Ever wonder how depleated your battery really is?

Lost

Active Member
Just ordered one of these: (Link Removed - No Longer Exists)
I used to have one for my rc days, and a charger that would also tell me how much I put in. It's valuable information really, when I come back from my ride with a rover, and two bars are left, what does that really mean? By putting this inline with your charger (I am going to solder in appropriate male/female power connectors) and setting it up at the start of the charge cycle, it will tell you how much power went back into the battery.
Note: This is not a sure fire way to know how much your battery contains, just what it took to recharge it, and this a general guide line to whats going on. If I have an 11 amphour battery, and I am sticking 8 amp hours back in after a ride, I can at least set up a base line and compare it the "gauge" on the bike.
 

harryS

Well-Known Member
It's too bad that there's no way to add these between the motor and battery w/o cutting wires and voiding a warranty. With my kit bikes, no concerns,

I found wattmeters great for telling me how many watt-hours/mile my motor actually uses, and how higher speed and pedal assist change the equation. Still, once I know what my bike burns at 12mph, 14mph, etc, there's no need to keep measuring it.

I haven't tried to deplete a battery while measuring the watt-hours it delivered. I know the actual will be a lot less than the advertised which is based on a full discharge, but the low voltage protection circuits won't let us go near full discharge.
 

Lost

Active Member
I haven't tried to deplete a battery while measuring the watt-hours it delivered. I know the actual will be a lot less than the advertised which is based on a full discharge, but the low voltage protection circuits won't let us go near full discharge.
Exactly. When I flew rc / fpv, it was a pretty telling number (the input into the battery after a flight), as it gives you a real world accounting to what's going on.