Save Time and Hassle, Build a DIY Battery Capacity Meter, V2

[@prosperousJ]

Great Video! Version 2 is a winner! I enjoy that you put all the hiccups in your videos, shows us you're human too. I Got 32 of the 32650's with your discount code for a small solar generator build and now I'm gonna have to build one of these to test it! Keep up the awesome content!

[@sbene6439]

Finally someone is doing a real load test, with heaters! Tired of load test videos that show a led lighting up or a saw spinning up not cutting.

[@fisherus]

Dave, you don't awe me with your videos anymore. That's basically because I am still mesmerized by your "Tower of power " video!

[@BloodBlight]

I really like putting the fuse between the cells! I will be adding that to future projects.

[@LithiumSolar]

Great upgrades! I do think the original was sufficient for our purposes (not lab equipment) but it never hurts to improve.

[@dieselpowered]

Adding sense wires is a great addition

[@gkeith4120]

Thanks, lots of consideration I Made smaller size 300 amp shunt with 12v recharging internal battery and anderson connectors form harbor freight jumper cable (clamps). Put Matching anderson’s 175 connector on leftover 17 foot #2awg cables if I need to use straight jumper or use 17 foot from meter source.

[@rtmsound1877]

Very cool. I might have to build one. The other meter I need is one for solar panels. Maybe with a shorting button to measure Isc.

[@larsltj]

I also made one of these a few months ago using the exact same meter. Mine is only with 50A shunt and the box quite a bit smaller. I'm using a rechargeable 9v battery for external power to the meter. This will also light up the rocker switch to turn the meter on (edit: I saw the polarity comment) 😀. I also added a charger port to the 9v battery on the box so it's easy to charge it without opening the box every time 😀 The 9v battery is a lithium type with built in USB charger port. So I just added an extension cable and a wall port to the outside. And I used Anderson to the cables on both sides...

[@muddywatersurbanfarm2608]

Nice! I just ordered this meter. Well one model of it. I was doing some research on it and I think you can hook up 12v for the backup power for the meter. It has a range from 3v to 12v for that connection. Then you led on the switch will work.

[@BrightSparkIdeas]

Great videos, good to see someone working things out as you go along. We all make those simple mistakes with the wire, so it is good you left them in to remind us.

[@jamest.5001]

You could have drilled the nut for the gland, out a bit, for the lug to fit through, (possibly). Great work

[@luckydogfarms]

Always learn more when I watch your videos! Thanks, J

[@techsir8866]

Love watching your videos, always educational and entertaining.

[@mcasoftwaresolutions756]

Thanks David for all your responses to my emails

[@gn02020202]

The LED in your setup will be backwards because in automotive settings the switched part is expected to go inline with the positive wire, then the other side of the light goes to ground. This is because most automotive settings have the negative wire going to the frame instead of back to the battery.

[@MrOldandslow]

Excellent construction techniques! Good job!

[@jamessawyer4625]

I like the new feeder wires being a good length to reach the battery. You can calibrate the test set with a chart showing the difference fusing the I phone or the mutli meeter as reference. That will work....

[@benlyons7752]

I always enjoy your content. It is duly noted that you review comments and take suggestions. One day soon we will have some solar too. Looking at potentially using bifacial panels for my shed.

[@DavidPozEnergy]

Thanks for leaving a comment. Yes, I try to get to all of them.

[@claudemontezin911]

Looks like you're over qualified to work for the space industry. Thanks for the very professional (you're a lot neater than I am) instructions. You know, once we know where we have some voltage drops here and there and approximately by how much, it's routine to just think with that. The important is to make things work and to our own expectations. NASA and the Russians were drinking their own (recycled) pee, eating meals was not a pleasant thing, and they knew their life span expectancy will be shortened by irradiation due to poor shielding. That's their expectations. So you're doing just great David. Great job! DIY rocks!

[@loucinci3922]

Hello from South Florida. I think you could use a dremel or file on that plastic nut so the connector would have made it through the hole. Function over fashion. Looks good. Good improvements.

[@drescherjm]

I like all of the improvements. I was yelling at my PC while watching the video when you did not run the volt sense wires to the battery the last time.

[@DavidPozEnergy]

Did the computer yell back? LOL

[@drescherjm]

@@DavidPozEnergy No, but my wife wanted to know what was wrong.

[@talenttrading]

David does! Hands on, way to go!

[@davidmcclare443]

hi i have a theory that the power to the led in the switch is backwards can you test it?

[@jamess1787]

I wonder! 8v should have been enough to get a faint glow at least.....

[@CrimsonRepair]

It definitely is. Those switches are designed so when it's "on" the LED side of the switch should be in the flipped position. He's got it upside down and the wiring reversed.

[@jjrony7]

you are right it is backward

[@Dennis-mq6or]

I believe the brass connection is where the ground wire attaches to light the led when the switch is closed. If the led stays lit all the time, reverse the leads to the two remaining connections of the switch...

[@carbonrrpilot]

@@CrimsonRepair ive bought several batches of those switches, some close the circuit when led side is down and others are closed when the led side us up but they all look the same..... theyre from china, so nothing is for sure or consistent!

[@Dennis-mq6or]

Huge improvement Dave. It may only perform the same functions as it did before, but you made it much safer for the everyday guy to use, especially the circuit breaker / switch for those who do not have a circuit breaker switch built into the battery.. It would be nice to see a 2S bms on those meter batteries along with a resistor and diode to recharge the batteries while using the meter. The diode to provide charging isolation and the resistor to limit the charging current to 0.1 amp or less... The 4-wire connection is by far the best way to go because the voltmeter will accurately read the battery voltage over a very wide range of wire lengths and gauge variations between the voltmeter and the battery....

[@patrickdavey9692]

Your little swirch may have a led which needs the correct polarity

[@patrickaschoff9240]

For sure David you are switching the negative, technically not necessary to switch the negative in this type of circuit. The rocker switch light LED is a diode which requires correct polarity. So do us all the happy dance and rewire, switching the positive and ground the gold tab.

[@MrSpencerpaul88]

I commented on this without seeing your responce... I'm like 80% sure that's the case. But I really need to know haha

[@kurtrakeman9319]

Well done mate. Useful gadget for battery guys like us.

[@patrickaschoff9240]

David, the scope - connect back the harbor fright inverter and load the inverter with your 1.0 pf loads (resistive). Overloads are the cool things to see, try adding led lights or power supply type loads, these should cause the pf to challenge and sometimes really break up these less expensive inverters. And you may see the Puresine inverters break down at the peaks, not necessary bad but yeah interesting, for bad data monitor the Current now that's cool. You can't zoom in on the sinewave with amplitude just in time. Zoom out and in on time, zooming out you can see the sinewave shift when you add or disconnect the load. If you can record and take a snapshot of that event you could zoom in the see what the load step did to the sinewave. The crappy sinewave cause heating and performance on devices connected, that's is why you would want the a reliable inverter with 5% thd spec's. Getting this scope to take a snapshot should be easy but maybe not so much in real time for you videos. Most new scopes with IR or Bluetooth software it's not user friendly until you pay $$$$ for it.

[@yankey4]

Love it. V1 was fine but over kill is cool too. Thanks for sharing and God Bless.

[@stevec5000]

David you should get a label maker for your projects. I picked up a nice Brother P-Touch model at Goodwill for $4.00 that already had a roll of tape in it and just needed batteries!

[@eksine]

I think putting it in a box might be a problem because the shunt gets hot, if it is a problem I'd stick a fan in the box, actually tbh having the box seems unnecessary but this video is very helpful with the rest of the setup

[@raybacchus1026]

Good job David I like part 2

[@ETraylor3]

How will those batteries that run your meter charge? Just swap the polarity on the LED and it will work.

[@dash8brj]

Chuck in a 2S bms for LiIon and a DC barrel jack. Feed it 9V and let the BMS HV cutoff handle full charge disconnect.

[@melroyel2235]

Awesome upgrade! Dude you should do voiceover you have the voice for it.

[@ayubshaikh9156]

Baby´s advice / recommendations very important ,……! Very Cute….. Hydraulic. Terminal punch ,……. Celestial gift for a hands -on electrician….!

[@jwrhynejr9608]

Another awesome build upgrade! Thank you for your tenacity!!!

[@pigeon3036]

Awesome! Keep up the great work!😉😉

[@jamest5149]

You could have cut a slot in the ID of the gland so it fits over the terminal. Oh well, all sorted.

[@krakenking1597]

Super awesome! I like v2.

[@henvan8737]

The crimp lugs for the circuit breaker have too large a bolt hole. Smaller lug hole sizes are recommended as increases your contact area.

[@a2cryss]

Could you have used 3 cells to allow it to stay above 8v as they discharge? Would also allow the led to get proper voltage once the polarity is correct.

[@juliosolis8755]

Great work!!! This version seems to be awesome.

[@jmac430]

I'm not positive, but I think you may have installed that switch using the opposite polarity... (see what I did there? 😆 lol). It's an led so it does matter and I own the same ones, they work down to about 6v, to my surprise... Not a huge deal, just figured I'd pass that info along since it is a pretty nice feature having that on/off led feedback... Cheers! - Jesse

[@DavidPozEnergy]

Thanks for letting me know. And, yes, I got that. LOL

[@alanlester397]

you should have put double pole double throw switch. You could power the meter from the source or the 18650. You may be caught out with no 18650 power at some point.

[@benkanobe7500]

I did not see the plastic strain reliefs link used in this build as compared to the original with metal

[@ooglek]

Nice improvements! V3: keep your 2 x 18650 batteries charged when voltage is present. I don't think the power drawn will affect your experimental output, but if you're concerned about a 30mV loss, then maybe not.

[@trif55]

yea someone else mentioned using a little 2x 18650 BMS to keep them charged and balanced, the other thing would be to add a "charging" switch so you could disable/enable charging when you need to

[@MrElf31]

The switch light does not have a negative wire so no light is correct. It may still work with 8 volts. LED's use very little voltage. But its not needed in reality. I would love a parts list to build that in my own carlon box.

[@tommycurren8064]

U wired the switch wrong the darker terminal is for the ground and the other 2 terminals are for the positive i have a bunch of those switchs and they will light up with 5 to 16.5 volts other than that u did great i love watching your videos

[@u123446]

Dave, you did a mistake on the switch with the light that's why the light did not go on. here how to connect it, It's an easy fix: Connect the positive wire from the small batteries to the gold pin (you have that wrong), Connect the meter vcc to the middle pin. Connect the ground of the batteries to the last pin. that should turn on the light when the switch in the on position.

[@jamest5149]

Put a charging port for your modem back up batteries in the side

[@stevebabiak6997]

And put a real fuse holder on the outside so that it can be replaced without disassembling the box. Either a fuse is needed and thus will be expected to need to be replaced, or it isn’t needed at all.

[@eDoc2020]

@@stevebabiak6997 Uh, the fuse is a safety device that's there just in case. It's not expected to blow but is still "needed" because something might fail unexpectedly and cause excessive current. Personally I'd also put a fuse on the + sense wire from the battery because this wire would also carry excessive current if the meter shorts out.

[@mdesm2005]

your sense wire doesn't carry any current, so it could be smaller than 16 gauge

[@CollinBaillie]

Did you ever fix the reversed wires on the switch? Typically you switch positive. So the LED is effectively wired backwards, and will not light.

[@sadfur8728]

Are the schematics for the energy meter available anywhere? I connected mine with the shunt ground connected through a BMS and the voltage ground directly to the battery negative. It didn't like it when the BMS cut power and the common mode voltage came up off ground, and burned out somewhere. Curious to see what happened, so schematics would help find out..

[@Dutch_off_grid_homesteading]

heya 1 more nice meter for your collection keep the vlog's coming love it

[@slidewaze]

That roll of #4 wire looks expensive. (Enjoying your vids!)

[@korishan]

Generally those thin nuts are referred to as Jam Nuts. They are used quite often in automotive on the tie rods, or any rods that can be adjusted in length for calibration. Other applications are where you need a narrow nut for low profile. And for locking another nut in place as well, using 2 nut against each other. As I type this, it get's more and more naughty sounding the more I type 🤣

[@DavidPozEnergy]

Thank you for your comment. I didn't know the official term for the thin nuts. Jam Nuts. Thanks.

[@cpirius]

Nice, great updates :)

[@roberte.3541]

is there a reason not to solder the lugs onto large electrical cable for instance 4/0 it seems most people crimp them

[@DavidPozEnergy]

You can solder them if you prefer. It's just hard to get enough heat for a good solder joint with 4/0. I've tried it with a torch, but I made a mess melting the insulation. LOL I've gotten very good, consistent results with a crimper, and it's fast.

[@therichofficial1465]

I like this video. BTW, can this PZEM-015 mesaure a parameter charge of battery?. Such as time charging and amperage charging.

[@Maxttor]

and lithium cells it´s gonna work? thanks for sharing knowledge

[@f.k.6151]

Hi. Thanks for the video. What is the name of the meter you have mounted on?

[@brianposton8547]

What is the part name and number for the shunt and meter you used? I have a 200 amp battery and want to build this type if box. Love all the information you pass on to average guys.

[@mikejf4377]

I like this one. Great video.

[@Imagi10]

Thanks, if i connect without shunt (in Pzem 013 version) it is safe sir?

[@rickharms1]

This unit measures volts and amps, but not Ah (amp hours) To me, Ah is "capacity". Now, I will concede that I could very well be full of "you know what", especially because you have much, much more experience than I. I made this comment only to be corrected, if necessary, by those with more experience. Thank you for your videos.

[@jec_ecart]

Is this a bidirectional meter? Does it work for charge discharge?

[@jwrhynejr9608]

ABSOLUTELY GREAT INFORMATION

[@gkeith4120]

Me. David, why did you bring both the negative 16awg from the battery side of your input cable instead of from the other end of that cable? Thanks

[@gkeith4120]

Good job BUT I certainly would’ve appreciated if you would’ve given us a link or at least a description of what the plastic locknuts for the wires were. Could’ve save me a half hour of looking for the damn things. PVC Threaded Strain Relief Connectors

[@OrbOPic]

Hi Dave, could you redo this all again as this didnt show the internal resistance of the battery if you didnt notice another major thing that shows health of battery.

[@benkanobe7500]

If you get a chance, could you add the links for the materials used in this Version Two, please?

[@DavidPozEnergy]

Sorry, I don't have links for everything because sometimes I just use what is kickin' around.

[@f.k.6151]

Can a BMS be installed on a battery that has a built-in BMS? How about a BMS for a sealed gel battery? Thanks

[@DavidPozEnergy]

A lithium battery only needs one BMS, not sure what application would warrant a second.

[@MrSpencerpaul88]

I'm super curious about the 12v switch you fitted, is it upside down? As it could explain no light at all, and I'm thinking the little light should be on the "on" side not the off side. Please please please test and let me know it's driving me crazy not knowing haha

[@benedictcalantoc7115]

Can you use this for 48v battery too?

[@robertojustonal9617]

Do you have a diagram for that circuit?

[@undefinednull5749]

is the meter broken? Why doesn't it show internal resistance ? ?

[@sailon4me]

Will this battery meter work on an FPV battery?

[@peterlindstrom8865]

Do you have a link for the plastic Cable Glands? The link you provided is for the metallic ones. Thank you for the video. Great inspiration to me regarding the meter box!

[@DavidPozEnergy]

No, sorry. You might have better luck at a local electrical supply house.

[@ricardobernardo2603]

Thanks for sharing ..

[@roadsidediagnostics1017]

Most automotive batteries wouldn’t spec Watts/Hour. Is there any mathematical way to see the relationship between Amp/Hours. Take an AGM 096 battery listed as 70Ah and 720 cold cranking amps (CCA). Sorry if daft question but only ever used a standard hand held battery tester. Was interested in your Wh tests. Thanks

[@DavidPozEnergy]

If your example AGM battery is 70ah and 12v, then multiply the two for wh. 840wh. I like to talk about wh or kwh because I've seen confusion before between testing 12v batteries, 24v batteries, and 48v batteries. Heck, I've even tested 36v batteries.

[@josepeixoto3384]

For solar setup that meter is almost worthless,because it ADDS up the Ah going in and the Ah going out ofthe battery; AND ,at the end of the day,or night... you still don't know how many AH went in or out, just a messy salad of both. Been trying to make it register ONE WAY only,maybe with a diode(??) but i don't think it can be easily done, now.

[@rolliebca]

Hi David, loved this video, BUT there's a Kickstarter campaign ending in 2 days you need to be aware of. It's a redesign of the ElectroDacus SBMS redesigned for mass production. It can be found here: @t He's close to his target but could definitely do with a push! Thanks, and I look forward to your next video.

[@G36934]

awesome job!

[@VTX1029]

You have the polarity wrong on that switch. Negative to the brass post, positive to the silver posts

[@emilee172]

my lighted 12 volt power switches light up on 8 volts, it gets dim as the voltage drops but still work, did you hook up the switch correctly??

[@stanjarmolowicz]

there is no link for that cute small crimping tool and connectors ..please supply i'll die if i don't get that one

[@DavidPozEnergy]

LOL

[@stanjarmolowicz]

@@DavidPozEnergy i'm on my last breath .... link please !

[@DavidPozEnergy]

www.aliexpress.com/item/33038304527.html

[@LukeRT]

The 100amp breaker can it be a house AC breaker or does it have to be a special DC breaker, basically is there a difference when it comes to the actual breaker

[@DavidPozEnergy]

There is a difference. DC (battery) can span a long distance. AC (house) can't. So breakers made for AC have a tiny gap. Breakers made for DC have a large gap inside. I linked to the breaker I used, it's less than $30 and won't burn up like a house breaker would. Now, there are always exceptions. Sometimes a breaker is rated for both AC and DC, but it needs to be specified and written on the breaker.

[@LukeRT]

@@DavidPozEnergy Thanks for the help, makes sense but good to know. Had a stack of AC breakers but good to know not to use for DC

[@stevebabiak6997]

@@DavidPozEnergy - some breakers don’t like to be treated as a switch, due to arcing at the contacts when the load is connected and disconnected. You want to be sure that your selected breaker is rated for use as a switch, otherwise the contact deterioration from the arcing will render your breaker to be like an intermittent connection.

[@eDoc2020]

A rule of thumb I've heard is that you can use an AC switch as a DC switch, but at 1/10 the voltage. So for example if you have a 120vac switch it could work for 12vdc. If this rule is true (and I'm not sure it is) then it probably would also apply to breakers.

[@mawonaful]

You know the meter used there. Can it measure both ways? I mean incoming and outgoing currents? Please someone answer this. Im just about to order it now. Sorry for my english hope it is understood the question.

[@mrtechie6810]

It is not a coulomb meter. It accumulates regardless of the direction.

[@hoosiersolarpower974]

hi David really enjoy your how to videos can you or have you used a honda/toyota hybrid batteries NIMH 48 volt system if so which BMS would had used

[@teadott]

You should have drill a microscopic hole at the top under the bottom right corner left adjacent side. Give the man a break LOL.

[@chrislewis9345]

Just curious on your thoughts....do you think 8ga wire from the batt to the inverter is adequate for about a 10ft run when powering an inverter at normally under 500watts but occasionally running coffee maker or microwave at 1500watts or so?

[@DavidPozEnergy]

There are a lot of variables. Here is a reference: www.altestore.com/howto/recommended-inverter-cables-sizing-and-breakers-or-fuses-a62/

[@chrislewis9345]

Would I be correct in assuming that the output of any inverter would be near equal to its input draw on a 12v battery?like 1500 watts out would be 1500 watt draw on batts...just do the math and change it to amps.correct sorta?lol

[@DazzaDirect]

@DavidPoz #DavidPoz and/or anyone who knows is this meter used in both videos bi-directional measuring amps and if so does it have a minus sign that appears and does the accumulated Ah change, thanks for the great content ;-)

[@mrtechie6810]

No, it is not a coulomb meter. It adds regardless of charge or discharge.

[@ianjordanchutherpal9294]

Do the 18650 cells get charged through the meter or do they need to be removed to charge?

[@DavidPozEnergy]

I'll unscrew the lid and remove the cells to charge them in an external charger. The meter doesn't draw much power, so I might have to do this in a year or two.

[@wdbyrd2]

@davidpoz I'm going to build a battery with the same cells you used possibly even the 6AH cell and will be sure to use your promocode. I was just curious if it is ok to have a constant 40 to 50 Amps discharge when the cells are rated for 3C (15A) continuous and pulse discharge of 10C (50A) is that safe and what will that do for the life of the battery cells? I want to run a HF Radio with 21A discharge while transmitting and 1A while listening for an average of 5.5A over an hour. Would this be safe and will my batteries last me a good deal of time doing this. Thanks for the great content.

[@justinanderson9747]

Look at the description on batteryhookup. Their 5ah cells are rated for like 5.5 or 5.6ah but they label them as 5ah. The 6ah are actually 6ah so the better deal is the 5’s for the money

[@jws3925]

Why did you not just use a 9v battery?

[@jws3925]

Hey David. I made a box just like your version 2. I have a question about the independent power supply. First, did you disconnect the power feed (ground and power) from the main battery and using the independent power supply exclusively? What happens if you have both hooked up to the monitor? I seems like there would be a bit of a "conflict" of two different voltages being fed to the monitor. I am really confused on the issue of the independent power supply. I understand the "why" you do it, I just don't understand how to use it correctly. Do you only use it when the main battery voltage drops below 8v or do you use it all the time? If all the time, in conjunction with the main battery power feed or??? I just watched the video again and I noticed your wiring of the monitor. First of all you didn't use the ports for the external power supply at all. It appeared you took the external power supply wires and connected them where the battery + and - leads would have gone. You really didn't show you hooking up the wiring. The video cuts from putting the ferrules on the external power leads to the whole thing being wired up and there wasn't a good enough shot of where all the wires went really assess how you wired the things up in terms of the power supply to the monitor. It looks like the two areas on the monitor where the external power supply wires would go is empty. Can you clarify all of this? Obviously by my first comment I wired my monitor up so the monitor essentially has two power supplies (ie, the first question above). I am not really comfortable having both power feeds going to the monitor. I do have the external power supply switched so I figured I would just keep it off unless the BMS shuts everything down and then I would switch on the 9v external power source. What do you think?

[@DavidPozEnergy]

If the battery you are testing is over 8V, then you don't need an external power supply. For me, I test a lot of batteries (12-48v) with BMS's built in (battery management system). The BMS can shut down the battery, and then I'd have no voltage to the meter. If I'm filming that then I'd have to add voltage in order to make the meter turn on, so that I can read the numbers. Now, the meter stays ON so I can check the numbers easier. Sorry for the confusion, I followed the wiring diagram printed on the back of the meter.

[@jws3925]

@@DavidPozEnergy Thank you for your reply David. Enjoy you videos and various projects.

[@DIYwithBatteries]

Loved it.

[@chrislewis9345]

Any thoughts on Makes sky blue products? Namely mppt 60a charge controller?

[@DavidPozEnergy]

I've never tested them, so I can't say anything good or bad. There are a lot of them out there, so probably OK. I once looked at buying one when I had Chevy Volt batteries, but the voltage range was too narrow.

[@darrenorange2982]

Hey David, I'm working on finishing up my power wall and I'm trying to get a good BMS for my Bolt EV batteries that are 48V 14S. What would be a good BMS that would be reliable to protect the batteries and balance them? Thanks!

[@DavidPozEnergy]

If you need a 100 amp BMS, then Battery Hookup has a good one. I've tested it and works well and balances really fast for a little BMS. batteryhookup.com/collections/accessories/products/12v-lifepo4-smart-bms-w-low-temp-cutoff You can use my code "DAVIDPOZ" for 10% off. Make sure you select the right one from the drop-down list. But, if you need more, like 200 amp, then try a Daly brand. I have several Daly brand BMSs on my builds and they work well. They do have balance, but it's not very strong.

[@darrenorange2982]

@@DavidPozEnergy Thank you! They are currently sold out for the 14S I would need, do you think they will get more?

[@darrenorange2982]

@@DavidPozEnergy I also don't know that I need 100amp but atleast 60-80amp

[@EpalzeoG]

Thanks for the nice video. Does it tell you if the battery is in Charge mode or Discharge Mode ? I tried on my side and I am disappointed. My current is always positive wether I am discharging or charging the battery.... Maybe I did something wrong... But hard to know... Thanks in advance if you can confirm or not on your side.

[@DavidPozEnergy]

I've only used it discharging, IDK