Ah battery + fast charger $109

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SirHumphreyAppleby

2506 posts

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#2961720 31-Aug-2022 21:23

Jaxson: Any recommendations on a nice drill to pair with these.
After just a solid standard drill.

The basic Ozito drill they sell in the cheap kit is a bit rubbish. Gets the job done, but it feels like it should spin much faster. Okay for wood/aluminium, not so much if you want to drill into brick or steel.

I'd probably go for the brushless hammer drill if I had more of a use for the drill. I mostly use the driver (I have two of the cheap ones), and they're fine.

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pih

558 posts

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#2962853 3-Sep-2022 19:46

Regarding the coil whine, I returned my unit to Bunnings today and it turned out the Ozito rep was in store. Asked him if he'd heard it before and he said no. We plugged it in and sure enough there it was. In the store you had to put your ear close to it to hear it, so we unboxed another one and... Same noise 😳. The second one was a little quieter, so I ended up swapping them anyway, but that was disappointing.

neb

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#2962861 3-Sep-2022 20:11

pih: Regarding the coil whine, I returned my unit to Bunnings today and it turned out the Ozito rep was in store. Asked him if he'd heard it before and he said no. We plugged it in and sure enough there it was. In the store you had to put your ear close to it to hear it, so we unboxed another one and... Same noise 😳. The second one was a little quieter, so I ended up swapping them anyway, but that was disappointing.

It means they've saved a few cents by not sealing a ferrite somewhere. If it's an open toroidal inductor (quite likely) you can try encasing it in hot glue to try and damp the whine down, in less budget-critical consumer electronics they're usually potted to deal with this.

Can you post a photo of the insides for the peanut gallery to comment on?

Jaxson

7678 posts

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#2963195 4-Sep-2022 22:01

SirHumphreyAppleby:
Jaxson: Any recommendations on a nice drill to pair with these.
After just a solid standard drill.

The basic Ozito drill they sell in the cheap kit is a bit rubbish. Gets the job done, but it feels like it should spin much faster. Okay for wood/aluminium, not so much if you want to drill into brick or steel.

I'd probably go for the brushless hammer drill if I had more of a use for the drill. I mostly use the driver (I have two of the cheap ones), and they're fine.

Went in for the Ozito and came out with the Ryobi ONE+ deal in the end.
Brushless Drill and Driver and two larger alacrity batteries for $249.
Not a dual charger but looks pretty nice and has a decent manufacturer warranty.

pih

558 posts

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#2968332 14-Sep-2022 22:40

neb:
It means they've saved a few cents by not sealing a ferrite somewhere. If it's an open toroidal inductor (quite likely) you can try encasing it in hot glue to try and damp the whine down, in less budget-critical consumer electronics they're usually potted to deal with this.

Can you post a photo of the insides for the peanut gallery to comment on?

Sorry for the delay, finally got the thing pulled apart tonight to investigate. It's interesting:

There's a step UP transformer on the mains input on the right side which bumps the input up to ~337VDC. Weird. Then feeding off that is two switched mode step down supplies, one for each battery.

It's the two yellow and black transformers making all the racket. As suggested (thanks) I entombed them in hot glue, and now the squeal is barely perceptible! I just hope those transformers don't get too hot...

neb

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#2968334 14-Sep-2022 23:33

pih: There's a step UP transformer on the mains input on the right side which bumps the input up to ~337VDC. Weird. Then feeding off that is two switched mode step down supplies, one for each battery.

It's the two yellow and black transformers making all the racket. As suggested (thanks) I entombed them in hot glue, and now the squeal is barely perceptible! I just hope those transformers don't get too hot...

PFC circuitry perhaps? Looks like an LC hash filter at the input, but then it looks like the bridge rectifier is after the transformer not before it which is where you'd expect it for PFC circuitry... and I can't see any switchmode controller IC by the chopper transistors, are the second set of heatsinked TO220-ish devices linear regulators and they're relying on those for regulation? Definitely a weird design, must tear my (standard) charger open again and see what's in there, I remember missing any obvious SMPS controller in that as well.

In terms of hot glue, you could always run it for awhile, yank the case open, and point an IR thermometer at it to see what maximum temp it reaches. Worst case the glue will go soft and then re-harden as it cools. Assuming it won't get hot enough that it's risking transformer failure but just affecting the hot glue you could try epoxy putty, e.g. Knead-It.

neb

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#2968858 15-Sep-2022 23:38

I've pulled my standard charger apart and the circuitry is identical, there's just a single SMPS instead of the dual ones. The chopper is a CS7N65F power MOSFET and the second TO220 is an HBR10200 Shottky barrier rectifier. There's definitely a feedback circuit to the chopper via the EL817 optocouplers, but everything else on there is passives, a few capacitors and a resistor. Unless they've hiding a TL494 or something on the underside there's no PWM controller running the chopper.

Ah, and mine doesn't have the LC filter on the input, but it's also a 2017 design. Maybe they got complaints...

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