My 16,000 BTU marine air conditioner is having trouble start when I am on the generator , Onan 5KW 120Volts. If I switch the MultiPlus to Charge Only it works the AirCon, but not the Heat function. The Onan is plenty for the job. All works good on Shore Power. Does not work on the inverter very well. Engine must be running.
Do I have a wrong setting somewhere?
Tony
Thanks
Hi Tony
Gensets are always fun to set up correctly. While yours may be “plenty” for the job, bear in mind that as well as supply the load, the Multiplus may also ask it to charge batteries at the same time.
And when the Multi switches it in, it may not be able to wind up fast enough, then the Multi can reject it for off-spec power.
There’s some general stuff here… MultiPlus Generator FAQ [Victron Energy]
Look at the Dynamic Current Limiter (almost always necessary) for soft switching in of the genset. And experiment with the Multi’s Input Current Limit, like start a bit lower and work up. This ICL can be set up for easier changing with other options than VEConfigure. The Multi’s Power Assist will take up the slack as necessary, so you’re actually blending genset and inverter power at times.
There’s a sweet spot there somewhere. Good luck finding it, but come back if you need…
Thank You John, I Will experience with those options and let you know how it turns out. Have a great weekend.
Since “16,000 BTU” doesn’t really give much insight on the AC power draw: can you look up the AC’s power draw for AC and Heat function ?
As @JohnC said, you’re probably somewhere in limbo with the Current Limit / Boost Factor.
What kind of batteries and what type of Multiplus are you using ?
An AC unit tends to have a pretty hefty power draw (especially in Heat mode) so just maybe your Multi or batteries might not be up for the job of running it for a long time.
Thanks Bart,
My system consists of Multiplus 12/3000/120
5 AGM Batteries CCA 880 , Capacity Amp Hrs @ 20 ratet = 105 A
Footnote, I believe my starter battery is tied in to the house, since extended time on the inverter I have to use the Parallel switch to start boat motor.
Generator is a ONAN 5KW very low hours.
Domestic Air Con: AC mode 10.3 amp Heat mode 13.4
I believe the surge at start of the AC or Heat is the culprit. That is, while running the generator. No problem on shore power. Air conditioner will not run at all either cool or heat mode while on inverter. (Even while underway with the engine running.)
Thanks Bart and all.
Tony
In my previous RV I was using the same inverter to run a 15K Coleman rooftop air conditioner from my 560 Ah LiFePO4 battery bank (240 amp combined BMS rating). It ran it with no issues.
I had that same generator (Onan QG 5500) in the RV and I never once overloaded the generator. It ran the air conditioner just fine through the Multiplus.
While the inverter ran the air conditioner without any complaint, I did add a soft start module to the air conditioner to reduce the startup surge. This is one option for you and probably something that should be done no matter what. I use the Micro-Air EasyStart but there are plenty of other soft start devices available.
Given that we have the same inverters, same generators and similar air conditioners, I think there is something wrong with your setup. When the generator is running, the priority in the Multiplus is the AC loads. It will reduce the battery charging when the AC loads ramp up.
Do you have Power Assist turned on?
What is the max AC current input value set to? This value will limit how many amps the Multiplus will draw from AC-in-1. If it’s set too low then it’s not making full use of the power available from the generator. However, since it works fine on shore power, this setting probably isn’t the issue.
How long is the cable run from the generator to the Multiplus, and what size is the cable? If the cable is undersized you may be dropping the voltage which could have downstream affects.
Has the generator been serviced and tested lately? How many hours are on the generator?
Post a picture of how your battery bank is wired up. Connecting multiple batteries in an optimal way isn’t simple. Check out the Victron Wiring Unlimited paper for guidelines on how to connect multiple batteries.
Thanks all, I cranked the input limit up to 50. ( I had it set at 30)Working fine now. I will get the soft start, I have used them before.
Thanks again,
Tony
Did you update your multi to v552 yet ? Victron solved some problems here, especiallly regarding waveform and power-factor.