#66 - Fluke 99 Li-ion charging mod 

Cool video and modification. These things do take time, especially to confirm they are safe and don't overcharge your lipo pack. One tip though: when checking the final charge voltage, it might have been less time consuming to connect a decent capacitor instead of the battery, it charges up quicker and you could safely and quickly see the result of your adjustment. For setting the current you need to connect the battery again as it pulls current for a longer time to aid measurement.

Thanks for this excellent preparation for this batterie/charging option. I just modified my Fluke 92 and it seems to work. I used two 18650 standard LI-Ion cells, the only difference for the charging current in the 92 model is that it has only one 1 Ohm resistor without the 10 Ohm resistor. To be sure I solder a 0.75 Ohm resistor parallel. At this time the charging current is about 75mA but the cells are quite fully charged. I must test it a little bit more. Again many thanks for this description. Take care 🏆 👍

Great example of practical battery upgrade and adaptation of the charging circuitry.

Glad you’re back. Missed your videos. They’re great.

Nice to see a news video, thanks for sharing this, your content is always very interesting !

I really enjoy your video's when I think of a question to ask, you answer it in the video. I see modding old equipment just means you can keep them longer with new functionality. I'm going to start calling you the MOD MAN but no you do so much more. Cool video look forward to the next one *_CHEERS_*

The Scopemeter was one of Fluke's first collaborative effort with Philips. Philips did much of the hardware and software design on the two original models.

welcome back! Hope to see more equipment repairs. Those were excellent series.

Nice work! Another possible solution is to use LiFePo4 battery pack which has a little bit lower voltage and much more charge/discharge cycles (which makes it best replacement) :)

Great timing! I've got a Fluke 99 arriving soon and was thinking of this same modification.

great to see you back! i almost forgot who's channel it was when the note popped up lol

Thanks! This is great. I'll add these mods to my Fluke 97 with the Li-ion pack I added a few months ago. Out to buy resistors later this week.

Cool video!

Thanks, this is a perfect example of what RU-vid DIY videos should be about. Do you remember the Lipo cell sizes you used? They seemed to fit perfectly and I fear I will purchase the wrong size and have to reorder.

Those fins on the cover are a real concern with Li based packs. They look sharp enough to damage the battery pack. Maybe 3D print a cover with differently shaped reinforcement in that area? At least a reinforcement of the pack with a plastic glue, for time being

Great result.

interesting project. Clever idea.

Excelente aporte, tengo uno igual y me lo vendieron sin batería, vamos a ver como queda con tu modificación. Saludos desde Perú

I have a fluke 105b that stopped charging I was wondering if you be able to help me with It seems to be missing the 8v for the meter when plugged in

Hi, if you are familiar wiith Noise Sources for Noise Figure measurements. I need to know what is the recomended ENR in dBs of the source in order to measure accurately NF of amps with less than 1 dB NF and if you know how to calculate that. Thanks you and great channel

Hello . I am new to civil electronic repair and plan to buy Fluke 99 at this time, should you advise me? Thank you .

Dear Sir thank you for your sharing. I have a fluke 99B scope. Unfortunately, the electronic board burned out because we gave reverse voltage. I can't repair it. If you have, can you send me the electronic board diagrams? or can you tell me the models of the materials on the electronic board.

Please send me the circuit digrams. I am searching for a long time

I've been told that Lithium lasts MUCH longer if you only charge to ~90%... Perhaps change Vchg to 8.3V...?

How many amps do you suppose these ScopeMeters draw? Mine kills batteries pretty fast. I'm in the process of building one of your LiPo battery packs, but it seems like this guy suffers from a power demand that's too high. With the regular C cells power lasts for less than 5 minutes.

Hi. Please tell me. Is it possible to supply 8.4 Volts to the input of the battery compartment. I want to use two 18650 batteries in series. I will charge them separately from the device. 8.4 Volts not dangerous for the device?

It looks like you are using a different battery management module here than on the Fluke 97 video. Could you post the model of the BMS module?

Hello, excellent modification. Do you still have by any chance stl file for the cover? thanks

Buenas tardes. Yo tengo uno igual pero la pantalla está muy quemada. Cómo puedo restaurarla ?

Hello 3. ;-)

Hi sir I need pm 97 LCD display

Now that I have a 3D printer I've been fixing all my lost and broken parts, so I would make a new door.

awww, would love to do that to my fluke 123 ( old one )

Mr feedback loop do you have a facebook account?

Hello 2