Battery behavior

[jmk]

  A month ago I bought four new UL-16 6 volt Interstate batteries. I hooked them up to the wind turbine to charge them up. When I first hooked them up the voltage read 25.1. I have been getting 50-100 watts in most of the time. With gust going to 250, 500, 750, and 1,000 watts so far. The voltage has gone as high as 26 volts when not gusting. The problem I am worried about is the voltage keeps going back down to 25.3 every time there is no wind. Did these batteries sit to long on the shelf, or should I hook a grid charger to them and put some better juice into them? I never pulled any juice out yet. Also I am wondering if I hook up my SW 2440 to my grid power on input only and not to sell power settings will I be considered grid tied? Will I need to get permission to hook it up this way? It has a strong battery charger that I would like to use. Do you think I have only put .2 volts into the batteries, or do you think they saw me coming and sold me the batteries that the shops wouldn't take? The turbine has been hooked up for about a month now, but its in turbulent air. It still pushes the amp gage to 2-5 amps consistently. When the leaves fall of the trees it should work more consistently at higher amps, but I am afraid that the batteries wont store the power.

[jmk]

 Here is a picture taken from standing on my roof. The blades hardly ever stop.

[jmk]

[Flux]

I suspect you are confusing two things.

A fully charged 24v battery when left standing with no load and no charge should read about 25.2v so if you are measuring things under those conditions all is well.

As soon as you start to charge the volts should rise and with plenty of charge and no controller to limit it it should get to over 28V.

With a small intermittent charge as you have for considerable periods it will be somewhere below 28v depending on the current. With a decent current going in (say 10A) for a few minutes you should be going over the 28v and start gassing.

If that is what you see then all is well.

Leave the battery with no load and no charge for 12 hours and if it is over 25.2v you don't have a problem.

Batteries are confusing things and I still don't understand all their strange goings on after 50 years. You will learn what volts to expect depending on whether they are charging or discharging and those voltages will be unique to your batteries.

All these voltage tables available everywhere are at best a guide and some batteries never seem to have read the table.

Flux

[jmk]

 Thanks flux, So, the batteries are full and can't hold more and I'm just spinning my wheels trying to get them up to 28 volts at a sit still voltage. I should start taking power out then and see what happens. They only seen 28-29 volts for maybe 15 seconds in a strong gust pushing the watts to 750 and above. Do you know if it is legal to put grid power on the input side of the inverter for battery charging incase I need to bring the volts back up after taking current out?  

[Ungrounded Lightning Rod]

Do you know if it is legal to put grid power on the input side of the inverter for battery charging incase I need to bring the volts back up after taking current out?

As long as the equipment connecting the grid to the batteries is UL approved for this sort of service and either plugged into an inspected outlet or wired into a circuit and inspected, you should have no problem with code enforcement, your power company, or your insurance company over charging the batteries from the line.

You may have a problem over the batteries, genny, and inverter if you didn't do THEM right in the first place.  But that's a separate issue.

[Gary D]

There might be an issue that hasn't been stated yet. When the grid power is energised, the inverter goes into a dormant state other than the battery charger. In the S.W. manual on the D.R. series anyway, this is called pass thru(?). So a standard outlet rated for 15 amps cannot handle your rated output (inverter possible output) plus your user adjustable charge setting, not to mention any other things on the same circuit (possibly tripping your house breaker). If you don't ever use anything on your inverter circuit while tied to the grid for charging this shouldn't be an issue. If you ever plan on having some load(s) on while grid tied, a dedicated 20 amp outlet would be much preferred. I'm NOT an electrician, just a Harry homeowner here. Opinions vary, just my 2 cents, use it or trash it as you see fit... Gary D.

[jmk]

 Yes, this inverter states that it will pull up to 35 amps with the charger. I was going to wire a seperate breaker just for it. They do state that it can be wired with just a plug for an outlet, but I don't see how that works with 15-20 amp breakers. With them stating that, I was thinking it would be like pluging in a regular battery charger, and I wouldn't have to ask for any permission from the power co. I was thinking I would only have to contact them if I were to feed power back to the grid.