PD 100W charger + DC-DC for 48V Battery Charging | Proof of Concept
Intro
Purpose: testing concept of using common laptop PD (Power Delivery) chargers for charging small vehicle (ebikes/scooters) batteries (36V/48V/72V) using USB-C to USB-C cable.
Reference
When searching for similar solutions I found that someone made the same thing, but he used another DC-DC and additonal voltmeter + 3D printed case:
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Source: https://www.youtube.com/watch?v=Lc7tHTDRtYM
Structural Block Diagram
Setup
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Connector
This ebike Li-Ion battery 13S (13*4.2V=54.6V) uses XLR (3-pin) connector.
Note: original charger rated for 5V, so Pmax=54.6V*3A=163.8W
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Test
Laptop PD charger 100W connected using USB-C to USB-C cable to USB PD trigger 20V and boost DC-DC converter with preconfigured voltage 54.6V (for 13S Li-Ion cells) and limited current. As a result we can see power from charger P=69W and battery charging current Icharging=1.428A
Conclusions
| 🟢 | Charging excellent works when current limited to prevent total power from charger exceed 100W. During test following values measured: Pcharger=69W and battery charging current Icharging=1.428A |
| 🟢 | This PoC shows that using specialized I2C buck-boost 1S-14S BQ25750 charger is right choice for portable USB PD battery charger |
| 🟡 | Original charger rated for Pmax=54.6V*3A=163.8W while common USB PD chargers for Pmax=100W |
| 🟡 | Different vehicle batteries use different connectors, so XT60 + additional cable is the best solution for future charger |