diy solar

diy solar

Hello, newbie here and as usual looking for advice.

Blue-q8

New Member
Joined
Feb 6, 2023
Messages
10
Location
Kuwait
Hello, I just joined and looking for advice on building my first DIY solar energy powered lights for the lawn outside, i hope someone can direct me in the right direction (or thread), this is what i have in plan:

35amp VRLA battery or similar AGM.
100 watt solar panel.
Victron Energy BlueSolar MPPT 100V 15 amp 12/24-Volt Solar Charge Controller.
LED lights and Auto On Off Photocell Light Switch.

But since I'm new to this, I have no idea if my setup is right, and if my system is correct, and please keep in mind I'd like to use Victron Energy controller since I've their products on my car.
 
How much total power do the lights consume?
how long do you want to run them per day?
Hi, I'm planning to use old KC Lights Cyclone V2 that I removed from previous vehicle and didn't use since then, this is the specs:

Amp Draw: 0.42 a
Light Temperature: 5000K
Lumens: 600lm
Wattage: 5W
Voltage: 9V-16V

I'll use 6 lights, their power consumption is very low when i had them on my previous overlander, so now I'll use them to illuminate my lawn.

They might be on for 6 hours in summer and 9 hours in winter.
 
5W * 6 * 9h = 270Wh

270Wh /12V = 22.5Ah

Your battery has only 17.5Ah of usable capacity, so it's insufficient for the 9h requirement.

If the 100W panel is mounted flat, it will fall far short in winter. You're lucky to get 40% of rated power on a flat mounted panel in Winter.
 
5W * 6 * 9h = 270Wh

270Wh /12V = 22.5Ah

Your battery has only 17.5Ah of usable capacity, so it's insufficient for the 9h requirement.

If the 100W panel is mounted flat, it will fall far short in winter. You're lucky to get 40% of rated power on a flat mounted panel in Winter.
Oh, what's your recommendation for the setup please? I would really appreciate the help, and what size solar panel i can use with Victron Energy BlueSolar MPPT 100V 15 amp 12/24-Volt Solar Charge Controller?
 
Oh, what's your recommendation for the setup please? I would really appreciate the help, and what size solar panel i can use with Victron Energy BlueSolar MPPT 100V 15 amp 12/24-Volt Solar Charge Controller?

At least 50Ah battery.

A second 100W panel, or a single larger panel > 200W. The controller can handle two of those 100W panels in series, and will only use what it can. As long as you don't exceed 100V PV input and 15A PV input, the controller will be fine. It will output a maximum of 220W on a 12V system.

Maybe spring for the smartsolar 100/15... the BT w/VictronConnect is really nice.
 
At least 50Ah battery.

A second 100W panel, or a single larger panel > 200W. The controller can handle two of those 100W panels in series, and will only use what it can. As long as you don't exceed 100V PV input and 15A PV input, the controller will be fine. It will output a maximum of 220W on a 12V system.

Maybe spring for the smartsolar 100/15... the BT w/VictronConnect is really nice.

That's great, much appreciated, I've made my purchase list, which fuse size should i use? 10amp or 20amp? And wire size 10awg or 12awg?

I'll go for the SmartSolar 100/15 with 160w solar panel and perhaps a simple on/off switch instead of photocell light switch, depend on the battery size and weight.
 
160W probably won't cover it.

The load ports of the smart solar 100/15 provide some additional protection:

1675708485787.png

i.e., you can power the lights from the load ports, and if the voltage drops below 11.8V, it will shut them off until the controller charges the battery to above 14.0V. They will turn back on and stay on until 11.8V is hit again.

10 or 12awg is fine. Fuse/breaker for 25% more current than the wire's rating.
 
160W probably won't cover it.

The load ports of the smart solar 100/15 provide some additional protection:

View attachment 133582

i.e., you can power the lights from the load ports, and if the voltage drops below 11.8V, it will shut them off until the controller charges the battery to above 14.0V. They will turn back on and stay on until 11.8V is hit again.

10 or 12awg is fine. Fuse/breaker for 25% more current than the wire's rating.
Thank you very much, i'm starting to walk in the right direction hopefully, you're information is most helpful, do you recommend any section of the forums where i can view similar DIYs please?
 
Thank you very much, i'm starting to walk in the right direction hopefully, you're information is most helpful, do you recommend any section of the forums where i can view similar DIYs please?

Not that I know of.

All DIYs come down to the same formula:

What are my daily energy needs?
What is my daily available solar energy?
How many day's of autonomy do I want (most do one day)?

That's what we've done here.
 
Not that I know of.

All DIYs come down to the same formula:

What are my daily energy needs?
What is my daily available solar energy?
How many day's of autonomy do I want (most do one day)?

That's what we've done here.
Thank you very much for your help, I'll start my project once i'm back from my travel, and i'll continue reading and learning about it.
 
KC Lights Cyclone V2


Wattage: 5W

I'll use 6 lights


Can you get by with fewer lights, or select a lower wattage light?
I think those are meant as driving lights, not necessarily optimum for floodlighting the lawn.

35amp VRLA battery or similar AGM.

Good for 300 to 700 deep (50% to 70%) cycles, then you buy replacements.
Does that fit your needs?
If shallow cycled 10% to 15%, might last 10 years.

Lithium gives 5x the cycle life. Must not be charged below freezing.

100 watt solar panel.
Victron Energy BlueSolar MPPT 100V 15 amp 12/24-Volt Solar Charge Controller.

Does SCC have battery temperature sensor? That helps greatly for lead-acid if temperature range is large.

100V input probably supports three of those PV panels in series. But, 15A x 12V = 180W.
Good fit for 2 in series. Maybe 2s2p of two orientations.

35 Ah VRLA probably wants 7A charge. 15A may be too much, but some brands can take it. Bigger battery can take it.

PV panels 2p of two orientations would maintain flat charge for more hours, better for lead-acid and would fit your 35 Ah battery's charge rate.
 

Can you get by with fewer lights, or select a lower wattage light?
I think those are meant as driving lights, not necessarily optimum for floodlighting the lawn.



Good for 300 to 700 deep (50% to 70%) cycles, then you buy replacements.
Does that fit your needs?
If shallow cycled 10% to 15%, might last 10 years.

Lithium gives 5x the cycle life. Must not be charged below freezing.



Does SCC have battery temperature sensor? That helps greatly for lead-acid if temperature range is large.

100V input probably supports three of those PV panels in series. But, 15A x 12V = 180W.
Good fit for 2 in series. Maybe 2s2p of two orientations.

35 Ah VRLA probably wants 7A charge. 15A may be too much, but some brands can take it. Bigger battery can take it.

PV panels 2p of two orientations would maintain flat charge for more hours, better for lead-acid and would fit your 35 Ah battery's charge rate.
Hello, Yes I might go with 4 instead of 6 lights, they have fogged lens for flood, i used them to illuminate the are at night, I wanted to use them since i have them and i know their performance.

As for batteries I'll have to check the shops, because I have Power Sonic PS-12550 battery installed on my car to power my fridge and auxiliary lights when i go overlanding, and i remember seeing a 35amp version Power Sonic PS-12350.
Lithium in not an option for 2 reasons, it's hard to get in my country, and the temperature gets extremely high in my country (50c/120f +/-range).

I think the SCC doesn't have temperature sensor, but Victron Energy sells Smart Battery Sense which monitor both voltage and temperature to optimize charging.

Any recommendation for solar panels? wattage and connection, I have no knowledge about it, i'm sailing into new seas.
 
Panel connection, #1 rule is calculate Voc of the string adjusted for your location's record coldest temperature, and never exceed SCC max allowed.

Panels, we can pay $0.10 to $1.00/W.
New panels may be liquidated from spares bought for a large install. used, can be from solar farms.
Some brands have severe degradation rates, others are top quality and can be a bargain a few years old.

I still suggest seeing if you can light your yard with 5W of LED rather than 20W to 30W. I used 35W and 70W HPS; LED should reduce consumption significantly.

AGM is best for low maintenance and freezing weather. You need temperature adjusted voltages to charge properly in your environment. Limit DoD to what prevents freezing in your coldest temperatures (technical data has tables.) Large enough capacity to last a decade doesn't cost more $$ per kWh of cycle life, just more $$ up front.

FLA is cheaper and/or longer lasting. Golf cart batteries could be the bargain way to go, more maintenance thought. Catalytic recombination caps & automatic watering are options.
 
Panel connection, #1 rule is calculate Voc of the string adjusted for your location's record coldest temperature, and never exceed SCC max allowed.

Panels, we can pay $0.10 to $1.00/W.
New panels may be liquidated from spares bought for a large install. used, can be from solar farms.
Some brands have severe degradation rates, others are top quality and can be a bargain a few years old.

I still suggest seeing if you can light your yard with 5W of LED rather than 20W to 30W. I used 35W and 70W HPS; LED should reduce consumption significantly.

AGM is best for low maintenance and freezing weather. You need temperature adjusted voltages to charge properly in your environment. Limit DoD to what prevents freezing in your coldest temperatures (technical data has tables.) Large enough capacity to last a decade doesn't cost more $$ per kWh of cycle life, just more $$ up front.

FLA is cheaper and/or longer lasting. Golf cart batteries could be the bargain way to go, more maintenance thought. Catalytic recombination caps & automatic watering are options.

Hello, can you please explain the following shortforms for me please:
and 70W HPS
Limit DoD

My lawn is short distance between my car parking shade and home, that's the place i want illuminated at night, I'm still considering what type of switch should I use, photocell light switch if i want them ON from dusk till dawn, simple On/Off switch so i can use them when i leave/come to my house, or now i'm thinking about a motion sensor switch.

Coldest temperature in winter may reach (8c/46f -/+), and it's sunny all year around, we rarely get clouds for 3 or 4 consecutive days.
 
I have yard lights with 70 watt high-pressure sodium bulbs. Those were the efficient light sources of a few generations ago.

Limit the Depth of Discharge of your lead-acid batteries, to extend their life. Some people say not below 50%, but I disconnect loads at 70% keep inverter running to 80%. By vendor graphs of cycle life vs. depth of discharge, you can see where total watt-hours of useful cycle life decreases more sharply, and choose how quickly you want to wear them out.

Light sensor plus timer, and/or motion sensor, could reduce power consumption.

The full data sheet for a PV panel will include "Temperature coefficient of Voc (open-circuit voltage)", and can be used to determine how much higher voltage will get at 8C. I look up historical records and use that temperature. You do not want to exceed SCC voltage specs.
 
I have yard lights with 70 watt high-pressure sodium bulbs. Those were the efficient light sources of a few generations ago.

Limit the Depth of Discharge of your lead-acid batteries, to extend their life. Some people say not below 50%, but I disconnect loads at 70% keep inverter running to 80%. By vendor graphs of cycle life vs. depth of discharge, you can see where total watt-hours of useful cycle life decreases more sharply, and choose how quickly you want to wear them out.

Light sensor plus timer, and/or motion sensor, could reduce power consumption.

The full data sheet for a PV panel will include "Temperature coefficient of Voc (open-circuit voltage)", and can be used to determine how much higher voltage will get at 8C. I look up historical records and use that temperature. You do not want to exceed SCC voltage specs.

Thanks a lot for the information, I'll see what type of solar panels i can get and also check on battery availability, i have made base info on my project and i hope i don't end up burning or blowing anything up once done.
 
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