HobbyKing Battery Medic

[Functional Artist]

I picked up a battery cell checker/voltage meter called the HobbyKing Battery Medic, to help monitor the individual cell voltages, in my Lithium batteries.

They are designed & made for use with/in small RC (remote control) vehicle Lithium battery packs (cars, airplanes, drones etc.)
...but, a Lithium battery cell "is" a Lithium battery cell
...& voltage "is" voltage.

Here is a video with some info on these little meters

 

[Functional Artist]

I wired up a "pigtail" to connect the meter, to a 6S 24V Chevy Volt Lithium battery module
...& started checking out it's features
...& understand how it works

 

[Functional Artist]

While working with/using the Battery Medic, I noticed that it showed the last cell (#6) to be ~ .05V "off"
(which doesn't seem right, these cells/modules usually stay pretty well balanced)

So, I used the (red) multi meter to double check the voltage readings, of the 1kWh 24V 45AH module
...& it said the voltage of the cells, were all much closer (within ~.02V)

Then, I triple checked with the (orange) meter
...& it also showed the voltage of the cells, to be much closer too (within ~.02V)


Next, I tried the Battery Medic on another 1kWh 24V 45AH module
...& it also, showed cell # 6 to be "off" or unusually higher than the other cells.

Then, I tried it on the (2) 1kWh 24V 45AH modules that power my Hell-raiser kart
...& it also showed cell # 6 to be higher than the others, in both modules.

Hmmm...defective?

 

[Functional Artist]

I picked up a couple of Battery Medic clowns (clones, I mean clones)

Hehe, a Chinese clone of a Chinese product, I bet the Chinese are really pizz'ed, at themselves

I'm happy to report that they (both) seem to be more accurate, than the original

I also, made up a "double connector" to connect (2) cell checkers to a 12S 48V batt module

 

[madprofessor]

Should it be assumed those are just for checking in the shop, not while driving? My Magoo eyes would never be able to read those in the glaring sun while they vibrate on the steering wheel or wherever.

 

[Functional Artist]

Should it be assumed those are just for checking in the shop, not while driving? My Magoo eyes would never be able to read those in the glaring sun while they vibrate on the steering wheel or wherever.

Hey Mad,
Yes, they are mainly for "in shop" use
...or can even be used for quick checks "in the field" (if an issue is suspected)

Most of the time, you really don't need to "constantly" monitor the pack, at the "cellular level" (unless there is an issue)

It's just that monitoring the individual cells of a battery pack is the best way to know what's "going on" in there
...& it's so much easier to do this, when you can just "plug in" a little meter
...& not have to "pop" the top off the battery pack
...& check each & every cell, one-at-a-time

The voltage level of "all" the cells, in a pack, should (ideally) be really close
...so, they "all" re-charge & dis-charge evenly

The balance function is to help "even" the voltage levels out (if they "drift")
...& the dis-charge function is for dis-charging a pack down to a "safe" level (like for storage)
The modules I have been working with are a bit "too big" to use those additional functions (probably overheat its wittle wesistors)
...so, the plan is to just use them for "easy" periodic monitoring.

 

[madprofessor]

F.A., have I thanked you lately for all the stuff I'm learning about batteries and controls from you?

 

[Functional Artist]

F.A., have I thanked you lately for all the stuff I'm learning about batteries and controls from you?

Hey Mad,
Your very welcome.

I too am learning, as I go (I think Sid would be very proud of the progress I've made)
...& try to share everything I learn (the good, the bad & the ugly)

That's the main reason for all of the detailed build threads
...but, also, I sometimes go back & read thru my threads
...&/or watch the associated videos, to help refresh me on how (or why) I did something.

* I have bunches of notebooks full of info
...but it's just so much easier to just look it up on here (or YouTube)
...so, I call 'em digital records

 

[Functional Artist]

Still playing with my "new" little cell checkers
...enjoying how easy they are to use
...& the additional info they provide

Here is the Digital Battery Balance Monitor that I used to use.

It simply told me what the voltage level was, in each side of the module
This info was helpful to know because "if" both voltage readings were the same, it indicated that the module was "in balance"

The "new" 3 in 1 meter's also, show what the voltage level is in each side of a 48V pack (quick indicator of a balanced pack)
...but additionally, what the individual voltage level "is" of each & every cell

Here is a bit more "use" info (in video form)

 

[madprofessor]

Now that I'm trying to recall, I only recall having seen readouts on the electric kart stuff in terms of voltages. I think as often in terms of amp draw as voltage, hence my meters of choice for 40 years have been multirange VOMMa clamp-arounds. Do any dash-mount meters for those karts read the varying amp draws when you're pushing the gas? That would tell me (in conjunction with a voltmeter) more about capacities and loads than any amount of voltage readings alone.

 

[Functional Artist]

Now that I'm trying to recall, I only recall having seen readouts on the electric kart stuff in terms of voltages. I think as often in terms of amp draw as voltage, hence my meters of choice for 40 years have been multirange VOMMa clamp-arounds. Do any dash-mount meters for those karts read the varying amp draws when you're pushing the gas? That would tell me (in conjunction with a voltmeter) more about capacities and loads than any amount of voltage readings alone.

Yes, but were talking about (2) different tools, in an electronic toolbox.

The 3 in 1 battery meter/cell checkers help to monitor the individual voltage levels "inside" of a battery pack

Whereas, an onboard power meters help to monitor the performance of a whole system (battery pack, motor, speed controller)

As for dash mounted meters, I have used the PZEM-051 power meter, with good success, on my last (4 or 5) karts.
PZEM-051 100A DC LCD Digital Panel Meter (~$17.00)
https://www.ebay.com/itm/225135097643?hash=item346b18f72b:g:SdEAAOSww~5jCEey&amdata=enc:AQAHAAAA4JUNBIxG6mAuALKV+xK+5Myc6aS1VnQhdub0rMmI4J2CKJVTVoljWZ3/fVCc6ATAcutv+oOKm+EGGntXeb5bJPiMZXwsLqm2RRKMoLoj8a1XLu38b/G/fu/Z8ePRA8aTs41KPlSHyZhBBdHZkyFGLeyMi3v4NGQIKzPfTznnZIWxMoyW2VZw2lr8gIYFBy4OpgPVqmrog/paTRa0DhYdGVeyci6apBghlEburiH0yLJLG1AIvcuxANwnnyxeNS7maab6FyZLJlX9pYHUcb1ILXZRjJVp7EII29ftvX9Bx/vr|tkp:BFBMsqaf1o9h

It displays the total battery pack voltage (upper left)
...the wattage of the components currently "running" in the system (lower left)
...the amperage draw of the components in the system (upper right)
...& has a re-settable Watthour counter that records the Watthours that have been used, out of the batt pack (lower right)

Here is an example of a PMEM-051 power meter "in use"
(power meter info starts ~3:00 in the video)

 

[Bmr4Karts]

Now that I'm trying to recall, I only recall having seen readouts on the electric kart stuff in terms of voltages. I think as often in terms of amp draw as voltage, hence my meters of choice for 40 years have been multirange VOMMa clamp-arounds. Do any dash-mount meters for those karts read the varying amp draws when you're pushing the gas? That would tell me (in conjunction with a voltmeter) more about capacities and loads than any amount of voltage readings alone.

I use this meter that shows battery volts and amps at the same time. Instant data only, no logging.

https://www.amazon.com/gp/product/B07D2X2JSH/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

For my individual cells I use some of these. I don't monitor these while driving. More so for simple after run data collection.

https://www.amazon.com/gp/product/B09P899H3R/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[madprofessor]

Video: That's exactly what I like, a side-by-side comparison of real-time volts and amps (voltage and current). If I'm willing to take my eyes off of where I'm going to look at the dash, the info flashed into my brain in half a second needs to be exactly what that meter shows.

 

[Functional Artist]

I don't really "stare" at the dash (power meter or speedo) much
...but, it's good to have that info "right there" if you need it

That's why I've been doing a lot of (dash) recordings
...so, I/we can go back & analyze the info.

Kinda like how athletes watch "game film"
...to be able to "monitor" their performance "while performing".

Because ya don't really have time to monitor, the details of a situation, while you're doing it
...but, it's great to be able to go back & take a look
...& sometimes even years later, compare those results, to other situations

 

[madprofessor]

ya don't really have time to monitor, the details of a situation, while you're doing it

Ding! The light bulb just came on. What's easiest to see and comprehend in only a split second glance at imminent death speed?
ANALOG METERS!!! A fluorescent orange needle at a 45-degree angle to the right (for example) can be burnt onto your retinas in a microsecond, and immediately understood. My eyes would have to focus on a digital readout, and my brain then have to decipher what the number means.

 

[Functional Artist]

imminent death speed

Um...I try-n-avoid "imminent death speed"
...so, Ima thinkin' my digital meters, should do just fine

 

[madprofessor]

I try-n-avoid "imminent death speed"

Yeah, but then you miss out on that exciting thunderclap as your back door slams shut.