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KWH Comparison Table


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I doubt it, since that would depend...

what E-Skom/Municipal rates are you paying etc. also what your actual power needs are, which would determine how large a setup you'd require etc.

What is 100% true right now, is that E-Skom is the cheapest battery, but that's total BS, since when that battery is dead (rollling thingymajigs) then the cost doesn't really matter, after all the cheapest car that doesn't run is just a pile of scrap metal with more value than Eksdom when they're down.

So, going solar/wind/wave/whatever else energy is not necessarily for everyone. Solar is the least expensive assuming you've got plenty of sunshine all year round. Wind, where I am, is useless, not enough or regularly enough. Your location may differ, but I'd see wind as a (hopeful) backup (assuming it can add energy overnight when there's no solar) in which case, it probably does not need to add more than a steady kW or so.

If you won't be grid tied and need to rely on renewable energy, you will most likely time shift some of your consumption behaviour, we, for instance, run the dishwasher around midday when there's more than plenty to go around, but, on a cloudy day, skip it entirely.

Basically get ideally a hybrid inverter that has more capacity than you need, if its a Sunsynk, for instance, this can expand by running more than one in parallel if your consumption needs rise significantly, but this, obviously also will increase the power source requirements (more solar panels etc.) and battery storage requirements.

Solar panels (most likely) get what your peak consumption is likely to be, this will give you more energy than what you know what to do with and leaves room for energy consumption expansion.

Battery capacity, if you're Rockefeller or a close family member you can look at boatloads of 1000Ah 2V Lead Acid cells else you're probably looking at LiFePO4's, you should, if you want a longish life out of these, again, I'd think so, unless you have money to burn, work out what consumption you need for when you have no primary (solar panel) power production and assuming no wind power production and in the case of LiFePO4's probably add 40% to the energy budget, so if you need 10kWh for the hours where no other energy is being produced/procured from elsewhere, you should look at 14kWh of battery capacity.

Wind energy, can't help you there, if we had enough, I'd cobble something together myself, but no wind mostly, or at least nothing of value.

Lead acid batteries, opinions differ and some may even claim that you can use 50% or more of these batteries' capacity, which is true, *but* if you do, you probably will not have use of these for even 5 years, probably more likely 2 to 3 years. Lead acid batteries should probably not be expected to exceed more than 20% maximum of their rated capacity and then only for an hour, which means, if its a 100Ah battery, 20A draw max and don't expect major longevity. 10% current max and capacity draw max before recharging and you should get close to 20 years out of these. There are other issues like sulfation, for instance, either way, if lead acid is your poison, don't look at sealed types and stock up on distilled water and plan a daily maintenance run around the bank of ideally individual cells. (Hope you're not a smoker and have a well ventilated room for these think Hindenburg.)

LFP aka LiFePO4 batteries also shouldn't be trashed by discharging down to 0 etc. ideally you probably don't want to drop below 20% capacity remaining before adding juice to these and in my opinion you probably for the most part also only want to bring them up to 80 / max 90% of charge, they should last plenty if they don't get driven to either end of the charge extremes, the chemical reactions driven to max charge discharge is what ages these prematurely. As for current capabilities usually 1C, thus 100Ah rated can produce 100A, again, probably better to not exceed 0.5C, if you'd like these to be with you for an extended period.

Now, no-one has touched on mechanical batteries as far as I have seen, in California, there's an outfit about to, or have closed their doors, they had designed and produced a few 10kWh flywheel mechanical batteries for PG&E, but this outfit hasn't gone that route. The requirement for these was a concrete bunker, not sure of the specs exactly, but the flywheel was in a steel casing, I guess 3m cubed or somesuch, with a vaccuum and an alternator/motor assembly and some wire sticking out, I think 200kRPM was a number mentioned. So this may be just the poison for your non-Eksdom power needs, maybe. Old Mutt Co had something like this to keep the lights on for 5 to 10 minutes for critical stuff whilst the Diesel Gennies belched to life and could produce what Eksdom couldn't

Also if you have a large property with varying elevations, you could look at a pair of dams, down to the lower one at night through a turbine or two to give you back the stored energy and up the pipe by way of pumping during solar generation periods to store that energy.

Compressed gas, compression during the day and running the compressed gas through a turbine/alternator as needed.

If you have a stream/river running through you property you could supplement the Solar side with water flow generated electrons to reduce your battery capacity needs as well... so many options...

Make hydrogen gas through electrolysis and store for use in hydrogen fuel cells or whatever...

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