question

fredericmora avatar image
fredericmora asked

VE Network capability with BT dongle??

Hi, I have two solar controllers charging the same battery bank. One of the controller is a Smart solar, the other is a Blue Solar with newest version of BT dongle. I understand I can't do synchronized charging with the BT dongle, but why can't the Smart solar controller (+BT dongle) get the Charging Current from the BMV702 with BT dongle? I can get it on the SmartSolar. This is very annoying as there are big differences of Absorption durations between the two controllers. And half of the PV array switch to Absorption too early.


thanks

MPPT SmartSolarVE.Direct Bluetooth Smart Dongle
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

1 Answer
Alexandra avatar image
Alexandra answered ·

@Frederic.mora

https://www.victronenergy.com/media/pg/20723-VE_Smart_Networking-html5/en/limitations.html

https://community.victronenergy.com/questions/62310/synchronized-charging-not-working-for-2-mppt-10050.html

If one is sensing that there is less current drawn from it then it will switch charge states as it is designed to do, and this is one piece of data that is not transferred over BT dongle as far as I know.

Is the performance of the batteries compromised at all? What type of battery do you have? Check with a meter for peace of mind, but to be honest we have a system with a mix of the two types and have never had over or undercharging issues and no they are not synchronized.

2 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

fredericmora avatar image fredericmora commented ·

Thanks for your answer. It can potentially undercharge the battery as one Controller (with the BT dongle) switches too early to Float. Once in Float, this panel is not producing anything as the second panel is doing all the work to try to keep up with Absorption voltage. When a load kicks in, that one panel that is still in Absorption might not have enough power to maintain voltage and that extends charging time. Meanwhile, the second panel in Float is not producing anything as it is waiting for the voltage to drop below the float voltage threshold. Big loss of system overall capacity. It would be interesting to know if someone managed to adjust settings to reduce the impact of the lack of synch.

thanks

0 Likes 0 ·
Alexandra avatar image Alexandra ♦ fredericmora commented ·

@Frederic.mora

In absorption stage the batteries will not be drawing much current for charging. But the voltage is being held higher. Here is an example of a charge curve, bear in mind the stages change according to battery type set

screenshot-20201112-172556.jpg

What batteries do you have? Absorption is quite important on lead based batteries and some passively balanced lithiums.

You can set your float voltages higher if capacity is an issue and your battery specs allow it.

0 Likes 0 ·
screenshot-20201112-172556.jpg (74.7 KiB)

Related Resources

MPPT product page

VictronConnect manual

PWM or MPPT

MPPT calculator

MPPT codes

Additional resources still need to be added for this topic