2 wire high voltage battery voltmeters and more

Hey guys, so I've been on the lookout for a simple voltmeter to install on my home built battery packs (at least supporting 20s ideally 24s). I didn't want one that required a separate low voltage power source, which was all I was finding (ones requiring <30v power supply). Well, I finally found one, and decided to comb through "all" of aliexpress for others. I figured I would share my findings, and hopefully other people can post ones they found. Ideally, people can then review ones they have purchased and share their results here. I did my best to not pick duplicates... picking the cheapest of the identical (but there's a bunch of the real simple noes ranging in price that are hard to tell apart).

Please only post meters that do NOT require a separate lower voltage to power, and meters that support >36v, ideally closer to 100v+. Lower voltage meters, and ones require lower voltage power supplies are insanely easy to find, so pretty much no point in posting them.

**PLEASE NO AFFILIATE LINKS, UNLESS THEY INCLUDE A DISCOUNT AND ARE LABELED AS SUCH****... none of my links will be affiliate links

I'll start with the first one I found, which happens to be the cheapest. The title says 45-120V, but the description essentially says 4.5-84v (I trust this number more) and currently only $1.57 shipped:
https://www.aliexpress.com/store/product/0-36-DC4-5-120V-Car-LED-Display-Digital-Voltmeter-Volt-Meter-Automobile-Motorcycle-Voltage-Gauge/833031_32761590308.html

The "Mac Daddy" of all the meters I found (at a good price, IMO), monitors Voltage, Amps, Temperature and Time, among other things, with user set Alerts...
0 - 300 V at 0.05 V resolution Voltmeter (when under 7.8V requires separate 4-30V supply, BUT for 7.8V-300V it runs off the testing voltage)
0 - 110 A at 0.05 A resolution Ammeter (with an internal shunt)
0 - 999.999 Ah Capacity range, with 0.01 Ah precision
0 - 99999.9 Wh Power Cumulative range, with 0.01 Wh precision
0 - 2999.99 W Power range, 0.01 W precision
1 - 999.9 Impedance range, 0.1 precision
0 - 99 ℃ Temperature range, 1℃ precision (With external temperature probe)
Measures at 2 Hz (every 0.5 sec), and you can set a ton of different alerts, and timers
And more... for $12.11 bare or 31.15 in a shell, shipped
https://www.aliexpress.com/item/AC-300V-100A-Accurate-Energy-Meter-Voltage-Current-Power-Voltmeter-Ammeter-Greem-Backlight-Overload-Alarm-Function/32819133911.html

The "Mac Daddy's little brother":
5-150 V, 20 A (under 5v requires separate Power Supply)
Plus external temperature probe that measures 0-80 ℃ with 1 ℃ precision
Only $5.61 shipped
https://www.aliexpress.com/store/product/DC-150V-20A-3KW-digital-voltmeter-ammeter-power-supply-voltage-meters-detector-wattmeter-volt-current-capacity/2022043_32834746174.html

Or without the temperature probe, $5.37 shipped
https://www.aliexpress.com/item/150V-20A-3KW-DC-digital-voltmeter-ammeter-power-supply-voltage-meters-detector-wattmeter-volt-current-capacity/32821454762.html

Or the BABY brother:
4.5 - 120 V, $1.87 shipped
https://www.aliexpress.com/store/product/Digital-Voltmeter-meter-voltimetro-Car-Electromobile-Motorcycle-battery-6V12V-24V-Voltage-power-supply-tester-electronic-doctor/2022043_32792861463.html


And here's a few more basic voltmeter "runner ups":

1-100 V, 0.56" display, $3.43 shipped:
https://www.aliexpress.com/item/Electric-Motorcycle-Voltage-Tester-DC-7-100V-Green-LED-Digital-Panel-Volt-meter/32661762464.html

20 - 80 V, $5.19 + $1.53 shipping (to US) = $6.72 shipped:
https://www.aliexpress.com/item/Car-digital-volt-voltage-panel-meter-voltmeter-digital-DC-20-80V-car-motorcycle-battery-monitors-with/32354569089.html

15 - 120 V, $8.50 shipped:
https://www.aliexpress.com/item/Digital-Voltmeter-Green-Led-Display-Voltage-Monitor-DC15-120V-Voltage-meter-DC-24V-36V-Volt-Meter/32622326242.html

4.5 - 150 V, 0.56" display, $6.64 shipped:
https://www.aliexpress.com/item/0-56-DC-DC4-5-150V-V27D-Two-line-Digital-Red-LED-Bassinet-Voltmeter-Battery-Car/32643854453.html


I plan too order at least the 3 hidance (the Mac Daddy, and 2 cheaper ones from same store), and maybe 1 other one in case the really cheap one is total garbage. Other than the "Mac Daddy" (which looks pretty damn good, with very accurate readings), there's really no way to tell the quality/accuracy of these without having one in your own hands.... I can't say I trust the specs on them... but definitely wouldn't want to exceed them.

Very nice stuff. Ordered BABY brother and Mac Daddy's little brother yesterday.
Usually these similiar 100V 10A models require external power and price is higher too ~9$
But if you still need separate external power, Im using these work great 40-320V DC input:
12V https://www.ebay.com/itm/191981585009 ~1$
5V https://www.ebay.com/itm/201542446064 ~1$
These are fully isolated too and few output volts hackable (changing TL431 resistor) :wink:

Also discovered this 120V 100A bi-directional couloumb meter Wireless ~23€ https://www.ebay.com/itm/112093372715
Similiar models go up to 300A 400VDC. Needs separate PSU though.

Yeah, that was my whole point in the post, all I found before today were 3+ wire models requiring a secondary power source. I actually already have a bunch of buck converters (and boosts for that matter), which was plan B if I never found these.... but def prefer these. I think I'll be installing the "little brother" in my current build... Voltage and temp is pretty much perfect for throw in a battery build as an additional sensor... and seriously, can't beat the price.