Recent content by sajjen

You did cells, not a battery. That is one of the reasons you are getting a better price. It is entirely possible, I would say even likely, that the cells are just out of balance, not deficient. When you buy cells, you need to have the equipment to handle cells. If you want a plug and play...

In general, a four cell BMS is not rated to disconnect a 24V load. If you are lucky, the output MOSFETs of the BMS will fail open, leaving you with an unusable battery. If you are less lucky, the MOSFETs will fail shorted, leaving you with no protection for your cells. Good thing you stayed...

For my capacity tests, I charged with 30A until 3.65V, no CV stage. Rest for 10 minutes, then discharge at 30A to 2.7V. Results varied between 145.5 and 150.7Ah. I've not done any further capacity tests since installing. In my application, a full cycle from full to empty will basically never...

And anyone not buying things for the first time will know to not trust a spec sheet until you have the product in hand and can verify it.

I bought the HiGee 150 Ah cells from BLS in about the same time frame. I did full capacity tests on each individual cell using a programmable PSU and an electronic load. That is in no way needed, but it did give me a lot of information. Most valuable to you would be that while all the 33 cells...

Your charge cut off voltage should be a function of the charge C rate. If you charge at 1C, a cutoff of 3.65V might be just fine. If charging at 0.15C, like you are, the limit should be lower. The 10A charge on a 200Ah pack would only be 0.05C. Cutoff should be lower still.

The BMV700-series meters from Victron have a serial port that could connect to an RPi.

GWL has been a leading distributor of LiFePO cells in Europe for about a decade. I bought my first set of Winston cells from them about ten years back. I've also bought CALB cells through them. In my experience, stock is fresh, packing is excellent, delivery and service is great. You get what...

There are plenty of reseller providing spacers, I'm not denying that. Fortune being one of them. I have never seen an actual cell manufacturer selling spacers. And as to the electrical isolation of cells. Just poke your multimeter probes through the plastic cover and measure to the terminals...

I've only seen spacers provided by resellers, never by cell manufacturers. But I can not prove a negative. Please show us where you've seen this. If your cells move around enough, relative to each other, to chafe the (very thin) plastic cover, I would say you've failed in securing the cells...

Yes, as you understand, it was meant to be worse than worst case scenario figures for the type of battery we're discussing. Aluminium case cells do not have the case electrically connected to any of the poles. There is no need to electrically isolate the cells from each other. Manufacturers of...

No one is claiming there is no heating of the cells, that would be ridiculous. Lets do some numbers: Assuming a 150Ah cell, 3.2V nominal, ca 480Wh Further assume a really poor cell with an internal resistance of 0.5mOhm Discharge the cell completely in one hour at a constant 1C load...

Är those loads I would not worry about cooling.

What kind of loads are you planning for? Until you reach high C rates, the cells don't heat up significantly.

How could you possibly claim that without testing the cells?