Power from Solar + Measuring Energy Balance

[peterwilliam]

I have a lagoon 420 on a swing mooring in Lake Macquarie Australia. It 1260 Ah of lifeline batteries with 400 watts of panel controlled by a blue sky MPPT controller. I am running just one fridge and it is struggling to kep up also. The panels put out 35 volts and the same current from each panel. What troubles me most is that the highest voltage I get from the controller is 13.1 volts and with batteries down around 50 Ah they only charge at around 7 A which drops to 3 amps if the fridge comes on. Does this sound like a controller problem?

[newhaul]

Originally Posted by peterwilliam

I have a lagoon 420 on a swing mooring in Lake Macquarie Australia. It 1260 Ah of lifeline batteries with 400 watts of panel controlled by a blue sky MPPT controller. I am running just one fridge and it is struggling to kep up also. The panels put out 35 volts and the same current from each panel. What troubles me most is that the highest voltage I get from the controller is 13.1 volts and with batteries down around 50 Ah they only charge at around 7 A which drops to 3 amps if the fridge comes on. Does this sound like a controller problem?

Actually no it doesn't sound like there is an issue at all you have 1260 ah bank and 50 ah is less than 5% of the total so the controller sees your batteries at 95% charged and goes into float mode.

[redpointist]

If you have 2 people available, perhaps you could shade each panel one by one and the other person can watch the charge controller to see how the amps going into the panel changes. That seems like an easier method than unhooking them unless you have one of those clamp on multimeters already.

[peterwilliam]

Problem is I lose about 30Ah every day. Even then I still don't get above 13.1 volts. Also the IPN pro remote shows the charge status as bulk?
I do have a clamp meter and current is the same from each panel.
Further if I use the generator to charge the current steps up and the voltage goes to 14 volts.

[Captain Bill]

I would test each panel to make sure you are getting power by doing the towel test. It's best to do this when the batteries are accepting a bulk charge, not so good in float or acceptance mode. Have someone place a towel over each panel and watch for an amperage drop. If you don't get one that panel is not contributing to the output. I assume you had the panels professionally installed. That does not mean each panel was wired properly. I helped a guy out in the Bahamas that had a busted panel. He replaced the old panel and wired the +and - to the proper terminals but got no increase in output. He was wondering why so I offered to take a look at it. His new panel was wired correctly but failed the towel test, so we started tracing wiring. When we looked at the junction box in the original panel which he had not touched we found the problem. The wire from the new panel was attached to the wrong terminal. We moved the connection to the proper terminal and the problem was solved. He had more power than he had ever seen. His original panel had never worked, he just didn't know it, because until he had to replace it he never tested it. It is quite possible that in the maze of wires required to hook up 8 solar panels something got fouled up. The towel test will tell you if all the panels are contributing.

[newhaul]

Originally Posted by peterwilliam

Problem is I lose about 30Ah every day. Even then I still don't get above 13.1 volts. Also the IPN pro remote shows the charge status as bulk?
I do have a clamp meter and current is the same from each panel.
Further if I use the generator to charge the current steps up and the voltage goes to 14 volts.

OK what controller do you have and what is the float voltage set to sounds like it needs to be adjusted

[b_rodwell]

I put a hold on measuring stuff because I have a more pressing problem. I had 6 new batteries installed (fulmen fg1406) a week ago. One of the previous posters pointed out that they are starter batteries. I am currently going back to the supplier/installer.

[b_rodwell]

My installer has come back to me. He says:
The batteries supplied can be used for starting or deep cycle.
I could only get superior deep cycle performance by going to gel batteries at twice the cost.
The batteries are identical to the Exide batteries that came with the boat and he removed. Fulmen is a rebranded Exide.
He uses this fulmen battery model in a charter Lagoon that he runs.

Sounds plausible to me.
Any comments from anyone that is more expert?
BTW thanks for all your responses. I am working through them.

Brian

[Trim50]

Hmmm..."can be used for both"...not a true statement.

[blackswan555]

Ideally the OB needs wiring for the panel VMP to be around 12v higher than charge voltage (12v systems) So series pairs, then paralleled for yours, you will get power earlier & later in the day and should see a reasonable increase throughout, Also the default settings are too safe, The default absorb is only one hour, should be more around 4hrs & charge voltage is too low for most batteries "to be on the safe side" Refer to bat manual for that,
Also often overlooked is the battery temperature sensor, I can not stress enough how important it is to have them on all charge sources, Batteries are spec'd at 25c, warmer, you have to lower charge voltage, cooler, raise it, in an extreme case it can lead to thermal runaway with "messy" consequences, on the cool side, you will constantly be undercharging your batteries,
Panel output, as mentioned maybe you do have one down but there are other things to take into consideration, panel's are also spec'd @25c and 1000w psqm of "Direct sunlight" here in Ibiza at this time of year, around 850w psqm is peak, the panels will be warm and they are off axis,
Outback forums if you need more help,OutBack Power Technologies User Forum • Index page (I am same name) If you are around Santa Eulalia, give me a nudge, I have a clamp meter if you need to use,
Have a good one
Tim

[Stu Jackson]

Originally Posted by b_rodwell

My installer has come back to me. He says:
The batteries supplied can be used for starting or deep cycle.
I could only get superior deep cycle performance by going to gel batteries at twice the cost.
The batteries are identical to the Exide batteries that came with the boat and he removed. Fulmen is a rebranded Exide.
He uses this fulmen battery model in a charter Lagoon that he runs.

Sounds plausible to me.
Any comments from anyone that is more expert?
BTW thanks for all your responses. I am working through them.

Brian

Trim50 is right, your guy is plain wrong.

Here's why:

What Is A "Deep Cycle" Battery? Photo Gallery by Compass Marine How To at pbase.com

[sailorboy1]

Originally Posted by b_rodwell

I have 8 x 120 watt HP-flex panels. Should be 960 watts. The panels are mounter horizontally at the back of the boat where there is little shading. I have an Outback controller. I am in the Balearics and on a sunny day with low haze the best power I have seen is 40 amps at 14.1 volts output. This is 564 watts. Is it normal to have this sort of discrepancy between the advertised power and the observed power?

What was your battery state of charge at the time and what is it normally in the morning? What is the capacity of your batteries?

When my batteries (and the controller output) have gotten to 14.1V they don't take much current because they are charged. The only time I see close to rated output from my controller is if the batteries are fairly low and can accept rated output and the sun isn't out till mid day to delay slower charge till then.

[hellosailor]

Brian-I would suggest you contact Exide, or look at their web site, and see just what they sell that battery as. Simpolified, the way it works is that a battery with thin plates can put out a great impulse charge (good for starting motors) but the thin plates literally fall apart more quickly, because they are thin and not as robust as thicker plates.
Then there are deep cycle batteries (and golf cart and "traction" and other similar types) which are made with thick, physically robust plates, that can better withstand the way that deep cycling tears away material. But the tradeoff is less impulse power for starting loads. IF the battery bank is large enough, that doesn't matter because there is still ENOUGH impulse power to be used for starting. So, an 800AH deep cycle bank won't care about being used as a starting battery, but a 60AH single deep cycle battery might.


In between the two types there is a third called "dual purpose" batteries, which are sold for both purposes. The translation of that is "this is really neither fish nor fowl, but it will hold up better than a plain starting battery and it won't cost as much as a true deep cycle, or last as long under heavy loads."


It sounds like your batteries are "dual purpose" and if that's not what you asked for, it is NOT what you should have been sold. Regardless of the brand and name.


If the numbers, including the price, add up and you're happy...that's what counts. But if you wanted deep cycle and these are "dual purpose", they won't be the same thing.