Home in Haiti with battery backup power questions

Welcome to the forum DarkstormNH!

DarkstormNH wrote: »

To All

Please do not shoot me not just yet, I have been reading this fantastic forums and all the great advice

I have put your post in its own thread... It will make it easier to follow your Q&A's if they are not mixed up with other discussions.

From the friends on it my issue I currently powering my parents’ house in Haiti using a 12 volts magnum
With 8 6 volts Trojan batteries, all wired for 12 volts series parallel
The issue we use to get grid power every night now sometimes we lost power for up to 4 days.
I’m planning on upgrading straight to a 48 volts magnum pae model, and wire my 8 batteries for 48 volts
In series one string, I saw the web site a few sent people to review, their setup look great however it only showed 4 batteries connection I have 8.

If I understand you correctly... You are doing fine. Many people use 12 volt batteries in their systems so 4x12v would give a 48 volt battery bank.

Because you are using 6 volt batteries (many times, a better choice), your 8x6volt = 48 volt battery bus.

I was also planning to purchase solar panel starting with 4 and add to it as you good folks would suggest

Unfortunately, details matter here. We need to know the Vmp and Imp (voltage and current maximum power) for the panels you want to use, and the type/brand/model of solar charge controller too (PWM, or MPPT, etc.).

This can get confusing very quickly--So if you give us the panels+controller(s) you want to use, we can show you how to connect them correctly for your 48 volt battery bank.

You are correct too, in general, you would need to add panels in groups of 4 in series (for Vmp~18 volt panels)--Although, if you use a MPPT type charge controller, you can add other panels (Vmp not 18 volts but ~30 volts for example). In general, MPPT controller cost more than PWM controllers. And Vmp~30 volt panels cost less ($$$/Watt) than Vmp~18 volt panels.

So, doing a couple paper designs (and costings) before you purchase any hardware can save you lots of money and frustration.

So please without shooting me please advise
I’m sure of the following 48 volts for future growth, and no clue how many solar panel I would need to
Safely charge my batteries every day, as to the load I have 700 watts microwave that we used 30 minutes per day
A 55 inch lcd tv five hours per day, and a 32 lcd 2 hours per day, 12 cfl light bulbs 7 watts each
A few 2-3 cell phone charges and cable box

We do not shoot people here with questions--It would get very quiet very quickly if we did. Also, we want to make sure you don't electrocute yourself either.

In general, it is critical to measure and understand your loads. A too small system will not power your needs. A too large system is expensive and a waste of money.

If you can purchase a Kill-a-Watt type meter to measure your daily loads--That will answer about 90% of our questions. Also, knowing (roughly) where the home is, we can estimate how much sun you get too.

The standard North America Kill-a-Watt meter is for 120 VAC circuits... If you have 240 VAC appliances, those will need another meter setup for 240 VAC.

Note that off grid/backup power is not cheap... Sometimes you are better off running the smaller loads from the battery system and converting larger loads (such as cooking appliances) to propane or other fuels. Also the newer LED LCD type TVs can use much less power than even those from a few years ago--Conservation is usually worth the money (it is usually cheaper to conserve power than to generate power).

Also, I notice you don't have a refrigerator listed--Do you need to power one of those too? Typically, adding a refrigerator moves you from a "small" to a medium size off grid power system--And if you add solar panels, this can make for a "not cheap" system.

If the multi day power failures are not too often--Frequently an AC Generator may be more cost effective than a full off grid solar power system. Run the solar for your smaller loads (lights, TV), and run the genset for larger loads (microwave, cooking, refrigerator for 12 hours per day, etc) when needed.

-Bill

Once we