Battery monitor, speedometer, odometer and tripmeter

Projects General Guidance
1

Hello!
I would like to know if Arduino is the right way to go for my project
I have a electric trike that has no battery monitor, now I use the tripmeter of bicyclecomputer, I know with a full charge of the batteries I can go about 100km.
But I feel that there should be some better way of measuring the level of the battery
I have 16 of these batteries in series connection

What do I need to make it possible? if it is possible
Anybody know of an already finished product that would work for me?
The speedometer, odometer and tripmeter are mostly just big + but would be really good to have everything in one device

2

A few of these....

https://www.gmelectronic.com/ev-peak-voltmeter-lipo-alarm

bmeter.jpg

bmeter.jpg

3

pazante:
But I feel that there should be some better way of measuring the level of the battery

That's not so easy because the voltage will vary depending on the amount of current being drawn from the battery. Imagine, for example that you measure the voltage when no current is being drawn and then switch on the motor to climb a hill. As soon as the motor draws a large current the voltage will fall even though almost no electricity has been withdrawn from the battery.

If you can measure the simultaneous current and voltage at frequent intervals (perhaps a few times per second) and accumulate the data you would know how many watt-hours had been consumed and you would have a rough estimate of how many watt-hours remain in the battery - assuming you knew the full-charge capacity and assuming it was fully charged when you started the measurements.

But a further complication is that the total capacity of the battery will decline with age so it may not even be easy to know the full charge capacity.

...R

4

Am I super wrong thinking that something like this would work

I am a total noob so I'm just googling around trying to find something

5

You might need to make a voltage/charge decay curve for your battery setup, then you might be able to estimate the remaining run time of the batteries. Set the trike up on blocks, add some load to the tire, then record and graph the voltage over time until until the batteries are depleted. Then you could just have a volt meter on the bike while riding to get an idea of the remaining run time on the batteries.

6

zoomkat:
until until the batteries are depleted.

Depleting the batteries may not be good for them.

...R

7

Robin2:
Depleting the batteries may not be good for them.

I have an BMS that I hope takes care of not depleting and overcharging the batteries
I'm curious is my setup harder to measure then other lithium batteries
Because most of the e-bikes I have seen have some sort of battery level measurement

8

pazante:
I'm curious is my setup harder to measure then other lithium batteries

I don't know anything about your setup so cannot comment.

Because most of the e-bikes I have seen have some sort of battery level measurement

I don't know how they do it, and I guess you don't either.

...R

9

"I'm curious is my setup harder to measure then other lithium batteries"

Probably not. You can start by connecting a multimeter across the battery terminals and monitor the battery voltage as you ride the bike around.