Switching to float

[boB]

No multiple charging sources here Bob just 5 strings of 2 – 140W PV with the Classic 150 connected to a set of 6 Solar One 850AH- 2V cells.  I have gone back and looked at the logs for 11/8/2012 and here is what I see. Absorb is set for 14.5V

11:21AM  14.3V  241W  Bulk M  -- 16.85A
11:31AM  14.6V  227W  Absorb --- 15.54A
11:40AM  13.7V  109W  Float    ----  7.95A

Somewhere in the last 9 minutes the current must have dropped below my 15A EA for longer than 90 seconds. So maybe I should be setting EA lower. Hoping the battery monitor is around the corner. Would love to see it under the Christmas tree this year.

Yeah, looks like EA was satisfied there.  Those logs can be very handy for figuring this type of things out.

Unfortunately, Santa's elves aren't building battery monitors this year but I think he will be have them
ready by next Christmas...  If not before.

boB

[Vern Faulkner]

Came home today to find the controller in "absorb" mode, pushing 15 or so amps into the set of trojan 370 AH batteries. All the voltages have been set to meet the specific trojan suggestions.

What worried me is that the batteries were bubbling, audibly, as if they were on an equalization charge.

The controller would not go into float.

Should I be alarmed? MY EA is set to 3.7 amps (1 per cent of AH is a recommended starting point) but that wouldn't make a difference with the current being pushed through at 15A.

Following another thread here, I had minimum absorb time at 2hr, max at 4hr.

Now, we've had a buncha cloudy days here, but I have only seen the controller declare a full charge on two occasions. I'm growing worried (though voltages declare no worse than a 60% DOD so far.)

[boB]

Following another thread here, I had minimum absorb time at 2hr, max at 4hr.

That should be good.   You just need lots of sun or maybe some more PV ??

Bubbling is normal.  If they are bubbling, then it seems like they are getting to
a semi-high enough voltage at least.  Just check the water level and add more
if it gets too close to the top of the plates.

boB

[SolarMusher]

(1 per cent of AH is a recommended starting point)

Maybe 3.7A is a little low (don't forget to add your loads). Try to set it to 2% and check your SG first. Set it lower if you need to get your SG to 1.275.

(though voltages declare no worse than a 60% DOD so far.)

Never trust a battery monitor on voltage, always check your SG to know your real DOD.
As boB said, more PV would give you a 100% SOC more frequently in automn with short days.
A+
Erik

[Vern Faulkner]

Maybe 3.7A is a little low (don't forget to add your loads). Try to set it to 2% and check your SG first. Set it lower if you need to get your SG to 1.275.

Noted.

Never trust a battery monitor on voltage, always check your SG to know your real DOD.
As boB said, more PV would give you a 100% SOC more frequently in automn with short days.

SG matches voltages so far, so I'm only going to do SG readings once every week or two until I have reason to be alarmed. Looks like a sunny day, so I should be able to gain more data today. Hoping to see a float before 1 p.m.

As an aside, I've got 480W of panels feeding into the Trojan deep-cycles (370AH). This is the winter test setup, to gain a sense of what we have to do in advance of moving off-grid in, hopefully, three years. All I've read suggests that's a decent power input: am I mistaken?

[SolarMusher]

Hey Vern,

As an aside, I've got 480W of panels feeding into the Trojan deep-cycles (370AH).

What's your battery voltage?

[SolarMusher]

Vern,
For a 12V system, 480W PV sounds good to me. It's 33A into your batteries and close to a C10 charge rate for your 370HA Trojan.
It's just a rule of thumb but depending on your DOD, it should work fine.
Hope we're not talking about a 24V system...
Iced rain here today 
Erik

[Vern Faulkner]

Vern,
For a 12V system, 480W PV sounds good to me. It's 33A into your batteries and close to a C10 charge rate for your 370HA Trojan.
It's just a rule of thumb but depending on your DOD, it should work fine.
Hope we're not talking about a 24V system...
Iced rain here today 
Erik

No, we're at 12v for the moment. Not certain what I'll run with when we finally make the move to the off-grid home: certainly 24, maybe 48, and possibly with a small 12v system on the side for things that just plain need 12v (as in, maybe, a trigger for a small RV-style heater? Dunno.)