Lithium Newbie

[Mark_K5LXP]

Originally Posted by xc-mark

Its not good for lead acid battery of any type to be discharged below 50% SOC.

There is nothing significant about 50% DOD that impacts service life. Based on that premise it's not good to discharge any battery to any depth of discharge. Even not using them at all they'll go bad eventually. So what's the point of having a battery unless you use it? 80% DOD (100%Ah) is within the rated spec for deep cycle lead acid batteries. 50% can be a logistical or operational threshold for a given application and that's fine, but there's no "damage" or significant reduction in life that occurs there or at any other SOC point within specification.

If you take it lower your are shortening the life of the battery for sure.

As an example, the difference in service life for a Trojan T105 between 50% DOD and 80% DOD is about 4%. Is "shortening" a battery's service life by 4%, contrasted to all the other factors that influence service life really significant?

If you take it down to near zero even once

Which isn't something that can happen in use, because most devices you'd be operating cease function below 10V. Not that you can't accidently leave a load on that kills a battery down to zero, but you can't practically operate a battery below 10V so >80% DOD is not a risk or a problem in typical use.

Typical lead acid battery are good for about 500~600 charge cycles at 50% depth of discharge.

Twice that for deep cycle batteries. Trojan T105 has about 650 cycles to 80% DOD, 1200 for 50% DOD.

Mark B.
Albuquerque, NM

[az99]

Originally Posted by JHinman

What I do with mine - number one is state of charge of my batteries. Number 2 is the rate of consumption of power. Early on I used it to determine how much power different items use. Number 3 is to verify that everything is shut down when I leave the rig, by seeing that power consumption is zero.

I have the temperature monitor, but have never seen temperature get out of hand.

Every time I open the app I have a red alert for Mid Range Power. The app shows me 100% mid point deviation. Any idea what it is wrong or how to fix it?

[JHinman]

Originally Posted by az99

Every time I open the app I have a red alert for Mid Range Power. The app shows me 100% mid point deviation. Any idea what it is wrong or how to fix it?

How are your batteries set up, and how is your monitor configured?

[az99]

Originally Posted by xc-mark

I would say even if it is Bluetooth it's not going to help you. My smart shunt barely transmitted 6' and inside and maybe 25' outside the coach.

Mine won't connect inside the coach even when it is 3' away. It connects outside the coach quickly.
There is plenty of cable to move it inside but I hate having to use an app for everything. Too bad it is not integrated into the Firefly.

[JHinman]

Originally Posted by az99

Every time I open the app I have a red alert for Mid Range Power. The app shows me 100% mid point deviation. Any idea what it is wrong or how to fix it?

Do you have batteries connected in series? I think that is the configuration where you need to monitor the midpoint deviation. For parallel batteries your power lead should be connected to port B1, not B2. There is a setting for what the auxiliary input B2 is for, and that should not be set to MID. Mine is set to TEMP for temperature monitor. I don’t know what it should be set to if that port is not used.

If your batteries are in series I have no experience with the mid-point monitoring.

[az99]

Originally Posted by JHinman

Do you have batteries connected in series? I think that is the configuration where you need to monitor the midpoint deviation. For parallel batteries your power lead should be connected to port B1, not B2. There is a setting for what the auxiliary input B2 is for, and that should not be set to MID. Mine is set to TEMP for temperature monitor. I don’t know what it should be set to if that port is not used.

If your batteries are in series I have no experience with the mid-point monitoring.

No they are not in series. I don't think it should be connected either as they just have it on the other end of the bank where it goes to the jump start relay for the chassis battery. If I pull the fuse it still reads 100% deviation.
I found it in the app and removed it and B2 wire.
Thanx

[JHinman]

Originally Posted by az99

No they are not in series. I don't think it should be connected either as they just have it on the other end of the bank where it goes to the jump start relay for the chassis battery. If I pull the fuse it still reads 100% deviation.
I found it in the app and removed it and B2 wire.
Thanx

That B2 port can be used for three different things - mid-point monitoring of batteries in series, battery temperature monitoring, or monitoring the voltage of a separate battery. It can do only one of those things, and the device setup must identify the proper use.

Could it be that the intent is to monitor your chassis battery voltage, and the BMV monitor is just set to the wrong function?

The device can trigger a relay when certain alarms are set for that B2 port. That is outside of my experience.

To set these monitors up, you need both the installation guide and the user manual. The user manual has descriptions, and the installation guide has the diagrams.

[az99]

It seems to have a lot more functions than I need. The app did show that the coach still has a 5 Watt draw even with the salesman switch off. The truck batteries are monitored on the Firefly.
I changed the settings per the videos and hopefully I am good to go.

I remember the good old days when all this was easy. When the lights got dim the house battery needed charging and if you want 110V you start the generator.

[JHinman]

Yes, the Victron monitor shows a lot more information than I need, and all of the relay things are beyond me. I think the monitor can be set up to start a generator when the battery SOC gets low. If the monitor would lift my Honda generator out of my truck and plug it in too, that would be great!