Navitron Renewable Energy and Sustainability Forum

Energy/Electricity Storage and Use/Grid Connection => Off-Grid, Batteries & Inverters => Topic started by: Pord on January 23, 2019, 01:25:53 PM



Title: Battery monitor says 100% charged, SG says not
Post by: Pord on January 23, 2019, 01:25:53 PM
We've been running the following 24v system for about 7 months:

4 x 250w 24v pv panels, each pair connected first in series then the pairs connected in parallel
Victron mppt 100/50 controller
Victron BMV700 monitor
Victron inverter
4 x 6v Crown CR220 FLAs

The controller settings include 29.6v absorption, 27.2v float, 31v equalisation.

I've recently compared the battery charge via the BMV700 and battery SG and while the monitor shows 100%, the SG is around 1255-1265 (that's without temp compensation for the current 4degC), so it appears the batteries aren't fully charging.

Last week I did an EQ charge and it only pushed the SG up a little. I tried another EQ today as there's plenty sun, but it kept switching EQ off and back to standard charge status, apparently whenever the input wattage hit around 300w with the panel voltage around 70v.

Do I need to change my controller settings?


Title: Re: Battery monitor says 100% charged, SG says not
Post by: billi on January 23, 2019, 01:52:34 PM
Quote
Do I need to change my controller settings?

No  ;D take a brake to the canary islands  and come back  and your batterymonitor ,will still tell you 100 % full  but actually  its 120% full ....

Not sure if the new versions of Victrons batterymonitors are  taking  that Peukert   thing ( never understood it completely)  more into account , but my basic  investigation was that my chargecontrollers kept on charging , while the monitor said 100%    and after i(we = sun and me) managed to  put much more AH into the batteries  than 100%   i told the batterymonitor that 120 % -is now for controllers limited brain - a full charged 100% battery


Hope that was not too confusing now  :norfolk


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Pord on January 23, 2019, 04:28:34 PM
Thanks Billi.

Yes, it does have a Peukert option but I don't use it. It's not so much the monitor reading I'm concerned about, more the fact that the batteries are apparently not being fully charged, even when there's plenty solar gain available (like this morning). I'm therefore wondering if my controller settings are somehow throttling power into the batteries and if so, how to safely adjust the settings to allow them to become fully charged.


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Scruff on January 24, 2019, 03:12:31 AM
The monitor is not as accurate as the specific gravity.
I understand peukert's exponent and find with discharge levels under C10 not using it is most accurate.

You need to either change the charge controller settings or the charge controller.

My MorningStars charge to between 105% to 120% and specific gravity 1.275 per cell at  2.47V p/c plus remote temperature compensation depending on how hard I am on the battery.

I have found my Victron appliances to consider 1.265 to be fully charged.



Title: Re: Battery monitor says 100% charged, SG says not
Post by: Scruff on January 24, 2019, 03:19:54 AM
(https://www.boards.ie/vbulletin/attachment.php?attachmentid=468954&stc=1&d=1545915933)

If you look closely in this head to head you'll see Victron is pushing low float while MorningStar is in Bulk. Speaks Volumes.

Here's a close up what happens most days.

(https://www.boards.ie/vbulletin/attachment.php?attachmentid=468959&stc=1&d=1545916353)

Victron has a lie in while MorningStar gets to work.

(https://www.boards.ie/vbulletin/attachment.php?attachmentid=468960&stc=1&d=1545916366)


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Scruff on January 24, 2019, 03:24:49 AM
(https://www.boards.ie/vbulletin/attachment.php?attachmentid=442444&stc=1&d=1519255210)


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Nickel2 on January 24, 2019, 08:39:22 AM
Some home brewers have remote monitoring/blue-tooth digital hydrometers that measure 1.000 to 1.300. Would one of those be suitable?


Title: Re: Battery monitor says 100% charged, SG says not
Post by: oliver90owner on January 24, 2019, 08:49:48 AM
Not sure that any home brewer would need an SG anywhere near as high as 1.3!  1.15 would make a high-ish alcohol wine - the brewers amongst us would settle for about 1.07 as a high norm, and 1.1 for the brewers of really strong beer.

But the analogy is close enough, I suppose. :)


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Pord on January 24, 2019, 10:10:12 AM
Thanks Scruff. I was planning to add the facility to use our portable 1.9kw genny to top up the batteries, but if I can tweak the controller to increase the charge via the panels then it shouldn't be necessary (our useage is very low).

Am I worrying unnecessarily? Our fully charged Crowns should be at 1.275 at 25degC. At our current 4degC the 1.255-1.265 currently reading across the 12 cells would adjust to (I think) approx 1.240-1.250.

If we can work with the existing controller for now, which settings would you suggest changing?

Any idea why the controller wouldn't stay in EQ mode? And would an EQ charge actually help fully charge the entire bank?

Nickel2, just to be clear, it's not measuring the battery charge per se that I'm primarily struggling with, it's how to get the solar controller to increase the charge to the batteries.



Title: Re: Battery monitor says 100% charged, SG says not
Post by: Scruff on January 24, 2019, 11:13:47 AM
Hi Pord, you are working against two very difficult problems to overcome.
The first: Victron don't think external temp sensing is required on their small controllers.

(https://www.boards.ie/vbulletin/attachment.php?attachmentid=468910&stc=1&d=1545864890)

This equates to 800mV too low from what it should do and what it does do.
They take a one time reading from the internal sensor and then it assumes it's unwaivering as the controller temp rises and makes it redundant.
It's included as a feature to place them beside their competitors however it does not work.

The second is Victron are AGM biased for mostly idle systems like posh boats and lawsuit mitigation. They spend more on marketing than product R&D.
I've given up trying to charge batteries with them. I just use mine to load compensate my manshed supply and use a MorningStar to actually charge them.

I think you'll find the absorption times too short (by several days at times) regardless. Victron EQ is another redundant feature that doesn't work. Too conservative for golf carts ie. AGM bias again. To compound this it's pulsed not consistent.

If you have a 30v constant voltage supply you can be the manual regulator...turn it off after a few days when you hit your SG target.

Digital hydrometers don't last long in acid bath.

If you want to stick a band aid on the situation you can raise the absorption to 2.62V p/c until April.
For now keep resetting EQ until SG stops improving. 6 hours at 32v and probably then some.


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Scruff on January 24, 2019, 11:25:54 AM
I don't think you're worrying unnecessarily. If you charge to 1.275 SG yer crowns will be immortal.

Charging to only 1.265 SG is degenerative cycling and makes a ground breaking case for smanchy expensive li-smions.

To be honest I bet 30 cell panels with an MS PWM controller will knock the socks off a Victron MPpT.

(http://www.boards.ie/vbulletin/attachment.php?attachmentid=469478&stc=1&d=1546568228)


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Pord on January 25, 2019, 03:48:13 PM
Thanks Scruff, very much appreciated.

The current absorption value is set at 29.6v, so when you say raise it to 2.62v per cell, is that simply 12 (cells) x 2.62 = 31.44?

EQ currently set at 31v, so I'll give that a nudge up to 32v.


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Scruff on January 27, 2019, 10:43:10 PM
Yes but set absorption to EQ threshold until it's fully charged.
As I say Victron EQ doesn't work.


Title: Re: Battery monitor says 100% charged, SG says not
Post by: eabadger on January 29, 2019, 06:48:57 AM
even the multiplus inverters have an odd way of eq.

i treated us to a victron bmv712 and a vrm box.
having fiddled with the peukert's settings and our bmv now matches sg pretty well.
we have a high load and charge regime on lead acid forklift cells.
i find the vrm app good for when i am away, it can send the wife emails to remind her to run the generator or errors.

steve


Title: Re: Battery monitor says 100% charged, SG says not
Post by: camillitech on January 29, 2019, 08:10:23 AM
As soon as I saw this thread I thought, Pord needs to bin the Victron and buy a Morningstar but had no data to back up my statement. You put it so eloquently Scruff  :genuflect

The second is Victron are AGM biased for mostly idle systems like posh boats and lawsuit mitigation. They spend more on marketing than product R&D.
I've given up trying to charge batteries with them. I just use mine to load compensate my manshed supply and use a MorningStar to actually charge them.


 :hysteria  :hysteria

P


Title: Re: Battery monitor says 100% charged, SG says not
Post by: eabadger on January 29, 2019, 08:31:50 AM
i should have also said that.

4 x morningstar controllers here.
vrm and bmv seem good.
but as i said even the multiplus inverters are odd for setting to eq.

steve


Title: Re: Battery monitor says 100% charged, SG says not
Post by: camillitech on January 29, 2019, 08:46:52 AM
i should have also said that.

4 x morningstar controllers here.
vrm and bmv seem good.
but as i said even the multiplus inverters are odd for setting to eq.

steve

Four here too Steve and I wonder if Victron use the same algorithm as SMA cos I've given up on mine  ;D

P


Title: Re: Battery monitor says 100% charged, SG says not
Post by: eabadger on January 29, 2019, 09:04:07 AM
i like to remote monitor as battery shed 100m away, so have 3x mppt morningstars and now the bmv was hoping to export the solar data to the victron unit but when i tried had an issue, which victron are still working on.
our multiplus's are in master slave, but the slave has an issue, victron dealer here wanted 1200 to fix under warranty !!
so went back to victron, who had it a week and said nothing wrong, came back still faulty, going back again now they have agreed with my diagnoses and seen a video to prove issue!!
only need the two in the summer anyway to start the heat pump.
but give ability to charge higher when genset running.

steve


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Scruff on January 29, 2019, 09:43:13 AM
I have 8 MS Controllers the ninth is about to get sold. For battery monitors I've a BMV,  Bep marine, ApprenticeVolt, Trimetric, Studer and two Smartgauges(48v)
The Smartgauge is ok.
Trimetric is the only one I'd recommend for  true off gridding.


Title: Re: Battery monitor says 100% charged, SG says not
Post by: eabadger on January 29, 2019, 10:03:41 AM
wow!!
"I have 8 MS Controllers"

why so many?
i get nervous when our 3 are outputting near on 180a.
the 4 one is on the spare bank.

not much sun today, but yesterday and sunday were good.

steve


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Scruff on January 29, 2019, 03:35:08 PM
They looked lonely. whistle

EcoPulse PWM & Sunsaver MPPT in service, 2 x  Spare TriStar 45 PWM, 1 x Spare TriStar 37.5MPPT, Gen 2 ProStar...looking for home, Spare SunSaver MPPT, Spare Remote Meter, Spare TriStar Meter, SunSaver...hanging out, beside my spare inverters in my spare 20' container.....anyone wanna hire a 20kVA solid state genset? 

No ProStar Gen 3's yet   :'(

You what's a great feature in a battery monitor? Legibility!




Title: Re: Battery monitor says 100% charged, SG says not
Post by: Pord on January 29, 2019, 04:54:57 PM
Scruff, as a beginner can I check that I properly understand your advice - set both absorption and EQ to 32V. When SG indicates fully charged (approx 1.29 at current 5degC), revert to original settings 29.6v and 31v respectively. Have I got that right?

Yes, I may come back for advice on replacing the Victron 100/50 mppt controller with a suitable Morningstar (second hand, if there's any available for sale...?)



Title: Re: Battery monitor says 100% charged, SG says not
Post by: Scruff on January 29, 2019, 07:27:47 PM
Set absorp to 32V until charged.

I don't advise reverting back to a setup that isn't working.


Don't feel bad, you're not the first person a manufacturer has led up the garden path, par for the course. We all end up buying into the marketing, figuring out its a loada shyte and then getting something proper instead. If it's not the case then you're either incredibly lucky or haven't noticed yet.

If the battery is 1.275SG (at correct water level) once a month then problem solved.



I only have A gen2 ProStar 30M PWM on the to go list...pm me if you want that one (cheep enough), I also have the world's only Sunsaver 1210 with a remote temperature transistor sensor I could be persuaded to part with. I ship all my preloved controllers with a free DIY temp. sensor kit.


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Pord on January 30, 2019, 05:35:08 PM
Thanks Scruff (and for the PM too).

I changed the absorption to 32v and after some good sunshine today the SG is at 1.27-1.28 (actual, temp is 5degC). It's definitely helping, so I'll continue with the current setup for now, especially as we have more sunshine forecast. The controller never reached absorption.

I did notice today that during sustained sunshine, when the controller app would reach over 300w at around 5a and 70v, it would stop charging. It cycled through that process continually during bright periods. Is that normal, based on my settings? Or is that Victron...? (See, I'm learning!)



Title: Re: Battery monitor says 100% charged, SG says not
Post by: eabadger on January 30, 2019, 06:25:06 PM
not sure about the victron, but my mppt morningstars say 150v max input and ramp power output down from 135v upwards, shows a diagram of this in manual maybe victron do similar.
i have seen peak sun outputs put my controllers in to alarm, normally after slight cloud cleared.

steve


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Scruff on January 30, 2019, 10:10:48 PM
I wonder if Victron use the same algorithm as SMA cos I've given up on mine  ;D

Same goes for most competitors. 1.27 was the best I've seen off the shelf from Sterling/ProNautic.
Some people don't know how to use their electrolyte as coolant.  ::)

Hence I convert MS Mppt jobbers into Mains chargers.

I changed the absorption to 32v and after some good sunshine today the SG is at 1.27-1.28 (actual, temp is 5degC).

That was quick. Carry on. Don't overdo it. If you do overdo it, it's better than underdoing it.


I did notice today that during sustained sunshine, when the controller app would reach over 300w at around 5a and 70v, it would stop charging. It cycled through that process continually during bright periods. Is that normal, based on my settings? Or is that Victron...?

Both.
That controller has a feeble heatsink for it's rating.
From the people who proclaim expected operating temp. derating as a reliability feature!
" Protection against overheating: the output current will reduce as
    temperature increases up to 60C, but the charger will not fail."

MorningStar can maintain 100% Duty, 100% of the time. (http://www.navitron.org.uk/forum/Smileys/classic/onpatrol.gif)


i have seen peak sun outputs put my controllers in to alarm, normally after slight cloud cleared.

Cloud Edging Overvoltage.
Is your max. temperature compensated Panel Voc uprating below the MS PV in Voc thresholds?


Title: Re: Battery monitor says 100% charged, SG says not
Post by: eabadger on January 31, 2019, 06:57:58 AM
"MorningStar can maintain 100% Duty, 100% of the time."

my morningstar's derate in heat, and high input current, manual shows graph of it.

steve


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Scruff on January 31, 2019, 09:53:01 AM
...on rare occasions, when the heatsink reaches 80C

not like my Victron IP charger that reduces to 85% output 3 seconds after starting. 60C feeble internal heatsink.



Title: Re: Battery monitor says 100% charged, SG says not
Post by: eabadger on January 31, 2019, 02:54:39 PM
did it loads here last summer, i had to hook a fan up in shed to keep them cool.
they also start derating i think when input goes over 130v, according to their support team, mine all kept reporting dipswitch change error when sun came out from cloud cover, apparently known fault being fixed...
had another one stop working last summer, they changed no problems, fault was diagnosed by unit as dipswitches incorrect, not sure if conected with known software bug, but that controllers dipswitches has a dark hole in it, the network both serial and tcp stopped working, not had time to check it out yet, but hope to soon.

steve


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Scruff on January 31, 2019, 08:22:03 PM
I run my sunsaver 15 mppt at full tilt often enough. I've not seen my others derate. Ireland.  :winter


Title: Re: Battery monitor says 100% charged, SG says not
Post by: eabadger on February 01, 2019, 08:13:08 AM
with the 3 on the left hitting 60a each they got very warm in last summers heat, batterys were charged by midday so wasting power, but then got the ASHP, so after batts had been absorbing for x the ashp comes on, so they were 60a from about 10am till about 8pm, so cant complain.
hooked a fan from the ceiling, very heath robbison, but did the job, had plans to make a better effort over winter for next summer, but..............

steve


Title: Re: Battery monitor says 100% charged, SG says not
Post by: Scruff on February 03, 2019, 05:20:36 PM
(https://i.ebayimg.com/images/g/fdMAAOSwNexb4Yuz/s-l500.jpg)

Clicky (https://www.ebay.co.uk/itm/ZHIYU-DC-12V-24V-48V-2-Way-Cooling-PWM-4-Wire-Fan-Temperature-Controller-Tempera/173626267258?hash=item286cee967a:g:QJQAAOSwC8pb4Yuz:rk:5:pf:0)