LiFePO4 for House bank final designs

[snarron]

Originally Posted by 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

Gary, Sorry! Just found the NORDYKE link, all is well! Thank You!

[TeddyDiver]

Originally Posted by 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 ?

#1 Faster recharging. With a generator or with a big alternator you can charge your batteries as fast as you feed the power. Can pretty much cut the running times more than half..
#2 No need to top up the batteries, no need for solar for day time topping.

[gpeacock]

Originally Posted by snarron

Quote:
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

Mainsail covers both Top and Bottom ballancing on the last third of his first page here: LiFePO4 on Boats
Entropy covers it briefly on their page Here
Nordkyn Design's Page does the best job I've seen in explaining the whole issue of Balancing
All these guys spent a tonne of time researching, thinking and then making decisions on their systems. They then went the extra mile and spent even more time to write it down for the rest of us. It's worth reading all of their series from start to finish.
Speaking of great websites that explain their setups: WHO ELSE HAS ONE TO LIST HERE

PS: Snarron sorry, missed your second post. No apologizes needed. Its a lot of information to digest and summarize which is why this thread is trying to exist in the first place.

[StuM]

Originally Posted by TeddyDiver

#2 No need to top up the batteries, no need for solar for day time topping.

Also - coulombic efficiency around 95% rather than 70% for LA, so you don't need to generate as many Ah to replace what you use.

And, you can use all of your solar availability to top up the batteries rather than wasting a lot of it while trickling in charge for the last 10-15%.

(Don't believe people who say that they can use LA overnight and be "fully recharged" on solar by mid-day - it takes hours to get that last bit in, regardless of how much solar they have.)

[offpist]

Originally Posted by snarron

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!!!

It consists of 4 pcs 1000AH Winston cells.
I got them from here:
EV-Power | WB-LYP1000AHC LiFeYPO4 (3.2V/1000Ah) Special product

And BMS from here:
REC d.o.o.

Two Tyco EV200 relays controll charge and discharge.

Had it for 1,5 years now, and works flawless.
We even stopped using gas, only cooking our food on induction top off the 3000W inverter..

[offpist]

Originally Posted by gpeacock

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.

This smaller Lifepo4 battery is located in front of the boat.
It consists of 8 pcs 115AH Heter cells in an 4S2P setup.
Together with service battery using Mastervolt Battery Mate.

Having two batteries with same technology just makes things lot easier than combining lead and LIFEPO4.

The start battery also has an Mastervolt shunt. So an High Voltage event on the start battery will shut down all charging units onboard over the Masterbus network. This will not normally happen.


Oh, and we made this local intervju and we got an idea, lets charge the electric car from the boat. That would be fun..

https://www.youtube.com/watch?v=Sf0E7I5QBOA

[arsenelupiga]

Originally Posted by StuM

Also - coulombic efficiency around 95% rather than 70% for LA, so you don't need to generate as many Ah to replace what you use.

And, you can use all of your solar availability to top up the batteries rather than wasting a lot of it while trickling in charge for the last 10-15%.

(Don't believe people who say that they can use LA overnight and be "fully recharged" on solar by mid-day - it takes hours to get that last bit in, regardless of how much solar they have.)

thanks gents. get it. i have just done serious crash course on diesels and not interested in batteries right now. Next one will be gel, same as original lagoon. Maybe one after next ...

Learning how to trim sail appears more fun for electrical imbecile like me.

[Emerald Sea]

Originally Posted by arsenelupiga

What am I missing here ?

The key point has been omitted: available/usable energy. With LiFePO4s you have significantly more, or say, longer usable power available to you for an equivalent Ah battery bank. You can take LiFePO4s down to circa 20% SOC without any loss of voltage.

[StuM]

Originally Posted by Emerald Sea

The key point has been omitted: available/usable energy. With LiFePO4s you have significantly more, or say, longer usable power available to you for an equivalent Ah battery bank. You can take LiFePO4s down to circa 20% SOC without any loss of voltage.

I think that point was a given in the original question:

"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. "

He understood that you get a lot more than 30% usable out of LiFePo - so don't need as many Ah of storage - that was where the weight saving came from.

[snarron]

peacock --> THANK YOU!

offpist --> THANK YOU!

1 concern, NORDKYN post by peacock alludes to possible/probable issue with such large cells from vibration and banging on a boat in typical seas. Any worries here or issues yet? The "strong" recommendation of using only 100-200AH prismatic's! Any comments by any forum readers?

Sincerely,S Narron

PS-offpist - cute little one!

[offpist]

Originally Posted by snarron

1 concern, NORDKYN post by peacock alludes to possible/probable issue with such large cells from vibration and banging on a boat in typical seas. Any worries here or issues yet? The "strong" recommendation of using only 100-200AH prismatic's! Any comments by any forum readers?

We made an well supported frame for our 1000AH cells and i am not worried about them getting Physical damage from heavy seas.

Having many small celles makes for a lot more bus-bars and connections, and those can also fail. So for me it made more sense to fit big cells instead of many smaller ones. I never heard about an cell failing internally, if so it must have been installed very badly.

I have helped 3 other boats install similar system (using 1000AH cells) and they are cruising the world now with no issues, so far.

[mbartosch]

Quick update on the installation on Entropy:

1. documented alternator installation (not 100 % on topic but I consider it a necessary component of my LiFePO4 installation)

2. I was made aware by Jim (many thanks!) in the Blog comments that the Balmar Digital Duo (which I used for charging the starter battery in my design) is not actually a DC/DC battery charger with step-up capability, it is in fact an intelligent switch. This was confirmed by Balmar support in a reply to my query.
I was totally unaware of this fact.
I will replace the Digital Duo in my design with a Sterling Power Pro Charge B BBW 1212 (a real DC/DC charger with step-up). This device also features a dedicated on/off input (activate with +12 V) and should be a drop-in replacement for the Duo in my design.

[gpeacock]

Great update by mbartosch, keep em coming!
exMaggieDrum, have you got your cells yet? Are you ready to post your final design? Inquiring minds want to know

[exMaggieDrum]

Originally Posted by gpeacock

Great update by mbartosch, keep em coming!
exMaggieDrum, have you got your cells yet? Are you ready to post your final design? Inquiring minds want to know

My cells are on order but not arrived at the vendor yet. I have been reluctant to bug them too much but will next week to get a status update. It may be a few more weeks. Evidently shipments from China have been problematic, I suspect because of the "new" shipping requirements, but it may be something else. I have my power supply and am eager to start balancing them.

My design seems to be as firm as mud right now. It seems to change (in small details) with each week of new posts by those with questions and the answers by the more learned of the group. There is definitely more to this than even what I expected when I started.

However, I had decided this morning before seeing your post that I need to start committing my sketches to diagrams on my Mac this week. I do have a top level diagram ready (until it changes). I'll post it next.

[exMaggieDrum]

My current high level diagram (subject to change of course):