How many solar watts required?

Picked up my new Elkridge 38MB last week. Noticed it has a solar connect. I need to double check to be sure but I doubt there is an integrated MPPT controller meaning I will need that in addition to a Solar panel. So my question regarding the number of watts/panels is with regard to charging the battery to be able to run my residential fridge for longer periods of time. I know I have a 1000 watt inverter and 1 12v battery. Yes I have room for another battery at some point. I keep my RV plugged in while we are away but wanting to up my downtime if we were to lose power...So I am looking at adding a panel or so to make that happen. If I had a single 100w, I am guessing that would be at most 8 amps at 12v...but that is really where my question is in trying to keep the battery charged up in daylight hours so it can make the night til the next day.

Any ideas on what that would take?

--Mickey A
(guess I need a sig here)

If the Solar Panel option is available and ordered, I understand Heartland is using a 300 watt panel and I think a 30 amp charge controller. You may want to reach out to Heartland Customer Service (877-262-8032) to find out if your factory Solar Prep will work with the Solar Panel / Controller option and if so, maybe get it this optional gear from Heartland.

You'll likely need to add at least one more battery. And to be certain as to your solar/battery needs, you need to learn more about the current draw of your refrigerator over the period of time you want to power it via battery and add some on top of that for even hotter days. Then size your battery bank and solar panel / charge controller based on details of your need.

The Landmark factory solar option may use heavier gauge wire than the pre-wiring on your Elkridge as the Landmark option is designed to support up to two 300 watt panels (600 watt total). There are also other components in the Landmark that are matched to the panel, wiring and controller. The Elkridge is probably set up for a minimal solar installation.

On the Landmark, when the 300 watt solar option is ordered, Heartland recommends adding 2 batteries (4 total). The solar array charges the batteries. The batteries supply power to the inverter and supported appliances/outlets.

You probably would do best to start with a 2nd battery. I'd think you would want two group 27 batteries at a minimum; larger is possible. That'll significantly extend the refrigerator runtime. Then, whatever you add in the way of solar wattage will help keep those batteries charged up, further extending refrigerator runtime.

So just to follow up and complete this thread for those that are "listening" - I called Heartland - they sort of told me what I have already forgotten about. Look up Go Power Solar kits. You can size basically for how fast/many batteries that you have. Since I "currently" have 1 battery, I wouldn't need to over populate myself with panels. Since these kits are expandable, I can also add panels as necessary.

I do agree, that I really do need to start by adding an additional battery first - normally would be easy other than I need to go procure a ventilating battery case to get the gasses out of that small compartment. Noting that they really could have designed the existing one better by have easy access clips rather than screwing the top and bottom together. As important as monitoring battery levels, you would think they would make that easier.

Off to do my research...

--Mickey A

The first step in this process is to really figure out how much power you need/use. I installed a Victron BMV-712 (linked below to Amazon) that monitors all my battery usages....both outgoing and incoming power. Get the version with Bluetooth, so you can see all info on phone/tablet.


One you have the Victron installed, go dry camping for a weekend in a park WITH power, but don't connect when you arrive. Then using the Victron unit see how much power you pull over those days. Then let us know.. If you drain your batteries faster than you thought (which I'm sure you will) then you simply plug in and continue to enjoy your trip.

NOTE - Remember you can only use 50% of your amp hours for any battery other than Lithium. That means, once you hit 12v (and lower) your are already at 50% and are now damaging the batteries and their ability to return to 100% SOC.


We can then calculate the panels you'll need and provide you with recommendations on controllers and wiring.


The final step will be batteries. You could have 3000 watts of solar panels and still have problems, as the biggest problem is battery capacity. If your batteries are not capable of holding enough power, then you'll always have issues, regardless of how much solar you have.


https://amzn.to/2tfm1Qv