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--- astra_conv:conversion:battery_charger:battery_charger [2014/03/13 23:25]
richard
+++ astra_conv:conversion:battery_charger:battery_charger [2014/05/20 17:59] (current)
richard
@@ Line 4: / Line 4: @@
 The battery charger, which I got via Marco Lorey, had it's characteristics already adapted for a 30 cells Lithium battery.
-The charger delivers 15 Amps at maximum. Unfortunately, with the given characteristics it would not charge the eight provisional 12V lead-acid batteries you see on below picture. Their charging voltage was too high. It might have worked with only 7 of them, but of course at the risk of a gentle explosion in case of inadvertent overcharging.
+The charger delivers 15 Amps at maximum. Unfortunately, with the given characteristics it would not charge the eight provisional 12V lead-acid batteries you see on below picture. Their charging voltage was too high. It might have worked with only 7 of them, but of course at the risk of a decent explosion in case of inadvertent overcharging.
 {{:astra_conv:conversion:battery_charger:p1100325.jpg?800|}}
+During the charging process, the charger and the BMS will closely work together:
+The 15A charging current will be applied up to a certain first threshold voltage, and the device remembers the time to reach the first threshold. The device will then continue charging at a reduced current (around 1A) till either a second threshold voltage is reached, a BMS (HVC) alarm occurs or the time of the second charging phase exceeds half of the first charging phase. This trickle charging phase is utilized by the BMS system in order to balance the state-of-charge of the individually cells, by shunting those cells exceeding a certain voltage (around 3.6V).
+The charging current is slightly higher than the maximum shunting current, so that in case of imbalance, the  voltage of a certain cell may eventually reach 3.7V, where the cell module will create a "HVC" event and interrupt the cell loop.
 Below, for orientation only, a clipping of the wiring diagram. It will not indicate the peers of all connections, and it may be outdated. Please refer to [[astra_conv:conversion:wiring:wiring#wiring_diagram]] for a comprehensive and uptodate view.
@@ Line 35: / Line 40: @@
 {{:astra_conv:conversion:battery_charger:p1100018.jpg?400|}} {{:astra_conv:conversion:battery_charger:p1100027.jpg?400|}}
+Originally, the charger was directly bolted to the car chassis. Since it turned out to be quite noisy, I later suspended it in rubber mounts to reduce the noise radiated from the car's floor to the outside.
+DIY rubber mount: The mounting hole of the charger is drilled out and the inner tube is inserted. The two rings of outer tube are then placed the inner tube, on top and beneath the charger's mounting plate. A bolt with a large washer is inserted into the inner tube, and presses the whole mount to the chassis.
+{{:astra_conv:conversion:battery_charger:p1110727.jpg?600|}}
 In order to protect the charger's ventilation holes from the ECE R-100 test wire, I built a cage made of expanded metal mesh.

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