Viewing 14 posts - 1 through 14 (of 14 total)
  • Solar battery owners
  • muddyjames
    Free Member

    Fox ess ones to be precise.

    What sort of current draw do these things sustain. Can you run the hob and oven together so could be 6kw I guess or more .

    igm
    Full Member

    Tesla PW can be bought as a 5kW / 13kWh unit, others will vary.  The kWh figure is important too if you’re doing things like cooking.

    How have you calculated the 6kW?
    If it’s just by adding each element the it’s Worth checking the diversified demand of your cooker, as ours was far less than I thought.

    The guide to the IEE wiring regs will help and your electrician will have that.

    There will also be a short term overload rating on the battery but I have no idea if that is published or how to calculate it.

    Daffy
    Full Member

    My new LG one when it gets installed in a month allows a continuous draw of 6kW, so would easily run the hob (0.9-1.5kW) oven (1.5-1.9kw) and even the kettle (2.93kw) dependent on what was being cooked. When it goes over the max, it takes the excess required from the grid.

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    MrTricky
    Free Member

    Would be very interested to know how much the various setups people have cost

    Daffy
    Full Member

    See The Solar Thread. There’s a few people who’ve listed prices.

    Flaperon
    Full Member

    Within reason the battery current is unlimited. The bottleneck is in the inverter, so if you only have a 3kW inverter, you can only pull 3kW from the battery, and so forth.

    More than 16A will require G99 approval from your DNO, which is a PITA at the moment. I’d accept that for heavy loads you’ll be using the grid.

    trail_rat
    Free Member

    Within reason the battery current is unlimited. The bottleneck is in the inverter, so if you only have a 3kW inverter, you can only pull 3kW from the battery, and so forth.

    Most life4po batteries dc linked I’ve seen are battery limited to 3kw regardless of inverter

    NMC Tesla quote 5kw

    muddyjames
    Free Member

    Hmm, thanks it’s the heavy loads that will be using the most juice and so will be what I want the solar to be powering…

    Plus when the apocalypse happens and the National grid goes down i want to be able to make pop corn as well as a cup of tea.

    If I have just shy of 6kw of panels does it follow that the inverter will cope with a load to that level.

    trail_rat
    Free Member

    How long are your heavy loads on for.

    I looked at my usage and other than the shower there’s very little drawing more than 3kw. So you just box clever. Even when the 4 rings of the hob and both ovens are on – once up to temperature they are rarely all on max all at same time….so just stagger turning them on by 5 minutes.

    Greybeard
    Free Member

    If I have just shy of 6kw of panels does it follow that the inverter will cope with a load to that level.

    That suggests you’re putting the battery on the DC side of the inverter for the panels. So if the grid goes down, unless your Fox ESS is the hybrid or all-in-one system (there doesn’t look to be a UK version of that) – see specs including output power here – it will cut out when the grid goes down.

    muddyjames
    Free Member

    Ah that’s no good. How is a battery grid side though- it’s dc surely. I’m totally ignorant on this technology I have to say.

    Greybeard
    Free Member

    Batteries can be on the AC side of your PV inverter, they then need their own transformer and inverter, which is less efficient, but usually easier to install. See here for comparisons. An AC battery also mean that if you get a grid tariff that varies over the day, you can buy your grid power cheap and store it until you need it. Historically, most PV in the UK has received FIT payments, which are based on what you generate, and putting a battery could complicate that. There are various standards and licencing rules which affect how you connect things that can feed the grid; there are others here who can explain them better than I can.

    PV systems are mostly set up to switch off if the grid goes down, otherwise they are feeding live power into the grid when people are trying to fix it. Tesla batteries have a cutout that isolates the house from the mains in that situation.

    trail_rat
    Free Member

    If you have fit payment linked to your install . You can’t retrofit a DC battery

    But there’s nothing stopping you charging a DC battery at off-peak rates .

    If you have stacked inverters it’s easier with an AC inverter.

    But otherwise it’s almost always better to have a DC linked one.

    There are a couple of islandable (automatic UPS) systems that are not just Tesla units these days. Likewise – there are many more than can be set up with a manual change over EPS

    Greybeard
    Free Member
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