help me out im goin solar

[fabricator john]

hey yall ,im john from va. what i have is a bayliner 2670 explorer,cuddy cabin/trawler, it has a few ammeneties and we usually spend late fri till sunday on the boat as its 1 1/2 hr from home ,i have a honda but dont like useing it if i dont have to.My good friend hooked me up with a Kyocera kc85ts panel,and im pretty shure i want a mppt controller,i would like to be able to add a second panel later,i have one batt on the "house" bank but i would like to make it three,the panel is all i have so far and i hate the idea of doing it twice,so please make some suggestions to steer me in the right direction,
thank you for any imput you could lend
john...2670 explorer"IPLANEMA"

[Pblais]

John,

It's time to do some math homework. Sorry, but its a requirement. You need to compute the amp hours you use against what you can make. Normally trawlers motor as they move and so can handle large alternators to recharge for the extended anchorages a cruising trawler is apt to make. Solar power is not really cheap but it is quiet. It's the real reason to do it. I don't recall ever anchoring in the shade - at least often. So, how much power do you use? have you considered a battery monitor? Do you have a genset too?

You do need regulation or the over voltage at high noon starts to eat away at the batteries and they are expensive. You really can do the math and make the money work.

[fabricator john]

paul ,im on lake anna (i see you are from va also)(small world) we generally spend the weekend on the hook,we boated from end of march till firs weekend of november,i burned 2 tanks all year,going almost every weeked! the boat stays at the slip all week and we stay over the weekends out on the islands,id like to have enough batt to run a/c sat night without the generator ,but im not shure on the math plus a true sine inverter is pricey in a hurry,unless i coud get one small enough or on the money math wise,how much could i get charged in 5 days between weekends?
thnks john...2670 explorer.."IPANEMA"

[Pblais]

id like to have enough batt to run a/c sat night without the generator

You can't get there from here.

The amp hours are too large for the battery bank to not be dead in an hour or two or the size of the bank so large you could not recharge it without a 30 amp power cord. The goal is to have thre fridge still cold and be able to run the lights too for 24 hours. A/C with out external power just can't be done except in November. In the summer the water is so warm you just don't stand a chance. Micorwaves are just as bad, but you may be able to use a little in the morning and be OK.

The solar is still a great idea for hanging around on the hook though. I use it here and I really have not been plugged into shore power with the charger on in about a year. Being plugged in makes you available for inducted currents from the shore power. Dominion still hands out spikes regualrly.

We don't live aboard but the solar keeps the batteries topped off after all trips and adds to it when we don't travel. We motor enough to keep the batteries going on trips of a week or more.

If you get down here to the fat end of the Bay give a yell.

[fabricator john]

Does anybody make a reasonable mppt controller/sine inverter combo unit because i'll need both anyways,or am i dreaming?
john,....2670 explorer..."IPANEMA"

[Pblais]

No one has combined all you ask in one box. The controller regulates the current going in to not exceed the acceptance rate of the battery bank based on charge level of the batteries, temperature and the output of the panels. The inverter draws Dc amps and converts them to AC amps. They don't get connected because they don't have to be. The idea is you won't draw more out than you put in else the bank goes dead. You really don't need an integrated solution since one is the input and the other is the output. The ability to set up a solar array that can all on it's own power a boat is really only limited to how much power you take out.

Have you computed the DC amp hours you need to do all the fun stuff you want to do? Can you add it all up for a typical day? You need to look at both sides. To make this work you really need to minimize the output side. Solar is not forgiving when it comes to high peak loads. To make this work you really do want to minimize the power you ask for first. Solar is not that cheap and it does not make a large amount of amps given the size of a typical boat. You won't be arc welding.

[fabricator john]

so in central virginia how many amp hours can i create(as in store in batteries)in 5 days with a kc85 panel and a mppt charger? i have the panel allready and i think i'll make my plan working backwards,as in batteries first and then figure toy's,how much juice should i be able to create /store wile the boat is parked during the week?
john 2670 explorer "IPANEMA"

[camaraderie]

In 5 days of sunshine you may be able to get 125-150AH's back into your batteries which would suggest you have a bank of 3 group 27's or 31's since you never want to go BELOW 50% of "full" and 150ah's would be 50% of 300 ah's.
For what it is worth...150 ah's should be enough to run a small fridge box for 2 days OR a car Stereo and a couple of lights for 15 hours.
Download the xls spreadsheet from here for a list of typical amp usage of various boat equipment.... Southeast Marine Services :: Technical Information :: Battery Bank Sizing

[fabricator john]

sweet that's what i was hoping for, somewhere i was reading that some mppt controllers make make rf noise? for three group 31s i would want enough controller ,and that i could add a second 85watt panel later,maybe 20 or 25 amps?any suggestions? also who has a reasonably priced true sine wave inverter in the 1500 to 1800 watt range, i have a little window type a/c that i run on my honda its only 5000btu the spec sheet says it draws 5 amps which may be true the honda on economy mode never comes far off of idle.in buying the devices i want to only do it once , i'll happily trade fab or tig work for parts,im on a shoestring,but i'm real good with s/s,i'll probbably need a batt monitor of some sort too? I know you guys can keep me on the right track and I really appreciate any advice given..
john...2670 explorer..."IPANEMA"

[Paul Elliott]

Originally Posted by fabricator john

sweet that's what i was hoping for, somewhere i was reading that some mppt controllers make make rf noise?

They can make noise, but by putting ferrite clamps around the wires in and out of the controllers you will significantly reduce the radiated noise. I haven't noticed any noise on the SSB channels I have used, but there could be noise elsewhere.

for three group 31s i would want enough controller ,and that i could add a second 85watt panel later,maybe 20 or 25 amps?any suggestions?

An 85W panel will put out no more than 7A at 12V. My BlueSky SolarBoost 2000E (a very popular MPPT controller) is rated to 25A, so it should handle three 85W panels. I have three 100W panels on mine.

also who has a reasonably priced true sine wave inverter in the 1500 to 1800 watt range, i have a little window type a/c that i run on my honda its only 5000btu the spec sheet says it draws 5 amps which may be true the honda on economy mode never comes far off of idle.

Note that 5A at 120VAC will translate to at least 50A at 12V from the batteries into the inverter, and probably closer to 60A. An 85W solar panel will deliver perhaps 28 Amp-Hours over a 24-hour day. This means that the single 85W panel will provide enough power to drive your A/C for at most 1/2 hour per day.

A Group 31 battery has about 120 Ah capacity, so the three batteries will run your A/C about three hours (from 100% charged down to 50% charged). It would then take over six days for your 85W panel to recharge the battery.

I'm being generous with the efficiencies here -- the performance will likely be significantly worse. Even if you get the three solar panels, your charging capacity only runs the A/C for 1-1/2 hr a day, and this is ignoring any other loads you will probably have.

I hope this illustrates why the replies have been of the "you can't get there from here" type. Solar panels alone are just not going to support extended operation of heavy loads such as A/C. You just can't fit enough on a typical boat.

(Can someone check my math? I'm pretty sure it's OK, but I have been known to occasionally slip a decimal point.)

[fabricator john]

thank you for the information paul,i know its a journey figureinthrough this solar thing,my needs are really gonna be helped in the charge times and how much i can create and store,heres the thing,im land locked on a big boat on a little lake,my boat is on lake anna in central va. its an hour and a half from home we spend weekends on the boat so,the panel is unobstructed and at the slip from sunday after noon till friday night late,5 1/2 days parked,charging batteries,when im out we usually dont go too far and spend the weekend on the hook or beached on one of the islands,i dont use the fridge because it just draws too much,the only thing the panel should run when im parked is the stereo and or tv (GOT KIDS) my idea was to save the bank for a/c and dont use/listen to the generator,sat nite only,is what im wanting/dreaming about,, help me figure how..
john ...2670 explorer.."IPANEMA"

[Pblais]

my idea was to save the bank for a/c and don't use/listen to the generator,sat nite only,is what im wanting/dreaming about,, help me figure how..

I really think you could do this with a panel and run the fridge when you are there and shut it off when you leave. It should charge back during the week. That gives you lights, a little stereo, and fridge for the bulk of the weekend. If you go more than a day and a half you'll need a shore power connection for a night to make the fridge go all weekend.

Plug the boat in at the dock the night you get there Friday and turn on the fridge. Now when you leave in the morning Saturday the fridge is cold and the batteries loaded. You should be good to go till Sunday night. The panels work all week and you don't really have that much to put back.

The A/C - forget about it. You can't make the starting current to flop it over let alone run it. If you multiply the rated amps by 120 volts that would be AC Amp hours required to run it. Now multiple that by 10 to convert it to amp hours using 12 volt DC. and add 10 percent for the trouble of converting it DC to AC. Now look at the amp hour rating on the batteries. You'll need a little barge to store the battery bank. The cost of this is more than a really long extension cord or maybe a hard wired mooring.

[camaraderie]

What Paul said! Dittos.

[Martinini]

Here are a couple of sites that might be of intrest Power Inverters (All Models), Wireless Remote and Applied Magnets don't let the applied magnet name throw you, they have lot of wind gens and solar items for sale.

[Paul Elliott]

I agree, the air conditioning is the deal-breaker. Weekend use of the refrigerator, stereo, and lights should be easily supported with a reasonable solar panel and battery installation.

Some numbers:
Refrigerator -- I have a Seafrost 12V unit, which seems pretty typical. Mine draws 5 Amps when running. How much time it spends running will depend on the amount of insulation you have, and on the ambient temperature. Let's assume it runs 25% of the time, which is probably close enough. This means that your refrigerator will consume (5A * 6 Hours per day) = 30Ah per day.

Stereo -- Mine draws 0.6A. Lets say you like to crank it up six hours a day; probably 1A drain * six hours = 6Ah per day.

Lights -- My Alpinglow flourescent lights draw 0.73A. Halogens draw about 1A. LEDs will draw perhaps 0.2A. Lets assume that your lights will draw 2A total, and you will use them six hours a day. This is 12Ah per day.

Do you need to run an anchor light? An incandescant bulb draws about 2A, and running it for 10 hours consumes 20Ah. An LED anchor light consumes about 1/10th of that. Let's say you don't need the anchor light, but you see what a big load it can be.

Adding these up, you get (30 + 6 + 12) = 48Ah per day.

Your single 85W panel provides over half of this (about 28 Ah per day). This means that the battery needs to make up the remaining 20Ah. Your single group 31 battery (120 Ah) will provide 20Ah per day for three days before it drops to 50% charge. If the sky is heavily overcast and you get nothing from the panel, then the battery will take just a little over one day to discharge halfway.

If you have two 85W panels and it is never cloudy, the battery never goes dead because the panels provide more power then you need.

Your actual numbers will vary, past performance is no guarantee of future results, etc, etc, but if you forget about the A/C things look pretty good.