Home Battery update

  • 30 March 2024
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BPLightlog
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I’ve had solar panels for some time and added batteries more recently - which I’ve now added extra capacity to also. 
 

Over the last few weeks, I noticed a few changes to my inverter control options, the latest of which offered a ‘Battery Conditioning’ set up. 
Not knowing what this did exactly, I asked my installer but they were non the wiser, so I contacted the inverter manufacturer and got a mini manual update with a suggestion that this could help to extend battery life. 
Now having used it successfully, I thought it might be useful to pass on the information. 
There are different battery chemistries so you need to check your own set up but mine (and many others these days) use a Li-FePo4 (lithium iron phosphate) construction. With these batteries, especially when using multiple cells, it is important to keep battery voltages at the same level. 
The technique for calibration then works by charging the batteries to full (usually 100%) and then holding the charge at that level for a further hour. Once done, then a discharge sequence down to the set minimum (often 5%) allows the various cells to equalise and therefore enable a maximum level of charge to be achieved. 
I did this recently and can see my batteries achieving a higher voltage level than previously, more in line with their specification.

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3 replies

ChristopherS_OVO
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Hi @BPLightlog, 

This is such a useful insight into the world of batteries. This will be really useful for those with the a similar setup as you. It also will help increase the effectiveness of the batteries over a longer period. 

Keep us updated of your progress with this over the longer term. It’ll be interesting to see how this has impacted you over the next few months. 

 

waltyboy
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Hi @BPLightlog I’m never quite sure whether to charge my little LiFePo4 battery up to maximum voltage daily, so I charge only up to 28.9 Volts (rather than 29.0, or even 29.1).  Because I’ve only had it a year and it never discharges below around 30%, I haven’t yet noticed any failure in its performance.  
 

So do you think your inverter controls are responding to a software update, or perhaps are “remembering” the install date for your batteries, or do you think it’s something which hasn’t been that visible to you before now?

 

I must say I hadn’t realised about this conditioning business for lithium (as opposed to lead acid) batteries, so I was very interested…many thanks indeed…

Walt. 2013 installation 3.2kW PV East/West + Fronius IG, >23MWh (18MWh exported). 2023 2.4kWh LiFePo4 battery
BPLightlog
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Hi @waltyboy , it was prompted by an option appearing on my inverter web controls. So I began to investigate. 
The sequence I described is generally recommended when there are a number of battery modules in situ. In my case I have batteries from the first ‘addition’ and more recently, a couple of years later, further batteries added.

From what I understand, even in a battery module, the cells can become unbalanced and therefore occasionally need to be re-conditioned. Again, for me, I don’t believe that my additional batteries were balanced correctly when they were fitted, so my sequencing is just for now. In general times, I wouldn’t think that this was done more than 2 or 3 times per year. 
I began to do some testing as I couldn’t get full specified power despite the batteries being well charged. My voltage available has increased since the first conditioning sequence by 2.5v (to 51.5v). I think I can get another 1.5 to 2 volts with further sequencing 

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