question

blskevin avatar image
blskevin asked

Managing multiple charging sources for max charge current

I have a set of FLA batteries on my boat that can accept 200 amps of charge current at 12V in bulk mode.

For charging underway I have a 150 amp alternator and am also expecting to add solar in the near future.

If I use a inverter/charger (for example 2 miltiplus units or a single Quattro) will the Cerbo controller back off the charge current to that of a programmed acceptance rate for the batteries?


I want the capability to charge even if not underway at my full 200A but do not want to exceed my batteries charge current acceptance rate.


Thanks!

battery charging
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2 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

You will need a GX device and use DVCC with the "charge current limit"(4.4.1).
With this feature the GX device will limit the charge current to the set value, solar power is prioritized over the grid/generator.
Works only with Victron MPPT charge controllers!
The alternator current can't be limited!

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blskevin avatar image blskevin commented ·

Thanks!

I have a Cerbo GX controller and a BMV 712 battery monitor on order right now.

Do I need a GX inverter/charger as well? The reasonI ask is that Ido not see the GX capability in a 120V AC 12V DC inverter/charger. Am I missing a model out there?

Thanks for the link to the DVCC paramater. That is exactly what I need!


Reading further I do have a problem though. The DVCC current limit only applies to Victron devices. Even though I have a Victron Battery monitor the engine alternator’s output will not be counted against the total allowable charge current.


I need to somehow solve this. Perhaps it will be in a future firmware realase because it seems east to use the BMV as the charge current number.


Is there a Victron device that I could route my engine alternator charge current through that would work?


Is there a contact closure I could provide to the Cerbo GX that would disable the charging function? I could tie this to the engine running signal for example so that when the engine is running the inverter/chargers do not charge the batteries at all.


Thanks again!

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ blskevin commented ·

You don't need a MultiPlus II GX if you have a Cerbo GX.
The MultiPlus II GX is currently only available for 24/48V DC and 230V AC.

Currently there is no way to also take the alternator current into the calculations. Maybe some time in the future.

You could use the "alternator running" signal to trigger a relay that is connected to an input (Temp./AUX1/AUX2) of the Multi and program an assistant (Charge current control) to disable (or reduce the current) the charger of the Multi.

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blskevin avatar image blskevin Matthias Lange - DE ♦ commented ·

Thanks! this is something I’ll be playing with. I’ll start with your suggestion and see where it takes me.


Another option would be to install a relay in series with the AC input to the inverter/charger. That relay would open the circuit if the engine is running.


The goal is to be able to charge my batteries at the max rate possible while taking advantage of my engine alternator while underway.

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blskevin avatar image blskevin Matthias Lange - DE ♦ commented ·

I have been reading the Cerbo manual and cannot find any mention of an “assistant”.


Is this a rule I can set up? How do I learn about assistants, and how to enable them?


Thanks!

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ blskevin commented ·

Assistants have to be 'installed' into the Multi using VEconfig.
https://www.victronenergy.com/live/assistants:start
https://www.victronenergy.com/live/drafts:veconfigure
https://www.victronenergy.com/blog/2017/02/10/instructional-video-for-ve-configure-3/
https://www.victronenergy.com/live/vrm_portal:remote-veconfigure

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blskevin avatar image blskevin Matthias Lange - DE ♦ commented ·

Thanks very much! You have been vewery helpful and gotten me off my feet with this new to me product line!

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blskevin avatar image blskevin blskevin commented ·

I have loaded the configuration tool and have added the charge current control assistant.


Install a 12V relay coil tied to the ignition circuit on my engine. When the ignition is on the N.O. contact of the relay closes, causing zero volts on the Aux 1 input of the inverter/charger. With the ignition off the relay is open causing the pull up resistor in the Aux1 input to reach approx 2 volts.

The assistant sets the max charge current at 100 amps when the Aux input is ≤ 1V representing the engine running.

It sets the charge current to 200A when the Aux1 input is ≥ 1.5V representing the engine off.

This provides for full capacity charging when running on the generator, and a lower capacity charging when the engine alternator is available.

Thanks again for your help!

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stevomyatt avatar image stevomyatt blskevin commented ·

@blskevin@Matthias Lange - DE this is creative thinking, well done!

Thanks very much for the info! I have been searching for a solution to this also. I am fitting out a van and will have a 100A alternator (with controller) along with smart BMS batteries connected to a cerbo gx with a multiplus II and MPPTs.

It would be handy to use a BMV to report the alternator current and therefore let the cerbo dynamically change the max charge current of the multi and MPPTs.

Does the assistant change the charging current on the multi only, or all devices connected to the cerbo?

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blskevin avatar image blskevin stevomyatt commented ·

I think the assistant is a program that resides in the multiplus, so it will only change that device.

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gertjand avatar image
gertjand answered ·

Look into the alpha pro alternator module. It can switch of the magnetic field of the alternator via the be.bus bms.

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