Battery indicator on display vs batteries display

neutron

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The battery indicator on my display has 5 bars and the lights on the battery itself only have 4 lights to indicate remaining charge level. I've noticed the display will get down to one bar indicating 1/5th charge remaining while the battery still shows 2 lights which would indicate 1/2 charge remaining. Which is more accurate?
 
I will unhelpfully tell you "neither". Graphical displays like these are notoriously inaccurate, and each one of them has its own, unique methodology. Additionally, neither device is likely manufactured to high standards of accuracy. They literally could both be wrong. And even if one or both of them is spot-on accurate... what do 3 out of 5 bars really mean? Just yesterday I installed a new display on one of my bikes, and the manual shows what the five bars means, and gives some rather opaque discussion of what the actual voltages are depending on the battery voltage being used.

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None of the above is worth anything when looking at a different light or display, regardless of whether or not it has the same 5 increments.

Luckily for me I have a separate display that shows actual battery voltage. as in "53.5v" and the like. It is a KT display and over time I have found that brand of display is actually quite accurate - based on testing with a quality voltmeter.

For me, it is a dealbreaker to not have a display that shows actual voltage. Further, I have learned what the various voltage values actually mean, and my chargers have a voltage display on them as well. If you want to have a decent answer to this question, you will need to go a lot deeper into this topic. Maybe buy yourself a wattmeter, use a quality meter to determine its accuracy and then plug it inline into your bike's power connection.

If not, if you don't want to know that badly, you're just going to have to pick what was once called the 'idiot light' that you decide to trust and move on.
 
Okay thanks for the info. I had a feeling I couldn't trust either to be accurate. I don't really need to know precisely how much charge is left, just a general idea. So far I haven't strayed too far from home and have been charging the battery when I get the trip odometer up to 50 miles. I'm pretty sure I can get at least 60 miles on a charge doing the type of riding I do. I use pedal assist 2 99% of the time and only use the throttle to get started or for maneuvering in tight spaces where a sudden boost from the pedal assist would be unwelcome.
 
the only real way to know which meter is showing the closest to accurate estimation would be to check you battery voltage with a volt meter and then look at a state of charge chart to see what the real % of charge is.
 
My 48v battery measures 47.5v after 40 miles and starting with a full charge. According to the chart I should have 53% left on the battery. Is this correct? The indicator lights on the battery show 2 out of 4 lit. The display shows 2 out of 5 lit. I doubt if I could get another 40 miles. I'm sure I could get another 10 given similar riding conditions. The battery seems to be like the fuel gauge in my car; it goes a long way before the needle moves off of full. Then it moves faster on it's way to empty.
 
47.5v on a 48v battery would be 53% on the state of charge chart i have. but i have also noticed with my batteys and bike that the first half of the charge gives me a lot more range,speed and power than the 2nd half does. esp when it gets down to about 43v with my new controller which is around 25% i have almost no power to get any speed and if i hit any sort of hill its tries to draw too many amps and shuts down my bike. MY old controller and display which was just a very basic one with leds for the power meter would be all the way down on just 1 blinking led at 43volts and still would not really slow down to much or shut off on its own till it got down to 40volts. which is still almost 10% but way not good for a battery to be run down that low.
 
I rode 40 miles and checked the voltage. 48.5 which indicates that I still have 61% battery left. So I rode another 10 miles and the voltage was 47.3 which indicates I have 53% left. I guess I'll push it another 10 miles to see what happens with the voltage. I don't want to get below 20% on the battery but I'd like to know how far I can go before hitting the 20% level. I'm riding a KBO Breeze with 500W motor and 16 ah battery. I'm using PAS 2 over 95% of the time on mostly level trails. I'll use the throttle to get going from a stop and occasionally when passing someone to get around in a hurry. I'm really happy with 50 miles on a charge and still having 53% left. I realise I won't get another 50 but I think I can get another10. We shall see.
 
Just did a quick 5.5 miles this evening. The voltage is down to 46.8 so 50%. I'll try and get a other 5 miles in tomorrow and check the voltage again. Display shows one bar out of 5, battery shows 2 lights out of 4.
Another 5 miles and the voltage is 46.4 so about 47% left. 60.4 miles on this charge. I'm guessing my odometer is off by about 5% according to the mile markers on the trail so probably closer to 57 miles.

Edit: I'm up to a little over 70 miles with 42% battery left. That's good enough for me. I'm not going to push it any further because I can only go five miles at a time to keep from suddenly running out of juice. Time to recharge.
 
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