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Hello everyone,
So I have received my LifePO4 batteries and I can now make some observations rather then speculation. I do intent to make my own post and shw some charge curves but I wanted to follow up once on this thread in case people don't follow to the other one.
I want to speak to the balancing circuits again. I have tried charging up below the ceiling as I described and that method will work BUT you will not get the capacity out. When I did some charges to 14v I was only getting about 10AH out of a 20AH pack at a 5A rate down to 10.5v. That is done with a CBA. When I push all the way up I have pulled 19AH,, and 21AH a few times so it is important to push all the way up IF you need the full capacity. What I mean is you could under run them if you had enough cells to ensure you could meet your requirements but given the price of these cells it doesn't make sense to do that in my opinion. The thing that makes these cells special is that you can get more energy usage out of them safely, you can run them 80 percent or even more Dod making them stronger than their LA counterparts which really should only be brought down 50 percent or so. To put it another way you would need many more LA AH in your bank to get the same usage as with these.
Another observation is that the cells I am testing do not rise and fall so equally as I thought. One of them was reaching 3.8v well before the rest although standing they were all within a few hundredths of a volt. This presents another problem. once these cells reach saturation they do not pass current so imagine a middle cell reaching capacity before the rest, it will sit there and damage itself while simultaneously starving it's partner cell down the string because it passes little to no current. LA will just gas off but these shut off basically.
I am going to order some of the balance boards and see how that effects the charging, not sure if bedini tech will play nicely with them since these things are really meant to regulate high current and I am hitting them with spikes. If they are compatible I would say it is probably best to use them. As I have said you can run without them if your careful not to go to close to the top of the charge but personally I want the most capacity I can get out of these expensive cells and with the balancing circuits you probably don't have to babysit. For me it now hinges on whether or not feeding spikes through them is compatible.
Of course this is all experimental stuff, I'm sure it all works wonderfully with the new trackers. I am just experimenting with spike charging as a curiosity.
So I have received my LifePO4 batteries and I can now make some observations rather then speculation. I do intent to make my own post and shw some charge curves but I wanted to follow up once on this thread in case people don't follow to the other one.
I want to speak to the balancing circuits again. I have tried charging up below the ceiling as I described and that method will work BUT you will not get the capacity out. When I did some charges to 14v I was only getting about 10AH out of a 20AH pack at a 5A rate down to 10.5v. That is done with a CBA. When I push all the way up I have pulled 19AH,, and 21AH a few times so it is important to push all the way up IF you need the full capacity. What I mean is you could under run them if you had enough cells to ensure you could meet your requirements but given the price of these cells it doesn't make sense to do that in my opinion. The thing that makes these cells special is that you can get more energy usage out of them safely, you can run them 80 percent or even more Dod making them stronger than their LA counterparts which really should only be brought down 50 percent or so. To put it another way you would need many more LA AH in your bank to get the same usage as with these.
Another observation is that the cells I am testing do not rise and fall so equally as I thought. One of them was reaching 3.8v well before the rest although standing they were all within a few hundredths of a volt. This presents another problem. once these cells reach saturation they do not pass current so imagine a middle cell reaching capacity before the rest, it will sit there and damage itself while simultaneously starving it's partner cell down the string because it passes little to no current. LA will just gas off but these shut off basically.
I am going to order some of the balance boards and see how that effects the charging, not sure if bedini tech will play nicely with them since these things are really meant to regulate high current and I am hitting them with spikes. If they are compatible I would say it is probably best to use them. As I have said you can run without them if your careful not to go to close to the top of the charge but personally I want the most capacity I can get out of these expensive cells and with the balancing circuits you probably don't have to babysit. For me it now hinges on whether or not feeding spikes through them is compatible.
Of course this is all experimental stuff, I'm sure it all works wonderfully with the new trackers. I am just experimenting with spike charging as a curiosity.
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