Solar newb: choosing MPPT?

[john61ct]

Xantrex makes good product

but has HORRIBLE after sales attitude, once warranty is up they expect you to toss it and buy new

Even their authorized repair shops can't get parts

[Iceni John]

Originally Posted by john61ct

Xantrex makes good product

but has HORRIBLE after sales attitude, once warranty is up they expect you to toss it and buy new

Even their authorized repair shops can't get parts

Magnum's inverters are made in the USA, are field-serviceable, and one can buy factory-refurbished Magnums for way less than brand-new. I bought my refurb Magnum MS2000 for less than $1000, and it's probably better than most brand-new inverters. Moral of the story: don't buy cheap Chinese crap, and try to not buy anything from Amazon!

John

[john61ct]

well, maybe better to say, there are product categories where the good stuff is not available there

[Simplicity]

I'm late to the game with this post, yet here's what I did and why.

1) I was fortunate enough to meet Ross and he was more than generous with his knowledge and reasoning.

2) My bus name is Simplicity for a reason, I wanted things simple...well, as simple as can be.

3) My build buddy and Ross have the same philosophy, which I've adopted, which is to go with what's easy to replace in a pinch and have redundancy.

4) Overbuild and over protect and under-use.

For me this meant the following electrical setup:

30a shore / gen power using a 4500/3700w Westinghouse inverter generator. Highly recommended from my short but very positive experience.

4 - 6v 225ah AGM batteries in series/parallel.

Samlex NXT 3000w Inverter

PowerMax MP3 120v 100A Multistage battery charger

4 - 225w 37v (used, puts out over 30v) poly 60 cell panels

EpEver 150v/100a smart charge controller

My 12v loads include:
Minimal LED lights
12v/120v Whytner 5cuft chest freezer (run it at 38 degrees)
Fan on 19K BTU propane heater
Water pump

My 120v loads include:
9k BTU A/C / Heat pump Pioneer Mini-split
Instant Pot
12v/120v Whytner (same as above)

I have not yet installed my solar panels or charger. I've only used the bus once and the generator kept everything going and charged. Once I add the solar, I'll barely use the generator.

I would estimate I over built everything by a good 25% and plan to under-use it by 50%. Why? Because for those times I need to use it at close to 80%, I can do it easily. I'm not pushing any of my equipment hard, so in theory, it should work well even over time. Baring any manufacturer issues, I think the system will serve the bus for a long long time. In addition, if I do want to add more load, I have the ability to do it with the current system.

Hope that helps someone.

[Buster Junior]

Hi there. I, too, am struggling with figuring all of this out. I am currently sifting through volumes of info and just when i think i am getting a grip, i suddenly get overwhelmed. I definitely feel like the dunce in the class. I have found a site called " explorist life" very helpful. Wish I could be of more help. Good luck!

[IC08]

Originally Posted by Buster Junior

Hi there. I, too, am struggling with figuring all of this out. I am currently sifting through volumes of info and just when i think i am getting a grip, i suddenly get overwhelmed. I definitely feel like the dunce in the class. I have found a site called " explorist life" very helpful. Wish I could be of more help. Good luck!

I know how you feel! I finally decided on a set up and will hopefully be getting it running for testing within a few weeks, I'll be back to report how well it worked out and "collect the arrows in my back" as they say.

I'll check out that website thanks for the info, and good luck to you as well!

[mymincave]

Will Prowse in his excellent book “Mobile Solar Power Made Easy” suggest to get the biggest MPPT you can afford. I’ve got 1250 watts of panels with a 3000 MPPT and that will allow me to expand to more panels when I can afford them…

[IC08]

Originally Posted by mymincave

Will Prowse in his excellent book “Mobile Solar Power Made Easy” suggest to get the biggest MPPT you can afford. I’ve got 1250 watts of panels with a 3000 MPPT and that will allow me to expand to more panels when I can afford them…

I'm thinking my plan is to go with an "all-in-one" to get me moved in, and I will gradually replace stuff as I can afford it. First thing to go in will be a few victron MPPTs -and all the expensive doo-dads to go with it for monitoring. Maybe even add a whole extra system just for entertainment/tools and put the panels in the yard since I will be stationary most of the time anyways.

I already got a victron DC/DC and that shiny blue finish has got me hooked, but man is it costly!

[john61ct]

Originally Posted by mymincave

Will Prowse in his excellent book “Mobile Solar Power Made Easy” suggest to get the biggest MPPT you can afford. I’ve got 1250 watts of panels with a 3000 MPPT and that will allow me to expand to more panels when I can afford them…

No, with Victron's revolutionary scaling/pricing you are best off with multiple smaller units, even 1:1 ratio. Buy the panels you find good deals on, matched to the right SC.

Later can add completely different ones, no need to buy exactly matching.

Save lots of money, plenty of flexibility, much more efficient conversion, gain redundancy when something breaks, and optimise shade handling.

[Rock-N-Ruth]

Originally Posted by IC08

Hey all, in the process of finalizing my solar setup. Right now I'm focused on the panels/MPPT/battery bank as it seems to be the biggest chunk of the whole setup.

I'm leaning towards 8 x 250 watt - 10 amp - 24v panels =2000watts

and 4 to 6 of the 100ah "Ampere Time" batteries in a 24v bank

Can anyone recommend an MPPT that would fit nicely? I've read everything i can find but I just get more lost as I go, I'm leaning towards the Victron 150/70 based on the math I have so far but it doesn't seem right. 2000 might also be "too much" solar but its really cheap for what I found

I'm told that to find amps for MPPT you divide 2000watts by 28.8 (for 24v) and I get 69 amps. I really can't find anything about whether the panels in series or parallel would help the situation.

Look at how many watts your controller can handle from your solar array at 24V. You will probably find you will need to arrange your pv arrays into two 1000w arrays and use two controllers to get the maximum out of your panels potential.

Ruth and I have 12 327W Sunpower Panels. They are arranged in groups of 4P. Three MrPwr mppt 60A controllers each handle up to 1600W at 24V.
We chose the MrPwr controllers because they were cheap, intending to go with more expensive name brand controllers later. That was two years an megawatts of solar power ago.

The MrPwr controller at about 120 bucks, configures to your lfp batteries. In conjunction with your batteries BMS, they will efficiently, and safely maintain your batteries.

You may ask why we have such a large solar array. The answer is simple. Comfort. We have a huge, 13-15KW battery for the same reason. We like to be cool when it is hot and warm when it is cold. We love to be able to shop for food once a month.
The sun tops off our batteries before noon most days and then just powers our comfort till the sun goes down. At which point our large bank of BYDs takes over.

Oversized is the prize.

[Rock-N-Ruth]

Originally Posted by IC08

Hey all, in the process of finalizing my solar setup. Right now I'm focused on the panels/MPPT/battery bank as it seems to be the biggest chunk of the whole setup.

I'm leaning towards 8 x 250 watt - 10 amp - 24v panels =2000watts

and 4 to 6 of the 100ah "Ampere Time" batteries in a 24v bank

Can anyone recommend an MPPT that would fit nicely? I've read everything i can find but I just get more lost as I go, I'm leaning towards the Victron 150/70 based on the math I have so far but it doesn't seem right. 2000 might also be "too much" solar but its really cheap for what I found

I'm told that to find amps for MPPT you divide 2000watts by 28.8 (for 24v) and I get 69 amps. I really can't find anything about whether the panels in series or parallel would help the situation.

Look at how many watts your controller can handle from your solar array at 24V. You will probably find you will need to arrange your pv arrays into two 1000w arrays and use two controllers to get the maximum out of your panels potential.

Ruth and I have 12 327W Sunpower Panels. They are arranged in groups of 4P. Three MrPwr mppt 60A controllers each handle up to 1600W at 24V.
We chose the MrPwr controllers because they were cheap, intending to go with more expensive name brand controllers later. That was two years an megawatts of solar power ago.

The MrPwr controller at about 120 bucks, configures to your lfp batteries. In conjunction with your batteries BMS, they will efficiently, and safely maintain your batteries.

You may ask why we have such a large solar array. The answer is simple. Comfort. We have a huge, 13-15KW battery for the same reason. We like to be cool when it is hot and warm when it is cold. We love to be able to shop for food once a month.
The sun tops off our batteries before noon most days and then just powers our comfort till the sun goes down. At which point our large bank of BYDs takes over.

Oversized is the prize.