Reply
 
Thread Tools Search this Thread Display Modes
 
Old 01-16-2021, 12:48 PM   #1
Veteran Member
 
Flyguy1967's Avatar
 
City: PNW
Vessel Model: 1984 Ponderosa 48 CPMY
Join Date: Aug 2009
Posts: 93
Special Considerations for Charging LiFePO Batteries

Braintrust,

I am replacing my house bank (24v) to LiFePO. The bank charges from both a dedicated battery charger and the alternator from the port engine. What have those of you who have switched to LiFePO done to modify your charging system (alternator and battery charger)?

Thanks in advance for your input!
__________________
Advertisement

Flyguy1967 is offline   Reply With Quote
Old 01-16-2021, 03:02 PM   #2
Guru
 
Xsbank's Avatar
 
City: Pender Harbour, BC
Vessel Name: Gwaii Haanas
Vessel Model: Custom Aluminum 52
Join Date: Sep 2013
Posts: 3,770
Never mind.
__________________

__________________
Don't believe everything that you think.
Xsbank is offline   Reply With Quote
Old 01-16-2021, 03:28 PM   #3
Guru
 
Comodave's Avatar
 
City: Au Gres, MI
Vessel Name: Never Say Never
Vessel Model: President 41 DC
Join Date: Jul 2015
Posts: 10,733
I am doing that right now. I have a 120 amp Balmar alternator that will just charge the house bank. I have a 60 amp Promariner that will be dedicated to the lithium house bank. Sounds pretty much like your setup. .
__________________
Boat Nut:
If you are one there is no explanation necessary.
If you arenít one, there is no explanation possible.
Comodave is offline   Reply With Quote
Old 01-16-2021, 03:57 PM   #4
Valued Technical Contributor
 
DavidM's Avatar
 
City: Litchfield, Ct
Join Date: Aug 2012
Posts: 5,723
For best results LFP batteries need a charger that peaks at 14.4-14.6 for best results. If you use a conventional three step charger it will usually peak out at a lower voltage which won't charge the last 10% or so, but otherwise works ok.

So for best results you need an alternator/regulator and a shore power charger that can be set for these parameters.

If your alternator has an external regulator usually a Balmar you can switch it out with their new one with standard LFP parameters or set up an older one yourself for these parameters and do the same with your shore power charger. But like I say all of this changeout only affects the last 10% of LFP charging.

David
DavidM is online now   Reply With Quote
Old 01-17-2021, 12:43 AM   #5
Veteran Member
 
Flyguy1967's Avatar
 
City: PNW
Vessel Model: 1984 Ponderosa 48 CPMY
Join Date: Aug 2009
Posts: 93
Thanks for the feedback!

The internet is a dangerous place but read that there may be an issue of overheating the alternator and David confirmed that conventional chargers pump only 13.xx into the bank.

ComoDave - I bought the same batteries from Costco that you purchased (Lion Energy). Cannot believe how light those batteries are!

After I started this thread, came across this from Victron:

https://www.victronenergy.com/blog/2...rging-lithium/

I guess there may be some more bits to purchase and install.
Flyguy1967 is offline   Reply With Quote
Old 01-17-2021, 02:20 AM   #6
Guru
 
Comodave's Avatar
 
City: Au Gres, MI
Vessel Name: Never Say Never
Vessel Model: President 41 DC
Join Date: Jul 2015
Posts: 10,733
I love that the terminals come off so I could use bus bars instead of cables.
__________________
Boat Nut:
If you are one there is no explanation necessary.
If you arenít one, there is no explanation possible.
Comodave is offline   Reply With Quote
Old 01-17-2021, 02:22 AM   #7
Guru
 
Comodave's Avatar
 
City: Au Gres, MI
Vessel Name: Never Say Never
Vessel Model: President 41 DC
Join Date: Jul 2015
Posts: 10,733
I asked Balmar about the BMS turning the batteries off and damaging the alternator. They told me to use an alternator protection device. I got one from Compass Marine and will be installing it when I put the engine back in.
__________________
Boat Nut:
If you are one there is no explanation necessary.
If you arenít one, there is no explanation possible.
Comodave is offline   Reply With Quote
Old 01-17-2021, 07:38 AM   #8
Valued Technical Contributor
 
DavidM's Avatar
 
City: Litchfield, Ct
Join Date: Aug 2012
Posts: 5,723
There are two alternator protection issues mentioned above when using LFP batteries:

Comodave noted above that the BMS will shut off the battery and potentially damage the alternator. This isn't like turning the 1,2,all, off switch to off. You still have the house loads connected to absorb the alternator output. The only way the BMS might be an issue is if you were charging the house bank and there was no load connected. But that diode is always good to have in place.

The other issue is overloading the alternator since LFP batteries can pull a lot of current. Use Balmar's alternator temp probe which will cut output in half if it gets too hot.

David
DavidM is online now   Reply With Quote
Old 01-19-2021, 01:05 PM   #9
Senior Member
 
City: San Diego, CA
Vessel Model: 42' Uniflite Double Cabin
Join Date: Jul 2017
Posts: 471
Your batteries should have the specifications for what the charge profile needs to be. If your existing alternator/charge devices can't be set to those specifications, they should be replaced or modified to do so. For the alternator, an external regulator that can sense alternator temperature and reduce output if the alternator gets hot is useful.

The alternator protection device by Sterling Power is designed to absorb an alternator created voltage spike if the internal BMS on your batteries decides to disconnect suddenly. Not sure if that same device has any useful effect on solar charge controllers that might be pumping a lot of amps in during a disconnect event.
__________________

sbman is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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



» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 10:37 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012
×