Inverter Battery Misconception.
Trust me, when anyone is trying to sell a product, they are at their best lying time 😂, not everyone though. A better way to put it would be that they are at their best time to sweet talk & over exaggerate the features of that product. This is not absent in the ‘Solar/Inverter’ (Renewable Energy) industry.
There are several components (equipment) that makes up an installation, and this is totally dependent on what the client wants.
- Inverter, Solar panels and Batteries
- Inverter and Batteries (very common)
- Inverter and Solar panels (more common for industrial clients)
The above ignores all the necessary accessories that makes up the full installation.
So we’d just focus on the misconceptions w.r.t #BATTERIES.
A typical RoadSyd Engr would tell U that the battery he’s abt to install would last U about 10hours b4 it goes low (when there’s no Grid and Solar Power).
NB: Each time there is Grid or U also have a solar panel as part of the installed equipment, the supposed ‘10hrs’ counter resets courtesy charging and discharging happening in a half-duplex mode.
Funny, the 10hrs can either be true or false, depending on the CONTEXT.
Quick Calc.:
Let’s say U’ve 4pcs of 12v 200Ah batteries (2-Series : 2-Parallel), that’s gives 2Px200Ah = 400Ah, and
2Sx12v = 24v
This means the TOTAL energy Ur Battery can give out is;
= 400Ah x 24v = 9600Wh (9.6kWh).
PS: Professionally, we call it ‘Energy Storage System’ rather than Battery 😎.
So, the only way ur Energy Storage System would last you 10hrs is if Ur load is 960W (0.96kW).
= 9.6kWh/0.96kW = 10hrs.
Context 1: The RoadSyd Engr did this calculation and got 10hrs: #TRUE
Context 2: Calculation wasn’t done: More likely to be #FALSE
Before we move to the next 2 contexts, we need to state certain facts.
- There are various kinds of Chemistry used for Energy Storage Systems (Battery). Lead Acid, Lithium ion, Lithium iron Phosphate, etc.
- Each of these Chemistries have several other variations. VRLA, AGM, Flooded, Lithium iron Phosphate etc.
- Most common Chemistry for residential batteries is Lead Acid (PbSO4).
- Most common Chemistry for industrial batteries is Lithium ion (Li+).
- Each of these Chemistries have a manufacturer’s recommended level of discharge (Depth of Discharge). Li+ = 100%, PbSO4 = 50%. This means for Li+ we can fully drain the entire 100%, while for PbSO4 we can only drain about 50% of its capacity. This doesn’t mean we can’t drain the remaining 50% for PbSO4, but we’re basically reducing the ‘Life Span of the battery by damaging the cell plate.
Now back to our contexts.
Context 3: The #battery chemistry used is Lithium ion. This means we can drain the entire 9.6kWh: #TRUE
Context 4: The battery chemistry used is Lead Acid. This means we can only drain 50% of 9.6kWh = 4.8kWh and for our 0.96kW load, this would last us 5hrs. : #FALSE
So we have 4 possible combinations of the contexts.
Contexts 1&3 = TRUE
Contexts 1&4 = FALSE
Contexts 2&3 = More likely TRUE & less likely FALSE
Contexts 2&4 = More likely FALSE & less likely TRUE
Don’t always trust that 10hrs the RoadSyd Engr tells U. 👩🏽🔧🧑🏾🔧👨🏽🔧