LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[hellosailor]

Dave, Cotemar has a point. Or you buy some copper bar stock, a hacksaw and a drill press if there's no reasonable machine shop around.

I expect that CALB isn't very concerned about US laws, but I think we have both federal and many state laws saying that if the merchant ships non-conforming goods, or goods you didn't order, it is THEIR problem to correct. Good luck enforcing a judgement in China...but you might look to see which laws apply to you and then suggest to CALB that if they don't follow them, it might be possible to have them barred from the US market. Might or might not be, but hopefully someone there will see that it is better to suck it up, than to risk this.

At 40A I'm thinking the perforated "pipe strapping" sold in hardware stores would be a good enough conductor. Ain't copper but for a few inches, it might work while you're buying time to debate with China. Holes pre-made. And then again, you may have plenty of contact area as it is, no need to kludge further.

[Cotemar]

Originally Posted by bdbcat

Cotemar....

Thanks for the idea. I can do that...

Do you worry about lack of flexibility? Maybe more important in auto application, with higher vibration potential....But this is going on a 50 ft motor yacht. Not too much vibration in the battery compartment.

Thanks
Dave

You do not have to worry about flexibility, because the interconnects are so short. If you take the DYI route you can cut a block of wood to make the form shown in the attached picture. Put your copper strip in the wooden block form and hit with a hammer to make the form.

EV-Power | Terminal Connectors for SE60AHA

[bill good]

have used flat aliminium bar from hardware store with good results. just make sure any anodizing is cut back (both sides).

off station... out of Australia & driving across USA!!!

Regards Bill

[ebaugh]

I considered drilling holes in copper bar. Ended up with a different style battery that has 4 screws per terminal. I think if the battery's are secure then copper bar or flat copper pipe will work OK. Just don't have the battery's where they want to move and the terminal connection is what holds them in place.

For what it's worth, the spec for my batteries is a 3/4 inch wide, 1 mm bus bar is good for 100 amps.

Be careful how you connect them, on the outside ends near where you put the 12V taps, you might have more amps than you think.

[s/v Holiday]

Hi Dave,

I feel for you as I just took delivery of my 32 cell 100ah lifepo4 battery's and they came with no interconnects. I have looked around the Internet as was not able to find interconnects being sold by themselves so I have decided to make mine out of marine tinned copper battery cable with but connectors. I got it from zdeals.com at a good price and will start crimping tomorrow. I was going to use copper strap but I am concerned about corrosion in the salt environment. I will post some pics when I get them installed.

Good luck,

CJ

[bcn]

Dave,

you should use connector bars with some flexibility for
a- vibrations, what you already mentioned
b- the "breathing" of the cells as those have just their plastic housings as all the far east brands. Charging and temperature will make themto move a little bit. Due to that issue the framing of the cell is recommended as well.

I'm about to order a 24V housebank here:
Products - cleanenergy GmbH

and if you specify the distance between the cells required they might have the appropriate bars to ship those (will not be 500 units). Shipping cost from EU might be another issue.

Hubert

[ebaugh]

Well it's finally installed. I think I was able to attach a couple of pics with the iPad app.

48 100 Ah cells, 12P, then 4S. I decided to install a BMS against the conventional wisdom in this long thread. But it's primary purpose is the monitor at my electric panel where I can see cell voltages. And it will also pull the plug if I do something stupid and overcharge or over discharge.

The remaining 2 Trojan batteries have become my engine start batteries. The little black box on the right is the Charles Start Now product that should combine the batteries if the engines are running so the alternators can charge/maintain the lithiums underway where all the house loads are.

One design flaw is my Magnum inverter has a Full Charge mode I did not know existed. While you can set custom charge and float voltages, after a few hours at Float, there is hard logic that turns off the charger until the voltage reaches 12.6V, then it resumes float. The intent is to not boil away flooded batteries at dock. But for lithium, it would do almost a full discharge/charge cycle. There is no issue at anchor, just extended time on shore power. The latest firmware with latest remote controller combination has an option to defeat this logic. But anything over a year old probably needs an upgrade. I have little dock time the next few months, and other chargers, so I'm going to wait to upgrade.

I will be happy to answer any questions on the system installed....

I have a question....

I balanced the cells out of the box, and again once configured into the full pack configuration to 3.55V. They floated to 3.35 in sync. Then I ran a small discharge test of about 100 Ah and charged. At the end, one cell was at 3.39V and the rest at 3.48V. Seemed like a big difference, but I think they will merge with more cycling. What is the experience of others here?

I charged that cell back up to match, and they have floated right in sync since.

As a note, 100 feet of 16 gauge wire makes both a nice shunt to discharge a cell by shorting it through the wire and with an isolated 6V battery to charge a 3V cell. Just be sure to isolate the 6V battery. Intermittent duty only....

[Hyprdrv]

Ebaugh,
Just Beautiful!!
I assume your running in parallel?
12V at 4800AH?
What batteries are you using, I don't see any terminals on top of those?
Did you strap the batteries together and how are you holding them down?
Which monitoring system are you using?
Any solar?
What is the function of the "Inverter" as a charge source, in other words what is it doing as an inverter to charge? I'm looking a Propulsion bank at 144V but at 200 AH ea. so it's nice to see this setup.

Thanks,
Steve in Solomons MD
Lagoon 410 SE

[T1 Terry]

Originally Posted by bdbcat

Folks...

First post, read the whole thing first. Good reading.

Just took delivery of 12 pcs CALB 180AH cells.
Unfortunately, the wrong bus bars were shipped. Too short. sigh.....

CALB offers to replace the bus bars if I send them back to China first. Now, shipping $50 worth of copper halfway around the world, twice, in order to enable a $3K battery bank makes no sense to me.

I need to make forward progress on this project. So, I modify the short bars by opening their holes so that they fit, albeit with somewhat less contact area. In my configuration, I expect to see only about 40A max through each bar, so should be OK. But not great....

I ask CALB to sell me new, correct bus bars at full retail. What's $50 in the grand scale? No can do. 500 pcs minimum quantity without cell order. sigh again.....

And so we come to my question:
Anyone know of a source for CALB 180AH cell interconnects, or an economical flex braid interconnect good for 40-50 A?

Thanks
Dave

Hi Dave,
Probably a little late now but you can buy the braided cell links here EVTV Motor Verks Store: Battery Connections Jack Rickard does an on line TV show about building electric vehicles and found the same problems with getting the right bits so he has started an online shop for those people in the US. In Aust you can buy the bits from a number of suppliers, 2 in Western Australia EV power and EV Works and one in far Nth Queensland, Basicly Natural.

T1 Terry

[T1 Terry]

Originally Posted by ebaugh

Well it's finally installed. I think I was able to attach a couple of pics with the iPad app.

48 100 Ah cells, 12P, then 4S. I decided to install a BMS against the conventional wisdom in this long thread. But it's primary purpose is the monitor at my electric panel where I can see cell voltages. And it will also pull the plug if I do something stupid and overcharge or over discharge.

The remaining 2 Trojan batteries have become my engine start batteries. The little black box on the right is the Charles Start Now product that should combine the batteries if the engines are running so the alternators can charge/maintain the lithiums underway where all the house loads are.

One design flaw is my Magnum inverter has a Full Charge mode I did not know existed. While you can set custom charge and float voltages, after a few hours at Float, there is hard logic that turns off the charger until the voltage reaches 12.6V, then it resumes float. The intent is to not boil away flooded batteries at dock. But for lithium, it would do almost a full discharge/charge cycle. There is no issue at anchor, just extended time on shore power. The latest firmware with latest remote controller combination has an option to defeat this logic. But anything over a year old probably needs an upgrade. I have little dock time the next few months, and other chargers, so I'm going to wait to upgrade.

I will be happy to answer any questions on the system installed....

I have a question....

I balanced the cells out of the box, and again once configured into the full pack configuration to 3.55V. They floated to 3.35 in sync. Then I ran a small discharge test of about 100 Ah and charged. At the end, one cell was at 3.39V and the rest at 3.48V. Seemed like a big difference, but I think they will merge with more cycling. What is the experience of others here?

I charged that cell back up to match, and they have floated right in sync since.

As a note, 100 feet of 16 gauge wire makes both a nice shunt to discharge a cell by shorting it through the wire and with an isolated 6V battery to charge a 3V cell. Just be sure to isolate the 6V battery. Intermittent duty only....

I can only count 42 in the photo, where did you hide the other 6? A 1200Ah 12v pack is serious stuff, a very neat looking job too. With the cell balancing, charge the cell packs to 3.6v but limit the voltage so it doesn't go any higher, hold it there till it stops absorbing any more current. Disconnect it and charge the next set and so on till all 4 sets are charged to 3.6v. Let them settle over night and they should still be 3.5v or higher, if not, do it again. The problem is you have a lot of cells in parallel and you need to get all of them full, you only need to this the first time and there will be no problems from then on. When the cells are new some are just slower than others to take up the charge, a 0.2v over charge won't create enough heat to cause any problems but will make the lazy cells take up the charge, just one of those things with big parallel packs.

What cell voltage monitoring equipment are you using?

T1 Terry

[ebaugh]

Originally Posted by Hyprdrv

Ebaugh,
Just Beautiful!!
I assume your running in parallel?
12V at 4800AH?
What batteries are you using, I don't see any terminals on top of those?
Did you strap the batteries together and how are you holding them down?
Which monitoring system are you using?
Any solar?
What is the function of the "Inverter" as a charge source, in other words what is it doing as an inverter to charge? I'm looking a Propulsion bank at 144V but at 200 AH ea. so it's nice to see this setup.

Thanks,
Steve in Solomons MD
Lagoon 410 SE

12V at 1200AH. There are 12 in P for 3.2V at 1200AH then 4 of those in series for 12V.

The terminals are under the plastic covers. The batteries are GBS cells, made in China and distributed by Elite Power in Phoenix. You can Google for their website. They have several dealers in the US. I got mine from Electric Blue Motors in Flagstaff.

The monitoring system is also sold by Elite. But I think they only package it with their batteries.

No solar yet, but it's at the top of the list when there are future funds available. Unless I improve my refrigeration too, I need 1000 watts minimum to make solar worthwhile.

I should have said inverter/charger....all in the same box.

The batteries are sold strapped in 4 cell groups, wired in series for 12V. I had to unstrap them to flip cells and then put them back into the same straps.

My boat has many things that would require rework to survive a 360 degree roll....hope I never see that. Up to about 90 degrees we will be OK. The batteries are secured to prevent sliding around with wood wedges in the box, but would not survive being upside down.

Regards, Bob

[ebaugh]

Originally Posted by T1 Terry

I can only count 42 in the photo, where did you hide the other 6? A 1200Ah 12v pack is serious stuff, a very neat looking job too. With the cell balancing, charge the cell packs to 3.6v but limit the voltage so it doesn't go any higher, hold it there till it stops absobing any more current. disconnect it and charge the next set and so on till all 4 sets are charged to 3.6v. Let them settle over night and they should still be 3.5v or higher, if not, do it again. The problem is you have a lot of cells in parallel and you need to get all of them full, you only need to this the first time and there will be no problems from then on. When the cells are new some are just slower than others to take up the charge, a 0.2v over charge won't create enough heat to cause any problems but will make the lazy cells take up the charge, just one of those things with big parallel packs.

What cell voltage monitoring equipment are you using?

T1 Terry

If you can see the shunt at the bottom and Trojans at the top, count again....I get 48?

I only have 8 of the 48 cells with BMS boards. They act as balancers, voltage and temperature monitors. Only one set of 4 is plugged into the BMS. The other is a spare. I have a few balance only boards I did not install. The shunting ability of these boards is trivial. When I unpacked the cells, I set them up 4 cells in series, then 4 in parallel to do the initial charge and had balancers on all the cells. With a 60A charger, once it hit 3.55V, the balancer engaged, but only slightly delayed the voltage spike above 3.6V. The charge rate had to be well south of 10A before they had much impact in that configuration but even then, the cells had to be pretty close, all above 3.5V for the balancers to work. Maybe in a broken in pack it would be enough.

Ultimately, I'm adopting your 3.45V top of charge plan, but I will manually top balance another time or two and see if things improve.

The BMS monitors cell voltage and opens the solenoid at above 3.7V and below 2.9V. There is also a second page on the BMS/EMS display that shows cell voltage and temperature.

Bob

[T1 Terry]

Hmmm.... it appears my maths and port don't mix too well I think every system needs some form of BMS, it's the cell balancing units and BMS charger control I have issues with, far better for the BMS to be at a cell voltage monitoring level and simply turn things off as a back up type system rather than a part of the control system.

even if you had a bit of solar they would do that final top up charge that helps balance the pack but any system has room to evolve. Congratulations on the neat work.

T1 Terry

[ebaugh]

Terry,

Thanks! I appreciate the effort you and many others made to this thread. It was a great help as I navigated the technology. I hope to post some glowing reviews after I have a bit more experience putting things to work. Bob

[bdbcat]

Bob...

I really like the look of the EMS panel you have. LCD display, switches, etc.

I see nothing like that on the Elite webpage. I do see the guts, however. Did you build the panel from scratch?

Thanks
Dave