Victron power assist programing help

nyoffgrid · January 6

Hey all,

I just bought this unit: https://www.victronenergy.com/upload/documents/Datasheet-MultiPlus-II-3kVA-2x120V-EN.pdf

I have a single 24v lifepo4 200ah battery. No solar panels - I charge with my honda genset 2200watt.

With my current inverter when my genset is on and powering the cabin plus charging the batteries - when the fridge compressor kicks in - the genset tries to ramp up quickly and that causes the inverter to disconnect the genset and discontinue the charging. After about 20 sec it will again switch to have the power from generator and charge batteries.

I read that power assist can help with this situation. Any advice on what parameters to set it to?

SumPower · January 8

Just did my first install of a multi plus II. So I am definetly not a seasoned Victron user.

Do you have a Digital Multi Control (DMC) 200 GX? A CerboGX ? Or the MK3-USB? To change settings.

The generator current limit can be adjusted with increments of 2 amps. The generator limit for small generators is recommended to be set at 70% of maximum amps of the generator.

So your gen @ 2200w/120v = 18.3 Amps --- Edit: Peak Rating

18.3 Amps x .7 = 12.83 amps

Edit: So the maximum recommened AC input current limit for your generator would be 12 amps per the DMC manual.

Max. current limit: set to 12 amps.

Edit: Max continueous rating of the 2200 watt genset is 1800 watts @ 15 amps

1800 / 120 = 15 Amps ; 15A x .75 = 11.25 A or 15 x .7 = 10.5 A

Edit: So the Max. current limit is: 10 Amps as it is set in 2 amp increments.

Turn on: Dynamic Current Limit. This allows the inverter to take over the load while the generator is ramping up. Once the generator ramp up is complete, the inverter and generator work together. This helps the generator to not stall out.

Turn on: Accept Wide Input Frequency Range

Wish I could be more help, but I am in the learning mode with Victron. My new go to solar equipment.

SumPower

BB. · January 10

Just an FYI... The Honda eu2200i rating is peak/surge output rating...

https://powerequipment.honda.com/generators/models/EU2200i

AC Output120V 2200W max. (18.3A), 1800W rated (15A)

1,800 Watts or 15 Amp max continuous rating (and 70% or 75% derating is what I suggest).

0.75 * 15 Amps = 11.25 Amps suggested "max continuous" rating for battery charging and/or other "constant loads" (such as irrigation pump, etc.).

-Bill

SumPower · January 10

Thanks BB, I edited my post above to reflect your attention to detail.

BB. · January 10

No problem... Specifications need to be read in "detail" to ensure that one is correctly interpreting them.

Also, technically, I have been using 80% derating--Gives one a bit more current/wattage and is a common derating for wiring/breakers/etc... (i.e., NEC derates breakers and wiring to 80% for continuous current flow--One should not run wiring/breakers at 100% of "printed" specifications...

If I recall correctly, Xatrex inverters (a few, some, all XW models?) would derates the incoming Mains/Genset programmed max current draw to 80%--I.el, if you programmed the Genset was a 30 amp current, the unit would draw no more than 24 amps.

For example, in North America, typical residential breakers are rated to not trip at 80% or less of current flow, and will trip (could be minutes/hours/etc.) at 100% or more current flow... (the specifications have lots of "wiggle room").

A 15 amp breaker:

15 Amps * 0.80 = 12 amps or less continuous current flow

For example, I was working on an apartment that had an electric water heater that used around 19 amps (at 240 VAC). And the building was constructed in 1950's (was quasi government apartments for military suppliers?) with a 15 amp breaker and 14 AWG wiring.

Never had any real problem with wiring or breaker tripping... Until 2010 or so... I choose to require with 10 AWG and a 30 Amp breaker to make it a one time fix, vs having to address an "possible" problem in the future. (note that different insulation types for wiring, ambient temperatures, conduit fill, etc. affect "rated" current capacity).

20 amp * 0.8 = 16 amp continuous current (on 12 AWG cable)
30 amp * 0.8 = 24 amp continuous current (on 10 AWG cable)

Who knows what people/electricians/code inspectors were thinking in the 1950s...

-Bill

nyoffgrid · January 21

Thank you so much for the great info. I installed it last weekend. I do have a question but will start a new thread

Victron power assist programing help

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