Solar question

[AidenJ]

I currently have a 85 watt panel on camper roof, the controller is buried under the counter. Purchased as a kit and now not sure size of controller. It does a fair job of charging our 2 group 29 flooded batteries. I am looking at the folded solar panels with their own controllers to add to system. So my question is can I use both with their own respective controllers?

[Vintage465]

It really comes down to a couple things: How much you want to set up when you get on site.....and how much you want to take down when you leave. The other thing is what you want, or can do with out. We don't have a single 120v appliance or 120v need. We are able to accomplish everthing in our trailer that we do at home, it's just that we use 12v and propane......or a campfire. So my 4-6v batteries and 450w of well thought out solar, fixed to the roof, cares for all our needs and I have no suitcase panels to pick up and store when I leave. Cool thing is everone can have their own set up taylored to their needs and be happy with it.

[steveh27]

I've been using a 120 watt portable panel for years. It works great. I bought another 60 watt panel to use beside it.

[AidenJ]

Microlite Mike wrote:

AidenJ wrote:
Thanks, I was afraid they would buck each other

No such happening. No different than having shore power plugged in with converter charging batteries and solar panel putting power into the battery.

The battery will suck up as much power as it needs and both charging devices will provide power as long as the battery is accepting it. When battery is "full" it's voltage will rise and shut charging devices down to float voltage. One may switch to it's float output sooner than the other due to slight differences in how they read the voltage but when the battery is "hungry" both will peacefully coexist and feed the battery.

Thanks for helping me understand. I've been holding off making any purchase.

[Microlite_Mike]

AidenJ wrote:
Thanks, I was afraid they would buck each other

No such happening. No different than having shore power plugged in with converter charging batteries and solar panel putting power into the battery.

The battery will suck up as much power as it needs and both charging devices will provide power as long as the battery is accepting it. When battery is "full" it's voltage will rise and shut charging devices down to float voltage. One may switch to it's float output sooner than the other due to slight differences in how they read the voltage but when the battery is "hungry" both will peacefully coexist and feed the battery.

[AidenJ]

I did think about just replacing the roof mounted panel with a larger new one, but the existing panel is still producing and I hate to just trash it. It still buys me 1 extra day without using a generator. Thanks for all the input.

[AidenJ]

Lwiddis wrote:
At 85 solar watts there is no wonder that you are having marginal battery recharging. General rule is one watt per wet battery amp hour. While you can do as you propose, you’d be better off to use matching panels of a larger capacity and one MPPT controller. Remember folding solar panels need to be setup every morning and taken down every evening or they grow legs. Roof mounted panels are usually working before you come outside in the morning.

My roof mounted 85 watt does exactly what it was intended to do. Just changing the way I camp. When it finally dies I will do as you suggest. Until then just looking to extend my stays. Where I stay it is highly unlikely that anything would walk.:)

[SJ-Chris]

If you have space to store them, another good solution is to buy USED solar panels for 50-80% less than the cost of new panels. Then, buy some wiring, a fuse, and a solar controller and you have a very inexpensive portable solar setup. If it ends up growing legs and walking off (stolen), you won't be out much (especially if you can keep your charge controller somewhere safe/secure).

I have purchased 250w working panels for as low as $35 each. Check your local craigslist, facebook marketplace, etc. Test the panels before you buy, but there are no moving parts and they should last a long time (20yrs+).

And to answer your question, yes, you should be able to hook up separately from your existing solar.

Good luck!
Chris

[Lwiddis]

Under the counter is a terrible place for a controller. It should be as close to the batteries as possible but not in the same compartment with wet batteries. With AGMs or Lithium they can be such.

[Lwiddis]

At 85 solar watts there is no wonder that you are having marginal battery recharging. General rule is one watt per wet battery amp hour. While you can do as you propose, you’d be better off to use matching panels of a larger capacity and one MPPT controller. Remember folding solar panels need to be setup every morning and taken down every evening or they grow legs. Roof mounted panels are usually working before you come outside in the morning.

[AidenJ]

Thanks, I was afraid they would buck each other

[RLS7201]

YES........

Richard