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-   -   Victron 712 Smart (http://www.irv2.com/forums/f54/victron-712-smart-470689.html)

EJ_Clemson 11-30-2019 05:04 AM

Victron 712 Smart
 
Hey guys and gals,

Can this battery monitor act as a sort of charge controller? I have installed 2 100ah lithium batteries, and I would like to charge them to only 90% without having to keep an eye on my $40 Aili battery monitor, and then hitting the breaker to turn off my progressive dynamics lithium charger.

I guess what I'm asking is if this monitor can be programmed to control charge voltages? For instance, can it stop my charger from sending volts when my batteries read 13.3 volts? And then be programmed to enter in a float mode?

I've read Victron's manual, but I'm still not clear if this can specifically be done. TIA!

TomeAR 11-30-2019 06:23 AM

Why would you want to limit the charging of your batteries from what the PD charger/converter is designed to do? Did you also install a Li-specific Battery Isolation Manager (BIM), too? BTW - more info on your setup would be good to know.

dp7 12-01-2019 02:46 AM

Quote:

Originally Posted by EJ_Clemson (Post 5057609)
Hey guys and gals,

Can this battery monitor act as a sort of charge controller? I have installed 2 100ah lithium batteries, and I would like to charge them to only 90% without having to keep an eye on my $40 Aili battery monitor, and then hitting the breaker to turn off my progressive dynamics lithium charger.

I guess what I'm asking is if this monitor can be programmed to control charge voltages? For instance, can it stop my charger from sending volts when my batteries read 13.3 volts? And then be programmed to enter in a float mode?

I've read Victron's manual, but I'm still not clear if this can specifically be done. TIA!

My understanding is that this only a monitor that reports battery voltage/SOC and does not provide any charge control.

C.Martin 12-01-2019 05:30 AM

The BMV-712 can control a charge relay in charge mode. Download the free Victron Connect app...go into Demo Mode...and apply the BMV-712. Under settings , you will see relay mode. Not sure if this is what you really want, but it might work as a way to cut off a charger.

It is not a charge controller...you really asked two questions. Cutout at 90%...the BMV might help with. The going to a set voltage and entering float...is a charge controller function...many allow custom voltages to be set by user.

I'm not sure that you will see reliable results with voltage alone. The curve is pretty flat in comparison to lead acid batteries.

EJ_Clemson 12-01-2019 09:55 AM

Thanks Everyone.

It is my understanding that lifepo batteries will last longer if only charged to 90% and discharged to maybe 20% or so. They're often times where that kind of usage works be fine for me so I figure why not try to do it.

Currently my progressive dynamics PD4045LICSV charger will simply throw 14.6 volts the entire time until my two renogy lithiums are at 100% or 13. 6-14.4 volts. Then it seems like the batteries BMS stops the voltage from coming through.

I would simply like to be able to stop the voltage/charge from coming through when the batteries hit 13.3 or so.

It's not a huge deal really as I already purchased and installed the Aili battery monitor, but sort of regret not getting the 712 just to mess with it.

Also, if I had to do it all over again I'd get a charger that can actually be programmed, but I was led to believe my current charger is what is perfect for lithiums. Honestly, there is still a lot of misinformation out there in the world of lithium iron batteries.

I just find it disturbing to pump a constant 14.6 volts to my batteries and rely on the BMS to constantly allow or not allow voltage to come through. I currently charge my batteries when plugged in, and if still plugged in at a friend's house or campground, ill turn my charger off and run on the little DC power that's needed. Ill go to about 20% and then turn the charger back on. Just a bit of a pain to constantly monitor the way I want to run my batteries.

C.Martin 12-01-2019 11:51 AM

I would look at Victron chargers and charge controllers. Many can be networked to accept input from the BMV-712.

Another method is solar...it cycles (daylight)...and Victron SmartSolar controllers can be programmed (via Victron Connect smartphone app) to your exact parameters. I have seen Lithium/Solar setups that keep the daily charge cycle in the sweet spot...not going 100% everyday, but hovering in the 80 to 90% region before the sun goes down each day. You do need enough battery to make it thru the night...as without using the shore power charger, it will discharge based on residual loads overnight.

Itinerant1 12-01-2019 01:30 PM

OP, you realize that the bms is there to protect the battery (cells) as a last line of protection, shut down the battery to protect itself.

Programmable charge devices with proper cut off is the first line of protection. Relying on human interaction will only take one distraction to cause an issue.

Coming full circle, having the bms should protect the battery when the time comes and you get sidetracked. ;)

EJ_Clemson 12-02-2019 05:37 PM

Quote:

Originally Posted by Itinerant1 (Post 5059180)
OP, you realize that the bms is there to protect the battery (cells) as a last line of protection, shut down the battery to protect itself.

Programmable charge devices with proper cut off is the first line of protection. Relying on human interaction will only take one distraction to cause an issue.

Coming full circle, having the bms should protect the battery when the time comes and you get sidetracked. ;)

That's exactly why I'm looking into the 712. It sounds to me like its programmed to charge batteries to 90%, but I'm trying to get real world usage information. I'm sure I'll email Victron sooner or later. Enjoying the RV at the moment.

Itinerant1 12-02-2019 07:43 PM

I'm surprised that the Victron user haven't replied with more help, to me it looks like a little monitor to interact with other Victron devices to get all the benifits.

astrocamper 12-03-2019 10:53 AM

My BattleBornBatteries require periodic 100% charging to balance the cells. I also want it to charge to 100% periodically to sync the BMV-712 so it shows as 100% charge. There can be some drift in the charge percentage display if it always stays well below 100% SOC. I only see this in the winter months when my panels get a lot of snow.

Rocketman3 12-12-2019 12:03 PM

You spent a lot on those lithium batteries - spent a little bit on a great charger so you can control the charge cycles like you want. I like Victron products, the BMV-712 might work with the relay cutting of the charge - but I would get a unit that I could program exactly how I want.


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