Surprised by battery water useage......

backroad

Re: Surprised by battery water useage......

I thought that I would just update my original thread here if nobody minds.....

My L16 batteries (qty of 12) and the new Outback 3524 and MX60 were installed back in March of this year (2007), hooked up to 6/90 watt panels & 6/130 Watt Kyocera panels, and I'm still surprised by the lack of water use, as in absolutely none added. I still don't have near enough panels to keep the batteries charge with our care not useage. Been having to run the generator almost every day to keep up. The old gas 5500/8500 watt generator worked it's little butt off using about 5 gallons a day to do the job. I've now got the old Chanfa Diesel powered, 8KW unit, back up and running. It does in about 3 hours what took the gas unit to do in 12 or more hours.

The 195 Changfa diesel is a noisy thumper, but seems to only consume about 1/4 gallon per hour. You just gotta love it.

The water level in the batteries has gone down a little, but still so very little. Just wish this truck driver was a bit smarter to really understand all this. But I am having a good time.

Now I need to decide on 6-12 new panels and maybe more battery reserve. I'm thinking about the possibility of going with the Kyocera 175 panels, or should I stay with the 130's? I'm definitely going to add another MX60....and probably at least 4 more L16's..........

I understand the the Kyocera 130's won't be available till after the first of the year. I probably need to call NAWS and talk with them, HUH?

Dennis in Bagdad..............................Az...

BB.

Re: Surprised by battery water useage......

Get a good Hydrometer (if you don't have one) and measure the temperature corrected specific gravity... You may not be charging the batteries enough.

Undercharging you battery is not good for its life either.

-Bill

crewzer

Re: Surprised by battery water useage......

Dennis,

Little or no water loss in the batteries would suggest infrequent and/or incomplete recharges. Using the big generator will hopefully alleviate that problem for now.

Since you’re planning to buy another MX60, you have the option of using both KC-130 and KC-175 modules to increase your array size. For example, you might initially buy three KC-175’s and wire them in series to the second MX60. As funds permit, you could buy another three KC-175’s to add to the second system. The second MX60 could handle up to nine KC175’s configured as a 3 X 3 array. And, when you can find another three KC-130’s along the way, you could buy those and add ‘em to the first system.

HTH,
Jim / crewzer

backroad

Re: Surprised by battery water useage......

"Since you’re planning to buy another MX60, you have the option of using both KC-130 and KC-175 modules to increase your array size."

Thanx Crewzer, that's pretty much the answer I wuz hope'n fer. Let me see if I've got this correct. If I install another MX60 in my system and group the KC-175 panels in three's, it doesn't matter that the new group puts out more watts than the KC-130's because it's on a different Controller?

I run the generator almost every day, but my current hydrometer has gone on a long walkabout. I had thought it was working well lately only to find out that it was hanging up and not showing the complete charge the batteries were getting. I've got to find a really good one now and also want to use some kind of volt and maybe amp guage to help me figure out the battery bank condition. I've been kind of guessing by what the Outback inverter has been telling me on the battery voltage. I've been showing a good 25.3 plus before I quit running the generator. Also going by the charging state after in quits equalizing.

crewzer

Re: Surprised by battery water useage......

Dennis,

Let me see if I've got this correct. If I install another MX60 in my system and group the KC-175 panels in three's, it doesn't matter that the new group puts out more watts than the KC-130's because it's on a different Controller?

You've got it correct! 8) The array voltages going in to the controllers will also be different, so using them on separate controller's will eliminate any problems.

...also want to use some kind of volt and maybe amp guage to help me figure out the battery bank condition.

The Xantrex Link 10 battery monitor is my favorite.

Have a great day!
Jim / crewzer

BB.

Re: Surprised by battery water useage......

backroad wrote: »

I run the generator almost every day, but my current hydrometer has gone on a long walkabout. I had thought it was working well lately only to find out that it was hanging up and not showing the complete charge the batteries were getting. I've got to find a really good one now and also want to use some kind of volt and maybe amp guage to help me figure out the battery bank condition. I've been kind of guessing by what the Outback inverter has been telling me on the battery voltage. I've been showing a good 25.3 plus before I quit running the generator. Also going by the charging state after in quits equalizing.

I am not quite sure what you mean here... If you are charging, I would expect you to be at 28-29 VDC while charging and around 30-31 VDC while equalizing.

25.3 VDC would seem to be a rested battery with no load, or an uncalibrated voltmeter, or if while charging, a way too low charging voltage/current...???

-Bill

backroad

Re: Surprised by battery water useage......

You are absolutely correct on the charging voltages. The 25 plus volts is the batteries about an hour after the generator has been shut off at night.

backroad

Re: Surprised by battery water useage......

When adding new KC-175 panels and an MX60 to my existing system, would I still use the new panels in three's, wired in series? This is how my old KC-130's are wired.

crewzer

Re: Surprised by battery water useage......

When adding new KC-175 panels and an MX60 to my existing system, would I still use the new panels in three's, wired in series? This is how my old KC-130's are wired.

Dennis,

Yes.

The KC-130’s (and your other old PV modules) are wired in series sets of three to create a “36 V” PV array (STC Vmp of each is ~17 V). As a practical matter, the typical bulk-mode operating voltage probably ranges between 40 V in the summer and perhaps 48 V in the winter. The MX’ DC-to-DC function automatically converts the array voltage into the appropriate battery voltage.

The STC Vmp of the KC-175’s is 23.6 V. Wiring three in series will result in a voltage (70.8 Vmp, operating voltage range between ~55 V and ~66 V) that would be roughly the equivalent of wiring four KC-130’s in series. Set for a 24 V system, the second MX will automatically down-convert this array voltage to the correct battery voltage.

It’s not possible to perfectly synchronize the operation of two MX controllers. But, you can get them close enough. Set the absorption-, float-, and EQ voltages the same on both controllers, and adjust one or both units’ “Vbatt Calibration” so that they display the same battery voltage.

Ideally, the FX inverter and the two MX controllers should share the same remote battery temperature sensor via a Hub (the RTS should be plugged into the FX).

HTH,
Jim / crewzer

backroad

Re: Surprised by battery water useage......

Crewzer, you're do'n it again............

Now I guess I need to add a battery temperature sensor, hub and a mate, huh? OR, is the mate really needed with only one inverter?

Check me if I'm ok again. For now I add groups of 3 KC-175's to the new MX60. In the future when the KC-130's are available, it would be best to add two more to my existing 6 and switch them to two groups of 4 to get the closest voltage to the new KC-175's in three's.....

I'm so glad you have soooo much patience.........In my next life, maybe I'll be an electrician or an engineer or maybe even an electrical engineer........

backroad

Re: Surprised by battery water useage......

It looks like NAWS has a minimum order of 4 of the KC-175 panels. How does this figure into the calculations?

At what point should I/could I consider another 4 batteries? It's going to be under a year from the original battery purchase before I might add more....

crewzer

Re: Surprised by battery water useage......

Dennis,

Now I guess I need to add a battery temperature sensor, hub and a mate, huh? OR, is the mate really needed with only one inverter?

Well, you have a couple of options. You can “network” the OutBack inverter and a couple of MX controllers via a Hub. They can all share the same RTX plugged into the inverter. A Mate (plugged into the Hub) will give you additional programming, control, and remote display features, primarily for the inverter.

Alternately, you can do without the Hub (and/or Mate), and just buy separate RTS’ for the inverter and each MX.

Check me if I'm ok again. For now I add groups of 3 KC-175's to the new MX60. In the future when the KC-130's are available, it would be best to add two more to my existing 6 and switch them to two groups of 4 to get the closest voltage to the new KC-175's in three's.....

My original idea here was to configure, say, nine 175’s only on the second MX, and to add additional 130’s to you existing array and MX controller.

Your present array is rated at (6 x 90 W) + (6 x 130 W) = 1,320 W. Adding another three 130’s would take it to 1,710 W STC. This is a bit over OutBack’s recommended limit of 1,600 W STC for a 24 V system, but, considering your warm location, it shouldn’t be a problem. Besides, if the charge current from the controller were to ever exceed 60 A, the MX controller’s default setting would electronically limit the output to ~62 A.

As you suggest, another solution is to build a second array from a mix of 130’s and 175’s. The Vmp of four 130’s in series would be 4 x 17.6 V = 70.4 V. The Vmp of three 175’s in series would be 3 x 23.6 V = 70.8 V. Close enough!

For example, you could connect six 175’s in two series strings of three each, and four 130’s in a another series string, and then connect the three strings in parallel for an array rated at 1,570 W STC.

It looks like NAWS has a minimum order of 4 of the KC-175 panels. How does this figure into the calculations?

Hmmm… Well, considering that you're an established customer with NAWS, see if you can work out a special deal with ‘em: a total of six 175 modules, four now, and two more later. You could wire the initial four as a 2 X 2 array to the second MX60 for now, and the array voltage would be high enough (47.2 Vmp STC, ~38 V or so operationally) for your 24 V system.

At what point should I/could I consider another 4 batteries? It's going to be under a year from the original battery purchase before I might add more....

Your twelve L16 batteries make for a battery bank rated at 24 V x 1,185 Ah… that a pretty good sized bank for a single 3500 W inverter. I’ve probably indicated in the past that your present 1,320 W STC array is only ~1/2 the minimum size it needs to be for the battery bank. Adding another 700 W (four 175’s) now will help, and eventually adding yet another ~800 W to 1,200 W will put you up into the 2,000 W to 3,000 W range for both arrays.

Mid-day bulk charge current from ~3000 W of PV to a 24 V system will be ~90 A, or ~7.5% of battery capacity. That should work very nicely.

If you are going to get another four batteries, you need to do it sooner rather than later, as your existing batteries are starting to age. But, adding more batteries now will result in a bigger bank that’ll be more difficult to charge.

If possible, I’d press ahead with a larger PV array instead of more batteries.

HTH,
Jim / crewzer

backroad

Re: Surprised by battery water useage......

Thanx a bunch crewzer.....

I think I'll forgo the $1100 worth of batteries until I need to go with more inverter, which will probably never happen unless at the point I have a good 3000/3200 watts of panels and It might be necessary to add the 4 more batteries. But If the current qty. Is enough in the long run, why add more. If in a year and a half or so I added the extra batteries it wouldn't really break my heart that it wouldn't be optimal for the new batteries sake.

I'll probably add the two RTS's for now and forgo the hub and mate cuz they are kind of spendy.

I was considering adding two more Kc-130's to my existing 130's/older MX60 and grouping them in two groups of 4 to get closer to the KC-175's in groups of three on the new MX60 and then add groups of three 175's as finances allows. This would put a limit of 8 130watt panels on the older mx60 and call it good there. Then I would probably limit my new mx60 to 9 of the 175 panels. Hopefully this would not overload the new controller.

This should allow me to add the use my 8 cu.ft. energy star freezer and one 120volt/ 3/4 hp. Mastercool unit on the roof to the rest of the existing amp eaters. Only using the smaller 24 volt swamp coolers in a worse case senario(they just don't cool enough here in the Arizona summers, & are pretty noisy). I don't believe the smaller ones would ever be needed as the mastercool unit is rated for a place of 1500 sq. ft and mine is only 1100 sq. ft.

looks like I'm going have about $6000 and maybe close to $7000 to spend on the upgrade before I'm broke again. This is our place of retirement and we don't want to have to worry about leaving an extra light or tv on too much.

This is getting nice, as I'm starting to see an end vision in site. Of couse nothing is truly ever done. After all this, it's just do-dad stuff, like battery monitors and auto generator stuff.(oops....that means another generator or lots of engineering to the existing Changfa)....I guess it's really not that bad to have to manually go out an start it. I have to do that anyway to use my welder and aircompressor on 220v.

Now can I start adding water to my batteries after all this...I'm feeling a little left out on the maintenance thing & it's definitely time for another cold adult beverage. Later.............