Boondock with SolarFlex 200 + Portable Panel

[LG123]

I'm close to pulling the trigger on a new Springdale 251BH, which comes with Solar Flex 200 (200 watts of solar and 15pm controller).

I already own a Renogy 100 watt panel and 30amp charge controller that I use at home for power outages.

Will it be a problem to attach this extra panel and controller directly to the batteries on the trailer to help keep them charged while we're boondocking?

Or will I need to plus into the Zamp charge port instead (and reconfigure it to work with a Renogy panel)?

And if I'm using the Zamp charge port, will I need to upgrade the existing charge controller anyway since a 15amp controller can't handle much more than 200 watts of solar panels?

[LG123]

For some extra context, I'll also be adding a 1000W inverter so the outlets will work to charge devices and power a cell signal booster. Other than that, we'll only be running the fridge, water pump, and a few lights.

[JRTJH]

I would NOT connect two charge controllers from two separate solar systems to the same battery at the same time. Doing so could spell disaster for battery charging.... To me, that's sort of like running on shore power and the generator at the same time... Could be 120 or could be 240 volts on your 110 outlets... or could burn up the generator or burn up the campground circuit breaker panel from backfeeding. It's the same with DC power from a solar system, just not as deadly to the people exposed, but with damaging consequences for the equipment.

That said, why not use the "existing charge controller installed by Keystone, add your portable solar panel to the input mix and keep the portable charge controller as a "spare" ???

[LG123]

Originally Posted by JRTJH

That said, why not use the "existing charge controller installed by Keystone, add your portable solar panel to the input mix and keep the portable charge controller as a "spare" ???

Your guidance makes good sense. My issue with the existing charge controller is that a 15amp controller would be overloaded at 300 watts of solar so I'm concerned I'd fry it if I'm using the charge controller plug in addition to what's already on the roof.

But the stock charge controller is higher quality than the one I own and provides some nice benefits like bluetooth monitoring so it would be nice to keep it

[peanut]

I would consider replacing your current solar charge controller with a larger, mppt one.

https://www.amazon.com/SmartSolar-MP.../dp/B073ZJ3L13

Then you could do what JRTJH suggests with no worries. More efficient and larger capacity. Future proof your rig with the option of adding another 100 watts of solar in the future if wanted/needed with hardly any additional work needed.
Just my thoughts.

[LG123]

Originally Posted by peanut

I would consider replacing your current solar charge controller with a larger, mppt one.

https://www.amazon.com/SmartSolar-MP.../dp/B073ZJ3L13

Then you could do what JRTJH suggests with no worries. More efficient and larger capacity. Future proof your rig with the option of adding another 100 watts of solar in the future if wanted/needed with hardly any additional work needed.
Just my thoughts.

This is true, it's really not much work or expense to upgrade the charge controller and it would make everything simpler. Thanks

[LG123]

Originally Posted by JRTJH

I would NOT connect two charge controllers from two separate solar systems to the same battery at the same time. Doing so could spell disaster for battery charging.... To me, that's sort of like running on shore power and the generator at the same time... Could be 120 or could be 240 volts on your 110 outlets... or could burn up the generator or burn up the campground circuit breaker panel from backfeeding. It's the same with DC power from a solar system, just not as deadly to the people exposed, but with damaging consequences for the equipment.

That said, why not use the "existing charge controller installed by Keystone, add your portable solar panel to the input mix and keep the portable charge controller as a "spare" ???

Here’s the response I got from the dealer. So far everything else he’s told me has checked out so I’m inclined to trust this:

“There would not be a conflict between the roof mounted and side mounted solar inputs as they are not wired together. As they are not wired together, there would be no concern about panel compatibility, as each charge controller would be charging the battery independently.”

[NH_Bulldog]

I think the concern that was mentioned is that you have one solar package with its charge controller providing power to the batteries. Then you add a second solar package with its own charge controller providing power to those same batteries. Two separate systems charging the same batteries doesn’t sound like a good idea to me, especially if one of the charge controllers is an inexpensive model.

Think of it like plugging your RV into shore power and letting the converter charge the batteries, while at the same time you connect a standalone battery charger to the batteries. Do you trust with absolute certainty that they are going to play nice together without burning up something expensive?

I would absolutely NOT take the word of the RV dealer without solid facts and knowing that their qualifications regarding solar is far beyond what they read in the sales brochure.

Ultimately they could be right, but it is worth doing your homework on.

[jxnbbl]

I don't understand the impact on the battery. The batteries are always being charged from 2+ sources most of the time.


1. When you are on shore power you end up with the roof solar + the converter doing their things independently.
2. When you are driving you have the roof solar + the TV alternator charging.


What I think is most important is that the solar panels be within spec of the controller and if you use a portable solar panel it just isnt' added into the source array to the existing controller and has its own.


Now having said all of this I have NOT experienced this hook up although I was thinking about it for situations where the trailer is totally shaded and you could move a portable panel into the sun.

[LG123]

Originally Posted by jxnbbl

I don't understand the impact on the battery. The batteries are always being charged from 2+ sources most of the time.


1. When you are on shore power you end up with the roof solar + the converter doing their things independently.
2. When you are driving you have the roof solar + the TV alternator charging.


What I think is most important is that the solar panels be within spec of the controller and if you use a portable solar panel it just isnt' added into the source array to the existing controller and has its own.


Now having said all of this I have NOT experienced this hook up although I was thinking about it for situations where the trailer is totally shaded and you could move a portable panel into the sun.

Getting around the shade issue is part of the reason this setup is appealing. Thanks for the input on there commonly being two sources of charge for the battery at any point.

[SR71 Jet Mech]

I have 3 separate arrays. A 500w on one side of my roof, a 600w on the other side of my roof and a 600w “portable “ ground setup. Each on it’s own Victron mppt charge controller. I can run one or all at the same time. 600ah of LifePo4.
Also a Victron battery sense. All talk to each other via Bluetooth.
Most Mppt chargers will only accept and throttle the amount of incoming voltage as to only allow the output max current of the charger. As long as you do not exceed the max incoming voltage of the controller. Mine will shut one, two or all three chargers down on its own and come on when needed depending on load.

That being said, have not worked with PWM charge controllers. I would make sure you size as close as possible your array and controller and if using multiple arrays, get “like” controllers that will talk to each other. Still, they should sense the battery levels and adjust accordingly from bulk to absorption to float to off depending on battery chemistry.

Just my $.02

Scott

[Gord]

Originally Posted by LG123

I'm close to pulling the trigger on a new Springdale 251BH, which comes with Solar Flex 200 (200 watts of solar and 15pm controller).

I already own a Renogy 100 watt panel and 30amp charge controller that I use at home for power outages.

Will it be a problem to attach this extra panel and controller directly to the batteries on the trailer to help keep them charged while we're boondocking?

Or will I need to plus into the Zamp charge port instead (and reconfigure it to work with a Renogy panel)?

And if I'm using the Zamp charge port, will I need to upgrade the existing charge controller anyway since a 15amp controller can't handle much more than 200 watts of solar panels?

You could upgrade your trailer charge controller to say a 40 amp MPPT unit and install the solar panel paralleling jacks (Renogy). The trailer panels would always be connected and your portable unit (panels only) could be plugged in as needed.