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  #1  
Old 04-04-2012, 11:28 AM
arn0 arn0 is offline
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Default Regen LiFePO4 with PM motor

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 ?

Thanks!
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  #2  
Old 04-04-2012, 11:36 AM
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frodus frodus is offline
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Default Re: Regen LiFePO4 with PM motor

Regen Current is proportional to the generator RPM

The motor voltage is boosted so that it matches the battery voltage and charges the batteries, so it doesn't matter what RPM you turn at, it'll still boost to pack voltage. But the higher the RPM, the more current you can charge the batteries.


What controller model are you looking at?

Careful going in reverse on the PMG motor, it's meant for one direction only.
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Old 04-04-2012, 11:54 AM
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Default Re: Regen LiFePO4 with PM motor

Thanks for your input.

I am already using the PMG 132 in reverse with 48V LeadAcid. According to it's datasheet, 48V is actually the limit to use it in both directions.

My current controller is giving me some issues, has limited power, and is not able to regen Lithium so I wanted to buy a new one with 200Amp continuous since the PMG can deliver 200Amps for 10minutes, but use only 110 Amp most of the time (and limit the 200A to some safety situation).

Since I need Reverse and Regen for my PMG132, as well as half-way throttle reverse, I only found that at Kelly.
I was particularly looking at the PM48501B.

If you know other controllers that match that would be good news too!
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Old 04-04-2012, 12:03 PM
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Default Re: Regen LiFePO4 with PM motor

Not a lot of regen controllers out there, honestly. Sevcon has one though.

Get a guarantee from Kelly if you buy one that they'll work with you on making it work and replace it if it blows up.
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Old 04-04-2012, 12:15 PM
arn0 arn0 is offline
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Default Re: Regen LiFePO4 with PM motor

Thanks, I checked Sevcon, it looks like a very good design, unfortunately I haven't find 48V DC PM controller with enough Amps (200) - correct me if I am wrong, I'd be happy to investigate the Lithium question with them.

Buy the way I am not jumping on Kelly since I don't know if it actually regen Lithium, meaning charging at constant voltage, securing the high and low voltages.

I have currently... no solution!
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Old 04-04-2012, 12:53 PM
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Default Re: Regen LiFePO4 with PM motor

200A peak regen?

yeah, talk to sevcon, not sure if that's doable.


Wouldn't 200A tend to load that engine down pretty good? that is a lot of regen.
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Old 05-05-2012, 10:34 AM
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Default

Sorry guys, my assumptions were wrong: voltage during regen is only 18V with diesel at 1800 rpm and 32V with diesel at 3200 rpm, with linear progression.
So I don't have overvoltage during regen, even if I slightly change the reduction ratio between the elec and diesel engines. Sorry for that.

I had my controller Bellmann CPM110-48 updated with lithium parameters and it works well. Still it is limited to 110A continuous and 150A 1 minute peak, I may upgrade in the future for more power (200A peak).
But this would be quite an investment for gaining only 50A peak.

And my main problem now is actually to reduce the load (size of the propeller) because the controller doesn't deliver the full voltage now (25V instead of 48, to limit the rpm due to the max torque under 110A).
So I am now actually using only 2.8kw instead of 5kw of the Perm PMG132.
Huge potential power gain here!

But... If I reduce the propeller it will be too small for the diesel and I would lose top speed under diesel mode.

Two solutions:
- higher reduction ratio between the 2 engines
- or install a controllable pitch propeller (smaller pitch with elec engine)

The two have their costs and difficulties.

I'll update you if interested

Thanks again for your help,
Arnaud
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