Hello guys,
Just posting this as I've been going back and forth now for a while weighing up the pros and cons of different battery chemistries and formats to meet the needs of an electric kart.
LiPO for my use case is the best fit, its high discharge, high energy density, low sag, flat discharge curves, low weight and cycle life is good if properly cared for, but the problem of safety and high maintenance presents a problem.
Now safety I can solve by ensuring I use a reputable BMS and charging system to prevent over-discharge, under and over voltage and to have a protective shell around the cells.
The problem of maintenance comes in with storage voltage, LiPO suffers from degradation if stored at 100% and cycle life and performance over the lifetime of the cells decreases as a result, is there something I can do to combat this but keeping the simplicity of charging/storage?
Now I've looked at alternatives, 18650 lithium cells such as the Sony VTC5A and Samsung 20S look good except the steep discharge curve and voltage drop (Samsung 20S drops from 4.2 to 3.3v over the lifetime of the discharge) which is a major issue for performance and is something I can't seem to get around other than requiring them to be topped up constantly to prevent it during race events.
LifePo4 is another alternative but the extra weight required because of the lower voltage is an issue for a sport in which weight is a major component, but is a much safer chemistry.
Looking forward to hearing your opinions and help!
Just posting this as I've been going back and forth now for a while weighing up the pros and cons of different battery chemistries and formats to meet the needs of an electric kart.
LiPO for my use case is the best fit, its high discharge, high energy density, low sag, flat discharge curves, low weight and cycle life is good if properly cared for, but the problem of safety and high maintenance presents a problem.
Now safety I can solve by ensuring I use a reputable BMS and charging system to prevent over-discharge, under and over voltage and to have a protective shell around the cells.
The problem of maintenance comes in with storage voltage, LiPO suffers from degradation if stored at 100% and cycle life and performance over the lifetime of the cells decreases as a result, is there something I can do to combat this but keeping the simplicity of charging/storage?
Now I've looked at alternatives, 18650 lithium cells such as the Sony VTC5A and Samsung 20S look good except the steep discharge curve and voltage drop (Samsung 20S drops from 4.2 to 3.3v over the lifetime of the discharge) which is a major issue for performance and is something I can't seem to get around other than requiring them to be topped up constantly to prevent it during race events.
LifePo4 is another alternative but the extra weight required because of the lower voltage is an issue for a sport in which weight is a major component, but is a much safer chemistry.
Looking forward to hearing your opinions and help!