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DC relays for solar panels

DC to DC relay  DC power relay
250VDC    25 amp                        400VDC  200 amp

These are the big boys
Connect big volts and amps to the contacts
Operate the coil using 12-24 Volt DC
DC to DC relay/ mechanical type
240 Volt DC power relay /26 amp to 200 amp DC

Full on-off contacts/ 12 or 24 volt DC coil
250 volt / 25 amp DC load
250V x 25 amp = 6250 watt
Connect 12 or 24 volt DC to terminals 3-4;
Connect load to terminals 1-2

Electromechanical DC-DC G9EB-1 relay
24 VDC coil and 400 VDC/ 200 amp contacts
Omron relay at online

Omron DC-DC pdf
DC power relay spec sheet
Convert AC water heater to DC water heater
Dave says
Normal power relays burn up when they are fed DC power instead of the AC power they are rated at.   Relays can be delicate.:
I had an issue with relays in my controller box getting destroyed when I switched elements between 240VAC and 120VAC. I solved the issue by turning off the power relay (DPST relay) feeding the 120/240 selection relay (SPDT relay), then flipping 120/240 relay state, then turning the power relay back on.   I figured the arc flash between the N and Hot side of the DPST relay was being aided and abetted by the armature moving between contacts while under power.

Blowout relay
Magnetic blowout relay
DC relay
90 mm tall x 50 mm wide/ 25.4 mm per inch
3.5" tall x 1" wide
Electric vehicle motor controller/ DC contactor
Electric vehicle DC relay
Normally closed (normally ON ... must activate to turn OFF)
Contacts With blowouts 96 volt max 250 Amp
48 volt max 250 amp
Rated 1 million cycles

AFS series
C110B series
Specification sheet/ pdf
Electric vehicle motor controller
Load contacts: 96 volts DC 200 amp DC
96 volts @ 250 amp
28 volt 30 amp dc relay Load Contacts: 28 volt DC 30 amp DC
9A series W9AS1D52-110/ 30 amp @ 28 volt DC
W9AS5D52-110/ 30 amp @ 28 volt DC
Magnecraft power relays
Schneider power relays
28 Volt 50 amp DC relay
Coil 12-24 VDC
Load contacts 26 VDC  40-50 Amp
12 Volt DC coil/ power relay
Load Contacts: 28 VDC 40-50 amp DC

24 volt DC coil/ 40 amp @ 26 VDC
12 volt DC coil/ 40 amp @ 26 VDC
6 volt DC coil/ 40 amp @ 26 VDC
110 volt DC coil/ 40 amp @ 26 VDC
W199AX-3 relay
W199PX-13/ 50 amp at 26 VDC = 1400 watt
X199 Magnecraft relay
Magnecraft W199 DC relay

Magnecraft relay / pdf
relay cover Box and cover for heavy-duty Magnecraft relay
Magnecraft relay with NO NC terminals 120 volt coil or 24 volt coil

Buy from my affiliate links
Magnecraft 50-1289-1 relay box and cover

How to reverse motor with switch
Difference between contactor and relay
Relays for DC motors and solar panels
Control motor with 2 switches
Start two motors at different times
200 amp DC relay DC relay/ automotive / Input voltage 12 Volt DC
Contacts: 12 Volt DC /  200 amp DC

4 gauge wire
12 volt 200 amp relay at Amazon
200 amp DC relay
More high amp 12 Volt DC relays
24 Volt DC coil
Contacts 90 amp AC/ 3-pole + 1NO/1NC
Dayton 6ECD9 at Amazon
DC relay DC relay/ Input 3-28 Volt DC
Contacts: 120 Volt AC / 26 amp
3-32 volt DC input/ control 120 Volt 25 amp AC
Opto relays at Amazon

Solid state relay data sheet
Solid state relay DC relay data sheet
3-phase solid state relay DC relay/ Input 3-32 VDC
Contacts 3-phase 25A AC 480 volt

3-phase solid state relay at Amazon
DCP200 relay DC200P 5-200 VDC solid state relay
Contacts: 24 VDC 1 amp DC

DC200P 200 volt DC at Amazon
Opto relays at Amazon

Solid state relay data sheet
Solid state relay DC relay data sheet
DC60MP solid state DC relay DC60MP 5-60 VDC solid state relay
Contacts: 24 VDC 3 amp DC

DC60MP 60 volt DC at Amazon
Opto relays at Amazon

Solid state relay data sheet
Solid state relay DC relay data sheet
DC to DC solid state relays
Buy from my associate links
100 volt 25 amp DC Relay
200 volt 25 amp DC relay at Amazon

Relay safety cover
Heat sink

Convert water heater from AC to DC
Electromechanical relay vrs solid state relay/ pdf
Switching function solid state relay/ pdf
DC contactor 3-pole contactor wired for DC loads
DC direct current is different than AC alternating current.

AC current is a wave that crosses zero volts each time generator rotates 50-60 times per second,. US 60 cycles. Europe Asia 50 cycles.
DC current is a straight line. The voltage does not oscillate or vary like AC. Electrons flow through circuit at same voltage at all times.

When high voltage AC is turned off, the voltage drops to zero frequently.
When AC voltage hits zero, then the arc or spark or heat is easy to extinguish.
Result: AC switchgear like contactors last million repetitions without melting the points
High voltage DC is different. When high voltage DC is turned off, the electrons keep pushing. Voltage never reaches zero.
Result: DC voltage causes arc or spark or heat that is difficult to stop. Basically the electrons keep piling into the contactor.
DC switchgear must be rated for DC voltages, and be capable of extinguishing DC arc.
Illustration shows one method of extinguishing DC arc using 3-pole contactor. The circuit has 3 parallel switches on the positive wire.
With a 4-pole contactor, 3 poles can be used to turn off Positive, and 1 pole to turn off Negative
Add resistor in parallel with inductive winding* helps eliminate arcs. *Inductive winding is motor load

3-pole contactors at Amazon
CN101A timer wiring
Larger image/ amico timer with dust cover

dust cover for amico timer
Dust cover
CN101 timer/ 12 VDC input
Contacts: 12 VDC 16 amp DC

7 day 17 on-off settings
12-24 Volt DC programmable timer

Buy from my associate links:
Amico 120 volt 7-day timer
12 Volt/ 16 amp/ DC timer at Amazon
CN101 12VDC timer at Amazon
24 Volt/ 16 amp/  DC timer at Amazon
Dust cover for Amico timers at Amazon
Amico timers at Amazon
Transformer: 120-240 Volt to selectable DC voltage

CN101A/ amico timer manual/ pdf with wiring
How to wire amico timer
30 amp DC safety switch 30-60 amp DC safety switches/ fusable
Heavy Duty 250 V Dc Voltage; 30 Ampere
Square D 30 amp DC HU361RB
Square D 60 amp DC H222AWK

DC safety switches
Generic: How to wire safety switch
Convert AC water heater to DC water heater
DC relays for solar power
ST3PF off delay timer 12 VDC/ 0-3 minute delay timer
Contact rating: 12 VDC 3 amp DC

12 volt DC relay
12 volt dc relays at Amazon
Photovoltaic water heater
Connect DC directly to water heater
Photovoltaic water heater
Electric Solar panel connected to electric water heater

If solar panels deliver enough Kw, then the water heater thermostats will melt
AC rated elements will work with DC.
Ordinary water heater elements will work with DC power
Ordinary water heater thermostats will melt with DC power
Buy from my associate links:
Elements at Amazon
DC Element at Amazon

Quote: "a photovoltaic water heating (PVWH) system requires neither a battery for energy storage nor an inverter to convert the DC power supplied by the photovoltaic array into an alternating current (AC) power. The DC power supplied by the photovoltaic array is fed to one or more resistive elements that are immersed in a water storage tank."
How to convert AC water heater to DC
DC solar water heater

Is it worth replacing $100-200 contactor or relay each year or two just to make a direct DC water heater vrs converting DC to AC as is typical? Cost analysis not known.

Dave says:
Omron is cheap relative to the the cost of the solar modules.     I think PV direct water heater is still in the game

How to convert AC water heater to DC
Omron DC-DC relay shown at top of page is best.
3-pole 90 amp AC with 120 volt coil is next best.

The 48 volt DC 100 amp selling for $100 on Amazon... is same-similar to golf cart DC solenoid and same price.
Maybe it will work for diagram on left but not full-blown DC water heater

Called golf cart guy:
Golf cart guy said his 48 volt solenoid will burn out with 96 volts or more.

Golf cart guy says they replace DC solenoids each 5 years on golf cart...each round of golf you turn cart on-off 40-50 times... you play golf 40 times per year ... so we might estimate a DC relay is good for 2000-4000 activations.

Can we get same service from 3 pole AC contactor? NO?
Can we get same service from Omron DC-DC relay? Spec sheet says Yes

Called auto salvage yard... no such animal as DC solenoid unless yard has hybrid or electric car ... very little demand for electric or hybrid car parts...  because repairs are done at dealer.... dealer orders parts from original builder of car who got parts special made for that car.
No parts left, no repair.
Dealer DC parts would be costly.

The others relays-contactors are too small for direct DC solar water heater

Called DC contactor manufacturer:
Salesman very knowledgeable ...
They do not sell very many DC contactors... and he laughed .... indicating the demand must be miserable... and he didn't have a price.
They do not stock them. They manufacture those contactors to order.
They stock the UPS contactor... same rating as golf cart solenoid.
Too small for full blown DC water heater

Manufacturer's can make a DC contactor to exact specification.... salesman can put together a quote for 100 pieces.

If a big company can find profit making DC solar water heater... then the relay will be manufactured,
... and parts available off-the-shelf?
Outlook seemed unlikely among folks I spoke with.
But history never travels straight line... DC water heater invention is viable if Omron is available and works reliably.


Test for breaks in wire/ Test for voltage
Most appliance require 80% rated voltage to function correctly
Multimeters at Amazon
Electric testers at Amazon
How to test and replace element
How to test thermocouple
Element tests for 120 volts
How to test wire
Safety when testing wires:
Never touch wet or previously flooded appliance.
Never stand on wet surface when working on electric.
Never stand on bare soil, put down dry boards.
Tape tester leads to wood sticks to keep hands away from power.
Use non-contact voltage tester before touching wires.
Never touch or lean into any made of metal.
Remove metal objects from pockets.
Do not use oxygen or fuel accelerants in same room as electrical repairs

Basic house wiring

Non-contact voltage tester

Test for power without touching connectors
NEVER assume power is OFF

Non-contact voltage tester Amazon
Electric testers at Amazon 
How to test electric power is off
wire connector assortment

Twist-on wire connector assortments

Do not reuse old connectors 

Connector assortment at Amazon
Connector assortment at Amazon

How to select and install twist-on wire connectors
Weatherproof wire connector

Weatherproof wire connector

Connector cavity is full of silicone
Built-in cover keeps silicone in place
Protect from water, dust etc
Buy from my affiliate links
Weatherproof size 14 to 6 Amazon
Weatherproof size 22 to 8 Amazon

How to select and install twist-on wire connectors
Wire connector wrench

Wrench to apply wire connectors

Tighten connector 

Wire connector blaster
Twist connector wrenches at Amazon

How to twist wire
How to select and install twist-on wire connectors

How to install terminals


Terminal kit
Blue for 16-14 wire
Yellow for 12-10 wire
Read about terminals
Push on wire connectors

Push-on wire connectors in place of twist-on connectors

Push on wire connectors Amazon
Red 3P connector for 10-14 gauge wire
Lever connectors for stranded wire at Amazon

linesman pliers
Buy tools:
Wire strippers at Amazon
Linesman pliers
Utility knife at Amazon
End cutting nippers at Amazon

Fire inside timer caused by stranded wire
Keep enclosure door closed at all times

Fire caused by stranded wire

Do not use stranded wire under screw plate

Applies to timers, switches, outlets, pumps etc.
Small devices, with small loads, such as lamp socket, stranded wire is fine
Add solder to 1" length of tightly twisted stranded wire to make into solid wire
Heat wire. Touch solder to wire. Let cool. File away over-solder.
soldering guns

Timer caught fire
Orange 10 gauge 30 amp

Orange/ #10 gauge for for 30 amp circuits including water heater
with ground
10-2 gauge/ 30 amp
10-3/ 30 amp

NMB is house wiring
UF is underground

Yellow 12 gauge 20 amp

Yellow/ #12 gauge wire for 20 amp
with ground
12-2 gauge/ 20 amp
12-3/ 20 amp

Rolls of stranded wire

NMB is house wiring
UF is underground
White 14 gauge 15 amp

White/ #14 gauge wire for 15 amp
with ground
14-2 gauge/ 15 amp
14-3/ 15 amp

NMB is house wiring
UF is underground

Copper ground wire
Use same size as other wire in circuit

Spools of ground wire
Ground rods at Amazon
Gas and electric water heaters Buy:
Industrial electric at Amazon

Industrial supplies at Amazon

Industrial and scientific Amazon
Intermatic control centers Intermatic control centers:
+ manuals and parts

Including Z-wave
box timers Compare box timers

Control with Z-wave
programmable timer Compare programmable timers

Control water heater with programmable wall timer
Countdown timers Compare countdown timers

Control water heater with countdown timer

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