Did not think it out. Mixed system, SLA Batteries.

[UrbanWind]

Noob here, need some wise input for the borad elders about my setup.

Orgianlly I planned on a mixed system, a little solar, little wind.  Everything dumps to the batteries and a dump controller is used.  Plannd on Golf Cart Batteries.

Then you get one of those offers you think you can not refuse.  I got batteries at a good price I think.  I ended up with 13(Lucky) TC12-120S Power batteries.

These are SLA instead of the regular Lead Acid batteries as you all know (I did not think about it when I dealt for them).

From all the reading I been doing, these are probably not well suited for wind?  SLA's want slower charging and do not like high voltages.

My questions are.

Is that correct, dumping into these directly with wind / solar then using a dump controller would not be a good thing to do?

What would you recomend my configuration be with Solar (225 watts currently) and wind (Just an Amtek 30 and a Low Wind PMA currently).  I do have a Xantrex C40 controller I can use if needed.

Thank You

Jim

[SparWeb]

Well, it could be worse: you could be trying to mix lead-acid with NiCad.

You've obviously seen by now that the SLA's cannot be "equalized", while the flooded batteries need it if they're to last a long time.

I started writing assuming that you have some of both types, and trying to splice them together.  Now I realize that maybe you only have the sealed batteries.  Is that right?  If so, you're probably okay, you even have a spare (no matter how you connect them).

The C40 will have no trouble managing the charge of the batteries.  There's a jumper in there to set for AGM's, preventing it from equalizing them.

If you were to mix flooded and sealed, you'd have problems.  If this was "salvaged" stuff, then I'd say go ahead and put them together in separate strings, and set the C40 to manage them like "AGM" batteries.  Every couple of months or so, or whenever the wind is strong, disconnect the SLA's, disconnect the C40, and let the wind over-charge the flooded string of batteries for a while.  That's kind of managing the batteries manually, but at least you don't have to do it too often.  Not the best but if everything was free, then there's really no cost if you screw up.

I doubt an Ametek and one solar panel could equalize many golf cart batteries, unless it was really windy and sunny at the same time...

[UrbanWind]

Steven,

Thank you for the reply.

Right now only the SLA's will be used.   Yes, I have a couple golf cart batteries and a marine deep cycle battery I play with but my system I am now going to have to use these batteries.

They were not free but compared to the say $200 price tag on them they were a good price.   They did come from a managed backup unit that was being disassembled.

I worry about the wind part of this.   I can run the wind through the C40 and not worry about the batteries but if they get full and the C40 shuts down, then I have a wind turbine with no load on it.  Would it not burn up if we got high winds and the c40 shut down? (If I did not disconnect and short it)

Is there another way to do this that will work?

Thank You

Jim

[ghurd]

Connect the C40 in diversion mode.

Do Not connect it in solar mode.

G-

[UrbanWind]

G,

Do I not have the problem about High Voltages with the SLA batteries then?  They say never more than 14.8 and 40 amps max.

I know my PMA can do 63 volts(open) just looking at it.  The 30V ametek I have never had above 39 volts(open) so I am not so worried about it as I am with the PMA.

Jim

[ghurd]

Kirchhoff's Second Law, KVL, means the PMA can not operate higher than the battery and diode voltage.

The Ametek 30 voltage was never higher than about 1V above the battery.

The PMA voltage was never higher than about 1V above the battery.

The system voltage is clamped to the battery voltage.

If the controller is set properly, the dump load is sufficient, and the battery capacity is enough to handle the C40's time lag, then the battery will not see more than the controller's setting.

G-

[SparWeb]

You should read the C40 manual (again).  Start to finish.  No way around this, bud.

The questions you're asking now are answered inside.  Cure for insomnia, too, so you can't lose.  If for some reason you don't have a printed copy, you can download the PDF from the Xantrex website.

Once you're over that hurdle you'll understand what you need the big resistor for, and I suggest you get an ammeter, too, to keep an eye on what's going on.

Good luck.

[UrbanWind]

G

So to try and sum up what you said, the question I had

"Is that correct, dumping into these directly with wind / solar then using a dump controller would not be a good thing to do?"

is a false assumption, no matter what I have read or assumed, going straight in with everything and using a dump controller is the thing to do?  Is that what you are saying?

Jim

[UrbanWind]

Steven,

I have the manual, I have read it a couple times and on-line once even.  I can configure the C40 without problem to any configuration needed.  

My problem area is with the batteries.  If I had golfcart batteries I would not have questions, I would be generating power.   The reading about SLA batteries and their requirements is what has me asking questions.  I want to take care of them the best I can.   I have 1,440AH worth and do not want to replace them tomorrow or anytime soon.

Jim

[ghurd]

It is the thing to do.

Use appendix B for the voltage settings.

Configure the controller as a Diversion Controller.

The combined maximum charge rate is about 20A.  Should dump about 25A.

That means you need a 0.5 ohm 500W power resistor.

Or two parallel 1 ohm 300W resistors.

Page 9 shows:

Wind, solar, and hydro going directly to the batteries, with blocking diodes.

The controller is connected to the batteries.

The power resistor(s) is connected to the controller.

There are at least 2 manuals around.  If it is not on page 9, keep looking.

G-

[birdhouse]

jim-

as ghurd was saying above, your ametek and or solar panel voltage will not exceed the battery voltage by much.  in other words, you may be able to get 30, 60 or even 90 volts out of your motor, but once you connect it to the battery bank, the voltage kinda "self regulates" to the battery voltage, or just above it.  i am still pretty new to all of this, but that's what i got out of his message.  good luck and nice score on the battery bank!

[rossw]

Don't let it scare you.

[img width= height=]http://house.albury.net.au/07sep2006/thumb.MVC-469X.JPG[/img] This is my 48V, 500AH bank of AGM cells. I purchased them second-hand 3 years ago, and use them in my off-grid home, two home-offices, workshop etc.

I have PV (solar) and wind (1KW turbine). They haven't exploded, or gone into meltdown. As long as you're moderately aware of what you're doing, they're quite tough. My turbine will produce several hundred volts open circuit, but when it's connected to the batteries, they clamp it. A diversion load and controller will keep your AGM cells quite safe.