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Solar Charge Controller: MPPT Best?
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RBEmerson
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PostPosted: Mon Oct 08, 2012 2:20 pm    Post subject: Reply with quote

Vanagon Nut wrote:
RBEmerson wrote:
......

The cost of MMPT controllers is somewhat of a shaky number. That is, there are inexpensive controllers available but, as if often true, you get what you pay for. A good MPPT controller will probably cost at least the equivalent of a very good meal for two at some place much better than Ruby Tuesday.

That being said, the 10A floor is ...ah... open to reconsideration. Smile


Ok, so max. 10A rating on MPPT output is overkill?

No, quite the contrary - depending on the size and number of panels, as well as the sun angle (panels give the most output when perpendicular to the sun's rays), well over 10A is routine.

IIRC, the 10A figure was given as a "below this point, MPPT controllers aren't worth it". My point is that there's no hard and fast rule on this. It's more a matter of cost v. benefit which is something of a personal choice.

Quote:
Though my grey matter may not yield this, I'm studying up for my "Basic" Ham license, hoping to get 80+% (the latter allows HF use). I anticipate installing some kind of Ham rig, so that + my TF and lower battery voltage due to night use, might add up to more than a 5 Amp load (when transmitting.... with fridge door left open.... Wink ) With this 95W panel, http://www.solar-electric.com/etso95wa12vo.html it seems the max. Amps is 5.13 Amps, but then even with an MPPT, I doubt that number would happen. i.e. maybe a 5A rated MPPT or PWM would suffice.

Are you planning on a QRP (low power) rig or something heavier? If you want real power, you need some serious (e.g., at least 200 a/h and preferably at least double that) battery power and you should plan on working only at the upper end of the battery charge. For example, my 150 watt marine SSB (Icom IC-M802, also ham capable) pulls down a lot of current when transmitting (fused at 35A)
Quote:
In terms of quality, it seems to me that some charge controller makers are "ma & pa" type set ups. Maybe some actually make their products in-house which might allow for better QC? i.e. from Solar Controllers Inc. FAQ"

I suppose, but companies like Blue Sky or Morningstar are hardly "ma & pa" companies. As always, the wise consumer does some research before buying.

[...]
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Vanagon Nut
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PostPosted: Mon Oct 08, 2012 2:38 pm    Post subject: Reply with quote

Much thanks RBEmerson

At the very least, will run substantial + wire behind cabinets (they're out currently) for future loads. Not sure what rig I'll run. Depends on my mark! Wink If I qualify for HF, maybe I could get away with a lower power rig for night time DX. Then again, the main reason for a rig would be for comm if out of cell phone range. I don't know enough about transceivers yet. And now I'm getting mostly OT.

I see what you mean re amperage rating of a charge controller. I need to clearly ID my electrical needs. If I'm into 2 panels, the $ difference between MPPT and PWM could be spent on metering or at the very least, a flexible properly rated PWM controller. ..... as has already been suggested or inferred. Wink

Neil.
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RBEmerson
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PostPosted: Mon Oct 08, 2012 4:01 pm    Post subject: Reply with quote

Vanagon Nut wrote:
Much thanks RBEmerson

You're welcome!
Quote:
At the very least, will run substantial + wire behind cabinets (they're out currently) for future loads. Not sure what rig I'll run. Depends on my mark! Wink

Depending on the length of the run, you're looking at 10 AWG at a minimum and more likely heavier. Even over a relatively short run, voltage drop at this current level matters.
Quote:
If I qualify for HF, maybe I could get away with a lower power rig for night time DX. Then again, the main reason for a rig would be for comm if out of cell phone range. I don't know enough about transceivers yet. And now I'm getting mostly OT.

Time to do some serious homework here.

Quote:
I see what you mean re amperage rating of a charge controller. I need to clearly ID my electrical needs. If I'm into 2 panels, the $ difference between MPPT and PWM could be spent on metering or at the very least, a flexible properly rated PWM controller. ..... as has already been suggested or inferred. Wink

Neil.

Er, PWM is almost certain to be a major RFI source. And you won't be getting the most out of your panel.

Metering... unless you want to get involved with "Amp-hours used" monitors (e.g., Xantrex Link Pro or Link Lite), a simple ammeter and voltmeter will do you.
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Vanagon Nut
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PostPosted: Mon Oct 08, 2012 4:13 pm    Post subject: Reply with quote

RBEmerson wrote:


Quote:
... the $ difference between MPPT and PWM could be spent on metering or at the very least, a flexible properly rated PWM controller. ..... as has already been suggested or inferred. Wink

Neil.

Er, PWM is almost certain to be a major RFI source. And you won't be getting the most out of your panel.

Metering... unless you want to get involved with "Amp-hours used" monitors (e.g., Xantrex Link Pro or Link Lite), a simple ammeter and voltmeter will do you.


Edit:

RBEmerson wrote:

Quote:
If I qualify for HF, maybe I could get away with a lower power rig for night time DX. .....

Time to do some serious homework here.



Yes! I have been! It's tougher than I thought. hamstudy.com is helping. I'm scoring in the high 70's on the test generator but I haven't done this kind of studying in DECADES so..... Wink

Yes! Thanks for reminder. Forgot about the RF interference issue. And yes; had thought to install a meter or two. Thanks.

Neil.
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PostPosted: Mon Oct 08, 2012 4:53 pm    Post subject: Reply with quote

Vanagon Nut wrote:
With this 95W panel, http://www.solar-electric.com/etso95wa12vo.html it seems the max. Amps is 5.13 Amps, but then even with an MPPT, I doubt that number would happen. i.e. maybe a 5A rated MPPT or PWM would suffice.


I just put my 45W panel in full sun today, and I got a short-circuit current about 5% above the specified amount. So yes, this happens.

Also, make sure where the measurement is taken for the rating. 5A on the panel side (before the MPPT has it's chance to convert volt into amps) isn't the same as 5A on the battery side.
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PostPosted: Mon Oct 08, 2012 4:58 pm    Post subject: Reply with quote

RBEmerson wrote:
Er, PWM is almost certain to be a major RFI source.


MPPT uses PWM too (Pulse Width Modulation). MPPT adds a large inductor so RFI could potentially be even greater than simple PWM. But then again the simple PWM controller will cause current surges in the wires going to the battery. Both types will have RFI, I don't think this should be a point of contention though.

On the "shaded panel" problem, as mentioned it's complicated. Some panels have individual bypass diodes per cell; not many do though. In this case, as long as the overall voltage is still above battery voltage, either MPPT or PWM controller will still charge. Most all MPPT controllers just have a "buck converter", so input voltage needs to be higher than the output. In fact in this condition a PWM controller will close the efficiency gap.
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PostPosted: Mon Oct 08, 2012 5:11 pm    Post subject: Reply with quote

FWIW, the Blue Sky SB6024 is silent on my SSB radio. I wish I could say as much for an old Heart inverter/charger. Evil or Very Mad
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PostPosted: Tue Oct 09, 2012 4:27 pm    Post subject: mppt vs. pwm Reply with quote

what most people dont realize is that if you go with pwm and you use
solar panels with higher voltages the pwm will not work as efficiently as mppt or may not work at all. you can use any voltage panels with the mppt and the larger panels and higher voltage panels are usually cheaper/watt than the 12 volt panels (36 cell).
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r39o
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PostPosted: Tue Oct 09, 2012 5:42 pm    Post subject: Re: mppt vs. pwm Reply with quote

pushkick wrote:
....mppt and the larger panels and higher voltage panels are usually cheaper/watt than the 12 volt panels (36 cell).

Think grid tie panels here.

Last year I bought 50w mono 48v nominal panels for less than a dollar per watt. That was a smoking deal at the time and is about what you pay now.

The higher voltage panels make a lot of sense and is the reason I use a 150 v MPPT controller.
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mappley
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PostPosted: Wed Oct 31, 2012 1:08 pm    Post subject: Reply with quote

When I get around to solarizing my westy I'll probably get this:

http://www.amazon.com/MISOL-regulator-remote-display-Controller/dp/B008JNJ2RW

For the panel array I'd maximize the voltage, meaning I could use thinner gauge wire from array to the multiple power point tracking (mppt) charge controller, maximizing the controllers effectiveness. (Where mppt really shines is with a high voltage solar array to a lower voltage battery bank.)

To maximize the voltage you could either buy high voltage panels, or wire lower voltage panels in series, ie. pos lead to negative lead, like batteries in a flashlight. This controller accepts input voltage of up to 100 vdc. Could be overkill, but too much power? that's a problem I can work around.

I have no experience with the above model, could be poop- but for the price, which includes a cool little display screen and lots of buttons ( oooh- buttons) I'm willing to suggest it as an option.

For the batteries I want to go with a 120 amp hour AGM sealed cell tower battery. Shaped more like a very large book than a brick, they are zero maintenance and can be mounted thin and tall (mirrored closet) or flat and wide (under couch). Might even mount under chassis.

Hope this was helpfull-
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PostPosted: Wed Oct 31, 2012 7:29 pm    Post subject: Reply with quote

mappley wrote:
When I get around to solarizing my westy I'll probably get this:

http://www.amazon.com/MISOL-regulator-remote-display-Controller/dp/B008JNJ2RW

For the panel array I'd maximize the voltage, meaning I could use thinner gauge wire from array to the multiple power point tracking (mppt) charge controller, maximizing the controllers effectiveness. (Where mppt really shines is with a high voltage solar array to a lower voltage battery bank.)

To maximize the voltage you could either buy high voltage panels, or wire lower voltage panels in series, ie. pos lead to negative lead, like batteries in a flashlight. This controller accepts input voltage of up to 100 vdc. Could be overkill, but too much power? that's a problem I can work around.

I have no experience with the above model, could be poop- but for the price, which includes a cool little display screen and lots of buttons ( oooh- buttons) I'm willing to suggest it as an option.

For the batteries I want to go with a 120 amp hour AGM sealed cell tower battery. Shaped more like a very large book than a brick, they are zero maintenance and can be mounted thin and tall (mirrored closet) or flat and wide (under couch). Might even mount under chassis.

Hope this was helpfull-

You can get that controller and monitor panel for less on eBay or at http://www.yoosmart.com

I have the 10A version. See my earlier posts to this thread.
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PostPosted: Sat Jul 27, 2013 12:14 pm    Post subject: Reply with quote

Been doing some more reading/research.

re: EPsolar controllers.

I was curious if this Viewstar PWM controller

http://www.yoosmart.com/vs2024n-20a-solar-charge-controller-12v-24v.html

was made by EPsolar. Seems so:

http://www.epsolarpv.com/en/index.php/Product/pro_content/id/166/am_id/136


Googling "Viewstar" or "EPsolar" gets lots of hits for company websites and youtube vidoes selling this stuff but few independent reviews.

I know r39o has been happy with his EPsolar MPPT, but have others been happy with the QC of their EPsolar PWM controller?

Is it true that an MPPT controller will track best when connected to matching panel types/size as opposed to being connected to mismatched solar panel types? (mono and poly panel)


Neil.
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PostPosted: Sat Jul 27, 2013 3:35 pm    Post subject: Reply with quote

I went with this controller to go with 100W grape solar mono panel. Very very pleased with the setup. Genasun GV-10, best price I found was at the ALT E website.

http://genasun.com/all-products/solar-charge-contr...ontroller/
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PostPosted: Sat Jul 27, 2013 4:34 pm    Post subject: Reply with quote

I see they also have one for flooded lead cell batteries:

http://genasun.com/all-products/solar-charge-contr...ontroller/

Seems their controller draws less power than most at 0.9 mA.

And from their web page:

"High-Speed MPPT: Always on Target
Not all Maximum Power Point Tracking controllers were created equally. Most use a sweep and sleep method that scans the entire voltage range every 30-60 seconds. That's okay for a clear day, but traditional controllers are constantly off target during changing cloud conditions exactly when power is scarce and needs the most. Genasun controllers adapt to changing light conditions 20 times every second. ..."
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PostPosted: Sat Jul 27, 2013 4:45 pm    Post subject: Reply with quote

I have mine hooked up to a 4D AGM under the back seat and it also charges the flooded start battery through a Blue Sea ACR.
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PostPosted: Sat Jul 27, 2013 5:40 pm    Post subject: Reply with quote

jstar89crx wrote:
I have mine hooked up to a 4D AGM under the back seat and it also charges the flooded start battery through a Blue Sea ACR.

Which controller is that?

I am going see if I tacan get a timing rate of PV input for the EPSolar Tracer MPPT controllers.

As an aside: WOW, where you mount that 4D monster?

Pictures or it ain't real.....
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PostPosted: Sun Jul 28, 2013 1:47 pm    Post subject: Reply with quote

Sorry to take the post on a tangent but, to mount the 4D I blew out the under seat heater since that is where my Webasto outlet is and the factory heater was never used.

Battery along with new face frame with factory heater outlet deleted.
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Charger controller and ACR above battery.
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Fuse Block
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Webasto control board and TDI ECM and relays.
Image may have been reduced in size. Click image to view fullscreen.

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