Portable batteries worth considering?

In my mind the answer is no but just wanted to confirm this.

If I was to buy a portable power station for my fish tank, and have it charge when I only had excess solar, low import or the battery reaches 10% would the savings actually be worthwhile or is it essentially pointless? The fishtank uses a little over 1kwh a day. 
4.29kWp Solar system, 45/55 South/West split in cloudy rainy Cumbria. 
«1

Comments

  • Netexporter
    Netexporter Posts: 1,016
    First Post Name Dropper
    Forumite
    Divide the cost of the battery by 6000 and see how that compared to the cost of a unit of electricity.
  • Spies
    Spies Posts: 1,935
    First Post Photogenic First Anniversary Name Dropper
    Forumite
    Is that 6000 based on cycles before 80% capacity? 
    4.29kWp Solar system, 45/55 South/West split in cloudy rainy Cumbria. 
  • Netexporter
    Netexporter Posts: 1,016
    First Post Name Dropper
    Forumite
    Doesn't really matter. It'll give a quick ballpark figure to see whether it is worth going into more detail.
  • Spies
    Spies Posts: 1,935
    First Post Photogenic First Anniversary Name Dropper
    Forumite
    edited 6 October 2023 at 6:09PM
    0.0365p for a 256wh battery...

    Or 0.18p for a 1024wh battery

    I don't really get the 6000, because the smaller the capacity the more favourable it seems, if you could tell me why 6000 I would appreciate it
    4.29kWp Solar system, 45/55 South/West split in cloudy rainy Cumbria. 
  • Netexporter
    Netexporter Posts: 1,016
    First Post Name Dropper
    Forumite
    Most lithium batteries are guaranteed for 6000 cycles. They'll probably last longer but it's a good a number as any to use.

    You'd need two of the larger batteries, one in use and one charging. Would you need any other gear, apart from the charger, or will the aquarium kit run directly off the battery?
  • QrizB
    QrizB Posts: 13,615
    First Post First Anniversary Photogenic Name Dropper
    Forumite
    Spies said:
    0.0365p for a 256wh battery...
    Or 0.18p for a 1024wh battery
    I don't think you've done the correct sums!
    Here's a Jackery (big brand) portable power station. 240Wh, £260. £260/6000 = 4.3p. So you'll be paying 4.3p per battery cycle (0r 4.3 / 0.24 = 18p per kWh), plus the cost of the power itself.
    Here's a bigger Jackery. 1264Wh, £1149. That's 19.15p per cycle (15p per kWh).
    Or, for comparison, here is a Solis hybrid inverter plus 2x2.4kWh Pylontech batteries. 4.8kWh, £2765. £2765/6000 = 46p per cycle, 9.6p per kWh.
    N. Hampshire, he/him. Octopus Go elec & Tracker gas / Shell BB / Lyca mobi. Ripple Kirk Hill member.
    2.72kWp PV facing SSW installed Jan 2012. 11 x 247w panels, 3.6kw inverter. 30MWh generated, long-term average 2.6 Os.
    Ofgem cap table, Ofgem cap explainer. Economy 7 cap explainer. Gas vs E7 vs peak elec heating costs.
  • badmemory
    badmemory Posts: 7,485
    First Anniversary Name Dropper First Post
    Forumite
    Surely some of this depends on the value of the fish in the aquarium.  Last time I had one we had discus at £40 a piece (over 30 years ago) until they became a breeding pair after that the sky is the limit.  Well until a flash of lightening & they ate the lot.  If we had fish now that needed keeping up to temp with regular powercuts, well you do what you need to do if they have value to you.
  • Spies
    Spies Posts: 1,935
    First Post Photogenic First Anniversary Name Dropper
    Forumite
    QrizB said:
    Spies said:
    0.0365p for a 256wh battery...
    Or 0.18p for a 1024wh battery
    I don't think you've done the correct sums!
    Here's a Jackery (big brand) portable power station. 240Wh, £260. £260/6000 = 4.3p. So you'll be paying 4.3p per battery cycle (0r 4.3 / 0.24 = 18p per kWh), plus the cost of the power itself.
    Here's a bigger Jackery. 1264Wh, £1149. That's 19.15p per cycle (15p per kWh).
    Or, for comparison, here is a Solis hybrid inverter plus 2x2.4kWh Pylontech batteries. 4.8kWh, £2765. £2765/6000 = 46p per cycle, 9.6p per kWh.
    So from the point of view of saving money by running things from a power station is basically a waste of time if you're being paid for export
    4.29kWp Solar system, 45/55 South/West split in cloudy rainy Cumbria. 
  • QrizB
    QrizB Posts: 13,615
    First Post First Anniversary Photogenic Name Dropper
    Forumite
    Spies said:
    QrizB said:
    Spies said:
    0.0365p for a 256wh battery...
    Or 0.18p for a 1024wh battery
    I don't think you've done the correct sums!
    Here's a Jackery (big brand) portable power station. 240Wh, £260. £260/6000 = 4.3p. So you'll be paying 4.3p per battery cycle (0r 4.3 / 0.24 = 18p per kWh), plus the cost of the power itself.
    Here's a bigger Jackery. 1264Wh, £1149. That's 19.15p per cycle (15p per kWh).
    Or, for comparison, here is a Solis hybrid inverter plus 2x2.4kWh Pylontech batteries. 4.8kWh, £2765. £2765/6000 = 46p per cycle, 9.6p per kWh.
    So from the point of view of saving money by running things from a power station is basically a waste of time if you're being paid for export
    It depends on the difference between import cost and export payment, but yes, if you can buy power from the grid for eg. 10p/kWh more than you get for export, batteries are unlikely to save money.
    Bear in mind that, prior to about 12 months ago, Octopus Outgoing Fixed was one of the better export tariffs at 5p/kWh. It's only recently that 15p/kWh export payments have become available.

    N. Hampshire, he/him. Octopus Go elec & Tracker gas / Shell BB / Lyca mobi. Ripple Kirk Hill member.
    2.72kWp PV facing SSW installed Jan 2012. 11 x 247w panels, 3.6kw inverter. 30MWh generated, long-term average 2.6 Os.
    Ofgem cap table, Ofgem cap explainer. Economy 7 cap explainer. Gas vs E7 vs peak elec heating costs.
  • paul991
    paul991 Posts: 348
    First Anniversary First Post
    Forumite
    but if you charge your battery cheaply to self consume your saving your self 21 pence kw ie  between economy 7 and peak time but the main use of portable power packs is to be able to keep power on if essential
Meet your Ambassadors

Categories

  • All Categories
  • 341.6K Banking & Borrowing
  • 249.7K Reduce Debt & Boost Income
  • 449.1K Spending & Discounts
  • 233.7K Work, Benefits & Business
  • 605.7K Mortgages, Homes & Bills
  • 172.4K Life & Family
  • 246.6K Travel & Transport
  • 1.5M Hobbies & Leisure
  • 15.8K Discuss & Feedback
  • 15.1K Coronavirus Support Boards