Battery Design

[Ozi]

The other thing we need to consider is chemistry. The cells used in vehicle applications are high energy density and tend to be higher cost.

Grid applications are not concerned with weight or volume and hence are tending to use Lithium Iron Phosphate cells and these can have a much higher cycle life and are cheaper. This paper on slide 14 shows a cycle life of 12000 to 80% SoH: Degradation of Commercial Lithium-ion Cells Beyond 80% Capacity. (Conference) | OSTI.GOV

Thank you so much, it's something I believed was a good idea when I first heard about it but it's good to see it assessed by someone who knows rather than believes. The £4800 might be difficult to achieve as an installed price although I think these were going into new build which would help. It would not have to cover the full cost of the panels, assuming the panel life exceeds the battery life, additionally unless the cells being used in vehicles change radically (which may be very likely given the rate of development we are seeing) when the first set of cells expire they could then be replaced with the next set of used cells etc. which would presumably cost less than setting up the first time - no idea if this is being done.

 

[John Brown]

I had many years ago my grandfathers copy of an old UK book from around the 30's??? with many 'diy' electrical projects- one of which was a battery charger that plugged into a light socket, had a home made diode and used a lightbulb in series (they recommended a 15w from memory for most car batteries)
That was it- that was the entire circuit!!!
A diode and a light bulb in series, connected directly to the mains....
:-O

(in an unpolarised plug that fits into a BC lamp socket either way around...)

OHS would have kittens if they saw that these days lol

Lead acid batteries are almost infinitely abusable, compared with Lithium. When I was designing stuff, I would happily "design" charging circuitry for nickel batteries, but always used proprietary chips for Lithium.

 

[Dabop]

Lead acid batteries are almost infinitely abusable, compared with Lithium. When I was designing stuff, I would happily "design" charging circuitry for nickel batteries, but always used proprietary chips for Lithium.

Not so much the charging itself (but yes L/A can take a bit of abuse) but the fact that depending on which way around it was plugged, one battery clip could be connected directly to the mains Active!!!!
(even around the other way in the lamp fiting, you only had a relatively low resistance bulb filament between the Active and that clip- which in terms of electrocution, might as well not be there anyway)
:-O
Touch those leads while it is turned on and charging... well...
As the Mask says- 'Smokin'...

 

[Dabop]

It would not have to cover the full cost of the panels, assuming the panel life exceeds the battery life,

Short of physical damage, panels will outlast most of us actually posting here...

There's a lot of nonsense floating around the net (mostly coming from the US, which is notoriously antisolar) about short panel lifespans, with claims they won't last long enough to payback their cost...
(well the US does have insanely expensive solar compared to elsewhere lol- but not THAT expensive to make this claim true)
You will often hear 15, 20, 25 years as the lifespan of a panel- complete and utter (what comes out of the south end of a northbound male bovine...)

Any even half decent quality panel will have an 'output guarantee' which is usually 25 years at 80-90% depending on quality...
Many take this to mean that they last 25 years- which is nonsense...

What it means is that after 25 years, they guarantee to be still putting out MORE than the figure specified- in actuality, there are panels approaching the half century mark and still producing 60-70% or better!!!!
Indeed the very first set of panels I bought were in the early 80's, (1kw) and they are STILL in use at an ex neighbours and close to 70%...
My mothers set on the house for the gridtie (1997) are still well up over 80%, as are my uncles set (installed in 1999, on one of the Sydney Olympic houses built to house the athletes and sold of afterwards)- his are still up near 90%...

Panel life isn't likely to be an issue lol