LivSol

No problem Chris. I just don't want anyone to be ripped off. The instances I am aware of happened in 2012/3. I cannot believe this guy is still out there up to his tricks. Amazing the balls on these guys, geez!

FYI - Mega Solar is Jason Sole. For those who don't know, here is a link to check out. Never do business with him. I know of several people personally that have been burnt. I only mention this to avoid any visitor for member here from being ripped off. https://gwstoreripoff.wordpress.com

All good advise here. I concur with the battery recommendation. It's a very good battery for solar! I would only caution that 2.4kw in panels will not be sufficient to recharge a 10kw odd nightly discharge(i.e. 200amps @ 48v). To put back 200 amps odd, you will need at-least 4kw in panels as there are also day time loads that need to be supplied. I feel good rule of thumb is 1000 watts for every 100 amp hours in storage (assuming a 48v system using lead acid based batteries)) i.e 400 amp hour battery bank odd, 4000 watts in panels. This is assuming your have sized the system for 30-50% DOD. Less DOD less panels. But, this is area and climate dependent. Costal areas have less sun that the Karoo as an example.

To be clear, when I referred to charge rates, I am talking about the T105 RE. AGM batteries can handle much higher charge rates, making them ideal for limited sun hour situations. It’s a matter of the internal resistance of the various battey types.

C5 is a little aggressive in my view. 35 amps i.e C6.5, should really be the highest in my opinion. C10 is the recommended rate, a balance between faster charging and battery longevity. The recommended range is C8 - C12. Also, the faster you charge the battery at higher amps and voltage, the longer the said battery will sit in the absorb stage of the charge cycle. Just things to bare in mind..

1-3% of C20 rating indicates fully charged battery. In the case of the the premium RE line, 3% of C20 is still not at spec, but is for other FLA’s..Clear as mud charging is....

Yes. Correct. But for the purposes discussed here i.e. charging off a PV array, there are limited sun hours and therefore higher voltages are needed. But also, in general the RE line seems to need a higher voltage than say the signature line under same conditions. I cannot explain this fully, but have found it to be the case.

Check Specific Gravity of the cells at the end of the day. This will tell you if the batteries are being charged adequately. Reading should be 1,280. In my experience the RE line from Trojan need higher voltages to reach full charge vs the signature line. But there are many factors. I would guess that at 58,8 volts at 7-8amps the batteries are not fully charged. But I could be wrong. Check the SG, its only way to know where you are.

Okay. A couple of things. The load test I set out should only last a short time about 90 seconds or so. Whilst the C10 load is being applied you monitor the battery voltage. The voltage should not sag past a certain voltage. 49v wold the the minuim in my view. However, wet cell, AGM and gels will all be different due to their respective design, age etc. it's a quick indication test to where you are. also, you can check the voltage of each battery as well during this test, to see if there is a battery or two dropping more than the others during the C10 load test. Taking C10 out the batteries for 45 min won't hurt them. Theroretically, you should be able to run that load for 5 hours and would then be at 50% dod. LivSol.

I assume as it's 48v that you have 3 strings of 4 batteries each? First issue is too many strings of batteries. How are these wired? Second issue is per your explanation above the absorb voltage is to low @ 55.4v for an AGM unless its very hot. Third issue is you many be under paneled for the depth of discharge of the battery bank. I am not familiar specifically with Narada batteries specs, so am speaking in general terms. Batteries should reach absorb voltage per the manafacturer specification and stay there for several hours to ensure full charge. Is this happening? You have 600ah of battery storage and 3700watts odd in panels. This is ok if your under 20 -25% DOD nighly. Otherwise you could battle to put back the used energy during the day with other loads etc. Hard to say not knowing where your located as sun hours, average daily loads etc all play a roll. Load test - charge batteries per manfacturers spec, and hold vlatgae for 3-4 hours or when battery tail current reaches c/1 (i.e 6 amps). Now apply a C10 load of battery rating i.e. 60 amps @ 48v 2900 watts odd. Battery voltage should not drop below 49v odd. If voltage drop significantly more than this, you have fading battery/s.

FLA will be much more economical than the others you mentioned. Side note- Gel and AGM batteries that claim high cycle life in thier marketing materials should be approached with caution, as the reliable brands claim far lower figures for thier versions.

Enertec are the SA distributors for Discover. And M solar are First National battery. If you do end up with two strings, look at the Discover TFL 3000 as an alternative to T105 RE. 8 batts vs 16 is less connections and thus points of failure. I am however a fan of the RE line but have had good result with Discover too. Don't rule out the 435ah Trojan. they were well priced for a time, if you can't find them in stock in SA, let me know, I can source a set from USA if need be, but will be a couple of month wait. Having one string is a bigger difference to life span than most think.

Another thing to consider - Design life - As an example, the Trojan RE-B will give you around 2500 cycles (i.e 7 years odd) at around 32% DOD (i.e 118ah). The design life of this battery is 7-8 years, so there is little point in designing for a much lower DOD as the battery will likely die from old age (or at least have significantly reduced capacity) before it has delivered it cycles. The Signature line 435AH L16 battery will give you (according to Trojan DOD chart) 2400 cycles odd at around 27% DOD (i.e 118ah), so a slightly shallower DOD due to increased capacity form 370AH to 435AH, BUT, the battery will likely fail from old age before it reaches 2400-2500 cycles. Of course there are other factors that will effect the above numbers, such as accelerated corrosion due to heat in summer and the very occasional 70% DOD cycle, and the fact that most of use use our batteries over a 13 hour period in winter and even fewer hours in summer, so right there one needs to adjust C/20 rating a bit to get more realistic numbers. If you can install the batteries in a temp controlled environment, thats a big win, and will go a long way to helping you reach manufactures spec cycle life. But this is not always possible.Being off grid myself for many years, I certainly understand the sentiment of wanting more capacity being able to let the belt out a bit, and the comforting thought of having 5 days autonomy, but it comes at a huge cost. Staring a gennie on the third day of cloudy weather while not convenient, is far far cheaper! From a cost perspective, sizing your battery bank to around 30% daily DOD seems best, with the examples given above. But there are other opinions on this, I just speak from my experience.Now, if you want more capacity, then you should look at a battery with a design life long enough to use all the cycles is has to offer at the DOD you use. Select a battery with a longer design life, like the M solar 2v cells, or Trojan industrial range, to name two I can think off off the top pf my head. If you decide to use two banks for budget reasons (which is totally understandable), use copper bus bars to parallel the two banks and ensure ALL cables are equal lengths and terminated correctly, and check the batteries more often, and install mid point monitoring! Also, have a look at the Discover tubular range of batteries if you decide on two strings, they make 215ah 12v with a long design life from what I recall and have floaters to help with watering.oh, and I would not convert to 24v, as this would be a penny wise and pound foolish move I feel. 48v is the correct way to do things.Just my 2c.

@ Chis Hobson - I feel you would be better off with one string of batteries, even if that means a slightly smaller bank resulting in an increased in DOD. The ability to charge and discharge a battery equally will greatly increase service life. @ 108ah draw per night, you would have a DOD on the 450 AH bank of 24% and a DOD on the 370ah bank of 29%. So only a 5% increase in DOD. If it were me, I would rather put in one 370ah bank than two 225ah banks, and yes, I have actually had both;-) There is a 435AH Trojan signature line battery the L16H-AC, the other choice would be the L16RE-B 370Ah. The RE-B may be the better choice, as it all round a superior battery to the signature line. Hence the jump from a 1yr warrant to 3 yr. Also, with 2 banks you will have 48 cells to water and check.

I have tested these at length (200ah version), and concur with plonkster.

Possible reason for the two different charge spec sheets is that Trojan did in fact change thier recommended charge current for batteries manufactured after a certain date. In addition, the SG spec of a full battery also went from 1,265 to 1,280. I forget what the date was but sure its on the net somewhere.

The only way to know for certain where you are with regard to SOC, is to take SG readings at the end of the charge cycle. Otherwise your guessing. You should measure the gravity in all cells to start off with, from there on you can use a pilot cell to get a quick idea of the whole bank. Absorb voltage should be adjusted using this method, as mentioned, each battery bank seems to have a personality . A T105 per Trojan is at 100% SOC at 1,280 @ 25deg In short, a hydrometer is a must with anyone who has a flooded battery bank.

VOC = 31.24 ISC = 8.77

Need to go up and check again, cannot recall. Will post tomorrow. Need to add another string in parallel, currently 3 Strings of 4 200watt panels - 2400 watts.

Thank you TTT, let's hope there are some floating around. Need more of the power.....

Hi all, Looking for 4 - 8 200watt panels to match current Solaire panels installed. Need to add banks and in sets of 4. Anyone selling or know where to source please help.