solar panel hookup

[benneufeld]

hello i have a very interesting dilemma i am hoping to finally wire my solar panel system in completion so i may finally successfully boondock without issues as i don’t want a outside electrical hook up
and want access to my water heater which is both electrical and propane powered as well as an electrical oil heater to not waste gas. my RV is a fleetwood bounder 94 model with a washer dryer combo it has two furnaces and air conditioners hooked up. i don’t plan to use all appliances at once of course i just want to live comfortably with no issues or need for electrical hook up. id also like to use a HYBRID inverter charger controller for minimal space usage if anyone could recommend the best model with some bluetooth capabilities. i’ve already tried the RENOGY hybrid model and it has a few issues that people have spoken about online so whatever model you recommend that can top that would be amazing i also currently have a single 12v lithium battle born battery which i know will need to be upsized to a bigger setup, likely two 12v 100amp lithium batteries if you can give the best recommendation of a single 48v or 2 24v lithiums and maybe a reliable cheap brand to use as well. i’ve attached the specs of my solar panels for reference below, thanks again for all your help it’s really appreciated.

My issue is i own three 455 watt FINNING cat panels, they are rated for 48v output and 20amperage rating as well at max.

series is better for wiring when u need a minimum voltage output rating and it’s more efficient this is not an issue in fact i have too much voltage for my charge controller. if i wire in parallel though my amp rating will be way too high for the solar panel wire already wired through the Rv which i believe is 12 gauge.

i’m only hooking up two panels out of fear i’ll overload the system using the third. but please give advice on what i should do for best result.

 

[benneufeld]

also would like to know what is better a 48v lithium battery for 50amps like what renogy offers or are two 24v for 50amp better? as price is somewhat a factor but not entirely if it sacrifices more bang for your buck. thanks.

 

[Kevin Means]

Welcome to the RV Forum. You mentioned the possibility of using Li batteries with different voltages, so I'd suggest settling on that first. Upping your 12 volt system to run off 24 or 48 volts is not as easy as it sounds. All of your 12 volt devices will need a converter to run off higher voltages. Doable, but not real practical.

I tried to blow up the images sizes of your solar panel spec sheets, but they got too fuzzy to read. If you can fit those panels on your roof, there's no reason they shouldn't work well together. You'll need a solar controller that is capable of handling the amperage, but there are several controllers out there that would work fine.

If you're going to use lithium batteries, I'd recommend getting a converter with lithium battery settings to charge the batteries. They aren't hard to find. 48 volt panels will work fine with an appropriately sized controller. You'd certainly want an MPPT controller, but those are everywhere too. The controller will convert excess voltage to amps to charge your batteries faster - even if you stick with a 12 volt system.

If you're going to run your panels in series, I'd recommend using 10 gauge wire. It's generally rated up to 30 amps, while 12 gauge wire is generally rated to 20 amps. 12 gauge wire would probably work fine, because if your panels are flat-mounted on the roof, they're not likely to see max output very often, but better safe than sorry.

Kev

 

[benneufeld]

hello kevin, i will repost the photos as full
images of that will help at all.

thanks for the advice on the gauge of wire to use. the guy before me already wired 12 gauge wire down to bith batteries. but my panels are each rated for 10.92 amps at max output and 8.75 at minimal output so if i wire them in parallel the amperage won’t go over the 20 amp rating by a lot but it may go over a little bit will that be damaging? to the wire if it’s just a little bit over?

also in regards to the hybrid inverter i’ve heard good things about the GROWATT SPF 3000. my panels obviously are a little under size for a 3000 watt inverter but will that make the system more efficient if it’s not running at max power 24/7? thanks for your help really
appreciate it

ben N

 

[Kevin Means]

Okay... 10.92 amps sounds more like I would have thought. I suggested 10 gauge wire, because your first post said your panels put out 48 volts and 20 amps - at least, that's what I understood, and I couldn't read the data in the images. You can stick with 12 gauge wire, since your panels max out at 10.92 amps - not 20 amps.

if you wire your panels in series. The voltage will triple (with 3 panels) but the amperage will remain the same - well within what 12 gauge wire can handle. An MPPT controller will convert the extra voltage to amps, which will help charge your batteries faster, and a bit sooner and later in the day.

The purpose of an inverter is to invert a lower voltage to a higher voltage. In the case of RVs, that usually means you're inverting 12 volts DC (from your house batteries) to 120 volts AC to run AC appliances. That's a little misleading, because most RV battery banks can't power things like rooftop air conditioners and washer/dryers. Unless you're doing something really fancy, your inverter doesn't have much to do with your solar array. Solar is primarily used to recharge your batteries, and your batteries power DC systems and AC systems IF your have an inverter.

Kev

 

[benneufeld]

Okay... 10.92 amps sounds more like I would have thought. I suggested 10 gauge wire, because your first post said your panels put out 48 volts and 20 amps - at least, that's what I understood, and I couldn't read the data in the images. You can stick with 12 gauge wire, since your panels max out at 10.92 amps - not 20 amps.

if you wire your panels in series. The voltage will triple (with 3 panels) but the amperage will remain the same - well within what 12 gauge wire can handle. An MPPT controller will convert the extra voltage to amps, which will help charge your batteries faster, and a bit sooner and later in the day.

The purpose of an inverter is to invert a lower voltage to a higher voltage. In the case of RVs, that usually means you're inverting 12 volts DC (from your house batteries) to 120 volts AC to run AC appliances. That's a little misleading, because most RV battery banks can't power things like rooftop air conditioners and washer/dryers. Unless you're doing something really fancy, your inverter doesn't have much to do with your solar array. Solar is primarily used to recharge your batteries, and your batteries power DC systems and AC systems IF your have an inverter.

Kev

hey kev thanks for the advice on that..

an update:

i bought a growatt spf 3000 splitphase that requires 48v mandatory. Now bear with me as i’m a little green at this. but if you plan to invert to 120v then one 48v or two 24v at 100ah is best right? as opposed to a bunch of 12v 100ah’s.

My battery storage is also a bit limited so i was hoping to wire two 24v 100ah and get a 48v bank.

Now with that thought in mind..

what are your thoughts on the inefficiency of inverting from 48v battery bank to a 120v for appliance usage and occasionally heating a hot water tank? is that sustainable with 3 455w panels (producing around 455-1000w/day) as long as your not running an AC all day long (which I never use anyways cause i live in CANADA)

would love to know your thoughts on this.
thanks again!

 

[Mark_K5LXP]

if you plan to invert to 120v then one 48v or two 24v at 100ah is best right?
as opposed to a bunch of 12v 100ah’s.

That depends on what grade of batteries you select, and what degree of performance (power draw & duration) you're expecting. Without some numbers for size, weight, cost and power delivery it would be difficult to name a particular "best" block configuration.

...the inefficiency of inverting from 48v battery bank to a 120v for appliance usage and occasionally heating a hot water tank?

It is what it is - if the goal is to heat water with electric solar panels then the efficiency is just part of the system calculation and component selection. Or, working backwards you figure out the net power delivery of your solar, factor conversion efficiencies (battery and direct) and there's some number of watt hours available. Convert Wh to Btu to see how many gallons of water will be heated from/to a given temperature.

is that sustainable with 3 455w panels

Depends entirely on how many gallons of hot water you want a day. Being in Canada (high latitude) and winter (low insolation) I don't think you'll have a lot of hot water. But "a lot" is relative, maybe it's enough. Run the numbers.

Mark B.
Albuquerque, NM

 

[AstroBob]

I find this handy : Solar Panel Series & Parallel Calculator - Footprint Hero

 

[jag32266]

You asked about a cheaper version of batteries,.. Eco-Worthy might be one for you. I have two of their 260Ah. HTH. Lithium Batteries | ECO-WORTHY

 

[milon]

hello i have a very interesting dilemma i am hoping to finally wire my solar panel system in completion so i may finally successfully boondock without issues as i don’t want a outside electrical hook up
and want access to my water heater which is both electrical and propane powered as well as an electrical oil heater to not waste gas. my RV is a fleetwood bounder 94 model with a washer dryer combo it has two furnaces and air conditioners hooked up. i don’t plan to use all appliances at once of course i just want to live comfortably with no issues or need for electrical hook up. id also like to use a HYBRID inverter charger controller for minimal space usage if anyone could recommend the best model with some bluetooth capabilities. i’ve already tried the RENOGY hybrid model and it has a few issues that people have spoken about online so whatever model you recommend that can top that would be amazing i also currently have a single 12v lithium battle born battery which i know will need to be upsized to a bigger setup, likely two 12v 100amp lithium batteries if you can give the best recommendation of a single 48v or 2 24v lithiums and maybe a reliable cheap brand to use as well. i’ve attached the specs of my solar panels for reference below, thanks again for all your help it’s really appreciated.

My issue is i own three 455 watt FINNING cat panels, they are rated for 48v output and 20amperage rating as well at max.

series is better for wiring when u need a minimum voltage output rating and it’s more efficient this is not an issue in fact i have too much voltage for my charge controller for rv solar solutions. if i wire in parallel though my amp rating will be way too high for the solar panel wire already wired through the Rv which i believe is 12 gauge.

i’m only hooking up two panels out of fear i’ll overload the system using the third. but please give advice on what i should do for best result.

Hello. I've decided to add 400W of solar to my rig and have been researching my options. I know I want monocrystalline panels (rigid) and am going to use a Victron MPPT controller. I've looked at several panels and boy is it confusing so I thought I'd throw it out there and ask the group what they're using or what they've found to be a good panel to use? or what they've found after installing current panels as technology changes rapidly.

Any input for my system design or recommendations will be greatly appreciated and read!

Thank you!!!

 

[Laura & Charles]

Hi Milon. There’s several members here who very knowledgeable about building solar systems. I’m not one of them. But I wanted suggest you start a new thread. It’s very easy for anyone see a fresh post (within a week or so) and read the first few posts and scroll to end and comment… completely missing your post and your particular questions. To get the best and most focused information, a new thread is always a good idea.

 

[RochetBrianna]

For your battery and inverter setup, if you’re thinking about using 120V appliances often, going with a 48V system and a good-sized battery bank could be a smart choice.

 

[RedForeman]

You may not have noticed, but this thread started last December. I imagine the OP found a solution by now.

But, since you kicked it to the top, I will remark on one of the OP problems nobody else mentioned. Maybe someone in the future with a similar dilemma that finds this thread may see a solution. That being how to run 4x455W 48V panels on existing 12ga wiring. The solution is: use two charge controllers, each hooked to two panels in series. The battery bank won't care if there's more than one controller feeding them. Just have to make sure whatever charge controllers are selected are compatible with the chosen DC voltage 12,24, or 48, and high enough voltage capacity on the PV side to work with the panels (100V minimum if I'm reading the specs right).

TLDR: @Mark_K5LXP has the correct response. Available data points for an "easy" answer isn't here. OP should have consulted with someone to thoroughly analyze his use case and budget, then use that to recommend build details.

Just my opinion, a fully utility-quality pv system is only as practical as you have money to spend, and room to safely install it all. 48V on the DC side is probably the best choice and safest, but components are more expensive and less available. 24V is a lot better in those regards, at the expense of wiring and switching efficiency. IMO a 12V system for anything over 2000W inverter capacity is a fire risk. Still doable to go big if you use more than one inverter, all it takes is more wiring and space. So you really aren't saving anything by avoiding a converter to feed the 12V stuff on the camper with a higher voltage battery bank.

Then after all that, a run of cloudy days plus low sun angle and fewer hours of sun in the winter, you may still need a gas powered generator or shore power, how soon depending on how burly your battery bank is. This is where compromises matter. Such as whether you run a more efficient and less convenient propane or diesel furnace, or burn thru your capacity with heat pumps and electric space heaters.