GlowInTheDark
New Member
- Joined
- Oct 15, 2021
- Messages
- 6
Hi,
I’m planning a portable power system as my first solar/off-grid project and I’d appreciate any veteran input to show me my mistakes before I buy them
I’m hoping to start buying components in the next two days, so if anyone can give quick feedback I would be very grateful.
Components are all relatively lightweight because the system needs to be easily relocatable.
Numbered items on the circuit diagram:
b. 2000W maximum continuous load required (spikes to 2500W)
b. 25.6V Nominal Voltage
c. 1280 WH of Energy
d. 100A Max Continuous Discharge Current
e. 100A Max Continuous Charge Current
f. Cycle Life 3500 (80% DOD)
g. ≤80mΩ Internal Impedance
h. 29.2V Charge Voltage
i. 20.0V Discharge Cut-off Voltage
j. Charge Temperature = 0°C to 60 °C
k. Discharge Temperature = 20°C to 60 °C
l. https://roarpower.nz/off-grid-solar-products-nz.html#battery2450
b. 3000VA / 2400W Continuous output power at 25°C
c. Charger
b. Will prop these up using collapsible tent poles
c. Monocrystalline
d. Rated maximum power (PM): 200W
e. Voltage at Pmax VMP: 18.70V
f. Current at Pmax IMP: 10.86A
g. Open-circuit voltage (VOC): 22.51V
h. Short-circuit current (ISC): 11.53A
i. Tolerance ±3%
j. Normal operating cell temp (NOCT): 47 ±2°C
k. https://www.steeringandsuspensionwa...etech-4x4-200w-foldable-solar-blanket-dtsb200
b. 1700W continuous power output
c. https://www.gtpower.co.nz/shop/Inverter+Generators/GT2100ESi.html
b. 230V
b. If not using the extension cable (item #8), then panels will be 10 meters from the Solar Controller
c. Will want the ability to reconfigure the panel wiring so that they’re all in series (e.g. on cloudy days), so am expecting to have to use MC4 connectors.
b. Only used if panels need to be far from inverter
c. Y-connectors will be used to combine any parallel strings into this one cable
As mentioned - I'm new to all this, so am keen to hear of anything I haven't thought of.
Many thanks in advance!
GlowInTheDark
I’m planning a portable power system as my first solar/off-grid project and I’d appreciate any veteran input to show me my mistakes before I buy them
I’m hoping to start buying components in the next two days, so if anyone can give quick feedback I would be very grateful.
Components are all relatively lightweight because the system needs to be easily relocatable.
Numbered items on the circuit diagram:
1. Household appliances
a. 3.5KWh of 230V AC required dailyb. 2000W maximum continuous load required (spikes to 2500W)
2. Batteries × 4 (specs for each battery is as follows)
a. LiFePO4 24V 50Ah in parallelb. 25.6V Nominal Voltage
c. 1280 WH of Energy
d. 100A Max Continuous Discharge Current
e. 100A Max Continuous Charge Current
f. Cycle Life 3500 (80% DOD)
g. ≤80mΩ Internal Impedance
h. 29.2V Charge Voltage
i. 20.0V Discharge Cut-off Voltage
j. Charge Temperature = 0°C to 60 °C
k. Discharge Temperature = 20°C to 60 °C
l. https://roarpower.nz/off-grid-solar-products-nz.html#battery2450
3. Inverter/charger/solar controller
a. Victron EasySolar 24V/3000VA/70-50 MPPT150/70b. 3000VA / 2400W Continuous output power at 25°C
c. Charger
i. 28.8V Charge voltage 'absorption'
ii. 27.6V Charge voltage 'float'
iii. 26.4V Storage mode
d. MPPTi. 70A Maximum output current
ii. 2000W Maximum PV power
iii. 150V Maximum PV open circuit voltage
e. https://www.victronenergy.com/upload/documents/Datasheet-EasySolar-with-Color-Control-EN.pdf4. PV panels
a. Model = DTSB200 (Solar blankets - fold up to briefcase size)b. Will prop these up using collapsible tent poles
c. Monocrystalline
d. Rated maximum power (PM): 200W
e. Voltage at Pmax VMP: 18.70V
f. Current at Pmax IMP: 10.86A
g. Open-circuit voltage (VOC): 22.51V
h. Short-circuit current (ISC): 11.53A
i. Tolerance ±3%
j. Normal operating cell temp (NOCT): 47 ±2°C
k. https://www.steeringandsuspensionwa...etech-4x4-200w-foldable-solar-blanket-dtsb200
5. Generator (backup for cloudy days)
a. GT2100ESib. 1700W continuous power output
c. https://www.gtpower.co.nz/shop/Inverter+Generators/GT2100ESi.html
6. National electrical grid
a. If it’s availableb. 230V
7. Wiring for PV panels
a. 4mm² (12 AWG)b. If not using the extension cable (item #8), then panels will be 10 meters from the Solar Controller
c. Will want the ability to reconfigure the panel wiring so that they’re all in series (e.g. on cloudy days), so am expecting to have to use MC4 connectors.
8. 10m extension cable
a. 6mm² (10 AWG)b. Only used if panels need to be far from inverter
c. Y-connectors will be used to combine any parallel strings into this one cable
As mentioned - I'm new to all this, so am keen to hear of anything I haven't thought of.
Some questions that come to mind:
- What happens when my battery is full and the panels are still in the sun? Where does the electricity from the panels go? Does it put strain on any part of the system?
- I want to ensure the batteries’ State of Charge (SOC) remains synchronised, so I expect to need one or more battery balancer. How many should I use, and where should they be wired? I can’t find an example online for wiring battery balancers into a bank of parallel batteries. https://www.victronenergy.com/batteries/battery-balancer (I've heard a "shunt" may be helpful in this circuit but I haven't had time to learn what that is yet)
- Is the impedance of these batteries normal? Other similar batteries have an impedance of ≤20mΩ
Many thanks in advance!
GlowInTheDark