BYD LiFePo4 Packs Drama

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Joined
Oct 8, 2016
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There appears to be some drama with these batteries where Second Life Storage was selling the batteries for Big Battery. The batteries that were being shipped by Big Battery for Second Life Storage were "B" & "C" grade that were not testing near the 4-4.5 Kwh that was advertised. There is an active thread on DiySolarForumalong with videos byWill Prowse &DavidPozabout this issue and apparently Big Battery is issuing refunds if the batteries don't test correctly.

I need to get around to testing my batteries soon.
 

OffGridInTheCity

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BuffaloPowerWall said:
There appears to be some drama with these batteries where Second Life Storage was selling the batteries for Big Battery. The batteries that were being shipped by Big Battery for Second Life Storage were "B" & "C" grade that were not testing near the 4-4.5 Kwh that was advertised. There is an active thread on DiySolarForumalong with videos byWill Prowse &DavidPozabout this issue and apparently Big Battery is issuing refunds if the batteries don't test correctly.

I need to get around to testing my batteries soon.
@DIY Solar Power with Will Prowse did a youtube - "Used 5.6kWh LiFePO4 Solar Battery w/BMS for $850 (bigbattery.com)"
and explains (at6:05...) what he learned by talking to BatteryHookup and BigBattery - and suggests that you can see about returning them if you don't get the 4-4.5kwh.
 

hbpowerwall

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Yes, bit of drama around the battery it seams - but refunds & return shipping are being offered apparently.
 

not2bme

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Oct 16, 2017
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hbpowerwall said:
Yes, bit of drama around the battery it seams - but refunds & return shipping are being offered apparently.

WOw that's a bit of a understatement there. The batteryhookup was advertising 4-4.5kwh and claiming more. That's about 75-80% of the original 5.6kwh battery. But if people are seeing 3kwh like DavidPoz then it's less than 55% of original capacity. That's a big difference as it's not a linear scale where it goes down the same rate to 0%. At some point the battery will just deteriorate fast to 0%. So who knows you might see the dropoff at 40%, which means you have less lifetime capacity than you would have thought. Replacing those individual cells are almost impossible so if a cell goes bad it would be difficult. I wouldn't settle less than the advertised 4kwh!

You can see a demonstration from a member here that's been testing individual cells. The dropoff occurs rapidly once it starts.
https://secondlifestorage.com/showthread.php?tid=6868
 
Joined
Oct 8, 2016
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I am almost done testing my first pack and the results don't look promising. I currently don't have a 24v inverter, so the best dummy load I have is a few halogen work lights.


image_uoxunz.jpg
 
Joined
Oct 8, 2016
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I have finished the first round of testing for the first battery. I forgot to take a picture of the meter after the first discharge, but after recharging from 0% the battery took in 3.74 kWh, 143Ah.

I have a cheep 24v inverted coming so I can test the units a bit faster.


image_ayuaqm.jpg
 

floydR

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Aug 23, 2017
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My battery stopped discharging at 4 % not because it was out of power but because cell 1 or 4 hit the cut off point. AS the battery was well over 24v when the X8 shut it down. It produced 90AH from 26v to 25v, 7ah from 27.5v to 26v and 9 AH from 25v-24v for a total of 106 AH. around 2.5 kwh. What I don't understand is why the 27.5v to 26v only produced 7 AH. This time I will remember to take photos before and during.
possible causes:
Bad soldering job on the battery clamps
Cheap clamps very possible


image_gqxomz.jpg


The cells rebounded some i checked on the battery 15 minutes before and both cell 1 and 4 were very near the cut off of 2.85v
I will test my other battery tomorrow maybe then recheck this one.
later floyd
 

daromer

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IF you can hook it Up to the computer and log it. Then you Will see the grph om whats going on
 

daromer

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Logview is the name.
 

floydR

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Aug 23, 2017
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Thank you, I will get it later today. life has gotten in the way. my water heater decided to stop working over the weekend. Now I have to decide if i go with the NG tankless water heater I have on hand or fix it/get another 40 gallon (151 ltr) NG water heater.
Later floyd
106 AH 2.7 kh and 112 AH 2.8 kwh
 
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