Batteries for proper off-griddedness.

[Crofter]

12 hours ago, SteamyTea said:

How well do they cope if they get in contact with seawater?

I seem to remember that lithium, sodium and chlorine can quickly become a mess, but then I am not a chemist.

As I understand it there is no elemental lithium involved, just ions. So in that respect you could worry just as much about the seawater itself.

[Crofter]

9 hours ago, DamonHD said:

 

Come and have a read over at fieldlines.com where people do indeed play a little fast and loose, but without generally setting fire to anything.

 

However, you aren't going to want to build an inter-seasonal store out of Li batteries to carry energy into the winter when you're cold because there's less solar insolation...

 

I priced up an (optimistic, no-space-heat, Vanadium redox) interseasonal battery for my house which is quite low use, and it was something like £250k and sould have needed a basement dug for it.  Note that we generate enough from PV to cover all our electricity (and space-heat with heat pump) use over a year, ie we're already net zero on that.

 

Rgds

 

Damon

 

Well yes there's a bit of a difference between storing enough energy for a day, and enough for a winter!

Maybe a bit more wind power would be a better idea than trying to get through a whole year on PV alone...?

[MarkH]

On 17/11/2020 at 18:49, MarkH said:

Just to update this - a few years down the line. My 345ah@48V flooded lead acid bank has done the job for over 5 years now but a very busy recent work period and various other factors have contributed to some shoddy maintenance and FLA doesn't like that. They need tending and every bit of neglect takes it's toll. Anyway - the bank of twelve 115ah FLAs is now a bank of eight battered, prematurely aged sulphated hulks. 

 

I'm probably going with lithium - Pylontech. The price has come down, the warranties are long, they play well with Victron kit and will do what they're supposed to without me having to mess around with sulphuric acid once a month. 

Just to re-update this -  a few more years down the line!

 

I went with Pylontech US3000 Lithium units, initially 3 of them and then added 2 more. They are absolutely great - zero maintenance, zero hassle. With a 6kw PV bank I'm sorted for the vast majority of the year with a generator being required for a top-up 6 times this winter. I expect that when I get round to moving the PV array to the roof and doubling it's size I won't need the gen at all.

 

I'd have no need for the generator if I hadn't ditched my wind-turbine but I don't miss that howling beast when it's windy (there was no easy way of making it play with lithium/Victron).

 

My time with flooded lead acid batteries was educational but I do not miss it! Less of my clothing has small acid burns and the monthly maintenance schedule has become an occasional glance at the Victron App. 

 

 

Edited April 3, 2023 by MarkH
missed a bit

[SteamyTea]

1 hour ago, MarkH said:

I'd have no need for the generator if I hadn't ditched my wind-turbine but I don't miss that howling beast when it's windy (there was no easy way of making it play with lithium/Victron).

Could you not have had the turbine (I assume it was small) dedicated to just heating water, then no need to control much at all, just maximum temperature.

[MarkH]

6 hours ago, SteamyTea said:

Could you not have had the turbine (I assume it was small) dedicated to just heating water, then no need to control much at all, just maximum temperature.

Absolutely. But it would still have been a noisy pain in the arse! It was an LE-600 with a nominal 750W max output. 

 

I'd have a turbine in the future, but I'd want it to be much further away from the house (100m at least) to cut the noise down. 

[SteamyTea]

55 minutes ago, MarkH said:

But it would still have been a noisy pain in the arse

I worked, briefly, for a small turbine manufacturer. They made a 5 kW turbine.

It was a bit noisy if you were downwind of it.

I did think up a way to significantly reduce and deflect the noise, but never got a chance to test it. Company ceased trading, then the design got bought off the receiver.

Luckily I had not left my ideas with them.

[MarkH]

Partly due to it's size (not so big) and partly due to the unclean airflow from anything except the South my turbine was pretty loud. The house is massively insulated and triple glazed but the turbine noise was quite un-enjoyable during any significant wind. I'm glad it's gone.

 

[Nickfromwales]

5 hours ago, MarkH said:

Partly due to it's size (not so big) and partly due to the unclean airflow from anything except the South my turbine was pretty loud. The house is massively insulated and triple glazed but the turbine noise was quite un-enjoyable during any significant wind. I'm glad it's gone.

 

I was considering a small vertical axis turbine, say 1kW, and hoping they aren't as problematic ( at that size, and that type ). More as a toy, than to provide for my needs, but it would be good to have any little trickle-charge at night.

[MarkH]

10 hours ago, Nickfromwales said:

I was considering a small vertical axis turbine, say 1kW, and hoping they aren't as problematic ( at that size, and that type ). More as a toy, than to provide for my needs, but it would be good to have any little trickle-charge at night.

 

Completely worthwhile as a toy! I think the best use of a turbine is just steadily contributing energy to a hot water tank - no batteries needed, simple set-up, cheap... Ideal. But only if it's quiet, low maintenance and looks after itself in a gale.

[Nickfromwales]

6 hours ago, MarkH said:

and looks after itself in a gale.

I can always ask the next door neighbour to fetch it back.