A more accurate battery meter

[Altema]

The original Rad battery display had 5 'bars' or segments in the battery icon, and it was pretty accurate. The KT-LC3 display that I'm using now only has 4 bars, and leaves me guessing more than I like. When I converted to 52 volts, the battery icon became useless despite the battery monitoring mode selected. So I shopped around, and found an independent display that is programmable and removes the guesswork. The battery icon has 7 segments, and the unit displays this, plus the battery voltage and exact percent, all at the same time. And if you do drain your battery all the way, a red lightning bolt flashes on the screen, and you can program it to actually sound an alert at a voltage you choose. This would come in handy of you are cruising along and enjoying the view, and would give you an audible beep at 20% as a reminder.

The most difficult part of installation was mounting, and I settled on an unused handlebar clamp I had cut off another device. The only open spaces on my handlebars were curved, so I chose the left side, affixed an angled plastic support to level the display, then affixed the display to the new mounting pad. I normally don't use hot melt glue in cases like this, but I needed something that would also act as a filler, and I used the higher temperature version. I had difficulty finding suitable wire (didn't want speaker wire or lamp cord), so I used a thin headphone extension cable and cut off the ends. The cable was routed along with the other wires from the handlebars, through the frame loops, and down under the crank, then it was run back up to the main Anderson connector for the rear battery. I disassembled the Anderson connectors and soldered the wires to the terminals, and the wires are so thin that they act as a fusible link in the event of a short.

Connected at this point on my particular bike, the battery meter will display the voltage of whatever battery or batteries happen to be live at the moment. As a bonus, I can check individual battery voltages by turning on one battery at a time. This is a big deal for me, as it means I don't need a voltmeter anymore. The meter is programmable, and I have mine set to L-14 for Lithium Ion battery, 14 cells. The cell are referred to as "strings" in the instructions, and it can be a bit confusing the way it is worded. The simple way to determine the correct number is to take the voltage of your battery pack, for example 52 volts in my case, and divide it by 3.7 which is the nominal voltage for an individual lithium ion cell. 52/3.7=14.05, so I rounded off to the nearest whole number and set mine to 14. The normal Rad battery pack is 48 volts, working out to 48/3.7=12.97, so you would use 13 as your setting.

A link to the meter is below, and even if you choose a different meter, some of these installation tips may be helpful.
https://amzn.to/3cRArN4

[Veggyhed]

Nice write up. Thank you.
Do you think in a single battery configuration that you could just run the meter via the barrel connector and the charge port to the battery?

Sent from my Pixel 3a using Tapatalk

[Altema]

Nice write up. Thank you.
Do you think in a single battery configuration that you could just run the meter via the barrel connector and the charge port to the battery?

Sent from my Pixel 3a using Tapatalk

Splicing the meter in at the front of the bike would be easier and neater, but I wasn't sure of the pinouts. It would work just as well as my current connection for single or multiple batteries, so I may switch once I find out the correct wires to use.