Odyssey AGM and solar experience?

[inetdog]

Thanks. I had actually read that thread before. I think the hardest thing to grasp is the "C" factor. It took me a long time to sort of grasp it and I still don't fully understand it. There aren't many articles online describing the "C" factor well.

What don't you understand? Or feel uncertain about?
My biggest issue has been the notation and possible confusion there. C by itself does not tell much unless you know the hour rating that is used. The 20 hour rating can be called just that, written out in full, or symbolized as C₂₀. But if someone cannot do subscripts, that ends up being C20, and people get that confused with 20 times C.
Then when you start writing C/5 to represent the result of dividing C by 5 hours to get a current in amps, it gets really confusing.
You cannot divide amp-hours by the pure number 5 and get amps.
The C/5 rate is close to, and proportional to the current which will deliver a full charge from 0% SOC to 100% SOC in five hours.

[Sunking]

Would I be correct in adding that if I only have 1 Sun Hour in a given day to replenish X amount of watt hours I've used the night before, BUT my battery has a MAXIMUM recommended amp charge rate that is lower than what it would require me to "get back" (in that hour) what watts I used the night before, I would have to suck it up and wait for the next day to replenish the battery "safely", otherwise, I risk cutting down on the amount of future cycles.

Yes this is why you must design a system under worse case conditions.

Flooded Lead Acid batteries have a fairly narrow charge window of low of C/12 and high of about C/8. If you live in fairly sunny area with good winter isolation Sun Hours no problem. But if you live in some place like Seattle WS where winter Sun Hours is about 1 Hour you need very high charge rates. That means a way over sized solar panel, and you will have to use AGM batteries that can take the high charge rates. Read the thread I linked too in my last post and take a look at the Tuscon Seattle example. Battery size is the same, but not panel wattage.

[Sunking]

Have you read this thread yet? It will answer your questions.

[Sunking]

Sorry. I forgot the link.

http://www.power-sonic.com/images/po...0_12_Oct_2.pdf

OK they just told you exactly what I just did. You are confusing maximum with minimum. Read their two small paragraphs on Charging.

[Sunking]

So with this Powersonic, am I limited to less than .1C?

Not sure where you are getting your info from but with respect to Power Sonic there are 2 charging profiles. One of Cycle Service and one for Standby Service (Float aka Emergency). I will not address Standby or Float operation.

For cycling every day max charge current is limited to .3C. For a 20 AH battery is 7 amps. There is no low limit you just need to fully recharge.(If you only have 1 or 2 Sun Hours you wil need a very high rate.) For Cycle Service a constant current must be applied until the voltage reaches 2.45 volts per cell (14.7 volts on a 12 volt battery). After 2.45 volts a Constant voltage is maintained until the charge current tapers down to .01C. For a 20 AH battery that would be .01 x 20 = .2 amps. Once that point is reached either disconnect the charger or switch to a FLOAT Mode which is a Constant Voltage of 2.27 volts per cell.

Source Info

Regardless of battery type you have to be able to replace the energy in your alloted Sun Hours. If Sun Hours are short, sorry you need a lot of watts. That is part of the design process. If you use 100 watt hours in a day, and have a 500 watt hour battery with only 1 Sun Hour you need a lot of amps for 1 hour to get the job done like 200 watt panel.

That's all folks.

[Sunking]

Got it. Is there another battery that's around 20Ah (AGM) that would give me more room to charge higher than .4C? I don't plan on running anything A/C off of this.

To many to shake a stick at. Power Sonic has many to name one manufacture. You are talking motor cycle and E-bike very small size. Just keep one thing in mind with AGM you are border line Hybrid and will give up cycle life. Top of the line AGM is Concorde Sun Extender AGM like a 340T which is a little larger than you are looking for but should give you 1000 cycles with extremely low resistance.

[Sunking]

Look at the minimum and maximum charge rates from the battery manufacturer. I suspect .4 is max charge rate

Point of interest Odyssey does not make a Deep Cycle battery. They make Marine Hybrid batteries which will have about 400 to 500 cycle life which is not what you want from an RE battery. .4C is max charge rate. Since it is AGM you can charge as slow as you want.

The selling point of Odyssey is very low internal resistance which means they can deliver very high charge/discharge currents which is great for electric vehicles. but of no real use for RE application. Well unless you are an idiot and have a 12 volt 1000 watt inverter in your home. OK for work trucks, boats, and RV's with battery isolator working with vehicle alternator.

[thastinger]

I have a PC535 in my ATV, it has lasted for years getting shaken to hell but I seriously doubt my factory stator is capable of charging it at 7.5 amps.

[Naptown]

Look at the minimum and maximum charge rates from the battery manufacturer. I suspect .4 is max charge rate

[PNjunction]

Two new developments have surfaced that put my mind to rest when dealing with Odysseys, thanks in part indirectly to East Penn and an online statement from Odyssey to an Australian user wondering why their own chargers are not for sale there and one response was to look at CTEK, as long as the user chose one with the proper current level ....

For *optimum* life, an Odyssey needs 0.4C when deep discharged. At 50% SOC, you may get away with only 0.3C. In an automobile application, where you may only temporarily draw less then 10%, then you can get away with the current of the typical automotive alternator. Accidentally discharge it deeper and you'll want a decent charger on hand that can put out some real current.

So if you are doing anything other than SLI service, then you are going to want to have a charger that meets the 0.4C rate. Yes, you can temporarily get away with less, but *over time*, using a smaller amount of current even while charging will lead to sulfation and voids the warranty. Since the batteries are TPPL, if you have a collection of these Odyssey batteries (like I do), then a charger with much higher current capabilities is not a problem since they can take it.

Higher sulfation rates *over time* is also the reason that they specify a minimum float of 13.5V, something I never usually reached while solar, but is the main bone of contention between other charger manufacturers and backyard enthusiasts. It all depends on if you want to stay within warranty, or just buying expensive batteries sooner due to sulfation. In addition, going above or below the recommended temp-compensated float voltage leads to accellerated grid corrosion although doing nothing but just sitting with an open circuit has the highest grid corrosion rate of all.

Since I put my low-current solar-charged Odysseys on a qualified high amperage charger every week or so, I really saw no bad sulfation effects that I could detect.

My East-Penn / DEKA agm battery that I'm working on has a max current limit of 0.3C. It is NOT tppl, but lead-calcium. The good thing here is that one sentence from their tech manual states that for the longest life, one should try to charge with the largest amount possible not going over the 0.3C limit. This kind of reiterates what Odyssey is saying, although being lead-calcium, the MAX for the Deka is 0.3C. In essence, don't tickle an agm to death!

So here, yes, you can get away with less current for awhile, but it is not beneficial in the long run. If using these for solar applications (yep - they are dual-purpose hybrids, not real RE batteries) where the charge current does not meet Odyssey's minimum, (or perhaps in Deka's case being close to the max limit), then throwing them on a charger that meets these specs might be a good idea once in awhile.

[PNjunction]

Xantrex C12 vs Morningstar CC for Odyssey test

For my small battery / large panel testing, I changed charge controllers from a Morningstar Prostar 15 pwm to a small Schneider/Xantrex C12 pwm. There is a small problem however that is overcome.

The main difference here is that with the C12 I can adjust the absorb / float voltages as well as having a real temperature compensation probe on the battery, (optional, snap-in and recommended!) as opposed to the Morningstar's 14.2/14.4 absorb, and a 13.3v float with ambient temp compensation - .3v too low according to Odyssey. (real optional temp probe on morningstar you solder in yourself).

While the C12 will also do EQ (1 volt above absorb), I can guarantee it is disabled with a jumper (defaults to NO eq), but manually do it if I want to fry the Odyssey for science.

Because I'm cycling daily with limited insolation of 4 hours at best, I'm basically setting it to bulk=absorb=float at 14.5 volts. The Odyssey IUU profile wants 8 hours of absorb before dropping to float, and there's no way I'm going to get that with daily cycling. ALSO, the Xantrex will automatically drop to float after a fixed-period of only 1 hour at absorb with no way to adjust that time. So I compensated with an absorb-matching float voltage due to my restricted time period.

So far so good, and I like the flexibility of the C12. Not too happy about the self-tapping sheet metal screw on the front cover, but it isn't a showstopper. I don't use the load/lighting control options. I'll let you know if I let the smoke out.

P.S. - the sunken led on the front cover is NOT the EQ button. Don't push it in, and be careful when removing the cover for adjustments so you don't bend it. Less coffee helps when unboxing.

[PNjunction]

Got the word back fast from Enersys regarding the difference between the Odyssey and the Genesis XE - they have the same electrochemical design, so performance is the same. I take it that would also now include the Hawkers and Diehard Platinums. I suspected as much but wanted an official word.

Forgot to mention a big difference between the 1998 application manual for HEV's, and the more modern manuals which followed - the modern manuals make no mention of a fast 6-8 hour charge ability with a 15.6v stage following absorption as seen in 1998 - in fact now they prohibit voltages above 15v for any reason. Still, with my unauthorized chargers which immediately voided the modern warranty, the PC525 / 625 didn't cry in pain when they went to 15.5v after absorption for a short time. We're entering an EQ type of voltage here, so I'm being careful to pull the charge when it does happen.

[PNjunction]

0.4C only needed at 80-100% DOD!

Well - a tip of my hat to Sunking and Inetdog: You guys are making my eyes bleed researching all this stuff. For some reason, I can't get enough of it.

While I won't be building an RE solar system based around tppl batteries, the point is, it can be done - but that 0.4C minimum inrush current is a real pita for most solar users. This old application manual from Hawker in 1998, which goes into greater detail than the more recent application manuals about using tppl batteries in HEV (hybrid electric vehicles) explains it all in a way a dunderhead like me can relate to: (Hawker Genesis Electric Vehicle Application Handbook, 4th ed 1998)

http://www.evdl.org/lib/index.html

Essentially, the 0.4C minimum limit applies if you are trying to recharge a battery from deep discharge 80 to 100% DOD back to life in 6 to 8 hours using the fast-charge profile they describe for a typical fleet of HEV's!! As solar users, we don't go there - at least not intentionally or unless the system was put together with no engineering applied at all. SO, I have no problem designing a small tppl solar system around much lower minimum inrush currents - as long as all the other elements of good solar design are taken into account obviously. WARNING - this document is from 1998, and specifications (and warranty spec claims!) can change over the years.

It also explains why my Schumacher charger didn't make the vents immediately blow - but I'll leave that for another forum.

At least I'm no longer worried about the 0.4C minimum, and in fact will be using more typical 0.15 to 0.2C rates with my temporary tppl-battery solar setup since I won't discharging down to 50% DOD on a regular basis anyway and my solar insolation will meet the need - although I will hit them up with more current when I can. I will be using a line-powered charger for maintenance once in awhile however since I feel that the 14.7v is the true minimum voltage spec to meet, and my little pwm cc only limits up to 14.4v.

Had I just started with a dedicated RE agm, I'd have a few more hairs on my head. I must be crazy to think this is fun - but it is!

[inetdog]

TPPL: The pure-lead tin overcomes the shedding due to the materials being about 30% larger than the case itself, and is very tightly compressed during case fitment to make it physically harder to shed.

Since lead is not going to compress much, I have to assume that the compression is all in the fiberglass mat between the plates. It seems that that would also tend to leave less room for electrolyte, require thicker mats to start with, and possibly reduce the ionic mobility of the electrolyte. But if you can get significant compressive forces while still leaving a sufficiently open mat, then it does sound interesting.

And although this may address shedding, I can't see it similarly affecting the corrosion (redistribution of the lead) during deep charge/discharge cycles.
Waiting to hear whether the current issue of the bible adresses the TPPL design.

[Sunking]

The Odyssey manual describes the use of Total-Loss (no alternator) racing, so there is some measure of deep-cycle capability -

Do not think I would make that conclusion. Tires and engines are disposable items in racing. I would think the battery is a one-time use product.