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Replacing a Lithium Battery...

DavidMil

New Member
I recently purchased a LinkMicro LM208 digital microscope. It has a 8.5" LCD screen that has an resolution of 1920 x 1080. It also has
eight LED's around the lens of the scope, and two very bright LED's on flexible stalks. It also uses a 32 gig TF memory card to record
your work.
Here is the problem... all of this runs off of a single ICR 18650 3.7 volt, 2200mAh battery with no outside way to power the scope. The result
of this is the battery shuts off after about 20 to 30 minutes and I have to pull it out to recharge it. It is getting very old to work for 30 minutes,
pull the battery out, and then wait for the battery to recharge. I don't care if this voids the warranty, but is there a AC to DC power supply that
I can use instead of the battery? I have some 9/16 wooden dowels and was thinking about cutting off a piece and attaching the leads from the
power supply to the ends of the dowel and then inserting the dowel into the battery socket. This may sound crazy but it's past the 30 day return
period and I'm mad enough at this point to put the scope out with the garbage. I'm open to suggestions (other than "don't try that")!

DavidMil
 

rjenkinsgb

Well-Known Member
Most Helpful Member
Something like this should be suitable:

You need to adjust the output voltage to somewhere around 3.8V before connecting it to the microscope.
The battery range would be 4.2V fully charged down to around 3.3V flat, so somewhere mid range in that should be fine.

The power supply to that module can then be a generic 12V 2A one or laptop (16V - 20V) power adapter or whatever is convenient, just use one rated 20W or higher.

I'd estimate the microscope actually uses between 3 - 4A from the battery life you give, but the PSU modules sold on ebay are often rated at their short-term max value (or something guessed) so I'd always pick one with at least twice the current rating you need, hence a supposed 10A type.
 

audioguru

Well-Known Member
Most Helpful Member
Is it possible that your battery is a no-name-brand fake?
Here is one of many videos when an 18650 battery was cut open to reveal lots of rice flour and a tiny little real battery:
 

DavidMil

New Member
I think that audioguru might have hit on something here! After reading his post I went up the street to Best Buy
and bought another battery. The weight difference is significant: The Doublepow battery (that came with the scope)
weights .825 oz and the battery that I got from Best Buy weights 1.57 oz. A difference of .745 oz. Almost twice as heavy
for the same milliamp hour rating. The new battery is still charging, so when it finishes I'll plug it in tomorrow to see
how long it lasts. I want to thank both of you for responding to my question, and I'll let yo know what the results are
tomorrow evening.

Thanks again!
David
Kingwood, Texas
 

audioguru

Well-Known Member
Most Helpful Member
Sometimes a new fake battery has lead in it instead of battery chemicals. I hope your new battery is a Name-Brand, but even a Name can be copied.
 

DavidMil

New Member
Ok, other problems... The new battery ran the scope for 1.5 hours before the scope said low power and shut off.
I pulled the new battery out and recharged it. The second time I tested the scope it only powered the scope for 45
minutes before the low battery message appeared. The original battery never had a reduced time before low power,
always about 30 minutes (even after six recharges). Now the new battery is hung up on 33 minutes between full and
low battery messages. The charger I am using is: Eastshine Company Smart S2 Charger. It is made for my battery and
give a continuous readout of Voltage, amperage, and time. It has a automatic shutoff when the battery is charged also.
I tested the battery with my meter and it says that I have a little over 3 volts left in the battery. So what I did was stuck
an LED on the battery to drain it down a lot more. I'm recharging it now and I'll see if this makes any difference.
Could it be that the scope needs more power than this battery can provide? Which would go back to original idea
of replacing the battery with an external power supply...

DavidMil
 

audioguru

Well-Known Member
Most Helpful Member
Is the new battery 2200mAh or more?
Is it a good quality Name Brand or a cheap no-name-brand copy?
Does the charger charge it to 4.2V then leave it at 4.2V for about 1 hour before the charger says it is fully charged and shuts off?
 

DavidMil

New Member
The new battery is a Panasonic NCR 18650 2200mAh. No, as soon as it hits 4.2v the charger shuts off.
It took 4.23 hours to charge the battery this time.

David
 

rjenkinsgb

Well-Known Member
Most Helpful Member
No, as soon as it hits 4.2v the charger shuts off.
It sounds like you need a better charger - when the battery first reaches 4.2V, it's only around half charged.
The charger should hold it at that voltage until the charge current has reduced to a very low level.

More info here:
 

audioguru

Well-Known Member
Most Helpful Member
As soon as a Lithium-Ion battery reaches 4.2V then its charge is a long way from being fully charged.
Panasonic is a good quality Name-Brand. Did a Chinese copycat spell Panasonic wrong? Panawrongic?
 

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audioguru

Well-Known Member
Most Helpful Member
Panasonic bought Sanyo who made pretty good batteries for years. They also made those awful hybrid amplifier modules.
Have you seen no-name-brand Chinese ICs with the map of Texas in the logo, upside down?
 

DavidMil

New Member
When the Chinese copy something they go all the way. New chips that I have had to buy from
the Chinese because you can't get them anywhere else, ever go so far as to have the original
dates of manufacture on them: A very nice new 300 baud modem chip that I got from China has a
manufacture date of 8327 stamped right next to the TI logo. And right below that it has Philippines
as plane as day...

David
 

DavidMil

New Member
Back on subject...
This scope was designed by a 6 year old (I think). If you turn the PC on first and then use it
to turn on the scope via the USB cable, the scope will run off USB power and not the battery.
If you use the power button on the scope to turn the scope on it runs off the battery regardless
of the whether the PC is powered up and the USB cable connected. Also if you turn off the eight
LEDs around the digital scope it will run for over an hour before getting a low battery message.
The two super bright LEDs on the stalks are run off of USB power and don't draw power from the
battery under any circumstance. And one more thing... If you use the PC to power up the scope,
it will trickle charge the battery while the scope is on (takes about eight hours to charge it that way).
I have work arounds now, and I think I've bent you ears long enough. Again I want to thank all for help
and suggestions!

Stay safe in these strange times!
David
 

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