Victron 75/15 thinks it is -18deg C. Not charging.

[Kannon Fodda]

Bit weird. I have no temp sensor. Firmware is current. But the mppt is deciding battery is well below freezing. I'm standing here in shorts and factor 50. More likely its +18 with battery in shade, and probably much warmer in sun.

As controller on the standard lithium profile thinks it's unsafe to charge, nothing is doing. As I have no temp sensor on battery, mppt or smartshunt, why is it seeing the temp, and seeing it wrongly?

I can set my own battery profile to disable the temp monitoring, as a workaround.

 

[Googlebot]

Is it because the smart networking is enabled?

I have a feeling if is and it can’t see a temp sensor, it may just register -18 to protect the batteries.

 

[Kannon Fodda]

Yes smart networking is on, but had been for the last year plus without issue. I've only seen this non charging due to temp problems in last month. Once I start fiddling it seems to cause a reset on the temp after10 mins or do, until the next time.

 

[Googlebot]

Yes smart networking is on, but had been for the last year plus without issue. I've only seen this non charging due to temp problems in last month. Once I start fiddling it seems to cause a reset on the temp after10 mins or do, until the next time.

Probably a software issue with the new update then. :-(

Or you could get a temp sensor?

 

[RedFrame]

I know it may be a stupid question, but have you removed the jumper switch?

Cheers
Red.

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[Guigsy]

It's probably a bug in the update. It might even go away if you play with the settings and then put them back again. It's pretty common in software for updates to screw up when porting settings from previous versions. Especially if you've skipped a couple of updates.

 

[Kannon Fodda]

I know it may be a stupid question, but have you removed the jumper switch?

Cheers
Red.

It is now. Although I've done a lot with my hab electrics, the Victron was first fitted by others so wasn't something I'd checked.

I've now done a bit more digging and a bit of RTFM Apparently the MPPT has an internal temperature sensor. Manual says it's used to set temperature compensation voltages, and also to determine if the MPPT is overheated. So it shouldn't be affecting this issue.

The low temperature cut off thing is, according to the same manual, only active if the charger is part of a VE Smart Network [it is] and is receiving a battery temperature reading from a battery sense / monitor [it shouldn't be]. But the standard lithium profile in the MPPT app is activating this low temp cut off, apparently at 5 deg C. Something is screwy. I'll set my own battery profile for now to disable that setting, but still doesn't explain the -18 deg C reported.

 

[Guigsy]

It is now. Although I've done a lot with my hab electrics, the Victron was first fitted by others so wasn't something I'd checked.

I've now done a bit more digging and a bit of RTFM Apparently the MPPT has an internal temperature sensor. Manual says it's used to set temperature compensation voltages, and also to determine if the MPPT is overheated. So it shouldn't be affecting this issue.

The low temperature cut off thing is, according to the same manual, only active if the charger is part of a VE Smart Network [it is] and is receiving a battery temperature reading from a battery sense / monitor [it shouldn't be]. But the standard lithium profile in the MPPT app is activating this low temp cut off, apparently at 5 deg C. Something is screwy. I'll set my own battery profile for now to disable that setting, but still doesn't explain the -18 deg C reported.

Have you got a shunt in the network? Is it detecting temperature or voltage? Regardless, try switching the setting, saving, then switching it back.

 

[Kannon Fodda]

I have the Victron 75/15 MPPT and Smartshunt linked by bluetooth. Shunt is doing voltage and sending that to the MPPT. No temp sensor attached. Will try messing with those settings tomorrow.

 

[ChrisL]

On the shunt, have a look at settings/misc/aux and see if you have temperature set on, this should only be on if you have a temperature sensor fitted.

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[headlight]

I don't have temp sensor.
If I tap on the cog icon on the top right corner of the shunt page then tap on misc I see, Aux - None, which I think is what you should see

 

[Kannon Fodda]

I don't have temp sensor.
If I tap on the cog icon on the top right corner of the shunt page then tap on misc I see, Aux - None, which I think is what you should see
View attachment 763743

Yep that's what mine was showing.

 

[gerry mcg]

If you have lithium, get a Smartbatterysense for £35.
Though not necessary just now, essential in winter.
If you don't have a SBS, Turn off ve.networking

 

[peterc10]

If you have lithium, get a Smartbatterysense for £35.
Though not necessary just now, essential in winter.
If you don't have a SBS, Turn off ve.networking

I agree. It is essential to ensure that the battery is not charged if it is below zero degrees. I would not rely only on the BMS alone to do that. They do occasionally go wrong. I fitted additional temperature sensors for my Votronic solar regulator and B2B and also a Bluetooth one for both the Victron solar regulator and mains charger. Cheap enough for belt and braces compared with the cost of replacing the battery.

 

[monzer]

If you have lithium, get a Smartbatterysense for £35.
Though not necessary just now, essential in winter.
If you don't have a SBS, Turn off ve.networking

I agree. It is essential to ensure that the battery is not charged if it is below zero degrees. I would not rely only on the BMS alone to do that. They do occasionally go wrong. I fitted additional temperature sensors for my Votronic solar regulator and B2B and also a Bluetooth one for both the Victron solar regulator and mains charger. Cheap enough for belt and braces compared with the cost of replacing the battery.

I've 2 lithium batteries, each with a Victron Battery Sense. Victron shunt and MPPT all connected on the network yet my MPPT suddenly thinks the batteries are -1 degree c. Disconnect from the network and all is fine again.

Both BS's are reading correct temperature. Just an issue with the MPPT. It's been working fine for best part of a year so not sure what has changed.

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[autorouter]

I don't have temp sensor.

All the Victron MPPTs, including the 75/15, have an internal temperature sensor, which it uses if there is no external sensor configured. Possibly something might have gone wrong with that sensor. Usually on a circuit board it will just be a diode fed by a known small current, and a way to measure the diode voltage as it varies with temperature.