Cruisers Forum
 


Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 13-09-2018, 08:29   #166
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Denmark (Winter), Cruising North Sea and Baltic (Summer)
Boat: Cutter-Rigged Moody 54
Posts: 34,567
Re: LFP FLA hybrid

Quote:
Originally Posted by Qayaq View Post
Really, 80 amp windlass use 2 minutes = 2.6amps... I think.. Its not constant ,think you are going to find your fridge is going to use more in a day than your windlass

Was this addressed to me?


Besides the windlass, I have a 10 horsepower bow thruster on my technical bank, which does use a bit of power, but you are right that all these loads are used only for short periods of time.


The banks were separated by the designer not to divide up the consumption, but to prevent voltage sags from using the very large technical consumers from taking down the electronics.



But that was in 2001, when my boat was made -- the next generation of electronics already didn't care about such voltage sags, and so in 2010 I combined the two banks so that all the power of both banks could support the house loads.



The problem with that is that the two battery boxes are 10 meters away from each other, which makes it impossible to balance the batteries well. One reason I consider going to lithium (or hybrid) is to solve this problem. Lithium would be fabulous for the bow thruster -- I calculate I will get a 25% boost in horsepower, and the thruster will run cooler. Because of almost no Peukert, these large loads will also use up battery capacity less.
__________________
"You sea! I resign myself to you also . . . . I guess what you mean,
I behold from the beach your crooked inviting fingers,
I believe you refuse to go back without feeling of me;
We must have a turn together . . . . I undress . . . . hurry me out of sight of the land,
Cushion me soft . . . . rock me in billowy drowse,
Dash me with amorous wet . . . . I can repay you."
Walt Whitman
Dockhead is online now   Reply With Quote
Old 13-09-2018, 08:54   #167
cruiser

Join Date: Jan 2017
Boat: Retired from CF
Posts: 13,317
Re: LFP FLA hybrid

Quote:
Originally Posted by Dockhead View Post
What do you do if you want to stop charging the lithium but you want the alternator online to power ongoing loads?

This is not a problem with a hybrid bank where the alternator is connected to the lead. But how about the other way around? I hadn't thought of this issue, but it must be a basic question for lithium only banks. What is the answer? Is there a voltage at which the alternator can be regulated to, which will allow it to take loads without putting charge into the lithium?
you could float at 3.3Vpc, but I would not do that for long.

A $20 sacrificial lead batt is simplest way otherwise if you don't have a starter to divert to.


> Sure, but I think by convention we are referring to HVC as the high voltage cutoff in the BMS. Whatever functionality in the control system external to the BMS probably should be referred to in a different way, no?

Well some here don't like my convention of only including "last layer failsafe" as "BMS" functionality, prefer to call all the control systems with that label.

So I figure best to spell out specifically.


> And how do mains chargers with a lithium profile work? How do they handle loads AND a full lithium bank?

Forget anything labeled "for lithium", V is always too high.

Just need adjustability.

And that functionality is not built in, up to you as the DIY / installer / designer to figure out what works for your setup.

Or pay someone like Bruce for extra consulting if you're buying a packaged system.

> Sterling Alternator Lineariser

Will investigate.
john61ct is offline   Reply With Quote
Old 13-09-2018, 08:57   #168
cruiser

Join Date: Jan 2017
Boat: Retired from CF
Posts: 13,317
Re: LFP FLA hybrid

> >My point with the above is that the LFP bank's charging can be terminated when it hits the target voltage, while the lead & loads continue to receive current, going to the higher V the lead requires, and all from the same charge source.

_____
> Well, sure -- that's the easy solution already mentioned. But what do you do if you can't do it that way?

Well like you say, duplicate all charge sources?

But I'm sure we can come up with better.

Why "can't" though?
john61ct is offline   Reply With Quote
Old 13-09-2018, 09:05   #169
cruiser

Join Date: Jan 2017
Boat: Retired from CF
Posts: 13,317
Re: LFP FLA hybrid

To keep this thread useful

could members refrain from any discussion along the lines of "you don't need LFP".

Assume LFP is a given here, focus of the thread is **how** to implement.

Ideally the FLA+LFP hybrid concept specifically.

Otherwise the thread gets bogged down with tangents and side discussions, much less useful.

Start a new thread for those, and a short link between threads does not interfere with the main flow.

If you support this idea, please just ignore the OT members, or answer them with a link to another thread for that purpose.

New threads are Free!
john61ct is offline   Reply With Quote
Old 13-09-2018, 09:05   #170
Marine Service Provider

Join Date: May 2011
Location: Cruising Mexico Currently
Boat: Gulfstar 50
Posts: 1,980
Re: LFP FLA hybrid

In this and other threads I keep coming to the conclusion that we are trying to do 2 things with a BMS.

The first is the monitoring, warning and disconnect functions. In other words a protection function.

The other is a control (specifically of charging sources) function.

I cannot but think that a separate charge controller would be useful. Especially one with a full range of features.

Of course a high end BMS "should" do these kinds of things.





N.B. My only direct experience with BMS are with the HousePower BMS.
evm1024 is offline   Reply With Quote
Old 13-09-2018, 09:09   #171
cruiser

Join Date: Jan 2017
Boat: Retired from CF
Posts: 13,317
Re: LFP FLA hybrid

Yes let's keep so-called drop-ins out of serious LFP discussions.
john61ct is offline   Reply With Quote
Old 13-09-2018, 09:11   #172
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Denmark (Winter), Cruising North Sea and Baltic (Summer)
Boat: Cutter-Rigged Moody 54
Posts: 34,567
Re: LFP FLA hybrid

Quote:
Originally Posted by john61ct View Post
> My point with the above is that the LFP bank's charging can be terminated when it hits the target voltage, while the lead & loads continue to receive current, going to the higher V the lead requires, and all from the same charge source.

_____
Well, sure -- that's the easy solution already mentioned. But what do you do if you can't do it that way?

Well like you say, duplicate all charge sources?

But I'm sure we can come up with better.

Why "can't" though?

Yes, I understood that a while back.




I COULD connect alternator to lead, but then I have to have a second B2B charger with complicated method of switching it around, to charge the lithium. Not elegant.


But Charles' Alternator Lineariser completely solves this problem I think --


You connect the alternator via the Lineariser to a charging bus, which is connected to the lithium via a contactor, and is also connected to the B2B charger.


Et voila.


When the lithium is full, you simply disconnect it. And the alternator carries on powering the house loads and charging the lead via the B2B charger.


I bet that's one of the main purposes of that device.



Only one tiny problem with that --


I would sure like the alternator to be connected to the lithium bank, even when it's full, when I'm using heavy technical loads like the bow thruster.


Perhaps the very small voltage drop will be enough to cause the control system to call for connection to the alternator.
__________________
"You sea! I resign myself to you also . . . . I guess what you mean,
I behold from the beach your crooked inviting fingers,
I believe you refuse to go back without feeling of me;
We must have a turn together . . . . I undress . . . . hurry me out of sight of the land,
Cushion me soft . . . . rock me in billowy drowse,
Dash me with amorous wet . . . . I can repay you."
Walt Whitman
Dockhead is online now   Reply With Quote
Old 13-09-2018, 09:17   #173
Registered User

Join Date: Nov 2014
Location: Germany
Boat: Beneteau Sense 43
Posts: 176
Re: LFP FLA hybrid

Quote:
Originally Posted by Dockhead View Post
Only one tiny problem with that --

I would sure like the alternator to be connected to the lithium bank, even when it's full, when I'm using heavy technical loads like the bow thruster.

Perhaps the very small voltage drop will be enough to cause the control system to call for connection to the alternator.
I'd probably not worry too much about that. The LFP bank will happily drive your bow thruster. Quick calculation: I remember you mentioned 10 HP (~ 7.5 kW) - this would be a bit less than 600 A at 13 V. Piece of cake for a LFP bank of at least 200 Ah (3C) for a short time.

How much would your alternator contribute? 100 A? Does not change much.

Remember, get rid of the Lead Acid mindset. LFPs are fine with high loads.
mbartosch is offline   Reply With Quote
Old 13-09-2018, 09:18   #174
cruiser

Join Date: Jan 2017
Boat: Retired from CF
Posts: 13,317
Re: LFP FLA hybrid

Quote:
Originally Posted by Dockhead View Post
But Charles' Alternator Lineariser completely solves this problem I think
Why not start a new thread?

#1 introduce the new Sterling gadget, link to the docs and explain its purpose how it works.

Charles sometimes creates Solutions in search of an actual Problem.

This will force you to really figure it out, "if you want to learn teach".

Once it seems we all are au fait with it, after any relevant discussion / debate has settled down (hopefully ignoring any trolls that may appear)

then #2 let's break down how it may fit into your use case, up to you in that thread or (IMO best to) link to a new one
john61ct is offline   Reply With Quote
Old 13-09-2018, 09:23   #175
cruiser

Join Date: Jan 2017
Boat: Retired from CF
Posts: 13,317
Re: LFP FLA hybrid

Quote:
Originally Posted by mbartosch View Post
How much would your alternator contribute? 100 A? Does not change much.

Remember, get rid of the Lead Acid mindset. LFPs are fine with high loads.
And if voltage / SoC does drop, the contact should open to receive the current from the Alt anyway.
john61ct is offline   Reply With Quote
Old 13-09-2018, 10:41   #176
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Denmark (Winter), Cruising North Sea and Baltic (Summer)
Boat: Cutter-Rigged Moody 54
Posts: 34,567
Re: LFP FLA hybrid

Quote:
Originally Posted by mbartosch View Post
I'd probably not worry too much about that. The LFP bank will happily drive your bow thruster. Quick calculation: I remember you mentioned 10 HP (~ 7.5 kW) - this would be a bit less than 600 A at 13 V. Piece of cake for a LFP bank of at least 200 Ah (3C) for a short time.

How much would your alternator contribute? 100 A? Does not change much.

Remember, get rid of the Lead Acid mindset. LFPs are fine with high loads.

You could very well be right.


Yes, the thruster needs up to 350 amps at 24v (and momentarily more than that). The technical bank would be 200 amp/hours to 260 amp/hours (depending on whether or not there's lead in the other bank). That's going to be less than 2C which I believe is not a problem.



The alternator produces up to 110 amps @ 24v which takes a decent bite out of the load, but I suppose it really doesn't matter that much, does it? The actual power consumed is not that much and will be replaced.
__________________
"You sea! I resign myself to you also . . . . I guess what you mean,
I behold from the beach your crooked inviting fingers,
I believe you refuse to go back without feeling of me;
We must have a turn together . . . . I undress . . . . hurry me out of sight of the land,
Cushion me soft . . . . rock me in billowy drowse,
Dash me with amorous wet . . . . I can repay you."
Walt Whitman
Dockhead is online now   Reply With Quote
Old 13-09-2018, 10:42   #177
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Denmark (Winter), Cruising North Sea and Baltic (Summer)
Boat: Cutter-Rigged Moody 54
Posts: 34,567
Re: LFP FLA hybrid

Quote:
Originally Posted by john61ct View Post
And if voltage / SoC does drop, the contact should open to receive the current from the Alt anyway.

Yes, I got that. Thanks.
__________________
"You sea! I resign myself to you also . . . . I guess what you mean,
I behold from the beach your crooked inviting fingers,
I believe you refuse to go back without feeling of me;
We must have a turn together . . . . I undress . . . . hurry me out of sight of the land,
Cushion me soft . . . . rock me in billowy drowse,
Dash me with amorous wet . . . . I can repay you."
Walt Whitman
Dockhead is online now   Reply With Quote
Old 13-09-2018, 10:47   #178
cruiser

Join Date: Jan 2012
Location: Lake Ontario
Boat: Ontario 38 / Douglas 32 Mk II
Posts: 3,250
Re: LFP FLA hybrid

Quote:
Originally Posted by john61ct View Post
To keep this thread useful

could members refrain from any discussion along the lines of "you don't need LFP".

Assume LFP is a given here, focus of the thread is **how** to implement.

Ideally the FLA+LFP hybrid concept specifically.

Otherwise the thread gets bogged down with tangents and side discussions, much less useful.

Start a new thread for those, and a short link between threads does not interfere with the main flow.

If you support this idea, please just ignore the OT members, or answer them with a link to another thread for that purpose.

New threads are Free!
John, if you are referring to post 160 and 165, I believe these are valid questions, and more relevant to the original post, than most.

If you disagree, please feel free to disregard any responses or ensuing discussion.

You have absolutely no authority to dictate what others post in a thread.
ramblinrod is offline   Reply With Quote
Old 13-09-2018, 10:59   #179
Registered User

Join Date: Feb 2015
Posts: 1,242
Images: 1
Re: LFP FLA hybrid

Quote:
Originally Posted by Dockhead

I would sure like the alternator to be connected to the lithium bank, even when it's full, when I'm using heavy technical loads like the bow Thruster.


I see this as one of the big downsides to swapping in an LA battery when the LFP is full. You now have limited power for thrusters, large inverter loads, and inverter features like power assist from batteries when on shore or generator.
__________________
www.MVTanglewood.com
tanglewood is offline   Reply With Quote
Old 13-09-2018, 11:05   #180
Registered User

Join Date: Nov 2014
Location: Germany
Boat: Beneteau Sense 43
Posts: 176
Re: LFP FLA hybrid

Quote:
Originally Posted by Dockhead View Post
Yes, the thruster needs up to 350 amps at 24v (and momentarily more than that). The technical bank would be 200 amp/hours to 260 amp/hours (depending on whether or not there's lead in the other bank). That's going to be less than 2C which I believe is not a problem.
Yes, this will be a piece of cake for the bank. (E. g. Winston cells are rated for continuous 3C, at 2C you could bowthruster your boat in small circles for half an hour nonstop without them breaking a sweat.)

Quote:
The alternator produces up to 110 amps @ 24v which takes a decent bite out of the load, but I suppose it really doesn't matter that much, does it? The actual power consumed is not that much and will be replaced.
Absolutely.

BTW, we'll be installing a 12 V/4.3 kW bow thruster on our boat this winter as well. It will be driven directly from the LFP house bank, no additional battery for this, of course.
In our case this means running a long cable, but my calculations indicate that this will be OK with regard to voltage drop/cable losses and of course current density in the cable.
mbartosch is offline   Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
LFP system design approach - comments welcome tanglewood Electrical: Batteries, Generators & Solar 18 06-06-2018 11:35
US source for CALB CA180 LFP batteries? tanglewood Electrical: Batteries, Generators & Solar 23 04-06-2018 17:08
[B]Best practice charging for LFP & LFMP bank?[/B] BigBeakie Electrical: Batteries, Generators & Solar 71 16-12-2017 14:42
LFP Cell or BMS Failure CharlieJ Electrical: Batteries, Generators & Solar 21 15-09-2016 19:48
East Coast of Fla to West Coast Fla ub1 Navigation 6 24-08-2013 18:33

Advertise Here


All times are GMT -7. The time now is 13:48.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.