inline watt meter for 72v battery?

jimmyhackers

10 kW
Joined
May 11, 2015
Messages
600
all the watt meters on ebay that are inline seem to only go upto 60v.

bit anoyng as my bike battery is 72v.

does anyone know if there is one that goes upto around 100v ?

or wether those ones on ebay can go higher than 60v?
 
Solar seems to be your forte

80v https://www.banggood.com/DC-500V-50A-100A-200A-300A-500A-Wireless-Voltage-Meter-Ammeter-Solar-Battery-Charging-Coulometer-Capacity-Power-Detector-Tester-p-1721288.html?cur_warehouse=CN&ID=515283&rmmds=buy

100v but only 10a https://www.banggood.com/Digital-DC-0-100V-0-10A-250W-Tester-DC7-12V-LCD-Digital-Display-Voltage-Current-Power-Meter-Voltmeter-Ammeter-Amp-Detector-p-1466966.html?rmmds=detail-left-hotproducts&cur_warehouse=CN&trace_id=60271644987229653

AC meter might work with dc???? https://www.banggood.com/KWS-AC301-8-in1-Voltmeter-Ammeter-AC-50-300V-Power-Energy-Meter-LED-Digital-AC-Wattmeter-Electricity-Meter-0-100A-p-1902439.html?rmmds=detail-topright-recommendation&cur_warehouse=CN&ID=6314200&trace_id=60271644987229653

200v 100a dc https://www.banggood.com/KWS-DC200-0-200V-0-100A-DC-Digital-Display-Voltage-and-Current-Meter-Color-Screen-Power-Tempterature-Tester-Timer-p-1767174.html?rmmds=detail-topright-recommendation&cur_warehouse=CN&ID=517856&trace_id=60271644987229653

90v 100a dc https://www.amazon.com/Charge-Discharge-DROK-Watt-Hour-Multimeter-Shielding/dp/B08JB5NQ4B?ref_=ast_sto_dp&th=1&psc=1
 
ive seen ones like those before.

annoyingly nearly tripple the price..

the inductive ones would require me to desolder either a pos or neg lead from my battery/battery loom to loop it through the tester module. which isnt ideal

i really wanted a more plug and play inline temporary thing.

ive ordered a cheapy 100a 60v thing.... i will take apart and have a butchers. maybe suck it and see, just plug it in.
for a tenner im not to fussed if it pops.
 
My batteries all use XT60 connectors on the power leads. I have a Drok power meter with XT60 Male/fFemale connectors I can pug in-line between the battery and the motor ... or between the charger and the battery. But I got by with a DC 6.5-100 Volt 20 Amp meter that did not require an external shunt.

https://www.amazon.com/dp/B07FYHTBD2

I think nearly over 20 amps needs an external shunt

https://www.amazon.com/dp/B07QVXXGVR
 
Quick and dirty solution, 72v=20s. open battery connect a small wire at 10s (36v) to the + of the cheap 60v max. wattmeter. AH reading stays accurate. Double volt, watt or WH readings. If connect at 2s them V,W,Wh needs 10x which is easier math but less resolution. Most of those wattmeters need more than 2s to display, but have a separate power connector (9v+) so they can be used for low voltage applications.

You'll only be monitoring part of the battery's voltage but the BMS should keep the cell V's matched.
 
i know all too well abou the amp limits of those internal shunts,

ive run one so hot it desoldered itself from the board. :)

i did think about one per 6s battery i have (3 in total).....but id really like something that i can use on other things. (my friends bike batteries)

they all have 20s with a bms boards on 3000w bikes so no real chance of splitting the pack like mine will.

i will have a look at a drok power meter
 
Here is one I have ordered. DC 0-300V 300amp. Apparently the shunt is removable.

https://www.aliexpress.com/item/1005002752302199.html?spm=a2g0o.order_list.0.0.21ef1802ZMrVFr
 
Audisport09 said:
Here is one I have ordered. DC 0-300V 300amp. Apparently the shunt is removable.

https://www.aliexpress.com/item/1005002752302199.html?spm=a2g0o.order_list.0.0.21ef1802ZMrVFr
That looks like it may be bidirectional as well.
 
LewTwo said:
Audisport09 said:
Here is one I have ordered. DC 0-300V 300amp. Apparently the shunt is removable.

https://www.aliexpress.com/item/1005002752302199.html?spm=a2g0o.order_list.0.0.21ef1802ZMrVFr
That looks like it may be bidirectional as well.

I'm not about, I will post pics when it gets here. Looks promising.
 
ive seen/used those before. they are great for a permanent installation.

i would prefer plug and play inline for temporary testing.

i figure a lot of the problem is finding a voltage regular with a high enough input voltage range. as even that unit requires a seperate 5-12v supply im guessing for the lcd and leds maybe some of its microprocessory things.
 
jimmyhackers said:
ive seen/used those before. they are great for a permanent installation.

i would prefer plug and play inline for temporary testing.

i figure a lot of the problem is finding a voltage regular with a high enough input voltage range. as even that unit requires a seperate 5-12v supply im guessing for the lcd and leds maybe some of its microprocessory things.

You could easily mod that with two connectors either end for easy in line connection.
 
I use this for up to 500v DC and 300A.

Its got wifi and was 20$. Hall sensor shunt, bidirectional.

VAC8010F-500V

https://www.google.com/search?q=VAC8010F-500V&client=firefox-b-1-d&sxsrf=APq-WBsJIJCKBQem3_Y-vae3GMS1YfcZiQ:1645805119393&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjH9IrsnZv2AhVFjIkEHfeEBmoQ_AUoAnoECAEQBA&biw=1920&bih=937&dpr=1
 
well i got the inline meter today.....

didnt blow up....but sure as hell works funny on a 72v battery (it doesnt). didnt read the voltage correctly as well as everything else (watts amps etc).

taking it apart ......the shunt appear to be several surface mount shunt resistors just stacked up in a mess (see picture for a laugh).

works ok on my 48v battery/bike though so not a total loss.

yes that unit could work and is probably my best option (thanks for showing it to me)......but it will require a seperate battery solution as the way its powered is 5v-12v.

not a big hassle....9v battery should be fine.

will get one on order
 

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jimmyhackers said:
well i got the inline meter today.....

didnt blow up....but sure as hell works funny on a 72v battery (it doesnt). didnt read the voltage correctly as well as everything else (watts amps etc).

taking it apart ......the shunt appear to be several surface mount shunt resistors just stacked up in a mess (see picture for a laugh).

works ok on my 48v battery/bike though so not a total loss.

yes that unit could work and is probably my best option (thanks for showing it to me)......but it will require a seperate battery solution as the way its powered is 5v-12v.

not a big hassle....9v battery should be fine.

will get one on order

Mine finally arrived. :D Managed to make it plug and play in line with two xt90. 0-300v no extra 5-12v needed. 300amp amps current. Working great for charging lipo. Love the clarity of the display
IMG_3282.jpg
 
looking neat and compact, i like.

mine came but its still in the box :lol:
ironically im waiting for another box to put it in.

howd you get it to power up without a seperate power supply?

have you used it on your ebike yet?
 
jimmyhackers said:
looking neat and compact, i like.

mine came but its still in the box :lol:
ironically im waiting for another box to put it in.

howd you get it to power up without a seperate power supply?

have you used it on your ebike yet?

I just wired the test range input in to the source side. As long as you are testing more than 8 volts it should work.

The other unit I bought for my ebike has stayed in the box too. I thought I could make it water resistant but it looks like its going to be quite a challenge. I think it would require some sort of custom enclosed. So many ways for water to get in. What box are you waiting on? Is water resistant by any chance?
 
i gave up on china box, they told me they didnt have/ship it and i would get a refund.

ive ended up using an old driver bit box, i had a few laying round. finally pulled my finger out today.

heres a few pics, thing works great, is a 2-3 second refresh/update rate which isnt ideal.

but at least now i can get some wattage numbers.
 

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