DIY Electric Car Forums banner

Regen LiFePO4 with PM motor

15331 Views 12 Replies 4 Participants Last post by  riwe
hi guys,

I'm struggling to understand if Kelly PM 48V controller can regen Lithium LiFePO4 or LiFeYPO4 batteries.

I have an parallel hybrid boat with a 18HP diesel on the same axel as the PERM PMG132.
I asked Kelly but I am very confused by the answer:
- they replied that the regen tension is proportional to the generator speed
- they put on their website that the controller "boost the regen voltage to the battery voltage" but that it can't cap the generator voltage if too high.

Has anyone here has a working configuration with Regen and Reverse, a PM motor and 48V LiFePO4 batteries ?

1 - 1 of 13 Posts
When in generator (powered by the Diesel engine at 3200 rpm), the PMG132 might turn at approx up to 5800 rpm (reductor between the 2 engines). So I suspect it can generate voltage around 100 V into the controller.
Hi arn0,

I think this will be a big problem. All of the available controllers for brushed PM motors are basically a buck converter for motor mode and a boost converter for regeneration. In motor mode, V_motor < V_bat. In generator mode, V_motor < V_bat. The same. If the motor voltage (as a generator) exceeds the battery voltage, the controller will fault, meaning shut down to protect itself. When the generator voltage is too high the controller has no means to regulate it.

  • Don't run the generator that fast.
  • Use a different controller for the generator designed to operate with high voltage input.
  • Change to wound field machine.
I don't think you will be pleased with the durability and service life of that motor running long periods at high RPM. 5800RPM may exceed the mechanical limit for that armature.

Interesting project. Where are you located (what nationality)?

See less See more
1 - 1 of 13 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.