Portable solar charger

[ExtremeX]

How much are you paying for the lithiums? And are they LiFePo chem or something else?

No, they are not LiFePO4 chemistry... You are probably referring to those large prismatic cells that are made in China. I found those to be pretty poor quality... Never get the advertised spec, not consistent, and when dealing with large battery banks often times run into balancing issues.

They still remain popular because the voltage fits well with people wanting a 12v system when used in a 4S configuration.

LiFePO4
Voltage nominal: 3.2V
Charge voltage cut-off: 3.6V
Discharging cut-off: 2.5V

The cells I have came out of a production EV, Fiat 500e. From what I read they are manufactured as a join venture between Bosch and Samsung. Pretty high quality stuff. So far in my testing the cells balance stays spot on with each other.

Per Cell:
Voltage nominal: 3.8 VDC
Charge voltage cut-off: 4.2VDC
Discharging cut-off: 3.0VDC

Per cell, pretty much in line with your typical 18650 lithium battery.

The OEM modules come in 5S and 6S configurations... you can break then down and make whatever you want but they are in a really nice welded chassis. Much easier to build them into something and secure as it so I am going to use them like that.

I am probably going to use it for home solar, but I might just make a whole house UPS first and skip out on the panels for now to keep costs down... basically a DIY Tesla Powerwall. Those inverters like higher voltages anyways, more efficient and smaller wire sizes... but right now I am just playing with them, learning about em, and doing some smaller DIYs before going big.

Price... you kinda have to buy the entire thing if you want a good price on them... PM me if you want more info.

Its only one module out of many that are in the car... here is what the entire battery array looks like. That's 24,000 watt hours of capacity... should be able to run my entire home.

[nathan4610]

We have used the 100ah square prismatic LiFePo4 cells with good results for electric vehicle applications. Not sure country of origin, they were white and sourced inside the US.

The reason those are popular is due to the charge voltage closely matching lead acid, you can use fairly dumb chargers and get an acceptable result as long as your not hitting them with high charge discharge rates.

As far as the ones you are sourcing, at the right price point i wouldnt care about the 4.2v per cell voltage. I have an Outback power systems setup on my house that runs 48v nominal and ive been trying to find a good source for replacement pack. I would need like 500ah 48v for my home. Its connected to a 5.2kw array.

Ill send you a PM.

[ExtremeX]

Yup, that's why I liked the LiFePO4 cells too... as long as your charger or alternator isn't really going above 14.4v there is little risk of problems or cell degradation.

Its still the most popular option for the RV guys that want conversions and are forced to stick with 12v applications.

Sounds like you know what types of hurdles are in front of you to use these types of cells... and that's a nice solar charge controller. I am planning on getting a Midnite solar Classic or MPPT Kid.