Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 10-06-2018, 12:54   #16
Registered User

Join Date: Jan 2017
Posts: 4,575
Re: AC battery charger for AGM start battery and Lithium bank

Best practice IMO is to use a properly sized fully adjustable DC-DC B2B charger to care for your more sensitive bank chemistry.

That will then precisely filter / massage whatever random stock charge sources you care to put on your less fussy more robust lead bank.

Sterling keeps saying 180 - 250+ amp units coming real soon now, but the 120A models can be stacked if needed.

Using diodes etc to adjust voltage is imprecise at best, output varies with current level.
__________________

john61ct is offline   Reply With Quote
Old 10-06-2018, 14:25   #17
Registered User

Join Date: Nov 2014
Location: Germany
Boat: Beneteau Sense 43
Posts: 71
Re: AC battery charger for AGM start battery and Lithium bank

Hi Joe, good to hear you have finished your LiFePO4 project!
As others have said on this thread it is probably the best to add an inexpensive charger for the starter battery instead of searching for a device which can handle two different chemistries (I doubt such a thing exists...)

In the setup on our boat I am using a Victron Multiplus for charging the LiFePO4 bank from shore power (and providing AC power to the boat via the inverter). The Multiplus can be customized and programmed via a programming adapter and the Victron software. It really works well.

The starter battery has two chargers: a Sterling Battery to Battery charger which is fed from the LiFePO4 bank and uses the standard Lead Acid charging profile. I am using a 1 h timer relay to enable the B2B charger. The timer relay is triggered by the ignition switch and keeps the B2B charger running for 1 hour after the ignition is switched off. (In addition to this the starter battery BMV 700 battery monitor has been programmed to close its relay when the starter battery voltage drops below a certain threshold, also triggering the timer relay enabling the B2B charger).

In this setup the starter battery is only charged when the LiFePO4 bank is online. For prolonged stays at the dock I added an inexpensive Victron Blue Power IP 65 charger (15 A version). This charger is directly fed from shore power and attached to the starter battery, hence totally independent from the rest of the system. It is not programmable (only has three pre-programmed charging profiles), but that's sufficient for the starter battery.

This really works well and I like the solution.
__________________

mbartosch is offline   Reply With Quote
Old 10-06-2018, 14:27   #18
Registered User
 
CatNewBee's Avatar

Join Date: Aug 2017
Boat: Lagoon 400S2
Posts: 747
Re: AC battery charger for AGM start battery and Lithium bank

Quote:
Originally Posted by john61ct View Post
Best practice IMO is to use a properly sized fully adjustable DC-DC B2B charger to care for your more sensitive bank chemistry.

That will then precisely filter / massage whatever random stock charge sources you care to put on your less fussy more robust lead bank.

Sterling keeps saying 180 - 250+ amp units coming real soon now, but the 120A models can be stacked if needed.

Using diodes etc to adjust voltage is imprecise at best, output varies with current level.
well diodes in conjunction with a thermistor are solutions for keep a start battery topped up at float as second output in small / cheap controller up to 30A for the main output and 1..3A for float the starter.

the alternative is a battery combiner for two batteries, where you drop off the LFP at a lower voltage (e.g at 14V) while allowing the AGM to finish tha algorhythm alone up to 14.6..14.8V absorption and then float 13.8V, the LFP stays disconnected until the lower limit is hit (either SOC or a set voltage). Its an easy way to use any charger for LFP with a programmed cut-off, while the LA batteries enjoy a full charge cycle.
CatNewBee is offline   Reply With Quote
Old 10-06-2018, 18:50   #19
Registered User

Join Date: Jan 2017
Posts: 4,575
Re: AC battery charger for AGM start battery and Lithium bank

Again B2B is the way to go.

Although for going from LFP to a starter overkill expensive, I'd just use an Echo Charger.
john61ct is offline   Reply With Quote
Old 11-06-2018, 07:22   #20
Senior Cruiser

Cruisers Forum Supporter

Join Date: Mar 2014
Location: Anacortes
Boat: previous - Whitby 42 new - Goldenwave 44
Posts: 1,801
Re: AC battery charger for AGM start battery and Lithium bank

Quote:
Originally Posted by john61ct View Post
Maybe something's wrong with your browser.

A 10-sec google brought me straight to a 75 pg PDF of the full manual

Lots more available here https://www.victronenergy.com/chargers/skylla-ip44

than I ever saw offered by any of their competitors.

Pre purchase tech support available by email, actually competent engineers very responsive to intelligent discussions.

Please don't slag off such a world class CS-oriented outfit without at least putting in a minimal effort.

I did put in more than minimal effort but must have goofed. I downloaded it. Thanks
exMaggieDrum is offline   Reply With Quote
Old 11-06-2018, 07:44   #21
Senior Cruiser

Cruisers Forum Supporter

Join Date: Mar 2014
Location: Anacortes
Boat: previous - Whitby 42 new - Goldenwave 44
Posts: 1,801
Re: AC battery charger for AGM start battery and Lithium bank

Thanks for all the input, especially the corrections....


I do want a shorepower backup to my old Trace inverter/charger, for charging, so was thinking of a larger charger than just a minimal for the start battery. I hope that my solar will provide more than enough but lower latitudes don't help in that regard. A B2B solution will not provide a backup which is why I am not considering that. I do have the Echo Charger installed and it works well as a trickle charger. Although I have considered just a small charger, such as Barton has suggested, for the simplicity for charging the starter battery and cost. I may still do that.



My alternator will not be hooked up direct to the start battery although I can parallel it in if need be. What I am looking at is if the Li battery goes off so I don't want to be dependent on it being online to use or charge the start battery.



I also want to keep things simple as possible and don't want to add more complexity if I can help it. I am even considering not installing a BMS and manage the Li bank manually. There is some risk to this but I will be living aboard and so far it has worked fine. The times I would like it most is if I have to leave the boat for any extended time. I will probably put it in anyway but there are those out there very happy and successful without them. I have more questions about that but not for this thread.


I misspoke about Victron being German. I think I must have seen an ad from a German dealer and am going to fast to keep my brain in sync it seems. The Dutch are extraordinary engineers as well, although the prices for everything from there is as high as those from Germany. But the gear tends to be worth it if you need it.



Thank you for your comments. I have too much going on at the moment and not keeping all my ducks in as straight a line as I would like.
exMaggieDrum is offline   Reply With Quote
Old 11-06-2018, 10:20   #22
Registered User

Join Date: Jan 2017
Posts: 4,575
Re: AC battery charger for AGM start battery and Lithium bank

No worries, all good.

My reco in #4 stands, IMO the setpoints for any charger that might be used for LFP should be fully adjustable.

Being able to pump lots of amps, but also de-rate for weaker upstream sources is also great.
john61ct is offline   Reply With Quote
Old 12-06-2018, 09:30   #23
Senior Cruiser

Cruisers Forum Supporter

Join Date: Mar 2014
Location: Anacortes
Boat: previous - Whitby 42 new - Goldenwave 44
Posts: 1,801
Re: AC battery charger for AGM start battery and Lithium bank

Quote:
Originally Posted by john61ct View Post
No worries, all good.

My reco in #4 stands, IMO the setpoints for any charger that might be used for LFP should be fully adjustable.

Being able to pump lots of amps, but also de-rate for weaker upstream sources is also great.

I totally agree.
exMaggieDrum is offline   Reply With Quote
Old 12-06-2018, 10:55   #24
Marine Service Provider
 
Maine Sail's Avatar

Join Date: Jan 2007
Location: Maine
Boat: CS-36T - Cupecoy
Posts: 3,132
Re: AC battery charger for AGM start battery and Lithium bank

Quote:
Originally Posted by exMaggieDrum View Post
Pronautic was at the top of my list but I wanted to see if there has been any new developments, especially as demand for charging lithium batteries is rising. MaineSail seems to really like the Pronautic too.

I do like these chargers I just do not like the ProNautic or ProCharge Ultra for LFP. There is no adjustment to the absorption duration, just voltage. Remember it's not just about adjusting voltages it's about adjusting duration at constant voltage. With LFP the ideal charge is charge to XX.XX volts then STOP...


On a group I am in just this morning another ruined LFP bank showed up, a 700Ah Winston pack overcharged to death and extracted from the boat apparently smoking and blown up like a balloon. Not the first not the last.


Quote:
Originally Posted by exMaggieDrum View Post
I found a 60A model on sale online and will get that unless I get some more info here in the next few days about other tech out now.
Again, would not be my first choice for LFP unless you are 100% manually managing it yourself. The algorithm is designed for lead acid where the longer it remains in bulk the longer the absorption cycle is, absolutely backwards for charging LFP. With LFP we don't want any absorption or no more than a max of about 30 minutes, depending upon target voltage..

Beyond that you could grab one at MarineHowTo.com and support the site rather than some random shop who does not support the community...

Also, IMHO the Echo is a poor choice as it will be a continual bleed on your LFP bank as it simply turns on at 13V and you'll rarely if ever dip low enough for it to ever turn off. You could put a switch in the house bank line or the negative and manually excite it but, a Sterling BB1230 Battery to Battery Charger is a far superior piece of equipment and it can be ignition key excited rather than voltage excited, does buck or boost, has its own actual smart charge profile, has a temp sensor etc..
__________________
Marine How To Articles
Maine Sail is offline   Reply With Quote
Old 12-06-2018, 12:11   #25
Registered User
 
CatNewBee's Avatar

Join Date: Aug 2017
Boat: Lagoon 400S2
Posts: 747
Re: AC battery charger for AGM start battery and Lithium bank

Quote:
Originally Posted by Maine Sail View Post
I do like these chargers I just do not like the ProNautic or ProCharge Ultra for LFP. There is no adjustment to the absorption duration, just voltage. Remember it's not just about adjusting voltages it's about adjusting duration at constant voltage. With LFP the ideal charge is charge to XX.XX volts then STOP...


On a group I am in just this morning another ruined LFP bank showed up, a 700Ah Winston pack overcharged to death and extracted from the boat apparently smoking and blown up like a balloon. Not the first not the last.




Again, would not be my first choice for LFP unless you are 100% manually managing it yourself. The algorithm is designed for lead acid where the longer it remains in bulk the longer the absorption cycle is, absolutely backwards for charging LFP. With LFP we don't want any absorption or no more than a max of about 30 minutes, depending upon target voltage..

Beyond that you could grab one at MarineHowTo.com and support the site rather than some random shop who does not support the community...

Also, IMHO the Echo is a poor choice as it will be a continual bleed on your LFP bank as it simply turns on at 13V and you'll rarely if ever dip low enough for it to ever turn off. You could put a switch in the house bank line or the negative and manually excite it but, a Sterling BB1230 Battery to Battery Charger is a far superior piece of equipment and it can be ignition key excited rather than voltage excited, does buck or boost, has its own actual smart charge profile, has a temp sensor etc..
Hi Maine Sail,

I wonder why the BMS has not kicked in to stop overcharging the Winston battery and why there was no thermal alarm, what BMS was used, that caused the mess?

Probably another guy, that thinks BMS are for douches, he can monitor and manage his LFP better manualy. Probably also no automatic balancing, so one cell runs off..

I guess too many believe the fairy tales of charging manualy, not using a bms nor balancers to prolongue the life time of a battery.
CatNewBee is offline   Reply With Quote
Old 12-06-2018, 12:16   #26
Registered User

Join Date: Jan 2017
Posts: 4,575
Re: AC battery charger for AGM start battery and Lithium bank

Quote:
Originally Posted by Maine Sail View Post
I do like these chargers I just do not like the ProNautic or ProCharge Ultra for LFP.
So what is your reco now for charging LFP from mains/genny.

Have you seen / researched the shunt-managed Magnum units?
john61ct is offline   Reply With Quote
Old 13-06-2018, 08:02   #27
Sponsoring Vendor
 
OceanPlanet's Avatar

Community Sponsor

Join Date: May 2009
Location: Woolwich, Maine
Boat: Sold it!
Posts: 444
Send a message via Skype™ to OceanPlanet
Re: AC battery charger for AGM start battery and Lithium bank

We've been using the Sterling PCU's with success, however (as Mainesail points out) since the absorption cannot be set less than 1hr, we reduce the max charging voltage to 14.4/28.8, then set the Float @ 13.4/26.8.
__________________
Twice around was enough for me...
Now I just help others prep for ocean trips...
www.bruceschwab.com
OceanPlanet is offline   Reply With Quote
Old 13-06-2018, 08:05   #28
Sponsoring Vendor
 
OceanPlanet's Avatar

Community Sponsor

Join Date: May 2009
Location: Woolwich, Maine
Boat: Sold it!
Posts: 444
Send a message via Skype™ to OceanPlanet
Re: AC battery charger for AGM start battery and Lithium bank

However for most of our mains/genny charging we use Victron Multis, Quattros, or Skyllas, using their VE.Bus System Configurator interface. The Mastervolt Combis and some chargers can also be programmed appropriately using their PC-Link and Master Adjust software.
__________________
Twice around was enough for me...
Now I just help others prep for ocean trips...
www.bruceschwab.com
OceanPlanet is offline   Reply With Quote
Old 14-06-2018, 08:34   #29
Senior Cruiser

Cruisers Forum Supporter

Join Date: Mar 2014
Location: Anacortes
Boat: previous - Whitby 42 new - Goldenwave 44
Posts: 1,801
Re: AC battery charger for AGM start battery and Lithium bank

Quote:
Originally Posted by Maine Sail View Post
I do like these chargers I just do not like the ProNautic or ProCharge Ultra for LFP. There is no adjustment to the absorption duration, just voltage. Remember it's not just about adjusting voltages it's about adjusting duration at constant voltage. With LFP the ideal charge is charge to XX.XX volts then STOP...


On a group I am in just this morning another ruined LFP bank showed up, a 700Ah Winston pack overcharged to death and extracted from the boat apparently smoking and blown up like a balloon. Not the first not the last.




Again, would not be my first choice for LFP unless you are 100% manually managing it yourself. The algorithm is designed for lead acid where the longer it remains in bulk the longer the absorption cycle is, absolutely backwards for charging LFP. With LFP we don't want any absorption or no more than a max of about 30 minutes, depending upon target voltage..

Beyond that you could grab one at MarineHowTo.com and support the site rather than some random shop who does not support the community...

Also, IMHO the Echo is a poor choice as it will be a continual bleed on your LFP bank as it simply turns on at 13V and you'll rarely if ever dip low enough for it to ever turn off. You could put a switch in the house bank line or the negative and manually excite it but, a Sterling BB1230 Battery to Battery Charger is a far superior piece of equipment and it can be ignition key excited rather than voltage excited, does buck or boost, has its own actual smart charge profile, has a temp sensor etc..



MaineSail - all excellent points. I do think it is important to reward those who make contributions to us all on here and elsewhere. You have excellent pricing on your products on your website so I would get stuff from you if I need something. I did make a contribution to your website maintenance fund (like I do to CF) since that is a valuable resource for many of us. I did that last week.



I already had an Echo Charger from when I had my big AGM banks so hooked that up to my LFP bank. And then I took out the fuse and don't use it for the reason you give: it is always on since the LFP bank is almost always above the EC threshold voltage. I don't want uncontrolled draws from my LFP bank. I like the idea of ignition turn-on so I think I will use my engine pressure switch to switch the EC on when the engine is running.


If I was starting over I would definitely go with a B2B charger like the Sterling instead of the Echo Charger. However, it wouldn't do much as an alternate AC charge source, which I also need. So I am going to put in a ProNautic charger. I guess I had forgot you sold chargers at your site or I would have gone there to look first.



I intend to pretty much always manually turn on and off all charging sources. And to do the same for loads as much as possible. So in addition to having a largish DC breaker panel for loads, I also can turn on or off all my charging sources. Per your suggestions in the past I can turn off my alternator charging by turning off the power to the Balmar regulators.



I am still working on how best to manage the "oops" factor for when I don't set everything up correct for manually charging, e.g. leaving the solar on and then leave the boat. And I do have to leave the refrigeration system on so I need to protect for low voltage. So my biggest issue right now is how to protect from "oops" and intentional or unintentional absences from the boat. I will probably leave solar on if leaving for a day or two with the reefer still on and hope the solar regulator works per setup and does not push my cells too high, and then the BMS to protect that and from the cells getting too low.



I put in a relay for the solar but it was using too much juice just sitting there the way I had it wired. I am rethinking that while I move the regulator from an unprotected location in a lazerette to a dryer spot and a spot where I can actually read and reset the digital display. So I will leave it on and set the charging parms best I can and use a BMS for "oops".



Like someone else said above, we also are very used to monitoring for low voltage on our previous batteries so hope that living aboard we will manage to start charging when needed. I will turn off the alternators when motoring if the batteries are already charged to high "enough". But that is one thing that would be easy to forget on passages when you are tired and have to start the engines in a seaway or at night.



So a BMS of some sort to mitigate "oops" is my next thing to sort out. I have my old HousePower BMS that is all set to install but I would prefer something that is actually on the market now with some commercial cred. I will use a battery monitor to alarm and operate solenoids in any case but all the ones I have seen so far (not having exhausted my research) will only do an alarm signal for either high or low but not both. There probably are some that will be pointed out to me from a ten second web search (I hope).



So I am going to install the ProNautic 60A AC charger I have. I will set it up to charge the start battery with a switch to also charge the LFP bank (or through my parallel switch) in an emergency on a manual control basis. It will be my backup for the old Trace I/C charge function. (It puts out a solid 100-120A as long as I keep it on to the LFP but the fans start going on after 10-15 minutes.)


All other charge sources will go to the LFP bank and manually controlled as noted above. The Echo Charge will only go on when the engine is running but if I have the alternator regulators off I need to still monitor the LFP voltage although the amount going through the EC will be small. I just don't want it on all the time.


So far, I totally love my LFP battery and think I could manage it completely manual without a BMS. But Oops always happen at some point so I am going to keep looking at my options on how to manage that which may be with a LFP BMS or just voltage set point alarms/relays. And, complexity for integration and automation is not a good thing IMHO.



And, as noted, we should all support the gurus who give us major free support on here and elsewhere.
exMaggieDrum is offline   Reply With Quote
Old 14-06-2018, 11:38   #30
Registered User
 
CatNewBee's Avatar

Join Date: Aug 2017
Boat: Lagoon 400S2
Posts: 747
Re: AC battery charger for AGM start battery and Lithium bank

Quote:
Originally Posted by exMaggieDrum View Post
....


So far, I totally love my LFP battery and think I could manage it completely manual without a BMS. But Oops always happen at some point so I am going to keep looking at my options on how to manage that which may be with a LFP BMS or just voltage set point alarms/relays. And, complexity for integration and automation is not a good thing IMHO.



And, as noted, we should all support the gurus who give us major free support on here and elsewhere.
If you really love your LFP - GET A GOOD BMS AND LET IT DO ITS MAGIC INCLUDING BALANCING. Gurus are a good thing for believers. There is soo much nonsense in the forums about manual managing LFP. Just dont do it!

You can manually pump your bilge, but you hopefully have a automatic switch that drains it if necessary. You can manually control life values like oxygen, pulse etc, but in an ER they are monitored by computers.

You drop a significant amount of money for your cells, spend some 10..20% for a good BMS and bi-stable solenoids - like the BlueSea ML-RBS. This is a rewarding one time investment. Stop saving on the wrong end.
__________________

CatNewBee is offline   Reply With Quote
Reply

Tags
agm, battery, charger

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
Charging Lithium and AGM banks HKTim Electrical: Batteries, Generators & Solar 28 14-03-2015 23:54
New charger for a new AGM house bank Toubab Electrical: Batteries, Generators & Solar 1 26-04-2014 13:12



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 23:07.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.