|
| Author |
Message |
bbandeddie
Member
|
# Posted: 19 Feb 2018 06:21pm
Reply
Hey folks, new here but been lurking for a while.
We have an off-grid cottage in Muskoka which we are prepping for solar this year. Alas, this post isn’t about the cottage.
We are also seasonal fulltime RVers. Before we set out this past fall I did some electrical upgrades to improve our boondocking experience.
I replaced the dead 12V FLAs with a pair of Crown1 6V AGMs, installed a bogart Tri-metric and Bogart’s solar charge controller complete with temp sensor. I wired up a couple 100W panels as a portable panel set as I wasn’t ready to start messing around on the roof of the rv. While I was at it, I wired in the Morningstar 300W SureSine inverter. I figured this would be ample power for anything we planned to do while boondocking - Tv/DVD, Jen’s sewing machine, charge the laptop.
Problem I’m having is I can’t seem charge batteries and run the inverter together. Well, I can, but the SCC routinely causes the inverter to trip on high voltage. The inverter HV trip level is 15.5V. First time this happened it took me a couple days to figure out what was causing the trip. Then, it was because the battery temp was low enough that the temp compensated voltage was blipping up to 15.5V. The inverter doesn’t reset until voltage dips to 13.4V which it’s never going to do until charging is finished.
Now it’s warmed up, I thought We wouldn’t have the high voltage trips. Enter today. Scattered light clouds. It seems the sun moving in and out of the clouds causes a high voltage event - tripping the inverter. Temporary solution - “honey! I’m ready to sewâ€. I run out, move the panels into the shade. “Honey! I’m done sewing†run out and put the panels in the sun again. Rinse and repeat all day. Arg.
If I had put the panels in the roof I’d be SOL - no sewing until evening.
So. What to do?
Solutions present themselves:
A) remove temp compensation - at expense of battery life
B) experiment with voltage limits on the SCC, again, at expense of battery life
C) some other solution?
I’m dumbfounded that a company like morningstar with a strong reputation in SCC would design an inverter (the only one they make) with a HV trip well within operating range of the SCC.
While still annoying, a reset voltage of 14.7 or so, would have been much easier to deal with!
Or am I missing something else entirely?
Thanks
|
|
bbandeddie
Member
|
# Posted: 19 Feb 2018 06:53pm
Reply
Further notes. A windstorm today has put a high level of dust in the air. Even in a cloudless sky the resultant haze is causing wild fluctuations in voltage. Swinging as high as 16V (my SCC max voltage set point). I changed the set point to 15.4V and that has stopped the inverter trips on HV.
Okay. I’ve also refreshed my understanding of temperature compensation. 0.004V/cell/(°C from 25°C)
So, with a 12V battery array of AGM and an absorption voltage set point of 14.6V - the coldest my battery is likely to get doing our use (batteries are under the bed) is 5°C- so 6cells * .004 * 20° delta is an adjustment of .48V for a max charge current of 15.08V.
So. I’ve set my SCC max allowable current to 15.4V.
And I won’t worry about it.
Does this sound right?
|
|
Nate R
Member
|
# Posted: 20 Feb 2018 08:21am
Reply
That sounds better. Because, yeah, I don't think 15.5V is "WELL within the operating range of an SCC."  Most people aren't charging at 5C, I'd think, either. But, definitely some of us are. I looked up Crown's info, and came up with something similar to what you found later.
https://www.wholesalesolar.com/cms/crown-2crv1200-agm-2-volt-battery-specs-2243747105 .pdf
Crown themselves recommends 3mv/deg C for an AGM battery.
Crown says 27 deg is their baseline. So, if absorb is at 14.6v normally.....
.003*22 = .066 V per cell increase at 5C. So, 14.996 for 2 6V at 5C. I think 15.4 is plenty high still, and no need to worry. Maybe 15.3 would be fine. Either way, hopefully that means you're no longer triggering the SureSine!
|
|
creeky
Member
|
# Posted: 20 Feb 2018 09:27am
Reply
If the charge v is 14.6, that is what you should charge to. Set your absorb period at 14.6 by the amount of time specified in the manual.
Overcharging, ie. Too high a voltage, just boils the battery. I understand it's particularly hard on agm batteries.
Let the charge controller manage the voltage based on temp. 15v for a cold battery is fine.
Is 14.6 what crown wants for its agms? Seems high.
|
|
bbandeddie
Member
|
# Posted: 20 Feb 2018 04:17pm
Reply
So, yes, I’ve set the SCC to manage temperature compensation. Crown has a range for charge voltage that 14.6 lands within. Bogart, also recommends 14.6V on the online parameter helper for setting up their SCC - type in the battery specs and manufacturer/model details and it spits out the parameter set points.
Since lowering the voltage limit of the SCC I’ve had no more inverter trips.
Thanks for the confirmation!
|
|
Pjon
Member
|
# Posted: 23 Apr 2021 11:59pm
Reply
bbandeddie
It sounds like I am having the same issue with Morningstar 300 and Bogart Trimetric. I was wondering if you could let me know what ‘P’ settings you are using on the Monitor that will fix the tripping.
Thanks
|
|
Brettny
Member
|
# Posted: 24 Apr 2021 07:52am
Reply
It sounds like they lowered the max charging voltage and that fixed it. At 15v for any liquid filled battery your really pushing it..so lower the voltage to what the battery manufacturer says it should be.
|
|
Nate R
Member
|
# Posted: 24 Apr 2021 09:09am
Reply
15V pushing it? Not when the manufacturer recommends 14.7V for the Absorption part of the charge cycle, and it's cold out....
I have a Morningstar Prostar MPPT controller. It keeps track of my daily max voltage, and temperature compensates charging for temperature. Over 700 days, about 230 of them have seen over 15V...nearly 1/3! This is with things set to battery manufacturer's recommendations, and the battery in a shed that is close to ambient. (COLD in winter.)
Pjon, looks like you should maybe alter P8 to <15.5V?
2.2.2. Advanced Programmable Parameters-accessible only when Program P7 is set to L3 or L4. Default
values shown below are automatically installed when switching from L4 or L3 into L2 or L1.
P8: Maximum voltage limit: SC-2030 solar charger only: this limits the maximum charging voltage.
I think this is one of the biggest downfalls of the ProSine....15.5V max DOES seem a tad low. 16.0 maybe or 16.5, sure.
|
|
|
Pjon
Member
|
# Posted: 24 Apr 2021 01:00pm
Reply
Ok. Thanks. I’m fairly new at this. I will try setting P8 to 15.4v. I even messaged the guy from Bogart but he made it sound like setting P8 was a hard limit, and it would shut down at the max voltage set. If the panels give more than 15.4, will it shut down the controller?? Or will it still charge the batteries while it is peaking at that max limit? Any help is appreciated. Thanks. I guess I can try it and use a volt meter at the batteries while this is occurring, to see if it’s still charging.
|
|
|
