Off-grid system - 960W of 12v PV goodness - now what???

[Sunking]

If you are going to continue treating your batteries that way, you should just get a generator to run when you need power. Regardless which battery you chose, it will not give to it's ability if treated like that. Batteries need TLC to get the most from them.

Well stated and wise Flats. Most folks around here really hate hearing wisdom and experience. I have known you now for about 3 years now right? You have done well my friend.

[Outbackshackhack]

If you are going to continue treating your batteries that way, you should just get a generator to run when you need power. Regardless which battery you chose, it will not give to it's ability if treated like that. Batteries need TLC to get the most from them. The battery bank is by far the most expensive component of an off grid system even if treated with TLC, but it gets far more costly with poor maintenance. With poor treatment you might be lucky to get half the expected life published. Might be a flooded lead acid is not for you, some other types cost more but might take poor treatment better.

Hey maple flats Agree with you 110% and I promise I will take appropriate care of my new batteries. The past is the past eh?

[russ]

Hey maple flats Agree with you 110% and I promise I will take appropriate care of my new batteries. The past is the past eh?

The guys work hard at making people remember how important it is to take care - if it saves someone from wasting a set of batteries it is well worthwhile.

[Outbackshackhack]

All done!

My search for batteries led me to the Surrette 6CS25PS (6v 1156Ah) as my choice for quality, price and capacity. However, as luck would have it, there was a special on the 4KS21PS (4v 1556Ah) and they could be had for the same price for 12v as the 6CS25PS, so after checking specs on charge rates and solar panel requirements, concluded that I could make the 1556Ah ones work and ordered 3. I would need an 80 amp controller, twice the capacity of my existing one, but I also wanted MPPT, so I opted for the Outback FM80 with temp sensor. I wired my 8x120w panels into 4x12v pairs, totaling 48v.

Interestingly (to me at least), the batteries came uncharged. That is to say, they had electrolyte in them, but had not been connected to any charger (they still carried a whopping surface charge though, enough to run my place for a couple of days if I gave it a go ). I'm led to understand that this is best for the battery, as any charge pushed into the plates starts to age them. So I did just that and have pushed 100's and 100's of Ah into them so far. Man, they are like an Olympic pool to fill up! (doesn't help that I'm using them for power at the same time ) But filling up they are. I purchased a 4-stroke petrol charger as back-up. It outputs up to 70 Amps at 12v, so if I'm ever concerned about charge levels, I have options.

So this will easily power my home and office now, but without aircon. I will need to get creative on that and find a suitable cooling solution before December. I estimate at least 5 days capacity, more or less depending on many things. I am excited to watch the batteries' capacity go up and up from day to day - each day the end voltage is higher, and the number of Ah charged has increased in leaps. I added a good 2 litres of water to them at the start (they were only a smidge above the plates some of them) to the underside of the lids, and they haven't moved from there by very much. Hydrometer readings are all over the place - am I measuring at the wrong times? I figure that things will need a break-in period for things to settle down, so I'm not panicking at this stage. I'm away for a week so I'll check it all again when I get back. Good thing is there's only the fridge connected so the power surplus is big . I look forward to seeing where they are at when I get back next week.

The Outback FM80 is neat. Kinda like a fire or an aquarium to watch, as it works out in real time the best way to squeeze juice out of the panels. Very cool gizmo.

[Bala]

Its sounds like you have started using these batteries when they are not charged fully and not equalized.


Did you get an owners manual with them, or download the one off the website???

[Outbackshackhack]

Correct Bala.

This from Surrette:-

New batteries will give about 75% of the specified capacity until the battery has been cycled 20-30 times (1-2 months of service).

Further advice from the seller is to go right ahead and use them as they require cycling to get them to full capacity and it sure seems to pan out that way. No way the batteries accept anything like a full charge at first - in fact, the first day they rejected anything over 20 amps, last check they are taking close to 50. It is apparent that, even from new, the batteries need to cycle (or breathe even) to obtain their optimum capacity. Makes perfect sense to me.

[inetdog]

Well stated and wise Flats. Most folks around here really hate hearing wisdom and experience.

Maybe they are just getting a mixed message?

"Always listen to experts. They'll tell you what can't be done and why. Then do it."

A key point is recognizing the difference between theoretical experts' pontifications about what can or cannot work in a new way and the experience of practical experts of what does and does not work with what we have right now.

[Sunking]

Are you running at 12 volts with 1500 AH batteries?

If so WHY, that is nucking futs.

Secondly you are misinterpreting what Surrette specs are telling you. It is true they will not buil dup rated capacity until they have a few cycles like all batteries. But that in no way implies they do not need a good INITIAL CHARGE which sounds like you have failed to do and can quite possible damage your batteries. After each shallow discharge they need fully recharged each time.

[inetdog]

That is to say, they had electrolyte in them,.... I added a good 2 litres of water to them at the start (they were only a smidge above the plates some of them) to the underside of the lids, and they haven't moved from there by very much. Hydrometer readings are all over the place - am I measuring at the wrong times? I figure that things will need a break-in period for things to settle down, so I'm not panicking at this stage.

What did the manual say about that specifically? If the electrolyte was low because of evaporation of water, or the manufacturer shipped them with a lower volume of higher SG electrolyte to minimize spillage, then you add water to the level in the manual. If they had lost electrolyte because of spillage, then you would add electrolyte at the right SG, not water (after charging them so that the correct SG was known!)
Are the hydrometer readings all over the map from cell to cell, or just from time to time on the one cell you are measuring? They are expected to vary depending on the state of charge of the batteries (unlike some other battery chemistries where the electrolyte stays unchanged.) Also, if the battery temperatures are changing, be sure you are using a temperature corrected hydrometer or else correcting the readings based on the measured battery temperature (not the air temperature.)
Batteries will be warmer during and just after high rate charging or discharging. Even if you are using a temp-corrected hydrometer it is a good idea to measure and record the battery temp, since it will influence the charge current, energy available, etc.

[Outbackshackhack]

Wow I'm certainly getting a lot of FAILS launched at me! Which is weird because the company I bought everything from assures me I'm doing fine. You don't get all the info in just a few short posts, but somehow you manage to launch into judgement and criticism right away - seems like being right is more important to some of you than having all the facts.

But that's forums eh? One has to dodge the ammo from the egos of even some very knowledgeable people to find anything really useful.

Look, I know I can make my setup work, and my battery guy agrees and is only too keen to help. So all the FAILS are useless to me and I ignore them and the people they come from, which is sad because you could otherwise be a great resource.

inetdog, I followed procedure on topping up the cells. I didn't want to do it at all and my battery guy initially told me not to do anything at all, but the level was so low I couldn't even suck up any liquid with the hydrometer - barely a few mm above the plates on some cells. The manual says to add water. That's what I did. Battery guy agreed.

As for charging the batteries I'm doing the best I can. According to my battery guy (BG) this is what they do all the time. If I'm getting good sunny days there at the moment ( as said before I'm away) then there'd be at least 2.5-3KWh/day going in and maybe 500wh/day going out if that. Personally I think this is ideal and I will get a strong set of evenly absorbed cells from this regime. Of course, when I am back again the power draw will be closer to 1kwh/day or higher, but after nearly 2 weeks I think it is time to up the loads.

But I will get BG out to help me to ensure I'm reading electrolyte levels properly as I do have doubts in this area, especially since the levels were so low to start with. Also I need advice on equalising as I don't want to do it too soon or too late or not enough.

I don't know why anyone has to launch into FAIL FAIL FAIL - it puzzles me it does. Why not just say - "I'd be concerned about that and it might be a good idea to speak again to your BG..."? Egos.

[Sunking]

Outback try reading the Rolls Owners manual. Specifically the INITIAL CHARGE requirements. It will contradict everything your battery guy is telling you. So do you want to believe the battery guy, or the manufacture who made it and carries the warranty?

No one is competing for Browny Points or Warm Fuzzies here, nor does anyone really care if you damage your batteries as it is your problem to deal with. Try researching and start by reading your Rolls Battery Manual. One of the worse things you can do to a battery is to fail to give it a proper INITIAL CHARGE, and then keep it fully charged at all times. Once Lead Sulfate crystals begin to form on the battery plates and harden, there is no reversing the damage. Look it up yourself.

[Sunking]

But I will get BG out to help me to ensure I'm reading electrolyte levels properly as I do have doubts in this area, especially since the levels were so low to start with. Also I need advice on equalising as I don't want to do it too soon or too late or not enough.

The Initial Charge is an Equalizing charge.

Batteries are shipped two ways: Either Dry Charged and the electrolyte ships separately, or sent about 2/3 full at very high SPG to be diluted with water once they arrive to the proper level. The proper water level is clearly described and pictured in the Owners Manual and tells you everything you need to know.

[Outbackshackhack]

Well it sure sounds like I'm doing everything upside down, but I am not yet convinced that all is lost.

I'll discuss this all with BG (who has installed 100's of systems, but I don't think has letters after his name). If we think the batteries have been harmed and will not last, I will request new ones, fully charged this time. But I really don't think it will come to that. I may have added too much water and this would need to be remedied, but that may not even be the case.

I was surprised to not receive a manual with the batteries when they arrived, but I went online and got the Surrette battery care manual, but it was not as specific as the Solar Battery manual in describing the initial setup. This will be the first cab off the rank when I talk to BG next week - they should supply a manual with the batteries if it is THAT important to get it right.

Maybe it's just the Aussie's "she'll be right mate " attitude....

[Sunking]

I never said all was lost, I just said your BG does not know what he is doing or talking about. Any good installer instinctively knows as soon as the batteries are installed to give the batteries a good 24 EQ charge. If it is a solar system they should bring a generator to get the job done if there is no commercial AC power available

Sounds to me like your BG has never even bothered to read the manual or do any research on batteries. There is nothing unique about Rolls/Surrette batteries that requires special charging techniques, it is the exact same as any flooded lead acid battery regardless who makes it. Example here is another battery which over the years I have installed over 1000 units. It is a C&D MCT-II 4000 AH battery used in Telephone DC power plants. Click here to see the manual and scroll down to section 2 Part 1.1 on page 14 Titled Initial Charge.

I have been designing DC power plants and worked with all major battery manufactures for over 30 years in the Telecom sector and what I am telling you is common practice. It is not my way, it is the industry way developed over 100 years of trial and error by the experts.

You came here asking for advice. You got it and it was free.

[Bala]

No one likes being told what they are doing is wrong, forums can be a tough place. Most people dont read posts fully and cant be bothered typing essay responses.

So dont take it personally just deal with it and learn. I have had my system for 5 years and still learning and when its time for new batteries I will be on here comparing advice from here as well as the sellers.

My view is generally it does not matter how many systems your BG has installed his info needs to be checked some how and this forum is a good place. You BG sells them, if they dont last as long as they could all the better for him. people on here have no vested interest other than to give info. You need to decide from all the info you get, your manufacturers manual your BG and this forum, what you are happy with.

I have felt like a right twat on here at times but among other things Sunking has shown me how to correctly read the temp corrected SG chart in my manual, my BG never offered that to me, your BG did not even give you a manual. I think part of the problem is the BG sees that you have some knowldege, hes busy so assumes you dont need help from him.

You have just spent a lot of cash, you cant have too much info.