Our Truck Camper solar

[RandyP]

Also found this

Amazon.com

 

[TCgreg]

I'm sort of liking the idea of the inverter LVCO handling the AC side. The Victron Battery Protect on the DC side and the Thor as a redundant backup in case either the inverter or victron fail. Since it has it's own voltage sensing circuit it operates independently of everything else in the system. A safety net.

My deepest concern for my battery is falling off the low voltage side due to accidentally leaving something on.

 

[RandyP]

I'm sort of liking the idea of the inverter LVCO handling the AC side. The Victron Battery Protect on the DC side and the Thor as a redundant backup in case either the inverter or victron fail. Since it has it's own voltage sensing circuit it operates independently of everything else in the system. A safety net.

My deepest concern for my battery is falling off the low voltage side due to accidentally leaving something on.

"The Victron Battery Protect on the DC side", that leaves the Victron BP in the dc circuit subject to a reverse current when battery charging thru the magnum Inverter/charger.....I know you do not charge the batteries that way often because the solar keeps the system charged well. I guess you could rely on the solar converter to cutout the solar charge on battery high voltage and low voltage set points ? The stand alone Thor BP looks like a good LV BP backup plan.

 

[RandyP]

Another question. You have two 300AH 12v batteries in parallel for 600AH total.
Looks like I could build a 4P/4S cell battery for 400AH ?
I don't think I need the 600 AH, and cannot fit as many solar panels on my roof as you did to support a 600AH battery.

 

[TCgreg]

Another question. You have two 300AH 12v batteries in parallel for 600AH total.
Looks like I could build a 4P/4S cell battery for 400AH ?
I don't think I need the 600 AH, and cannot fit as many solar panels on my roof as you did to support a 600AH battery.

Sure. You can size it anyway you want. 100, 200, 300, 400, 500 etc. 12v, 24v, 36v, 48v. Lots of options.

A 400ah bank is plenty for most things in a TC. One nice thing about lithium is that you don't need to worry about having enough solar as you don't need regular full charges or equalization. Some people run with large lithium banks charge at the campground then boondock a few days with no solar at all. Lot's of ways to go. One thing for sure is the smaller the battery bank the less you will spend.

 

[TCgreg]

"The Victron Battery Protect on the DC side", that leaves the Victron BP in the dc circuit subject to a reverse current when battery charging thru the magnum Inverter/charger.....I know you do not charge the batteries that way often because the solar keeps the system charged well. I guess you could rely on the solar converter to cutout the solar charge on battery high voltage and low voltage set points ? The stand alone Thor BP looks like a good LV BP backup plan.

The victron would be between the battery bus and the dc load. No charging through it. The DC for the AC inverter would be between the inverter and the battery and not through the Victron BP.

 

[RandyP]

The victron would be between the battery bus and the dc load. No charging through it. The AC would be between the inverter and the battery and not through the Victron BP.

So the AC would turn off ac to the inverter at inverter DC low voltage set point ?

 

[TCgreg]

So the AC would turn off ac to the inverter at inverter DC low voltage set point ?

Not sure I know what you mean. The BP would be between the battery and the DC distribution panel. Unless you were back feeding a DC circuit current would only be flowing one way through the BP. Any dc current the inverter charger is making would flow to the battery and then on to the DC circuits. AC is on its own side. The inverter is taking DC power and feeding the AC side of the camper.

 

[RandyP]

Got it, ac output side not ac input side, daaah !

 

[RandyP]

Read something about NOT using the ac ON OFF relay for switching if the current is greaterr than 30A. Said to turn the load off before using the relay ? I'll look for that again.

 

[TCgreg]

Still confused.

Not using alternating current for anything on the DC side. The only place they co-exist is in the inverter charger. The LVCO for the inverter is on the DC side. Battery disconnects to inverter due to low voltage (THOR) = no ac power from inverter = ac LVDC. Also Inverter charger has it's own LVDC feature.

When I say LVDC on the AC side I only mean dc power from the battery to the inverter. VS. LVDC on the DC side to the DC house circuits where a battery can be over discharged due to a dc load where an inverters LVCO wouldn't protect it.

 

[RandyP]

Read something about NOT using the ac ON OFF relay for switching if the current is greaterr than 30A. Said to turn the load off before using the relay ? I'll look for that again.

found it in the magnum controller manual, but do not think it applies here,..
"Stuck Relay – This fault message displays when the inverter is “inverting”, but the internal
AC pass-thru relay that should be open while inverting, is closed.
Remedy: The AC pass-thru relay is most likely stuck. A relay usually sticks because
of damage to the contacts from trying to handle higher currents than that for which
they are rated. This is usually caused by not protecting the relay from handling high
continuous currents, or by switching high current inductive loads. The internal relay
contacts are rated to handle 30 amps AC continuously and should be protected with a
breaker sized no larger than 30 amps. If you are connected to an AC source (grid or
generator) and running large inductive loads (i.e., pumps, motors, etc.,) on the inverter
output, turn those particular loads off prior to removing the AC input source. This fault
requires an inverter or power reset to clear."

 

[TCgreg]

Yea, that's all inside the inverter charger. I shouldn't ever be exposing our inverter charger to more than 30 amps AC loads. The 30 amp breaker on the shore should pop at 30 as well as the 30 amp main in the camper. You could install a separate 25 amp ac breaker before the inverter charger if you were concerned and limit yourself to that but I wouldn't concern yourself.

This isn't related to the DC side of the RV for protecting the battery from being over discharged.

 

[RandyP]

There are a few ways you could trigger a solenoid disconnect by voltage. I am leaning toward buying one of these. Not very creative and pretty expensive for what it is but looks like it would do the trick. They make 80 and 200 amp kits as well.

https://thorpowerproducts.com/product/thi-lvd-500-kit/

I did buy that kit item, worked for a few months. Draws about 0.5 A continuous. Gets hot because it is always energized unless battery goes below 12v.

Recently it has developed a resistance between battery term points that creates a voltage drop across the device. Cleared this one time, energize/deenergize it multiple times (10) repeatedly listening to it operate. Then it made up good and passed current as expected.

Even more recently it has failed open, still clicks when energized, but not functioning correctly, voltage drop across device when battery is at >12v. I would not recommend this device as a undervoltage protection device for a LiFePO4 battery.