BigBattery.com 48V LAMA - LiFePO4-115Ah-5.3kWh

anonymous

New Member
Hi,

I was looking for a good deal on a battery that I could actually order and receive quickly back in June. I've settled on BigBattery's LAMA. It seemed like a good deal, provided that everything was as advertised. I'll tell you guys what happened and request your comments about it.

More information about the battery is at https://bigbattery.com/products/48v-lama/.

The battery was shipped quickly and was delivered 10 days after the order. Unfortunately, the R&L driver delivered the battery to the wrong address and I've got some lab equipment shipment instead. Luckily, the situation was rectified the next day and I've got the correct shipment. However, it looked like the shipment was opened, so, it would be impossible to say whether the defects I saw were there initially or were created by the person who received my battery the previous day.

I immediately saw something was off with the battery.
1. The battery dimensions and weight were different than what was stated on their website. BigBattery later corrected their website, however, their specs PDF still has the wrong dimensions.
2. The battery was missing screws, had stripped, mismatching screws and minor cosmetic issues. It is possible the first guy who had it tried to take it apart.
3. It felt like something was hitting the battery wall when I tried to move the battery around.

I tried to call and email BigBattery customer support, however, the only way I was able to reach them quickly and reliably was the live chat on their website. They did respond to my email a few days later, but it was kind of late. Anyway, they said that their website was wrong about dimensions but they did agree to replace the battery free of charge due to the missing screws and such.

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The whole process took a couple of weeks but I finally had my replacement in July. They did keep the anderson connector that came with the battery that I sent back but they did graciously agree to FedEx one over quickly.

The new battery was in much better shape but I still could feel something hitting the wall of the battery when it was moved around. BigBattery support did suggest I open it and see what it was. It turned out to be a long piece of thick wire running down the battery that was strangely not secured.

Once I had everything ready, I commenced with the testing.

One minor issue that I ran into was the current display on the battery. It always shows random numbers that change occasionally. Whatever the reading is, it is not current. The voltage display does work correctly, so, at least there is that. I asked BigBattery support about it and they suggested I reset the BMS. I followed their instructions but it did not fix the issue with the current display.

The second issue I ran into was lack of SoC data in their specs sheet and their website. They did say that 10% was 43V and 20% was 44.8V. They said "We have a sheet that we use here that is as close as we know for the batteries, but we do not offer that out to customers as it is not 100% accurate". They also said they don't have any battery performance characteristics charts.

I did all the testing with Growatt SPF 3000 TL LVM ES and this shunt meter. Numbers coming out of the Growatt were off, possibly due to incorrect battery voltage and current readings. I think the shunt meter did a much better job.

I configured the Growatt to switch to utility once the SoC was roughly 20%. I would reset the shunt meter roughly when the battery just started discharging in the evening. I would come back in the morning and check what the meter reading was.

Test #1:

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Test #2:
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(ignore the 0.7A current draw, it seems to be an issue with the Growatt, it does not invalidate the test)

According to my calculations, the capacity of this battery is better than the advertised 5.3 kwh. Someone correct me if I am wrong.

I tried to get BigBattery support to tell me what cells were in the battery, however, they wouldn't say much except that they are "A123 lithium iron phosphate cells".

It was time to take a look inside to get more answers.

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To be continued...
 

anonymous

New Member
Apparently, the main cell block is extended with an additional one in a lower level.
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I see a couple of issues. The thermocouple and the conductor is lose and the lower module isn't fully secured in its space at the bottom.

If someone could help me find the specs documents for these cells to try to determine this battery's performance characteristics, I would appreciate it. I think these are the cells displayed on the manufacturer's website: http://www.a123systems.com/automotive/products/cells/

Also, I suspect the charge voltage, low cutoff and SoC voltages might not be correct.

One other problem I've hit is this battery is heavy (140 lb). It needs two people to handle it.

What do you guys think about this battery? Is it worth the price? Should I order another one to meet my capacity requirement?

Any input is welcome. Thanks.
 

Greendream

Off-grid Beginner
I have three of these batteries in my off grid shed. They are 14S batteries and have different charge settings than 16S batteries. I charge mine to 49.6 volts and have low volt cutout at 43v. They are working fine but one of the three gets very warm. Tech support had me remove the lid to see where the heat is coming from and I identified the BMS as the culprit. Sent them videos showing the temps on the fluke. Still waiting for a resolution as we are concerned. Tech support in email hasn't been as responsive as I'd hope for $6k worth of batteries.

Interesting what you've shown on the inside, Ive only seen under the lid.

I don't have equipment to do capacity tests but they seem to at least be in the ballpark.

Thanks for posting your experience.
 

anonymous

New Member
I did not open the big pack, but I would assume they must be the same. They look the same from the side.

I felt around the outer sides of the battery while charging and discharging it but it seems to be the same temperature as the surrounding area. The local temperature was 40C/104F in the last few days but that doesn't seem to cause any heat issues.

The big pack appears to have connections for coolant lines, unless I am mistaken.

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anonymous

New Member
So, according to my calculations, these cells must be the '20Ah NanoPhosphate' LFP cells listed at http://www.a123systems.com/automotive/products/cells/.
The big pack claims 42.9V and 5148Wh in 13S6P configuration. There would be 13 series subunits of 6 cells connected in parallel.
Cell voltage: 42.9V/13 = 3.3V
Cell capacity: 5148Wh/13/6 = 66 Wh; 66Wh/3.3V = 20Ah

The battery is extended with an additional 6P unit connected in series with the big pack to make up the 14S6P configuration of the battery. The battery capacity would be 5544 Wh, 80% of which is 4435.2 Wh. My tests have shown ~4500 Wh at ~45V, which probably means I am discharging the battery more than 80% and the 44.8V=20% SoC figure given by BigBattery is most likely incorrect. Someone please check my math.

The big pack shows 46.8V to be the maximum charge voltage, so the whole battery maximum charge voltage must be (14/13)*46.8 = 50.4V, not the 51V BigBattery is claiming.

Edit:

The temperature range listed on the big pack is -30C to 55C. I have no idea how BigBattery came up with the -30C to 65C range.

I am still trying to figure out the SoC voltages.
 
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Greendream

Off-grid Beginner
My batteries will have a voltage of roughly 46.5 when in the middle of SOC. 43-44v still has a little juice though Ive not discharged below 43v, it starts tapering off fast below 44v.

49.6 to 46.5v is a relatively fast discharge.
46.5 to 44.0? is the plateau.
44 to 43v is relatively fast discharge again.

I have a magnum inverter with BMK I need a shunt to get some real numbers. My regular loads are about 8Ah.

When the day started batteries were at 45.2v. Now it's almost 11AM and only 47.2v. Magnum remote shows 100AH to batteries, total work time 4.5hrs, total harvest 4.7Kwh. So I'm guessing about 60AH back into batteries from the SCC.

With 3pc Llamas I have about 345AH @ 48V
 

Greendream

Off-grid Beginner
Do you have these connected in parallel? Do they play nice with each other?

Yes I have mine connected up to the bigbattery.com parallel box. The LED display seems to be a better measurement of amperage in or out from the parallel bank. They play well together however as I mentioned, one of the batteries BMS gets extremely hot and this particular battery usually is 0.2v less than the other two during the absorb phase, when they get to float they even out.

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anonymous

New Member
Nice.

It sucks that you have that issue with the BMS. Hopefully BigBattery can replace it for you.

Looks like you also have the issue with the current display on the batteries not showing the correct value.

Btw, I believe you can remount the anderson connectors to be deeper inside the battery so they don't stick out that much.
 

jmzorko

Solar Enthusiast
Yes I have mine connected up to the bigbattery.com parallel box. The LED display seems to be a better measurement of amperage in or out from the parallel bank. They play well together however as I mentioned, one of the batteries BMS gets extremely hot and this particular battery usually is 0.2v less than the other two during the absorb phase, when they get to float they even out.

View attachment 60168

I've got 4 LAMAs attached to my Sol-Ark 5k inverter. I agree that the amp indicator on the battery units themselves is often suspect, but the amp indicator on the parallel box seems more accurate. Currently my batteries are not doing much because the CTs for the Sol-Ark are installed in the wrong place, but this will hopefully be solved very soon. I also had questions about the SoC voltages, so this thread has been informative for me. I'm also interested in your continued experience with these batteries, so I can know what to expect once mine are actually providing power to the house. Many thanks for posting this!
 

Greendream

Off-grid Beginner
One of mine is for certain defective. Today I caught a glimpse of some smoke coming from the BMS. Not quite fast enough to get the smoke on video for their tech support. Worst smell in the world!

Still waiting on a reply from tech support for the next steps. Support is slow unfortunately. I will update as I make progress, or not.

I would definitely try and get them up and running. Nice batteries despite the issue I am having with the one.
 

jmzorko

Solar Enthusiast
One of mine is for certain defective. Today I caught a glimpse of some smoke coming from the BMS. Not quite fast enough to get the smoke on video for their tech support. Worst smell in the world!

Still waiting on a reply from tech support for the next steps. Support is slow unfortunately. I will update as I make progress, or not.

I would definitely try and get them up and running. Nice batteries despite the issue I am having with the one.
Oh they are connected, recognized by the Sol-Ark and technically "running". It's just that, until the current transformers are installed in the correct place, the inverter doesn't really use the batteries to any real degree (bc without the CTs, it doesn't know how much to draw from them). Once that is addressed (it looks like they need to be installed over the bussing connecting the utility side of the panel to the house side), they should provide accurate readings of the power my home draws from the grid. With that info, the inverter can start drawing that from the batteries instead. I'm waiting for the installer to do that.
 

Eddiebutch

New Member
big battery sent me a new llama top section box with all wiring and new prewired bms so i can replace my defective bms.
my Saturday afternoon project, will let you guys know how it turned out.
 

Greendream

Off-grid Beginner
I just requested an RMA on my battery. It would have been nice to have the top section only sent out but frankly I'm not 100% certain that's the issue (or only issue?). They said I need to ship it back via Freight, which I expect will take a week or so to get there, then they told me they will test it and send out a new battery even if they don't find any problems. That makes me feel a little better but I'm not happy to be on 2/3 capacity while I wait for the replacement.

I'll see if they would consider cross shipping if the plan is to just replace the battery anyway.

Updates as they come.
 

anonymous

New Member
By the way, I did a full discharge test and the battery I have seems to have the rated capacity.
 

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