Charging from generator, WhizBang does not report correct SOC

2twisty · November 2014

I have a Midnite Classic 150 and a Whizbang Jr. When charging from solar, it seems to report the correct SOC in the batteries. WHen I charge from my generator, despite the fact that the current from the charger also goes through the shunt, I don't seem to get a proper SOC readings.

The WbJr shows that the charge is done since the batteries aren't taking amperage anymore. I let it run yesterday until it showed only 5A going into the batteries (832Ah@12v bank) and my End Amps setting is 9 on the CC.

Is this normal to have the CC say you are at only 80%SOC when you can be certain that based on the amps going in that it is fully charged? Is there some way to make the CC reset the SOC level in the charge controller?

This is normally not a problem out here in the West Texas desert, but we are having some rather abnormal weather this month. We have had 3 consecutive days of overcast that I have had to run the generator to keep the batteries up. Since my SOC is not being reflected by the Classic properly, I am concerned that I may be running batteries lower than I want to.

Once I get to "end amps" again today, I'll measure SG in a few cells to make sure that I'm right that the batteries are truly fully charged....assuming that I'm right, what can I do to get the CC to measure the SOC correctly?

Photowhit · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

boB and Robin stop by over here often, but Midnite has their own forum.

2twisty · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

I'm just a lurker over there -- I was hoping that boB or Robin would see this here.

westbranch · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

Got any pics of your wiring around the shunt/WBjr ?

zoneblue · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

There are two possible causes. One you have the generator connected to the battery side of the shunt... or, youve encountered a SOC anomoly most often caused by a controller reboot during the middle of the day. Wait for it to float again, then try to reproduce it.

2twisty · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

charger is definitely NOT on the battery side of the shunt.

I waited until the WbJr said it was reading 7A and checked SG (this was under a small load -- i just popped a cap off and measured real quick) and I got 1240. So I wasn't FULLY charged as I had expected.

I cut the power to my charger for a few minutes and turned it back on and now its putting almost 20A in. So it seems that my PowerMAX 100A 12v charger has a fixed length bulk charge cycle since a "reboot" made it start pumping the juice in again.

The CC has had a mid-day reboot since the last float. It is also set to reboot at midnight as well.

As for reproducing it after the next float, well, you're stating the exact problem. I havent' been to float in almost 4 days now because of overcast. So, I will likely be able to produce it again after the next float when I have more days of only being able to charge from the generator.

we shall see, I guess. I'll let the genny run for a while more and when it gets to End Amps again, I will check SG again. Hopefully I can get the SG up to the right level and then I'll know that there's a problem with how the WbJr is measuring.

Photowhit · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

I would just be shooting in the dark, I haven't even set up my Whiz bang Jr for my Classics! and I was/am their biggest cheerleader!

There may be a switch or setting hardware or software to switch where it measures the end amps, at the CC shunt onboard or at the Whiz Bang Jr... Just a guess, I suspect there has to be a switch/setting to do this.

2twisty · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

I am set to use the WbJr for End Amps. One of the best reasons to use a WbJr, IMO -- it just seems like its not working.

Hopefully I will get enough sun soon to get to float and see if this recurs. It is annoying that a mid-day reboot of the CC can cause this. It would be nice if there was an override in the CC to tell it to reset SOC manually for just this occurrence.

westbranch · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

apart from the reboot, it seems that there is something amiss with either the time spent in Absorb or the Absorb Voltage.
These are the 2 factors that get you , properly, to Float.
What does the manuf. require?
What are your settings, and if you have reached a full charge (SG verified) when did it happen, spring , summer fall,...??

zoneblue · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

Im not really sure whether theres something weiard going on there becasue i can quite picture what your doing. I agree with WB. If you havent floated for some days then thats a priority to get the SOC up. Use the gen early in the day to do the bulk, and the first bit of absorb, then let the solar complete it.

Im not sure WBJr SOC has much if anything to do with this. SOC isnt per se used for anything in the classic. For EA to work, the condition is that absorb voltage must held, AND battery amps drop below the EA setting for 90 sec, AND the max absorb time hasnt been reached. If your system is going to float (and assuming you dont have max absorb time set too low, becasue that rules), and having your SGs not at target, then either your EA is set too high, or your bank is sulphated, which messes with EA.

The trick to setting EA, is to plot the charge curve one day, locate the knee, add about 0.75A and set that as your EA figure. Be sure that EA says 'Use shunt.'

Lastly, as i said if you reboot the classic or it reboots by itself during the day the SOC will revert to the last known midnight value. This can create some occasions of odd readings, and is just something you have to watch out for until bob comes up with a fix for this. If your bank is not floating each day then the SOC errors could be a bigger deal.

Edit:
>So it seems that my PowerMAX 100A 12v charger has a fixed length bulk charge cycle since a "reboot" made it start pumping the juice in again.

Thats pretty unlikely. Voltage threshold is system used since time immemorial. It may just be that two chargers have quite different setpoints. One is floating prior to the other.

2twisty · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

Well, I should get to float today. Looks like the crazy overcast may not be happening today. I just woke up and started the generator. I'll let it do the bulk charge today and then let the solar complete it.

Batteries are new (first use in August) so not likely sulfated. CC is set to use the wb for end amps. My battery charger that is generator powered is not adjustable, so I can't change the absorb time or voltage per manufacturer specs. The charge controller IS set per the battery specs. However, since the last several days I've only been harvesting peanuts from the panels, there was never enough going in to get them to float. I tickled absorb a few times with the aid of the generator when we had a few minutes of sun.

Let's hope that today we can make it through. I'll let you know what my SG reads when I can get to float.

zoneblue · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

If you are north (and esp well north) of the equator then yep youve got the winter ahead, and its a good time to get a routine established. Winter genset use is a fact of life in northern latitudes. According to your sig, you could do with one extra pair of panels. That would bring your charge rate up to 0.1C and give you a much better shot at solar recharge in a single (sunny) day. With marginal weather capitalising on the occasional clearances works to a point.

Whats your overnite DOD & daily load Wh typically?

CDN_VT · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

2twisty wrote: »

Well, My battery charger that is generator powered is not adjustable, so I can't change the absorb time or voltage per manufacturer specs.

If you have have a good DVM that has Hz on the unit , run the gen and check that the shunt is not seeing an AC ripple from poor rectifying from the gen-set .. THIS CAN reak havoc on micro computer circuits. when the gen-set is off should be none. I use a lab Pico scope to see this. I would use an Iota charger instead & adjust the voltage output for what you like.

VT

Edit add , the above post could be for the WBJr misreading post you made

VT

Alaska Man · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

When I had this problem it was because I had landed the negative lead from the CC to the battery bank not the shunt. Everything inverter/charger/controller/wind genny, etc should be landed on the shunt and only the shunt. One wire goes to the battery bank on the negative side of the shunt.

Vic · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

twisty,

The largest issue (to me) in trying to use an AH counting system to read true SOC, is that the battery efficiency changes, depending the charge voltage and time spent at that voltage. For example, your system might spend all day in Bulk, and have returned enough AH to have fully charged the battery, after applying the efficiency factor that you have entered, but, the battery would not be fully charged, as the Absorption stage was missed, and so on.

Having the Classic CC transition to Float does reset the SOC to 100%. Looks like it has been days since the Classic has gone to Float. Each of these intervening days since Float, allows the SOC to drift farther and farther from a true value. This is not a limitation of the Classic or the WB, it is just the nature of any Battery Monitor function.

It is very difficult to determine the efficiency of the battery when charging, and the charge rate, and temperature also have an effect.

A Battery Monitor is just a ROUGH APPROXIMATION of the true SOC, and, IMO, should only be used as such.

You have flooded batteries, as you mentioned, and thank goodness, because you can use the best tool for the SOC determination job -- your Hydrometer.

The Classic/WBjr team is a great setup. To me, the ability of the WB to end Absorb based on actual battery charge current is the a huge benefit. The Approximation of SOC that it offers is nice, but is just approximate.

Opinions, Hope you get some sun, Vic

boB · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

Just saw this...
The WB Jr. should work fine with that generator.

The only automatic thing the Classic does to change to 100% SOC is when the Classic automatically goes from Absorb to Float.
This assumes that the Absorb time or ending amps are correct but to be sure, a few hours should be good.

After this transition from Absorb to Float, it's only the amp-hours in and out of the battery that define the SOC %.

Absorb to Float is not required to go from a low battery to a full battery but is a great time to reset the SOC to 100%...
Some do not Absorb every day so that the batteries can have a longer life. Absorbing is usually necessary once in a while to
stop sulfation. "Anti Sulfation Stage" so that your batteries are A.S.S full.

So, if you know that your batteries are at 100% SOC you can force the Classic to this from the MNGP and the WB Jr.
menu. If I remember correctly, go to the WB Jr. status screen and press the soft-left key (MORE). Then HOLD down
the LEFT-ARROW key and while holding that down, press and hold the ENTER key for a second or so. If the SOC %
says 100 or the Amp-Hours left come back up, it worked. You MAY have to press the MORE key twice ? I don't have
things in front of me right now. I'll check back in a day to make sure I got that right.

Thanks,
boB

2twisty · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

Thanks. boB. I did manage to get to float the next day and it has been working properly (seemingly) since.

I guess it's just the nature of the beast. I have 5 more panels coming tomorrow, and in the next couple months I plan to double my battery bank. Don't worry. I'm going to 48V in this process, so I will only wind up with 2 parallel strings and 416AH of battery when I'm done. When the panels arrive, I will be installing the VFX3648 that I got from NAWS and switching from 12V to 48V.

Once that occurs, I should have no trouble getting to float, even in the winter. As for latitude, I'm near El Paso, TX, so I don't have nearly the issues that those crazy Alaska peeps do, lol.

Alaska Man · November 2014

Re: Charging from generator, WhizBang does not report correct SOC

2twisty great blog you have there.

There is a community of people much like yourself on-line. In fact one of them lives in Tyler TX. We all were on a forum once called Homestead.org, but we are now on Facebook. You should check it out, Homestead Diaspora it's for people that have left the "Rat Race" for a simpler life. It's kind of "left" leaning if that kind of thing bothers you, but there are plenty of conservatives on there too. Like minded folks that have done or are doing the life style changes you are doing.

Charging from generator, WhizBang does not report correct SOC

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