6 ms·

I worked in this industry as a software developer. Companies like SunCulture (who used to be a customer of ours) started maintaining all their customers on spre

by kaon_2 11mo ago

I worked in this industry as a software developer. Companies like SunCulture (who used to be a customer of ours) started maintaining all their customers on spreadsheets. But with high volume low-value sales, you need to have good software to manage this. We were a player. I once had to do a mobile money integration with a Zimbabwean bank. A dozen skype calls led to nothing. Then I visited the country, bought a local cell phone, made a few phone calls, and within several days I'd reached the developer I needed. He said: "Wait all I need to do is add this string?". "Yes.". He did so at midnight and our integration worked. Next evening we partied. It shows how integrations are often more of a human/organizational navigation more than anything technical. As for the article; the tone is hyped, and it is also somewhat true. Hundreds of millions will be using electricity. Still I want to point out one thing: This is all Solar powered DC electricity. No inverters! So you are looking at powering DC only appliances! Inverters are generally simply too expensive for this. Also the impact on income is very limited; you can't really do anything significantly more productive with the electricity, as several reports have shown. But I don't want to downplay the impact; The quality of life improvement is hard to overstate. Maybe somewhat comparable to say; you are forbidden to use any form of transport (bike, car, bus) to suddenly having all 3. Life becomes so much more convenient. For example: You don't have to take the bus anymore to town to charge your phone - yes people do this.

jjcob 11mo ago
> So you are looking at powering DC only appliances! Is there anything you actually need AC for? The big advantage of AC is that you can easily transform it for long range transmission. If you don't need that, AC is not really necessary, is it? I guess the bigger issue is the limited power -- you probably can't use a small scale solar installation for cooking or washing, not because it's DC, but because it just wont offer 1000W power.
- kaon_2 11mo ago
  Thought provoking question! I am not an electrical engineer, but arguments I heard went along these lines: Almost all existing appliance markets are AC. Are we really going to be building a complete parallel appliance market? You wouldn't be able to sell a TV from the city in the country side and vice versa. I would be keen to hear what an electrical engineer on hackernews has to say! Interestingly, when I visited the countryside, I saw some AC electrical appliances. One elder couple had an enormous 80ies style stereo-set gathering dust in the shed. I was told they were a wedding gift.
  - Gibbon1 11mo ago
    I'm sort of an electrical engineer. Increasingly things don't run directly off 120/240V directly. Anything with a power supply could be designed to run of 48V DC nominal. My slight obsession is that really the world needs a low voltage standard. Things like lighting, low power appliances don't need 120/240V.
    - snickmy 11mo ago
      I'm with you, and actually bullish on this to be a viable way forward. 48V DC has been eyed already for a potential standard to emerge. Doesn't need massive cables to deliver decent power (4A ~200W). There is enough hardware around coming from use cases like EV and Boats that could make it work. Many battery solutions already 'talk' 48v without lossy stepdown of voltage, etc. Big plus is that the regulation is A LOT less strict for <48v DC compared to AC 110/220/240.
    - KeplerBoy 11mo ago
      I'm slightly afraid of a world where USB-C PD is going to be that standard.
      - Gibbon1 11mo ago
        Perish the thought. You plugged your class EVTF television into a class ETVF receptacle and your TV caught fire? Shame shame on you.
    - lesostep 11mo ago
      I worked as an electrical civil engineer for few years. >> the world needs a low voltage standard we have high voltage standard because it means we can have low amperage to transit same VA. Because voltage doesn't kill, amperage does. It's for safety. DC is far more safer then AC, but it's not that much safer. If we convert 20A 240V AC (very bad, you can't move your hands away) to 48V DC we get a wooping 110A (instant death) But if we convert 20A 120V AC, we'd get 55A 48V DC. It's on the same level and has the same problem with moving your hands away. My country used 220V (as most do!) so switching to DC would mean huge safety threat, but for 120V countries I'd say – go for it!
- amluto 11mo ago
  Battery powered induction stoves exist, although they are not cheap enough yet. They are, however, truly excellent products. The one from Impulse Labs is not a case of “wow, I can get decent performance without the monster electric hookup it used to require” — it’s “wow, this seems to be the best stove of any sort on the market by a considerable margin, and it’s nifty that it happens to run off an integral battery, too.” If you’re so inclined, you can cook an entire meal or three on it while unplugged. If someone wants to make them work in rural areas like this, I think the necessary ingredients will be: 1. Cheaper batteries. These are likely coming. 2. More energy. A meal might require 1 kWh or more. (Or less — scrambled eggs won’t require much energy at all.) This is solvable with more panels. 3. Copper. The coil itself is a decent sized hunk of copper. I assume this is part of why cheap little portable induction cooktops still cost $50 or more. 4. Power electronics? I’m not an expert, and I have no idea how much of the cost comes from the power electronics, but integrating the battery and the induction heater seems like it should result in a dramatically simpler system than, say, producing AC from a battery and then converting that AC into a form that will power the coil. The current list price of the Impulse Labs stove includes a hilariously high power output, and a stove targeting rural Africa could be 1/5 as powerful and would still be fantastic. I wouldn’t be surprised if someone could squeeze the cost of a decent battery powered stove down to $200 in a few years if they had appropriate scale.
  - jjcob 11mo ago
    I looked up that Impulse Labs induction hob. Holy Shit, 10kW peak on a single burner is ridiculous! I already managed to ruin a pan with just 3.7kW (heated it while empty), and I tought that was a lot. However, I think the cost is probably mostly the battery. Our induction hob (max power per burner 3.7kW / 7.2kW total) costs only 10% of the battery powered stove. Also, at the low cost, induction is a non-starter. Resistive heating elements are dirt cheap, and the efficiency is not much less than induction. Induction is just way nicer :)
    - myrmidon 11mo ago
      Battery power for an oven like this is not necessarily cost-prohibitive; if you want cost effectiveness and long lifetime, LiFePo cells can be had for ~$60/kwh, which would be under <$200 for an ImpulseLabs sized oven. Absolutely agree on resistive heating for cost effectiveness: Some cheap cells, resistive heating and minimal power electronics would probably be the way to go for the African market.
- rozab 11mo ago
  Lowtech magazine recently had an article about cooking with solar power: https://solar.lowtechmagazine.com/2025/10/how-to-build-a-solar-powered-electric-oven/ https://solar.lowtechmagazine.com/2025/10/how-to-build-a-sol...
  - Driver8 11mo ago
    They also did one on using DC directly instead of AC and the benefits of doing it: https://solar.lowtechmagazine.com/2016/04/slow-electricity-the-return-of-dc-power/ https://solar.lowtechmagazine.com/2016/04/slow-electricity-t...
- snickmy 11mo ago
  AC makes power distribution easier (because you can have modulated phases). So it's correct to say it's easier to move it over a long distance. Additionally, and i'm really simplifying, at parity of nominal voltage, you can move a lot more power, at a lower dissipation cost. This has resulted in few high power electronics to be AC native (ie.: no AC - DC - AC conversion). Think about motors in the various appliances, etc. It doesn't need to be like that, investment in DC car motors have pushed the industry to optimizes design, and get similar power output of the motor at lower energy consumption. That said, if you are a manufacturer of an appliance and you have an addressable user base of billions with AC, and a 'potential new user base' with DC... you might just want to swallow the cost and add a DC / AC converter for the sake to not have to produce two variants of the most complex / costly item (the motor in this case).
  - brohee 11mo ago
    That wheel has turned. The king of long distance transmission is now HVDC, to be point of sometimes being used intra-grid and not just for interconnects.
    - snickmy 11mo ago
      That is correct. When that will be available is the hard thing to guess. There are currently enough production of electricity that is motor based (think about gas turbine, water turbines, etc), so there is a nice benefit of having AC at source and distribution. The infrastructure needs to change. With an average lifetime of a substation in the 50-75years, it's hard to expect we'll overhaul completely the distribution system over night. It's also hard for me to understand the power loss between the two scenarios (AC production, ac distribution, ac/dc conversion , dc consumption) and DC production, dc stepup to HVDC, dc distribution, DC stepdown and DC consumption). Even 1% at national scale means millions, so the entire business case might be anchored there. I'm sure there are smarter people than me here that can cast some light on this
      - SJC_Hacker 11mo ago
        DC is hard to step down. You dont want 10,000 volts going into every house. AC sill be used for distribution that isnt very long distance
- potato3732842 11mo ago
  Ignoring the cost of the battery how much does a cordless drill that'll break your wrist cost? A non-trivial amount more than the corded one that's for sure. You're gonna see comparable cost difference in just about every "final appliance" that actually turns the jiggling electrons into results (whether those results are work or heat). Alternating current is substantially easier to step up/down in voltage, much nicer to anything that modulated current flow and has a lot of convenient aspects for motors. Like for like the DC solution costs just a little bit more every step of the way. Even if you're not doing long distance transmission the cost of all those things that are worse about DC are going to be bore across the entirety of your economy that uses AC. DC makes sense here because the supply chain is so dysfunctional that making the "better" solution work would actually cost more than the "12v doodads from china" style solution. Eventually as electrification continues the choice of DC will become a drag though.
  - kragen 11mo ago
    I don't think this is correct. Drills use "universal" motors which don't care if they're running on AC or DC, because 60Hz AC motors are limited to 3600rpm, which isn't nearly fast enough for a drill, and also because it's not okay if the drill stops working if it hits resistance and slows down. (Most AC motors run at a fraction of that.) You can run a cheap electric drill off 120Vdc just as easily as 120Vac. Getting it to run on 48Vdc or 30Vdc involves rewinding the motor with the same amount of copper in the form of thicker wire. Fancy drills already have a lot of electronics that do care about the polarity of the applied voltage, but they usually want it to be DC. Once you get anything more sophisticated than phase-angle control with a TRIAC, you're using MOSFETs anyway, and you can often use half as many of them if you're using DC, because MOSFETs like DC.
- mschuster91 11mo ago
  > I guess the bigger issue is the limited power -- you probably can't use a small scale solar installation for cooking or washing, not because it's DC, but because it just wont offer 1000W power. Your average lead-acid starter battery can easily do that - 1 kW is less than 100 amps at 12V, less than 50A if you wire two in series. 200 Ah means about four hours worth of runtime. The problem is switching off higher DC voltages and currents. AC is easy, it traverses through 0V 100 (or 120 in the US) times a second. But DC? The arc is just going on. That's why most electrical equipment, from switches over automated breakers to fuses, has distinct ratings for AC and DC, with DC ratings sometimes being half the AC rating. Additionally, larger DC networks tend to have issues with weird current flows and electrochemical corrosion.
  - nativeit 11mo ago
    Could it easily do that for several minutes at full chap? Under the load of a full washing machine?
    - kragen 11mo ago
      No, only for about a minute or two. But there are a lot of lithium-ion batteries capable of 10C discharge rates which can survive several minutes of max load. For 100 amps I am guessing you'd need 10 amp-hours of 10C-capable lithium-ion batteries, roughly a 4S4P or 4P4S configuration of 10C 18650s. I think this is about US$128 of batteries, a similar price to the car battery but much smaller and more inflammable.
- kragen 11mo ago
  Thermal energy storage solves the problem of cooking and washing. I have a half-liter thermos bottle that leaks about 0.3 watts at ΔT ≈ 50° (635g of water dropped from 71.9° to 69.8° over five hours and 8 minutes), so any power supply averaging over about a watt would be sufficient to boil water in it—eventually. If you needed to do it in the 4 hours the sun was near peak on a single day, you'd need at least 15 watts. (I don't live in Africa, but I do live in a third-world country. Blown-glass thermoses are pretty widely available because, although they're fragile, they're light and never wear out, just shatter.) Sand batteries are potentially extremely cheap and can easily deliver cooking temperatures. A super-low-tech version of this approach is "salt frying", where you preheat a few kg of table salt (melting point 800.7°) to frying temperature, then stir dry food into it. Most of the salt won't stick to the food, but the few grains that do won't cause the edibility problems that sand would. TCES potentially offers much greater storage density and much greater controllability than these sensible-heat energy-storage technologies, since you can store the "heat" indefinitely. Phase-change thermal energy storage is another potentially appealing possibility, potentially offering a stable cooking temperature for many hours, although I don't know of any suitable materials. The MgCl₂-KCl–NaCl eutectic, for example, doesn't melt until 401°. Maybe something like calcium stearate (m.p. 150°–180°) would work, but its heat of fusion isn't great, I'd be worried about long-term stability, and although it's easy to get anywhere in the world, it's probably a lot more expensive than salt. (Table salt is US$100/tonne, but the eutectic mentioned above would be closer to US$400/tonne.)
chrneu 11mo ago
My understanding is that the main benefit of small solar like this is to get combustion out of the home, specifically kerosene or dung lamps/stoves. A lot of folks have respiratory issues because they cook indoors.
- kaon_2 11mo ago
  Yes and no. You are right that indoor cooking (or outdoor on wood) is indeed one of the biggest causes of death worldwide. It dwarfs deaths by malaria. And where people don't die, it causes respiratory issues. I don't know the math but it is similar to smoking X cigarettes a day. - sidenote - You always learn that in centuries past, people didn't grow old. I never knew why but my current suspicion is that air pollution by stoves and hearths was probably the top 3 cause. However, cooking isn't (yet) solved by solar. Making heat from electricity is hard! Clean Cooking solutions often use propane, butane, or wooden pallets. Clean Cooking companies face all of the same issues as the Off grid solar companies of this article. But you'd be surprised that it is really considered a different industry. Customers and price plans are the same, but funding often comes from different sources. Making affordable, electric, clean cooking solutions would be one of the most impactful inventions of our generation. Even then, challenges remain: No cultural activity is as steeped in tradition as cooking, and convincing people to change this, resulting in different tasting meals, is hard. Particular if it is the man deciding on the money, and the woman doing the work.
  - looofooo0 11mo ago
    alibaba.com/product-detail/Solar-DC-12V-24V-Battery-Powered_60758353185.html
  - razakel 11mo ago
    >I don't know the math but it is similar to smoking X cigarettes a day. The article says two packs a day.
    - kaon_2 11mo ago
      I oversaw that thank you :)
duckmysick 11mo ago
> Companies like SunCulture (who used to be a customer of ours) started maintaining all their customers on spreadsheets. But with high volume low-value sales, you need to have good software to manage this. That's pretty interesting. Can you tell us more what kind of problems your software solved and how you convinced them to move from the spreadsheets? I tried something similar (in another industry) and it's a mixed bag. Companies often straight up refuse to move past the spreadsheets even though it creates a significant backlog on their side.
- kaon_2 11mo ago
  Happy to oblige. Basically we digitized a company from spreadsheets or paper to ERP. We'd introduce accounting software, stock management software, help desk software. But the biggest thing you need is some kind of "Loan Account Management Software" which is the center piece. This centerpiece tracks the outstanding loan amount that each customer has. It sutomatically sends payment reminder SMS messages a few days before payments are due. It connects to the hardware with internet-of-things to turn it off if payments aren't made. It connects to the bank to ensure payments are there, and confirms when payments are made. Really fun software to build with many different parts. There were SaaS providers for this. In the beginning (2015) there was only 1 player, Angaza (Reed Hastings mentioned in the article is one of their sales guys). Nowadays there are a handful; PaygOps, BBoX pulse (not sure if that still exists), and a few smaller ones. They charge like $2-$7 per device managed on the platform. Convincing customer to take this up was not hard at all. You pretty much needed it to run your operations on anything more than 100 customers, and as the above article shows, scale had big advantages. Moreover; if you could show to investors that you had the software infrastructure scale, they were significantly likely to give money. It was boom time until corona hit. Everyone was expecting 30% YoY growth like until 2019, but then everything stagnated. Many companies went bankrupt and a lot of consolidation happened in the distributor market. Companies saved money on their software first, and we called it a day. In the manufacturing industry where I am now, I fully agree with the mixed bag. Companies are old, with many old people, they stay small and don't necessarily need to scale or "grow forever". They are conservative and happy with the way things are.
veunes 11mo ago
Totally agree on the DC limitation point too. A lot of folks outside the space assume these systems are just mini-versions of Western home solar setups, but they're not

by kaon_2 11mo ago

jjcob 11mo ago

> So you are looking at powering DC only appliances! Is there anything you actually need AC for? The big advantage of AC is that you can easily transform it for long range transmission. If you don't need that, AC is not really necessary, is it? I guess the bigger issue is the limited power -- you probably can't use a small scale solar installation for cooking or washing, not because it's DC, but because it just wont offer 1000W power.

kaon_2 11mo ago
Thought provoking question! I am not an electrical engineer, but arguments I heard went along these lines: Almost all existing appliance markets are AC. Are we really going to be building a complete parallel appliance market? You wouldn't be able to sell a TV from the city in the country side and vice versa. I would be keen to hear what an electrical engineer on hackernews has to say! Interestingly, when I visited the countryside, I saw some AC electrical appliances. One elder couple had an enormous 80ies style stereo-set gathering dust in the shed. I was told they were a wedding gift.
- Gibbon1 11mo ago
  I'm sort of an electrical engineer. Increasingly things don't run directly off 120/240V directly. Anything with a power supply could be designed to run of 48V DC nominal. My slight obsession is that really the world needs a low voltage standard. Things like lighting, low power appliances don't need 120/240V.
  - snickmy 11mo ago
    I'm with you, and actually bullish on this to be a viable way forward. 48V DC has been eyed already for a potential standard to emerge. Doesn't need massive cables to deliver decent power (4A ~200W). There is enough hardware around coming from use cases like EV and Boats that could make it work. Many battery solutions already 'talk' 48v without lossy stepdown of voltage, etc. Big plus is that the regulation is A LOT less strict for <48v DC compared to AC 110/220/240.
  - KeplerBoy 11mo ago
    I'm slightly afraid of a world where USB-C PD is going to be that standard.
    - Gibbon1 11mo ago
      Perish the thought. You plugged your class EVTF television into a class ETVF receptacle and your TV caught fire? Shame shame on you.
  - lesostep 11mo ago
    I worked as an electrical civil engineer for few years. >> the world needs a low voltage standard we have high voltage standard because it means we can have low amperage to transit same VA. Because voltage doesn't kill, amperage does. It's for safety. DC is far more safer then AC, but it's not that much safer. If we convert 20A 240V AC (very bad, you can't move your hands away) to 48V DC we get a wooping 110A (instant death) But if we convert 20A 120V AC, we'd get 55A 48V DC. It's on the same level and has the same problem with moving your hands away. My country used 220V (as most do!) so switching to DC would mean huge safety threat, but for 120V countries I'd say – go for it!
amluto 11mo ago
Battery powered induction stoves exist, although they are not cheap enough yet. They are, however, truly excellent products. The one from Impulse Labs is not a case of “wow, I can get decent performance without the monster electric hookup it used to require” — it’s “wow, this seems to be the best stove of any sort on the market by a considerable margin, and it’s nifty that it happens to run off an integral battery, too.” If you’re so inclined, you can cook an entire meal or three on it while unplugged. If someone wants to make them work in rural areas like this, I think the necessary ingredients will be: 1. Cheaper batteries. These are likely coming. 2. More energy. A meal might require 1 kWh or more. (Or less — scrambled eggs won’t require much energy at all.) This is solvable with more panels. 3. Copper. The coil itself is a decent sized hunk of copper. I assume this is part of why cheap little portable induction cooktops still cost $50 or more. 4. Power electronics? I’m not an expert, and I have no idea how much of the cost comes from the power electronics, but integrating the battery and the induction heater seems like it should result in a dramatically simpler system than, say, producing AC from a battery and then converting that AC into a form that will power the coil. The current list price of the Impulse Labs stove includes a hilariously high power output, and a stove targeting rural Africa could be 1/5 as powerful and would still be fantastic. I wouldn’t be surprised if someone could squeeze the cost of a decent battery powered stove down to $200 in a few years if they had appropriate scale.
- jjcob 11mo ago
  I looked up that Impulse Labs induction hob. Holy Shit, 10kW peak on a single burner is ridiculous! I already managed to ruin a pan with just 3.7kW (heated it while empty), and I tought that was a lot. However, I think the cost is probably mostly the battery. Our induction hob (max power per burner 3.7kW / 7.2kW total) costs only 10% of the battery powered stove. Also, at the low cost, induction is a non-starter. Resistive heating elements are dirt cheap, and the efficiency is not much less than induction. Induction is just way nicer :)
  - myrmidon 11mo ago
    Battery power for an oven like this is not necessarily cost-prohibitive; if you want cost effectiveness and long lifetime, LiFePo cells can be had for ~$60/kwh, which would be under <$200 for an ImpulseLabs sized oven. Absolutely agree on resistive heating for cost effectiveness: Some cheap cells, resistive heating and minimal power electronics would probably be the way to go for the African market.
rozab 11mo ago
Lowtech magazine recently had an article about cooking with solar power: https://solar.lowtechmagazine.com/2025/10/how-to-build-a-solar-powered-electric-oven/ https://solar.lowtechmagazine.com/2025/10/how-to-build-a-sol...
- Driver8 11mo ago
  They also did one on using DC directly instead of AC and the benefits of doing it: https://solar.lowtechmagazine.com/2016/04/slow-electricity-the-return-of-dc-power/ https://solar.lowtechmagazine.com/2016/04/slow-electricity-t...
snickmy 11mo ago
AC makes power distribution easier (because you can have modulated phases). So it's correct to say it's easier to move it over a long distance. Additionally, and i'm really simplifying, at parity of nominal voltage, you can move a lot more power, at a lower dissipation cost. This has resulted in few high power electronics to be AC native (ie.: no AC - DC - AC conversion). Think about motors in the various appliances, etc. It doesn't need to be like that, investment in DC car motors have pushed the industry to optimizes design, and get similar power output of the motor at lower energy consumption. That said, if you are a manufacturer of an appliance and you have an addressable user base of billions with AC, and a 'potential new user base' with DC... you might just want to swallow the cost and add a DC / AC converter for the sake to not have to produce two variants of the most complex / costly item (the motor in this case).
- brohee 11mo ago
  That wheel has turned. The king of long distance transmission is now HVDC, to be point of sometimes being used intra-grid and not just for interconnects.
  - snickmy 11mo ago
    That is correct. When that will be available is the hard thing to guess. There are currently enough production of electricity that is motor based (think about gas turbine, water turbines, etc), so there is a nice benefit of having AC at source and distribution. The infrastructure needs to change. With an average lifetime of a substation in the 50-75years, it's hard to expect we'll overhaul completely the distribution system over night. It's also hard for me to understand the power loss between the two scenarios (AC production, ac distribution, ac/dc conversion , dc consumption) and DC production, dc stepup to HVDC, dc distribution, DC stepdown and DC consumption). Even 1% at national scale means millions, so the entire business case might be anchored there. I'm sure there are smarter people than me here that can cast some light on this
    - SJC_Hacker 11mo ago
      DC is hard to step down. You dont want 10,000 volts going into every house. AC sill be used for distribution that isnt very long distance
potato3732842 11mo ago
Ignoring the cost of the battery how much does a cordless drill that'll break your wrist cost? A non-trivial amount more than the corded one that's for sure. You're gonna see comparable cost difference in just about every "final appliance" that actually turns the jiggling electrons into results (whether those results are work or heat). Alternating current is substantially easier to step up/down in voltage, much nicer to anything that modulated current flow and has a lot of convenient aspects for motors. Like for like the DC solution costs just a little bit more every step of the way. Even if you're not doing long distance transmission the cost of all those things that are worse about DC are going to be bore across the entirety of your economy that uses AC. DC makes sense here because the supply chain is so dysfunctional that making the "better" solution work would actually cost more than the "12v doodads from china" style solution. Eventually as electrification continues the choice of DC will become a drag though.
- kragen 11mo ago
  I don't think this is correct. Drills use "universal" motors which don't care if they're running on AC or DC, because 60Hz AC motors are limited to 3600rpm, which isn't nearly fast enough for a drill, and also because it's not okay if the drill stops working if it hits resistance and slows down. (Most AC motors run at a fraction of that.) You can run a cheap electric drill off 120Vdc just as easily as 120Vac. Getting it to run on 48Vdc or 30Vdc involves rewinding the motor with the same amount of copper in the form of thicker wire. Fancy drills already have a lot of electronics that do care about the polarity of the applied voltage, but they usually want it to be DC. Once you get anything more sophisticated than phase-angle control with a TRIAC, you're using MOSFETs anyway, and you can often use half as many of them if you're using DC, because MOSFETs like DC.
mschuster91 11mo ago
> I guess the bigger issue is the limited power -- you probably can't use a small scale solar installation for cooking or washing, not because it's DC, but because it just wont offer 1000W power. Your average lead-acid starter battery can easily do that - 1 kW is less than 100 amps at 12V, less than 50A if you wire two in series. 200 Ah means about four hours worth of runtime. The problem is switching off higher DC voltages and currents. AC is easy, it traverses through 0V 100 (or 120 in the US) times a second. But DC? The arc is just going on. That's why most electrical equipment, from switches over automated breakers to fuses, has distinct ratings for AC and DC, with DC ratings sometimes being half the AC rating. Additionally, larger DC networks tend to have issues with weird current flows and electrochemical corrosion.
- nativeit 11mo ago
  Could it easily do that for several minutes at full chap? Under the load of a full washing machine?
  - kragen 11mo ago
    No, only for about a minute or two. But there are a lot of lithium-ion batteries capable of 10C discharge rates which can survive several minutes of max load. For 100 amps I am guessing you'd need 10 amp-hours of 10C-capable lithium-ion batteries, roughly a 4S4P or 4P4S configuration of 10C 18650s. I think this is about US$128 of batteries, a similar price to the car battery but much smaller and more inflammable.
kragen 11mo ago
Thermal energy storage solves the problem of cooking and washing. I have a half-liter thermos bottle that leaks about 0.3 watts at ΔT ≈ 50° (635g of water dropped from 71.9° to 69.8° over five hours and 8 minutes), so any power supply averaging over about a watt would be sufficient to boil water in it—eventually. If you needed to do it in the 4 hours the sun was near peak on a single day, you'd need at least 15 watts. (I don't live in Africa, but I do live in a third-world country. Blown-glass thermoses are pretty widely available because, although they're fragile, they're light and never wear out, just shatter.) Sand batteries are potentially extremely cheap and can easily deliver cooking temperatures. A super-low-tech version of this approach is "salt frying", where you preheat a few kg of table salt (melting point 800.7°) to frying temperature, then stir dry food into it. Most of the salt won't stick to the food, but the few grains that do won't cause the edibility problems that sand would. TCES potentially offers much greater storage density and much greater controllability than these sensible-heat energy-storage technologies, since you can store the "heat" indefinitely. Phase-change thermal energy storage is another potentially appealing possibility, potentially offering a stable cooking temperature for many hours, although I don't know of any suitable materials. The MgCl₂-KCl–NaCl eutectic, for example, doesn't melt until 401°. Maybe something like calcium stearate (m.p. 150°–180°) would work, but its heat of fusion isn't great, I'd be worried about long-term stability, and although it's easy to get anywhere in the world, it's probably a lot more expensive than salt. (Table salt is US$100/tonne, but the eutectic mentioned above would be closer to US$400/tonne.)

chrneu 11mo ago

My understanding is that the main benefit of small solar like this is to get combustion out of the home, specifically kerosene or dung lamps/stoves. A lot of folks have respiratory issues because they cook indoors.

kaon_2 11mo ago
Yes and no. You are right that indoor cooking (or outdoor on wood) is indeed one of the biggest causes of death worldwide. It dwarfs deaths by malaria. And where people don't die, it causes respiratory issues. I don't know the math but it is similar to smoking X cigarettes a day. - sidenote - You always learn that in centuries past, people didn't grow old. I never knew why but my current suspicion is that air pollution by stoves and hearths was probably the top 3 cause. However, cooking isn't (yet) solved by solar. Making heat from electricity is hard! Clean Cooking solutions often use propane, butane, or wooden pallets. Clean Cooking companies face all of the same issues as the Off grid solar companies of this article. But you'd be surprised that it is really considered a different industry. Customers and price plans are the same, but funding often comes from different sources. Making affordable, electric, clean cooking solutions would be one of the most impactful inventions of our generation. Even then, challenges remain: No cultural activity is as steeped in tradition as cooking, and convincing people to change this, resulting in different tasting meals, is hard. Particular if it is the man deciding on the money, and the woman doing the work.
- looofooo0 11mo ago
  alibaba.com/product-detail/Solar-DC-12V-24V-Battery-Powered_60758353185.html
- razakel 11mo ago
  >I don't know the math but it is similar to smoking X cigarettes a day. The article says two packs a day.
  - kaon_2 11mo ago
    I oversaw that thank you :)

duckmysick 11mo ago

> Companies like SunCulture (who used to be a customer of ours) started maintaining all their customers on spreadsheets. But with high volume low-value sales, you need to have good software to manage this. That's pretty interesting. Can you tell us more what kind of problems your software solved and how you convinced them to move from the spreadsheets? I tried something similar (in another industry) and it's a mixed bag. Companies often straight up refuse to move past the spreadsheets even though it creates a significant backlog on their side.

kaon_2 11mo ago
Happy to oblige. Basically we digitized a company from spreadsheets or paper to ERP. We'd introduce accounting software, stock management software, help desk software. But the biggest thing you need is some kind of "Loan Account Management Software" which is the center piece. This centerpiece tracks the outstanding loan amount that each customer has. It sutomatically sends payment reminder SMS messages a few days before payments are due. It connects to the hardware with internet-of-things to turn it off if payments aren't made. It connects to the bank to ensure payments are there, and confirms when payments are made. Really fun software to build with many different parts. There were SaaS providers for this. In the beginning (2015) there was only 1 player, Angaza (Reed Hastings mentioned in the article is one of their sales guys). Nowadays there are a handful; PaygOps, BBoX pulse (not sure if that still exists), and a few smaller ones. They charge like $2-$7 per device managed on the platform. Convincing customer to take this up was not hard at all. You pretty much needed it to run your operations on anything more than 100 customers, and as the above article shows, scale had big advantages. Moreover; if you could show to investors that you had the software infrastructure scale, they were significantly likely to give money. It was boom time until corona hit. Everyone was expecting 30% YoY growth like until 2019, but then everything stagnated. Many companies went bankrupt and a lot of consolidation happened in the distributor market. Companies saved money on their software first, and we called it a day. In the manufacturing industry where I am now, I fully agree with the mixed bag. Companies are old, with many old people, they stay small and don't necessarily need to scale or "grow forever". They are conservative and happy with the way things are.

veunes 11mo ago

Totally agree on the DC limitation point too. A lot of folks outside the space assume these systems are just mini-versions of Western home solar setups, but they're not