Wednesday, November 8, 2023

Re: [electricboats] Parallel LiFePO4 Packs

Connecting two 230Ah cells together in parallel (sixteen times) would allow you to treat the 32 cells as one large 16S 48V x 460Ah battery
BMS, load, charger, capacity monitoring would be none-the-wiser.

One concern of that configuration that wouldn't otherwise come up is if one cell in a two-cell pair were to fail.
If the failure is a short, it would bring the other cell with it.

From: electricboats@groups.io <electricboats@groups.io> on behalf of ChristopherH via groups.io <clh5_98=yahoo.com@groups.io>
Sent: Wednesday, November 8, 2023 10:34 AM
To: electricboats@groups.io <electricboats@groups.io>
Subject: [electricboats] Parallel LiFePO4 Packs
 
Hi Group,
My Morgan Out Island 41 is ready for new batteries. I'm ready to embrace LiFePO4. When I originally converted to electric I built and glassed in 2 battery boxes to hold 2 banks of 8 (16 batteries) golf cart batteries. I always run with both banks in parallel, but have the ability to run on just 1 and this has worked well. Unfortunately this size battery box doesn't make efficient use of most individual LiFePO4 cells. I would however be able to use 32 X 230Ah EVE cells in 1 battery box, leaving the other box for some other purpose. My questions: I'd like to be able to run the 2 X 16S strings in parallel. Is this possible with LiFePO4? Is it safe to do this? Any precautions? Would I have 2 separate BMS units? How about capacity monitoring for the 2 banks in parallel? I have a Victron 48V/5KVA Victron Quattro charger inverter. 
Thanks in advance for any assistance/suggestions.

Regards,
Chris Hudson

Sent from myPhone





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[electricboats] Parallel LiFePO4 Packs

Hi Group,
My Morgan Out Island 41 is ready for new batteries. I'm ready to embrace LiFePO4. When I originally converted to electric I built and glassed in 2 battery boxes to hold 2 banks of 8 (16 batteries) golf cart batteries. I always run with both banks in parallel, but have the ability to run on just 1 and this has worked well. Unfortunately this size battery box doesn't make efficient use of most individual LiFePO4 cells. I would however be able to use 32 X 230Ah EVE cells in 1 battery box, leaving the other box for some other purpose. My questions: I'd like to be able to run the 2 X 16S strings in parallel. Is this possible with LiFePO4? Is it safe to do this? Any precautions? Would I have 2 separate BMS units? How about capacity monitoring for the 2 banks in parallel? I have a Victron 48V/5KVA Victron Quattro charger inverter.
Thanks in advance for any assistance/suggestions.

Regards,
Chris Hudson

Sent from myPhone


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Re: [electricboats] sevcon controlled electric drive does not rotate

The RMB29 datasheet says it has conformal coating.  For more challenging environments I would add a Silicon coating like Dow Corning 3-1765 or 3-1953 avoiding excess buildup on on the IC body
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Tuesday, November 7, 2023

Re: [electricboats] sevcon controlled electric drive does not rotate

Yes !
 
You need to power the board: with the controller switched on, or disconnect the sensor and use an external +5V supply.
 
Then, with an oscilloscope and by turning the motor, you can see the sine and cosine waves on the oscilloscope screen.

(Take a look at : https://www.kit-elec-shop.com/gb/brand/126-rls )
 
Thierry
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Re: [electricboats] sevcon controlled electric drive does not rotate

is there a way to test the board on the motor?
TIM HOOPER
DIRECTOR
____
 
t   03 9690 2788
f   03 9690 2899
w acumendesign.com.au
 
 
6/132 Bank St
South Melbourne
Victoria 3205
 
acumen

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Re: [electricboats] sevcon controlled electric drive does not rotate

Yea 9 times out of 10 its the encoder (position sensor) that fails and if the motor gets they will get wet and fail. Always good to have a spare on board. If you install the replacement carefully you can usually get away with not needed to reprogram the controller. 

 For this reason I'm a fan of sensor less motors on boats. There is no advantage to have a sensored motor thats only a  prop.  

Matt Foley 
Sunlight Conversions
Perpetual Energy, LLC
201-914-0466

ABYC Certified Marine 
Electrical Technician 


On Tuesday, November 7, 2023 at 01:59:00 PM EST, Myles Twete <matwete@comcast.net> wrote:


Interesting to learn that the angular position sensor boards have this level of failure rate.

On balance, my 20yr old ETEK brush motor (on 4th set of brushes) setup doesn't look so bad even today with so many seasoned brushless alternatives.

I did have an Alltrax AXE controller fail this summer (after 20 years), but that was probably my fault.

I replaced it with a used one bought on Ebay (Alltrax NPX) which didn't deliver close to the battery voltage let alone its rated full power.  Thankfully, Alltrax agreed to reflash the memory in the controller and changed the throttle type to ITS (inductive throttle sensor) for me and it's been working like a charm since.  No idea why but even while it acknowledged full throttle it would only output about ¾ battery voltage to the load.  That used controller was a boat-anchor if it weren't for Alltrax doing this for me.

 

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of jeffsschwartz@hotmail.com
Sent: Tuesday, November 7, 2023 8:46 AM
To: electricboats@groups.io
Subject: Re: [electricboats] sevcon controlled electric drive does not rotate

 

Hi Tim,

I had the same problem a couple of years back with my Sevcon/Motenergy combo (purchased from Thunderstruck).  It all worked great when I benched it and then it stopped working later on (the motor would vibrate a bit but not spin).  The problem ended up being the controller board in the engine (the Motenergy one costs about $30 US).  When Thunderstruck shipped me a new board it worked fine and I haven't had a problem since.

The controller board is in the back of the Motenergy motor, under a small screwed in panel.  I may have a picture from some previous emails that I can dig up.

Posted by at No comments:

Re: [electricboats] sevcon controlled electric drive does not rotate

Interesting to learn that the angular position sensor boards have this level of failure rate.

On balance, my 20yr old ETEK brush motor (on 4th set of brushes) setup doesn't look so bad even today with so many seasoned brushless alternatives.

I did have an Alltrax AXE controller fail this summer (after 20 years), but that was probably my fault.

I replaced it with a used one bought on Ebay (Alltrax NPX) which didn't deliver close to the battery voltage let alone its rated full power.  Thankfully, Alltrax agreed to reflash the memory in the controller and changed the throttle type to ITS (inductive throttle sensor) for me and it's been working like a charm since.  No idea why but even while it acknowledged full throttle it would only output about ¾ battery voltage to the load.  That used controller was a boat-anchor if it weren't for Alltrax doing this for me.

 

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of jeffsschwartz@hotmail.com
Sent: Tuesday, November 7, 2023 8:46 AM
To: electricboats@groups.io
Subject: Re: [electricboats] sevcon controlled electric drive does not rotate

 

Hi Tim,

I had the same problem a couple of years back with my Sevcon/Motenergy combo (purchased from Thunderstruck).  It all worked great when I benched it and then it stopped working later on (the motor would vibrate a bit but not spin).  The problem ended up being the controller board in the engine (the Motenergy one costs about $30 US).  When Thunderstruck shipped me a new board it worked fine and I haven't had a problem since.

The controller board is in the back of the Motenergy motor, under a small screwed in panel.  I may have a picture from some previous emails that I can dig up.

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