LiFePO4 for House bank final designs

[gpeacock]

Originally Posted by mbartosch

Thanks for linking our Blog - I was a bit too lazy to post new articles lately, but will do so in the near future.

Some answers to your initial questions:

Thanks for posting!
Yeah I was hoping posting your blogs would bring you out. You guys are the pioneers and your experience (plus the enormous time you spent documenting it) greatly helps us all.

2.3 A pulled over a 24 hour period is too much for my solar to keep up with. In addition to the coil economizers, I wonder if there is a way to reduce that load by only powering the relays that have a reason to be powered. Some sort of loop from the charge source that powers the relay and then leaves it up to the BMS to shut it off if need be...

I really like the idea of the lazy charging logic... This could get pretty complex though because your calcs would need to include the fact that solar is only available during the day....

[exMaggieDrum]

Great thread and posts! This is a good adjunct to the massive LiFePO4 thread on here.

[Emerald Sea]

Originally Posted by gpeacock

. Based on your description and schematic I see you have your batteries configured as 2 banks. I assume the mastervolt BMS with each uses the Latching relays to disconnect when charged or discharged. Does the BMS alarm before these events? If there is a LVD do you have a way to override the system to allow for charging?
Thanks for sharing
Gary

Yes, the MasterVolts system (MasterAdjust) allows you to set a pre-low (LV) alarm in addition the actual LV alarm. I have the pre-low set for 30% and LV to 20%. The pre-low is a loud buzzer alarm and the system can be overridden to allow charging. Effectively, I would have the delta of 10% to shut down loads and start a frantic search for a charge and/or correct whats busted!

[offpist]

Mastervolt actually has a lot of nice functionality good for LIFEPO4.
The Mastershunt have Lithium program and calculates the SOC quite good, (but not on cell level ofcourse). With the mastervolt relays you can setup a lot of different events.

Like turn off alternator at 90% SOC, or High voltage event.
Turn off watermaker at 20% SOC, or at an set time. (then you can actually leave the boat and it will turn off after set time, in my case 3 hours).
Turn off inverter after 20% SOC, or Low Voltage event.

Also the Mastevolt Regulator can switch to float mode at an set SOC.
I configured this to 90% SOC, and the Float Voltage to 13,35V.

So the mastervolt system is pritty much controlls everything. and the BMS is just in the background if everything else fails.

[gpeacock]

Originally Posted by offpist

So the mastervolt system is pritty much controlls everything. and the BMS is just in the background if everything else fails.

Wow, you can program it based on SOC. I assume that means you can use it to set up charging systems start up and shut off at say 20% and 90%. From what Im reading actually cycling these batteries is a good thing.
Good stuff!
Thanks
Gary

[offpist]

Yes, you can set it to voltage of course, but also limit charge and discharge within SOC%.


Then there is the Masterbus to NMEA2000 interface that lets you display everything on all NMEA2000 devices..

Even the temperature and field current to both alternators are displayed. (200A+160A)

We have 1000AH Lifepo4 as Service battery, and 230AH Lifepo4 for start/windlass/thrusters.

[snarron]

Originally Posted by offpist

Yes, you can set it to voltage of course, but also limit charge and discharge within SOC%.


Then there is the Masterbus to NMEA2000 interface that lets you display everything on all NMEA2000 devices..

Even the temperature and field current to both alternators are displayed. (200A+160A)

We have 1000AH Lifepo4 as Service battery, and 230AH Lifepo4 for start/windlass/thrusters.

What does the 1000AH Setup look like and who make them? Where did you get it/them? How much $$ and how long have you had it/them? Much thanks in advance for this info!!!

[gpeacock]

Originally Posted by offpist

We have 1000AH Lifepo4 as Service battery, and 230AH Lifepo4 for start/windlass/thrusters.

Hey Offpist. You mentioned you have a 230AH bank for start/windlass/thruster. Where is this bank located and how do you charge it?
This is one of the things I have yet to finalize in my design. My thruster pulls 500A at 12V so without changing wires it should go forward. The cost of a whole separate bank system(with or without BMS) gets prohibitive though and most LiFePO4 batteries arent happy at more than 2 or 3C which means I need to buy a 250AH bank for max 20 seconds of thruster goodness. Seems like a waste.

[snarron]

One other pressing question? Any info on procedures for "Top Balancing LiFePO4 batteries, as single cells upon arrival prior to hooking up in series/parallel, or as assembled set?"

Please HELP! Thanks in advance!

[gpeacock]

Originally Posted by snarron

One other pressing question? Any info on procedures for "Top Balancing LiFePO4 batteries, as single cells upon arrival prior to hooking up in series/parallel, or as assembled set?"

Please HELP! Thanks in advance!

If you haven't read ALL the links I posted earlier in this thread, do so. There's lots of great info on balancing the cells there.
Gary

[lonesoldier0408]

Oooops

[gpeacock]

Originally Posted by lonesoldier0408

Has anyone heard of Cobalt Batteries.?

Thread drift Alert!
Offpist: You can do cruisers Forum a great service and get us back on track by having a look at my original thread question *** here *** and posting your answers. Your system sounds fantastic and I'm sure lots want to hear how it's set up.
Thanks
Gary

[exMaggieDrum]

Originally Posted by mbartosch

Thanks for linking our Blog - I was a bit too lazy to post new articles lately, but will do so in the near future.

Some answers to your initial questions:

Size of the bank: 400 Ah (4P4S 100 Ah Winston LiFePO4)

Bank/BMS completion: 09.2015

BMS: HousePower BMS with dedicated Low and High Voltage Cutoffs and a dedicated main contactor; LVC central, HVC "distributed" between charging sources. LVC warnings are generated by watching computed SoC. HVC should not happen normally.

Alternator protection: HVC indirectly cuts field current; B+ directly connected to battery. No wind/hydro generator, so no similar problem there.

Contactors/Relays: Tyco Kilovac EV2000 (LVC); 100 Amp rated relay for solar HVC; standard 12 V and 220 V relays for cutting alt field and charger shore power supply.

Standby consumption of the entire boat: around 2.3 A. (Will subsequently work on reducing this by building coil optimizers for the various always-on 12 V relays.)

Starter battery: traditional Lead Acid. Charged by DC/DC charger from house bank, charging triggers on one of the following events: ignition on, starter battery voltage lower than defined threshold, starter battery estimated SoC lower than defined threshold. Charging is maintained for at least 30 minutes after trigger disappears.
Dedicated small shore power charger, directly connected to starter battery to keep starter battery up without having to power up the house bank ("away from boat storage mode").

Charging settings: all charging sources set to values between 13.8 (Victron Inverter/Charger, Victron BluePower solar chargers) and 14.0 V (Balmar MC 614/Alternator) for absorption, 13.3 V for float.
MC 614 senses alternator temperature via thermo sensor, in addition belt manager dials down field current to 80 % (subject to more detailed adjustments).

Other thoughts: This design has been criticized for being too complex and I agree that it may be over the top for some people's needs.
However, I really had fun designing it, and being an EE I enjoy making things work the way I want them to. I am able to fix any problems myself and have spares and a plan B for almost any failure I could think of, hence no doubts about complexity in my camp.

I am currently working on adding some logic to keep SoC of the bank automatically in the 40 - 80 % range in what I call "lazy charging mode". This mode simulates HVC when reaching 80 % SoC and disables the simulated HVC event when reaching a predefined lower level (e. g. 40 %).

This "lazy mode" can be manually disabled for longer passages when extracting every single Joule from available charging sources becomes important.

Our portable battery packs (I built two 40 Ah LiFePo4 batteries complete with BMS in water resistant cases, normally driving the electric dinghy outboard or other 12 V loads such as pumps or soldering irons...) can be hooked to the load bus on a "battery pack recharging station" in the aft locker box.
(The nice thing is: when left switched on there, they effectively expand the capacity of the house bank by an additional 80 Ah - they absorb charge and deliver current to the system.)

I am currently going through your blog posts and diagrams in detail for about the 4th time. Your system is indeed very complex. What I love is that you explain why you have done everything and indicated which parts you think are optional and those you don't. I have refined my understanding of a "proper" DIY system doing this. I have thanked you before but I will do so again now. I encourage anyone who is doing this to take a look. It can be intimidating if you are not good with wiring diagrams and concepts. But if you are you may be should not be DIYing a system.

P.S. I just put in an order for my cells and am excited like a kid on Christmas Eve! I am getting the last few parts for my BMS design and am currently doing the physical layout for wiring, terminal strips, the HP BMS, relays, and such. Quite fun actually.

[arsenelupiga]

i fail to understand excitement about lifepo batteries.

Compared to my current 4x gel, 480 AH, that weight 160 kg, and have usable 30% of energy = 144 h, LifePO from what I understand provides same power at 1/3 of weight. Saving 100 kg is nice, but seem just a bit to much mess for the benefit.

Gel lasts 6-9 years, same as lifepo.

What am I missing here ?

[snarron]

Quote:

One other pressing question? Any info on procedures for "Top Balancing LiFePO4 batteries, as single cells upon arrival prior to hooking up in series/parallel, or as assembled set?"

Please HELP! Thanks in advance!
If you haven't read ALL the links I posted earlier in this thread, do so. There's lots of great info on balancing the cells there.
Gary

Have looked thru all of it. I must have missed the specific methods to balance new cells! Can you specifically list your posts where you explain "TOP BALANCING" in some detail, Please. I'm not trying to be short, but I have looked in earnest, but might have missed it. I do glaze over late at night reading all the posts!


Sincerely, snarron