FLUKE 8050A searching adjusting tip to set DC at 0000

[Kiriakos GR]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

Thanks for the multiple warnings, now pay the proper attention to the post #16.
And as last info I will add that this battery setup does not even get warm, and actually the batteries stays frozen all the time, something that does not happen when my mobile phone charges it 3.7V battery with 300mA or more.
That makes a 900mA battery to be ready in a hour time.

Back to class for a Math lesson: 300mA for a single cell VS 240mA for two Cells.
All the bets goes that my phone will explode first !! LOL

[tom66]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

It's nothing to do with warmth! Well, not initially.

It's to do with the potential for the voltage to rise above rated limits, without a constant voltage limiter!

If this happens then the battery rapidly becomes warm, potentially starting a fire.

As much as you may think you know, you apparently do not know anything about battery safety.

[budm]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

http://www.edn.com/design/power-mana...ing-and-safety
"The main challenge in charging a Li-Ion battery is to realize the battery's full capacity without overcharging it, which could result in catastrophic failure. There is little room for error, only ±1%. Overcharging by more than +1% could result in battery failure, but undercharging by more than 1% results in reduced capacity. For example, undercharging a Li-Ion battery by only 100 mV (-2.4% for a 4.2-V Li-Ion cell) results in about a 10% loss in capacity. Since the room for error is so small, high accuracy is required of the charging-control circuitry. To achieve this accuracy, the controller must have a precision voltage reference, a low-offset high-gain feedback amplifier, and an accurately matched resistance divider. The combined errors of all these components must result in an overall error less than ±1%."
http://batteryuniversity.com/learn/a..._ion_batteries
So if you use simple constant current charging circuit to charge Li-ion and not terminate the charging, you will find out sooner or later what will happen. Proper charger for Li-ion is a must.

"Li-ion cannot absorb overcharge, and when fully charged the charge current must be cut off. A continuous trickle charge would cause plating of metallic lithium, and this could compromise safety. To minimize stress, keep the lithium-ion battery at the 4.20V/cell peak voltage as short a time as possible.
Once the charge is terminated, the battery voltage begins to drop, and this eases the voltage stress. Over time, the open-circuit voltage will settle to between 3.60 and 3.90V/cell. Note that a Li-ion battery that received a fully saturated charge will keep the higher voltage longer than one that was fast-charged and terminated at the voltage threshold without a saturation charge.
If a lithium-ion battery must be left in the charger for operational readiness, some chargers apply a brief topping charge to compensate for the small self-discharge the battery and its protective circuit consume. The charger may kick in when the open-circuit voltage drops to 4.05V/cell and turn off again at a high 4.20V/cell. Chargers made for operational readiness, or standby mode, often let the battery voltage drop to 4.00V/cell and recharge to only 4.05V/cell instead of the full 4.20V/cell. This reduces voltage-related stress and prolongs battery life."
"Overcharging Lithium-ion

Lithium-ion operates safely within the designated operating voltages; however, the battery becomes unstable if inadvertently charged to a higher than specified voltage. Prolonged charging above 4.30V forms plating of metallic lithium on the anode, while the cathode material becomes an oxidizing agent, loses stability and produces carbon dioxide (CO2). The cell pressure rises, and if charging is allowed to continue the current interrupt device (CID) responsible for cell safety disconnects the current at 1,380kPa (200psi).
Should the pressure rise further, a safety membrane bursts open at 3,450kPa (500psi) and the cell might eventually vent with flame. The thermal runaway moves lower when the battery is fully charged; for Li-cobalt this threshold is between 130–150C°C (266–302°F), nickel-manganese-cobalt (NMC) is 170–180°C (338–356°F), and manganese is 250°C (482°F). Li-phosphate enjoys similar and better temperature stabilities than manganese.
Lithium-ion is not the only battery that is a safety hazard if overcharged. Lead- and nickel-based batteries are also known to melt down and cause fire if improperly handled. Nickel-based batteries have also been recalled for safety concerns. Properly designed charging equipment is paramount for all battery systems"

No way I will put Li-ion in place of Ni-Cad and sign off the paper and give that equipment back to customer.
"I did test this setup for two days, I can almost sign an warranty paper that this setup is truly capable even for 9 hours operation." Safety, what safety! LOL.

[budm]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

If you look at the charging circuit, it is real simple constant current source charging. The U26 (LM317?) voltage regulator is setup as constant current source, not PULSE CHARGING. The charging current is 1.25V/9.1 Ohms = 137mA (Power switch is off, but the power supply is still running to charge the batteries when the meter is OFF) output voltage will be the Vdc on the input of U26- Vdrop across the U26. When power switch is activated, the 12 Ohms resistor is in parallel with the 9.1 Ohm to increase the constant current.
The simple DC-DC converter is made to work on 4.8V, when you use 7.2V, the output from the converter will be higher than design, better verify.
Per post 10 "While the meter uses 130 - 140mA at normal operation, at charging is capable for 200 - 240mA ( measured by Fluke 28II). " that is not the charging current you are testing since the power switch is not in the OFF position, the total current is split into the batteries and the circuits' current draw. The constant current of 1.25V/5.1 Ohms (Notes: 9.1 Ohm in parallel with 12 Ohms = 5.1 Ohms) = 240mA when the power switch is on.
So after 20 Hours, you better remove the charge, since in 20 Hours the total current charge will be 2.74A (137mA x 20) that the batteries received.

[budm]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

Post 9:
"What looks interesting is the fact that even by using a lower rated 250 mA NiCD from a cordless phone, the overnight charging it killed it." Well it is being forced charge by 137mA of constant current non stop over night.

Post 14:
"The 8050A with out batteries connected at those pins there is a voltage reading as 30V.
The explanation is that the charging are made by pulses at 200Hz."
The filter cap (C23, 2200UF/16VDC) voltage rating for the power supply is only rated at 16Vdc, that 30V reading cannot not be right.
And no pulse charging either, just plain 137mA constant current source with not output voltage regulation.
If the charging is that simple, they will be selling simple power supply with LM317 setup as constant current source real cheap without any safety concern.

Learn more about charging Li-ion from Ti and what you can build:
https://cdn.badcaps-static.com/pdfs/...28646f4d3a.pdf
https://cdn.badcaps-static.com/pdfs/...db77cdc5e1.pdf
https://cdn.badcaps-static.com/pdfs/...713ab6a725.pdf

[Kiriakos GR]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

Interesting amount of comments but with out value to me.

The 200Hz is printed on the PCB next to the pins for the battery, blame FLUKE that wrote something inappropriate on it.
Thankfully I do own an Oscilloscope those days and I did see this pulsing with my eyes.

Thin Li-ion batteries for cell phones, I am challenging any one about getting in to the process to dismantle one of them.
A strip of copper + a strip of aluminum + a bit of active chemistry in the form of dry paint, and all those elements packed up by a nylon heat-shrink ed bag.

My last word about those very small in power Li-ion batteries is that they look capable to tolerate some soft abuse which it can also caused even by a regular
mobile phone charger which has been out of the tight specifications since when was new.

Improvising about the use of materials made for some other use, it is safe only for the person who has the experience and knowledge to examine and test any parameter of danger up-front.

I am not seeking for any public approval from any one, but if there is any people out there with more opened views than the Google search engine, they might find my approach as interesting. :-)

[budm]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

You are seeing the harmonics of the DC-DC converter.
"The 8050A with out batteries connected at those pins there is a voltage reading as 30V." You better check your way of measuring the circuit also, or read the diagram."

"Interesting amount of comments but with out value to me." We all know that your are an expert in batteries.
Yes you know so much that you kill the batteries:
"What looks interesting is the fact that even by using a lower rated 250 mA NiCD from a cordless phone, the overnight charging it killed it."
"Improvising about the use of materials made for some other use, it is safe only for the person who has the experience and knowledge to examine and test any parameter of danger up-front. "

"more opened views than the Google search engine" Any more open view than Ti documents?
By the way, that Nokia batteries has third pin for temp monitoring if the temp gets too high, the charging will be terminated, but you are not using that pin, so good luck.

[Kiriakos GR]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

"Interesting amount of comments but with out value to me." We all know that your are an expert in batteries.

a) Oh thanks for pointing out the world We it translates that you are part of one imaginary army.
b) I am as person an more intelligent temperature monitor than a thermal sensor of 0.20 $.
c) I do not use luck in my life, this is why I do not even play the Lotto game.

Either way I do appreciate your contribution in this thread.

[budm]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

"I am as person an more intelligent temperature monitor than a thermal sensor of 0.20 $.'
Sure you are, LOL.

[tom66]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

You also don't understand how a mobile phone charger works.

The AC adapter only supplies 5V +/-5% though at the end of the cable it can be as low as 4.5V.

The charge management IC (often integrated into the power management IC) uses a linear regulator or a DC-DC buck converter to precisely charge the cell, for maximum capacity BUT ALSO with safety in mind. It will not allow the battery to exceed 4.2V and it will also monitor the internal temperature of the cell and disconnect or limit charging at high temperatures. Also, it will not let the cell go below 2.7V and it will make sure to count the energy going in and out of the cell to estimate lifetime of the battery.

Doesn't matter WHAT you give the phone, as long as it is within its acceptable range it will charge and the safety of the cell will be maintained. If it is outside of that range it will stop charging. (Obviously too high voltage will damage the phone but within limits it will work.)

[budm]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

Safety, what safety? "I am as person an more intelligent temperature monitor than a thermal sensor of 0.20 $." I am sure he monitors the temp while he is sleeping with the charger plugged in over night ans also the meter that he signed off on it.

[Kiriakos GR]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

budm when you will update your ID from Knowledge Seeker to a Pro ( in 10 years) ,
then I will take you more seriously, for now you are just a kid playing with it keyboard.
By my opinion you do not own even half than the understanding of Tom regarding electronics.
From the other hand Tom goes by the book due his limited experiences which he will improve in time,
those additional experiences they will help him to improvise too by using the limits of hardware with out causing a disaster.

[budm]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

Do you why? Because you can never stop learning, not like you that pretends to know it all. So you know so much, you kill the batteries because you know so much about charging them. Did you look at the diagram and know how to calculate the constant current output from that circuit? No, would be my answer.
"now you are just a kid playing with it keyboard." Is that the best you can come up with?
"By my opinion you do not own even half than the understanding of Tom regarding electronics."
Lets ask the people in the forum, shall we?
Any one can put the word 'PRO' on the ID, so?
Is this the work of kid with a key board? This one is single channel Power relay controlled through the web from any where in the world.

[tom66]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

Some stuff I've made

http://www.batteryshowdown.com/ - Recently featured on Channel 4 prime time television in the UK. (That's about 5.2% of UK viewers) Uses an opamp to regulate discharge current, power dumped in two FETs. Look at the schematic file, if you want to see how it works. I made the website and firmware, too.

http://www.bitbox.co.uk/news-item/te...-spirit-level/ - Coolest business card ever. Built in electronic spirit level. Based on STM8 microprocessor and accelerometer. Low cost to manufacture.

Both made while working in an internship with only elementary secondary school education. From design of schematic, layout of PCB, to manufacture. And they both worked first time!

In addition I have developed my OSD at age 16 (3 yrs ago!) which is a fully graphic video overlay generator for model aircraft based on dsPIC microcontroller (still trying to find the time to pull that into production.)

When I come back I finish my work on an audiophile/audiophool headphone amplifier which needed a cheap battery charging solution (PCB done, but I left before they could be manufactured.) I designed a NiMH charger based around an LM317, because if you need to make the charger cheap/simple, then NiMH is the way. It's a lot harder to blow up a NiMH, especially if you regulate the current.

That thing looks nice Bud! Any more projects/products to share?

[budm]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

Thanks, cannot show too much, too many competitors out there. I am part of the design teams that has over 100 models out in the field since 1975.
"By my opinion you do not own even half than the understanding of Tom regarding electronics"
But again, what do I know, I do not have 'PRO' on my ID tag.

"budm when you will update your ID from Knowledge Seeker to a Pro ( in 10 years) ,
then I will take you more seriously, for now you are just a kid playing with it keyboard."
So every one, make sure to put 'PRO' on your ID, otherwise Mr. G will think you are just a kid on the keyboard and will not take you seriously.

[Kiriakos GR]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

No one said that the posters in this thread they do not have and their bright side,
the idea behind a successful communication in a forum is the different point of views.
That works as salt & pepper and makes the conversation to taste better.

From the other hand the proper way to evaluate and measure up your "talent" is just one,
and comes from the answer in the question: Which is the price of the most expensive item that a customer trusted in your hands so to repair it?
While I do not have any need for self promotion due the Internet, I can proudly say that it was cost 600,000.00 Euros. ( Industrial system)

Now it is time to return back to topic, and I will say thanks for all the received comments.
My idea works well for five days, if something goes wrong in long term, I will return back and add this info too.
I am not afraid to admit my mistakes if something goes wrong and I have prove that all ready.

[budm]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

"then I will take you more seriously, for now you are just a kid playing with it keyboard."
So why did you post that as an insult?
"While I do not have any need for self promotion due the Internet, I can proudly say that it was cost 600,000.00 Euros. ( Industrial system)" See? you are bragging again. I worked on Ion-implanting machine in 70's which was over a million dollars at that time when I was working at Fairchild Semiconductor. I never bring it up on how expensive the equipmemt I worked on until now since you bring it up, so stop bragging, you're not impressing anyone here, by the way learn how to read schematic before making any more modification.
One day some one will get hurt due to your carelessness due to your modification. Look at Boeing's batteries problem, some experts did not pay attention, luckily no one got hurt. French design charger system, Japanese batteries, US test and verification and it still failed. "I am as person an more intelligent temperature monitor than a thermal sensor of 0.20 $." sure.

[Kiriakos GR]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

"
One day some one will get hurt due to your carelessness due to your modification.

Oh really? I feel all ready as an extremist with a mini nuclear bomb in my hands.
I have the feeling that you are dieing to attract my attention, with your pointless arguments.

Also when one real professional tests a circuit for 24 hours before posting any info, you have two choices a) accept the results or b) Ignore it.
This what the smart people do.

My advice move away from this thread, you are looking as Troll all ready in my eyes.

[budm]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

Getting upset, aren't you?
"My advice move away from this thread, you are looking as Troll all ready in my eyes." Really?
It is getting funnier every minutes. Better come up with better insult!

[Kiriakos GR]

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

Getting upset, aren't you?
"My advice move away from this thread, you are looking as Troll all ready in my eyes." Really?
It is getting funnier every minutes. Better come up with better insult!

Post Read & Ignored.