VEC500 overheating

[AntsaS]

Hi all,

Recently replaced my boat's old diesel engine with GM 48v BLDC motor, but very soon after install of the motor I found out that VEC is overheating.
I can drive ~1h with usage of ~1500w before controller overheat protection is kicking in.
Heating is only limited to controller, cables and motor itself are not heating significantly.

My setup:
- 48v fan cooled BLDC motor
- VEC500 controller
- 4*12v 200Ah lead acid batteries

Any ideas?

Thanks,
Antti

[Bikemad]

Hi Antti,

If the controller is overheating, you will need to improve the heatsink to enable it to dissipate the unwanted heat more efficiently.

A water cooled heat sink plate would appear to be the obvious solution in a boat:



Alternatively, a suitable air cooled heat sink (with electric fan for improved airflow) should be able to cool the controller sufficiently to prevent overheating:



A bit more information could be beneficial to other members contemplating a similar conversion:

What size boat have you converted?
(Model, type, length, weight/displacement etc.)

How many HP did the old diesel motor produce?

Are you using the 10kW motor?

What is the gear ratio between motor and propshaft?

Diameter and pitch of prop?

Top speed and average cruising speed etc.?

Hopefully you can find the time to answer these questions and post some pictures of the conversion too.



Alan
 

[AntsaS]

Thanks for the help Alan!
Seems like I'll choose water cooled heat sink.

A bit info about my boat:
Boat is old Ohlson 29 80'
-Length 29ft
-Weight 3300kg
https://drive.google.com/drive/folders/0B3mWc0R7ybT3YlYwWXJCTlNTZjA

Old engine is Yanmarin YSM8 (8hp), loud one cylinder smoker 

New motor is 10kw BLDC +[/img] 5hp four stroke as a spare engine.

New BLDC is attached directly propeller shaft with flexiple coupler. It's not ideal to not use gear reduction, but wasn't able to get parts before start of sailing season. Plan is to fix this when winter comes again.

Don't have much to say about propeller since don't know details. Typical folding propeller which is commonly used in sailboats.

Average cruising speed is 4-5knots, haven't tried full speed yet but record so far with 5kw consumption was ~7knots
With 20Ah consumption I can reach 5 hour of constant cruising with speed of 3-4.5knots.

Here is a short video from test run. Don't mind about mess, things are still looking for their place
https://drive.google.com/file/d/0B3mWc0R7ybT3d0h1S0lhQ1A3TkU/view?usp=sharing

Cheers,
Antti

[Rusina]

Hello Anti,
I had the same problem of overheating my VEC 500 with a GM 10 kW
I have created a water + glycol cooling circuit in copper coil against the radiator and I manage to maintain the temperature below the controller safety.
You can even use it to warm up your sanitary water via an exchanger.
On the other hand, I operate with a double chain transmission and I installed a thrust bearing on the propeller shaft, not to exert the thrust on the engine, which is not terrible in the long term.
Finally, I finally think, but it is to verify, that the torque necessary for propulsion is too large not to use a reduction and that is what makes the controller heat, which is a loss of efficiency Not negligible in thermies.
I have to leave my boat, and will try to find the double gear to go towards a 2: 1 reduction, and in a month I will do a new series of tests.
Nautical greetings.

[Rusina]

Ha, I forgot: can you tell me the brand, model and price of the monitor seen on your video to monitor the instant power and amperage used by your engine?