I feel like an oxymoron

[jmk]

 I purchased my first set of Interstate UL 16 6 volt batteries in July. They read 25.1 volts when first hooked up. I am new to this re battery stuff and thought that they needed to be 28 volts for a full charge. I just had raised my 12' turbine up and was excited to charge the batteries to 28 volts. I never really got consistent winds to get any higher than 26.5. The winds would calm down and the battery would settle back down to 25.3 volts I haven't figured out the dump load yet because it needs to be about 1,500 watts. I figured I would run the turbine only while I was at home and use power up as needed. The winds started out about 5 - 10 mph in the morning with the mill kicking in around 2 -5 amps. When I checked the voltage in the morning I noticed that the volts went to 27 without anything drawing currant. So I ran a cord over to the fridge and plugged it in. The wind is starting to pick up more and the draw only dropped the volts down to 26.5. While the fridge was running I started to get 5 - 10 amps coming in and it brought the voltage up to 27 again. Now I plug in the chest freezer and it draws it down to 26 volts. The wind is up to 14 - 20 mph and getting gusty. I am now getting short surges to 40 amps and the voltage is shooting up to 28.2 or so and going back down to 26.8. So I plug in another fridge. I ran that for about six hours with amps coming in from 10 to 40. Anyway when the wind started to die down I started unplugging stuff. The wind just about got calm around sunset and I figured I would unplug everything. The voltage was at 26.2 . I came out to shut down the mill and noticed that the voltage shot back up to 27. I plugged back in one fridge and went to bed. I got up a couple of times to check it and it was the same. In the morning the voltage was 27.5 so I ran both the freezer and fridge with no wind no amps coming in. I want to get the voltage down to 25.2. By noon The voltage didn't want to go below 27. I figured this cant be right so I unplugged everything and went to the hardware to get a hydrometer. When I got back The volts were 28 with it just sitting nothing plugged in turbine off. I checked the sg and it read 1.15 in the red almost at the bottom. I can't believe it, so I go bye another one. It says the same thing. Why would this be?  What do I do now

[wpowokal]

OK there are cheep and quality hydromiters.

Why oh why are you frightend to let your volts go above 28V? The voltage you are seeing is surface charge it takes hours at voltages in excess of 30 volts to equalise all bateries and bring the specific gravity up.

Read

http://www.homepower.com/magazine/downloads_batteries.cfm

Then read some more, it sounds like you are murdering your bateries.

http://www.sandia.gov/pv/docs/BattIntro.htm

allan down under

[Flux]

Allan is right. Your batteries will be fully charged when a current of less than 5A brings them above 29v.

When you have 40A going in, you will not be able to absorb that even in the bulk charge phase unless they are well down.

As you come into the absorbtion phase you will need lower and lower current to prevent excessive voltage and it will be necessary to limit the charge current to keep the volts just over 28v (that is just what a charge controller does).

Try to pick a day with reasonable amps(5 to 10) and let them charge up and equalise.

Let the volts sit at 29 to 30v until the sg rises to its maximum value.

When they are fully charged then try to keep the sg as high as possible without letting the volts go much over 28v for significant periods.

Sort out a charge controller as soon as possible.

Flux

[wpowokal]

Just one more point, the only stupid question is the one you do not ask. Yea I know an old one but still very relevent.

allan

[jmk]

 I am going to hook up my inverters ac in to the grid power and let the 24 volt charger brings them up. I should have done this a while ago, but I wanted the turbine to charge the batteries. I just bought the # 6 wire to hook it up. I have to get a 60 amp breaker according to the Xantrex manual. I have a C-40 controller. I know now it is a bit on the light side. I was thinking of getting a 2,000 watt resister from the alternative energy store to handle the dump load. I got the Idea from a post Dan B commented on. http://www.fieldlines.com/story/2006/7/26/22138/3687  I hate the idea of wasting the dump load power, but it looks like the way to go. From my understanding it wouldn't really doesn't heat that much water anyway, even if they did make a 24 volt element in the range that I need it in. The resister has to give off heat I would think. Maybe I will poke some wires trough the wall into the house and put it on the inside living space.

 If the bank wont absorb 40 amps then the machine might as well furl at like 20 amps? What if I had the eight batteries, would it be able to absorb it then? Right now without a dump That must be like waves of heat in the stator, right? I have a lot of wind coming in the winter, and I am glad I figured this out now. I hope I didn't hurt my stator. If I had about 20 amps of draw wouldn't that take half the 40 amps, and then leave 20 for the battery, and so the battery might only take 10 amps in and leave the rest in stator heat? Am I thinking right now? My thought is that if I have 20 coming in 20 going out it would skip right over the battery and into the inverter, right? I don't need the stator getting hot. I will finish hooking up the controls. I thought I was in control, but I guess I am a little nigh eave. I am trying to read and learn everything, but it hard to know when you don't know that you don't know.    

[Gary D]

Trace/Zantrex C60 or a Morningstar ts 60 will give you the dump load capability you need max. for 24 volt system. There are water heating elements available to use with them for diversion. You just need to keep the total amps of any air or water elements below the max. amps of the diversion units. The trace and/or morningstar are each less than $200 bucks, and each water heating element under $100 bucks at the altenergystore. I'm sure there are many options and web sites out there to help you out(unless you prefer to diy).... Gary D.

[Gary D]

If you already have a c 40, then a second one using slightly higher set points can easily do what you want. If you go to the altenergystore and type in the search "hot water elements", you'll find 25 and 30 amp elements. You could easily run two separate wires into the house and have a bit of spare heat on windy nights after your battery bank is full. If you charge up the batteries with the inverter, you will need a full diversion load immediately. Just a thought...

[jmk]

   I thought that because the batteries were new and kept dropping from 26.5 to 25.3 that the batteries were full and couldn't hold anymore. That's why I was trying to use power as it came in. I wanted to play with the new system so I could watch the turbine make amps. They say that a full battery is 25.2. These batteries are a learning experience. After spending a $1,000 on them I thought they would have a manual. I know now that I should check the sg and volts. I should have hooked the batteries to a grid tied charger as soon as I hooked them up. I was scared to hook the ac in up to my SW 24/40 Xantrex inverter. I wasn't sure if this was considered grid tied or not. I called support at Xantrex and they told me to hook it up. Its like hooking up a large appliance. Nothing to do with selling power back and being grid tied. It's a nice feature of the inverter. It will keep the batteries charged and spill direct ac to loads that the re can't keep up with. This way the batteries stay full. I'm not even going to run the turbine after I hook the inverter to the grid,( hopefully today ) until I get the dump load hooked up. Thank you for the links. I will study them. I think I am understanding what's going on now, but not totally. This battery stuff is very confusing! I hope I didn't harm the batteries.    

[jmk]

  I bought the C-40 to soon I should have waited till I figured the whole system out better. My plans called for a C-40 type of controller so I just bought it. I probably will buy another C-40. The only thing with hooking up two water elements is the water tank only takes two and my water will be cold then. If I just put them in a tub of water then I am just burning off the extra power and might as well just put it into one 2,000 watt resister that can be close to the controller  in open air.

[Flux]

Yes battery stuff is very confusing, especially volts.

The only time that volts give any indication of state of charge is when batteries have been standing without charge or discharge for several hours. Then about 25.2v indicates full charge.

If there is any charging at all then volts will be higher. If any discharge is taking place then volts will be lower.

If you are furling at about 40A then the C40 will be fine, but choose a dump load that will not exceed 40A. If you have a very windy day and you have an average of over 40A coming in and volts start to rise then you can switch a bit of load on.

State of charge of the battery is not going to significantly affect stator heating, the alternator doesn't know if it is boiling a battery or heating a heater. Heating in the stator will be determined by alternator design (resistance) and maximum current at furling.

Your batteries will take 40A when in low state of charge so you need not set furling lower than needed for safe temperature. More batteries will indeed let you charge at higher current to a higher state of charge and will also let you use more load for the same depth of discharge. More is better up to the point where you can no longer fully charge in a sensible time. In the extreme case of too much capacity you will not be able to supply the current to get them up to gassing volts except at infrequent intervals. This will require constant equalising from another source (inverter in your case). If you get good winds and you want to make better use then doubling capacity would make sense.

I doubt that you have done any damage to the batteries, but get the sg up as soon as possible and monitor it. If you have significant periods of low wind and sg falls, use the inverter to bring sg to at least half charge if you think there will be wind soon. If the wind doesn't come in a few days use the inverter some more.

Flux

[altosack]

Hello jmk,

While I prefer the TriStar, the C40 is a quality piece, and you will get good use out of it; don't feel like you bought it too soon. Also, there is no reason why you can't mix and match with another type. Go ahead and go for the TriStar for the other one; they're compatible, just set the primary at about 28V and the backup at 28.6 or so (for example; there are reasons you may want to choose lower or higher setpoints - also, if you calibrate them, there's no reason you need to have them more than about 0.2V apart, if that's what you want).

As you said, there should be 2 connections to put elements in your hot water heater. What I would do is replace one of them (the lower one) with a 24V element (try www.kansaswindpower.net or the altenergystore mentioned above), and eventually add another controller with an air heater as a backup system. Normal (?) 24V elements have a capacity of 1200W @ 30V or about 1120W @ the approximately 28V you will regulate at. While this 37A is higher than the NEC says you can use with 40/45A controllers, I would not worry about it too much, both have good safety factors built in. This will cover your wind generator the vast majority of the time.

This way you will get full benefit of your primary excess, and still retain your grid on-demand hot water. By taking out one of the elements, you will lose a fast on-demand recovery but this might not be that much of an issue for you.

Good Luck with your system,

Dave

[jmk]

  I hooked up the grid to the charger.It ran with three stages of a like moffit fan running as it got hot it would increased the speed. The voltage on the multi-meter went to 31.2 and then started fluctuating then it turned off the fans and held it.   I am in float level at 29-30 volts. I can adjust the charge so it will allow the turbine to charge. I won't let it run till I get a dump load hooked up.  I know that you aren't supposed to check the sg until it has leveled with nothing for three hours, it still reads about the same. I will let it run some cycles and see what happens. If you have been where I am now I would like some of your thoughts. My thoughts bring me back to earlier postings When I was wondering if they sold me the batteries that the big wigs wouldn't buy?  

[harrie]

Hi jmk, One can put as many water heating elements as you want into a hot water heater, by drilling holes in the tank with a hole saw, and welding a coupling in the hole that has the right threads to receive the elements you want to use. Of course you need to drain the tank, and take the jacket off to do this. Just a thought, sounds like your getting it figured out.

Great fun, Harrie

[stephent]

Just make sure your water heater is outside the home in it's "normal" position if you drill holes in it. They are usually "glass" lined to keep from rusting away in a year or less.

Welding a coupling/hub onto one will chip/break the glass coating around the weld site.

It will rust through a lot quicker then normal if the glass isn't protecting the steel.

[harrie]

Yes, you are right Stephent, I forgot that the new heaters are glass lined, I guess I have only did this to the older galvinized ones.

[jmk]

 Flux for some reason I didn't see this post? I didn't like the fact that the batteries are low. I let the inverter/ charger put a full bulk setting. It's in float now. I am afraid that even with the full bulk charge that the sg will not come up to full charge. I will try to let it go through some cycles.

 I was thinking of stoping it to let the turbine bring up the rest of the voltage but I think I have to let it go and get charged up at least once. I can do as you say on another cycle. I am just afraid the wind will wait to long. I think these batteries are going south, but well wait and see. I can't beleave the draw of curent that the charger takes. My wheel on the meter must have been doing 20 rpm! Yea go ahead, LOL! Now I know why they say you need a 60 amp breaker on a #6 ac wire!

 It's holding 30 volts in float. The bulk cycle won't be that bad on the grid meter next time. It should cycle faster. I have to set all the timings for how I want it to run. Bulk charges can even be set for time, so that you can do them in a time period where power is cheaper. To alot of you it must seem like I am cheating or abusing power.  I can set it so that the wind turbin can charge the batteries for six days a week and if they don't hold up it will do a once a week charge. I guess this is all fine and hunky dory if I have a good dump. The only problem,ehm, cough, just a fraise, is this darn inverter has about 400 settings! You can only read it before to long it all starts eraising prevease comprehension! It reminds me of fighter chief school without my instructors. I do have you guys though, thank god! I guess only people with SW inverters might get what I am talking about. Pluss taking it all on and trying to do my job, and only being in it for well, I will have to say two years now. Sure you say two years! well I spent most of it learning how to build the turbine. Well,I guess I am just making excuses for asking for help. I apreciat all coments. I had a couple of beers so if I seem out of line a little its because I am just getting loose. Cheers!          

[jmk]

 Flux are you saying if the machine furls at 40 amps I should have a 40 amp dump. I was thinking If I went with the resisters that the energy store sells I would buy the larger one. They come in 1000 and 2000 watts. (40 or 80 amps)

[jmk]

 I see, they do sell 24 volt elements in that range. If I set the tail so it furls at 1,000 watts I should be ok with one in the bottom of the tank. I heat my water for free in the winter with my wood boiler, but this would still help in the summer if I ever get the wind at that time of the year. It can help get the water hoter. That's alot better than just waisting it.

[SamoaPower]

Why would you want to spend more on a load that your controller can't handle?

Your C-40 manual suggests that you size the dump load to 80% of the controller capacity or 32 amps to allow for gusts.

I suggest that you do NOT try to run multiple C-40s in parallel in diversion mode. This will mess up the battery charging algorithm since they would not be synchronized. Remember, charging the batteries properly is the primary role of the controller.