Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rating: Thread Rating: 33 votes, 4.82 average. Display Modes
Old 20-09-2012, 16:57   #541
Registered User

Join Date: Jul 2011
Location: Australia NSW south coast
Posts: 616
Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Quote:
Originally Posted by ebaugh View Post
I think 13.8 float is too high? That's 3.45 volts per cell which is what I charge to at anchor, and then stop charging. But for a month in a marina? I think 13.4 is a better float voltage. This is probably about 85-90% SOC. It's my personal compromise to the manufacturers storage charge practice of using 50% SOC, a huge lack of good data on what "float" should be for LiFePO4, and an intent to remain in the 20-90% SOC window which may extend the cycle life. Does it matter? I'm not sure, but it won't hurt other than the capacity I sacrifice, which isn't needed anyway.

I've found the AGM setting works pretty well set for no absorption phase (if your charger has that). The voltage drop across the inverter/charger cables at 100A 14.4V works out to 3.45 to 3.5V per cell measured at the battery, then it switches to 13.4 float. This voltage makes it to the battery since the current flow is very small.


Bob
If the charger doesn't have battery sensing then this is probably ok but a back up cell logger alarm should be used to cover the posibility of a cell going over the 3.6v mark when fast charging at higher voltages, less likely with a number of cells in parallel as they tend to even each other out but a real risk in a small capacity single cells in series type pack.
The lower float voltage while constant shore power is available is quite a good idea, then fully charge the pack before setting off, the cells are really in storage mode when connected to a constant charging source.
The 13.8v float is for working batteries that are used and then recharged, solar also fits into this pattern.

T1 Terry
__________________

__________________
T1 Terry is offline   Reply With Quote
Old 20-09-2012, 18:49   #542
Registered User
 
ebaugh's Avatar

Join Date: Dec 2011
Location: On the boat
Boat: DeFever 44
Posts: 525
Quote:
Originally Posted by T1 Terry
If the charger doesn't have battery sensing then this is probably ok but a back up cell logger alarm should be used to cover the posibility of a cell going over the 3.6v mark when fast charging at higher voltages, less likely with a number of cells in parallel as they tend to even each other out but a real risk in a small capacity single cells in series type pack.
T1 Terry
Good point Terry. My cells have stayed right inline since fixing the BMS board issue I had. But there is nothing to say a cell imbalance could never happen. I think if you have more than 4 cells, the configuration should always be parallel first, then serial for 12V systems. Same with more than 8 in 24V systems.
__________________

__________________
ebaugh is offline   Reply With Quote
Old 20-09-2012, 22:50   #543
Registered User

Join Date: Nov 2011
Location: Fethiye Turkey
Boat: Lagoon 440
Posts: 3,164
Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Quote:
Originally Posted by ebaugh View Post
Good point Terry. My cells have stayed right inline since fixing the BMS board issue I had. But there is nothing to say a cell imbalance could never happen. I think if you have more than 4 cells, the configuration should always be parallel first, then serial for 12V systems. Same with more than 8 in 24V systems.
Looking at my battery layout does that fit in with your point here? Cheers
__________________
"Political correctness is a creeping sickness that knows no boundaries"
Lagoon4us is offline   Reply With Quote
Old 21-09-2012, 06:47   #544
Registered User
 
ebaugh's Avatar

Join Date: Dec 2011
Location: On the boat
Boat: DeFever 44
Posts: 525
Quote:
Originally Posted by Lagoon4us
Looking at my battery layout does that fit in with your point here? Cheers
The drawing you posted a day or so ago looks like what I'd call a 4 serial then 2 parallel configuration. That does not follow my suggestion.

What you may wish to consider is a 4 parallel then 2 serial configuration. I attached a picture of two possibilities.

The electrical difference is in your planned configuration there are 8 3.2 volt cells to balance. The suggested configuration has only 4 3.2 volt cells to keep balanced. Not probably a huge difference with 8 cells, but my config has 48 100ah cells.

The fuses in the one picture were recommended by my battery supplier. They isolate any cell that shorts out from the pack. I don't know anyone else who has done pack fusing. I did it because it was easy with GBS cells and adds some margin of safety. However, for what I believe to be a very unlikely event. But I still have fire extinguishers on the boat too.....

At under 200A pack loads charging or discharging, especially if you absolutely will not exceed 3.6 volts per cell or 120 degrees F ambient ever, I'm not sure the strapping is necessary. I only did it since it was recommended by my supplier. The EV guys routinely pull 2-3C under acceleration with their cars, with your bank that would equal around 2000 amps. In house bank applications, we just don't generate that kind of current and the related heat.
Attached Thumbnails
Click image for larger version

Name:	image-440275064.jpg
Views:	131
Size:	95.0 KB
ID:	46844  
__________________
ebaugh is offline   Reply With Quote
Old 21-09-2012, 08:47   #545
Registered User

Join Date: Nov 2011
Location: Fethiye Turkey
Boat: Lagoon 440
Posts: 3,164
Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

And 4 cells are then easier controlled by the previously suggested BMS. Side by side is more economic for available space. I'll probably strap, for peace of mind, to contain strongly in a seaway.

I should get a response back from the supplier regarding availability etc on monday then i'll draw up a shortlist of intended equipment from all the above for comment.
Cheers Frank
__________________
"Political correctness is a creeping sickness that knows no boundaries"
Lagoon4us is offline   Reply With Quote
Old 21-09-2012, 22:21   #546
Registered User

Join Date: Sep 2009
Location: Mackay,QLD, Australia
Boat: planning a approx 45ft cat
Posts: 3,405
Images: 3
Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Quote:
Originally Posted by Lagoon4us View Post

I can get these locally WB-LYP400AHA LiFeYPO4 (3.2V/400Ah) and would get 8 of them connecting to give a single unit at 12volt/800 amps for around $4000 AUD Delivered to Croatia, then as per 'Downunders link' i would fit the under voltage unit plus the 'Junsi' logger.

Cheers Frank
Boy a massive bank. 800Ah Lithium is equivalent to 1600ah AGM useabale..

You can get 700Ah with 4 x 700ah cells with less conectors etc. I have been thinking for myself around 600ah of lithium would be more than adequate and eq to over 1100ah Agm's.

Just a thought and lower cost.

What battery capacity do you have now??

John
__________________
downunder is offline   Reply With Quote
Old 21-09-2012, 23:22   #547
Registered User

Join Date: Nov 2011
Location: Fethiye Turkey
Boat: Lagoon 440
Posts: 3,164
Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

H i , the 700 amp batteries from my supplier are dearer! So the 800 amp is more economical...

We have 5- 135 amp Varta's that we have never seen better than 50% charge they are screwed.

Our boat has no gas so cooking is electric, i want to keep it that way it's really good, we have no oven BUT a Cobb and a BBQ on the back rail is the way.

Your link helped convince me back to Lithiums, thanks.

Options.....

Frank.
__________________
"Political correctness is a creeping sickness that knows no boundaries"
Lagoon4us is offline   Reply With Quote
Old 23-09-2012, 17:58   #548
Registered User

Join Date: Sep 2009
Location: Mackay,QLD, Australia
Boat: planning a approx 45ft cat
Posts: 3,405
Images: 3
Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Quote:
Originally Posted by Lagoon4us View Post
H i , the 700 amp batteries from my supplier are dearer! So the 800 amp is more economical...

We have 5- 135 amp Varta's that we have never seen better than 50% charge they are screwed.

Our boat has no gas so cooking is electric, i want to keep it that way it's really good, we have no oven BUT a Cobb and a BBQ on the back rail is the way.

Your link helped convince me back to Lithiums, thanks.

Options.....

Frank.

Just 400Ah Lithiums would give you more usable capacity than the 5 vartra135's.

Frank,

check out this thread from s/v Jedi From My Design to My Installation: New AC Power System

Very good relevant info on overall electrical installation. Nick is an electrical engineer.

cheers,

John
__________________
downunder is offline   Reply With Quote
Old 25-09-2012, 05:39   #549
Registered User
 
jram's Avatar

Join Date: Oct 2010
Posts: 41
Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

What a great thread! Thank you everyone for your contributions.
__________________
jram is offline   Reply With Quote
Old 28-09-2012, 02:01   #550
jff
Registered User

Join Date: Sep 2012
Posts: 13
Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Quote:
Originally Posted by T1 Terry View Post
The down and dirty fix while you wait for the makers to get their act together is to put 2 x 12v agm batteries in series to make 24v and fit them in parallel to the charging circuit of the regulator. This will trick the regulaor into thinking it's charging an agm battery, the agm will keep draining off the charge it receives to the lithium batteries.
Does the GenSun BMS have a low voltage charge cut system like the one that cuts the mains charger? That connected between the AGM batteries and the lithium batteries would protect the lithiums from over charging and the regulator from seeing nothing, it would see the agm batteries. If you do go to the 24v starter for the engines the batteries will have a use there and if the regulator manufacturer can't get their act together you could leave the whole thing hooked up that way.

T1 Terry
I havent made much progress on this issue, mainly because the regulator died.
Steyr are kindly supplying a rebuilt unit for the absolute bargain price of only 1350 euro, oh plus a few more for the 21% tax. Or I could wait a mere 8 weeks for the reg to be repaired by Iskra at an unknown price. You have to be pleased with such economical and efficient service from the manufacturer. Mind you, it may not be as quick if you were further away, both Steyr & Iskra are less than 1000km from here. At least I'll have a spare to play with.

The boat currently has 2 80amp 12v AGMs that can be paralleled for starting. If I add a 24v alternator, can I put the 2 agms into series to accept the charge, and use a tap from the centre to provide 12v for starting and the engine management system?

I could then also parallel them to the lithiums to take the charge from the IFG and also to provide emergency start capability.

Another consideration is whether to the alternator and the IFG at the same time. Depending on the alternator that could give me around 0.6-0.7C total charging capacity. On the other hand it might end up with some expensive smoke due to something I have no idea about!
__________________
jff is offline   Reply With Quote
Old 28-09-2012, 02:46   #551
Registered User

Join Date: Jul 2011
Location: Australia NSW south coast
Posts: 616
Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Quote:
Originally Posted by jff View Post
Greetings all
Quote:
Originally Posted by jff View Post

I'm new here, but it look like this thread has a wealth of knowledgeable contributors.
I have just installed 16 GBS 200ah cells, arranged as 2 24v batteries with Elites BMS system.

The major issue I have is with charging, in a marina my Victron 50A charger works fine, and is turned off by the bms system,but anchoring out is a problem.
The boat has a Steyr diesel with a watercooled flywheel generator that provides in theory 2 24v 80A outputs. Certainly when I tested the system in the marina it looked good, with the BMS reporting around 140a going into the cells. That was with the pack being at around 80% charged.

When I tried to recharge when the cells dropped below 3.2v, I ran into a brick wall. It seems that the regulator doesnt like being asked for more amps than it can provide, initially drops the output to around 30A, then shuts down completely. Not exactly the ideal situation.

I tried contacting Steyr who advised "the unit is operating correctly, we do not recommend using lithium batteries with this unit" which was a bit suprising since they offr a hybrid drive as well using the same alternator.
Does anyone know of a device that I can put between the cells and the alternator to limit the load on the alternator?


Quote:
Originally Posted by T1 Terry
The down and dirty fix while you wait for the makers to get their act together is to put 2 x 12v agm batteries in series to make 24v and fit them in parallel to the charging circuit of the regulator. This will trick the regulator into thinking it's charging an agm battery, the agm will keep draining off the charge it receives to the lithium batteries.
Does the GenSun BMS have a low voltage(and high voltage) charge cut system like the one that cuts the mains charger? That connected between the AGM batteries and the lithium batteries would protect the lithiums from over charging and the regulator from seeing nothing, it would see the agm batteries. If you do go to the 24v starter for the engines the batteries will have a use there and if the regulator manufacturer can't get their act together you could leave the whole thing hooked up that way.

T1 Terry


I havent made much progress on this issue, mainly because the regulator died.
Steyr are kindly supplying a rebuilt unit for the absolute bargain price of only 1350 euro, oh plus a few more for the 21% tax. Or I could wait a mere 8 weeks for the reg to be repaired by Iskra at an unknown price. You have to be pleased with such economical and efficient service from the manufacturer. Mind you, it may not be as quick if you were further away, both Steyr & Iskra are less than 1000km from here. At least I'll have a spare to play with.

The boat currently has 2 80amp 12v AGMs that can be paralleled for starting. If I add a 24v alternator, can I put the 2 agms into series to accept the charge, and use a tap from the centre to provide 12v for starting and the engine management system?

I could then also parallel them to the lithiums to take the charge from the IFG and also to provide emergency start capability.

Another consideration is whether to the alternator and the IFG at the same time. Depending on the alternator that could give me around 0.6-0.7C total charging capacity. On the other hand it might end up with some expensive smoke due to something I have no idea about!

cheers

John



Hi John,
You can’t centre tap between the two 12v batteries while charging them as 24v, one battery will be under charged and the other over charged. E.G, 2 x 12v batteries being charged at 14.4v each equals 28.8v. If one batteries discharged so it’s charging voltage drops to 13.8v while charging, 28.8v less 13.8v = 15v, so the other battery will be charged to 15v killing it.
Another possibility is fitting a 12v 2000w PSW inverter to the 2 paralleled 12v batteries and power your 50 amp Victron mains charger from the inverter.
This system could be switch off if not required when the other regulator gets sorted or it could be left running to fool the other regulator into thinking there was more voltage at the battery terminals like it was just a flat AGM battery….. that one might be a trial and ….. hmmm… the last error sounded rather expensive.

T1 Terry
__________________
T1 Terry is offline   Reply With Quote
Old 28-09-2012, 08:57   #552
Registered User
 
ebaugh's Avatar

Join Date: Dec 2011
Location: On the boat
Boat: DeFever 44
Posts: 525
Quote:
Originally Posted by jff

I havent made much progress on this issue, mainly because the regulator died.
Steyr are kindly supplying a rebuilt unit for the absolute bargain price of only 1350 euro, oh plus a few more for the 21% tax. Or I could wait a mere 8 weeks for the reg to be repaired by Iskra at an unknown price. You have to be pleased with such economical and efficient service from the manufacturer. Mind you, it may not be as quick if you were further away, both Steyr & Iskra are less than 1000km from here. At least I'll have a spare to play with.

The boat currently has 2 80amp 12v AGMs that can be paralleled for starting. If I add a 24v alternator, can I put the 2 agms into series to accept the charge, and use a tap from the centre to provide 12v for starting and the engine management system?

I could then also parallel them to the lithiums to take the charge from the IFG and also to provide emergency start capability.

Another consideration is whether to the alternator and the IFG at the same time. Depending on the alternator that could give me around 0.6-0.7C total charging capacity. On the other hand it might end up with some expensive smoke due to something I have no idea about!
John,

Center tapping the AGMs might work, if the engine management load is trivial. But your earlier idea of changing the starter too and adding a DC converter is better.

Most lithium batteries specify a max charge rate of 3C and a standard rate of either .5 or .3C. So you can charge at .7C, but I'm not sure why they have these two different specs. Maybe Someone else knows? I can't get past .2C with my chargers.

I think you are going to have to get some help from Steyr to figure this out. Why won't it work with lithium, and what needs to be worked around? What is max continuos current that won't fry anything?

Our assumption, if correct, is that charging lithium batteries overloads the regulator demanding more continuous current than it can supply. If that's the case, paralleling AGM and Lithium together in a closely coupled configuration won't solve the problem. The Lithium batteries will control the voltage of the battery pack unit and end with the same result.

There must be some way to regulate the charge rate of the lithium batteries keeping the Steyr output well within the limits of that expensive regulator. You might be able to do it by constraining the coupling/parallel wiring by adjusting the size and length of the battery cables limiting the current flow into the lithium batteries. Fat enough to not overheat, long enough to have a resistance drop where the output from the Steyr is limited.

I thought that maybe a solar charge controller might work, but it seems that they all need a higher input voltage to work. I did find this product:

http://www.richelectric.com.au/product_view.php?id=4

But I don't know anything about it...

Or like Terry suggested, use inverters to power chargers, but your going to loose a bit of efficiency in the round trip.

Bob
__________________
ebaugh is offline   Reply With Quote
Old 28-09-2012, 18:56   #553
Registered User

Join Date: Jul 2011
Location: Australia NSW south coast
Posts: 616
Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Another possibility is find out the max continuous output the alternator/regulator can handle and match that to a DC to DC charger of the same size, sterling make some top of the range stuff that are marine oriented but that would still require the 2 agm batteries in series to act as a buffer. What do the 2 agm's do that you have at the monent, are they for 2 seperate engine start systems and do they each have their own alternator charging them?

T1 Terry
__________________
T1 Terry is offline   Reply With Quote
Old 29-09-2012, 01:44   #554
jff
Registered User

Join Date: Sep 2012
Posts: 13
Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

I aree that a 28v strter is preferrred, but it not so simple getting information from steyr. I keep asking "Is there a 24v starter available" so far the responses have been why?, and we have a 24v alternator kit.

The 2 AGMs on board are purely for starting and engine load, charged by the alternator, with one acting as a backup that can be paralleled if necessary.

I found the Steyr electrical service manual online, which shows what the existing alternator is (Bosch) and those for the 6 cylinders which are Iskra, but unfortunately not the starter info. It also shows how comple thay've made the electrical system,including the Lucas (prince of darkness) CPU
__________________
jff is offline   Reply With Quote
Old 29-09-2012, 07:56   #555
Registered User
 
ebaugh's Avatar

Join Date: Dec 2011
Location: On the boat
Boat: DeFever 44
Posts: 525
I think you could have an electrical shop rewind an existing starter for 24V. I don't know what it would cost, but that's what NL does for their marine generators when they need a 24V one.
__________________

__________________
ebaugh is offline   Reply With Quote
Reply

Tags
battery, lifepo4, LiFePO4 Batteries, sailing

Thread Tools
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
LiFePO4 Batteries - Okay Tear Me Apart ;-) jallum Electrical: Batteries, Generators & Solar 395 03-12-2015 13:19
Voltage drop under load, amps read 99% ?? VVD Electrical: Batteries, Generators & Solar 25 28-06-2011 16:25


Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 09:19.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.