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100% solar powered maisonette possible?
tom_boy
#81 Posted : Monday, December 21, 2020 1:50:16 PM
Rank: Member


Joined: 2/20/2007
Posts: 767
amorphous wrote:
tom_boy wrote:
amorphous wrote:
winmak wrote:
kayhara wrote:
back-up muhimu, I started mine with the vispra 1000 watt inverter charger and the 200ah gel battery from sollatek, I charge with kplc, I will not interfere with that system which I think is under used it powers tv 70 watts, ceiling fan 75 watts, router 7 watts, bulbs 40 watts hifi 35 watts.
I am getting the vispra 2000 watts inverter charger and 2x 200 ah gel batteries and 2x 350 watt Schneider solar panels, this will keep my freezer, fridge, 4 ceiling fans, an induction cooker can continue running, also the 1000 watt set-up will charge from this, only my oven, microwave, shower, iron and kettle will be on kplc.


Good stuff...

My 'solar consultant' has suggested to me this for a mansionnette with avg use of 4kWh/day, heaviest appliances being 3 shower heaters, fridge, iron box, water pump and microwave:

1. 4 pannels of 275 watts
2. 2 batteries (cant remember the specs)
3. 2.4kW hybrid inverter (to be done in a way such that it can automatically draw power from KPLC once the batteries go lower than a preset figure)

This comes closest to near total off grid with KPLC as the back up during periods of heavy use (which he advices I do during the day at full sun glow - like water pumping and ironing... and try to stagger usage so that I dont have the heavy users running at the same time... otherwise I require a 3kW inverter which pushes the cost by another 45,000



Your consultant gave you excellent advice. Hybrid MPPT inverters are a man made wonder and can save you loads on KPLC. The system seems adequate to me...keeping in mind that during blackouts you will not be using 100% of daily usage...solar during blackout is just a stopgap measure if you have KPLC so no need to get a huge costly system which you will not use optimally. Good luck and update us on how things go.


As a back up system in case kplc fails, its ok. As the main system its not adequate to provide 4000 watts daily. You will fid yourself using kplc for a portion of the time and this will greatly reduce your battery life because each day you will fully discharge your batteries to maximum.

Also note that a 2400 watt inverter cannot run any of those mentioned items simultaneously, it will have to be one by one. A water heater instant shower alone can be 2500 watts, microwave alone can be 2000 watts. So you may not manage to have 2 people shower off solar or have someone switch on microwave while another is ironing etc etc. So judicious use of appliances is called for here.

As a lights only backup, it is adequate. To run those appliances, I highly doubt it.


Please remember how a hybrid all in one MPPT inverter works;

- It can draw juice from the panels AND KPLC at the same time and optimise depending on settings
- It has a crazy amount of other settings including exactly how much % draw down you want on your batteries before KPLC kicks in.
-Can even draw juice from a generator or work with no batteries whatsoever depending on model.
- Has so many other features that would take over an hour to expound upon.

winmak was quite clear that the system would use KPLC backup during periods of heavy use.

These hybrid inverters are a man made wonder as I said before. Once you go over 1KW in solar size they are the no-brainer option for domestic use. I am yet to need such a system but when I do, will definitely go the winmak way.



The system is ok as a backup for when KPLC fails. It will however not take you any where near " NEAR TOTAL OFFGRID" as suggested for a 4kw daily energy use. Numbers dont lie.
They must find it difficult....... those who have taken authority as the truth, rather than truth as the authority. -G. Massey.
tom_boy
#82 Posted : Monday, December 21, 2020 2:13:24 PM
Rank: Member


Joined: 2/20/2007
Posts: 767
@ winmark, lets do some simple Math. Your needs are 4000 watts a day. 2pcs 12 200ah batteries will give you 2400 watts of usable power. (lead acid batteries can only be discharged upto 50%). Of tis 2400, assume 10% will be lost through the wiring and inverter losses. So in real fact, assuming batteries are fully charged by sun down, you only realistically have 2200 watts available for use.

An instant shower is usually rated 2500 watts. If you shower for 10 minutes you will use about 400 watts. If 4 people shower for 10 minutes each, that is 1600 watts gone. Hata hujaweka lighting, ironing, microwave. So, your systems as planned is probably only good for lighting and TV, phone charging. If house is already wired, you may need to find a way to seperate sockets so you have some that are solar and some that are KPLC. Is this worth it? I dont know.

Even if its a hibreed inverter, as long as you end up using KPLC to charge the batteries, you will not be off grid and you will even pay more eventually due to electricity losses when converting AC to DC and then back to AC. Also, Lead acid batteries are not designed for constant charge and discharge, several cycles a day, you will lose those batteries within a year.
They must find it difficult....... those who have taken authority as the truth, rather than truth as the authority. -G. Massey.
amorphous
#83 Posted : Tuesday, December 22, 2020 10:56:26 AM
Rank: Member


Joined: 5/15/2019
Posts: 677
Location: planet earth
tom_boy wrote:
@ winmark, lets do some simple Math. Your needs are 4000 watts a day. 2pcs 12 200ah batteries will give you 2400 watts of usable power. (lead acid batteries can only be discharged upto 50%). Of tis 2400, assume 10% will be lost through the wiring and inverter losses. So in real fact, assuming batteries are fully charged by sun down, you only realistically have 2200 watts available for use.

An instant shower is usually rated 2500 watts. If you shower for 10 minutes you will use about 400 watts. If 4 people shower for 10 minutes each, that is 1600 watts gone. Hata hujaweka lighting, ironing, microwave. So, your systems as planned is probably only good for lighting and TV, phone charging. If house is already wired, you may need to find a way to seperate sockets so you have some that are solar and some that are KPLC. Is this worth it? I dont know.

Even if its a hibreed inverter, as long as you end up using KPLC to charge the batteries, you will not be off grid and you will even pay more eventually due to electricity losses when converting AC to DC and then back to AC. Also, Lead acid batteries are not designed for constant charge and discharge, several cycles a day, you will lose those batteries within a year.



1. 4000 watt*hours* used per day
2. 2pcs of 12V 200ah batteries *in series* = 2* 12*X200= 4800 Watt*hours* available power when 100% charged
3. With 50% battery drawdown provision = 2400 watt *hours* available power meaning 2 more 200ah batteries need to be added for a total capacity of 9600Wh.
4. 4*275W panels = 1100W charging power
5. Sun hours in Kenya (very conservative estimate) = 8
6. Charging capacity of panels per day = 8800 Watt*hours* per day. For the battery bank of 4*12*200ah to be fully charged daily, he would need to add one more panel.
7. KPLC can kick in during cloudy/rainy days or when daily use surges past 4600 watt hours.

The only modification I see he needs is that his hybrid inverter must be scaled up to 4Kw to handle a full load, ama? That way on very sunny and long days, it can charge the battery bank 100% as well as power the house on a full load directly once the batteries are fully charged

What am I missing/misunderstanding or miscalculating here? Suggestions, criticisms and modifications welcome.

Let us continue to learn in order to improve on our solar knowledge. Thanks guys.

Age and family mellows us all over time
sqft
#84 Posted : Tuesday, December 22, 2020 12:19:22 PM
Rank: Veteran


Joined: 1/10/2015
Posts: 961
Location: Kenya
The easiest and cheapest way to go off grid. Install the following:

1. Solar PV system to power TV, Radio, fridge, charge phone, lighting (2x 200ah batteries will do) - cost of system 4x125w panels, charge controller, inverter, batteries = 90k.
2. Solar water heater to take care of hot showers (200l system about 80k)
3. Small 2.5 kva generator for any extra power needs eg ironing, baking in the oven, submersible/water pump, washing machine etc (cost about 30k and consumes about 1 ltr fuel per hr i.e 100bob).

Total off-grid cost about 200k and you say GOODBYE to KPLC FOREVER.

NB: one can do away with the microwave and use other means to warm food
Proverbs 13:11 Dishonest money dwindles away, but whoever gathers money little by little makes it grow.
tom_boy
#85 Posted : Tuesday, December 22, 2020 12:32:16 PM
Rank: Member


Joined: 2/20/2007
Posts: 767
amorphous wrote:
tom_boy wrote:
@ winmark, lets do some simple Math. Your needs are 4000 watts a day. 2pcs 12 200ah batteries will give you 2400 watts of usable power. (lead acid batteries can only be discharged upto 50%). Of tis 2400, assume 10% will be lost through the wiring and inverter losses. So in real fact, assuming batteries are fully charged by sun down, you only realistically have 2200 watts available for use.

An instant shower is usually rated 2500 watts. If you shower for 10 minutes you will use about 400 watts. If 4 people shower for 10 minutes each, that is 1600 watts gone. Hata hujaweka lighting, ironing, microwave. So, your systems as planned is probably only good for lighting and TV, phone charging. If house is already wired, you may need to find a way to seperate sockets so you have some that are solar and some that are KPLC. Is this worth it? I dont know.

Even if its a hibreed inverter, as long as you end up using KPLC to charge the batteries, you will not be off grid and you will even pay more eventually due to electricity losses when converting AC to DC and then back to AC. Also, Lead acid batteries are not designed for constant charge and discharge, several cycles a day, you will lose those batteries within a year.



1. 4000 watt*hours* used per day I agree
2. 2pcs of 12V 200ah batteries *in series* = 2* 12*X200= 4800 Watt*hours* available power when 100% charged I agree
3. With 50% battery drawdown provision = 2400 watt *hours* available power meaning 2 more 200ah batteries need to be added for a total capacity of 9600Wh. I agree
4. 4*275W panels = 1100W charging power I agree but this is during PEAK sun hours
5. Sun hours in Kenya (very conservative estimate) = 8 Most people work with 6hrs of PEAK sun to be on the safe side
6. Charging capacity of panels per day = 8800 Watt*hours* per day. For the battery bank of 4*12*200ah to be fully charged daily, he would need to add one more panel. No need for extra panel if using MPPT charge controller. Remember draw down is 4800 watts meaning will only need to top this up within 5 hrs. This calls for a charging current of 80amps per hr from the panels. The 150v 100amp mppt charge controller will handle this. Make sure panels are connected in a manner to maximize mppt current generation, but do not exceed the 150v input voltage of the mppt. Wiring has to be thick enough to take this high current. Alternative is to switch to a 24 or 48v system but will need a new inverter.
7. KPLC can kick in during cloudy/rainy days or when daily use surges past 8800 watt hours. you mean surges past 4800 watts. Idealy you should not exceed 50% discharge of the 4 batteries.

The only modification I see he needs is that his hybrid inverter must be scaled up to 4Kw to handle a full load, ama? That way on very sunny and long days, it can charge the battery bank 100% as well as power the house on a full load directly once the batteries are fully charged No need to increase inverter rating unless there are loads that will exceed the 2400 watts. I checked and discovered that instant shower is rated at 4000 watts, so YES, if running showers is part of the program, then minimum 4.5kw inverter is needed and maybe more if you intend to run an instant shower and say the lights and microwave simultaneously. This will add to cost.

What am I missing/misunderstanding or miscalculating here? Suggestions, criticisms and modifications welcome.

Let us continue to learn in order to improve on our solar knowledge. Thanks guys.

This system as designed by @amorphous will still not get you Offgrid in the true sense of the word. It will be an excellent back up sytem but far from offgrid. To begin with, forget running hot showers on solar unless one puts in solar water heating specifically. That will simplify your life completely. With showers out of the way, also forget using the system for any kind of prolonged heating, prolonged ironing like for more than 30 minutes at a time, cooking etc. These will still be KPLC functions.
If you remove all these, you are left with lights (ensure they are high efficiency LED lights), TV, fridge(depending on its size and efficiency), phone charging and small kitchen appliances that you use for a few seconds or minutes in a day. I think this system should handle this even with the 2400watt inverter as long as you do not run 2 heavy loads simultaneously, like an iron and a microwave.





They must find it difficult....... those who have taken authority as the truth, rather than truth as the authority. -G. Massey.
amorphous
#86 Posted : Tuesday, December 22, 2020 1:07:50 PM
Rank: Member


Joined: 5/15/2019
Posts: 677
Location: planet earth
sqft wrote:
The easiest and cheapest way to go off grid. Install the following:

1. Solar PV system to power TV, Radio, fridge, charge phone, lighting (2x 200ah batteries will do) - cost of system 4x150w panels, charge controller, inverter, batteries = 90k.
2. Solar water heater to take care of hot showers (200l system about 80k)
3. Small 2.5 kva generator for any extra power needs eg ironing, baking in the oven, submersible/water pump, washing machine etc (cost about 30k and consumes about 1 ltr fuel per hr i.e 100bob).

Total off-grid cost about 200k and you say GOODBYE to KPLC FOREVER.

NB: one can do away with the microwave and use other means to warm food



hehehehehe I like this! I like a minimalist approach to solar; it shouldn't be the type of system one should depend on to power 100% of their full load in Nairobi (if the site is in the boondocks) but rather something to power the basics 24/7. In the city...it should just be a backup. Solar water heater is a wonderful idea. No need for instant showers and heaters that draw needless juice. Microwave has been a no no for me even with KPLC. I read the studies on the harmful effects on foods and said never again around 2010 or so. Even at restaurants if I see them heading to warm my samosa in a microwave I shout a loud NO.
Age and family mellows us all over time
amorphous
#87 Posted : Tuesday, December 22, 2020 1:14:13 PM
Rank: Member


Joined: 5/15/2019
Posts: 677
Location: planet earth
tom_boy wrote:
amorphous wrote:
tom_boy wrote:
@ winmark, lets do some simple Math. Your needs are 4000 watts a day. 2pcs 12 200ah batteries will give you 2400 watts of usable power. (lead acid batteries can only be discharged upto 50%). Of tis 2400, assume 10% will be lost through the wiring and inverter losses. So in real fact, assuming batteries are fully charged by sun down, you only realistically have 2200 watts available for use.

An instant shower is usually rated 2500 watts. If you shower for 10 minutes you will use about 400 watts. If 4 people shower for 10 minutes each, that is 1600 watts gone. Hata hujaweka lighting, ironing, microwave. So, your systems as planned is probably only good for lighting and TV, phone charging. If house is already wired, you may need to find a way to seperate sockets so you have some that are solar and some that are KPLC. Is this worth it? I dont know.

Even if its a hibreed inverter, as long as you end up using KPLC to charge the batteries, you will not be off grid and you will even pay more eventually due to electricity losses when converting AC to DC and then back to AC. Also, Lead acid batteries are not designed for constant charge and discharge, several cycles a day, you will lose those batteries within a year.



1. 4000 watt*hours* used per day I agree
2. 2pcs of 12V 200ah batteries *in series* = 2* 12*X200= 4800 Watt*hours* available power when 100% charged I agree
3. With 50% battery drawdown provision = 2400 watt *hours* available power meaning 2 more 200ah batteries need to be added for a total capacity of 9600Wh. I agree
4. 4*275W panels = 1100W charging power I agree but this is during PEAK sun hours
5. Sun hours in Kenya (very conservative estimate) = 8 Most people work with 6hrs of PEAK sun to be on the safe side
6. Charging capacity of panels per day = 8800 Watt*hours* per day. For the battery bank of 4*12*200ah to be fully charged daily, he would need to add one more panel. No need for extra panel if using MPPT charge controller. Remember draw down is 4800 watts meaning will only need to top this up within 5 hrs. This calls for a charging current of 80amps per hr from the panels. The 150v 100amp mppt charge controller will handle this. Make sure panels are connected in a manner to maximize mppt current generation, but do not exceed the 150v input voltage of the mppt. Wiring has to be thick enough to take this high current. Alternative is to switch to a 24 or 48v system but will need a new inverter.
7. KPLC can kick in during cloudy/rainy days or when daily use surges past 8800 watt hours. you mean surges past 4800 watts. Idealy you should not exceed 50% discharge of the 4 batteries.

The only modification I see he needs is that his hybrid inverter must be scaled up to 4Kw to handle a full load, ama? That way on very sunny and long days, it can charge the battery bank 100% as well as power the house on a full load directly once the batteries are fully charged No need to increase inverter rating unless there are loads that will exceed the 2400 watts. I checked and discovered that instant shower is rated at 4000 watts, so YES, if running showers is part of the program, then minimum 4.5kw inverter is needed and maybe more if you intend to run an instant shower and say the lights and microwave simultaneously. This will add to cost.

What am I missing/misunderstanding or miscalculating here? Suggestions, criticisms and modifications welcome.

Let us continue to learn in order to improve on our solar knowledge. Thanks guys.

This system as designed by @amorphous will still not get you Offgrid in the true sense of the word. It will be an excellent back up sytem but far from offgrid. To begin with, forget running hot showers on solar unless one puts in solar water heating specifically. That will simplify your life completely. With showers out of the way, also forget using the system for any kind of prolonged heating, prolonged ironing like for more than 30 minutes at a time, cooking etc. These will still be KPLC functions.
If you remove all these, you are left with lights (ensure they are high efficiency LED lights), TV, fridge(depending on its size and efficiency), phone charging and small kitchen appliances that you use for a few seconds or minutes in a day. I think this system should handle this even with the 2400watt inverter as long as you do not run 2 heavy loads simultaneously, like an iron and a microwave.





Thanks for the feedback. I am learning a lot!
All this just confirms to me that a basic 2kw system with an all in one Hybrid MPPT inverter will be perfect for my cabin in the woods. I am dying to buy one of those all in one hybrid units to test and see how they work. Nothing beats experiential learning IMHO.
Age and family mellows us all over time
tom_boy
#88 Posted : Tuesday, December 22, 2020 4:11:10 PM
Rank: Member


Joined: 2/20/2007
Posts: 767
amorphous wrote:
tom_boy wrote:
amorphous wrote:
tom_boy wrote:
@ winmark, lets do some simple Math. Your needs are 4000 watts a day. 2pcs 12 200ah batteries will give you 2400 watts of usable power. (lead acid batteries can only be discharged upto 50%). Of tis 2400, assume 10% will be lost through the wiring and inverter losses. So in real fact, assuming batteries are fully charged by sun down, you only realistically have 2200 watts available for use.

An instant shower is usually rated 2500 watts. If you shower for 10 minutes you will use about 400 watts. If 4 people shower for 10 minutes each, that is 1600 watts gone. Hata hujaweka lighting, ironing, microwave. So, your systems as planned is probably only good for lighting and TV, phone charging. If house is already wired, you may need to find a way to seperate sockets so you have some that are solar and some that are KPLC. Is this worth it? I dont know.

Even if its a hibreed inverter, as long as you end up using KPLC to charge the batteries, you will not be off grid and you will even pay more eventually due to electricity losses when converting AC to DC and then back to AC. Also, Lead acid batteries are not designed for constant charge and discharge, several cycles a day, you will lose those batteries within a year.



1. 4000 watt*hours* used per day I agree
2. 2pcs of 12V 200ah batteries *in series* = 2* 12*X200= 4800 Watt*hours* available power when 100% charged I agree
3. With 50% battery drawdown provision = 2400 watt *hours* available power meaning 2 more 200ah batteries need to be added for a total capacity of 9600Wh. I agree
4. 4*275W panels = 1100W charging power I agree but this is during PEAK sun hours
5. Sun hours in Kenya (very conservative estimate) = 8 Most people work with 6hrs of PEAK sun to be on the safe side
6. Charging capacity of panels per day = 8800 Watt*hours* per day. For the battery bank of 4*12*200ah to be fully charged daily, he would need to add one more panel. No need for extra panel if using MPPT charge controller. Remember draw down is 4800 watts meaning will only need to top this up within 5 hrs. This calls for a charging current of 80amps per hr from the panels. The 150v 100amp mppt charge controller will handle this. Make sure panels are connected in a manner to maximize mppt current generation, but do not exceed the 150v input voltage of the mppt. Wiring has to be thick enough to take this high current. Alternative is to switch to a 24 or 48v system but will need a new inverter.
7. KPLC can kick in during cloudy/rainy days or when daily use surges past 8800 watt hours. you mean surges past 4800 watts. Idealy you should not exceed 50% discharge of the 4 batteries.

The only modification I see he needs is that his hybrid inverter must be scaled up to 4Kw to handle a full load, ama? That way on very sunny and long days, it can charge the battery bank 100% as well as power the house on a full load directly once the batteries are fully charged No need to increase inverter rating unless there are loads that will exceed the 2400 watts. I checked and discovered that instant shower is rated at 4000 watts, so YES, if running showers is part of the program, then minimum 4.5kw inverter is needed and maybe more if you intend to run an instant shower and say the lights and microwave simultaneously. This will add to cost.

What am I missing/misunderstanding or miscalculating here? Suggestions, criticisms and modifications welcome.

Let us continue to learn in order to improve on our solar knowledge. Thanks guys.

This system as designed by @amorphous will still not get you Offgrid in the true sense of the word. It will be an excellent back up sytem but far from offgrid. To begin with, forget running hot showers on solar unless one puts in solar water heating specifically. That will simplify your life completely. With showers out of the way, also forget using the system for any kind of prolonged heating, prolonged ironing like for more than 30 minutes at a time, cooking etc. These will still be KPLC functions.
If you remove all these, you are left with lights (ensure they are high efficiency LED lights), TV, fridge(depending on its size and efficiency), phone charging and small kitchen appliances that you use for a few seconds or minutes in a day. I think this system should handle this even with the 2400watt inverter as long as you do not run 2 heavy loads simultaneously, like an iron and a microwave.





Thanks for the feedback. I am learning a lot!
All this just confirms to me that a basic 2kw system with an all in one Hybrid MPPT inverter will be perfect for my cabin in the woods. I am dying to buy one of those all in one hybrid units to test and see how they work. Nothing beats experiential learning IMHO.


Personally, I would not do a hybrid inverter (by this I mean a unit that acts as both charge controller and inverter). I think it only makes alot of sense if you can send excess power back to KPLC which you cannot do in Kenya (for the average individual).

I would get a seperate charge controller that can utilise different power sources like solar, generator or grid to charge the battery. Then get a seperate inverter. I would likely spend more money on panels and charge controller and less on batteries and inverter in the beginning. Its easy to upgrade batteries and inverter later on. Upgrading panels will require going up to do roof work. Upgrading charge controller means you need more power from the roof meaning more roof work and /or changing configuration of old panels to accomodate a new charge controller. Thats just my reasoning after doing research on these things.
They must find it difficult....... those who have taken authority as the truth, rather than truth as the authority. -G. Massey.
amorphous
#89 Posted : Wednesday, December 23, 2020 5:50:47 PM
Rank: Member


Joined: 5/15/2019
Posts: 677
Location: planet earth
winmak wrote:
kayhara wrote:
back-up muhimu, I started mine with the vispra 1000 watt inverter charger and the 200ah gel battery from sollatek, I charge with kplc, I will not interfere with that system which I think is under used it powers tv 70 watts, ceiling fan 75 watts, router 7 watts, bulbs 40 watts hifi 35 watts.
I am getting the vispra 2000 watts inverter charger and 2x 200 ah gel batteries and 2x 350 watt Schneider solar panels, this will keep my freezer, fridge, 4 ceiling fans, an induction cooker can continue running, also the 1000 watt set-up will charge from this, only my oven, microwave, shower, iron and kettle will be on kplc.


Good stuff...

My 'solar consultant' has suggested to me this for a mansionnette with avg use of 4kWh/day, heaviest appliances being 3 shower heaters, fridge, iron box, water pump and microwave:

1. 4 pannels of 275 watts
2. 2 batteries (cant remember the specs)
3. 2.4kW hybrid inverter (to be done in a way such that it can automatically draw power from KPLC once the batteries go lower than a preset figure)

This comes closest to near total off grid with KPLC as the back up during periods of heavy use (which he advices I do during the day at full sun glow - like water pumping and ironing... and try to stagger usage so that I dont have the heavy users running at the same time... otherwise I require a 3kW inverter which pushes the cost by another 45,000




After watching this video..I want a hybrid baaad! I love how it bypasses the fully charged battery and powers the grid nyweee directly. Truly a wonder to behold Applause smile
Age and family mellows us all over time
madhaquer
#90 Posted : Thursday, December 24, 2020 1:10:33 PM
Rank: Member


Joined: 11/10/2010
Posts: 281
Location: Nairobi
When planning to go off grid or reduce your power bill, the approach is different from just looking for a backup to KPLC instabilities. This point is critical in determining the overall cost of the system.

If you only need a backup system, then what amorphous recommends is perfect. You just need something to charge phones, lighting and very basic use of power. The rest like microwave oven, water heating etc can wait.

When going off grid or planning to move in that direction, the planning requirements are long term and in some cases lifestyle needs to be adjusted. In this scenario, the loading requirements determine the battery dimension which determines the bulk of the cost.

Personally i recommend solar water heating solutions for all cases. A solar water heater when planned for properly, guarantees hot water throughout the household and some storage attached to that too.
amorphous
#91 Posted : Thursday, December 24, 2020 2:08:16 PM
Rank: Member


Joined: 5/15/2019
Posts: 677
Location: planet earth
madhaquer wrote:
When planning to go off grid or reduce your power bill, the approach is different from just looking for a backup to KPLC instabilities. This point is critical in determining the overall cost of the system.

If you only need a backup system, then what amorphous recommends is perfect. You just need something to charge phones, lighting and very basic use of power. The rest like microwave oven, water heating etc can wait.

When going off grid or planning to move in that direction, the planning requirements are long term and in some cases lifestyle needs to be adjusted. In this scenario, the loading requirements determine the battery dimension which determines the bulk of the cost.

Personally i recommend solar water heating solutions for all cases. A solar water heater when planned for properly, guarantees hot water throughout the household and some storage attached to that too.


Good stuff! I read somewhere that water heating consumes a whopping 70% of domestic power in some cases. I definitely need to invest big in solar water heaters.
Age and family mellows us all over time
amorphous
#92 Posted : Saturday, December 26, 2020 9:13:56 AM
Rank: Member


Joined: 5/15/2019
Posts: 677
Location: planet earth
The only video on hybrid solar inverters you will ever need to watch.



Simply amazing, I will have to get this device soonest.
Age and family mellows us all over time
madhaquer
#93 Posted : Monday, December 28, 2020 8:27:50 PM
Rank: Member


Joined: 11/10/2010
Posts: 281
Location: Nairobi
The best decision i made when doing my house was double piping to all taps. I installed mixers and a solar water panel with a 300L tank attached to it.

Gives a free choice to use cold, hot or warm water. No need for instant showers.
amorphous
#94 Posted : Tuesday, December 29, 2020 8:50:17 AM
Rank: Member


Joined: 5/15/2019
Posts: 677
Location: planet earth
madhaquer wrote:
The best decision i made when doing my house was double piping to all taps. I installed mixers and a solar water panel with a 300L tank attached to it.

Gives a free choice to use cold, hot or warm water. No need for instant showers.


Nice! I have also double piped and made provision for solar water heater but yet to install. Do you have an overhead tank higher than the roof? I don't and I'm told I will need a booster pump as a result. Any opinion on this?
Age and family mellows us all over time
sqft
#95 Posted : Tuesday, December 29, 2020 12:31:25 PM
Rank: Veteran


Joined: 1/10/2015
Posts: 961
Location: Kenya
amorphous wrote:
sqft wrote:
The easiest and cheapest way to go off grid. Install the following:

1. Solar PV system to power TV, Radio, fridge, charge phone, lighting (2x 200ah batteries will do) - cost of system 4x150w panels, charge controller, inverter, batteries = 90k.
2. Solar water heater to take care of hot showers (200l system about 80k)
3. Small 2.5 kva generator for any extra power needs eg ironing, baking in the oven, submersible/water pump, washing machine etc (cost about 30k and consumes about 1 ltr fuel per hr i.e 100bob).

Total off-grid cost about 200k and you say GOODBYE to KPLC FOREVER.

NB: one can do away with the microwave and use other means to warm food



hehehehehe I like this! I like a minimalist approach to solar; it shouldn't be the type of system one should depend on to power 100% of their full load in Nairobi (if the site is in the boondocks) but rather something to power the basics 24/7. In the city...it should just be a backup. Solar water heater is a wonderful idea. No need for instant showers and heaters that draw needless juice. Microwave has been a no no for me even with KPLC. I read the studies on the harmful effects on foods and said never again around 2010 or so. Even at restaurants if I see them heading to warm my samosa in a microwave I shout a loud NO.


That is the MOST COST EFFECTIVE setup you will ever need to go off grid and it takes care of 100% of your needs.

You could also get a direct drive solar fridge that connects directly to the solar panel without the need of a battery. This would reduce expense on solar batteries greatly. Direct drive Solar fridge costs 96k from sollatek and includes a free panel.



Proverbs 13:11 Dishonest money dwindles away, but whoever gathers money little by little makes it grow.
madhaquer
#96 Posted : Tuesday, December 29, 2020 1:05:34 PM
Rank: Member


Joined: 11/10/2010
Posts: 281
Location: Nairobi
amorphous wrote:
madhaquer wrote:
The best decision i made when doing my house was double piping to all taps. I installed mixers and a solar water panel with a 300L tank attached to it.

Gives a free choice to use cold, hot or warm water. No need for instant showers.


Nice! I have also double piped and made provision for solar water heater but yet to install. Do you have an overhead tank higher than the roof? I don't and I'm told I will need a booster pump as a result. Any opinion on this?


I don't have an overhead tank apart from the solar tank+panel itself.
I have a booster pump that pumps my water from ground based tank to that tank and others in the ceiling. The council water supply also goes up to the tanks when the pressure is right.
amorphous
#97 Posted : Tuesday, December 29, 2020 2:54:40 PM
Rank: Member


Joined: 5/15/2019
Posts: 677
Location: planet earth
sqft wrote:

That is the MOST COST EFFECTIVE setup you will ever need to go off grid and it takes care of 100% of your needs.

You could also get a direct drive solar fridge that connects directly to the solar panel without the need of a battery. This would reduce expense on solar batteries greatly. Direct drive Solar fridge costs 96k from sollatek and includes a free panel.





Asante sana for this!
Age and family mellows us all over time
amorphous
#98 Posted : Tuesday, December 29, 2020 2:56:13 PM
Rank: Member


Joined: 5/15/2019
Posts: 677
Location: planet earth
madhaquer wrote:
amorphous wrote:
madhaquer wrote:
The best decision i made when doing my house was double piping to all taps. I installed mixers and a solar water panel with a 300L tank attached to it.

Gives a free choice to use cold, hot or warm water. No need for instant showers.


Nice! I have also double piped and made provision for solar water heater but yet to install. Do you have an overhead tank higher than the roof? I don't and I'm told I will need a booster pump as a result. Any opinion on this?


I don't have an overhead tank apart from the solar tank+panel itself.
I have a booster pump that pumps my water from ground based tank to that tank and others in the ceiling. The council water supply also goes up to the tanks when the pressure is right.


Nice Applause I will work on getting this installed post haste.
Age and family mellows us all over time
amorphous
#99 Posted : Wednesday, December 30, 2020 8:26:21 AM
Rank: Member


Joined: 5/15/2019
Posts: 677
Location: planet earth
Moneysaver. Maridadi sana. Looks very sleek and nice. Depending on orientation to the sun, however, I want mine hidden in the back of the roof rather than mbele like I see many doing. I like that it comes with a panel with which you can monitor things without having to climb the roof.



Age and family mellows us all over time
amorphous
#100 Posted : Saturday, January 09, 2021 4:10:25 PM
Rank: Member


Joined: 5/15/2019
Posts: 677
Location: planet earth
We had a blackout juzi jioni and there I was enjoying my well lit sitting room, laptop and TV running shwaaaaaaa bila msukosuko wowote for hours while I sipped my coffee. Solar backup na beautiful thing -oo. Voltage on the battery was about 12.8 and only went down to 12.5 after all that usage.
Age and family mellows us all over time
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