T-Pain Is On A Boat: November 2023

Wednesday, November 22, 2023

Re: [electricboats] Parallel LiFePO4 Packs

I don't know if it is general knowledge that fully charged LFPO batteries must be disconnected from a charging source. Lately I have heard of some unexplained fires in boats that are docked while their owners are absent and have wondered if the batteries were being over charged by solar panels or wind. The BMS should be set up to physically disconnect the batteries.

This can be complicated by solar and wind if these sources must be redirected to another load path to consume this unwanted charging current.

Hopefully, Everyone is hearing old news

On Tue, Nov 21, 2023 at 10:07 AM THOMAS VANDERMEULEN <tvinypsi@gmail.com> wrote:

wow, Reuben ... ! A full MegaWatt hours of capacity?!?! According to one source, that's enough to power the average household of 5-weeks!!
What is your cruising range on motor alone? Must be close somewhere around 70 Nautical Miles.
[-tv]

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Tuesday, November 21, 2023

Re: [electricboats] Parallel LiFePO4 Packs

12m - over 20,000# - has 5kW solar - 2 each 10kW Motenergy water-cooled motors

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Re: [electricboats] Parallel LiFePO4 Packs

My mistake, entirely, Reuben ... thanks ... but even at 50kWh, it's still a very substantial pack!! Given a range of 25NM, then, I gather it's a very substantial boat as well.
Fair winds!
[-tv]

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Re: [electricboats] Parallel LiFePO4 Packs

That's what I have in my Tesla :)

On 11/21/23 12:28 PM, Reuben Trane via groups.io wrote:

Check your math? 1,000AH/48v is 50kWh. I get about 25NM at 5 knots.

--   Jeff LaCoursiere  StratusTalk, Inc.  703 496 4990 x108  815 546 6599 cell

Re: [electricboats] Parallel LiFePO4 Packs

Check your math? 1,000AH/48v is 50kWh. I get about 25NM at 5 knots.

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Re: [electricboats] Parallel LiFePO4 Packs

wow, Reuben ... ! A full MegaWatt hours of capacity?!?! According to one source, that's enough to power the average household of 5-weeks!!
What is your cruising range on motor alone? Must be close somewhere around 70 Nautical Miles.
[-tv]

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Re: [electricboats] Electric motor size for 48' cat

Hey Jack,

Thanks for that info! That's a pretty close comparison, so that's very helpful. More and more, I'm thinking the Thunderstruck 12k package at 48v seems like the right fit.

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Monday, November 20, 2023

Re: [electricboats] Parallel LiFePO4 Packs

Hi Chris,
I know what you mean meaning having the flow through the BMS unit rather than it control a relay, but what turned me is that with the daly unit you can set limits to cut charging but still have discharging going, which i found to be a good fail safe / back up, rather than just drop the relay and the bank should something go amiss. I think my thought process for my set up tends to be wavered by my background in the O&G industry, we have back ups for back ups. hence i like the idea of the 48V 2 banks which can run together or individually for propulsion. We are also having a independent 12 volt bank for the rest of the boat as another back up :-)

good luck with getting it all sorted and let me know how it all goes

cheers
kel

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Re: [electricboats] Parallel LiFePO4 Packs

Hi mate
the daly BMS has 300, 400 and 500A version in the EV/Boat range, when you run 2 BMS's you then add a parallel module to each one.
my motors are twin 48V / 15kW , 1,000AH impressive :-)

cheers
kel

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Re: [electricboats] Parallel LiFePO4 Packs

I would avoid Daly. They have a nice website, tons of videos, ect. I consider most of it vaporware. It simply doesn't work as its supposed to or just doesn't work. If you have any chance of the cells balancing, you need to buy the cell balancer.

On top of that, they just don't last long. Forums are littered with comments from people went through multiple Daly products before they gave up and bought something else.

I don't think their parallel protector is needed or does anything.

Check out JK BMS.

Matt Foley

Sunlight Conversions

Perpetual Energy, LLC

201-914-0466

sunlightconversions.com

instagram.com/sunlightconversions/

youtube/sunlightconversions

ABYC Certified Marine

Electrical Technician

On Monday, November 20, 2023 at 12:32:01 PM EST, Kel Bryant <kelbryant@hotmail.com> wrote:

Hi Chris
I am building a 47ft cat with 2 x ME1616 motor, am going to install 2 x 16 string 304ah banks in parallel, mainly for a back up should we have a problem, we are going to use 2 x BMS's with active balancing and a parallel protector Daly BMS have such an animal, which from my research seems to fit the bill, my 48 bank / banks will also charge on 12 volt house bank which is 300ah via a DC-DC charger and another BMS,

cheers
kel

https://www.dalybms.com/daly-smart-bms-500a-with-bt-touching-display-for-low-speed-car-rv-boat-product/

Re: [electricboats] Parallel LiFePO4 Packs

Hi Kel,

Thanks for that. I did see the Daly Pack Parallel Module. I have not been able to get comfortable with the BMS units where the charge and discharge current is passed through and regulated by it. I've settled on 1 string of cells at 304 Ah for now. I bought a REC 2Q BMS that just controls a contactor to interrupt charging/discharging if parameters get out of bounds. I like this way because it's easy to bypass the contactor in a pinch. REC do have the ability to parallel strings. I think (not sure) it would be 2 BMS plus a master module. I finally just had to get off the fence and do something, so I took the easy way out and went with a single string.

Chris

Sent from myPhone

On Nov 20, 2023, at 16:41, Reuben Trane via groups.io <rjtrane=me.com@groups.io> wrote:

Does the Daly BMS allow for 200A current - I'm guessing your motors are 48v/10kW?

I have twins in my cat but a single 1,000AH/48v pack with Winston cells - 16s. Much simpler than two packs.

what model Daly handles parallel connections safely

Re: [electricboats] Parallel LiFePO4 Packs

Does the Daly BMS allow for 200A current - I’m guessing your motors are 48v/10kW?

I have twins in my cat but a single 1,000AH/48v pack with Winston cells - 16s. Much simpler than two packs.

what model Daly handles parallel connections safely

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Re: [electricboats] Motor recommendation

I’d think a 48v/10kW or 12kW is big enough. Check the kits at thunderstruck-EV. com. They may have good recommendations for your boat. I have a pair if 10kW Motenergy water cooled with Sevcon Gen4 controllers and the Thunderstruck motor mounts/reduction pulleys. My cat is 40’ and over 20,000#.

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Thursday, November 9, 2023

[electricboats] Motor recommendation

I have a Sabre 28-2 with a 30 hp Atomic 4 engine. What size electric motor should I consider?

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Re: [electricboats] Parallel LiFePO4 Packs

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Re: [electricboats] Parallel LiFePO4 Packs

Stew,

Thanks for the input. Check out The Off Grid Garage on YouTube. This guy has done a lot of testing with parallel banks and parallel cells. His testing makes it look like it's no big deal. He's also very entertaining.

Chris

Sent from myPhone

On Nov 9, 2023, at 11:16, Stew <stewart.reed@free.fr> wrote:

Interesting article - thanks for posting - needs a few reads to fully understand!
I have had 2 x 16s sets in parallel (2 x 16 272Ah lifepo4 cells) set up with an Overkill 16s bms for each. I run them together but can switch out either bank if required. The bms allows monitoring of all cells.
The article has made me wonder whether I should rethink and set up as a single bank with cells paired but not sure to be honest. Probably will do more testing as is to see if any limitations.
Installed in a Jeanneau 36' GinFizz with ME1616 motor and Sevcon 6 controller.

Re: [electricboats] Parallel LiFePO4 Packs

Interesting article - thanks for posting - needs a few reads to fully understand!
I have had 2 x 16s sets in parallel (2 x 16 272Ah lifepo4 cells) set up with an Overkill 16s bms for each. I run them together but can switch out either bank if required. The bms allows monitoring of all cells.
The article has made me wonder whether I should rethink and set up as a single bank with cells paired but not sure to be honest. Probably will do more testing as is to see if any limitations.
Installed in a Jeanneau 36' GinFizz with ME1616 motor and Sevcon 6 controller.

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

The motor itself is not sealed well enough, and in this saildrive orgintion water can collect on the top of the motor and seep in .

The 4 screws that hold the encoder down can also short out the board, it helps to put fiber washers under these . Sometimes just removing the screws fixes the encoder problem.

Brian D. HAll


	ThunderStruck Motors, LLC 2985 Dutton Ave. Ste 3 Santa Rosa, CA 95407 Tel: (707) 578-7973 Fax: (707) 581-1860

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[electricboats] San Juan 24

Anybody interested in a San Juan 24 in the seattle area?

Cheap

Needs a motor

Cheers

Re: [electricboats] Parallel LiFePO4 Packs

Thanks guys. I've been watching some YouTube videos from the Off Grid Garage. The guy is doing parallel 48 volt strings. I'm warming back up to the idea of doing just this. Need to do some more research, but this seems possible and safe.

Chris

Sent from myPhone

On Nov 8, 2023, at 21:05, Myles Twete <matwete@comcast.net> wrote:

Or you can go with 2 strings, 2 BMS and combine the strings like you originally talked about. But you don't have to make these formally "switchable" strings---they can be segregated for emergency or other reasons (e.g. separate charging) very easily with appropriate connector choices. Fuses are always a good idea.
My pack is effectively composed of 20 separate nom. 42v strings all combined in parallel thru 20amp fuses.
That would ordinarily be a very expensive and complicated way to go (especially given also the 20 remote BMS cards I use) but the strings are comprised of modules including BMS cards that are ex-EV and relatively inexpensive.
So not counting cabling and fuses, one can pick up modules like this (including BMS cards) for $50/kwh or even less if you cut out the retailer. I paid about this for the latest modules I picked up and could have gotten them for about half that.
So in my case, if I suddenly had a shorted cell (internal or external short), that string's fuse would blow and it would be some time before I'd discover it---eventually I'd discover it, but in the meantime that string would be isolated. In several years of use (lithium ion) I have yet to see a shorted cell pair, though I do know there are several weaker or leaky cell pairs out of the 240 cell pairs in the pack. Also, I can quickly isolate any or many strings by simply slipping off any particular "Radsok" connectors at the top of each stack. The Radsok connectors also makes it quick and easy to remove one of the modules.

If these USED batteries were not available cheap, I'd probably still be running with flooded PbA or would have gone with a single- or dual-string LiFePo large-capacity pack as you are planning.

-MT

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of ChristopherH via groups.io
Sent: Wednesday, November 8, 2023 2:26 PM
To: electricboats@groups.io
Subject: Re: [electricboats] Parallel LiFePO4 Packs

I found this great article by Orion BMS that discusses parallel strings. Reading this really makes me lean toward parallel cells as you wise gents previously suggested.

Thanks again for all the valuable input.

Chris
<image002.png>
parallel_strings
PDF Document · 408 KB

Sent from myPhone

On Nov 8, 2023, at 16:58, ChristopherH via groups.io <clh5_98=yahoo.com@groups.io> wrote:

Reuben,
From what I've seen, Victron only have BMS for their line of packaged batteries in the 12 and 24 volt ranges.

Chris

Sent from myPhone

On Nov 8, 2023, at 16:55, Chris Hudson <clh5_98@yahoo.com> wrote:
John,
Thanks for your input and good point about having an ace in the hole!
Chris

Sent from myPhone

On Nov 8, 2023, at 16:22, john via groups.io <oak_box=yahoo.com@groups.io> wrote:

I don't have a LOT of experience with this, but am now running my electric dinghy with two separate 48V ebike batteries.

I like keeping them separate so that if one gets accidentally discharged (or any other failure), I still have a second battery to get home on.

On Wednesday, November 8, 2023 at 01:59:35 PM CST, Myles Twete <matwete@comcast.net> wrote:

Thought: Dangerous for the switch unless it's a break-before-make or other exclusive-or arrangement.

Why: You've been running for hours on one string, then decide to switch to the other. If you thought that you'd just use a standard marine battery combiner switch, you could accidentally switch to "ALL" position, which would then put both strings in parallel thru the switch, quickly shorting it and possibly melting the housing. Might also have a problem with that type of switch switching between each string.

With Lithium-Ion there's something to be said for having separate strings---ability to switch and get a higher pack voltage again for a time giving higher power/speed than if the strings were paralleled and slowly going down together. But really, a slowly dropping voltage is better than one that drops much faster due to not paralleling. Not as much of a big deal with LiFePo, but still, I'd tend to think paralleling is better.

Just a thought.
-MT

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of ChristopherH via groups.io
Sent: Wednesday, November 8, 2023 11:49 AM
To: electricboats@groups.io
Subject: Re: [electricboats] Parallel LiFePO4 Packs

Bobkart,
Thanks for the reply. Actually I'm proposing to have 2 independent 16 cell strings with the ability to parallel them at the 48V level with switches, not at the cell level. Thoughts on that?

Chris
Sent from myPhone

On Nov 8, 2023, at 14:40, bobkart <couch45@msn.com> wrote:

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

Wednesday, November 8, 2023

Re: [electricboats] Parallel LiFePO4 Packs

Or you can go with 2 strings, 2 BMS and combine the strings like you originally talked about. But you don't have to make these formally "switchable" strings---they can be segregated for emergency or other reasons (e.g. separate charging) very easily with appropriate connector choices. Fuses are always a good idea.

My pack is effectively composed of 20 separate nom. 42v strings all combined in parallel thru 20amp fuses.

That would ordinarily be a very expensive and complicated way to go (especially given also the 20 remote BMS cards I use) but the strings are comprised of modules including BMS cards that are ex-EV and relatively inexpensive.

So not counting cabling and fuses, one can pick up modules like this (including BMS cards) for $50/kwh or even less if you cut out the retailer. I paid about this for the latest modules I picked up and could have gotten them for about half that.

So in my case, if I suddenly had a shorted cell (internal or external short), that string's fuse would blow and it would be some time before I'd discover it---eventually I'd discover it, but in the meantime that string would be isolated. In several years of use (lithium ion) I have yet to see a shorted cell pair, though I do know there are several weaker or leaky cell pairs out of the 240 cell pairs in the pack. Also, I can quickly isolate any or many strings by simply slipping off any particular "Radsok" connectors at the top of each stack. The Radsok connectors also makes it quick and easy to remove one of the modules.

If these USED batteries were not available cheap, I'd probably still be running with flooded PbA or would have gone with a single- or dual-string LiFePo large-capacity pack as you are planning.

-MT

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of ChristopherH via groups.io
Sent: Wednesday, November 8, 2023 2:26 PM
To: electricboats@groups.io
Subject: Re: [electricboats] Parallel LiFePO4 Packs

I found this great article by Orion BMS that discusses parallel strings. Reading this really makes me lean toward parallel cells as you wise gents previously suggested.

Thanks again for all the valuable input.

Chris

parallel_strings

PDF Document · 408 KB

Sent from myPhone

On Nov 8, 2023, at 16:58, ChristopherH via groups.io <clh5_98=yahoo.com@groups.io> wrote:

Reuben,
From what I've seen, Victron only have BMS for their line of packaged batteries in the 12 and 24 volt ranges.

Chris

Sent from myPhone

On Nov 8, 2023, at 16:55, Chris Hudson <clh5_98@yahoo.com> wrote:
John,
Thanks for your input and good point about having an ace in the hole!
Chris

Sent from myPhone

On Nov 8, 2023, at 16:22, john via groups.io <oak_box=yahoo.com@groups.io> wrote:

I don't have a LOT of experience with this, but am now running my electric dinghy with two separate 48V ebike batteries.

I like keeping them separate so that if one gets accidentally discharged (or any other failure), I still have a second battery to get home on.

On Wednesday, November 8, 2023 at 01:59:35 PM CST, Myles Twete <matwete@comcast.net> wrote:

Thought: Dangerous for the switch unless it's a break-before-make or other exclusive-or arrangement.

Why: You've been running for hours on one string, then decide to switch to the other. If you thought that you'd just use a standard marine battery combiner switch, you could accidentally switch to "ALL" position, which would then put both strings in parallel thru the switch, quickly shorting it and possibly melting the housing. Might also have a problem with that type of switch switching between each string.

With Lithium-Ion there's something to be said for having separate strings---ability to switch and get a higher pack voltage again for a time giving higher power/speed than if the strings were paralleled and slowly going down together. But really, a slowly dropping voltage is better than one that drops much faster due to not paralleling. Not as much of a big deal with LiFePo, but still, I'd tend to think paralleling is better.

Just a thought.
-MT

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of ChristopherH via groups.io
Sent: Wednesday, November 8, 2023 11:49 AM
To: electricboats@groups.io
Subject: Re: [electricboats] Parallel LiFePO4 Packs

Bobkart,
Thanks for the reply. Actually I'm proposing to have 2 independent 16 cell strings with the ability to parallel them at the 48V level with switches, not at the cell level. Thoughts on that?

Chris
Sent from myPhone

On Nov 8, 2023, at 14:40, bobkart <couch45@msn.com> wrote:

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

Re: [electricboats] Parallel LiFePO4 Packs

Good Article.

I would use one of these two approaches: either double each cell and build a single, double-capacity battery, with one BMS, etc.

Or, build two completely separate batteries, each with their own BMS, meters, etc.
And only run off of one battery at a time, never parallel them.

Upsides of the latter are the redundancy/failover you're interested it.
Downsides are that you're pulling at a higher C Rate, and most likely will use more Depth Of Discharge.
And of course the extra BMS/etc. overhead.

I've seen battery combiners for Ebike batteries that are basically a pair of diodes.
Eliminates any current flow between batteries while still allowing flow to the load from either battery.
Current levels for our use case are much higher than for Ebikes, so the diodes would need to be big, and probably expensive.
And they could get hot due to voltage drop, thus wasting energy. And are another potential point of failure.

https://www.electromotivemods.com/shop/p/s1fmuuaawo86hdw5gduhknspnoks37

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Re: [electricboats] Parallel LiFePO4 Packs

I found this great article by Orion BMS that discusses parallel strings. Reading this really makes me lean toward parallel cells as you wise gents previously suggested.

Thanks again for all the valuable input.

Chris

parallel_strings

PDF Document · 408 KB

Sent from myPhone

On Nov 8, 2023, at 16:58, ChristopherH via groups.io <clh5_98=yahoo.com@groups.io> wrote:

Reuben,
From what I've seen, Victron only have BMS for their line of packaged batteries in the 12 and 24 volt ranges.

Chris

Sent from myPhone

On Nov 8, 2023, at 16:55, Chris Hudson <clh5_98@yahoo.com> wrote:

John,
Thanks for your input and good point about having an ace in the hole!
Chris

Sent from myPhone

On Nov 8, 2023, at 16:22, john via groups.io <oak_box=yahoo.com@groups.io> wrote:

I don't have a LOT of experience with this, but am now running my electric dinghy with two separate 48V ebike batteries.

I like keeping them separate so that if one gets accidentally discharged (or any other failure), I still have a second battery to get home on.

On Wednesday, November 8, 2023 at 01:59:35 PM CST, Myles Twete <matwete@comcast.net> wrote:

Thought: Dangerous for the switch unless it's a break-before-make or other exclusive-or arrangement.

Why: You've been running for hours on one string, then decide to switch to the other. If you thought that you'd just use a standard marine battery combiner switch, you could accidentally switch to "ALL" position, which would then put both strings in parallel thru the switch, quickly shorting it and possibly melting the housing. Might also have a problem with that type of switch switching between each string.

With Lithium-Ion there's something to be said for having separate strings---ability to switch and get a higher pack voltage again for a time giving higher power/speed than if the strings were paralleled and slowly going down together. But really, a slowly dropping voltage is better than one that drops much faster due to not paralleling. Not as much of a big deal with LiFePo, but still, I'd tend to think paralleling is better.

Just a thought.
-MT

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of ChristopherH via groups.io
Sent: Wednesday, November 8, 2023 11:49 AM
To: electricboats@groups.io
Subject: Re: [electricboats] Parallel LiFePO4 Packs

Bobkart,
Thanks for the reply. Actually I'm proposing to have 2 independent 16 cell strings with the ability to parallel them at the 48V level with switches, not at the cell level. Thoughts on that?

Chris
Sent from myPhone

On Nov 8, 2023, at 14:40, bobkart <couch45@msn.com> wrote:

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

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

I don't think it happens that much. When I called Thunderstruck it took a fair amount of back and forth to figure it out and they said that they had never seen it fail before. This is my second year using the motor with no issues since.

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

That's it! Once you take the 3 screws off you'll see the board mounted underneath with a bunch of gunk holding it in place.

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Re: [electricboats] Parallel LiFePO4 Packs

Reuben,

From what I've seen, Victron only have BMS for their line of packaged batteries in the 12 and 24 volt ranges.

Chris

Sent from myPhone

On Nov 8, 2023, at 16:55, Chris Hudson <clh5_98@yahoo.com> wrote:

John,
Thanks for your input and good point about having an ace in the hole!
Chris

Sent from myPhone

On Nov 8, 2023, at 16:22, john via groups.io <oak_box=yahoo.com@groups.io> wrote:

I don't have a LOT of experience with this, but am now running my electric dinghy with two separate 48V ebike batteries.

I like keeping them separate so that if one gets accidentally discharged (or any other failure), I still have a second battery to get home on.

On Wednesday, November 8, 2023 at 01:59:35 PM CST, Myles Twete <matwete@comcast.net> wrote:

Thought: Dangerous for the switch unless it's a break-before-make or other exclusive-or arrangement.

Why: You've been running for hours on one string, then decide to switch to the other. If you thought that you'd just use a standard marine battery combiner switch, you could accidentally switch to "ALL" position, which would then put both strings in parallel thru the switch, quickly shorting it and possibly melting the housing. Might also have a problem with that type of switch switching between each string.

With Lithium-Ion there's something to be said for having separate strings---ability to switch and get a higher pack voltage again for a time giving higher power/speed than if the strings were paralleled and slowly going down together. But really, a slowly dropping voltage is better than one that drops much faster due to not paralleling. Not as much of a big deal with LiFePo, but still, I'd tend to think paralleling is better.

Just a thought.
-MT

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of ChristopherH via groups.io
Sent: Wednesday, November 8, 2023 11:49 AM
To: electricboats@groups.io
Subject: Re: [electricboats] Parallel LiFePO4 Packs

Bobkart,
Thanks for the reply. Actually I'm proposing to have 2 independent 16 cell strings with the ability to parallel them at the 48V level with switches, not at the cell level. Thoughts on that?

Chris
Sent from myPhone

On Nov 8, 2023, at 14:40, bobkart <couch45@msn.com> wrote:

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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