T-105's not accepting charge.

[birdhouse]

hello-
the details:
i put in an off grid solar system for my ranch neighbor about a year and a half ago. 
24v.
(twelve) 6v trojan T-105's in a series/parallel wiring.
outback VFX 3524
morningstar TS-60 MPPT.
(three) 245w 30.7 Vmp panels in series. 
grounded.
fused at all the standard spots. 
south central washington state.  3500 vert. ft. 
some trees blocking panels with winter getting the sun lower. 
water levels of batts within specs.  plates not showing, but not brimming either. 

he does leave his inverter on while not there.  apparently there was some mis communication where he thought i said to leave a very small draw on the system while not there as to put small cycles through the batts.  i don't know why i would ever recommend this, as given the harsh environment (cold) you'd want your batts as full as possible at all times.   

his system was working fine about a month ago, then the last time he was up the inverter started kicking out from LVD. 

i went by saturday to check it out.  batts were at 23.2 when i got there.  voltages of individual batteries were within .05 of one another. 

i had just purchased an IOTA 24v 40A max 27.2V charger for my system, so i quickly hooked it up to his system.  voltage jumped to 25ish pretty quick, and hit 26.4 within 20 minutes.  i left the genny running for ~4hours then came back and disconnected it.  the volts dropped and after ~10mins, they were down to 24.2. 

i believe the panels are working great, but it was hard to tell.  that day was totally socked in, and with the sun behind a tree (and fog), the array was still pushing 67w. 

he does use a 1500w electric heater for an hour os so when he first shows up until the wood stove starts to take over. 

any ideas? 

adam

[birdhouse]

forgot to mention-
we used my IOTA charger because he doen't have the "MATE" for his inverter (yet). 

i wasn't sure if the base programming of the built in charger in his VFX 3524 would allow a 3500w genny to run the charger or not. 

i figured it would be faster and easier to get a quick 40A into the bank with my IOTA jobbie. 

adam

[Simen]

The batteries might have stratified? With only light load and trickle charge most of the time, with occasional heavy load; maybe AGM batteries would be better?

Do he have an external temperature sensor on his Morningstar? With low temperatures, the bulk charge should go pretty high; close to 30V around freezing temperatures... Also; remember that resting voltage are often lower at low temperatures.

Has it been sunny at all the last month? A light load would deplete a battery faster than one would think... A search idle draw of around 0.25A (from Outback's specsheet) from the inverter would add up to 180Ah/month; full idle @0.83A would be 600Ah/month...

And your charger; 27.2V? That's just maintenance voltage @ 25deg. C.; it wouldn't put much amp into depleted batteries in just 4 hours...

[birdhouse]

i can't remember if i put an external temp sensor on the morningstar, but both the morningstar and batts are in an unheated shed, so that shouldn't be an issue. 

since the outback doesn't have the make just yet for programming so i don't think it is search mode, so pulling 20w continous. 

the light load was a 17w bulb. 

now the inverter is OFF, so hopefully the panels start to treat the bank right!

adam

[Simen]

I don't know the sun condition at this time of the year at your neighbour's location, but the panels have the potential to deliver around 23A under idéal condition, but that doesn't last long in these days (short winter days), and the sun isn't out every day either - is it?

37Wh * 24hours * 30days = 26640Wh/month (1110Ah@24V/month)- that's a vampire load that sucks...

I would have charged those batteries fully with a charger/generator, and give them an equalize charge as soon as possible.

[birdhouse]

simen-
you are correct that the sun doesn't shine everyday there.  as stated before, trees are now getting in the way of the suns path.  i think one needs to be cut down.  it's almost directly south of the array.  there is a morning (SE) window with no obstructions, but i'll bet it only lasts an hour or so. 

i don't live at this location.  it's more of a vacation spot.  i was entertaining 6 friends for thanksgiving, so didn't have a ton of spare time to get things charged as well as i had hoped.  i'm just hoping that they held at somewhere just above 24v after i left. 

with the inverter now being left in the off position, the bank "should" start coming back from the solar.  i think there is some good sun scheduled for the next few days. 

and yes, i agree that a solid equalize, or three, would be in order after this event. 

i believe the owner of the system is getting the mate for the inverter and a thick cord so he can dial his amps to match his genny. 

adam

[kitestrings]

Adam,

I think I'd be asking, or looking to see what else there are for loads potentially on the inverter, on the "ranch".  Even when "unoccupied" there can frequently be phantom loads that add up (TV's, DVD/VCR's, overhead door operators anything with an RF remote, also things with clocks, rechargeable tools, flashlights etc.  How about water pumping, heat tapes and the like ?  Could be something else wrong, but I'm leaning towards Simon's thoughts, that the load is not meeting production and little things are adding up.  If it were me, I'd suggest he dump the 1,500 heater.

It may take a series of deep charge/discharge cycles to recover them.  Hopefully you still can.

Good luck,   ~ks

[birdhouse]

If it were me, I'd suggest he dump the 1,500 heater.

It may take a series of deep charge/discharge cycles to recover them.  Hopefully you still can.

maybe the space heater is just the ticket to get the deep discharges after the hard genny charge/equalize. 

so if he gets a mate and gets to doing some charging, equalizing, then discharging ect routine, what is the best way to do this?  i've never learned much about reconditioning batteries, as i've never had to do it.

i'm guessing you'd want to charge to float, then equalize for a few hours, then water, then wait?, how long? then discharge?  how far?  23.8 after resting a bit without a load? 

then repeat?   how many times?  guessing this could take days, and quit a bit of petrol! 

i'd do this for him, but i'm swamped with work.  he lives a lot closer and is getting pretty savy with this stuff.  so long as the instructions are very clear. 

thanks for all the info guys!

adam

[kitestrings]

You might want to check with the Trojan to see what they recommend.  I also had this book-marked from awhile back:

http://support.rollsbattery.com/support/articles/5964-battery-sulfation

It's dated, but a guy named Michael Hackelman has a pretty good book on battery care.  My experience is that particularly new users under-estimate the time it takes to fully charge; particularly the last 20%.

Good luck,
~ks

[birdhouse]

ks- thanks for the link.  that's some good info. 

adam

[dnix71]

Wow kitestrings. Rolls recommends breaking down hard sulfate by charging to 2.6 or 2.7 volts per cell with limited current. That's more than double voltage. You would need a special charger to do that.

[birdhouse]

Wow kitestrings. Rolls recommends breaking down hard sulfate by charging to 2.6 or 2.7 volts per cell with limited current. That's more than double voltage. You would need a special charger to do that.

that would be 15.6v for a 12v system,  or 31.2v for 24v ect....

sounds pretty normal to me...

adam

[Simen]

If it were me, I'd suggest he dump the 1,500 heater.

It may take a series of deep charge/discharge cycles to recover them.  Hopefully you still can.

so if he gets a mate and gets to doing some charging, equalizing, then discharging ect routine, what is the best way to do this?  i've never learned much about reconditioning batteries, as i've never had to do it.

i'm guessing you'd want to charge to float, then equalize for a few hours, then water, then wait?, how long? then discharge?  how far?  23.8 after resting a bit without a load? 

I would drop the discharge/recharge bit; such exercising works better for NiCd/NiMn cells

One good, proper equalize, after a full charge is all it takes. Rolls have more good information on this subject:
Corrective equalization instructions
Calculating corrective equalization time

Edit;
His Morningstar controller should perform an equalize once a month - as long there's enough sun, that is. The Morningstar tries to do an equalize for 3 hours after a full charge. if it can't complete the 3 hours, it will try again after the next 5 charges, before giving up (or succeed.)

Now, during the winter months, one should keep a close eye on the batteries...

[dnix71]

My bad Birdhouse. 2.1v +/- per cell is normal. Still, I don't have a charger that will go above about 15. My battery set is showing it's age and I need to do a day's worth of equalize/desulfating. I have off work tomorrow, so that's on my to-do list.

I need to water mine anyway.

[Isaiah]

Hi
you guys might want to take a look here
http://www.thebackshed.com/forum/forum_posts.asp?TID=2979&PN=1
  dnix you might want to look at a flee market for a good old charger rather than these new smart chargers.
 the old ones with the metal rectifiers can be updated to solid state rectifiers and work quite well, that is the biggest failure of old chargers, the coating comes off those metal rectifiers. wee haven't had any luck restoring those old rectifiers  just convert the charger to solid state.
 Isaiah

[Simen]

Some good info in that thread, Isaiah!  A couple of advice there that needs to be here; keep the battery and its connections clean! Wash the top of the batteries with some baking soda to get rid of acid spill, and make sure the connections are tight.

A good and cheap way to make an equalize-charger, would be to take any old lawnmower engine or similar, and pair it up with an old car alternator, where you rip out the regulator, and just control the field with a rheostat. Hook up a volt- and amp-meter, and you got yourself a DeLuxe manual charger-equalizer unit

I did that, and it has worked nicely for years... But at last run, i ran out of gas, and i was tired of the B&S racket, so i replaced the engine with a 3-ph motor. (I did a Story over at the MicroCoGen site awhile back; browse back to first post to get the whole story..)

[kitestrings]

Isaiah,

I agree.  This was a good read.  Many years ago I remember trying to resurrect some Surrette batteries that I got hold of.  I followed a similar 'recipe'.  Don't remember the details, but it involved individual charging (initially at fairly high charge rates, monitoring temps) and baler wire on a broomstick.  I still think once sulfation reaches a certain point - and that may not be the case with Adams yet - you have to do some electrical "jarring" of things to make any progress.

I also remember working on an equalizer/balancer once where there really was nothing wrong with the equipment, but one bad connection was causing the equalizer to function very erratically.

Got to admit Simon, I've never visited the MicroCogen site.  Got to visit this side of the forum more often.

Thanks for sharing.

~ks

[Isaiah]

Simen and Others
Awhile back Glenn the owner of the back shed gave me permission to post that battery thread on another forum , we didn't get it accomplished,
 if there is interest enough here we could readdress the issue  again???
 That Kind of computer work is beyond me, some that knows what they are doing would have to do it.
 look at how many hits that thread has, there are a lot that read it and don't post,