You'll want to put some kind of meter in your installation. The Victron Smart Shunt is a popular choice in the RV industry, although it is much more expensive than other options. You need a device that has a coulomb counter, i.e. it keeps a tally of amp hours and/or watt hours. That way, you can tell if those cells still have 280 amp hours. I suspect you've lost a good chunk of their capacity by overcharging them, but some percentage will still be usable.
You might want to read the data sheet on these LiFePO4 batteries, they are designed to be changed to 3.65V, slight swelling is normal. Compression is optional, but needs to be done before charging. They have a very flat charging curve, charging to 3.2V is too little, should be charged to 3.45v for 100%.
I should have been clearer in my description, the target voltage was set to 3.64V. I did have a browse through the data sheet, but I'll go back and have a better read of it. Cheers!
Well done mate for persevering. I can really relate to that saying too. The two downsides of that, is time spent and money spent along the way. I’m doing the same thing changing thing’s numerous time. Hopefully for the better 😅
Keep a bag of marshmallows right by the door. Jokes aside LFP batteries have a very low risk of fire, they can be submerged in water, punctured, overcharged and all kinds of other punishment without catching fire, there's plenty of videos on UA-cam about it. Lithium Ion batteries have the biggest fire risk, it's often an electric device with a lithium ion battery on charge that starts a fire. Once these packs are connected, the BMS will prevent them from being overcharged
So what gave you the idea that it’s ok to compress bulged cells? Extremely likely that the burst disk will let go sooner or later under a normal full charge of 3.45VPC. 4.6 Volts? Compromised. If you compress, you do it from the start and that includes top balance. If you must unclamp you do it at a low state of charge and when they are cool.
The tiny little evil red man on my left shoulder. I've charged them back up to 3.46, I guess I won't know the damage until I've installed them and hooked them up. Do you know the correct N m they need to be compressed to?
@@dancampion I don’t use rigid/fixed compression. I use springs because the cells can expand a bit even with compression. Area of side of cell 174x205 mm =55.288 square inches of area. 12 psi max optimal. 10 psi safe so 55X 10=550 psi so divided by 4 = 137lbs spring per bolt or for a two bolt compression 274 lbs spring per bolt. Die springs work. You select the springs based on size, spring pressure at it’s rated compressed height. For mobile you absolutely must have electrical separators between cells,under and side so they don’t rub through. Any place things could short probably will if you don’t get that critter off your shoulder. Good luck, I hope you didn’t kill those cells.
This is very interesting. I admire your determination. But i have done worries too. There are many things i have done different compared to you. I built 2 lfp batteries after many, many hours of learning. I am no expert, but i do see some risks. Your working environment is not clean. Damaging the foil on these cells is a risk. Charging your batteries and discharging them is described in their datasheet. The bms you are about to use may not be the best choise imho Balancing starts at 3.45 volts. If you intend to make good use of your batteries for years, you really should dive in to this material yourself . Your health is at risk. There is a huge amount of energy in one single cell. A short always comes as a surprise.
Thank you, I should have been clearer, I did set the target voltage to 3.64 for balancing. Hahah yes I couldn't agree more about the work area, it is a problem, no doubt it points to some deeper issues. I'm also no expert, but I have a certified electrician guiding me who builds these systems, and I trust his guidance
Those cells dont look bad at all. You should be fine
You'll want to put some kind of meter in your installation. The Victron Smart Shunt is a popular choice in the RV industry, although it is much more expensive than other options. You need a device that has a coulomb counter, i.e. it keeps a tally of amp hours and/or watt hours. That way, you can tell if those cells still have 280 amp hours. I suspect you've lost a good chunk of their capacity by overcharging them, but some percentage will still be usable.
You might want to read the data sheet on these LiFePO4 batteries, they are designed to be changed to 3.65V, slight swelling is normal. Compression is optional, but needs to be done before charging. They have a very flat charging curve, charging to 3.2V is too little, should be charged to 3.45v for 100%.
I should have been clearer in my description, the target voltage was set to 3.64V. I did have a browse through the data sheet, but I'll go back and have a better read of it. Cheers!
Your levels of motivation and determination are astonishing!
Well done mate for persevering. I can really relate to that saying too. The two downsides of that, is time spent and money spent along the way. I’m doing the same thing changing thing’s numerous time. Hopefully for the better 😅
👍👍
👍👍👍👍👍👍👍
👍
baba booey....
What's your fire plan?
Keep a bag of marshmallows right by the door.
Jokes aside LFP batteries have a very low risk of fire, they can be submerged in water, punctured, overcharged and all kinds of other punishment without catching fire, there's plenty of videos on UA-cam about it. Lithium Ion batteries have the biggest fire risk, it's often an electric device with a lithium ion battery on charge that starts a fire. Once these packs are connected, the BMS will prevent them from being overcharged
So what gave you the idea that it’s ok to compress bulged cells? Extremely likely that the burst disk will let go sooner or later under a normal full charge of 3.45VPC. 4.6 Volts? Compromised. If you compress, you do it from the start and that includes top balance. If you must unclamp you do it at a low state of charge and when they are cool.
The tiny little evil red man on my left shoulder. I've charged them back up to 3.46, I guess I won't know the damage until I've installed them and hooked them up. Do you know the correct N m they need to be compressed to?
@@dancampion
I don’t use rigid/fixed compression. I use springs because the cells can expand a bit even with compression. Area of side of cell 174x205 mm =55.288 square inches of area. 12 psi max optimal. 10 psi safe so 55X 10=550 psi so divided by 4 = 137lbs spring per bolt or for a two bolt compression 274 lbs spring per bolt.
Die springs work. You select the springs based on size, spring pressure at it’s rated compressed height. For mobile you absolutely must have electrical separators between cells,under and side so they don’t rub through. Any place things could short probably will if you don’t get that critter off your shoulder. Good luck, I hope you didn’t kill those cells.
Is there a BMS connected to each cell?
Yeah there is
This is very interesting. I admire your determination. But i have done worries too. There are many things i have done different compared to you. I built 2 lfp batteries after many, many hours of learning.
I am no expert, but i do see some risks.
Your working environment is not clean. Damaging the foil on these cells is a risk.
Charging your batteries and discharging them is described in their datasheet.
The bms you are about to use may not be the best choise imho
Balancing starts at 3.45 volts.
If you intend to make good use of your batteries for years, you really should dive in to this material yourself . Your health is at risk. There is a huge amount of energy in one single cell. A short always comes as a surprise.
Thank you, I should have been clearer, I did set the target voltage to 3.64 for balancing. Hahah yes I couldn't agree more about the work area, it is a problem, no doubt it points to some deeper issues. I'm also no expert, but I have a certified electrician guiding me who builds these systems, and I trust his guidance
And I appreciate your feedback! Thanks for watching and for caring enough to give me some feedback
Stop abusing this poor batteries. First you whip them with over 4V and next you bondage them strong, as the goes flat. OMG!