Victron MPPT 100/20 Q's

[SLOwr]

Hi all, a couple questions on this charge controller:

1) I see it auto-senses batter voltage (12/24/48). In my system design, it's more advantageous for me to put 2 lead-acid batteries in parallel at 12v than in series at 24v, so I get more AH's. Is there any disadvantage to 12v (parallel)? For example, is there an efficiency loss?

2) does this model controller need a relay added, so it's able to disconnect the load if the battery is too discharged? This is mentioned in the data sheet, and is a bit surprising it wouldn;t have a built-in relay. If it's needed, how do I interface the relay and what kind is needed, etc? (details)

3) I assume the optional battery voltage sensors display their data on the mobile app for the controller, correct? Do they have their own bluetooth connection, or use the controller's? If they connect together via Bluetooth, is a BT connection still available for my cell phone?

 

[sunshine_eggo]

Hi all, a couple questions on this charge controller:

1) I see it auto-senses batter voltage (12/24/48). In my system design, it's more advantageous for me to put 2 lead-acid batteries in parallel at 12v than in series at 24v, so I get more AH's. Is there any disadvantage to 12v (parallel)? For example, is there an efficiency loss?

You get more Ah, but you don't get more storage.

12V * 100Ah * 2 = 2400Wh

24V * 100Ah = 2400Wh

Higher voltage benefits from being able to handle a larger array.

12V: 14.5V * 20A = 290W
24V: 29V * 20A = 580W
48V: 58V * 20A = 1160W

For any given power, higher voltage batteries require less current and need thinner wires.

2) does this model controller need a relay added, so it's able to disconnect the load if the battery is too discharged? This is mentioned in the data sheet, and is a bit surprising it wouldn;t have a built-in relay. If it's needed, how do I interface the relay and what kind is needed, etc? (details)

It automatically disconnects its own load ports, but you can use an external relay to disconnect loads that are larger than the MPPT can handle.

3) I assume the optional battery voltage sensors display their data on the mobile app for the controller, correct? Do they have their own bluetooth connection, or use the controller's? If they connect together via Bluetooth, is a BT connection still available for my cell phone?

If you're referring to the Smart Battery Sense (SBS) or a Smartshunt or a BMV-712, all three devices can be put into a VE.Smart network with the MPPT to feed the MPPT direct voltage, current (not the SBS) and temperature (if probe installed on shunt).

All BT devices in a VE.smart network can still be displayed/configured on VC.

VE.Smart Networking

www.victronenergy.com

Please be advised that this controller is marginal for use on a 48V battery. The 100V limit is NEVER EXCEED in any circumstances and allowing for cold temperature effects (colder temps = higher voltage). It is very difficult to get a suitable Vmp value, 72V, on this controller as 72Vmp is going to be over 90Voc. At that point, if you drop below freezing, you'll exceed 100V.

 

[Rocketman]

Just to explain one item Sunshine said…

VC - Victron Connect is the app on my phone that has all the info for me about the mppt.

It will continue to use the VE.smart network (the Bluetooth connection) between other devices- Smartshunt,etc. that has no effect on the Victron connect app

 

[sunshine_eggo]

too... much... blue.... in my veins... can't speak... naturally....

 

[Suijkerbuijk]

The victron 100/20 for 48 battery you need
3x22volts panels (66volts +20% winter = 79 volts )
This is only panel setup that you can use .

Thare are 39 cells panels with 26.5volts output
But that is 3x26.5 plus 20% winter 95.5 volts .
Its just fit on this mppt .
If your are in a country with soft winter than its 15% if you are in a country with no winter than 0% on the volts in the calculation.

Its off topic .
But you never know if somebody in the future looking it up and see this topic .

 

[Bastichy]

You get more Ah, but you don't get more storage.

12V * 100Ah * 2 = 2400Wh

24V * 100Ah = 2400Wh

Higher voltage benefits from being able to handle a larger array.

12V: 14.5V * 20A = 290W
24V: 29V * 20A = 580W
48V: 58V * 20A = 1160W

For any given power, higher voltage batteries require less current and need thinner wires.



It automatically disconnects its own load ports, but you can use an external relay to disconnect loads that are larger than the MPPT can handle.



If you're referring to the Smart Battery Sense (SBS) or a Smartshunt or a BMV-712, all three devices can be put into a VE.Smart network with the MPPT to feed the MPPT direct voltage, current (not the SBS) and temperature (if probe installed on shunt).

All BT devices in a VE.smart network can still be displayed/configured on VC.

VE.Smart Networking

www.victronenergy.com

Please be advised that this controller is marginal for use on a 48V battery. The 100V limit is NEVER EXCEED in any circumstances and allowing for cold temperature effects (colder temps = higher voltage). It is very difficult to get a suitable Vmp value, 72V, on this controller as 72Vmp is going to be over 90Voc. At that point, if you drop below freezing, you'll exceed 100V.

this answer is awesome! thanks very much.. and im loving the fact i live in Jamaica more now.. based on his reply when i finally have enough money i can go 48v no prob as i never have snow.

 

[soylentgreen]

The Victron 100/20 has a Load output, but it's limited to 20A (when running 12V or 24V batteries) or 1A (when running a 48V system).

So if you wanted to control bigger loads, you'll definitely need other use the load output to control a bigger relay.

Here's the data sheet:

https://www.victronenergy.com/upload/documents/Datasheet-SmartSolar-charge-controller-MPPT-75-10,-75-15,-100-15,-100-20_48V-EN.pdf

I have a 100/20 installed in my RV, and am happy to answer further questions about it.

 

[soylentgreen]

Another consideration - the PV voltage must be +5V higher than the battery voltage for the MPPT to start charging. Normally not a problem, but if you had some weird configuration (such as a 24V battery, hypothetical 28V solar panels) it might not work.

 

[Bastichy]

hmm.. i have 800w of foldable panels in series - that comes in at 90v-its usually registering 74v.
thanks for your replies!