Adding solar to a 120v battery bank

[hardworkinghippy]

I'm trying to work out a way of doing this without having to connect solar panels in series.

Has anyone ever done it or does anyone have any ideas of how I can do it ?

[adam2]

There is no easy way without connecting a suitable number of PV modules in series.
If you choose modules intended for grid tied use, you wont need that many. You will need modules with a total ON LOAD voltage of about 160/170 volts.
120 volt charge controllers are far less common than 12 or 24 volts, but can be found.

In theory you could charge a 12 volt battery from a single module. Connect an inverter to the battery. Plug a 120 volt battery charger into the inverter.
Most unlikely to be viable in practice owing to the costs, complications, and numerous sources of loss.

Also in theory, DC/DC converters could be used to incease the voltage, but there are a number of potential problems, and in practice I would advise against it.

Please take care with 120 volts, it is potentialy dangerous.
A 120 volt system does have advantages over lower voltages especialy if large loads or long cable runs are involved.
Some appliances will work directly on this voltage thus saving the cost of an inverter and the losses therein.

[An Inspector Calls]

You could add that even a 50 VDC battery is dangerous.

[adam2]

You could add that even a 50 VDC battery is dangerous.

The risks of fatal electric shock is small at 50 volts, it is certainly possible to kill yourself with 50 volts DC but you would have to be very foolish or very unlucky, perhaps foolish AND unlucky.

The other risks are fire from overloaded cables, and fire from electrical arcing.
Any seriously overloaded cable is a fire risk, even at very low voltages. To prevent this correctly rated fuses or circuit breakers are required.
With a single battery of say 12 volts, a main fuse should be fitted as close as possible to one battery terminal.
At higher voltages, it would be better to place the main fuse in one of the series connections.

Electrical arcing at say a loose connection, can produce considerable heat and start a fire.
To prevent this, all connections at 24 volts or more should made within a fire resistant box or enclosure, in line with mains voltage practice.
Continous arcing cant occur with only 12 volts, and SLIGHTLY lower standards might be accepted at this voltage.

Electricity, even at reduced voltages, certainly has its risks, but remember that in general electric lighting is much safer than oil, gas, or candles.

To return to the O/P, 120 volts DC is not much used these days, but can be very useful if significant loads or long cable runs are innvolved.
Unfortunatly it is becoming increasingly hard to find domestic type light switches and socket outlets for 120 volts or more DC.

In the good old days, mains lighting supplies were often at various DC voltages up 240 volts (480 volts for power ) and switches etc were available for such systems.
Most are now marked "AC only" and in practice are fine on DC AT A MUCH REDUCED VOLTAGE. I would be happy to use a "250 volt AC only" light switch on 24 volts DC, and might tolerate it on 50 volts if not heavily loaded.
But for 120 volts DC, either large ugly, industrial switches are needed, or old stock 250 volts AC/DC switches.

I recently had to search hard for 250 volt DC light switches for a nominal 252 volt system, nearly 300 volts on charge .