Victron Multiplus II and Genset Issue

[JackConnick]

I can't get my Victron Multiplus II 50/3000 on my boat to switch from Storage mode and charge off my generator at more than 38 amps or so. It's set to accept 50 amps shore (I don't have it wired to a separate gen circuit - switch it manually).
I have a 5.5KW generator and 600ah of Lifeline AGM batteries. When I run my engines, my alternators kick out 90-100amps when the batteries are down.
Why doesn't it go to Bulk/Absorb/ modes? Batteries are 200ah low, ie at around 12.7v if I turn off the generator. The system says they are at 13.12v with gen on, is there a setting to change?

 

[RobertLeatch]

Have you tried turning off the Storage Mode setting on the Charger tab of VeConfigure?

 

[rslifkin]

Personally I don't like the storage mode feature, so I just keep it turned off. Then it'll at least charge at float voltage. If the voltage has dropped to (I think) 1.2 volts below the float voltage setting for a minute at some point since the last charge, then it'll start a new charge cycle of bulk, absorb, then float.

 

[JackConnick]

The issue I have is knowing how to turn it off.

 

[rslifkin]

It should be in the settings for the Multiplus. I'm not sure if you can do it from Victron Connect or if you have to use VEConfigure. Based on the VRM screenshot you have a GX device hooked up, so you should be able to use either tool from a PC remotely without needing to buy the adapter cable to connect directly to the Multiplus.

 

[tpbrady]

Victron chargers will not return to bulk mode unless the voltage drops below 12.3v if memory serves me correct. The only way to get it to go to bulk before that point is to turn the Multiplus off and then back on. That resets the charging algorithm. Victron insists this is the proper way for the system to work. My opinion it is stupid. When I am down to 70% SOC, it should go to bulk and not to absorptions and quickly to float. The solution is to turn it off and back on.

Tom

 

[twistedtree]

Victron chargers will not return to bulk mode unless the voltage drops below 12.3v if memory serves me correct. The only way to get it to go to bulk before that point is to turn the Multiplus off and then back on. That resets the charging algorithm. Victron insists this is the proper way for the system to work. My opinion it is stupid. When I am down to 70% SOC, it should go to bulk and not to absorptions and quickly to float. The solution is to turn it off and back on.

Tom

I agree this is undesirable behavior on many boats. I, like many others, run my generator for various things not directly related to battery charging - like making water, heating water, etc. When I need to run a generator for such an activity, I typically want to also opportunistically charge batteries while the generator is running. But the dumb-ass victron won't charge. Most chargers have a setting to control whether they always initiate a full charge cycle when AC power is applied, or whether they assess voltage and conditionally enter float instead. It sure would be nice if Victron had such a switch.

 

[rslifkin]

Victron chargers will not return to bulk mode unless the voltage drops below 12.3v if memory serves me correct. The only way to get it to go to bulk before that point is to turn the Multiplus off and then back on. That resets the charging algorithm. Victron insists this is the proper way for the system to work. My opinion it is stupid. When I am down to 70% SOC, it should go to bulk and not to absorptions and quickly to float. The solution is to turn it off and back on.

Tom

It's not a fixed 12.3v, it's a certain amount (1.2 or 1.3 volts I think) below the configured float voltage. That gets reduced to 0.1v below float when the Lithium mode is enabled.

Personally, I think that's one of the 2 big flaws in the Multiplus charge algorithm. The other is that you can't end absorb based on amps, only based on time. That's fine for lithium, but not ideal for lead.

Funny enough, neither of those issues is present in the charge algorithm on the Victron MPPTs. Those have an adjustable re-bulk voltage and can end absorb based on amps being accepted. But Victron has never brought that more flexible charge algorithm to the Multiplus family for some reason.

 

[SteveK]

Magnasine goes rebulk at 12.8V for LFP. Also power off/on restarts bulk. It also has a % feature I tried which when I set to 80% would not put SOC above 80%. I will have to try again to confirm as that can be used for storage I suppose.

 

[JackConnick]

I managed to install the ve configure app on my mac using "Wine" in Terminal. Then I was able to switch off the Storage mode and adjust charging voltages to what Lifeline suggested; Absorption voltage 14.30V, Float voltage 13.30V. Temperature compensation -13.0. It still went into Float mode and charging very slowly. I've changed the Absorption time to Fixed to 4 hours.
I have to say while you can adjust all these things, the MultiPlus II is way over complicated; it should just go into Bulk when you start to charge like the rest of their chargers. I have a Phoenix on my start bank that's much better.
Jack

 

[rslifkin]

I managed to install the ve configure app on my mac using "Wine" in Terminal. Then I was able to switch off the Storage mode and adjust charging voltages to what Lifeline suggested; Absorption voltage 14.30V, Float voltage 13.30V. Temperature compensation -13.0. It still went into Float mode and charging very slowly. I've changed the Absorption time to Fixed to 4 hours.
I have to say while you can adjust all these things, the MultiPlus II is way over complicated; it should just go into Bulk when you start to charge like the rest of their chargers. I have a Phoenix on my start bank that's much better.
Jack

The idea of not going back to bulk if the batteries haven't been drawn down is fine, the threshold just needs to be adjustable for it to work well. Having the feature without a way to tune it is a pain though.