Domestic Batteries for on-grid solar 3

[Alistair_Heaton]

I don't have a problem with fla for stuff that they are good at. But the solar charging and discharge profiles don't really suit them.

Energy density is also an issue.

It's the amount of time and effort and tlc that the people who have relatively problem free time with them with solar go through.

They need to be almost a family pet, checked on, fed, pampered occasionally.

I have logged onto my BMS once in 3 years and 500 cycles.

I still think high currents play a large part in them dying quickly and heat. Mine max out put is 11 amps. Some of the DIY banks are pumping 200 amps plus with round circle losses over 30%. Mine is 4%.

The ones we tend to use in Europe are 100v plus voltage and set output current. So if you increase the capacity the voltage goes up. They say its more efficient if the voltage is above you single phase as voltage.

I think Tesla is 275V same as mine. But if I went for the max number of modules roughly the same capacity as a powerwall2 it would be over 550V. The powerwalls cause issues because they are over 16amps. And I don't like the no right or way to alter settings feature on them. Apparently they lock out if the internet drops out for a period of time.

 

[cranky108]

That would be a problem as the internet here goes out for almost every heavy rain or snow.

 

[Alistair_Heaton]

It's not instantaneous. Its 10 days plus or something like that. One of its features is power cut islanding.

I only know what you see in the solar groups. Wrong chemistry, way to expensive and no control over what it does was my issue so didn't progress to in depth feature research.

 

[hacksaw]

Flooded lead acid batteries go bad over time due to the lead particles building up under the plates, causing individual cell loss.

The acid itself doesn't go bad and can be reused.
Submarine, LA batteries have acid circulation pumps to pump the acid through coolers to reduce the temperature, back in the day.

Back in the day, the battery would be drained, with all the lead particulates, and quickly refilled with acid and recharged.
As long as the plates were more of less intact, the battery may have reduced capacity but still works.

Battery life is extended if overcharging is avoided.

The mesh pad designs, are not as robust. but more data is required.

 

[cranky108]

So you could get a longer life if the battery jar was deeper than the plates. Sort of wondered why the old battery jars were so deep. But I have never seen one working, just the jars at farm auctions.

 

[FreddyNurk]

I think they call them trash racks, where there is space at the bottom of the cell for the plate material that is shed during every cycle. Also noticeable when the material builds up it pushes the plate and terminals up and out of the casing. For this reason there's always some space allowed for in the terminal for growth.

A former employer had a nice cutaway profile of a battery that showed all the components, it was quite impressive.

EDMS Australia