Need PDB for connecting 2 18S batteries. Not able to find PDB from vendors for 18S. Most of them support upto 14S

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Hello Team,

Need PDB for connecting 2 18S batteries. Have tried reaching out to Mauch - one of the renowned Vendors who do PDBs but they don’t seem to have PDB for connecting 2 18S batteries.

Currently risking integration of 2 batteries without a PDB. Both are connected in parallel through appropriate silicone cables of 4AWG and from there drawing out around 8 Pair of lines for propulsion unit with 8AWG cable. So the Joint(for distribution) is just a big soldering of wires with appropriate heat sink wraps. For instance, 2 Red-coloured 4AWG wire drawing current from 2-batteires is branched out to 8 Red-coloured 8AWG wire to drive propulsion and likewise for black.

Recommend which vendors to contact? Max current could go all up to 600A and average hover current is around 360-400A with 70V average.

Also the battery provides 2 lines for 5V/Gnd and 2 more lines for CAN-H and CAN-L So using those 5V/Gnd lines directly drives the peripherals. but the main concern is the implication of connecting two batteries without a PDB and the risk it poses for batteries, propulsion unit health.

Thanks

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Most PDBs at best have current monitoring and BECs they do nothing to protect batteries.

As long as you treat both packs as one unit and preferably check for voltage difference before connecting them to the system you should be fine even without the PDB.

You should try to minimize area between conductor pairs to minimize induced field.

I personally would use a dedicated BEC to power avionics as

  1. I would want to avoid different loads on packs.
  2. BECs typically shouldn’t be connected in parallel.
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Your response is valuable. Thank You

Without PDB isn’t there a possibility of Current being drawn from one battery more than other in spite of both batteries started off with same voltage? Will it result in non-uniform discharge?

How about sudden spike in current or drop in voltage from batteries? doesn’t pdb provide a more normalized output for propulsion system?

Yes. that is handled. will share a pic of it.

You meant a dedicated BEC along with a dedicated battery (lets say 3S) just to drive peripheral units?

Planning to connect 2 BECs to 5V/GND lines(which already I suppose is from internal BEC of the battery) of 2 18-S batteries. They will not be in parallel.