Speak EV - Electric Car Forums banner

1 - 8 of 8 Posts

·
Registered
Joined
·
1,994 Posts
Discussion Starter #1
Hi all,

I'm moving from a 2 bed rented flat with solar heating to a bog standard 3 bed terrace (purchased).

I have been really impressed with the solar heating at the flat. It gets water to around 30 degrees c on the coldest of days.

Problem now is that I know little about energy generated from sunlight. I would lile to do something but not quite sure what... either with pv or heating.

Does anyone have any recomendations or experience either way? 100% pv? 50/50 pv/heating? Any schemes that are worthwhile?

Finding some kind of battery storage should be easy. I quite often perform lead to lithium upgrades for customers so having some used LA batteries in the loft should be doable

Budget not really considered at this stage but I can throw a couple of few thousand at this before I need to justify it. I'm happy to install myself to keep costs down

House is around 8m wide, about the same deep so I guess around 25/30sqm to play with either side of the roof (apex).

One side is south facing so that's a good start!
 

·
Registered
Joined
·
585 Posts
Lead acid batteries in the loft? Bad idea, very bad idea....

They weight a lot, the woodwork in an average loft is designed to keep the ceiling up and little more.
Lofts are baking hot in the summer, bad for batteries, freezing cold in the winter, bad for batteries.
Unless you're going to reinforce the trusses and insulate the upper sections (turning the loft from a cold roof to a warm roof), then it's a Very Bad Idea (tm).
 

·
Premium Member
Joined
·
1,579 Posts
Hmm, if you want to make it green then you will need to be clear about what you want to achieve. If you want to generate electricity and stay connected to the grid to earn the feed in tariff then you have to get an MCS approved installer to do the work. If you want solar thermal then you could self-install but can't claim the renewable heat incentive. Gaining MCS accreditation is costly and that is reflected in the premium you will pay for installation. Battery storage of electricity is very expensive and only makes sense in off-grid, low energy homes.

Many people who DIY install solar thermal use Navitron, who have a really informative forum. Whilst solar thermal appears very attractive (using the sun's energy to heat water) it's generally reckoned that diverting excess generation from solar PV to an immersion heater makes more sense economically. There are several devices which monitor solar PV and will automatically send excess production to the immersion heater.

Probably the best financial return you can achieve would be from increasing insulation and improving air tightness – sealing gaps around windows, doors, switches and sockets, and around pipes when they pass through walls, floors and ceilings. (An insulated house will lose half its heat through air leakage). Also consider an extra jacket on your water cylinder, lagging all hot water pipes, fitting eco shower heads and taps, LED lamps throughout and tighten up the controls on your heating.
 
  • Like
Reactions: Paul

·
Registered
Joined
·
1,994 Posts
Discussion Starter #5
@Paul Potterton Solar.

All, Thanks for the advice.

Insulation/air tightness will be done anyway.

I had similar thoughts on using pv for heating water. Probably more efficient to just heat electrically!?

Ideally I'd like to be able to charge the car from sunlight. When not charging the car energy either goes back to the grid or to storage (either as hot water or a battery bank).

Cost of batteries is not an issue as I often have used Lead Acid batteries which are no longer suitable for high current EV use but still hold energy. They currently just get scrapped (tried ebay before but usually sell just under scrap value).

For example I currently have 16KWH of 'scrap' trojan lead acid traction batteries sat in the workshop.

I understand issues with cold LA batteries but warm? Never experienced issues with LA getting too warm, especially trojans.

I'm thinking either to get on a scheme or just buy the kit myself and install?

Cheers,

Mike
 

·
Registered
Joined
·
585 Posts
@Paul Potterton Solar.
Ideally I'd like to be able to charge the car from sunlight. When not charging the car energy either goes back to the grid or to storage (either as hot water or a battery bank).
You'll want to get on the other thread about adapting a Rolec charger to charge slower, so it uses all (or a lot more) solar rather than grid electricity.

@PaulFor example I currently have 16KWH of 'scrap' trojan lead acid traction batteries sat in the workshop.
What kWh can they actually hold though?

@PaulI understand issues with cold LA batteries but warm? Never experienced issues with LA getting too warm, especially trojans.
Batteries like to be at a nice even temperature, but heating is best described here -
http://batteryuniversity.com/learn/article/how_heat_and_harsh_loading_reduces_battery_life
Good website with loads of info about all types of batteries...

Also, as Paul mentioned, what type of solar heating do you currently have?
 

·
Super Moderator
Joined
·
7,447 Posts
Worked out why our hot water system didn't ever work. No water in it. And if you introduce water, it pours through the bathroom ceiling from the "loft" space above. Hmmm.
Oh bugger! My house had sat empty (new build) for about 9 months before I moved in. The liquid in the solar system had evaporated or otherwise escaped, or at least enough to stop it working. Quick refill and it's worked a treat, think it's really smart! When I lived alone it created enough water for showering each day, but after the gf moved in the boiler has to go on in the morning too...!
 
1 - 8 of 8 Posts
Top