New to Solar from the Philippines, question on combining batteries with different Ah

[tonygcan]

Greetings to everyone. My name is Tony and I just recently completed my solar power project on my farm in the Philippines.
My system consists of 4 x 60 watt, 12 volt PV panels( connected in series to make 48 volts ), 1 Air X, 400 watt peak 48 volt wind turbine, 1 charge controller, 1-2000 watt inverter.

My requirements are 300 watts lights running for 12 hours - 3600 watt hours
1 unit inverter refrigerator 150 watts running for 24 hours - 3,600 watt hours for a total of 7,200 watt hours.

My system comes up short.

I am thinking of importing 8 pcs trojan-l16re-b-370-ah-6-volt-deep-cycle-battery to add to my battery bank.

My question is: can I series the 8 Trojan batteries to make 48 volts and combine in parallel to my existing (4-12volt batteries in series) 48 volt system that has a rating of 100 Ah C/20?

Thank you in advance for the help.

[Sunking]

Tony and welcome to the forum.

I will try to help you out, but you are not going to like what we have to say, but you need to know.

You are compounding your problems by adding another problem and not addressing your main issue, you rsystem is way undersized. You only have about 10% or less of what you need to generate and use 7200 watt hours.

The wind Turbine was a complete waste of money and does not really generate enough power to make a dent in your energy production. Here is the problem. You want to use 7200 wh per day. That means you need to generate at a minimum of 7200 x 1.5 = 10,800 wh per day, more like 14,000 is ideal. Your 240 watt panel system at best can only generate 1400 wh in the peak summer months and only 700 watt hours in the winter months. You are not even close to 10 Kwh you need to generate in a day. At a minimum you need 4000 watt solar panel system. You only have 240 watts.

Move onto the batteries. Even more bad news here. Right now you run 48 volts @ 100 AH right? Problem here is you need 48 volt @ 750 AH. Again you are not even close. My advice is sell the batteries you have, and forget Trojan as they are not a good battery for RE.

You have some hard decisions to make, because it is going to cost you a fortune to do what you want.

[tonygcan]

Inadequate installation

Hi Dereck,
Thank you for the quick reply. And thank you for the reality check.

I thought as much as we were installing the system. I asked my integrator hard questions but could never really get a straight answer. So, I was in a state of denial.

Anyway, originally, I only meant for the solar system to carry my perimeter lights. About 20 lampposts with 9 watt cfl bulbs. It was the integrator who gave me the idea that the system could also carry the inverter ref.

May I ask what would be the right system for a daily requirement of 2160 watt hours. I guess I can go back to my original plan of just supplying power to my perimeter lights for 12 hours a day.

My area is windy about 60% of the year and so I'm hoping that the turbine will be able to contribute to charging the batteries.

I understand that I may need to install additional PV panels to attain my goal.

Being in the Philippines, we don't have most of the equipment necessary for solar installations so I will need to import batteries and charge controllers and inverters from the US.

Also, I'd like to repeat my question, would it be possible to combine same voltage battered with different Ah ratings?

Many thanks!

[Mike90250]

Also, I'd like to repeat my question, would it be possible to combine same voltage battered with different Ah ratings?

Many thanks!

generally, not a good idea. With different batteries, the weaker ones, will degrade much faster, the stronger ones will then not be having the load shared as intended, and they will spiral down the drain shortly following the weak ones. Batteries should be bought in matched lots. Maybe golf cart batteries (any golf courses around you?) would be better when this bank fails. If you can get lower voltage (4V) higher amperage batteries, and run them in series, it's better than trying to get banks in parallel to work evenly.

Here's a great article about connecting batteries in parallel (on the diagonal)
http://www.smartgauge.co.uk/batt_con.html (connect batteries on diagonal )

and some other battery stuff:

http://www.windsun.com/Batteries/Battery_FAQ.htm (short & sweet)
http://www.batteryfaq.org/ (very large)

Generally, much easier to manage 2, 6V in series, than 2, 12V in parallel. Same wattage.

[john p]

Tony I also live a lot of time in Phills. You are going to find importing batteries into Phils is very expensive. As you are well aware batteries are very heavy and cant be easily sent by air. so have to be shipped by sea. I dont know if you have ever experienced it but getting them through customs is a long process and if you have not paid the right people can cost a lot of duty as much as 50% of the cost of the batteries. I had to pay p20,000 duty on 3x 80w panels.
your fridge estimate is out a lot . it consumes 150 w but its not going to run 24 hrs a day it should run no more than 12 hrs a day.
Your expendature is way over the top for a farm.. Dont know what you are farming but it hard to believe the profit margin is very high . And I cant see it ever covering the outlay..I know grid power is vey expensive there but its still far far lower than doint it yourself.
Your AIR X willl not give much power especially with the blades it came with.. There are no really good constant wind places in Phils.. usually very gusty from many directions.
Yoy were given winter sun hours as half summer sun hours Im sure you already know that is not correct.. winter and summer hours close enough to be identical. I dont know your exact location,but that hold true unless you are in far north of Luzon.. your yearly sun hours will be about 5hrs a day.
I will try help you if I can with my experiences if you want.

[tonygcan]

Thank you John and mike for your replies.

Then I guess buying new batteries for a totally new storage bank is the way to go. I was thinking of 6 volt Trojans but have been dissuaded. I wonder what is a reputable brand.

My farm is more of a weekend getaway and it's located in Tagaytay. I actually breed German Shepherd Dogs, www.sinaikennels.com . My solar installation has only been up for about a week now and so still needs major tweaking as I learn by experience what it's actually capable of.

I'd be happy if the batteries could supply enough power to keep my lights (total of about 200 watts) burning for 12 hours.

In a way I realize that the cost of the solar project will not justify the savings but I'd like to do it as a way of helping out the environment.

Thanks everyone.

[russ]

Hi Tony,

Welcome to Solar Panel Talk!

Looks like the guys are starting down the right road.

Russ

[tonygcan]

Thanks

Thanks for the welcome.

I have now revised my system to include only my perimeter lights. At this point about 175 watts for 12 hours or 2100 watt hours. I'll test it tomorrow and hopefully I can go the full night without the inverter shutting off.

[russ]

Let us know your progress please.

Good luck,
Russ

[tonygcan]

12 hours

After bringing down my requirements to 175 watts I was able to go 2 nights (12 hours each night) without the inverter shutting off. Last night however the inverter shut off at 2 am. I surmise that the batteries were not able to get their full charge the day before. I will try to find some LED bulbs to replace some of the CFL bulbs I have installed to further bring down my power requirements.

[john p]

Tony 1W MR16 type leds 12v are very effective as security /perrimeter lights.. Its what we use in Phils just mount them as high as you can and then angle that about 45 deg from horizontal that way you will be supprised just how much spread they have.. A 1W Led 12v draws about 4W. CREE brand ones have very long life and seem to be very reliable.

[tonygcan]

LED lights

Thanks John, that would mean I would disconnect my inverter, rewire my system to work on 12 volts. I guess I could do that since I'm dedicating my solar power for the perimeter lights. Can you buy the LED lights at any hardware?

[john p]

unfortunately NO I brought mine from Australia .Bought them from Jaycar a well known electronics parts chain of stores. It hard to get any decent electronic devices in Phils and if you can no warranty and overpriced
mine are on every night (11 hours)for over 3 years all still perfect same output as when new
Not using the inverter saves power . and as they only 1W you only need wire about #12 and can run at least 30m on any one string

[axis11]

[QUOTE=tonygcan;19246]Thank you John and mike for your replies.

Then I guess buying new batteries for a totally new storage bank is the way to go. I was thinking of 6 volt Trojans but have been dissuaded. I wonder what is a reputable brand.

My farm is more of a weekend getaway and it's located in Tagaytay. I actually breed German Shepherd Dogs, www.sinaikennels.com . My solar installation has only been up for about a week now and so still needs major tweaking as I learn by experience what it's actually capable of.

Ive been in your area a couple of times and I would say you have a good wind. Just make a few modifications on the blades to increase your harvest.

For batteries, try inquiring on motolite's line of industrial batteries

http://motolite.com/battery.php?id=14

My next target for my battery replacements are the stationary batteries, 36 months warranty, 5 and 4mm plate thickness.

For you, I would first solve the charging issues before changing or adding the batteries. Otherwise you just end up with more dead batteries. BTW, dont wait for your inverter to shut-off to know the battery is low. Put a meter to know the SOC of the batt. Your batteries wont last if you keep draining them low.