|
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.?
toggle quoted message
Show quoted text
On Nov 9, 2023, at 11:16, Stew <stewart.reed@...> 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.
|
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/
|
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 ?
?
|
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.
toggle quoted message
Show quoted text
On Nov 20, 2023, at 16:41, Reuben Trane via groups.io <rjtrane@...> 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 ?
?
|
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
ABYC Certified Marine? Electrical Technician?
On Monday, November 20, 2023 at 12:32:01 PM EST, Kel Bryant <kelbryant@...> 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/
|
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
?
|
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
? ?
|
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]
|
Check your math? 1,000AH/48v is 50kWh. I get about 25NM at 5 knots.?
|
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
-- Jeff LaCoursiere s/v Angels Quest St Thomas USVI
|
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]
|
?
12m - over 20,000# - has 5kW solar - 2 each 10kW Motenergy water-cooled motors ?
|
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@...> 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]
|
Great advice. My 30kwh pack batteries (lithium ion, 20P(1.5kwh, 42vnom)) are only connected to a charging system after reaching somewhere between 33 and 36v, and then only charging overnight to 48v (max. batt spec is 49.1v).? I manually disconnect the next day.? Going further, I do not totally trust BMS cards (and for good reason) and so I only power them up maybe once every 6-18months to check cell balance across the 240 cell pairs.? Even with that, I have heard from at least one European owner of THINK cars with these batteries/BMS indicate to me that he has seen even unpowered BMS cards drain a cell pair. ?So there’s that risk also.? Further on the non-trusting side, the software I wrote to communicate with 20 BMS cards and manage all the balancing only enables balancing on one of the 20 module strings at a time---only the worst one.? This has the advantages of minimizing the number of bypass circuits that are enabled and lowering the risk that they will degrade quicker or worse, that one of them might get stuck ON.? Since all the modules are in parallel, as a string is bypass balancing, the other parallel strings will supply that string with current, maintaining the string voltage and only slowly dropping the pack voltage---far better than bypassing ALL the high cells in the pack to bring them all down to the low voltage.? Works like a charm. ? Anyway, stay safe. ? -MT ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Harley Clark
Sent: Wednesday, November 22, 2023 5:22 PM
To: [email protected]
Subject: 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@...> 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]
|
Reuben Trane
THOMAS VANDERMEULEN