10+ Best Geepower Three 2v Energy Power Storage
Always remember that the bottom capability cell is determines the capability of the bank. Do this so you know what you actually have for capability in every cell. Go a step past and arrange some exams so you realize the interior resistance of each cell too.
It isn't any problem to place a lithium-ion battery away for a year, just ensure there's some charge in it before inserting it in storage. Something between 50% – 60% is right, that will give the battery a very very long time before self-discharge brings the Voltage close to the hazard level.
With charge Voltages over 14.6 Volt actively discouraged, it ought to be clear that no equalize should be carried out to a lithium-ion battery! If equalize can't be disabled, set it to 14.6V or much less, so it turns into only a regular take in cost cycle. Shown in the graph is a cost rate of zero.5C, or half of the Ah capacity, in other words for a 100Ah battery this is able to be a cost price of fifty Amp. The cost Voltage is not going to actually change a lot for greater or lower cost charges , LFP batteries have a very flat Voltage curve.
The backside line is that we'd be comfortable to dimension a lithium-ion battery bank at 55% – 70% of the size of an equal lead-acid financial institution, and count on the identical (or better!) efficiency. Including on these darkish winter days when sun is briefly supply. Long lifespan, glorious discharge capability, appropriate for audio conversion, energy conversion, etc.
At 2000 cycles, to one hundred% DOD, these cells have been nonetheless placing up 35Ah’s or simply 5Ah’s shy of the as new capability ranking. A .4C charge price on a ship with a 400Ah LFP bank would be a cost price of 160A steady. This means an alternator with a 200A rating present limited to 160A. Most boats will battle simply to get to a .3C to .4C charge price.
On this pack the stored vitality between 3.4VPC and three.32VPC was 2.83Ah’s. This is the quite abrupt close to vertical portion of the blue voltage line at the very starting of the curve.
LFP batteries do not have to get again to 100% SOC with regularity like lead acid batteries do. Even should you only got to ninety five% and drained to 20% SOC you continue to get seventy five% usable capability and that is far larger than the 30-35% real world biking vary many cruisers get from lead acid. The cells on this image are cells which are nicely within the best steadiness vary when saved between 3.0VPC and three.55VPC. Once above three.55VPC these voltages diverge ever so slighlty.
The data is the same knowledge as the video beneath solely in a graphical format. Of fascinating notice is how little capability is saved above 3.32VPC, at loaded voltages, under a .075C discharge rate or 30A for a 400Ah rated pack.
At capacity test #12 (cycle #550) I switched this battery bank over to the DC digital load testers. All testing from this point forward has been be done utilizing these or our computerized testing station. The new baseline was established at cycle #550 and the financial institution delivered an 419.2 Ah’s, at a 30A fixed load, after 550 cycles down to three.0VPC. It’s type of tough to program an Ah counter whenever you actually do not know of the actual capacity other than what the producer tells you. Do yourself a favor and create a baseline Ah capacity for every of your cells.
If your pack is not built from properly matched cells and completely prime balanced, as this one was, you will note diverging voltages at even lower voltage ranges. Unfortunately drop-in batteries and most aftermarket BMS methods are designed for electrical automotive use and don’t at all times have the power to close charging down earlier than the BMS open-circuits the battery.