What charge specs should I set the Classic 150 to for these batteries?

TucsonAZ

Thanks a lot, I'm pretty sure I can figure this out but want to make sure I'm correct. This is on a 24v bank and I'm assuming I simply double the numbers of a 12v bank. Also, what do I set the temp compensation on the Classic 150 to? Also, for any of you Classic owners, are there any other perimeters I should adjust or tweak in there?

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TucsonAZ

Re: What charge specs should I set the Classic 150 to for these batteries?

Nobody? I was also wondering, the Classic 150 was displaying "720 Watts" today in bulk mode, is that what is has coming in or what it's actually using?

Vic

Re: What charge specs should I set the Classic 150 to for these batteries?

The power displayed by the Classic is the power that is being delivered by the Classic toward the battery. It includes battery power being used to charge the batteries, plus any power drawn by the interter/s and inverter loads.

I know nothing about your exact batteries. From your Signature, these must be AGMs. AGM batteries often use -- 3mV/C per cell. BUT, I know nothing of your batteries, specifically. FWIW. Vic

TucsonAZ

Re: What charge specs should I set the Classic 150 to for these batteries?

Somebody has to know what voltage on a 24v bank for bulk charging, any other Classic users with AGMs?

Cariboocoot

Re: What charge specs should I set the Classic 150 to for these batteries?

TucsonAZ wrote: »

Somebody has to know what voltage on a 24v bank for bulk charging, any other Classic users with AGMs?

You have the specs for the battery from the manufacturer. 24 Volt systems are just 12 X 2. Often the specs are given 'per cell' and need to be multiplied out by he number of cells: 6, 12, or 24.

It's odd that they give an EQ Voltage as that is usually not recommended for AGM batteries. Be cautious about ever doing that or else get specific procedure for it from the maker. Otherwise your Absorb Voltage (not listed as such) is 14.4 * 2 = 28.8 Volts. The Float Voltage range is a matter of "inactive to active" batteries; use the lower number if they are standby for back-up power and the higher number if off-grid supplying loads every day.

One of the reasons why FLA's are better; you can check the SG with a hydrometer and know if the batteries are actually charged or if you need to adjust the Voltage, current, or time up/down.

The make of charge controller is not relevant unless it limits the choices. Classics have no such limitations. The RTS should take care of itself for temperature compensation, but the range should be limited (I forget what they call it; reduces the amount of change in V per degree so they won't receive too high Voltage in cold temps).

Vic

Re: What charge specs should I set the Classic 150 to for these batteries?

T AZ,

Well, technically, the Classic (and most other Solar CCs) does/do not have a Bulk voltage setting.

There is a Limit setting in the Classic Charge menu to allow setting both the Max and Min excursions (of compensation).

The Classic appears to Default Temp Comp coefficient to -- 4.5 or -- 5mV per cell, IIRC. This is quite standard for Flooded batteries, but for Sealed batteries a smaller value seems more common.

However, it is up to the manufacturer of the exact batteries that you have to SPECIFY just what is this coefficient, and any limits on charge voltage (including under temperature compensation for temperature changes).

Opinions, Try contacting the battery manufacturer or the distributor. Vic

zoneblue

Re: What charge specs should I set the Classic 150 to for these batteries?

Your quandary is common for AGM batterys not specifically designed for heavy cycling or RE use. Dodgy documentation, and your left guessing. The plate composition does give you a place to start if thats all you can get. PNjunction has written at length about charge setpoints for lead calcium and thin plate pure lead. Most i think will be lead calcium. Theres a wide range of documented setpoints for these and theres no real way to know if you got it right, except 7 years down the track.

My batterys have low documented setpoints, and i have increased them some, based on educated guesses. What i have learned is that theres three things that will kill AGMs. Sulphation, positive grid corosion, and catylyst failure/dryout. The last is possibly teh easiest to avoid if you are careful, but the first two run at opposite ends of a undercharge/overcharge spectrum. PNJs view is that it is critical that the bank be *fully* charged regularly. Missing by 1%, will mean a spiral of sulphation related degredation. Hence my approach is to err on the high side. Positive grid corosion also increases more rapidly at lower float voltages than higher voltages.

One way to work out the float voltage is to fully charge the bank. Let it sit unloaded for 6hrs. Get the rest voltage with a 0.1% DMM. Add 70mV per cell, and thats your float setpoint. See graph here: http://forum.solar-electric.com/showthread.php?22626-AGM-still-makes-more-sense-than-Lithium&p=194215#post194215

You can use the classic to reduce grid corosion by using days between bulk. This works great in the summer months. Then when you do absorb, do it early in the day using WBjr end amps to 0.5% C20, then get a good long float in afterwards. If you do that im less sure that the exact absorb setpoint is as important. With WbJr, the higher the setpoint the quicker it will absorb. Which is better high and short or low and long? Who knows...

PNjunction

Re: What charge specs should I set the Classic 150 to for these batteries?

Those are pretty skimpy specs. They leave it to you to figure out what cycle service and EQ is - especially for AGM's that don't take kindly to what WE think is an EQ relative to an FLA.

What I'd do is treat it like an East-Penn / Deka. For normal cyclic use, set the absorb to 14.4v (temperature compensated of course). Here, an EQ may be considered a LIGHT raising of the absorb voltage, like 14.6v or so. Normally I wouldn't use it, but some inexpensive controllers that have a so-called EQ that activates every 28 days or so, might only be doing that at 0.2v above your normal absorb setting. This wouldn't hurt this battery. However, just watch out for "FLA" type EQ's, that go up to 15.5v or so - now THAT would be bad. The specs for absorb provide a little leeway between 14.4 and 15v, so I would play it conservative, or perhaps just simplify by setting bulk=absorb=float to 14.4v and call it a day for solar with an agm.

By setting bulk=absorb=float to 14.4v *with an agm* means that there is a better chance your agm's will get the best charge it can before the sun goes down and you discharge anyway. Some have been afraid to do this, but when we lose the sun, the long-term effect of a consistent 14.4v is negligible in cycle service. I definitely wouldn't do this with an ac-charger, but solar cyclic duty - by all means!

Unfortunately, manufacturers sometimes play fast and loose with the terminology that most of us are used to. boost/bulk/absorb/eq can mean different things among manufacturers so you have to read carefully and apply a bit of prior knowledge.

westbranch

Re: What charge specs should I set the Classic 150 to for these batteries?

Here is a link to some "light'" reading on batteries, enjoy...http://www.cdtechno.com/pdf/ref/41_2128_0212.pdf