Thread: Permanent roof mounted solar panels

Hi Flagg and with 4 x 40w solar panels, fitted in a flat set up, you will get about 4 amps per hour, average over an 8 hours.

So say about 30Ah produced.

As for your fridge, a rough guesstimate would be about 25Ah in a worst case situation.

Next, and while the USI-160 has a MUCH lower power consumption compared to other isolators, you will still need to factor in the USI-160’s power consumption.

When in SHARED Mode, it will draw just under 200ma, so you will need to factor in another 5Ah needed.

Your inverters will probably draw very little because of the time frame needed to recharge the different devices, but this is something you will need to workout, based on your specific usage.

With what you are planning to do, you should get close to or even more than required power from your 4 solar panels.

The best trick is to do a driveway test.

Set everything up in your back yard and just see if the system meets your needs.

One other point, as posted above and depending on your intended usage, a bigger alternator is a good suggestion particularly as you are using ultra fast charging Optima batteries.

There is nothing that will charge these batteries faster than a good sized alternator.

Hi again Flagg and yes the USI-160 will allow both solar and alternator charging at the same time.

Also, if you set the USI-160 to SHARED Mode, you can connect the solar power anywhere in the set up, EG to the cranking battery or auxiliary batteries, or even to a rear mounted Anderson plug, if you fit one, and all batteries will be charged by the solar panels.

If for some specific reason you only want the auxiliary batteries to be charged by the solar panels, set the USI-160 to IGNITION Mode and connect the solar panels to the auxiliary batteries, and then only the auxiliary batteries will be charged.

your 75 amp alternator is fine for recharging those optimas and you will get anything up to 50 amps of charge from that alternator while you are at cruising speeds.