Victron BMV 712 settings?

[Next Stop]

Does this look right?

should it not be reading around 70%?


Single 130amp AGM battery

 

[Guigsy]

Is the BMV brand new? You have to charge it up to full before it knows where 100% really is.

 

[Two on Tour]

Have you synchronised the BMV to 100% SOC when your battery is at full charge i.e. in it's absorption phase ?

 

[Next Stop]

I did when it was first set up haven't really used it as it been sitting I the drive, although I did unplug it to reroute the cable, will it need resetting perhaps?

 

[Two on Tour]

Victron do say that you need to fully charge your batteries at lease twice a month for the SOC to synchronise.

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[Next Stop]

Victron do say that you need to fully charge your batteries at lease twice a month for the SOC to synchronise.

Thanks for this link, just watched it and kept thinking what's a "parra-meter",
I've only charged the battery once in the six weeks I've had it as the van is still being built, just finished installed the shore power so I can now easily charge again, a question on the charged voltage though, is this specification found on the battery jargon sheet or is it just obtained from the BMV once the battery is fully charged?

 

[Two on Tour]

a question on the charged voltage though, is this specification found on the battery jargon sheet or is it just obtained from the BMV once the battery is fully charged?

Best to use info from the battery manufacture for their battery.
As an example the Hankook XV110 battery was way different bulk, absorption and float voltages to batteries of a similar type and as such was not being fully charged.

 

[Lenny HB]

It takes a fair bit of work to get the state of charge to read correctly, it took me over a week of tweaking the the settings to get it accurate.

You need to set the battery capacity to allow for age, deduct 2.5% for each year of battery age (and remember to do it every year).
Charger efficency setting probably 75-85% (default is 95% I think).
Tail current & discharge floor need setting for the type of battery.
Peukert exponent is probably OK at at 1.25.

Also when syncing you need to do it after the absorption phase but if the charger goes into float mode you need to leave it on float 24 hr before syncing.

 

[Next Stop]

Best to use info from the battery manufacture for their battery.
As an example the Hankook XV110 battery was way different bulk, absorption and float voltages to batteries of a similar type and as such was not being fully charged.

Hmmm, just looked at the spec sheet and I cannot see a definitive figure?

 

[Lenny HB]

I set mine for manual sync you do this by setting the charged voltage higher than max charge voltage.
My charger takes my Gels up to 14.4v so I set the charged voltage to 14.6v.

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[Raul]

I did when it was first set up haven't really used it as it been sitting I the drive, although I did unplug it to reroute the cable, will it need resetting perhaps?

Yes, when you disconnect the power supply, it re sets to 100% SOC automatically, regardless of battery state of charge. What are your settings, I can help you dial in more appropriate values, to prevent premature re synchronisation. I run two of these fairly accurate, within 1%.

 

[Next Stop]

Yes, when you disconnect the power supply, it re sets to 100% SOC automatically, regardless of battery state of charge. What are your settings, I can help you dial in more appropriate values, to prevent premature re synchronisation. I run two of these fairly accurate, within 1%.

Hi Raul,
My setting are as below...

The system has just one 130ah AGM battery.

 

[Raul]

It takes a fair bit of work to get the state of charge to read correctly, it took me over a week of tweaking the the settings to get it accurate.

You need to set the battery capacity to allow for age, deduct 2.5% for each year of battery age (and remember to do it every year).
Charger efficency setting probably 75-85% (default is 95% I think).
Tail current & discharge floor need setting for the type of battery.
Peukert exponent is probably OK at at 1.25.

Also when syncing you need to do it after the absorption phase but if the charger goes into float mode you need to leave it on float 24 hr before syncing.

You don’t need to sync it, dial in the values, and it will do it automatically when all are met. You can do it manually by pressing the two buttons, but, you need to be 100% sure you have charged it to full. That sync is just a reference point, until next sync will take place. Due to peukert, temperature, charge and discharge rate etc, it will drift. Hence the values need to be met to re sync to a new reference point. This happens if you give it a true full charge.

 

[Raul]

Reduce battery capacity to 125ah for now.
Charged voltage ( absorb assumed voltage in your charger) 14,4v
Discharge floor 50% is good
Tail current 1%
Charged detection time 30 mins.
Peukert exponent 1,4
Charge efficiency factor 80%

Try this settings and wach amps amorphous disappear to 0 before it syncs to 100% soc.

 

[Next Stop]

Reduce battery capacity to 125ah for now.
Charged voltage ( absorb assumed voltage in your charger) 14,4v
Discharge floor 50% is good
Tail current 1%
Charged detection time 30 mins.
Peukert exponent 1,4
Charge efficiency factor 80%

Try this settings and wach amps amorphous disappear to 0 before it syncs to 100% soc.

Thanks for this, I'll give it a try in the morning, give the battery a full charge and report back!

Cheers
Martin

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[gerry mcg]

Reduce battery capacity to 125ah for now.
Charged voltage ( absorb assumed voltage in your charger) 14,4v
Discharge floor 50% is good
Tail current 1%
Charged detection time 30 mins.
Peukert exponent 1,4
Charge efficiency factor 80%

Try this settings and wach amps amorphous disappear to 0 before it syncs to 100% soc.

Thanks for a really useful thread and replies.
It looks like I need to fiddle with the stock settings on my BMV700

 

[Next Stop]

New setting applied and battery charged, my Victron charger was in absorption mode at this point, all I need to do now is try and suck some juice from the battery!

 

[Raul]

It will matter in the next cycle. If you set new values before charging then it would calculate different. As it was, it carried on with what it had, until you changed. After you changed, it was already in absorb, not much time left to go by. At least, it prevented a premature sync. How many - amps was left before it went to float?

 

[Next Stop]

It will matter in the next cycle. If you set new values before charging then it would calculate different. As it was, it carried on with what it had, until you changed. After you changed, it was already in absorb, not much time left to go by. At least, it prevented a premature sync. How many - amps was left before it went to float?

Hi Raul,
I changed the settings before I started charging, I think when I glanced at the charger it started in bulk mode, came to the van this morning and unplugged from the shore power and the readout settled to 13.27v after switching off the charger, not sure how many amps were left before it went into float, can I find this out from the chargers history? (Victron Blue Smart)

<M>

 

[Raul]

It won’t be in the history. It’s only if you are around and notice amps left to put in before it drops in absorb. The only thing is logged, is the deepest and average discharge. First time I noticed this I realised the victron settings are generic and needs playing up to suit individual system. I noticed -15-16ah to go and it was charging under 10amp at the time. Five minutes later it reset to -0ah and 100% of charge. The battery still charged until sundown hrs later. The settings victron gives are not near enough time to consider full charge. Maybe this suits their batteries, I don’t know.
For now, monitor % soc and give it few days. The microprocessor still adjusts and learns the system. If after 4-5 days nowhere near then further adjustment will bring it closer. I always rely on amps to go rather than % soc. The amps to go are accurate true coulomb count. Where the percentage is a approximation.

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[Next Stop]

It won’t be in the history. It’s only if you are around and notice amps left to put in before it drops in absorb. The only thing is logged, is the deepest and average discharge. First time I noticed this I realised the victron settings are generic and needs playing up to suit individual system. I noticed -15-16ah to go and it was charging under 10amp at the time. Five minutes later it reset to -0ah and 100% of charge. The battery still charged until sundown hrs later. The settings victron gives are not near enough time to consider full charge. Maybe this suits their batteries, I don’t know.
For now, monitor % soc and give it few days. The microprocessor still adjusts and learns the system. If after 4-5 days nowhere near then further adjustment will bring it closer. I always rely on amps to go rather than % soc. The amps to go are accurate true coulomb count. Where the percentage is a approximation.

Thanks for you help and sharing your knowledge, I'll monitor and report back, I just need to wire up the fridge as it's going to take weeks to discharge off the LED lights! That's this weekends fun sorted!

<M>

 

[gerry mcg]

On the suggested updated bmv settings I'm struggling to get the battery's to reach 100% SOC now on Solar top up.
I've got the compressor fridge only running, and that seems to draw 13A or so overnight, but the SOC is only getting back to 96 % -6A) by sunset. I accept the fridge will draw another 13A or so in the day during charging.

I find that hard to believe with 175W Solar during mid summer Bright / sunny days (albeit at 55N in Glasgow)

Any ideas

 

[Raul]

On the suggested updated bmv settings I'm struggling to get the battery's to reach 100% SOC now on Solar top up.
I've got the compressor fridge only running, and that seems to draw 13A or so overnight, but the SOC is only getting back to 96 % -6A) by sunset. I accept the fridge will draw another 13A or so in the day during charging.

I find that hard to believe with 175W Solar during mid summer Bright / sunny days (albeit at 55N in Glasgow)

Any ideas

What batteries do you have?

 

[gerry mcg]

2x95Ah Varta AGM, 4 yrs old but not abused and not heavily used

 

[Raul]

The suggested settings was for that specific case your will be diferent. Agm have high charge efficiency. What’s the absorb and float settings in your solar charge?

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[gerry mcg]

The suggested settings was for that specific case your will be diferent. Agm have high charge efficiency. What’s the absorb and float settings in your solar charge?

I've got a victron 75/15 MPPT solar controller set to the default Spiral AGM charge profile as attached

 

[Raul]

Based on the info provided I would try this settings. Not you do not want the bmv to reset to 100% prematurely, and if bmv says 96% I would trust its count.

Battery capacity 180ah
Charged voltage 14,4v
Charged detection time 15mins
Tail current 1%
Discharge floor 50%
Peukert exponent 1,35
Charge efficiency factor 90%
The agm,s are incredibly efficient on charging from 50 to 80-90% state of charge in bulk, the last 20-10% in absorb, not so. The same goes with shallow cycle, if you only cycle the top 20%, expect to pay in the inefficiency of absorb. For every 10ah used, expect to put back as much as 15ah to full.

 

[gerry mcg]

Thanks. I've tweaked the settings & will keep an eye on it. It was definitely resetting to 100%SOC too early with the bmv 700 factory default settings. It would often show 100%SOC by 9am before

 

[gerry mcg]

Based on the info provided I would try this settings. Not you do not want the bmv to reset to 100% prematurely, and if bmv says 96% I would trust its count.

Battery capacity 180ah
Charged voltage 14,4v
Charged detection time 15mins
Tail current 1%
Discharge floor 50%
Peukert exponent 1,35
Charge efficiency factor 90%
The agm,s are incredibly efficient on charging from 50 to 80-90% state of charge in bulk, the last 20-10% in absorb, not so. The same goes with shallow cycle, if you only cycle the top 20%, expect to pay in the inefficiency of absorb. For every 10ah used, expect to put back as much as 15ah to full.

Raul , hmmm... I'm not sure these BMV settings are working for me.
The SOC IS not getting too 100% now, even after being plugged into hookupp.
The consumed amps has remained at -9A, dispite bring on mains hookup for 24h.
Any ideas on what to tweak?

 

[Raul]

Increase tail current to 2% and decrease charged detection time to 10mins. You have a weak charging source for your capacity.