Hi together,
after watching Will’s second video on LTO batteries I thought I share my LTO/BCAP replacement built for my car.
Since my car used to eat up lead batteries roughly every two years, my initial idea was to build a replacement with BCAPs only as I was not convinced by LiFePO4 car batteries due to their limited high current capabilities. Since the LTO cells became reasonable priced lately I added the LTO cells to the setup.
The setup consists of the following components:
The capacitors and the batteries are connected in a serial/parallel configuration to allow for a single balancer setup and having the capacitor leackage current directly compensated by the battery cells.
The active balancer keeps the voltage difference within 10mV and is rated at a maximum balancing current of 5A. Additionally I connected an IDST BG-8S to monitor the cell voltages though it has no direct LTO support currently.
The capacitors are interconnected with 25x5mm copper bars while the rest of the cells are connected with 35mm2 equivalent copper bars.
So far I measured a maximum current of 410A at the battery while cranking the cold engine with the voltage dropping to 12.5V at the battery terminals (initially charged to 13.6V).
After now 3 weeks of driving with the battery I am very happy with the replacement.
The major draw backs I see with using LTOs (in combination with BCAPs) are:
Philipp
after watching Will’s second video on LTO batteries I thought I share my LTO/BCAP replacement built for my car.
Since my car used to eat up lead batteries roughly every two years, my initial idea was to build a replacement with BCAPs only as I was not convinced by LiFePO4 car batteries due to their limited high current capabilities. Since the LTO cells became reasonable priced lately I added the LTO cells to the setup.
The setup consists of the following components:
- 6x Yinlong LTO66160H 40Ah
- 6x Maxwell BCAP3000
- 6s 5A LTO active balancer
The capacitors and the batteries are connected in a serial/parallel configuration to allow for a single balancer setup and having the capacitor leackage current directly compensated by the battery cells.
The active balancer keeps the voltage difference within 10mV and is rated at a maximum balancing current of 5A. Additionally I connected an IDST BG-8S to monitor the cell voltages though it has no direct LTO support currently.
The capacitors are interconnected with 25x5mm copper bars while the rest of the cells are connected with 35mm2 equivalent copper bars.
So far I measured a maximum current of 410A at the battery while cranking the cold engine with the voltage dropping to 12.5V at the battery terminals (initially charged to 13.6V).
After now 3 weeks of driving with the battery I am very happy with the replacement.
The major draw backs I see with using LTOs (in combination with BCAPs) are:
- using 6 cells in series for a voltage of 13.8V keeps the cells well below the maximum possible capacity/charge - I assume that in this setup, the battery has only 20Ah when fully charged rather than 40Ah possible
- high current load on the alternator when discharged potentially damaging the alternator at low RPM - since the alternator is water cooled in this car I am currently neglecting this aspect
- more expensive than LiFePO4
- 20,000+ cycles for LTO cells and 1,000,000 cycles for the capacitors
- high current capability
- save chemistry
Philipp