Recommendation for New Batteries?

System2

Re: Recommendation for New Batteries?

Jim/Crewzer,
I have a freedom 20 charging the batteries if there is no sun. Now that we are getting snow and sun  the panels start to charge already charged batteries. If I'm at the boat I can turn off the charger. If I'm not there the mx60 goes to absorb not float. Today I figured out that I could set the absorb timer to min 000 and max 000 hoping this will help. Also set the absorb end amps to 7 A (1% of 700).
Can you tell me how you set your "temp comp limit" which you have at lo = 14v, hi = 15v.
I have absorb at 14.3 and float at 13.4 and a bts in place. My freedom charger was flashing an error for too high a voltage the other day.
Can you tell me what the voltage offset represents and how to set it ?
I don't seem to have auto EQ on my MX60. The manual says you have to manually start equalization.
How do you disable it ?
Is it possible I have an older or newer model MX60 so I don't have these chooses ?
THanks for your help,
Tp

crewzer

Re: Recommendation for New Batteries?

Tp,

You’re going love this. The MX-60 display reads “Absorbing” when it’s charging the batteries and is in ABSORB mode. However, it reads “Absorb” when there’s an external charging source charging the batteries at or above the MX-60’s ABSORB setting. :-o I’m going to have to work with my pals at OutBack to improve that li’l bit of corn-fuzion. :roll:

The voltage offset is set in the OPTIMZATION menu -> Vbatt Calibration. This feature provides for you to slightly vary the charger’s output voltage a bit above or below the display reading. The “benefit” is that you can include an offset to overcome losses in cabling or to even manually spec a fixed temperature compensation voltage.

For example (and ignoring automatic temperature compensation adjustments for the moment), if you set your ABSORB voltage at 14.4 V and there’s a 0.2 V loss in the cabling to the batteries, the voltage at the battery would be 14.2 V. However, if you add a 0.2 V offset, the reading at the battery should be 14.4 V and match your ABSORB setting and the display reading.

I don’t like this feature very much as the voltage drop in the cabling, breakers, fuses and/or shunt will vary depending on charge current. I hope the next generation MX-60 includes a battery sense feature that will automatically adjust the controller’s output voltage to compensate for the actual voltage drop in the charging cables.

My MX-60’s serial number is 03970, but I upgraded to the latest software revision (V 4.15.5.4) a few months ago (read about installing the upgrade here). It’s this s/w version included in controllers with s/n 5500 and up that includes the temp comp limits and the auto EQ function. You can read about these new features in the latest MX-60 user’s manual.

HTH,
Jim / crewzer

System2

Re: Recommendation for New Batteries?

Jim/Crewzer
I know I won't be changing the circuit board in my mx60 anytime soon.
As long as my batteries aren't too cold and I don't push the EQ botton I think I'll be ok.
When I go to the optimize screen with default settings what should I expect to see ?
Question? If the Freedom has the batteries in the float stage and the snow melts off slowly will the MX60 just dump current ?
Many thanks as always,
Tp

halfcrazy

Re: Recommendation for New Batteries?

crewzer was it very difficult to change the board in the mx60 i have to do one for a friend of mine. outback is a good company when it comes to that stuff just sent me a board to update my software no charge how do you beet that?

crewzer

Re: Recommendation for New Batteries?

Tp,

When I go to the optimize screen with default settings what should I expect to see ?

Assuming your MX-60 s/n is >1999 and <5500, I think your unit is covered by User Manual Rev. 5.0. The OPTIMIZATION menu covers 7 pages in that manual… I’m not sure about the defaults, but my starting preferences would be as follows:

Snooze Mode: < Lowcutoff
Park Mpp% (Voc): 85%
Mpp Range Limit % Voc: Min ½, Max 90%
Sweep Interval: 6 minutes (10 X per hour)
Vbatt Calibration: 0 V
Low Cutoff Amps: .8 A
MPPT Mode: Auto sweep, and non-GT if you’re not networked to an OutBack inverter
Absorb Time Limits: 30 min MIN and 2 hrs MAX

Question? If the Freedom has the batteries in the float stage and the snow melts off slowly will the MX60 just dump current ?

If the charger has the batteries at float at the beginning of a day (~ sunrise), the MX-60 will attempt an MPPT charging cycle. As soon as the batteries reach the temperature-compensated ABSORB setpoint, the MX-60 will switch to ABSORBING and continue in Absorb mode in accordance with the Absorb Time Limits settings and the internal charge timer. It’ll then drop back to Float mode and wait for a new day to start. (I think I got that right…).

I believe the MX-60 controls output current by duty-cycling the input from the PV array. When the input transistors are OFF, the array voltage approaches Voc, and there's virtually no current flowing from the array during that interval. It's this combination of switching the input transistors ON and OFF that limits current and causes the input voltage reading to read a bit higher than usual when the MX-60 is in Absorbing-, Float- or EQ mode, as the input voltage is the duty-cycle weighted average of the Voc and the real-time Vmp. (I think I got that one right as well...)

Note that the real MX-60 experts are available over on the Outback forum, and it might be worth crewzin' through our gab-fests -- er, technical discussions -- over there.

1/2,

was it very difficult to change the board in the mx60

I’ve been designing, building and modifying electrical- and mechanical stuff for a long time. Some of it has even worked! I think the MX-60 board change was fairly straightforward. I completely removed my controller from my system and, with my wife's permission , did the upgrade on my kitchen island under good light. Outback sent a DVD of the procedure with my replacement board, and I watched the video twice before operating on the patient. I was especially careful to seat the new daughterboard correctly into its socket. Amazingly, there were no spare parts or hardware left over -- and, no smoke! :roll:

HTH,
Jim / crewzer

System2

Re: Recommendation for New Batteries?

Jim/Crewzer
If it is ok with you I would like to ask more questions of you. If it is ok I will ask them over on the outback site.
Tp

crewzer

Re: Recommendation for New Batteries?

Tp,

Ask away on either forum, and I'll help when I can. The Outback forum may just prove to be an additional resource.

Regards,
Jim / crewzer

System2

Re: Recommendation for New Batteries?

Jim/Crewzer,
You wrote:
"If the charger has the batteries at float at the beginning of a day (~ sunrise), the MX-60 will attempt an MPPT charging cycle. As soon as the batteries reach the temperature-compensated ABSORB setpoint, the MX-60 will switch to ABSORBING and continue in Absorb mode in accordance with the Absorb Time Limits settings and the internal charge timer. It’ll then drop back to Float mode and wait for a new day to start." 

I put my max absorb setting to 000 so that the mx60 won't be sending 14.4 or higher, because of the bts, to the batteries for 2 hours when they are already charged.
The problem I have:
I want to use the solar as much as possible so I turn the freedom charger off. It snows or fog or just too over cast so I turn the charger on. I may not be around to turn the charger off when the panels see the sun. The freedom will always have the batteries full when the sun does come out. I don't want to over charge the batteries with a 2 hour absorb time.
I won't have this problem in the summer.
What is a man to do?
Tp

crewzer

Re: Recommendation for New Batteries?

Bill,

Thanks for the L16 AGM suggestion. I ended up buying four Deka 8A4D AGM batteries last October. I’m not sure if I knew about Discover L16 AGM batteries at that time, but, if I had, I’m sure I would have passed on them.

Each Discover L16 AGM is rated at 390 Ah at the 20 hour rate (not “with 390amp at 20 a.h. rate –“. Two of these 6 V L16 AGM batteries wired in series would be good for 12 V x 390 Ah. Two Deka (or MK) 8A4D 12 V AGM batteries wired in parallel are good for 12 V x 400 Ah. Accordingly, I find the claim that the L16 AGM battery’s 390 Ah spec to be the “ … the highest AGM on the market” to be a dubious distinction.

I also don’t see anything special about the “…1-3% discharge rate per month at 67 degrees F” spec. MK says 2% / month for their AGM batteries, and Concorde says ~1% for their AGM batteries.

In last night’s online search, I was unable to find the Discover L16 AGM battery for “about 350-400 each”. Instead, I found them for ~$470 each. Depending on which price point is chosen, four of these would cost between $1,400 and $1,880, plus shipping. At $220 each, my four 8A4D AGM batteries were $880 plus tax.

It would be helpful if you could post your price source. An alternative might be the ABS Alaskan’s L16 AGM at $278.

A major technical reason for why I went with four 12 V batteries this time is that I can configure them as a 12 V bank, a 24 V bank or a 48 V bank as I continue my experiments. I can't do that with four 6 V batteries.

The L16 does offer a couple of advantages. Flooded-cell or AGM, it can used to build a large capacity battery bank with fewer parallel strings than if using 12 V batteries, a feature that generally leads to better overall battery health and performance, as the batteries are more equitably charged and discharged. Additionally, it’s got a relatively small foot print, which might be useful for storing the batteries.

Thanks anyway,
Jim / crewzer

Brock

Re: Recommendation for New Batteries?

I also bought the Deka brand, but went with the slightly larger 8A8D at 245 amps at 12vor 245ax12v=2940 watts per battery The L16's are smaller at 390ax6v=2340w. Even the 8A4D that Bill hasis larger at 200a is acutally still holding more power at 200ax12v=2400w

crewzer

Re: Recommendation for New Batteries?

Time for an update: My AGM batteries have now been in continuous service for 4 years! I have four of these DEKA 8A4D batteries (with SAE terminals) wired in series/parallel for 24 V nominal x ~400 Ah:



They're still crankin' along... :cool:

Regards,
Jim / crewzer

bryanl

Re: Recommendation for New Batteries?

Battery type is not going to relieve the need for proper care and maintenance of a battery bank. AGM's are nice and get you about a 50% increase in life expectancy but they still need attention to proper and effective charging, sulfation inhibition, storage maintenance, and discharge levels just like any other lead acid battery.

parallel batteries are going to have an advantage over serial when it comes to Peukert - this is, in part, related to why many diesel pickups use 2 parallel batteries for starting current. Reducing current by a factor of 2 will increase available energy capacity by 15% or so for most lead acid batteries. See the smartgauge tech docs for some good rundowns on this.

With lead acid batteries, the energy density by weight falls within a narrow range so the real issues have more to do with wiring and connection considerations. Large batteries have fewer connections and simpler wiring which is generally a good thing.

crewzer

Re: Recommendation for New Batteries?

5 years old this month -- Woo Hoo!

However, things continue to change. I've started the process of removing the Brand "O" hardware and installing Brand "X".

Happy Thanksgiving, all!
Jim / crewzer

niel

Re: Recommendation for New Batteries?

happy thanksgiving stranger. i think i can speak for the rest of us in saying you've been missed here as you pop in so infrequently. hope you can find the time to post more and more often.
are you going to post some of that old stuff here on the forum?

mike95490

Re: Recommendation for New Batteries?

Welcome back Jim, many have missed you. What's the latest on planet X ?

crewzer

Re: Recommendation for New Batteries?

Thanks, guys!

I can't begin to tell you how busy I've been... but, that's a good thing! I hope to have a bit of time over the next six weeks or so so share some product info and other news.

Happy Thanksgiving!
Jim / crewzer

Vic

Re: Recommendation for New Batteries?

Hi Jim,

Nice to hear from you! Happy TG, and will stay tuned for additional info.

Take care, Vic.