With my newest e-bike almost complete I've decided to order a couple of batteries from Li Ping plus some diodes. I intend to go the diodes route in parallel connecting two 48V 20Ah packs.
And with this in mind I asked Li Ping about the involved wiring and whether the packs could be charged while remaining parallel connected [ charged separately ].
Li Ping replied by sending to me a wiring schematic showing the diodes placement and orientation on the positive discharge wires.
Additionally, he wrote…
Hi Gary,
If the discharge wires are connected in parallel with the diodes, it’s fine to charge them with two chargers. The diodes are just avoiding the current between the two packs through the discharge wires when they’re connected in parallel. So, if the diodes are connected, it’s ok to charge them together.
Best regards,
Ping
And the question I have relates to the fact that there are both positive and negative discharge wires on each pack and only the positive of each plays host to a diode. And, so, is it feasible that charging while the packs are still parallel connected could result in potentially damaging cross currents via the negative wires?
And with that asked here's a passage from additional material provided me by Li Ping...
If you don’t want to use the diodes, it’s feasible.
However, please make sure these two packs are in same charge level when you
connecting them in parallel.
For example, if one pack is 50% charged and the other is 90% charged, the 90%
charged pack will charge the other pack when you connecting them in parallel. The
charging current in a short period of time could be huge and harmful to cells in both packs.
The easiest way to avoid it is to fully charge both packs before connecting them.
Also, please disconnect the packs when they’re charged, although they’re charged
through a separate pair of wires, because one pack could be charged higher than the
other. If they’re connected together in parallel, the higher pack will charge the lower
through discharge wires. Furthermore, if some of the cells in the lower pack have been full,
they could be over-charged by the higher pack, because there’s no over-charge protection
on the discharge wires.
Thanks for any/all help.
And with this in mind I asked Li Ping about the involved wiring and whether the packs could be charged while remaining parallel connected [ charged separately ].
Li Ping replied by sending to me a wiring schematic showing the diodes placement and orientation on the positive discharge wires.
Additionally, he wrote…
Hi Gary,
If the discharge wires are connected in parallel with the diodes, it’s fine to charge them with two chargers. The diodes are just avoiding the current between the two packs through the discharge wires when they’re connected in parallel. So, if the diodes are connected, it’s ok to charge them together.
Best regards,
Ping
And the question I have relates to the fact that there are both positive and negative discharge wires on each pack and only the positive of each plays host to a diode. And, so, is it feasible that charging while the packs are still parallel connected could result in potentially damaging cross currents via the negative wires?
And with that asked here's a passage from additional material provided me by Li Ping...
If you don’t want to use the diodes, it’s feasible.
However, please make sure these two packs are in same charge level when you
connecting them in parallel.
For example, if one pack is 50% charged and the other is 90% charged, the 90%
charged pack will charge the other pack when you connecting them in parallel. The
charging current in a short period of time could be huge and harmful to cells in both packs.
The easiest way to avoid it is to fully charge both packs before connecting them.
Also, please disconnect the packs when they’re charged, although they’re charged
through a separate pair of wires, because one pack could be charged higher than the
other. If they’re connected together in parallel, the higher pack will charge the lower
through discharge wires. Furthermore, if some of the cells in the lower pack have been full,
they could be over-charged by the higher pack, because there’s no over-charge protection
on the discharge wires.
Thanks for any/all help.