Have a read down in section 8.3 of the installer manual.. ->
Not sure if it'll help, but it's something to try =)
anyone here know anything about this inverter need to set the VdcBatMax to 25.2V but it is locked behind hidden menu.
also can connect to it by Sunny Data Control using rs485 but that is locked by password.
Look Here -> |
Have a read down in section 8.3 of the installer manual.. ->
Not sure if it'll help, but it's something to try =)
there is 3 levels of security "user" "inst" and "sma" the VdcBatMax is hidden under the level 3 menu.
the lithium battery i have is 25.2V max it is trying to charge it to 27V.
After a slower read of the same install manual, I can't find VdcBatMax.... I can see VdcBatNominal ..... right above BatType, which gives you 2 options, neither of which is for lithium based cells (or custom type).
VdcBatNominal you should be able to access though, which in theory should affect batmax value ....what battery is it btw?
its a Tesla battery goes all night and gets down to 24V by the morning.
Charge voltage cut-off(Battery module) 25.2V/Module
Nominal voltage (Battery module) 22.8V/Module
Discharging cut-off(Battery module) 19.8/Module
if you set the VdcBatNominal to 22.8V it shuts off at 21.8v and saves in the error log battery critical low.
if you change ANY setting 3 times it permanently locks you out then needing the level 3 password to make any changes.
yes i have contacted SMA and the response is basically die in a lithium fire we are not giving you the password for your safety.
yes i have read the firmware and can see all the extra menus.
Hahaha....the danger of lithium battery storage fire is well known, and because they tend to produce their own oxygen as part of the chemical fire, they self-feed and a near impossible to extinguish.
What's laughable, is SMA thinking their system could be responsible for same, but what is true is their system probably isn't capable of monitoring and/or detecting an abnormal condition, in a particular lithium cell (of the battery itself).
Charge voltage cut-off(Battery module) 25.2V/Module
Nominal voltage (Battery module) 22.8V/Module
Discharging cut-off(Battery module) 19.8/Module
Most all 2 terminal (+/-) lithium based battery packs that get charged via the same terminals in the way you treat a lead-acid car battery...be they 12/24/48volt batteries... are actually a whole bunch of lithium cells connected in parallel/series to arrive at the required terminal voltage/battery capacity. Built into these batteries (usually under the top cover) is a BMS controller, and it's this circuit that controls the charging of the individual cells in a balanced way (and a good BMS will report if any cells start to act abnormally), and it'll no doubt be this very system defining the discharge/charge cut-off points.
So, in reality, you're not trying to charge a chemical storage cell using a defined charge profile as per normal, you're merely providing power for the builtin BMS to do the actual charging in a controlled way....usually speaking....ie; if the charger's providing 27volts, the BMS is going to stop charging once the terminal voltage reaches 25.2V regardless.
The only scenario that would be a bother, is if the BMS refused to charge because it considered 27volts too high....but I kinda doubt it.
That's why I wanted to know about the battery...brand/model...just to see how it's constructed and full specs are =)
VroomVroom (06-12-22)
looks like eeprom attack time just can't work out the stupid crc's.
M'kay....with no info, best I can gather is this is a 6 gang 24v tesla battery, no BMS...so now I see where SMA are coming from ; the charge controller can't do a lipo profile.
Max charge voltage for these batteries is somewhere around 24.5vdc for longevity ; float voltage a poofteenth lower at around 24.3vdc. You can set VdcBatMax to whatever you want, as once the controller goes into charge mode it's gunna...
Got that?.... 27 volts DC is the MINIMUM battery charging voltage ~ this is what you were originally complaining about.
That figure is arrived at because this charge controller/charge profile is designed for lead-acid (flooded/gel) type batteries, and a minimum charge voltage of 27volts is entirely sane with a 24volt lead acid battery.
If I thought it out right, the only way the SMA controller would do the required charge voltage for lipo, was when it was in 'float' mode, as any bulk mode = 27volts.
This is why I and all I know use victron charge controllers ; you can customize your battery charge profiles to suit ~BUT~ (many of) their controllers are built to handle all battery types from the get go ; this SMA controller might not be able to bulk charge @ 24.5vdc (and by the sounds of it SMA aren't going to tell you) ; might actually require revision at component level....best case scenario is you wreck your tesla battery, worst case is you start one of those unstoppable fires with it =)
there IS new firmware update for this inverter that changes the charging parameters from 27V~31.9 to 21V~35V without modding the hardware.
getting it is another story.
locating the float boost full charge default values in firmware should not be that hard the new type of crc is a pain.
can't skin a cat one way try it another way.
"The Sunny Island was originally designed to use Lead Acid batteries, only. Lithium-ion support was added as a firmware update and does not contain any BMS logic. It requires an external BMS to provide details of the battery SoC, SoH, charge current need, etc. If it does not receive valid BMS data within a period of time, it will shutdown."
I got there via .... (have a read through that to discover just how many parameters need changing)
Apparently the REC BMS equipment talks SMA (might be later firmware at a guess) ....
Take the hint -please- ; if the later firmware you speak of is designed to work with external BMS, that infers the SI3324 can't do the job for lithium based storage.
Last edited by wotnot; 05-12-22 at 05:43 PM.
you are being a drama queen and i am starting to think you know nothing about lithium ion battery's.
i have had 18650 battery's since 2001 getting the data sheet was hard.
i build electric scooters and bikes.
i like ANT and IC GOGOGO BMS boards they have Bluetooth so i can see the cell voltages on my phone and the battery temperature.
lithium ion battery's are SAFE just don't break these rules and you will be fine.
DO NOT OVER CHARGE THEM THEY WILL HEAT UP AND CATCH FIRE.
how do i avoid this.
easy set bms to 25.5v MAX it will stop charging the battery so no fire.
monitor temperature stop charging/discharging if it gets over 45c BMS does this and so does the sunny island.
do not over discharge cells it damages them and may catch fire during charge BMS will stop discharge at 19.5v.
lithium ion battery's are just like cars don't drive drunk and stoned at 200kmph and you will be fine.
my experiments with old cells and a thermal camera i saw some interesting shit.
overcharging cells they all seem to make it to 60c then get super angry and go to 1000c.
stop over charging them at 50c and no fire keep charging them to 60c then stop and still get fire.
i would like to set the sunny island to 25.2V BUT some control freak has decided to make things hard so i am stuck at 27V for now i have figured out the crc's and the block sizes so now can change anything i like.
WE HAVE A WINNER.
eeprommemory = 1
SMA control freaks = 0
NEW firmware default settings.
VchargeBoost 25.200 Vdc 25V ~ 31.2V
VchargeEqual 25.100 Vdc 25V ~ 31.2V
VchargeFloat 25.000 Vdc 25V ~ 31.2V
VchargeFull 25.100 Vdc 25V ~ 31.2V
VdcBatNormal 20.8 Vdc
also can keypad set voltages from 25V ~ 31.2V.
charger has not stepped a millivolt over 25.1 so NOT triggering BMS.
time wasted hacking it 4 HOURS.
time wasted searching internet / emails to sma / here / other. 2 WEEKS.
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