Question from the Philippines

[islaburi]

Hi Folks, glad to know such a forum exists for people to post questions and get expert answers anything solar. I’m from the central Philippines and you would not believe how high power rates here are. I live in an island but there’s grid power because there’s a causeway connecting us to the mainland.
Frequent blackouts is a norm here. An average of 2-3 times a week and for several hours each time. When a storm passes anywhere in the region, no power for a week or two.
Tried several solar companies here and the quotes are very high. I looked at buying direct from China since most solar companies here source their supply there. After a few months of reading/asking/googling/youtube/blogs etc. I have decided to go with a hybrid wind and solar setup considering I’m on a hill in the island and it can be windy here 3 days in a week average.

My setup is 96 volts system.
3 strings panels paralleled:
watts - 200w rated max power (12 pcs.)
tolerance : +/- 3%
vmp - 36.0v
current at pmax (imp) - 5.56a
voc - 44.2v

Charge Controller 96V 3kw Solar and 2kw Wind with dumpload: http://demingpower.en.alibaba.com/pr..._load_5KW.html

8 pcs. 150AH in series of these Batteries - http://www.motolite.com/products/sol...ycle-batteries

2kw Wind Turbine: http://www.alibaba.com/product-detai...38.35.1.XH9INV

This inverter has Grid bypass and does not have charging function: http://panpower.en.alibaba.com/produ...ar_System.html

This is my issue. First time I switched to the batteries from the grid (2 weeks ago), the brand new delivered batteries lasted before inverter switched to grid for 16 hours with an average of 1kw/hr load. Since then, this is the daily scenario:

The panels would start charging batteries as early as 6:30 a.m. 400-450 watts
By 9 to 11 a.m. controller would show 1-1.2KW charging rate
By 11am -2 pm controller would show 2-2.2 sometimes 2.4KW charging rate
Past 2 p.m. to 4 p.m. charging rate would be back to 700-900 watts
After 4 p.m. it would be back down to 350-400.

Before 11 a.m.most of the time, the controller starts dumping load. Batteries voltage would reach 114V and inverter indicates 100% battery charge. At this point, inverter auto switches to battery. My load from 11 a.m. to 3 p.m. would be 1.5kw/hr. From 3 p.m. to 8 p.m. is 1kw/hr. By 7 p.m., my 1,200AH battery bank fully charged at 11 a.m. will be down to 20% as per display on Inverter LCD and 94V on charge controller and inverter would auto switch to grid.
It would stay on grid till around 11 a.m. next day. This is the daily scenario except for 4 days where strong, continuous southwest monsoon winds was giving me 1.5-2kw power almost round the clock.

My biggest question is, the brand new batteries delivered and connected the first day I switched to this system had a run time of 16 hours on a similar load. While the same battery bank charged (as indicated by inverter switching to Battery and controller showing 114V and dumping load) by solar and wind power has a run time of only 7-8 hours????

Would greatly appreciate your opinions and advises. Thank you for taking the time to read this.

[inetdog]

It looks like your batteries are Flooded Lead Acid, a good conservative choice for your application. But you are seriously abusing your batteries and need to take steps immediately to keep them from being permanently damaged.

1. Get a temperature compensated hydrometer to measure the specific gravity. For a start check one cell on each battery. Do not trust voltage measurements or charger SOC indicator when determining the State Of Charge of your battery bank.
2. The low voltage cutoff on most if not all inverters is set to protect the inverter, not the batteries. You are discharging your batteries far too low for good cycle life.
If your capacity is 150AH then a typical day's use in daily cycling should draw no more than 30AH from the bank. In case of a power failure you could draw down as much as 75AH as long as you are able to recharge the batteries in the next day or two at most.
3. After looking at the SG, you will probably find that the batteries are not fully charged. In general a solar PV source cannot put back more than 20% capacity in one day. The first several hours of Bulk charging may get you up to about 80% SOC, but you will need an Absorb and Float of as much as 8 hours to get all the way to 100% charge. You cannot get that from PV alone when you have discharged the batteries that low. Hook up an AC charger for at least 10 hours to see if you can recover the capacity of your batteries. If you cannot access a 96V AC-source charger, just let the PV charge your batteries for at least 4 days without putting any load on the batteries at all. See if the SG improves. If it does not, you have destroyed your batteries already.
4. Based on your stated power needs, your battery bank is about a factor of 4 too small.

[islaburi]

Oh-o...I hope it'snot that bad. I don't have a hydrometer and would try to purchase one asap. Also don't have a 96V AC charger. I only have a 12 Volt 20A AC charger. I will let the batteries be charged for the next four days and pray for it's recovery. Will update you what happens next. Thank you very much for your time on this.

I have understood everything except this:

4. Based on your stated power needs, your battery bank is about a factor of 4 too small.

Could you please explain further. Thank you again.

[Naptown]

You do not have a 1200 amp hour battery bank.
You have a 150 amp hour battery bank

First thing is check the water levels in the batteries. At some of the charge rates you had you may have boiled the electrolyte out of them.
That battery bank likes to be charged at about a 15 amp rate but between 12 and 18 are fine. You recorded some very high charge rated.

[Living Large]

Oh-o...I hope it'snot that bad. I don't have a hydrometer and would try to purchase one asap. Also don't have a 96V AC charger. I only have a 12 Volt 20A AC charger. I will let the batteries be charged for the next four days and pray for it's recovery. Will update you what happens next. Thank you very much for your time on this.

I have understood everything except this:

4. Based on your stated power needs, your battery bank is about a factor of 4 too small.

Could you please explain further. Thank you again.

If you use 16 kWh per day, for example, your batteries should be about 80kWh so that you use 20% per day when cloudy. Your bank is 96V @ 150Ah, or14,400 Wh = 14.4 kWh

A key thing to note that someone else pointed out is your batteries in series means the capacity stays the same as the voltage increases. Paralleling batteries increases the capacity. Two 12V 150Ah batteries in parallel is 12V @ 300 Ah, two in series is 24V @ 150Ah.

[Living Large]

If you use 16 kWh per day, for example, your batteries should be about 80kWh so that you use 20% per day when cloudy. Your bank is 96V @ 150Ah, or14,400 Wh = 14.4 kWh

A key thing to note that someone else pointed out is your batteries in series means the capacity stays the same as the voltage increases. Paralleling batteries increases the capacity. Two 12V 150Ah batteries in parallel is 12V @ 300 Ah, two in series is 24V @ 150Ah.

I still can't edit on this site, and wanted to clarify that putting identical batteries in series keeps the Ah capacity the same as the voltage increases.

[islaburi]

You do not have a 1200 amp hour battery bank.
You have a 150 amp hour battery bank

First thing is check the water levels in the batteries. At some of the charge rates you had you may have boiled the electrolyte out of them.
That battery bank likes to be charged at about a 15 amp rate but between 12 and 18 are fine. You recorded some very high charge rated.

Your right. I forgot it's on series. The water levels are about half an inch from the bottom of the vent well. The amp rate range is about correct. Thank you sir.

[islaburi]

If you use 16 kWh per day, for example, your batteries should be about 80kWh so that you use 20% per day when cloudy. Your bank is 96V @ 150Ah, or14,400 Wh = 14.4 kWh

A key thing to note that someone else pointed out is your batteries in series means the capacity stays the same as the voltage increases. Paralleling batteries increases the capacity. Two 12V 150Ah batteries in parallel is 12V @ 300 Ah, two in series is 24V @ 150Ah.

Gee, i'm 24 batteries way from the ideal bank. Thanks for pointing it out.

[SunEagle]

I still can't edit on this site, and wanted to clarify that putting identical batteries in series keeps the Ah capacity the same as the voltage increases.

When editing instead of clicking on the "save" button put your cursor in the reason for edit block and hit enter. That should work.

[Living Large]

When editing instead of clicking on the "save" button put your cursor in the reason for edit block and hit enter. That should work.

Thanks for this tip. This will encourage me to state a reason I usually don't, and it used to let me submit my changes. I'll give it a tri editing this.

[Living Large]

Thanks for this tip. This will encourage me to state a reason I usually don't, and it used to let me submit my changes. I'll give it a tri editing this.

Nope - didn't work. At least not when I entered a reason in the box and clicked "Save"

[SunEagle]

Nope - didn't work. At least not when I entered a reason in the box and clicked "Save"

Clicking "save" doesn't work. You have to put something in the "reason box" then while your mouse cursor is in that box just hit "enter".

[Living Large]

Clicking "save" doesn't work. You have to put something in the "reason box" then while your mouse cursor is in that box just hit "enter".

Perhaps if I had read more clearly I would have understood what you wrote

{edit} Let's see if it works.

[Living Large]

Cool. Thanks for the tip.

[GsGoodwill]

Question from the Philippines

Hello Mitchell Just wanna say, I love Philippines and the Filipinos