Setting up a new VictronConnect MPPT 75/15

[john61ct]

Originally Posted by KRMS

So this is the info form the manufacturer’s tech support

That is the seller / distributor, likely there is an OEM actual mfg like Johnson Control Inc JCI, they just relabel it.

> I’d be delighted to get what is needed (but might need help in framing the question(s).

What I posted is as clear as I know how to make it.

Main goal "how do you define 100% Full?"

This is what I and some charge source regulators call the endAmps spec,

IOW "as trailing amps decline, what is the point where you know they are 100% Full?"

For example, many AGM spec ".005C", which for a 520AH bank would be 2.6A

So if they say they don't know, ask who the actual manufacturer is, and can they pass on their TS contact info.

Or just use that .005C spec, it's pretty generic.

[mitiempo]

Originally Posted by john61ct

Pretty sure the smaller Victrons only do internal temp sensing, why I said put close to the bank.

That is why the temp sensor should be added. Temp is often not the same at controller and batteries. The temp sensor also takes into account voltage drop due to wiring.

https://www.youtube.com/watch?time_c...&v=v62wCfXaWXY

[billknny]

Originally Posted by mitiempo

That is why the temp sensor should be added. Temp is often not the same at controller and batteries. The temp sensor also takes into account voltage drop due to wiring.

https://www.youtube.com/watch?time_c...&v=v62wCfXaWXY

The OP is correct, you CAN NOT add a temperature sensor to that controller. If you think about it, it really isn't needed, if the controller is in the same general ambient environment.

The output from that controller is far too small to have a significant effect on internal battery temperature, even running at full output. Now a 100 amp alternator or mains charger... that is a different story. They can add a significant amount of heat to the battery, and generally must be mounted in an environment (e.g., the engine room!) that is very different than the battery box--hence the need for a remote sensor.

I check my battery temps regularly as part of my routine maintenance. They are never more than 1 or 2 degrees C from ambient unless there is a serious problem.

My large shore and genset powered chargers all have temperature sensors because they are in the engine room, a very different thermal environment form the area around the battery. My solar controller is mounted within a meter of the batteries, and a remote temperature sensor would be a waste.

[CarlF]

I have two of those Victron units and can confirm that there is no place to attach an external temp sensor and none is offered as an option.

But I also agree that the internal temp sensor if likely fine if the controller is mounted near the batteries.

I think folks are getting a little carried away with the voltage concerns. Solar panels don't put out the sort of amps that a 14.6 or 14.8 absorption voltage for a large bank is going to be a noticeably faster charge than 14.4 or even 14.2v. Nor are you going to overheat a big bnk with 15 or 20 amps of solar that's only on 8 hours a day - and zero volts the other 18 hours.

I am a little surprised that the OP's AGM's have a 13.8v float voltage. Lifeline's recommended float voltage is 13.3V. Firefly's is 13.4V. Does anyone know why AGM batteries that share basically the same chemistry have such different recommendations?

[mitiempo]

Originally Posted by CarlF

I have two of those Victron units and can confirm that there is no place to attach an external temp sensor and none is offered as an option.

You are correct - there is no place to connect a temp sensor to a Victron Smartsolar controller. It is not necessary because it is wireless. Look at the short video in the link I provided.

The red and black wires shown below go to the battery terminals. Wireless to the Smartsolar controller which the op has.

We are Victron distributors and retailers in Victoria B.C. and it is available as an option.

[john61ct]

Originally Posted by billknny

The OP is correct, you CAN NOT add a temperature sensor to that controller. If you think about it, it really isn't needed, if the controller is in the same general ambient environment.

The output from that controller is far too small to have a significant effect on internal battery temperature, even running at full output. Now a 100 amp alternator or mains charger... that is a different story. They can add a significant amount of heat to the battery

That is not the issue.

Automatic temperature compensation is not needed because of temp changes caused by charging.

Voltage gets adjusted as ambient temp changes, from day / night, season, geographic location and the weather.

[john61ct]

Originally Posted by CarlF

I think folks are getting a little carried away with the voltage concerns. Solar panels don't put out the sort of amps that a 14.6 or 14.8 absorption voltage for a large bank is going to be a noticeably faster charge than 14.4 or even 14.2v.

The point is not faster charging, it is optimum care for the battery.

> Nor are you going to overheat a big bnk with 15 or 20 amps of solar that's only on 8 hours a day - and zero volts the other 18 hours.

And no one knowledgeable is concerned about overheating as a result of solar charging.

> I am a little surprised that the OP's AGM's have a 13.8v float voltage. Lifeline's recommended float voltage is 13.3V. Firefly's is 13.4V. Does anyone know why AGM batteries that share basically the same chemistry have such different recommendations?

Because they are only "basically" the same.

The construction and chemistry of different batts varies widely even within one type.

Firefly's needs are very different. Treat them like Lifelines and you will drastically reduce lifespan

[john61ct]

Originally Posted by mitiempo

You are correct - there is no place to connect a temp sensor to a Victron Smartsolar controller. It is not necessary because it is wireless. Look at the short video in the link I provided.

The red and black wires shown below go to the battery terminals. Wireless to the Smartsolar controller which the op has.

We are Victron distributors and retailers in Victoria B.C. and it is available as an option.

Wow, that is news to me.

Did BlueSolar models use those as well if fitted with the dongle?

When did that product reach the US?

[mitiempo]

Originally Posted by john61ct

Wow, that is news to me.

Did BlueSolar models use those as well if fitted with the dongle?

When did that product reach the US?

They have been available for a few months. Yes it works with the dongle.

In many cases the controller is installed close to the batteries but in a separate compartment with very different temperatures.

In my case the batteries will be beside the engine in the cockpit locker while the controller will be inside the cabin on the other side of the bulkhead.

[sailcrazy]

Following

[john61ct]

Super, that's always been an Achilles' heel with the low end Victron units for demanding customers.

I've even heard they don't handle temp comp well by design even if ambient is same as batt temp.

Anyone testing actual performance with these please post results