My new battery bank is not working?!

[MNJon]

Thanks to everyone so far for the help. I'll add some more detail here. This is now our full time home and due to our location must be off grid. I love it, but don't want the wife to lose patience.

I have 440ah total in the four batteries. I am going to add two more this weekend to give me 660ah. The batteries are new enough that I am hoping they will play nice together.

All components are brand new. The PowerMax Boondocker 75 amp charger coupled with my 2000watt Champion inverter generator is sufficient according to the engineer at bestconverter.com.

I have been through 5 cycles now and something interesting happened this morning. When I checked the voltage on the inverter it read 13.21 volts, previously it had not read any higher than 12.92 (both while on the charger). I have checked voltage with a Fluke multimeter a few times at different voltages and it appears the reading from the inverter is right on.

I bought a hydrometer and I plan on letting the batteries rest today and check the readings this evening.

We are using a small fridge that says 1.5 amps on the sticker. I tried using a timer but the wife wasn't happy when her milk was not quite cold enough.

Our dc lights in the camper may be a bigger draw as indicated. The are all incandescent bulbs and get HOT, so I think there may be quite a bit of draw there.


Ultimately what I would like to do until I can add solar is run my generator in the morning for an hour or so while we make coffee and breakfast and the wife and kids get ready for school. Then use the batteries all day until dinner time. Use the generator for a few hours in the evening while watching a movie and doing some computer work, then use the batteries overnight to power a couple fans. If I can do this I will be happy. My genset only needs about 1 gallon per 8 hrs use. So compered to my old house and lifestyle even and $4/gallon and 8 hrs per day x 30 days a month I am saving a bundle($120 vs $300-$400)!

[MNJon]

One more thing. I used 2/0 cable for all my connections up to the inverter. I have never heard this, but is it possible to use to BIG of a cable?

[MNJon]

Reading this morning off charger was 13.04 with no load.

[MountainDon]

One more thing. I used 2/0 cable for all my connections up to the inverter. I have never heard this, but is it possible to use to BIG of a cable?

No

[hpinson]

The bigger the cable the less voltage drop loss. 2GA should be great but $$$ and it may be overkill given the distances involved. It is what you would use in a deep well with a long run. Here are some cable size calculators for DC wiring.  I believe that a 5% loss is considered acceptable. Did you mention how long your cable runs were?

http://www.freesunpower.com/wire_calc.php

http://www.freesunpower.com/wire_calc.php

http://www.youtube.com/watch?v=pGL0NgfNGhU

[MountainDon]

We are using a small fridge that says 1.5 amps on the sticker. I tried using a timer but the wife wasn't happy when her milk was not quite cold enough.

I don't recall if you have said what type the refrigerator is it. The OP has a reference that the fridge is in the RV section. Is this the typical RV refrigerator or something else? RV fridges are meant to operate on propane or get the electrical power from the power grid; not batteries even if it has a 12 DC option. That is because the RV fridge uses a resistance heating coil to make the heat required to operate the unit.

I am guessing that this is an RV fridge running on 120 VAC from the inverter. In that mode the small ones, 2 to 3 cu ft will be rated at around 1.5 amps. That's 180 watts. And I'll be surprised if it does not run more than half the time, maybe up to 80% of the time, even more. 180 watts for 20 hours is 3600 watt/hours. That the AC watts, no accounting for inverter loss. That could be more like 4000 watt/hours with inverter inefficiencies. That is more than what we use in three normal days at our cabin. But then we burn propane for the refrigerator.

Four 6 volt 220 amp hour GC batteries wired for 12 VDC output have a total capacity of 440 amp-hours at 12 VDC which is equivalent to 5280 watt/hours. The fridge alone is enough to deplete the batteries in one day.

That's a guess so may be a total waste of time.

What exactly is the refrigerator?

[rsbhunter]

MNJohn, if possible, look into adding solar as you can afford..As this is your primary home, this needs to be a long term solution..if you have the solar exposure, it will work all the time you have sunlight....I know it's expensive, but when you buy the componets, make sure you get what will handle the voltage that your system will run on, 12, 24, 48 volt. I have mine in 24 volt as the wiring can be smaller gauge, it has less electrical loss in wiring, and from what i have learned, it is more effiecient as your voltage goes up....But, other than that, it might be worth checking into a 120 volt "energy star" small reefer...some of them can really save some power....please look into some of the other forums that deal with off grid energy production.....they will give you a load of info...not that the people here aren't willing, but it really is a complex issue , if it is to be your primary power source...and contray to alot of comments, it is NOT cheap, if you want reliabilty and longevity off grid.....rsbhunter

[MountainDon]

.... contrary to a lot of comments, it is NOT cheap, if you want reliability and longevity off grid.....rsbhunter

Yes. It is not cheap if there are more than a minimal number of lights and not much else. And cheap, or inexpensive, can be different for different people.

I still consider the approx $8 to 9K we spent to be a very good deal compared to the $55K to connect to the grid. There was also a 30% tax credit that helped with the cost of everything from the PV panels and the bolts that connect them to the pole mount, up to but not including the cabin electrical service panel. We were also fortunate in that our state, NM, exempts all components that make up the solar system from any sales taxes.

[alex trent]

Cheap or not cheap is another subject..really depends on what you want and need.  For a complete system to run a lot of stuff..like a "normal" house, $8K is not a lot IMO, but for me 3K would be a high end system and I need no more. Low cost does not mean cheap components or not enough power. There seems to be a lot of confusion about that.

But all that aside, you need to solve the existing problem first...that may affect you no matter what system you have. Now is the time to do it...the less things you have in the system the easier it is to ascertain what is the problem and the more flexibility in fixing it. I have a bit of the same thing and am doing that now. I think my system is OK, just that charging the last bit of amperage is a long process and runs the generator a long time for the last 10%. I will gate that sorted....think needs a few more batteries.

From your last post, it seems to me that you are relying a lot on your generator...if this is a full time house, that may get tiresome and solar sure looks like it is the way to go.  I need to run my generator twice a week for 3-4 hours..or maybe once a week if I get a few more batteries which I think will solve my current problems with slow charge at the top off by making a longer generator run (but less often) a lot more efficient because it will be charging 5 batteries not 3.

But my power requirement are really different than yours...lights which are all low wattage (I can light my place up with 60 watts) and a small fridge, plus a bit of computer charging. So while solar would be really nice, it is hard to justify..although I do hate the genset noise...and I have a lot of clouds. I need to do a good sun analysis to see just what it would take to build solar in.

[alex trent]

Here is what i am doing to isolate and ID my problem.

1. I talked to Trojan and the tech rep is going to get mack to me with the real deal on how much charging to 90% will hurt the life of the batteries. If it takes me from 1000 cycles to 900, that is OK and I think from my preliminary work that will go a long way to solving my problem.

2.I am going to fully charge the batteries..until the IOTA charge light indicate float for at least 4 hours.  Will pull the batteries and charge them on the grid for this.  Will wait 12 hours and check the voltage to see if it jibes with the 12.84 volts Trojan say I should have. From this, it looks like my batteries have been charged to about 85%, since my open circuit voltage after 12 hours has been 12.75. If so, that is my problem and the solution is available.

3. I also am going to run my inverter for 24 hours with nothing hooked in and not connected to the house box.  Want to see how many amps that uses. If 50 amps as I suspect it is, that is yet another problem to deal with.  That is 25 to 40 percent of my battery capacity just for the inverter. I do turn it off a lot, but still an issue. I need to see about lower amp users.

4. Finally, I will run my inverter connected to the house system for 24 hours just to see how much i lose there with just the wires and not lights, etc.  If vetting is done right, should be next to nothing...but who knows.

5. I also need to cheek my genet to see if it is giving the inverter what it needs to charge at capacity.  There is some thinking that non-sine wave generators cost a lot in efficiency...like a 20% loss in power front he charger.  Not real sure how i will do that yet, but should be a way.

Anyone know a meter that can check the amps running through a line.. My multimeter is limited to 10 amps and that will not do.  That would sure be useful. have not been able to locate a user friendly one that cost a reasonable about.

[MountainDon]

Meters

[MNJon]

I didn't think my cable size was an issue, but I am stumped. I thought the 2/0 was overkill, but at only an extra $ .30 per foot I thought it was a no brainer, especially if I was going to add capacity. My cable runs are short: 12 inches batt to batt and 36" batt to inverter. Right now I have them in a vented plastic deck box, but will be moving them inside to a vented closet before winter.

My fridge is a small residential fridge with freezer, and yes, it runs A LOT. I am going to replace it very soon. I looked at the energy star full size fridges and was apprehensive to buy one because I am afraid it will be too much of a load, but it sounds like it may actually be an improvement. Especially if I take alextrent's advice and put it on a timer. I would rather go this route than propane the more I think about it because if when I add solar the electric fridge should be fine.

I can connect to the grid, but at a cost of $23K for the privilege of paying a monthly bill I will pass (actually I have to pass as I don't have the $23K in cash, and if I did I would not give it to them!). In comparison I have paid:

Generator $499
Batteries $79 each x 4 (two ore coming this weekend)
Inverter $199
Charger $199
Cable and misc-$100

Plus a future $3K for 1KW solar setup for a total of approx $4,500 (not including tax credits). A relative steal!

[rsbhunter]

MNJon...Solar can  save money from grid tie, a break even, or even a small loss situation, even figured over years. You will find that most who are off grid are there because of expense of hooking up to grid..i know it would run way too much for myself, as i am 5 miles from the nearest pole.....If you're young, and you buy a system sized for your needs, you MIGHT save money...but don't plan on it. If this is your main living quarters, and you can honestly live with a minimum of elect. use, then you might get away with $1000.00 to $2000.00 system. When you start buying the componets that are the best suited to long term off grid use and high effieciency, they are costly.....Look into Morningstar, Outback, and the others that are in the buisness of serious solar and wind-hydro...Also, PLEASE try to get an issue of Home Power magazine (mostly solar info)...or a subscription...it is worth it's weight in gold for the infomation it has...My system is probably oversized quite a bit, but as this will be my only power source, and it is where i will stay when i retire, i need to have a 98% reliable system....I need to spend the money now, while i'm earning it.....rsbhunter

[rsbhunter]

As a note, do a search on google for energy star appliances, there are charts that show the different "tiers" of energy star ratings, and the average yearly use in energy....rsbhunter

[MountainDon]

Personally I don't believe you can run any refrigerator on 4 GC batteries. No matter the type of fridge it draws too much power. A Kill-A-Watt meter would confirm that I am certain.  I don't see a timer being of any use; it will simply force the fridge to run full time when the timer says "OK" and leave you with food that is warmer than it should be, IMO.

I believe your assessment of a std size energy star fridge being too large a load is correct. Too big for your system. You could look into converting a chest freezer to a fridge, but that only works if you can live with a chest type. I really don't like them. Or spend money for one of the Sundanzer's; but again they are chest types.

[rsbhunter]

Mountaindon, you are 100% correct....Although i do have a friend in Az. that is running a reefer and freezer on solar and wind.....BUT....he has a much larger battery bank, more panels and is VERY aware of monitoring the status constantly.....I have been on the phone with him when he's said"gotta go, need to start the generator" cause of low batteries!!! He also turns off the power to the fridge at night (around 10:00 PM) and when it comes on in the am, "normally" it's daylight, and the panels are producing enough to cover the additional power needed to bring the fridge to normal temps...but he states that the inside temp never reaches even close to a to warm temp....So each situation is different....Off grid is not a plug and forget lifestyle....but , there is a feeling of "freedom" if you can make it work for you...rsbhunter

[CjAl]

my semi truck has four 1200 amp interstate batteries and if i leave my mini fridge running when i come home the batteries are dead on the second day.

[MNJon]

I think I am going to purchase four more batteries this weekend for a total of 8 batteries and 880ah, with the intention of adding solar next spring. Until then I will use the generator and the 75 amp charger to keep them topped off. I will probably just have top go with the most energy efficient fridge I can afford and use a timer and figure out a system/schedule to keep everything safe. Fortunately we are in northern MN so I can set my stuff on the deck in November and it will stay frozen til April! That should help with my refrigeration.

I still think the old rv panel may be causing my excessive discharge. I am going to research it and abandon the rv components ASAP.

[alex trent]

Here is what i am doing to isolate and ID my problem.

Step one is complete..

Charged on the grid for 5 hours and got 12.84 volts on both batteries after a three hour wait...so they are charged to 100% as per specs.  Took five hours.  In 12 hours of sitting idle charge was down to 12.77 and 12.80 on the two batteries (12.62 is 90%)  so this is very high 90's.  Charged again for two hours and after three hours back to 12.80 and 12.84.

I estimate that I am at 90% (12.62 in about two hours of charging from 50% which is reasonable for me.  That is what i will do rather than doing another 3hours for another 10% to 100%.

Trojan tech rep says OK for a month of twice weekly cycles like that and then equalize.  I need to figure out how to get my Iota to do that..it is automatic after seven days on float, but mine will not be hooked [p continuously that long.

Next I am going to sort out the inverter draw and if my house wiring is robbing any (too much).

[alex trent]

Step two of my test to see what ails my system.

Was either bad batteries or some big current draw.

Batteries are OK. Sixteen hours after charge reading right at 100%.  Batteries OK,,,three Trojan AGM 31....300 AH

Next step is to find the current draw. Suspected my house wiring.

Wagan Proline 3000 inverter.

System feeds from inverter to house box.

For the test I disconnected it from the house box so if a problem there it would be isolated.

On the batteries and no load, from the meter on the unit:

A.  Voltage reads true to what my multimeter say.

B.  Amps are 25 to 30 onn inverter meter and not way for m to check this.

C. Watts out 250-350. Also on inverter meter and again not way to check.

So, this means under no load the inverter is pulling 30 amps. Specs say 2.

I also tested it under load with a known wattage device and the total watts (measured with Killawatt was real close to the inverter alone reading as above  and the device, so this is not just a no load anomaly.

Got message into Wagan.

Running inverter no load on one battery and will measure in an hour to see if took battery down 30 amps fro the 100 full charge.  If so, bad invert I guess.

[MNJon]

My situation is so similar to yours. My inverter meter was reading the same voltage as my Fluke meter everytime I checked. But with no load the inverter still said 25 amps. I will have to do some more research on the inverter as well. I know some others have stated that some inverters can be a big draw.

On another note I purchased four more batteries but before hooking them up I tested all 8 batteries with a hydrometer. the new ones read 2.75 and the original (still new) ones did  not even register. SO this explains most of the extremely fast drain. i dont know if I got a bad batch of batteries or what happened, but I will be exchanging them next week. I think I will only connect 6 however and use the other two elsewhere since 6 seems to be the max advised to use in a 12 volt application.

Keep us posted alextrent. I followed your advice closely when setting our system up so I am curious to see your findings.

[alex trent]

I ran the inverter with no load for 4.5 hours total. Batteries came down from 98% to 80%.. The 80% was measured after 1 one hour rest from any inverter load.  Just as a note, batteries went back up from 65% measured  immediately on inverter shutdown.  I figure the rested load is the correct one to measure.

So, in 4.5 hours my inverter used 4.0 amps per hour. Specs say not more than 2 amps for the inverter.  The meter on the unit continues to say it is drawing 30 amps, so this is not accurate at all. Since I am doing this on a single battery, had that bee the case i would be dead in three hours.

I did this in stages 2 hours on...rest 1 hour...1 hour on....rest 1 hour and then the final 1.5 hours on (actually a bit less than 1.5 here).  Measured after each stage (at one hour rest) and pretty much the same draw in each stage.... 4 amps.... a lot better than the inverter meter says but still way too much.

Wagan has not returned my inquiry yet. They may have a reason for meter reading and I am also eager to hear comments on the no load draw.

If I were running a big load, this would not be particularly irksome as the 4.0 amps of the inverter would be a small percent of the load, but my loads are small...on the order of 10 amps max, and more like 5 most of the time, so this is a big percentage.

I have another smaller inverter here (1500) watt, also a Wagan and will run this test this AM on that one. This one says less than 1 amp inverter draw.

[alex trent]

Have to read my previous post to have this make any sense.

I put a smaller inverter (1500 watts) of the same make..(Wagan) on a fully charged and settled battery.

Ran it 8 hours and after shutting down and letting the battery rest 1 hour...used 8 amps or a bit less...so 1 per hour or less.  Specs for this say less than 0.9 amps.

This is by calculation from starting and finishing voltages as read on a multimeter.  The inverter has no meter.  So this is subject to some error as 0.12 v on the meter is 10 amps, and a slight error in reading the voltage can be 4 or 5 amps.  Nevertheless this is close...a bit better or worse, still in the ballpark.

So, at this moment, looks like my big inverter is off the mark. Been used pretty hard outside in the dirt and rain. Waiting to hear from Wagan...two emails from me and still waiting...two days fom the first.  I have  place i can but one and return it...think I will do that and test it new and if bad take back.

Made in China...at least I did not use it for food or animal feed.

[alex trent]

Still no reply from Wagan and they did not answer the phone in customer service..got a message.

I talked to a guy here who tested his draw by the  inverter in no load...supposed to be less than 1.5 and is 6amps  by his meter.  None of us here have separate amp meters so we have to rely on the inverter meter (next States visit I will buy one). He was very taken back...never occurred to him to measure since he has a big solar system which keep hum topped off most of the time..likely runs his genset 15 time a year.

Is this a generally big problem or just happens now and then...mine has been used hard so that may be it.  My little one is right on the specs.

I am not thrilled with Wagan service but there is a place here with them in stock and a good return policy so I am going to buy a new one and see if that draws specs or higher and if higher we know it is the design.

MNJON..did you have a meter independent of the inverter to test your draw?

[MNJon]

I dont have a seperate meter. I will be adding one though.

I have another question. My inverter will not shut down until 10.05 volts. Where can I find a device to shut it down at a higher voltage (80%).