Mppt and solar

whgoffrn · Post by **whgoffrn** » Tue Jul 03, 2018 8:48 pm

Well I somehow accidentally broke my 100w solar panel this last weekend .....flexible...yeah right anywho since I'm already replacing it with another 100w panel I decided to go ahead and splurge for an mppt controller and just curious what anyone thought of the epever models.... they are the cheap mppt at just a 150 for the controller and the meter....and just wondered if I'd notice any or much different ....my cheap pwm controller and 100w panel seems to do ok at powering it now but I never seem to see it completely in float mode with the fridge on .... I was hoping an mppt would allow me to maybe even crank the temp setting down a bit while the sun is up so the fridge runs less when the sun is down conserving even more power .....but I wonder if I'd notice much or any difference in an mppt vs pwm on such a small scale of 100 watts and 2 x 29 group batts

sailboatmike · Post by **sailboatmike** » Tue Jul 03, 2018 10:39 pm

From the reviews I have watched on YouTube the EPEVER MPPT controllers are the best of the cheaper units but you do need the meter to use all the functionality.

They claim (the reviewers) that you get about 15% more from a MPPT than a PWM. I would think (I'm no expert) that at 100 watts it would make a real difference, but you could in theory just use 120 watt panel and the PWM and get about the same output as 100 watts and the MPPT.

Of course doing this (120w with PWM) would be cheaper but space wise it may not really practical on a 26 foot boat.

kurz · Post by **kurz** » Tue Jul 03, 2018 11:51 pm

Maybe other know better, but the best output with mppt regulators you have when you use 2 solar panels in serial mode. So you get higher voltage that the mppt regulator can convert in 14.4V or 14.8V.
Example: If you have serial mode, even when V is low, you can easily get 20V. So the mppt regulator can transform this high V in lower 14.4V but increases the Amperes. The pwm regulator just cuts the Volts highter than 14.4V and does not increase the amps.

Maybe in best sunlight condition the difference is not to big. So as I have two 50W panels I invested for the mppt....

Gazmn · Post by **Gazmn** » Wed Jul 04, 2018 1:24 am

While I'm Ditto on Kurz & SMike - & I have the above controller, I'm switching it out based on Capt Paula Ke's word From this convo...
I already purchased the ones she recommended - & mind you - I didn't know of any interference. PM me for a freeo Ghoff -I owe you from Duck Key info. Re: my old ones, or anyone can second that emotion, pending his reply

PS, How the hull did u break ur panels??

Inquiring minds would Love a post

PS, PS: You Guys are the greatest!

Love u Guys/Gals- Captains

kadet · Post by **kadet** » Wed Jul 04, 2018 3:15 am

Maybe other know better, but the best output with mppt regulators you have when you use 2 solar panels in serial mode. So you get higher voltage that the mppt regulator can convert in 14.4V or 14.8V.

Fortunately some people do know better

A typical 12v Panel puts out between 18-21V so an MPPT controller will convert the extra voltage to higher amperage at lower charging voltages. You do not need to put panels in series to get the benefit though even higher voltages will give greater efficiency and less loss over the cable runs.

EPEVER are good value genuine MPPT controllers with proper inductors I have used a couple in my solar installations and they have performed flawlessly and are good value for money.

whgoffrn · Post by **whgoffrn** » Wed Jul 04, 2018 4:06 am

Good to know it should add some extra juice to the battery hopefully.... amazon should be delivering Friday....
How did I break the panel ...wow what a story...a pitiful story... in 20 years old boating I've never had to call the coast guard till this last weekend but yeah... I did....to have a BEZERK drunk ex removed from my boat.... while I'm not against alcohol I'll have 1 to 3 beers I keep myself in control of my actions and she has a dependancy problem....one I've known about for a while but I had NEVER seen as bad as this weekend she drank an entire bottle of vodka and went absolutely bezerk alcohol rage for no reason and started tearing up stuff...kicked the ac through the door broke my pieces I had cut to form around the ac... broke the solar panel threw tablets in water went just bezerk tearing up anything she could get her hands on and throwing anything within reach in the water ... I leave for the keys in 8 days and the purpose of the trip was a shake down cruise to see what needed fixed and to repair the couple things that I knew needed done like solder the wire to the vhf mast antenna connection cause I wasnt paying attention and let the mast down last year with it still connected and ripped it out ...several other minor things....and I am trying to fabricate a way to attach 3 flounder pro 5000 underwater lights to an inflatable dinghy because I intend to try my hand at lobster bully netting from the inflatable dinghy at midnight on start of lobster season.......so while I did have 2 or 3 minor projects to work out before I leave now I have a LONG LONG list of repairs and expenses to try to scramble and put together all because of alcohol and some peoples inability to control themselves......so yeah after 20 years of being on the water I had to call for assistance from coast guard to remove a bezerk crazy person from my boat . Rant over sorry obviously I'm still very miffed about the whole situation lol

sailboatmike · Post by **sailboatmike** » Wed Jul 04, 2018 5:38 am

Alcohol is a horrible thing when it gets out of control, that was the major reason my first wife and I broke up, she could polish off a bottle of vodka in a night without a problem, and like many she just became totally obnoxious when on a binge.

This is one of the reasons I don't drink (well much, maybe a beer every couple of months), after seeing someone like that I always think to myself I never want to be like that.

kurz · Post by **kurz** » Wed Jul 04, 2018 6:22 am

@Kadet
I agree with you 100%.

For me the advantage with 2 50W panels in serie and mppt controller is important as I want to inrease the output in bad conditions like morning/evening or when the sun is shaded.

So the 2 panels in serie will longer get Volts over 15V and an mppt controller can squeeze out the last drops.

In full sun I have to much energy anyway.

kadet · Post by **kadet** » Wed Jul 04, 2018 9:18 pm

Re: Mppt and solar
Post by kurz » Wed Jul 04, 2018 11:22 pm

@Kadet
I agree with you 100%.

For me the advantage with 2 50W panels in serie and mppt controller is important as I want to inrease the output in bad conditions like morning/evening or when the sun is shaded.

So the 2 panels in serie will longer get Volts over 15V and an mppt controller can squeeze out the last drops.

In full sun I have to much energy anyway.

Actually solar panels are current sources not voltage sources. When shade hits them the first thing that happens is the current drops. It is possible for a panel to put out its full Voltage and have zero current. In fact it happens every morning when the first rays of light cause the panel to hit Voc @ 0 Amps.

The MPPT power advantage is found at maximum power point of demand (hence the name) which will be at the lowest battery Voltage (discounting load draw), not the Absorb level. This will occur regardless of whether the panels are in series or parallel.

Series is only an advantage when you have partial shading of one panel that causes the isolation diodes to kick in. In this case it might be possible to squeeze or lesson the loss on the unshaded panel by using all available voltage to keep above the charging point.

Shade is never good and should be avoided whether in parallel or series.

Cougar · Post by **Cougar** » Thu Jul 05, 2018 12:26 am

I have two 40 watt panels in parallel to a Victron MPPT charger, attached to the cockpit life lines. In this setup at least one panel will almost always benefit from direct sunlight without any shading. The drawback of having panels in series is that when one has even only partial shade, the whole array will be affected. The big advantage of MPPT is that they get the utmost out of the panels in less than ideal conditions, which is most of the times.

Bearing in mind that the Dutch climate is rarely very hot, I can leave my fridge on for 24/7 without the need for shore power.

eodjedi · Post by **eodjedi** » Thu Jul 05, 2018 12:24 pm

I use this MPPT controller and I love it. Connects to my phone with bluetooth and gives me a history of daily solar output and usage.

https://www.amazon.com/gp/product/B075N ... UTF8&psc=1

Gazmn · Post by **Gazmn** » Fri Jul 06, 2018 7:58 am

Sorry for the hard luck & circumstance. I'd go with the one Capt Paula referenced from my other entry. Since you're redoing, I figure do it right. Hope you're well & Living da Dream

Gazmn · Post by **Gazmn** » Fri Jul 06, 2018 8:05 am

BtB, I'm in the process of adding a bow trolling motor, 36V & have a 48V backup. I've had an epiphany of Late: Solar & Electric : Free & will pay for itself in the long run. I got two kick ass electric scooters for easing down the road, after parking car, or off of boat cruising transport. & while working out this trolling motor thing it hit me. Roger mentioned "The wind is free"... - So is the sun

I'm a convert & preaching the solar/electric gospel. I currently have 300Ws hanging off the back in an array I made, I'm gonna put another 2-400W folding on my bimini. My daily Car is next for me, I'm due. I'll keep the Tahoe to pull Miss Ollie, but looking at the Pacifica Hybrid or Chevy Volt for day to day- Anything that will entitle me to my HOV lanes solo; Or for me, gig to gig