I don't presume to be a guru but this is has been my experience. The answer to your question is not a straight forward one.

A few points to consider;

1. All batteries are not made equal(You can't compare a Chinese no name battery to a Fullriver or a Lifeline, or even compare a Rolls Surrette 4000 series to a 5000 series of the same capacity ; what brands of batteries are you considering?

2. What Type of batteries are they and what type of charger do you have? Am assuming they're both Lead Acid, but are they the same type of lead acid batteries? FLA, AGM or GEL?
Most Chinese and Indian inverter chargers won't be able to properly condition L16 FLA batteries because of the high equalization voltages required to properly condition FLA batteries.

3. Do you happen to know the weight of both batteries? For instance; the Trojan L16H 6Volt, 435AH and the L16RE 2Volt, 1110AH weigh the same. That just tells you that they use almost the same weight of Lead in making these batteries. Deep cycle batteries that die a natural death are mostly due to positive grid corrosion-a thicker plate means it will take longer for that to happen. The warranties (7 years for L16RE 2V and 2 Years for the L16H 6V) on these batteries attest to the fact that the 2V battery is made to last longer, this may not be the case with your batteries.

fogechi:
Please what advantage does 2v 500ah batteries have over 12v 200ah ones.

My Two cents!
Both Maximum Power Point Tracking (MPPT) and Pulse Width Modulation (PWM) are the most popular methods used in off grid solar battery charging. The choice to use any of them should be driven by system design and not which one is best.

In both instances-MPPT and PWM, PWM is applied when battery bank is nearing full capacity or set voltage; PWM algorithm slowly regulates the amount of power applied to the batteries by pulsating the amount of power supplied by the panels, preventing the battery voltage to rise above the set voltage (absorb voltage). The MPPT on the other is experienced when batteries are in bulk charging mode. The MPPT algorithm does a DC to DC conversion, which augments the higher voltage from the panels to allow maximum power to be applied to the batteries with a higher amperage than that supplied by the panels. In more advanced charge controllers, the tracking for Maximum power point is an ongoing event in the charger. MPPT performance advantage shines in low irradiance (cloudy days) or hot days when solar panels are not at their best; the charger tracks maximum power points and enables charger to harvest the most from a bad situation for solar panels. PWM just allows the panels to do what they want till battery voltage approaches a set voltage. That is why panel and battery voltages must be close matched; smaller panels like a Kyocera 140D has a Voc of 22.1V, Vmp of 17.7V. This panel on a good, cool sunny day may produce more power if hooked up to a Tristar TS-60 (Self-consumption of < 20mA) than it would, if it is hooked up to a Tristar TS-MPPT 60 (Self-consumption of about 2.7W). But if the clouds start rolling by or it gets really hot, the tables are likely to turn.
Considering the statement below;

…”MPPT's 30% additional yield is the *theoretical* maximum gain when performance is measured under STC - a cold, clear skies sunny day with temperatures around or below 25°C - I am sure such perfect conditions are scarce to come by in real life and these are amongst the reasons why hardcore old-school engineering firms like Bogart Engineering (makers of the Trimetric and other excellent battery monitors) don't make MPPT charge controllers but only PWM.”

The gain is in comparison to a PWM, not under standard test conditions (STC). if we are using a 20V or 24V panel (Canadian Solar CSK6K-275M, Solar World SW345 XL respectively) to charge a 12V battery. You can take advantage of the MPPT's ability to convert a higher panel voltage in a series connection to help charge your batteries in bad weather. A PWM will not be able to deliver under the same conditions.

Your system may be under 1000W, but the panels happen to be 24V panel and you also happen to have a 12V battery; it will be advisable to use an MPPT. If you happen to have a 24V battery bank and also have the Solar World panel mentioned above which has a Voc of 47.8V and Vmp of 38.2V @ STC; a PWM will be appropriate.

If you live in a region with a lot of cloud cover/low irradiation or very hot climatic conditions; PWMs won’t be the best for you. Your panels won’t deliver your batteries to absorb voltage to take advantage of the PWM effect, MPPT will be your friend. If you find yourself in a place where you experience a lot of West African typical February weather and your system isn’t big then by all means choose a PWM.

In conclusion, use what best suites your system. MPPT may be a waste of resources if it is applied in the wrong setup.

"Don't call for a 6.2L diesel engine when you are designing a motor bike"

Take another look at your link.
http://www.pbase.com/mainecruising/solar_controller_testing

US L16HC XC2-6V, 420AH; S.G at 100% battery capacity is 1.270, Bulk/Absorbs at 7.35V, Floats at 6.51V and equalizes at 7.65V

Trojan L16P-6, 420AH; S.G at 100% battery capacity is 1.277, Bulk charge Voltage is 7.41V, Absorbs between 7.05-7.41V, Floats at 6.75V and equalizes at 8.1V.

Both batteries are not bad batteries, the Trojan company has been around longer and that adds to their experience. I.ve used the above US batteries for 5 years; they were under charged, left to dry a number of times and yet they survived 5 years before 2 went bad. This tells me they could have lasted for about 7 to 8 years. I have crown batteries now, but a friend has Trojans. They are just 1.5 years old-so far so good. I have guys on another forum who have used the Trojan batteries for more than 8 years.
It is going to be the little things or not so little things that you should consider; cost, maintenance regimen, availability of batteries, how fresh are the batteries or how long those batteries have been on suppliers shelf etc.

The S.G for Trojan battery is higher than US battery, requiring a higher voltage or longer absorb time to completely reverse the chemistry for a full battery charge. You notice that the float and equalize voltages are higher for the trojan batteries, this means the trojan batteries are prone to consume more water than the US batteries. I will also advice against Trojans if your charging device does not go above 31V for the equalize cycle. Am not against the Trojans, I just hope you to consider all these things before you make up your.

pitodenz:
Between Trojan and US Battery which is better
Pls I need technical n experienced advise
Thanks

Thanks Tivta, you are right, some off gird inverters do not use fans. These are either very small inverters which do not incorporate a charger or are going to be prohibitively expensive. Also most micro inverters and DC optimizers (these are grid tied, not very useful in a blackout scenario) do not use fans. Our load requirements and climatic conditions will necessitate the use of fanned inverters

tivta:


Nice explanation BUT not all inverters use fan for cooling, there buy reducing extra load.

I am sure the digital displays alone will not suffice to help give you a good explanation. Not knowing your Inverter capacity, type of inverter, whether it has it always been like this or this is a recent occurrence? So many factors can be contributing to this issue; size of cables, fans going bad, location of inverter, even the monitoring devices could be contributing. I am just covering all basis I can think of in this situation, since I don't know anything about the setup.

I have attached an efficiency curve for Xantrex XW4548/6048/4024 just to bring clarity to some of the concerns I have raised.

These inverters are all rated above 92%+ efficient, albeit, you notice that when the load is less than 300W, the efficiency suffers drastically; If a big inverter (3000W+) is used for a small load (300W), the efficiency of inverter is not going to 92%

These inverters are from the same manufacturer (Yes Xantrex, now owned by Schneider), the efficiencies vary differently with respect to varying load. The XW4024 commences an efficiency degradation after 1000W, while the others are still doing very well. [b][/b]ALL INVERTERS ARE NOT MADE EQUAL.

Location of an inverter is also key; All inverters use switching devices and AC inductors of some sort. These devices generate a fair amount of heat hence the need for the cooling fans. An inverter located in a functioning kitchen is not going to out perform one that is located in a place with lots of cool breeze. Likewise an inverter that is located in area granting access to the fans to draw in a lot of dust, so that the electrical components are coated with thick layers of dust inhibiting proper cooling.An inverter like this is not going to out perform one that is carefully placed. Big names SMA, Xantrex, Outback etc use filters at the vents for the fans to filter out air.

Cable sizing; For simplification, lets do some basic math; Resistance R to the flow of Electricity is proportional to the Length L of the wire and inversely proportional to the Cross-sectional Area A

R = K (L)/(A), K is resistivity- material dependent. In order to keep resistance low, an appropriate diameter must be chosen to correspond to the length and current that is flowing through the wire. Else part of the power consumed is lost to heat in the wire. This could also potentially damage the wire-for this reason fuses and breakers are sized based on the connected wires (See attached sheet).
Power loss to heat;
P=I[sup][/sup]2R

Monitoring devices; Not all measuring devices do the job with the same degree of accuracy. For solar applications, this may not be an issue at all; the monitoring devices we use may not be accurate by standards in some industries, but they give us the requisite information with a degree of accuracy, satisfactory enough to tell us we are in trouble or not. But, when two different devices (from different manufacturers) are being used to take measurements, the difference in measuring and calibration methods may contribute a little bit for us to be alarmed. You may want to use the same device in taking all your measurements.

Some of the points above are insignificant, but I thought it is worth mentioning if all contributing factors are to be considered.

efuro:
Hello House
My inverter waste much of my precious battery power.

It’s my belief that DC watt is 92% of AC watt and current stays same whether DC or AC.
Can someone help with explanation why my inverter draws so much juice just to produce so little. For instance, it draws 11.60A@307W DC to produce 1.47A@247W AC to power load (of a Deep Freezer, 32” LCD + 2 Decoders, Newclime Ceiling Fan).
See readings at 8.59AM this morning.
For the time being, I installed DC watt meter at output of my Battery Bank and another just before my CC to read-off harvest directly. While AC watt meter to monitor my AC loads.

An experienced explanation will do my nerves good.
Thanks
(Meanwhile, my inverter idle state is just 27.7w and has good surge allowance when fridge and freezer compressor kicks.)

GeorgeD, you are spot on. That battery is rated 925AH @ C20. The 20 hour rating is appropriate for solar applications since this mimics closely the duty cycle of the batteries in solar applications. Some manufacturers even use the 24 hour rating for batteries that are targeted towards the solar market. 100hr and 5hr rating are typically given for industrial applications, the 5 hour rating is used in industrial applications (Forklifts, aerial lifts, and floor sweepers), since they are only used in an 8 hour shift.


The Trojan Ind-17

GeorgeD1:


refa,
you're very much on point. and that has been my beef with the trojan ind-17 6v battery being sold by solarshop:

http://www.solarshopnigeria.com/homepage/trojan-ind17-6-industrial-line-flooded-lead-acid-battery-1202ah.html

on the surface, it looks robust with a high amp-hour rating of 1202ah but on careful examination, this rating is
based on 100 hours. the question then is: why this deliberate deception? and for a price tag of 535k?

The 20hr or 10hr just means that it is discharged to 1.75V per cell over a period of 20 hours or 10 hours while the total amp hour supplied is measured. But this does not mean a 20hour rated battery is necessarily better than a 10hour rated battery.

Example; Rolls Surrette S-605 L16 Battery is rated at 100hr for 605AH, 20 hr at 468AH and at 10hr for 398AH. Note that this the same battery, the only thing that changed here is the load that was used to discharge the battery.

So the numbers can make a battery look better if a 100 hr rating is given for a particular battery.

Because of the Peukert effect, batteries turn to deliver more AH if they are discharged slowly (low amperage draw) and lower AH if discharged fast (High average draw). So a 200AH at 10hr, may be better than a 200AH at 20hr.

mcTrinity:
please gurus, what's the difference between battery rated @20hr and the one rated @10hr..

Installed a battery rated @20hr... wanted to upgrade the battery bank and I got the same battery but this one now is rated @10hr. both 12v 200Ah.SAME BRAND!

what's the difference? can they be mixed

Thanks

What size of wire are you using?
Breakers are typically sized primarily based on wire size or amperage capacity of the wire in question. You can be producing 36A, if the wire used to carry this amperage is not rated for 36A, you are going to run into issues. On the other hand, if you wire is rated to carry something bigger than 36A; let's say 60A, you need to rate your breaker to protect your charge controller. Two ways to do this; Surge arrester and a breaker. Just my 2 cents

davodyguy:


Wait o Dam

9*4= 36 and we are using 32A.

Are my equipment safe?

I missed your post. I am really excited that someone located in the GH is also interested in Solar and is on this platform. I will be very happy to link up. refa.dodowa at google mail.

nene2016:
Boss. I am in GH and been following this tread too. Thanks to the big bosses like George. I am planning to use solar and I would be grateful if you could give me some pointers as to where to get quality solar in items in GH for installation. Please give me your email so we can talk more. Thanks.

Hi all,
I came across this and thought it will be an interesting read for the house.
http://blog.evandmore.com/lets-talk-about-the-panasonic-ncr18650b/

These are the same batteries in the Tesla vehicles & power wall, the Volt and the leaf use the LiFePO4 pouch/prismatic cells which is recommended by a few in other forums as it offers more cycle life than the 18650 batteries (Tesla battery). All these batteries have their down sides and advantages; Pb acid batteries won't burn your house down but the the lithium ion batteries have the potential to do that if the right charging parameters are not observed. That being said, if the favorable lithium ion charge/discharge parameters are observed; the cost per kwh in the life of the Li ion battery is cheaper than the Pb acid batteries.

Sorry for the late response, I was out of town. Yes all appliances are 110V including the Iron and AC. I still have a home in the states so I have access to 110V appliances for a steal.

shiftmarket:


Wicked. Nice one. Good engineering control although guys can use step up to beat that.
Your irons are 110V too?

Thanks to you all. I really feel at home here. I started with a 2000W 24V cotek inverter, a 30A Stecca PWM CC, 4X410AH (6V) battery, and 1400W mix solar panels. I need only lights and a few fans at the time for the place since I was living there less than half there only half the year at the time. It worked out well till battery maintenance started giving me issues. I had a few guys I had trained to do the maintenance, but neglected to do as long as they had lights. I sold most of my items to friends and family, used some to batter trade for building materials and when I replaced it with my current system; 8x430AH Crown Batteries, 3xMorningstar 60A MPPt CC, 1 Magnum 4448MPAE, 15x435 solar panels (these are rebranded Sunpower panels). I use the batteries for only Funs, TV, Lights in the night. The AC can be used during the day for about 4 hours and I do washing and ironing only during the day. The Fridge and the Freezer are on timers so they come on at 6:30 in the morning and go of at 7PM. The batteries are always are always between 50.8 and 51.2V in the morning. 2x35w flood lamps are on through the night and 6x35W flood lamps with motion sensors and photocell on all the time. I wired my place 110V since am not on the grid and most if not all my appliances are from the States. The 110V appliances also deters theft in my absence.

GeorgeD1:
refa,

welcome on board. i'm happy you found a home here.
please tell us a little about your system. array size? battery bank size?
charge controller type? successes and challenges with going off grid? etc
after all, we're all here to learn.

I have been following you guys for some time now (since 2013 0r 14). I am in GH and we don't have this camaraderie among the solar community. I have been off-grid since 2010; The cost to buy 12+ poles and pay arm and a leg to get power, prompted me to go solar and it made sense. You guys are doing such a wonderful job helping each other, answering questions. Dmerciful, GeorgeD1, Kiekie1, Abunafiu, earthrealm just to mention a few names that come to mind.

With regards to Solar harvest-we in the southern part of West Africa have a problem. Because we are on the equator we will have to adjust our panels every 3-6 months or so to get a good harvest. I have attached an angle calculator to help. You notice that the sun is in the northern hemisphere at one time and then in the southern hemisphere at another time of the year. That is-if your building is facing south, you will have it casting a shadow to back of the house at one time in the year and then casting a shadow to the front at another time of the year. To optimize your solar harvest, you will need to use a solar tracker or manually adjust your panels 2-3 times a year

http://solarelectricityhandbook.com/solar-angle-calculator.html

@Fikfik, I know am late to the party. Came across your Morning star issue and had to respond because I run into a similar situation. I have a 60A Tristar MPPT, run into the same problem. I managed to get it fixed. I still have some of the transistors that I used to do that do. You will need someone with a little background in electronics to do the replacement for you. I have surplus transistors for the 60A version hope you haven't thrown your CC away.The only unfortunate part is that I live in Ghana.