VPP Grid Charging of Storage Batteries via Controlled Load or Off-Peak Power

[Richard]

Hi all,

AGL is very open to participants in the VPP using controlled load (off peak) to charge their batteries.  This could be particularly useful for people who have a heavy evening load, and require another heavy load for breakfast before their solar PV is able to charge their batteries again.  One thing to bear in mind when considering grid charging of batteries is that you may in effect be cycling your batteries twice a day.  These batteries have an approximate life of about 5000 charge/discharge cycles.  The reason they are warranted for ten years is because 365 x 10 is well within the estimated 5000 cycles.  If you do grid charge, you may double the cycle rate and degrade the batteries much more quickly.

Cheers,

Richard

Cheers,

Richard

[BWSS]

Hi Richard,

Can I ask were you read about the Sunverge batteries having a life of 5000 cycles, I was always lead to believe that those batteries had cycle based on the actual charge, like in if it charges say 50% owing to the weather then there is a part cycle to go.

I have a Holden/Chevy Volt and the batteries are in warranty for 8 years like all the electrics in the car, and the charge and discharge is not only based on the above but it gets it's warranty in the fact it's pre-programmed to charge to I think 80% and the same for a discharge, that reserve means it can never be fully charged or depleted thus adding to the life of the batteries.

I would imagine both batteries are of the same technology, the only missing factors neither the Volt or Sunverge have been aroung long enough to prove either way whether right or wrong.

I'm still a believer in use up all your solar during the day or as much as possible, whatever is over charges the batteries, my main interest in the batteries was no loss of power during a blackout which does mean to learn more about my usage so I can use as much during the day, including charging the car but having a good reserve for night use and blackouts.

Rob

[Richard]

Hi Rob,

I'll refer you, if I may, to an article I'm posting today on battery cycle life called "Lifespan of Solar Storage Batteries". 

Richard

[Bud]

Hi Richard,

Firstly, Thank you for all your informative posts.

Regarding your concern about "doubling the cycle rate",  the standard definition of a charge cycle is a full cycle using all the battery's capacity, but not necessarily by full charge and discharge. e.g. using 30%  of a fully charged battery, recharging it,  then using a further 40% and recharging again,  counts as 70% of a charge cycle.

By this definition, a charge cycle is dependent on real usage and not how often you recharge it.  Therefore using controlled load to top-up the battery wouldn't impact the number of cycles.

On the matter of "Grid Charging Storage Batteries via Controlled Load or Off-Peak Power" I specifically asked this question to the AGL consultant responsible for offering me a contract, and he replied that I couldn't use controlled load tariff for this purpose. His answer makes me suspect he doesn't know his product as well as he should.

Are you able to tell me if it is possible to have both the battery and hot water system on independent controlled-load switches or can you direct me to someone who would know this?

Cheers,

Bud

[Bud]

Hi again,

I have just come off the phone after a very extensive discussion with SAPN.  Although AGL may be open to participants in the VPP using controlled load (off peak) to charge their batteries, they are dependent on their provider who is SAPN, and SAPN policy is that controlled load tariff is NOT available for this purpose. Therefore the AGL consultant was correct. 

[szern]

I'm by no means an expert, but please take a look at Page 10:

https://www.aer.gov.au/system/files/AER approved - SA Power Networks 2017-18 Annual Pricing Proposal - 12 May 2017.pdf

Electric-Vehicle chargers are permitted to be connected to the OPCL circuit providing the charging equipment is not operating at more than 32 amps

Battery chargers are permitted to be temporarily connected to the OPCL circuit for the purpose of off-peak  charging  providing  they  are  disconnected  from  the  general  circuit  during  peak times. The battery can only be connected to either the general circuit or the OPCL circuit at any one time. The battery charger cannot operate at more than 32 amps.

Where multiple appliances are connected to a single phase of the OPCL circuit, eg hot water, EV batteries, battery storage and under-floor heating, only one appliance can operate at a time on that phase.

[shueardm1]

The answer is that your terminoligy is wrong. Controlled Load is incorrect, it should be "time of use load" and you would need a new meter to be installed at your cost.

This is what I found out anyway.

[NeilH]

Usually, the number of charge cycles during life of battery is dependent on DoD, depth of discharge, when being charged.  The lower the DoD, higher the retained charge, when the battery is recharged the more charges or longer life span of battery.