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Open Roads Forum  >  Tech Issues

 > question on interpreting MPPT controller display

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pianotuna

Regina, SK, Canada

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Posted: 09/06/17 12:04am Link  |  Quote  |  Print  |  Notify Moderator

Hi outwestbound,

Another thing that happens with the starved acid AGM design is that the cells literally can not get to 100% discharge--they can't because they run out of acid before the plates run out of active material. If there were a way to add more acid they could be discharged more.

My own personal view is that the lack of acid works to protect the plates and may slow down the shaling that always occurs on the positive plates.

That is, I think, also why a 100 lb flooded jar will have slightly more amp-hour capacity than an AGM of exactly the same weight.

The surplus acid format that I use does not offer that protection--so I need to be careful to not take the jars down below 50% state of charge.


Regards, Don
Full Time in a 28 foot Class C, 256 watts solar, 556 amp hours of AGM in two battery banks 12 volt batteries, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

pianotuna

Regina, SK, Canada

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Posted: 09/06/17 12:23am Link  |  Quote  |  Print  |  Notify Moderator

Hi outwestbound,

To adjust the Magnum charging rate, touch favs, then rotate the dial until F3 appears. That allows you to select the number of amps that the Magnum will draw from shore power (lowest setting is a mere 5 amps) or from a generator (in my case 24 amps from the Yamaha 2800 sIEB).

I do use this feature to limit my demand to 80% (12 amps for a 15 amp, 24 for 30, and 40 for a 50 amp shore power).

If you are in load support mode this will trigger it sooner. If there is poor voltage then limiting the amps can "force" the Magnum to do voltage support and not just load support. I DO NOT RECOMMEND THIS.

Voltage support is best done with an autoformer.

BFL13

Victoria, BC

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Posted: 09/06/17 07:59am Link  |  Quote  |  Print  |  Notify Moderator

PT, I think the OP wants to go away and think some. BTW,

"Flooded jars start to taper on charging at 85% SOC" is not correct. You have forgotten my ugly graph! [emoticon]

The SOC when Absorption starts is a variable. A higher charging rate (amps/bank AH) means battery voltage will rise quicker and bulk ends at a lower SOC--could be 65% or anything really. With a lower charging rate Bulk might not end until 90% or so SOC.

Mex likes a high enough charging rate that battery voltage spikes immediately to near Vabs and amps taper from the start. That being the fastest recharge and so the least gen time.

However, the max charging rate can be limited by the battery spec, say 27% in one case. No matter, anything over 30% has little time advantage over 30%'s time since the battery just can't do its chemical change any faster. (except Lifeline AGMs somehow)


2003 Chev 2500HD Gas, 2003 Komfort 26FS 5er,
1981 Frontier 11ft Truck Camper
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Bryan

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Posted: 09/06/17 09:15am Link  |  Quote  |  Print  |  Notify Moderator

The IUI profile is 14.7 till .02C then 13.65v float/taper.

The IUU profile is 14.7 till .02C then maintain .02C till dv/dt doen't change/hour up to 16.2v, .02C ~16A

I don't see 14.9v for 2 hrs/30days much of a top charge after days of 14.4v max.
Might see higher than .02C doing this but it is very limited in time/voltage. Likely still undercharged.

BFL13

Victoria, BC

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Posted: 09/06/17 12:51pm Link  |  Quote  |  Print  |  Notify Moderator

The OP should "recondition" his AGMs ASAP to make up for undercharging them so far, and then get on track.

outwestbound

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Posted: 09/06/17 01:32pm Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

The OP should "recondition" his AGMs ASAP to make up for undercharging them so far, and then get on track.


What do I do to recondition them?


2011 F350 6.7L, 4WD, DRW, 8' bed, Reese Elite 25K
2011 Carri-Lite 36XTRM5, MOR/ryde IS, 8K disc brakes, 17.5" wheels/G114s
Solar: 960 watts, 3,000 hybrid inverter, 830 AH bank, 2 controllers
IT: weboost 4G-X, WiFi Ranger Elite Pack

BFL13

Victoria, BC

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Posted: 09/06/17 02:04pm Link  |  Quote  |  Print  |  Notify Moderator

outwestbound wrote:

BFL13 wrote:

The OP should "recondition" his AGMs ASAP to make up for undercharging them so far, and then get on track.


What do I do to recondition them?


From that earlier link--
"REFRESH CHARGE
If Fullriver batteries are properly charged they
should never require an equalizing charge. If
they were not properly charged and there is a
decrease in capacity, recharge the batteries and
make sure they complete the entire charge cycle.

It appears from that, that you don't do an overcharge, but do a deep cycle. Draw them down to say 60% SOC at say their 20 hr rate (doing a pair of 6s at a time) 415/20 = 20.75 amps

Then recharge fully per instructions in that link (figure 1)

However, usually a recondition means a slight overcharge for a length of time, but I don't know how much for how long is good with AGMs. Fullriver seems to have its own way as above.

IMO, call their tech support and try to pin them down on what exactly to do in your situation. (please pass along what they say) I suppose the Magnum charger can be adjusted to do anything Fullriver wants, but if it can't, that's another issue. There are adjustable voltage chargers that can if the Magnum's adjustments aren't suitable.

outwestbound

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Posted: 09/06/17 08:02pm Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

outwestbound wrote:

BFL13 wrote:

The OP should "recondition" his AGMs ASAP to make up for undercharging them so far, and then get on track.


What do I do to recondition them?


From that earlier link--
"REFRESH CHARGE
If Fullriver batteries are properly charged they
should never require an equalizing charge. If
they were not properly charged and there is a
decrease in capacity, recharge the batteries and
make sure they complete the entire charge cycle.

It appears from that, that you don't do an overcharge, but do a deep cycle. Draw them down to say 60% SOC at say their 20 hr rate (doing a pair of 6s at a time) 415/20 = 20.75 amps

Then recharge fully per instructions in that link (figure 1)

However, usually a recondition means a slight overcharge for a length of time, but I don't know how much for how long is good with AGMs. Fullriver seems to have its own way as above.

IMO, call their tech support and try to pin them down on what exactly to do in your situation. (please pass along what they say) I suppose the Magnum charger can be adjusted to do anything Fullriver wants, but if it can't, that's another issue. There are adjustable voltage chargers that can if the Magnum's adjustments aren't suitable.


Thank so much for all your help. I'll call Fullriver. I have a lot of reading to do to get caught up. The bank was installed 5/1/16. I was so busy working, I didn't use the solar until 5/1/17. During that first year of ownership, I was in parks mostly on 50, but also on some 30 amp pedestals, or it was winterized. From 9/1/16 to 4/30/17, the camper was winterized but plugged into a 15amp exterior plug at a home. I set the magnum shore setting down to 15 during this period of winterization, and the magnum's max charge rate was at it's default setting of 80%. When I checked it periodically over the winter, it as "floating".

Since 5/1/17, I've been boondocking a good bit, but also in parks also. Probably 50/50 that I've been on pedestals in which the magnum would have brought them up to full charge.

While I'm sure I didn't charge them fully while boondocking, it was close, because I charged them until the idiot SOC percent meter said 100%, but also when the I/O got to zero. The single meter reading wasn't accurate due to load.

I'm hoping they aren't damaged. They don't seem to be, but I'm not competent to know the difference.

I need to re-assess exactly what I have and how the settings are, but most importantly, correct my incompetence in operating the system. If I'm convinced I'm doing the best I can, and getting a 3.6 onan for $3,500 is the only thing that makes good sense, I'll do that. I am not going to set up 2 Hondas, if that's what it takes to get these fullrivers to 100%, and only one Honda will not achieve the amps required, cuz it's a 13.3 output, based on what I'm understanding in this thread.

Getting educated about how to operate the system will come in the next 30 days. For now, I need to learn more so I may ask intelligent questions.

Thanks again.

BFL13

Victoria, BC

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Posted: 09/06/17 08:38pm Link  |  Quote  |  Print  |  Notify Moderator

Batteries are a consumable item. They are not that expensive per year over say 5 years. No way spend thousands to make the batteries last a couple years longer than they would last otherwise. Save peanuts a month. Phooey, just get new batteries as needed.

You can just recharge two at a time with the gear you have now, no sweat. 415AH x 20 = 83 amps. The Honda 2000 can do that on a power-factor corrected charger. You don't have to do all four at the same time.

outwestbound

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Posted: 09/12/17 06:56pm Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

Hi outwestbound,

To adjust the Magnum charging rate, touch favs, then rotate the dial until F3 appears. That allows you to select the number of amps that the Magnum will draw from shore power (lowest setting is a mere 5 amps) or from a generator (in my case 24 amps from the Yamaha 2800 sIEB).

I do use this feature to limit my demand to 80% (12 amps for a 15 amp, 24 for 30, and 40 for a 50 amp shore power).

If you are in load support mode this will trigger it sooner. If there is poor voltage then limiting the amps can "force" the Magnum to do voltage support and not just load support. I DO NOT RECOMMEND THIS.

Voltage support is best done with an autoformer.


Don't have "favs" on RC-50 display, but I have shore power, which allows increments of 5, so 10 and 15amps for the Honda 2000. I've got it on 15amps. Also, the "max charge" rate on the magnum was set at 80%, so I moved that down to 70%. The Honda wasn't tripping at a shore of 15 setting, but I'm thinking setting the max rate down to 70% will be a little more comfortable for the Honda.

I regret allowing these BZ controllers to be used, because the set points are not programmable and the AGM profile settings seem too low at bulk 14.00 for 2 hours, absorption at 14.00 and float at 13.7. Plus, they have no capacity to add a display, which was explained to me, but that now I regret accepting.

I'm not naming names, but I can tell you that the installation was done very well by a solar company with 25 years in the business, but these controllers are a weak link, it seems to me.

Because my system is already built for stacked controllers, I'm thinking of getting a couple Victron SmartSolar 100/50 MPPT controllers from AM Solar, which would allow me to monitor them via Bluetooth/ iPhone app. They fit in the same spaces vacated by the BZs, so no re-work expense. The Victron sizing tool indicates that my 3 panel, serial arrays are easily accommodated by each controller, but with no ability to add panels. If I add panels in the future, I'll just upsize a controller with a Morningstar controller. With 960 watts now and having more power than I could ever use it seems, getting bigger may be unlikely.

The Victrons have a form factor fitting the space, plus they have no fans, which I like because I'd hear them in my particular set up. After 30% credit, the swap is about $525 (less salvage value on the BZs, if any) to match the voltage to my batteries + have monitoring capability.

Oh well. Live and learn :-)

* This post was edited 09/12/17 09:49pm by outwestbound *

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