1500mah battery charges in 3-5 hours, why does my Kill-a-Watt say the wall wart is drawing 2-3 watts?

[Muse]

Just received a Bauer 4volt 1/4" cordless screwdriver from Harbor Freight. Included is a proprietary wall wart charger. The battery's rated at 1500mah, li-on.

It was functional, but I decided to check out the charging system. There's an LED, which I presume is green...

[RANT] If you design these things, for God's sake don't put a green LED charging light in them that turns red when charged or vice versa. Around 10% of males are color blind and probably most are red/green color blind. I'm total green blind. I have a devil of a time determining of those green/or/red LEDs are red or green. DON'T DO IT! I just also bought a couple Skil cordless screwdrivers and the designers were sensible enough to have an LED that flashes in one state, solid in the other... problem solved. [/RANT]

So, unlike those Skil 4v 1/4" screwdrivers which also have 1500mah batteries, the instructions with the Bauer don't say to charge before using. They do say to not charge the batteries for longer than 5 hours or they can be damaged! I'm WTF, this is li-ion, isn't there supposed to be overcharge protection circuitry built in??? Says to charge 3-5 hours. I'm looking at this thing and can't tell if it's turned red yet. Probably will never know for sure. My Canon ELPH 100S camera has the same problem. The charger has green/or/red LED that drives me nuts.

Now, I have the charger for this Bauer cordless screwdriver plugged into my Kill-a-Watt and it's showing 118v, and when I switch it was show Watts, it goes between 2 and 3. How can this thing charge a 1500mah battery pack in 3-5 hours only drawing 2-3 watts?

 

[sdifox]

Just received a Bauer 4volt 1/4" cordless screwdriver from Harbor Freight. Included is a proprietary wall wart charger. The battery's rated at 1500mah, li-on.

It was functional, but I decided to check out the charging system. There's an LED, which I presume is green...

[RANT] If you design these things, for God's sake don't put a green LED charging light in them that turns red when charged or vice versa. Around 10% of males are color blind and probably most are red/green color blind. I'm total green blind. I have a devil of a time determining of those green/or/red LEDs are red or green. DON'T DO IT! I just also bought a couple Skil cordless screwdrivers and the designers were sensible enough to have an LED that flashes in one state, solid in the other... problem solved. [/RANT]

So, unlike those Skil 4v 1/4" screwdrivers which also have 1500mah batteries, the instructions with the Bauer don't say to charge before using. They do say to not charge the batteries for longer than 5 hours or they can be damaged! I'm WTF, this is li-ion, isn't there supposed to be overcharge protection circuitry built in??? Says to charge 3-5 hours. I'm looking at this thing and can't tell if it's turned red yet. Probably will never know for sure. My Canon ELPH 100S camera has the same problem. The charger has green/or/red LED that drives me nuts.

Now, I have the charger for this Bauer cordless screwdriver plugged into my Kill-a-Watt and it's showing 118v, and when I switch it was show Watts, it goes between 2 and 3. How can this thing charge a 1500mah battery pack in 3-5 hours only drawing 2-3 watts?

cuz wall is 120 vac and that battery is probably 3.6VDC

 

[Muse]

cuz wall is 120 vac and that battery is probably 3.6VDC

Well, it's advertised as a 4v tool. The wall wart (which draws 0 watts according to the Kill-a-Watt when not attached to the tool) says it's 10 watts, but delivers 5v DC at 500mAmps.

Still doesn't explain to me how a 1500mah battery system can be fully charged in 3-5 hours by a wall wart drawing only 2 watts (according to the Kill-a-Watt).

Now, the crazy thing is I just looked over at the screwdriver and the LED was dark (this after initial charging of ~2 hours, don't know the extent of charge it shipped with). So, the manual lied. After fulling charging the LED goes OFF. WTF! Kill-a-Watt showed 0 watts being drawn.

 

[sdifox]

Well, it's advertised as a 4v tool. The wall wart (which draws 0 watts according to the Kill-a-Watt when not attached to the tool) says it's 10 watts, but delivers 5v DC at 500mAmps.

Still doesn't explain to me how a 1500mah battery system can be fully charged in 3-5 hours by a wall wart drawing only 2 watts (according to the Kill-a-Watt).

Now, the crazy thing is I just looked over at the screwdriver and the LED was dark. So, the manual lied. After fulling charging the LED goes OFF. WTF! Kill-a-Watt showed 0 watts being drawn.

500mAh*3 = 1500mAh....

 

[Muse]

500mAh*3 = 1500mAh....

Well, 500ma at 5v, but why is the WW drawing just 2 watts?

 

[sdifox]

Well, 500ma at 5v, but why is the WW drawing just 2 watts?

Sigh... Your wall is 120VAC, output is 5VDC... Switching power supply are like 80-90% efficient.

 

[Red Squirrel]

Probably just lot of inefficiencies in conversion process. The power factor may also be completely out of whack as for such small devices it's often not seen as critical.

Is it one of those big heavy wall warts, like with a big transformer? It may even be a linear power supply.

 

[sdifox]

Probably just lot of inefficiencies in conversion process. The power factor may also be completely out of whack as for such small devices it's often not seen as critical.

Is it one of those big heavy wall warts, like with a big transformer? It may even be a linear power supply.

Lol no. Switching power supply are dirt cheap and efficient.

 

[Jon-T]

1500 mah at 3.6v is 5.4 watt hours

and you wonder how it can be charged in 4 hours using ONLY 2.5 watts (10 watt hours off electricity)?

 

[snoopy7548]

1500 mah at 3.6v is 5.4 watt hours

and you wonder how it can be charged in 4 hours using ONLY 2.5 watts (10 watt hours off electricity)?

Old people don't understand fancy things like voodoo wall warts and numbers.

 

[sdifox]

Old people don't understand fancy things like voodoo wall warts and numbers.

In grade six I hooked up a wire on nail electromagnet to a two blade prong plug and plugged it into the socket.

Blew out the WWII era school's fuses. I only got blackened finger but the blades evaporated.

 

[Muse]

Probably just lot of inefficiencies in conversion process. The power factor may also be completely out of whack as for such small devices it's often not seen as critical.

Is it one of those big heavy wall warts, like with a big transformer? It may even be a linear power supply.

That charger isn't what I'd call a power supply. It's just a charger of the li-on battery system in the screwdriver. It's quite small and the fact that it draws (according to the Kill-a-Watt, whose accuracy at low watts is something I have doubted before!) zero watts when not connected to the screwdriver indicates it is no transformer but a solid state AC--->DC and voltage conversion device.

It just seemed to me that 2 watts wasn't enough to account for a full charge in 3-5 hours for a 1500mah battery system and that may be the source of my confusion.

The fact that the instructions said it would turn red when charged and that I never saw that (well, I AM colorblind) and that the charging system actually shut down is just plain strange.

 

[Muse]

1500 mah at 3.6v is 5.4 watt hours

and you wonder how it can be charged in 4 hours using ONLY 2.5 watts (10 watt hours off electricity)?

Yup, I just don't have a grip on the simple EE here, sorry. I need to brush up.

 

[Muse]

In grade six I hooked up a wire on nail electromagnet to a two blade prong plug and plugged it into the socket.

Blew out the WWII era school's fuses. I only got blackened finger but the blades evaporated.

I used to do that (maybe 7-8th grade) but to a great big dry cell. Had fun making motors from scratch.Built all kinds of radios from kits, too. Didn't mess with AC! I guess I heard it can kill you. I did play with DIY rockets and DIY explosive powders. I stopped doing that when one device ignited accidentally and scared the shit out of me.

 

[Red Squirrel]

I started messing with mains AC at like 10ish lol, but I think I had it in me since I was a toddler since at like 2 years old I pulled on a switch in the fridge with my mouth and it shorted out in my mouth. It was the switch for the light inside, and pretty sure it was using line voltage at the time. Now days it's probably a relay.

I was basically a kid version of photonicinduction. "I wonder how many 9 volt batteries this 3 volt motor can take?" was how I rolled. Everything ended with trying 120vac.

 

[Muse]

I've always respected 120v AC, it's one reason I'm alive.

I read up on SMPS's last night:

Switched-mode power supply - Wikipedia

en.wikipedia.org

Man, that's some complex stuff, and I mean, yeah, you gotta be basically an EE to dig what's going on there. I wasn't completely lost or I never would have stayed with it a good hour. Finally I was too tired and my eyes hurt.

So, yeah, I guess the PS battery charger for that Bauer cordless drill has a rectifier stage (well, obviously) and it must be a very small transformer (?). I should have realized that 2.5 watts AC over 3-5 hours should charge that device. It's clear to me now.

I was aware that they've made great strides in wall warts over the years, I have a giant box of them in my workroom. Never know when you might need an AC-->DC 9v 500mamp wall wart, etc. etc. Several times I've been glad I didn't discard my PS's. I am using one to keep me cool in the warmer months, powering a couple of 200mm silent case fans mounted in my bedroom window. Sure beats a roaring energy glut room air conditioner. Those fans run on nearly zero energy in comparison.

 

[sdifox]

I've always respected 120v AC, it's one reason I'm alive.

I read up on SMPS's last night:

Switched-mode power supply - Wikipedia

en.wikipedia.org

Man, that's some complex stuff, and I mean, yeah, you gotta be basically an EE to dig what's going on there. I wasn't completely lost or I never would have stayed with it a good hour. Finally I was too tired and my eyes hurt.

So, yeah, I guess the PS battery charger for that Bauer cordless drill has a rectifier stage (well, obviously) and it must be a very small transformer (?). I should have realized that 2.5 watts AC over 3-5 hours should charge that device. It's clear to me now.

I was aware that they've made great strides in wall warts over the years, I have a giant box of them in my workroom. Never know when you might need an AC-->DC 9v 500mamp wall wart, etc. etc. Several times I've been glad I didn't discard my PS's. I am using one to keep me cool in the warmer months, powering a couple of 200mm silent case fans mounted in my bedroom window. Sure beats a roaring energy glut room air conditioner. Those fans run on nearly zero energy in comparison.

Eh? Computer power supply have been switched mode since the 80s, maybe even earlier.

 

[Muse]

Eh? Computer power supply have been switched mode since the 80s, maybe even earlier.

Never said they weren't.

More sophisticated, I suppose, than the wall warts around in the 20th century. Those were bigger than what I'm seeing now and they stayed warm (i.e. drew significant watts) even when not plugged into working devices. The new ones seem to draw nothing in that state, a big change.

 

[WelshBloke]

I've always respected 120v AC, it's one reason I'm alive.

Come play with our 240v stuff!

I remember rewiring some wall lights in an old Victorian house i lived in once. I assumed that the wall lights were on the lighting circuit so I'd turned that off at the fuse box.
I remember going up the ladder and tinkering with the fitting, then I remember a "NNNNNNNNGGGGGGGGGG" sort of feeling and finding myself on the floor next to the ladder.

I stopped making assumptions about house wiring that day.

 

[sdifox]

Come play with our 240v stuff!

I remember rewiring some wall lights in an old Victorian house i lived in once. I assumed that the wall lights were on the lighting circuit so I'd turned that off at the fuse box.
I remember going up the ladder and tinkering with the fitting, then I remember a "NNNNNNNNGGGGGGGGGG" sort of feeling and finding myself on the floor next to the ladder.

I stopped making assumptions about house wiring that day.

In the house I lived in Buenos Aires, the fuse box was covered with a piece of marble. It was very humid that day and I got shocked touching the marble , not even trying to open the box, just happened to put my hand on it.

 

[WelshBloke]

In the house I lived in Buenos Aires, the fuse box was covered with a piece of marble. It was very humid that day and I got shocked touching the marble , not even trying to open the box, just happened to put my hand on it.

At least you got shocked doing the right thing, I got shocked for being an idiot!

Not that that matters if you actually get electrocuted!

 

[sdifox]

At least you got shocked doing the right thing, I got shocked for being an idiot!

Not that that matters if you actually get electrocuted!

I installed a 240VAC 30A breaker in the box without turning off the panel breaker

That wooden enclosure is where the 200A panel is.

 

[WelshBloke]

I installed a 240VAC 30A breaker in the box without turning off the panel breaker

That wooden enclosure is where the 200A panel is.

View attachment 30546

OK you got shocked that one time for doing the right thing!

 

[sdifox]

OK you got shocked that one time for doing the right thing!

I grew up in an electronics parts retailer/distributor :awe:

 

[Muse]

Come play with our 240v stuff!

I remember rewiring some wall lights in an old Victorian house i lived in once. I assumed that the wall lights were on the lighting circuit so I'd turned that off at the fuse box.
I remember going up the ladder and tinkering with the fitting, then I remember a "NNNNNNNNGGGGGGGGGG" sort of feeling and finding myself on the floor next to the ladder.

I stopped making assumptions about house wiring that day.

Yeah, in my house it would be stupid to make assumptions about the wiring. Built in 1910! When I go up in the attic I have to be careful where I put my feet. The naked wires are all over. Knob and tube old fashion wiring, and who knows what modifications were made by who? I assume everything's powered until I know for sure it isn't. Mindfulness helps in this. I've done a little wiring here. Intend to put in a lamp in my pantry, which is on my to do list, another is needed in there. I have the parts, just have to do it. The whole house should probably be rewired, however nothing's prodding me, there's no pressing reason to do it, things are working and I am using a lot less juice than this house has used in the past.

My outlets are grounded type outlets with the grounding pin, but the wiring isn't grounded! I've installed maybe 2 DIY grounding wires, attached to pipes or whatever just to get some protection, but the wiring is substandard and appliances aren't properly grounded except maybe when plugged into a couple of my outlets.

There's a tankless water heater and the installers ran a special service to it. I suppose that's grounded properly, but I'm not certain. I should test that. They put in an outlet out there, a box for external access to AC that I should test. Not that it would effect all my other boxes...