Apologies, crossed messages, thank you @roadtripper
Lithium LifePo4 12v Batteries - Time For An Upgrade?
- Thread starter Dellmassive
- Start date
Hysteresis, my new word for the month! Thanks again RT
Well I learnt a new word from @roadtripper - hysteresis. Just need to work out how to shoehorn that into a conversation now!
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Think of it this way. If you've ever used a digital thermometer you'll have seen two sources of error.
The reading moves around a lot as the sensor is sampled. That's once source of error the stability of the measurement.
When you compare several they tend to not quite agree on the temperature, that is another source of error the accuracy of the measurement.
In this case we know we want to block charging when the temperature is definitely below zero, so if we set the change over as +2.5 degrees we'd account for the accuracy error (assuming that the error is it will be within 2.5 degrees of the right temperature)
Now we could release the block as soon as the temperature crossed back over +2.5, but the other error will creep in here, we absolutely don't want 30A charging being turned off and on several times a minute as the sampled temperature moves from 2.51 to 2.49 and back again.
So we say that once the charge is blocked we must not release until we are definitely over +2.5 and with an accuracy error of 2.5 that's +5
Similar hysteresis techniques will be going on throughout the ECUs in the van to bring stability of operation.
The reading moves around a lot as the sensor is sampled. That's once source of error the stability of the measurement.
When you compare several they tend to not quite agree on the temperature, that is another source of error the accuracy of the measurement.
In this case we know we want to block charging when the temperature is definitely below zero, so if we set the change over as +2.5 degrees we'd account for the accuracy error (assuming that the error is it will be within 2.5 degrees of the right temperature)
Now we could release the block as soon as the temperature crossed back over +2.5, but the other error will creep in here, we absolutely don't want 30A charging being turned off and on several times a minute as the sampled temperature moves from 2.51 to 2.49 and back again.
So we say that once the charge is blocked we must not release until we are definitely over +2.5 and with an accuracy error of 2.5 that's +5
Similar hysteresis techniques will be going on throughout the ECUs in the van to bring stability of operation.
I'm just glad it works!
I get the theory, just never heard of the word. Every day's a school day on here.
Can you go into both apps and screen shot them separately... Im Wondering if you have a FW that shows the temp on your Orion now?.. (the demo file didn't show a temp option for the orion)
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Then go to the end tab in the app and see if temperature is highlighted or greyed out... And graph it
Mines highlighted as I have a separate temp sensor.
You can see mines showing 12c.
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Afaik - That temp option has no effect unless you have the external temp sensor, so effectively it does nothing and won't stop any charge below 5c.
I'd imagine your BMS has different values than 0c and 5c...
You can contact Steve and gang @RoamerBatteries to check the BMS configuration in regards to the low temp cut out and restore.
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You should be able to charge down to 0c, if you go below 0c then the BMS will block incoming charge..... Until the battery gets back to +5c... The all resets bank to normal.
I know I don't have an external temp sensor. It just surprised me that when the battery had been minus temps for days, as soon as it hit 1 degree the solar started performing again. At no point did it hit 5deg to reset it. As soon as Sarah stops talking about her night shifts I'll get out in the van to screenshot some stuff!
BMS can be set between 1 and 5 in whole numbers.
Battery temperature is greyed out...
That's it! I'm going to torch it!
Lovely sat in the back though with the diesel heater on, warmer than the house!
Twinkly lights on burning some free power, happy as Larry...
So as we thought no temp control on the Victron MPPT without the external temp sensor. The Orion doesn't have temp sensor either.
And your Roamer will allow charge down to 0c.
If it goes -1c then should block charge until +5c.... If not the BMS parameters can be checked.
And your Roamer will allow charge down to 0c.
If it goes -1c then should block charge until +5c.... If not the BMS parameters can be checked.
Thank you Mr Massive, yesterday was the first day for over a week it went above 5 degrees. I'm off today, I'll have a play with my BMS's!
you can use one of these. . . that will send Temp data over BT to the MPPT. . .
but unfortunatly the 12/12/30 Orion has no Smarts. . . and will not detect any temp data.
but the new 12/12/50 Orion XS will - soon via FW updated.
Smart Battery Sense - Victron Energy
Improve the charging-efficiency and prolong the life of your batteries with the Smart Battery Sense. Find a dealer near you.
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or add a BMB712 with temp sensor.
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That'll be a confirmed purchase when it's available. Any idea when and £'s?you can use one of these. . . that will send Temp data over BT to the MPPT. . .
but unfortunatly the 12/12/30 Orion has no Smarts. . . and will not detect any temp data.
but the new 12/12/50 Orion XS will - soon via FW updated.
Smart Battery Sense - Victron Energy
Improve the charging-efficiency and prolong the life of your batteries with the Smart Battery Sense. Find a dealer near you.www.victronenergy.com
View attachment 226633
View attachment 226634
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or add a BMB712 with temp sensor.
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Pollogies, Dr Google has answered, less than £400 and availability is February.
So, can I slip you £200 for yours? You don't need another surely?!!!
So, can I slip you £200 for yours? You don't need another surely?!!!
I’m trying desperately to learn all about this.
But TBH my head still hurts from last night’s information explosion.
I’m just going to keep reading but it’s hard going
But TBH my head still hurts from last night’s information explosion.
I’m just going to keep reading but it’s hard going
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