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HighDesert · 09-19-2019, 11:52 AM

I am considering adding rooftop solar to my motorhome in the coming year. My first question is the difference, other than price, of Zamp vs Renogy panels - is one better than the other? Online info all seem to list Renogy, but rarely mention Zamp. Then the question of how many, or how large of a panel(s) would I need? I have a 2019 Tiffin 32SA, with 4, 6 volt batteries, PSW inverter, and a domestic refrigerator. My main quest is to be able to keep the batteries charged enough that I do not have to run the onboard generator 4 - 6 hours a day to keep batteries charged, so refrigerator stays cold. Ultimately, I would like to upgrade to AGM batteries, once these expire. Would appreciate any input.

twinboat · 09-19-2019, 01:01 PM

Panel watts are panel watts. I don't see how brand name can change that.

If you have the room, go with 600 watts, 400 minimum. That should cover the fridge use and send some charge into the battery bank.

As far as AGM batteries, the only benefit of them, in your situation, will be not having to check the water once a month.

They claim faster re-charge but you need a bigger charger. That's not solar.

As far as capacity, many AGMs have a bit less then there flooded counterparts. They also have comparable deep cycle life.

Cougarkid · 09-19-2019, 05:53 PM

Be sure to get a good, quality, charge controller for your system. Also, a good battery monitor will help you keep track of your batteries.

justinpirie · 09-20-2019, 09:56 AM

The big advantage with AGM over FLA is higher depth of discharge though. As twinboat says, panels are panels. I really like Victron for monitoring and charge controllers.

Cougarkid · 09-20-2019, 11:25 AM

Read ALL of this stuff.

https://handybobsolar.wordpress.com/

People will say he is outdated, but it will teach you a lot about solar. He updates periodically.

I used this information to build the solar setup on out 42' RV. 5000watts of panels (2-150 and 1-200), Tristar 45amp charge controller, Trimetric RV-2012 Battery Monitor, 600amp GE fused disconnect, 500amp shunt., 4 Autocraft 6V G2 216AH batteries. Using a Xantrex 2012 2000watt inverter/charger w/ remote. Added in a 300watt PSW inverter for my computer.

We are NOT running a "house" refrigerator.

If you install a good battery monitor first, you can easily determine what your power needs are. You can use a power estimator (on-line) to figure your power needs, also.

twinboat · 09-20-2019, 12:13 PM

Quote:

Originally Posted by justinpirie

The big advantage with AGM over FLA is higher depth of discharge though. As twinboat says, panels are panels. I really like Victron for monitoring and charge controllers.

If you do some research, you will find that " Depth of discharge " cycle life between AGM and flooded batteries is almost the same.

Discharge both chemistries down to 80% DOD and you cut the cycles in half of a 50% DOD.

justinpirie · 09-20-2019, 03:11 PM

Quote:

Originally Posted by twinboat

If you do some research, you will find that " Depth of discharge " cycle life between AGM and flooded batteries is almost the same.

Discharge both chemistries down to 80% DOD and you cut the cycles in half of a 50% DOD.

Really? I’d thought this was the case:

“The leading advantages of AGM are a charge that is up to five times faster than the flooded version, and the ability to deep cycle. AGM offers a depth-of-discharge of 80 percent; the flooded, on the other hand, is specified at 50 percent DoD to attain the same cycle life. The negatives are slightly lower specific energy and higher manufacturing costs than the flooded, but cheaper than the gel battery.”

https://batteryuniversity.com/learn/..._glass_mat_agm