300w solar on 2006 Sienna. Help me find a charge controller and batteries.

[jrose152]

This 300w Renogy panel is the biggest solar panel I can fit on the roof rack of my 2006 Sienna. I can also fit 2 100w panels side by side but can't fit a 3rd 100w panel up there as well. I originally wanted 2 100w panels to help with the partial shade factor but I'm being told 200w won't be enough for me. I would like to power a 12v fridge(Dometic CF 25 or maybe a CF 35. I haven't decided yet but leaning towards the CF35.), a regular laptop, some led lights, a 12v fan or two, a cellphone quick charger for an android, a charger for an iphone, a nikon d90 camera battery charger, and maybe some other small things I can't think of at the moment but that is the bulk of it. Obviously they all won't be running at the same time but the fridge will be plugged in all the time. This is a weekend warrior but I want to build it right the first time for extended trips that I'm out 1-3 weeks.

I need to find the right MPPT controller for this and some GC batteries either 2 or 4, I havn't decided yet. Someone suggested this Victron controller and it seems to be in the 250$ budget(not that I wan't to spend more then I need to.). I was told I should find a programmable one that is also 3 stage. I also need a hydrometer as well. I could use some help picking these things out. Also, I'm not sure what size MPPT controller to get. 30a or 40a?

 

[highdesertranger]

I don't see why 200 watts won't be enough with a pair of golf carts. I run 2 Engel refrigerators off of 175 watts and occasionally charge my lap top. put a solenoid dual charge system in so you can charge when the engine is running. highdesertranger

 

[WanderingBiker]

thats great advice... LOL but sounds like french to me

 

[highdesertranger]

what part sounds like French? ask questions and we will answer. highdesertranger

 

[John61CT]

Yes the 300W may well not be needed if your solar conditions are reliable good, and especially so if you don't just rely on solar only.

But the shading issue is usually not so critical with a single panel, just don't park where there's any shade

I would go with $300 myself.

The Victron 75/15 SmartSolar is only $130 or so, and you will only be reducing your total output a bit in **peak** conditions, when it's very unlikely to matter since the system needs to be designed for worst case conditions.

1 vs 2 pair GCs already covered in the previous thread,

maybe link to it to give context, avoid repeating everything?

 

[jrose152]

I'm sure I'll add a solenoid to the mix since they are so cheap I don't see a reason not to have one. How much of an advantage would 300w vs 200w give me for what I am trying to do? From what I understand 300w will just charge the batteries faster then 200w, but how much faster? From what I understood in my previous posts some people said 300w is a better choice and 200w is cutting is close. Conflicting advice is spinning me around here. As I understand, 200w will do fine with 2 batteries, but I definitely need 300w for 4 batteries if I go that route. Does my 200w vs 300w just come down to if I want 2 batteries vs 4 batteries? I'm still undecided of I need 2 or 4 batteries. I'd like 2-3 days of power for rain/clouds, but if 2 days means 2 batteries will work and for the 3rd day I'd need 4 batteries I'll probably just stick with 2 batteries since the extra 2 batteries cost is not worth 1 extra day to me.

Still trying to wrap my head around all of this and make the best decision and not come up short. I have around a 1200$ budget for the solar setup if I need to max that out, but that's not to say money grows on trees for me and I want to just throw all the money into the setup because I can. My questions are a little all over but I appreciate the advice/help. Answering these few questions is what's really stopping me from making the decision to go ahead and make the purchase.

 

[Bobflhtc]

I have 3 Renogy 100 watt panels ($130 each) and a Renogy Commander MPPT controller ($250). I did use a Renogy Wanderer PWM controller ($40) for a time. I only switched controllers to be more efficient. I also have 2 Trojan T105's 6 volt batteries($130 each). I use a propane refrigerator.

My understanding is in order to extend battery life the batteries want to be 100 percent charged each day and the next morning still have at least 50 percent charge left. I would use 300 watts if you can comfortably fit them. I like the Trojans(224 amp hours) but they are flooded batteries and mounted on my trailer tongue.

 

[John61CT]

Faster doesn't matter much, you want to get to 100% Full as often as possible, minimum few times a week.

Cloudy conditions or high latitudes short days etc you may go 3 days never getting to full.

Every other day would be much better.

But if you have a genny, or mains easily available, or you're always driving, not so critical.

No one can tell you in advance, too many variables.

"As much as you can fit" is the only safe advice in your scenario, unless you are parked in bright sunshine every day and your fridge only uses 20AH per day.

 

[DLTooley]

The Victron 75/15 will handle 200 watts, 400 if you run in series at 24v. One of the big benefits of the Victrons is the charge and load data simply portrayed on your smart phone, this can help greatly in using your system wisely. You will have an actual number of how much power you are using and how much you are generating under different conditions. Generally, I like driving into town on the third rainy day and use the solenoid to recharge.

The dynamics of the charge cycle are such that you are only using peak panel for a few hours in the morning. Using that extra power in the afternoon for charging a laptop is good.

Knowing your numbers is crucial and there are lots of tradeoffs. Do you have room for a single 200 watt panel that could be doubled if needed? You could do the same with your battery bank, going from 2-4 golf cart batteries, but that decision should be made relatively quickly as consistent battery condition is a plus.

 

[frater secessus]

I vote for 300w,  the Victron 75/15, and 2 6v batteries in series, and the solenoid for a total $800 with flooded batteries if you can ventilate them.  That would be a nicely balanced, functional system that could likely handle anything you'd have room for in a minivan.

I would also watch craigslist for used panels with similar dimensions.  Another thread points to some used 275w going for $150.

300w probably won't charge meaningfully faster, since the longest phase of charging takes hours anyhow. 

The benefits of 300w of panel to the 2 x 6v (225Ah) battery bank will be:

• better yield in marginal conditions. 
  • start charging earlier after sunup, keep charging later as the sun sets
  • less dependence on battery capacity to get you through bad weather.  More panels for the same amount of battery (overpaneling) means you can collect usable power while others weep and curse at their dead iPhones.  If they are nice you can let them charge their phone on your system.     I wouldn't even say 300w:225Ah is overpaneled;  it's a little better than adequate if you forgo the solenoid.
• more power available for loads during the day.  Reduce dependence on battery capacity even further by running heavy loads (like charging laptops, freezing food items, etc) while this extra power is available.

300w would not, IMO, work well with 4 batts (550Ah) unless the solenoid was getting power to them in the morning.  Failure to get batteries fully charged will kill them over time.

If you need to stick to 200w of panel I'd say the solenoid would be required for two batts, unless you drop down to just one 100Ah battery.  Power conservation would need to be followed because you'd have only 50Ah usable at that point.

 

[frater secessus]

Missed the edit window.  

* I think the 100/20 would be a better fit for 300w and is not much more money.

* The Renogy 300w panel referenced above is a 20v panel, not a 24v one.  Note the Vmp on that series of panels is 30v. This will make no practical difference if you run 12v banks.  Will make the same 300w.  I did want to point it out in case you were thinking about going gonzo with a 24v bank.

 

[jrose152]

The Victron 75/15 will handle 200 watts, 400 if you run in series at 24v.  One of the big benefits of the Victrons is the charge and load data simply portrayed on your smart phone, this can help greatly in using your system wisely.  You will have an actual number of how much power you are using and how much you are generating under different conditions.  Generally, I like driving into town on the third rainy day and use the solenoid to recharge.

The dynamics of the charge cycle are such that you are only using peak panel for a few hours in the morning.  Using that extra power in the afternoon for charging a laptop is good.

Knowing your numbers is crucial and there are lots of tradeoffs.  Do you have room for a single 200 watt panel that could be doubled if needed? You could do the same with your battery bank, going from 2-4 golf cart batteries, but that decision should be made relatively quickly as consistent battery condition is a plus.

Will the Victron 75/15 work for 300w? If I ran 200w it would be two 100w panels but it seems like everyone is pointing me towards one 300w panel. I cant do three 100w panels. It won't fit. I do like the idea of having it on my smart phone. Is this a three stage controller? I'm hoping 2 batteries will do what I need it to do instead of purchasing 4. I'm mostly worried about the refrigerator as all the other stuff won't be on day in and day out. Just randomly as needed.

 

[John61CT]

I think the 100/20 would be a better fit for 300w and is not much more money.

Good catch I agree, forgot they'd got that in between, will output everything a 300W collects, IMO overpanel up to 350 even 400 if you got a killer deal.

And also agree OP do NOT consider a 24V bank here.

 

[jrose152]

Missed the edit window.  

* I think the 100/20 would be a better fit for 300w and is not much more money.

* The Renogy 300w panel referenced above is a 20v panel, not a 24v one.  Note the Vmp on that series of panels is 30v. This will make no practical difference if you run 12v banks.  Will make the same 300w.  I did want to point it out in case you were thinking about going gonzo with a 24v bank.

Very good information in both your posts. The amazon link states "Renogy 300 Watt 24 Volt Monocrystalline Solar Panel" so it is 24v. It say's on their website as well it is 24v. Unless I am understanding something wrong. I will run 2 6v batteries into 12v for the system. So I have the panel and controller picked out, what else am I missing? Also would it be possible to run the cable through the rear hatch door and through the grommet to the minivan instead of drilling into the roof? This is what I am hoping to do.

Edit: Do I need to get a 100/20 or a 100/30? Also is it a 3 stage controller or 2 stage? I read I should be getting a 3 stage controller.

 

[John61CT]

amazon link states "Renogy 300 Watt 24 Volt Monocrystalline Solar Panel" so it is 24v. It say's on their website as well it is 24v.

That's just a general label, means Voc the actual spec, is between say 28 and 40V.

With MPPT these nominal labels aren't important, the Victron 100/20 can handle Voc up to say 85-90.

Which is the model to get for your 300W panel.

If you go 2x 100W I'd say two of 75/10 or 75/15 SCs, but be sure it's SmartSolar line so you don't need a separate dongle.

All these quality units are 3 stage controllers, only the old crap ones aren't, haven't seen one for over a decade

 

[jonyjoe303]

how about a 240 or 260 watt panel and an ecoworthy( 100 dollar) 20 amp mppt controller? Those size panels will easily fit on your van, I got a 240 watt panel on my small astrovan and with the ecoworthy I can get about 12 amps on lead acid, and 15 amps when charging lithium. 

The 300 watt panel will charge faster only if the battery isn't close to full. As the battery gets full you might end up getting 12 amps like I do, even though my panel can do 15 amps. You only get the max amps when the battery is low. But the 300 watts will help in cloudy conditions where a 240 panel will give you 5 amps, 300 watts might give you 7 amps.

But for best performance, 20 amp mppt for up to around 260 watts, and 30 amps for 280 and above. I seen a max of 17 amps off of my 240 panel in optimum conditions when charging lithium. You don't want your controller keeping you from getting every ounce of amps possible. 

240 watt will easily run a 12 volt fridge as long as you have good sunshine and keep the fridge set to 40 degrees, your 225 ah lead acid should last you 3 or 4  days during cloudy conditions, a fridge uses about 26 amps total during 24 hours. Even in cloudy conditions you be slowly replacing some amps back into your battery bank.   

The 300 watt panel actually puts out 36 volts, but can be use to charge 12 volts, the controller mppt or pwm with take the voltage down. As long as the controller has got bulk/absorb and float its good. Programmable is even better, if you have voltage drop between the controller and the battery you might need to raise the bulk voltage.

 

[jrose152]

how about a 240 or 260 watt panel and an ecoworthy( 100 dollar) 20 amp mppt controller? Those size panels will easily fit on your van, I got a 240 watt panel on my small astrovan and with the ecoworthy I can get about 12 amps on lead acid, and 15 amps when charging lithium. 

The 300 watt panel will charge faster only if the battery isn't close to full. As the battery gets full you might end up getting 12 amps like I do, even though my panel can do 15 amps. You only get the max amps when the battery is low. But the 300 watts will help in cloudy conditions where a 240 panel will give you 5 amps, 300 watts might give you 7 amps.

But for best performance, 20 amp mppt for up to around 260 watts, and 30 amps for 280 and above. I seen a max of 17 amps off of my 240 panel in optimum conditions when charging lithium. You don't want your controller keeping you from getting every ounce of amps possible. 

240 watt will easily run a 12 volt fridge as long as you have good sunshine and keep the fridge set to 40 degrees, your 225 ah lead acid should last you 3 or 4  days during cloudy conditions, a fridge uses about 26 amps total during 24 hours. Even in cloudy conditions you be slowly replacing some amps back into your battery bank.   

The 300 watt panel actually puts out 36 volts, but can be use to charge 12 volts, the controller mppt or pwm with take the voltage down. As long as the controller has got bulk/absorb and float its good. Programmable is even better, if you have voltage drop between the controller and the battery you might need to raise the bulk voltage.

Why not just go for the 300w panel since I know it will fit? It's about as big as I can possibly go for my van. Then Renogy 300w is just about the perfect size for the roof of my van. I beleive the Victron SmartSolar MPPT 100/20 has everything you are mentioning?

 

[John61CT]

Victron is a much more capable SC, feature set, build quality, efficiency.

 

[frater secessus]

The amazon link states "Renogy 300 Watt 24 Volt Monocrystalline Solar Panel" so it is 24v. It say's on their website as well it is 24v.

A 72-cell (24v) mono panel will have a Vmp around 36-38v.
A 60-cell (20v) mono panel will have a Vmp 30-32v.
This mono panel has 60 cells and Vmp of 32.25V.   
Q.E.D.

It makes no functional difference in your case but the product is incorrectly described (perhaps unintentionally) by Renogy.  I just reported the discrepancy to Amazon.

Update:  d00d, there's a used one right now in Amazon's warehouse in the list for $315.13.   If you have decided on 300w I'd jump on that like a duck on a junebug.   Used panels are fine and a great way to save money.
https://www.amazon.com/gp/offer-listing/B07BK1MG77/ref=dp_olp_all_mbc?ie=UTF8&condition=all

 

[jrose152]

A 72-cell (24v) mono panel will have a Vmp around 36-38v.
A 60-cell (20v) mono panel will have a Vmp 30-32v.
This mono panel has 60 cells and Vmp of 32.25V.   
Q.E.D.

It makes no functional difference in your case but the product is incorrectly described (perhaps unintentionally) by Renogy.  I just reported the discrepancy to Amazon.

Update:  d00d, there's a used one right now in Amazon's warehouse in the list for $315.13.   If you have decided on 300w I'd jump on that like a duck on a junebug.   Used panels are fine and a great way to save money.
https://www.amazon.com/gp/offer-listing/B07BK1MG77/ref=dp_olp_all_mbc?ie=UTF8&condition=all

335$ after tax. The 40$ saving is tempting but I'm not sure it's worth me rushing the decision at the moment. I do appreciate it though. Now if you can find me a cheaper dometic cfx35, we are in business.