Solar charge controller?

[dreadlocks]

All the information you seek is contained within the spec sheet: https://www.victronenergy.com/uploa...charge-controller-MPPT-100-30-&-100-50-EN.pdf

partictuarly the fine print,

1a) If more PV power is connected, the controller will limit input power.

In these instances stop referring too and worrying about voltages/amps.. its watts you need to use, voltages and amps are going to be all over the place in a solar setup.. but wattage will remain consistent... ie, 12v * 10A = 120W is the same as 24v * 5A = 120W...

But yeah, the Victron units you can hook 800W up to a 300W controller, and it will output 300W max with no problem, as long as you dont go over the controllers maximum voltage.. this would be advantages if you fix your panels to a roof or something and then tend to park in the shade.. would give you more power out of overcast/diffuse light if thats where you spend most of your time, thats how I'm doing my solar setup.. I'm wanting 100W-200W in rather poor (ie, forest) lighting conditions, so I'm installing ~600W of panels and designing it with this in mind.

 

[Howard70]

I
.... Would the 30amp output controller still work? just be limited to 30 amps of output? or would this cause a problem for the controller?

I would guess it depends upon the controller. I think the excess energy has to go somewhere and is probably dissipated as heat. You might contact technical support of the solar controllers you're considering and ask them that question.

At first I wondered why anyone would want to do that - have an array of panels that produced more than the controller could feed to the batteries. After thinking about it, it actually made sense to me (I'm pretty slow...). Our solar set up is considerably over powered for our needs under optimal conditions (more charge capacity than we need to offset our use), but under poor conditions it's adequate. Thus you might have an array of panels large enough to fill your charging needs in poor conditions (low angle sun, cloudy skies, etc) and simply let the system trim the excess in optimal conditions.

Some solar controllers (Blue Sky Energy Systems come to mind) have auxiliary outputs for excess energy (run a fan, charge another battery, etc.).

Howard

 

[dwh]

Well, the 100/30 has a maximum solar short circuit current rating of 35a, and the manual says higher than that may damage the controller.

It also says operating temp -30c - +60c, but full rated output only to +40c, so it obviously has some ability to throttle the current.


To regulate power flow, there must be a load of some sort, or there's no flow to regulate. A PWM is just a high-speed chatterswitch that connects/disconnects the source to the load. It can maintain precise voltage and current flow by quickly pulsing current and can vary the length/timing of the pulses. MPPT units also have switches like that.

Any switch will have a max current rating which the contacts can handle without burning out. Any manufacturer of quality gear is going to use a switch with a rating higher than actually needed. Dunno what the ratings are for the internal switches in the 100/30...40a? 50a? Dunno.

So it could probably handle the 40a in your example. Maybe forever, or maybe only for a while. Or maybe only as long as it doesn't get too hot.

 

[ebrabaek]

I have now used the vitron 10 amp blutooth controller for one season.
I absolutely loves it. To the point that I use the output for it to connect the fridge and it shows the power consumption and history thereoff.
It is a great charge controller

 

[dreadlocks]

Well, the 100/30 has a maximum solar short circuit current rating of 35a, and the manual says higher than that may damage the controller.

you would have to grossly oversize to hit 35A on the solar side, for example the 300W house panels I've been eyeing have a max power output of 9A (w/VOC of ~40v), so even with 3 of em (~900W,27A) hooked up to a lil 100/30 it would still not exceed the 35A current rating on the solar side.. you could probably get 6 panels (1800W) if you had 3 parallel groups of 2 in series (3x9A@80v).. not that you ever would want too, but it'd be within the amp ratings.

but with lower voltage panels I could see you running into troubles maxing out the ~30A bus on the solar side when trying to overbuild.. so if your overbuilding, use higher voltage solar (12v in series or house panels) to lower the amps..

As long as you can stay within that you can size your charge controller to your battery and still overbuild for less than ideal conditions.. lets say your running a typical dual battery lead bank on a 100/30 with 600W of solar backing it up, this would be effectively the same as a 100/50 and the same panels, since your bank would be lucky to take even 30A of charge current let alone 50A..

 

[Fatboyz]

Interesting read. I'm just building my system with 3 100 watt panels. Sounds like the Victron is the way to go. I too am a real solar newbie and this has been a good read.

 

[outwestbound]

Most would be a lot better off tilting their panels rather than worrying about a few extra watts from MPPT.

But how many bother with that? Not many. So they flat mount the panel and then worry that they need MPPT to improve efficiency?

Meh.

It's not just that I can be lazy at times, but getting up on the roof to tilt the panels just adds risk of injury. I'm over 55, so if I can avoid the risk, why not. On my big rig, I have 6, 160w panels with the fancy tilting mounts from AM Solar. I've never tilted them. I just added a couple panels and don't worry about tilting them, because I'm lazy.

Now on a smaller rig, as you say, having fewer panels can make tilting really advantageous and it's easy to do. Most of the folks I know who tilt say that they are getting 20-25% increases in harvest (assuming also they understand how to orient their vehicle to the sun).

 

[outwestbound]

All the information you seek is contained within the spec sheet: https://www.victronenergy.com/uploa...charge-controller-MPPT-100-30-&-100-50-EN.pdf

partictuarly the fine print,


In these instances stop referring too and worrying about voltages/amps.. its watts you need to use, voltages and amps are going to be all over the place in a solar setup.. but wattage will remain consistent... ie, 12v * 10A = 120W is the same as 24v * 5A = 120W...

But yeah, the Victron units you can hook 800W up to a 300W controller, and it will output 300W max with no problem, as long as you dont go over the controllers maximum voltage.. this would be advantages if you fix your panels to a roof or something and then tend to park in the shade.. would give you more power out of overcast/diffuse light if thats where you spend most of your time, thats how I'm doing my solar setup.. I'm wanting 100W-200W in rather poor (ie, forest) lighting conditions, so I'm installing ~600W of panels and designing it with this in mind.

Chasing sun in the forest is a challenge. On this little motorhome in my profile pic (23'), I have a good LG 300 watt high voltage panel into a Blue Sky MPPT 3000i. Then I added a little Renogy Rover MPPT controller with a 160 watt flexible panel (I only care if it lasts 1.5 years or so, I know flexible is marginal) and a Sunpower foldable 120 watt ground deployable panel. These 2 are in parallel. I'm figuring in worst case, I can reach out 30' with the ground unit. I cut the PWM and cabling that came with the Sunpower off and upsized the wire significantly. It's performing to its label spec. I haven't used it yet in action. This system has redundancy in the event of failure, but isn't cheap. It's a hobby.