Cruisers Forum
 


Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 12-06-2019, 15:45   #76
Registered User

Join Date: Nov 2015
Boat: R&C Leopard 40
Posts: 635
Re: Switch from AGM to Lith-ion

Quote:
Originally Posted by tanglewood View Post
I agree. I find LFP to be much easier to manage on a day to day basis, because you can just ignore them. No worries about partial state of charge, no worries about when you last got to a full recharge, no worries about when you will next get to a full recharge, no worries about how sulfated your batteries are, no worries about when and how long to equalize, no worries about absorption time, no worries about shutting off the generator before full charge. None of that. Just ignore them


All the work is in setting things up, and it's no harder than tuning your chargers for AGMs. Set the max voltages, set the max absorb times, set the float voltage, and you are done. If something starts to run out of bounds, you will get a warning from your BMS. Note that "your BMS" could be an electronic device, or it could be you keeping an eye on things.


And unlike AGMs, if you try to run your batteries into the ground, the BMS will disconnect to protect the batteries from you. Your AGMs don't do that, and will happily let you ruin them. And if your LFP batteries are overcharging for whatever reason, your BMS will disconnect them to protect themselves and your boat from you. AGMs will happily let you cook them to a crisp.
Nothing is stopping someone from adding protections to their AGM banks. Except the cost/benefit ratio doesn't usually justify it, unlike Lithium where the bank is so costly and the risk so great that it usually does warrant built in protections and redundancies.
__________________
-Chris
FlyingScot is offline   Reply With Quote
Old 12-06-2019, 18:42   #77
Registered User

Join Date: Feb 2015
Posts: 955
Images: 1
Re: Switch from AGM to Lith-ion

Quote:
Originally Posted by FlyingScot View Post
Nothing is stopping someone from adding protections to their AGM banks. Except the cost/benefit ratio doesn't usually justify it, unlike Lithium where the bank is so costly and the risk so great that it usually does warrant built in protections and redundancies.

Agreed. But my point is that the day to day operation is, well, nothing. And the rare pathological cases of over charge and under charge are no more likely to occur with LFP than with LA. And because it's worth some protection, the risk of actual damage to the bank with LFP is way lower than LA.
__________________
www.MVTanglewood.com
tanglewood is offline   Reply With Quote
Old 13-06-2019, 01:30   #78
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Denmark (Winter), Helsinki (Summer); Cruising the Baltic Sea this year!
Boat: Cutter-Rigged Moody 54
Posts: 32,718
Re: Switch from AGM to Lith-ion

Quote:
Originally Posted by FlyingScot View Post
Nothing is stopping someone from adding protections to their AGM banks. Except the cost/benefit ratio doesn't usually justify it, unlike Lithium where the bank is so costly and the risk so great that it usually does warrant built in protections and redundancies.

I think if I were going to stay with lead batteries, I would add a BMS with HV and LV cutoffs just like for lithium. It just makes so much sense compared to going naked the way we do. That's one reason why lithium became much less intimidating, the more I learned about it -- BMS just makes sense -- you are preventing the same kind of accidents we have with lead batteries.



Why do people still think lithium is "so costly"? I don't think that's true any more at all. I think the cost of LiFePo4 cells is already comparable to premium AGM when measured by USABLE energy storage capacity, and when you factor in cycle life, it's much cheaper. In Europe, they cost about €1.10 per amp/hour at 3.2v; equivalent to €4.40 at 12v. So €440 for a 12v battery with usable capacity of about 90 amp/hours.


Compare with for example Trojan 12 AGMs -- €419 for 140 amp/hours -- so 70 amp/hours usable. Or Rolls Series 2 -- €219 for 100 amp/hours or 50 amp/hours usable.



It's a mistake to factor in the cost of the BMS and other elements of the installation -- first of all, these are not consumables. Second, their existence represents a significant improvement in functionality and reliability of the battery system, and once you know about them, you would want them with lead, too.
__________________
"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 offline   Reply With Quote
Old 13-06-2019, 01:56   #79
cruiser

Join Date: Jan 2012
Location: Pangaea
Posts: 10,856
Re: Switch from AGM to Lith-ion

Regarding cost

We just had one of our 8 year old Trojan T105 batteries go bad. The cost to replace it will be around $200, the rest of them are still going strong.

It doesn’t get any cheaper than this.
Kenomac is offline   Reply With Quote
Old 13-06-2019, 03:20   #80
Registered User

Join Date: Feb 2017
Location: Panama, Central America
Boat: CT 49, 1989
Posts: 908
Re: Switch from AGM to Lith-ion

Quote:
Originally Posted by FlyingScot View Post
Nothing is stopping someone from adding protections to their AGM banks. Except the cost/benefit ratio doesn't usually justify it, unlike Lithium where the bank is so costly and the risk so great that it usually does warrant built in protections and redundancies.
Thats exactly what I have done. Put LVC and HVC's on my old FLA's. Admittedly this is mostly in preparation for LFP's. Still hashing around which LFPs I will get.

I previously had a 'mishap' with one of my solar charge convertor connection. Causing my batteries to not get charged and discharge themselves to death. FLAs are not the expence of LFPs but still not insignificant. Apart from the hassle of having to get and fit new ones. I still reckon LVC is still worth it even for humble FLA banks, IMHO.
Q Xopa is offline   Reply With Quote
Old 09-08-2019, 02:33   #81
Registered User
 
Skip JayR's Avatar

Join Date: Jul 2015
Location: see https://trienthusiasts.wordpress.com/
Boat: still looking for the right Tri
Posts: 482
Re: Switch from AGM to Lith-ion

Just like to share an article I just read about latest research of Lithium-Ion batteries and alternative materials, e.g. Sodium. Sounds promising for me.

https://oilprice.com/Energy/Energy-G...Batteries.html
Skip JayR is offline   Reply With Quote
Old 09-08-2019, 03:49   #82
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Denmark (Winter), Helsinki (Summer); Cruising the Baltic Sea this year!
Boat: Cutter-Rigged Moody 54
Posts: 32,718
Re: Switch from AGM to Lith-ion

Quote:
Originally Posted by Q Xopa View Post
Thats exactly what I have done. Put LVC and HVC's on my old FLA's. Admittedly this is mostly in preparation for LFP's. Still hashing around which LFPs I will get.

I previously had a 'mishap' with one of my solar charge convertor connection. Causing my batteries to not get charged and discharge themselves to death. FLAs are not the expence of LFPs but still not insignificant. Apart from the hassle of having to get and fit new ones. I still reckon LVC is still worth it even for humble FLA banks, IMHO.

Totally agree with this


It's funny we've developed all this stuff for lithium but that doesn't mean it is not relevant for lead. If for some reason I were to continue using lead I would definitely implement some kind of simple BMS with HVC and LVC. It just makes so much sense. All the lead batteries I've killed in the last 10 years ( . . . if I had a dollar for every time . . . ) without exception would have been saved by a simple BMS.



To implement HVC and LVC for a lead bank would be totally simple -- Victron battery monitor, relay, couple of contactors. Temperature monitor with another relay to disconnect the charger. Bob turns into an uncle.
__________________
"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 offline   Reply With Quote
Reply

Tags
agm

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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
Smart Battery (lith) nnb4oc Electrical: Batteries, Generators & Solar 3 22-11-2017 10:59
2 AGM 31s to the battery switch -best way? LeeV Electrical: Batteries, Generators & Solar 5 29-04-2016 08:51
Lithium Ion Breakthrough - forgetful-scientists-accidentally-quadruple-lithium-ion-ba zboss Electrical: Batteries, Generators & Solar 8 22-08-2015 23:35
Switch from AGM to FLA batteries Utahsailor Electrical: Batteries, Generators & Solar 8 03-04-2015 08:03

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 - 2022, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2022, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.