Daymak Ultimate 60V Scooter

[khazdor]

Hi all

I just upgraded the SLA batteries in my Daymak Daytona to Ping's Battery pack. (will be posting on this tonight).

My question is :

How do I measure the Voltage/Amperage of it. With the SLAs, the meter that came with the bike was fairly accurate, but with the LiFePO in it, it's not exactly good. Is there an inexpensive meter that I can attach to the bike to serve the same function? Would like to do it so that I can figure out the Range on it.

Let me know
Thanks
Andre

 

[amberwolf]

Presumably the LiFePO4 battery has a BMS that will cut off discharge as soon as the pack is "empty". So you could just ride till the bike stops working and determine max range that way, then assume you will always have less than that available. Once you ride it that deeply discharged, you may have to leave it on the charger for a long time (sometimes days if it's not a great battery) to rebalance it, depending on how well-balanced it was to start with, and how good the cells actually are.



But there are a lot of cheap wattmeters around, and there's several threads discussing those, if you want to monitor the actual volts and amps and amp-hours and watt-hours too.

 

[dogman dan]

Yep, with lifepo4, just a simple voltmeter still tells you very little. So even one that reads in actual numbers won't help so much.

But a good wattmeter measuring the flow of electrons leaving your battery can do what you want. There are very affordable ones on ebay, but you will never regret going first class, and getting a stand alone model cycleanalyst.

 

[Nobuo]

usually watt meters stand 48V batteries max, if you battery is higher voltage you can use this one (>150V)

http://www.aliexpress.com/item/R-Founder-Battery-Capacity-Tester-Curve-Power-Meter-Watt-Meter-for-Tablet-Battery-and-phone-battery/1805183636.html

 

[granolaboy]

usually watt meters stand 48V batteries max, if you battery is higher voltage you can use this one (>150V)

http://www.aliexpress.com/item/R-Founder-Battery-Capacity-Tester-Curve-Power-Meter-Watt-Meter-for-Tablet-Battery-and-phone-battery/1805183636.html

I wonder if you could do an external shunt mod on that watt meter. Most of the watt meters don't have a calibration pot in them, so breaking out an external shunt throws the readings way off.

 

[amberwolf]

If you create some electronics to go between your external shunt and the point it would have been inside the meter, using op-amps, you could add your own calibration pot there. I don't know exactly what would be required, as it's been too long since I did any of that stuff, but it is possible to do.