Lithium LiFePO4 Battery Load Testing on electric bike

Lithium Phosphate (LiFePO4) Battery Amp Load Testing on an electric bike

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Category:

Autos & Vehicles

Tags:

• Lithium
• Phosphate
• LiFePO4
• Crysalyte
• ebike
• electric
• bike
• an
• bicycle
• like
• wilderness
• energy
• crystalyte
• bionx
• Bionx
• Crystalyte
• eZee
• BMC
• NiMh
• Nano
• polymer
• 38.4v
• 48v
• 20Ah
• 10Ah
• EV

[zforce69]

I take it you mean that the motor controller is shutting down, not the battery.

[powerinmotion]

The battery had BMS (battery management system), if the BMS is programmed incorrectly, it will shut off (down) the power. Since our battery had an interface to the BMS, we can re-program the BMS.

[HolyCatholicApostoli]

@powerinmotion how does a SLA perform compared to the one's you have tested?

[powerinmotion]

SLA battery is 4 time heavy then lithium battery, SLA had a much faster dropping voltage. As a result, the mileage is poor. The only thing that SLA battery good is the price, but you will have replace more time. So lithium battery is the winner.

[moss1transcendant]

its rated at 3c :) 42point something volts fully charged.

[powerinmotion]

So a 20Ah and 3c rating is equal 60amp. Is the 3c rating a continuous rating or peak rate? You can certainly run two batteries in parellel, but I don't believe this solution. You are getting lithium battery because of the lighter weight, now you increase weight to over come the problem of the BMS or the battery problem. You might as well to stay with SLA or NiMh battery. Talk to us offline, we have the best lithium batteries for ebike.

[powerinmotion]

first of all, the kmx is very nice bike. This is a common problem that dealer who sell lithium do not test the limitation of battery and BMS. The purchase of BMS is to protect and regulate the battery. All BMS are programmed in the factory. Sometime they didn't program correctly, it will then over protected which result early cut-off, and if it is under protected, it will damage the cell. You need know your c-rating of the battery. I am running out of room here, I need second posting...

[moss1transcendant]

my bike is a kmx kart and is fairly heavy, that combined with my weight of about 260 lbs is a killer for the battery, i have a 36 volt 20 ah pack and a 650 watt motor which when i apply throttle i get upto 55 amp drain from battery and it cuts out so i can pull off. i asked about this at Cycle analyst website and a kind guy by the name of justin emailed me back mentioning i would need another battery.can i mearly buy matched one and add them togetherin parallel without messing up bms or cells?

[mrfukbag]

And how about voltage drop? Theres no way these batteries held the same voltage during your load test! Thus you could have been generating much more watts with the lipo then the nickel setup.

And do you really think that cheap cycle analyst gizmo is giving you RMS values? Its probably all over the map.

And by the way, in case you havent noticed. The whole world has changed over to lithium technology and soon ev's will all be lipo.

[mrfukbag]

there are no two cells, no two batteries, and no two BMS (from different manufacturers) that are alike. Therefore your test shows how your setup is effected by your cheap chinese bms.

Furthermore, how is your test realistic? Why would a person hold the motor back from spinning? its not designed to do that!

Any person who took shop class in school knows you need a prony brake to accuratly put a REALISTIC load on the setup to determine the charicteristics of the setup.