Current Confusion

Maybe because the kill a Watt is showing AC input and the cycle analyst is showing DC output.
You should compare actual Watts. (Volt x Amperes)

Use a 15 amp breaker of known good type and hook up a couple of 100 watt lights like a ceiling light fixture and VX-1 will trip the breaker. I notice mine says 12.9 or 13.0 amperes also. My circuit breaker trips out more often now so I know VX-1 is drawing a fair amount of current. When they recommend a 20 amp ckt, I guess they mean it. My outide outlet is just too easy to use. The breaker never trips unless ceiling light is on for an hour or so or I use anything more like a saw or drill or any tool. If I remember correctly you now have a bigger pack? A special pack of Lithium? More "current" needed to charge? How is your charging done? Constant current or contant voltage? Terminating voltage to BMS specs? Mine is stock NiMH 125 volt pack. If my XM-3000 accepts J-1772 inlet I will try it on VX-1. We now have three Coulomb chargers in our town. And I got a new coulomb card. My charger always goes for 3 hours and turns off. Then it does its 3 or 4 amp thingy later on in the cycle. I have a few 15 and 20 Amperes Simpson panel meters on my inside paower panel for monitoring frequency, watts, amps, and volts to see if I have a problem anywhere down the line. Plus I like to see if I have any problems. Good meters can be found on eBay to build your own monitoring system to verify Kill-A-Watt meter.

Maybe because the kill a Watt is showing AC input and the cycle analyst is showing DC output.
You should compare actual Watts. (Volt x Amperes)

His Majesty is right.

The volts from the wall are lower than the volts going into the pack (110ish vs. 142.9 (or whatever the CA is displaying)).

The CA is measuring what's going into the battery, the KAW is measuring what's coming out of the wall. The difference will be the efficiency of the charging system (where "system" includes everything between the two measurement points - not just the charger itself).

Set your KAW to the Watts display and you'll see somewhere close to 1500W (120V * 13A - but your KAW performs a better calculation than that so use it's Watts display). Calculate the Watts on the CA as Volts x Amps = 142.9 * 9.5 (about 1350W). Efficiency of your charging is then 1350/1500 = 90%. Which is excellent (OK, I think I must have my numbers wrong - I wouldn't expect it to be that efficient?)

An important extra point is that the efficiency calculated by this measurement is not your "true" efficiency because the charging process in the battery itself produces heat That heat is the result of inefficiency - think of it this way: you're putting 1350W of power into the battery but it's wasting say, 50W heating things up instead of storing the energy for later use.

JDH beat me to it about heat. And the longer the vehicle stays on the charger after the pack is full, the lower the overall efficiency and the higher the loss through heat. So use the Kill O Watt to see how much power you are using the keep your EV charged, and the Cycle Analyst to see how efficiently it uses that power on the road.

JDH beat me to it about heat. And the longer the vehicle stays on the charger after the pack is full, the lower the overall efficiency and the higher the loss through heat.

Hi Guys,

How are you measuring a heat rise?

Is it in the actual battery? or the BMS boards on top?
Or are we talking the charger? (the original charger's internal bias supply wastes ~50W the whole time its plugged in)

With most chemistry's heating of the battery is expected towards end of charge due to the presence of secondary reactions.

This is not the case for LiFePO4, as the secondary reactions that cause this heating all occur above 4.3v, and cause capacity loss

Charging at 10A should not cause any increase in temperature, as it is a very slow recharge rate (relatively speaking)

speaking of efficiency,

My long term average round trip efficiency is 84%.
That is: for every kwh the charger draws from the power point, the battery supplies 0.84Kwh to the Motor controller on discharge.

I use a TC Charger at 15A powered from nominal 230vac into a 42 x TS 60Ah battery.

Now that you have a kill-a-watt,
I was wondering if you could record the Wh used from the battery as reported from the cycle analyst, aswell as the kwh the charger draws from the power point on recharger?
A few charge discharge cycles would be great :)

cheers,
Matt