wow!! that is impressive!!! will be very interesting to see how this setup serves your needs.
Today I am posting about a LifePO4 pack I have constructed and am testing. I share this stuff for the benifet of the group so that you can see what is out there and at least how one guy (myself) puts it together, along with some supplemental testing.
This pack is constructed of Tenergy 5.5AH LifePO4 cells. Here is a picture of a single cell:
The pack is constructed with a total of 40 cells. I made four banks of ten cells and put them in series. Here is a shot of the four strings assembled. I used welding rod for the bus bars, same kind as we use for coil cores. The plugs you see at the top are going across each cell pos and neg so that I can attach balancing boards which will be removable. I plan to build more of these packs and you only need the balance board while charging so I have made them detachable.
The next step I took was to hot glue some foam sheeting to the pack. This is to minimize any accidental knocking around of the pack and protect the buss bars a little.
To finish off the pack I wrapped it with hot tape. Here you can see the finished pack with the balance boards attached.
And just to see how it would go I hooked up my 400 watt inverter to the pack and charged another prismatic 20AH pack that I have. The charger is a 10 amp charger and everything ran fine, no heat on the batteries and the inverter and charger got slightly warm.
Finally here is a discharge curve from CBA testing. This was a 10A draw and I got 50AH from the pack. Technically it should be a 55AH pack but I'm impressed with how well it performed. Most real life loads are not going to be a constant current and probably not 10A but it shows that this thing does store some serious power.
Last edited by BobZilla; 01-22-2017 at 10:50 AM.
Last edited by BobZilla; 01-23-2017 at 09:32 PM.
Today I am showing this LifePO4 pack being used in bedini tech. Faraday didn't elaborate much with his statement but I think what he was trying to say is the same as I will say here now. Lithium batteries make awesome primaries for many reasons. One of the biggest reasons is that you get almost no voltage drop across a run. You can see this in the chart below. This run was approximately 28 hours at 1A and the primary hardly sagged at all.
The run was done on a SSR solid state mode one type of circuit. On the front we have the battery that this thread is about and on the back we had two garden batteries in series. These garden batteries were very depleted although you would not know it looking at their starting voltage. These batteries always bounce back up to a fairly high voltage no matter where I drag them down too, I think in part because of the radient charging they have received. I did not mention it in the video but I had actually run these down to about 9v by accident the night before with them as a primary in parallel. They had bounced back to around 12.2 from that and that is where they got setup for this charge.
Anyway here are the charts:
And a short video of the beginning and end of the run.
I am going to try and put this run through a few cycles and add to this thread. I kept the charge chart running and hooked up the CBA this morning to pull them down again. I am going to try to keep it all charting and pop another run on it. Don't know if I will be able to get it, something usually craps out with the meter or the computer over such long continuous attempts but if I can get it I will post back. I'm sure the next run on them will go faster because this time they will be cut off at 21v.
Hey I know you are working on similar builds with the 18650's, if you have the funds you might consider getting some of these and testing them out for yourself too. I have both cheap 18650's and some actual name brands (efest) which live up to their rating but since I got these lifePO4 cells I cannot see investing any more in the 18650's, these are just SO much better. Anyway I know you are on your own path and I respect that but I'm just saying these cells are winners for sure.
Guys the computer rebooted half way through the continuation of that run so I lost the charts. I thought it might happen but I am just following up because I said I might post more.