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$300/kWh for home storage is readily available. E.g. https://signaturesolar.com/eg4-ll-lithium-battery-24v-200ah/ https://signaturesolar.com/eg4-ll-lithium-bat

$300/kWh for home storage is readily available. E.g. https://signaturesolar.com/eg4-ll-lithium-battery-24v-200ah/ https://signaturesolar.com/eg4-ll-lithium-battery-24v-200ah/

raxxorraxor 4y ago
True, there are better prices by now. But 5kWh? I thought my smartphone would have that by now... Perhaps 200kWh is a bit exaggerated. And yes you also need a good quality inverter for your home that synchronizes with the net, but I actually don't believe this to be expensive high tech... Ideally I wouldn't want to put the energy I generate with solar, wind or differently back into the power net. In my country you basically give that away for free. There are reasons for that, but the most efficient way would be to use the energy yourself as much as possible. Sure, 5kWH is enough to soften peaks and there could already be huge benefit to this. But a bit more capacity would be really nice to really safe the energy of sunny days. Reminds me if disappointing USPs that let me play Tetris for an additional 7-8 minutes before I feel like civilization has broken down completely until power comes back.
- vbezhenar 4y ago
  Phone battery is something like 4V. Watts depend on voltage. I guess home batteries use other voltage so their watt actually provides more electricity.
  - raxxorraxor 4y ago
    No, Watts should be independent of voltage, it is the product of voltage and ampere (don't know the exact English terms here). You perhaps mean ampere hours, I think that is often used for phones. But it is only ever meaningful if you have the respective fixed voltage and it often make sense for a batteries to quickly calculate how long they should last if you know how much ampere a device draws. It could also become a sensible metric if we always talk about 120V/240V for general household appliances of course.
    - thehappypm 4y ago
      I think what they’re talking about is the amp-hour measure of battery capacity, which is common in electronics, but converting to actual energy requires knowing the voltage.
    - beckingz 4y ago
      Voltage isn't fixed across a discharge cycle. As a chemical battery discharges, the voltage drops, so at the same load in amps you get less watts later.
    - raxxorraxor 4y ago
      edit: Wh is independent of voltage I mean... of course a product is dependent on its factors...
      - vbezhenar 4y ago
        You're right, I mangled Ah and Wh in my head, sorry. 4V 1Wh battery and 24V 1Wh batteries are equally useful. Your numbers are a little bit off though. I just googled some power bank (which is supposedly better than smartphone). It claims to provide 20 000 mAh at 5V. So it's 20 Ah at 5V or 100 Wh. I think most smartphones are around 10-20 Wh. Far from 5 kWh. But this discrepancy was already noted in other comments.
- pjc50 4y ago
  Phones are more like 10-15 watt-hours, not kWh.
coding123 4y ago
Those 5kwh "server" batteries are overpriced compared to prismatic cells and a bms.
- driverdan 4y ago
  They aren't when you factor in labor and the other components involved (wiring, breakers, terminals, steel box, etc). I've built my own system in my RV but will be going with racked batteries for my house due to how much time and effort they will save.
mnw21cam 4y ago
Deep cycle lead-acid batteries are available around £100/kWh, and they'll last pretty-much as long as a LiFePo if managed sensibly.
- thescriptkiddie 4y ago
  > they'll last pretty-much as long as a LiFePo citation needed
- sgt 4y ago
  Managing lead-acid sensibly in my experience means never letting levels go below 40%. Temperature too I suppose. I didn't know they could last as long as LiFePo though. Is this really true? If this is true, why don't we just use more lead-acid batteries then?
  - mnw21cam 4y ago
    LiFePo can last longer than Lead-Acid. It depends on the usage. LiFePo has a very high maximum cycle count. But after ten years, they'll die anyway. The only way that you can actually achieve a cycle count as high as the specification says is if you're cycling the battery two or three times a day, which I can believe if you're doing grid-levelling, but not if you're providing backup for your solar panels. For lead-acid batteries, be aware of the difference between normal lead-acid, which are optimised for standby operation, and deep-cycle lead-acid, which are optimised for long life under regular cycling. Normal lead-acid batteries will die very quickly if cycled - they're designed to be charged all the time, and drawn on for very short period, like a car battery or a UPS. Deep-cycle lead-acid batteries age by cycling, in contrast to LiFePo, which age by elapsed time. Their maximum cycle count is much lower than LiFePo, but if you're cycling them every couple of days, like in an off-grid solar project, and you're avoiding draining them below around 40%, then they can last 10 years. So, if you want to cycle your batteries two or three times a day, then LiFePo is going to last a lot longer than Lead-Acid. But if you're cycling every couple of days and limiting the drain, then they can last about the same amount of time. It depends on the usage. What helps with Lead-Acid is because it is that much cheaper than LiFePo, you can buy a larger capacity Lead-Acid battery for the same or less money, and then for the same performance requirements that larger battery will be drained less and at a lower rate, and therefore be less stressed and even last longer. I think we don't use Lead-Acid as much as we do for several reasons: 1. Lead-Acid batteries have a reputation of flaking on us after a depressingly short amount of time. But that reputation has been earned from normal Lead-Acid batteries, not deep cycle ones. 2. People get scared by the lead in them, and how lead is toxic and we should be stopping using lead in everything. But really, lead in these batteries is not a danger to us, and Lead-Acid batteries are one of the best recycling success stories in the world. That lead isn't generally getting out into the environment. LiFePo batteries are much harder to recycle. 3. Electricians recommend installing expensive stuff, because then they get a bigger commission. 4. Lead-Acid batteries are commodities, but LiFePo batteries are new and exciting, and have aggressive marketing. 5. Lead-Acid are bigger and heavier for the same capacity than LiFePo. So, a LiFePo installation is going to look prettier in a nice consumer unit and be easier to install. They're heavy enough as it is.

$300/kWh for home storage is readily available. E.g. https://signaturesolar.com/eg4-ll-lithium-battery-24v-200ah/ https://signaturesolar.com/eg4-ll-lithium-battery-24v-200ah/

raxxorraxor 4y ago

True, there are better prices by now. But 5kWh? I thought my smartphone would have that by now... Perhaps 200kWh is a bit exaggerated. And yes you also need a good quality inverter for your home that synchronizes with the net, but I actually don't believe this to be expensive high tech... Ideally I wouldn't want to put the energy I generate with solar, wind or differently back into the power net. In my country you basically give that away for free. There are reasons for that, but the most efficient way would be to use the energy yourself as much as possible. Sure, 5kWH is enough to soften peaks and there could already be huge benefit to this. But a bit more capacity would be really nice to really safe the energy of sunny days. Reminds me if disappointing USPs that let me play Tetris for an additional 7-8 minutes before I feel like civilization has broken down completely until power comes back.

vbezhenar 4y ago
Phone battery is something like 4V. Watts depend on voltage. I guess home batteries use other voltage so their watt actually provides more electricity.
- raxxorraxor 4y ago
  No, Watts should be independent of voltage, it is the product of voltage and ampere (don't know the exact English terms here). You perhaps mean ampere hours, I think that is often used for phones. But it is only ever meaningful if you have the respective fixed voltage and it often make sense for a batteries to quickly calculate how long they should last if you know how much ampere a device draws. It could also become a sensible metric if we always talk about 120V/240V for general household appliances of course.
  - thehappypm 4y ago
    I think what they’re talking about is the amp-hour measure of battery capacity, which is common in electronics, but converting to actual energy requires knowing the voltage.
  - beckingz 4y ago
    Voltage isn't fixed across a discharge cycle. As a chemical battery discharges, the voltage drops, so at the same load in amps you get less watts later.
  - raxxorraxor 4y ago
    edit: Wh is independent of voltage I mean... of course a product is dependent on its factors...
    - vbezhenar 4y ago
      You're right, I mangled Ah and Wh in my head, sorry. 4V 1Wh battery and 24V 1Wh batteries are equally useful. Your numbers are a little bit off though. I just googled some power bank (which is supposedly better than smartphone). It claims to provide 20 000 mAh at 5V. So it's 20 Ah at 5V or 100 Wh. I think most smartphones are around 10-20 Wh. Far from 5 kWh. But this discrepancy was already noted in other comments.
pjc50 4y ago
Phones are more like 10-15 watt-hours, not kWh.

coding123 4y ago

Those 5kwh "server" batteries are overpriced compared to prismatic cells and a bms.

driverdan 4y ago
They aren't when you factor in labor and the other components involved (wiring, breakers, terminals, steel box, etc). I've built my own system in my RV but will be going with racked batteries for my house due to how much time and effort they will save.

mnw21cam 4y ago

Deep cycle lead-acid batteries are available around £100/kWh, and they'll last pretty-much as long as a LiFePo if managed sensibly.

thescriptkiddie 4y ago
> they'll last pretty-much as long as a LiFePo citation needed
sgt 4y ago
Managing lead-acid sensibly in my experience means never letting levels go below 40%. Temperature too I suppose. I didn't know they could last as long as LiFePo though. Is this really true? If this is true, why don't we just use more lead-acid batteries then?
- mnw21cam 4y ago
  LiFePo can last longer than Lead-Acid. It depends on the usage. LiFePo has a very high maximum cycle count. But after ten years, they'll die anyway. The only way that you can actually achieve a cycle count as high as the specification says is if you're cycling the battery two or three times a day, which I can believe if you're doing grid-levelling, but not if you're providing backup for your solar panels. For lead-acid batteries, be aware of the difference between normal lead-acid, which are optimised for standby operation, and deep-cycle lead-acid, which are optimised for long life under regular cycling. Normal lead-acid batteries will die very quickly if cycled - they're designed to be charged all the time, and drawn on for very short period, like a car battery or a UPS. Deep-cycle lead-acid batteries age by cycling, in contrast to LiFePo, which age by elapsed time. Their maximum cycle count is much lower than LiFePo, but if you're cycling them every couple of days, like in an off-grid solar project, and you're avoiding draining them below around 40%, then they can last 10 years. So, if you want to cycle your batteries two or three times a day, then LiFePo is going to last a lot longer than Lead-Acid. But if you're cycling every couple of days and limiting the drain, then they can last about the same amount of time. It depends on the usage. What helps with Lead-Acid is because it is that much cheaper than LiFePo, you can buy a larger capacity Lead-Acid battery for the same or less money, and then for the same performance requirements that larger battery will be drained less and at a lower rate, and therefore be less stressed and even last longer. I think we don't use Lead-Acid as much as we do for several reasons: 1. Lead-Acid batteries have a reputation of flaking on us after a depressingly short amount of time. But that reputation has been earned from normal Lead-Acid batteries, not deep cycle ones. 2. People get scared by the lead in them, and how lead is toxic and we should be stopping using lead in everything. But really, lead in these batteries is not a danger to us, and Lead-Acid batteries are one of the best recycling success stories in the world. That lead isn't generally getting out into the environment. LiFePo batteries are much harder to recycle. 3. Electricians recommend installing expensive stuff, because then they get a bigger commission. 4. Lead-Acid batteries are commodities, but LiFePo batteries are new and exciting, and have aggressive marketing. 5. Lead-Acid are bigger and heavier for the same capacity than LiFePo. So, a LiFePo installation is going to look prettier in a nice consumer unit and be easier to install. They're heavy enough as it is.