Discharge current 48v 280ah?

bushi12

Solar Enthusiast
Screenshot_20211020-222213_Remote Desktop.jpg
This is what the tester recommended. This is gonna take about 80 more hours if I figured right. Is this okay?
 

Short_Shot

Photon Sorcerer
Its fine as long as you can wait the 80 hrs.
The CBA battery analyzer is limited on how much wattage it can handle.

Unfortunately that's pretty much all you get.

If you had another known, fixed load you could apply that and do the math to speed it up.

For a higher current test with your pack I would say (for example) put 9a on another load and 3a on the cba, total 12a.

Then just multiply the result from the CBA by 4 to get the tested capacity.

You could go much higher on the auxiliary load though as long as youre able to and you don't need to go that simple on the ratio.

Like 3a on the cba and 50a on the auxiliary load gives you 53a actual, so you'd multiply the cba ah result by 17.666....
Only really works as long as you keep the auxiliary load constant of course.


However if this is for warranty purposes with a Chinese seller unfortunately they only accept results if they are done per-cell.
 

bushi12

Solar Enthusiast
Its fine as long as you can wait the 80 hrs.
The CBA battery analyzer is limited on how much wattage it can handle.

Unfortunately that's pretty much all you get.

If you had another known, fixed load you could apply that and do the math to speed it up.

For a higher current test with your pack I would say (for example) put 9a on another load and 3a on the cba, total 12a.

Then just multiply the result from the CBA by 4 to get the tested capacity.

You could go much higher on the auxiliary load though as long as youre able to and you don't need to go that simple on the ratio.

Like 3a on the cba and 50a on the auxiliary load gives you 53a actual, so you'd multiply the cba ah result by 17.666....
Only really works as long as you keep the auxiliary load constant of course.


However if this is for warranty purposes with a Chinese seller unfortunately they only accept results if they are done per-cell.
Okay this isn't for warranty. Just personal knowledge. I can set the discharge to whatever I want. As long as the cba will handle it. I don't know discharge rates. This is my first time building a system.
 

Short_Shot

Photon Sorcerer
Okay this isn't for warranty. Just personal knowledge. I can set the discharge to whatever I want. As long as the cba will handle it. I don't know discharge rates. This is my first time building a system.

You're good then. Just a waiting game. While you can "set it to whatever you want" it can't handle much more wattage than that. Even that's pushing it tbh.
 

bushi12

Solar Enthusiast
280Ah / 3.18A = 88h

The tester recommended 3.18A?

3.18A x (16 x 3.2V) = 162.8W
When I was putting in the information for the batteries it auto filled the the 3.18. I could change it but didn't know to what. I put 23 and it said it was too high and suggested a amplifier. I got the West Mountain Radio CBA V Pro 100v. I'm still learning all this amp/volts/watts. I have 4 other 16s packs to do. What would you recommend.
 

bushi12

Solar Enthusiast
You're good then. Just a waiting game. While you can "set it to whatever you want" it can't handle much more wattage than that. Even that's pushing it tbh.
Okay thanks. I figured I would be able to do it faster. I got the CBA V Pro 100v. The 500 amplifier from them was more than I wanted to spend.
 

bushi12

Solar Enthusiast
Ah. That might be a bit higher wattage limit than my IV. You'd have to check the spec.
The specs say my max discharge rate is 40amp. Discharge range is 1-200w. That's why I was confused when it recommended 3.18 and wouldn't accept 23 without a amplifier.
 

Short_Shot

Photon Sorcerer
The specs say my max discharge rate is 40amp. Discharge range is 1-200w. That's why I was confused when it recommended 3.18 and wouldn't accept 23 without a amplifier.
Well. For 51v 200w is 3.9a ish. It might vary a bit depending on voltage too.

My IV is limited to less wattage with lower voltage.
 

RCinFLA

Photon Sorcerer
Depends on what you are trying to check for but this is not a very effective test on a 280 AH cell.

Beside just capacity, the ability to deliver moderate current is an important consideration. For cells that may be used, the ability to deliver respectable current level is a strong indication of condition of cell. As cells age their overpotential terminal voltage drop with load increases. This increases cell internal losses and greatly decreases their ability to deliver capacity at moderate load.

You should try to load cell with 0.2 CA to 0.4 CA to evaluate the amount of terminal voltage slump occurs. The more the terminal voltage slump at these current rates the less the likelyhood it will be able to deliver rated capacity. Just because it delivers a respectable capacity at low load current does not make it a usable cell.
 

bushi12

Solar Enthusiast
Well. For 51v 200w is 3.9a ish. It might vary a bit depending on voltage too.

My IV is limited to less wattage with lower voltage.
On the next set I could break it down to 8s24v I have a bms for that. I could get more amps that way about 8 if I'm doing it right.
 

bushi12

Solar Enthusiast
Depends on what you are trying to check for but this is not a very effective test on a 280 AH cell.

Beside just capacity, the ability to deliver moderate current is an important consideration. For cells that may be used, the ability to deliver respectable current level is a strong indication of condition of cell. As cells age their overpotential terminal voltage drop with load increases. This increases cell internal losses and greatly decreases their ability to deliver capacity at moderate load.

You should try to load cell with 0.2 CA to 0.4 CA to evaluate the amount of terminal voltage slump occurs. The more the terminal voltage slump at these current rates the less the likelyhood it will be able to deliver rated capacity. Just because it delivers a respectable capacity at low load current does not make it a usable cell.
I'm sorry but I have no idea what your trying to explain. I appreciate it but this is my first time building a system with no experience. I will try whatever I need to. I just need to understand it. .2 to .4 ca means what and how do I do it?
 

RCinFLA

Photon Sorcerer
I'm sorry but I have no idea what your trying to explain. I appreciate it but this is my first time building a system with no experience. I will try whatever I need to. I just need to understand it. .2 to .4 ca means what and how do I do it?
It means a load current of 0.2 to 0.4 times the 280 AH battery capacity in amps. 56 amps to 112 amps of load current.
 

Short_Shot

Photon Sorcerer
Depends on what you are trying to check for but this is not a very effective test on a 280 AH cell.

Beside just capacity, the ability to deliver moderate current is an important consideration. For cells that may be used, the ability to deliver respectable current level is a strong indication of condition of cell. As cells age their overpotential terminal voltage drop with load increases. This increases cell internal losses and greatly decreases their ability to deliver capacity at moderate load.

You should try to load cell with 0.2 CA to 0.4 CA to evaluate the amount of terminal voltage slump occurs. The more the terminal voltage slump at these current rates the less the likelyhood it will be able to deliver rated capacity. Just because it delivers a respectable capacity at low load current does not make it a usable cell.
...CA?


Most lifepo4 is good to 1C. Not sure what the CA is and your .2 to .4 is a lead thing.

Getting 0.2c from 280ah with the limited test equipment isn't really easy.

I agree with the overall point though
 
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