Solar on Impact 359

[Drazul]

A SolarFlex 200 system can be ugraded to a 400 watt system. But can the 200 watt panels be replced by 300-500 watt panels andm if yes, can two be connected? Figuring this out is really educational, but also . . . . you know.

[NH_Bulldog]

You will have a few technical limitations to consider: the physical size of the panels and the mounting hardware. The presence or lack of presence of a suitable penetration on the roof for the upgraded wiring. The capacity of the existing wiring from the roof and the likelihood that it is insufficient for the higher wattage. You will need to upgrade the solar charge controller from the existing 15A. Increasing solar capacity by that much usually means you will be buying and installing an inverter and shunt.

It’s all doable, but likely will require a good deal of time and expense. I have been shopping for a new 5th wheel and was thinking I might get by with a SolarFlex 200 but when I looked into what it would take to upgrade to a 400 or 600 system myself, I decided to have the factory do it instead. I don’t see where we would be doing any longterm off grid camping, so a 400i system will probably meet my needs for the foreseeable future.

[Drazul]

Thanx. Keystone website states that one can upgrade to two 300 watts panels, but a 30 amp solar controller is necessary. The wiring is 10 gauge so that should be sufficient because the panels are 12 gauge. I’m looking at two Renogy 320 watts 24 volts panels with a Victron 100/50 controller. I have three 100 ah Renogy lithium batteries. If I connect the panels in serial, it will not effect the amps so the existing 30 amp solar port should be sufficient. Since the Impact 359 appears to only power certain outlets with inverted power, and not the a/c, this should be doable, And given that the Impact is 39 feet log, space is not an issue. It think I am correction all this, but can always use advice.

[JRTJH]

If you haven't already, I'd recommend you read the Keystone SolarFlex Quick Start Guide at: https://keystone-rv-dealer-app.cdn.p...DF_QSG_WEB.pdf

On about page 15 is a question: Why can't I build out my SolarFlex 200 to be like the SolarFlex 400i ?

In Keystone's answer to that question you'll find their explanation to some of your limitations. They also provide a recommendation in that paragraph which will take you back to the SolarFlex 200 information page where you'll find an "expand your system" section where you'll find a list of factory recommended "upgrade options".

I'd start there, and then start weighing the "user recommendations" to supplement what the factory provides and their upgrade components.

[Stircrazy]

Originally Posted by Drazul

Thanx. Keystone website states that one can upgrade to two 300 watts panels, but a 30 amp solar controller is necessary. The wiring is 10 gauge so that should be sufficient because the panels are 12 gauge. I’m looking at two Renogy 320 watts 24 volts panels with a Victron 100/50 controller. I have three 100 ah Renogy lithium batteries. If I connect the panels in serial, it will not effect the amps so the existing 30 amp solar port should be sufficient. Since the Impact 359 appears to only power certain outlets with inverted power, and not the a/c, this should be doable, And given that the Impact is 39 feet log, space is not an issue. It think I am correction all this, but can always use advice.

is there any reason you're not looking at the renogy rover MPPT controller, I use the 40amp one in my camper and when I upgrade to larger panels in the 5th wheel, I will go with a renogy controler again.

[NH_Bulldog]

Just a thought; you mention that the current 200w panel has 12-gauge wiring and that the wiring from the roof is 10-gauge? If there is one 10-gauge wire from the roof, you cannot just add another panel and run two panels through that single 10-gauge wire, you will need to add a second 10-gauge wire or upgrade the existing 10-gauge to 8-gauge to accommodate the increased power. Like Stircrazy mentioned, a 40A controller (or larger) would also be needed.

For example;
14 AWG for 15A
12 AWG for 20A
10 AWG for 30A
8 AWG for 40A
6AWG for 55A

As for roof space, that is a question only you can answer. Between roof vents, AC units, attic vents, skylight(s) and tank vents, there may not be as much free space up there as you might think. It may require spreading the panels out across the roof as opposed to locating them in one central area. I would get the panel and mount measurements and cut a carboard template the same size and then head up to the roof and see what your layout might be and whether it is feasible for your situation.

[Drazul]

The solar connector port on the roof that connects to the solar panel controller is 10 gauge wire. However, the wire on the solar panel that connects to the solar connector on the roof (not to the controller) is 12 gauge. From what I gather, so long as the increased amps from adding a second solar panel do not exceed the capacity of the 10 gauge wire (30 amps), there should not be a problem. If the two solar panels are connected in serial, the amps do not increase and the 10 gauge wire should be sufficient. ?????

[ScottA]

Correct, when you wire panels in series you double the voltage but keep the amps the same. Parallel doubles the amps and keeps the voltage the same. Amps are what are important for wire size.


None of the above takes into account the other benefits or pitfalls of doing each - shading, bypass diodes etc.


The renology controller is the toyota vs the victron is the cadillac. (But with toyota reliability


Scott

[Stircrazy]

Originally Posted by NH_Bulldog

Just a thought; you mention that the current 200w panel has 12-gauge wiring and that the wiring from the roof is 10-gauge? If there is one 10-gauge wire from the roof, you cannot just add another panel and run two panels through that single 10-gauge wire, you will need to add a second 10-gauge wire or upgrade the existing 10-gauge to 8-gauge to accommodate the increased power. Like Stircrazy mentioned, a 40A controller (or larger) would also be needed.

For example;
14 AWG for 15A
12 AWG for 20A
10 AWG for 30A
8 AWG for 40A
6AWG for 55A
.

not necessarily, if you run them in series, you will not increase the amperage just the voltage, which is what I would do in his situation. he would still need a new controller that is a MPPT one to do it and to make sure that controler will handle the two panels in series which a renogy 40 amp will as it can handle two 24V panels in series without spending the extra money on the Victron if you don't need to.

[firestation12]

Originally Posted by Stircrazy

not necessarily, if you run them in series, you will not increase the amperage just the voltage, which is what I would do in his situation. he would still need a new controller that is a MPPT one to do it and to make sure that controler will handle the two panels in series which a renogy 40 amp will as it can handle two 24V panels in series without spending the extra money on the Victron if you don't need to.

I agree with stir crazy, putting the panels the OP described (320 watts 24 volts) in series, will easily be within the capabilities of the 10 gauge wire. I would only suggest buying panels with a higher voltage output. Two 37.5 volt panels in series is 8.33 amps. The higher voltage panels begin to output a voltage (suitable for charging your battery bank) sooner in the morning and later before sunset. As long as the solar controller is rated to handle the voltage output of the panels you’ll be ok.

[Stircrazy]

Originally Posted by firestation12

I agree with stir crazy, putting the panels the OP described (320 watts 24 volts) in series, will easily be within the capabilities of the 10 gauge wire. I would only suggest buying panels with a higher voltage output. Two 37.5 volt panels in series is 8.33 amps. The higher voltage panels begin to output a voltage (suitable for charging your battery bank) sooner in the morning and later before sunset. As long as the solar controller is rated to handle the voltage output of the panels you’ll be ok.

solar controllers are usually rated by max input voltage like you said, but you have to use the open circuit voltage (VOC) of the panel, which on a 24V (nominal) panel is usually about 35 to 40V. so the 37.5 Volt panels you are talking about are 24V panels. confusing enough haha

[firestation12]

Originally Posted by Stircrazy

solar controllers are usually rated by max input voltage like you said, but you have to use the open circuit voltage (VOC) of the panel, which on a 24V (nominal) panel is usually about 35 to 40V. so the 37.5 Volt panels you are talking about are 24V panels. confusing enough haha

VOC is what I always refer to when researching panel output. My Renogy 60 solar controller reports the 2 solar panel volts in in series, in that voltage range (70ish). I’ll have to find a pic of my panel data, and see why I missed the 24 volt thing. Thx

[Drazul]

Thank you all for the input. I have it all put together and installed. Planned for future expansion as well. Your comments were appreciated.

[snoobler]

Handy tool for putting panels on a Victron MPPT (don't be surprised if it allows for up to 30% over-paneling):

https://www.victronenergy.com/mppt-calculator

Rules for over-paneling:

https://www.victronenergy.com/blog/2...ge-regulators/

Short version: Never exceed MPPT rated voltage allowing suitable margin for cold temps and never exceed the PV input current limit.