AC Unit seems to work on shore power & batteries, but not on generator

[StogieMan]

Originally Posted by Hawk-ination

I just fixed having the wrong wire going through my mini-PMS. While testing, my shore power worked fine, but I’m still not getting the generator to charge my bank of Battle Borns. Any ideas? I’m quite clueless as to why they wouldn’t charge.

Hi Hawk.

I’m not sure how your setup is wired as I know that you did a lithium upgrade so I’ll just take a crack at the low hanging fruit.

I’m going to assume that the generator is working and getting power to start it. If not make sure that there is power to start it going to it. There should be a 2Ga cable going to your positive buss bar from the generator.

Check the breaker at the generator. My generator will trip the fuse and still continue to run without providing any power. So, it may seem like it’s on and running but it may be tripped. I can check mine through the GX monitor and know if it tripped as I would not see any power coming from it.

Next open up the Airstream provided Automatic Transfer Switch. There are three connections in there. One input for the shore power connection, one for the generator connection and an out to either go to your Victron Multiplus or or AC distribution panel depending on how it is wired up. Check the generator connections at the ATS with a meter to make sure that you have incoming power from the generator and make sure that there are no loose connections there. Although the ATS’s are usually pretty durable, I did have one go bad on me on my last Sprinter B. If it is the case that the ATS is bad, please don’t buy a new as I have two that I have taking up space and will gladly ship it to you for free.

Your batteries should be getting charged up from the power coming in from ATS to the inverter whenever tied to shore power or when running the generator. The 6Ga cable going to the positive bar is not for charging but just to give the genny power to start it.

Lastly check your fuses going to your positive side of the batteries and any going to any of the buss bars.

Hope this helps. If you can share some pics of your setup that can be helpful too.

[Hawk-ination]

Good point on all accounts. Think I’ll start at the fuse on the generator, then follow the sequence. I guess I did’t realize it would run but not charge if there’s a problem there.

Yes, it does run but certainly not charging. I do not have the Cerbo GX yet. Maybe Santa should bring one this year from the sounds of it.

I did not see any suggestions while setting up Victron Connect to change the charging settings but have now finally found the Victron chat. There’s a couple suggestions for smaller generators to try. Has anyone changed their charger settings either? Just curious on that point as I will follow troubleshooting first today.

Thanks for helping out with suggestions. Finally getting the time to fully troubleshoot my system.

[StogieMan]

You usually don’t have to mess with the Victron Multiplus settings if you purchase the batteries and Multiplus from the same vendor as they will program it for you.

The one setting that usually messes with the generator on the Multiplus is the UPS function and that should be turned off.

Below are two videos that should help you out. Also contact Battle Born regarding the settings as they should help you out as I’ve always heard that their customer service is great.

https://m.youtube.com/watch?v=pVVd46rU-5U

https://m.youtube.com/watch?v=n3V2dZ24VlQ

[Rocinante]

At one point we had the exact scenario that StogieMan suggests: the breaker on our generator popped because we drew too many amps. The generator ran just fine, but produced no power. The breaker is actually on the generator, under the van, behind an access panel. I found that panel from the rear side of the generator, opened it, and reset the breaker. No audible change in generator performance, but once I did that it produced power again. Sorry I didn't suggest this sooner!

Originally Posted by Hawk-ination

Good point on all accounts. Think I’ll start at the fuse on the generator, then follow the sequence. I guess I did’t realize it would run but not charge if there’s a problem there.

Yes, it does run but certainly not charging. I do not have the Cerbo GX yet. Maybe Santa should bring one this year from the sounds of it.

I did not see any suggestions while setting up Victron Connect to change the charging settings but have now finally found the Victron chat. There’s a couple suggestions for smaller generators to try. Has anyone changed their charger settings either? Just curious on that point as I will follow troubleshooting first today.

Thanks for helping out with suggestions. Finally getting the time to fully troubleshoot my system.

[StogieMan]

Originally Posted by Rocinante

The breaker is actually on the generator, under the van, behind an access panel. I found that panel from the rear side of the generator, opened it, and reset the breaker. No audible change in generator performance, but once I did that it produced power again. Sorry I didn't suggest this sooner!

Yup, on is in the up position.

[Rocinante]

Went out to the van today, post hurricane Nicole, to work on a few things. While there, I did some empirical experiments with the generator, the Victron Multiplus, and the air conditioner.

Scenario one: Turn on the inverter, and then start the generator. At first I was disappointed, because the EMS lit up in generator mode. So, despite having the inverter running, the EMS was clearly aware of the generator. I had been hoping otherwise. Despite this, I left the inverter on. As usual, power started hitting the batteries fairly quickly, before the EMS was technically willing to let the van consume power from the generator - so, as expected, I can charge the van's batteries from the genny while the inverter is running. Once the EMS was happy with the incoming generator power and ready to run the air conditioner, I did what I usually do: I turned the incoming power dial on the Victron digital controller to zero. Then I started the air conditioner. It started right up, no issues, and I could see the unit drawing 13 amps on the EMS display. However, when I looked at the BMV712 Smart display, I noticed that all the power going into the air conditioner seemed to be coming from the batteries. Ok, based on that I started turning up the incoming power dial on the Victron digital controller, eventually reaching 20 amps...without popping the generator's breaker. Also, once I did that I had net positive amps going into the batteries instead of coming out. So, huge discovery for me. A key secret for running our van's air conditioner on generator in our configuration is to turn on the inverter and spin the Victron digital control dial up to 20. That way, the inverter can help out if needed, and everything works fine.

Scenario two: I wanted to test my pet theory that there was a voltage drop with the genny while trying to run the air conditioner with the Victron inverter shut off and the Victron digital control dial set to zero. Nope, no voltage drop when it tried to start the AC unit. However, unlike a few days ago, this time the air conditioner successfully started and kept right on running. What could have caused this change of heart in my AC unit? I have no idea...sticky compressor freed up by running it a bit first? Lower temps made it easier to start the compressor and keep it going? I have no idea.

Apparently there's nothing wrong with the generator, and nothing consistently wrong with the AC unit, so we'll just keep using them both as is, until one or the other dies.

Anyway, from now on we'll just flip on the inverter, start the generator, spin the Victron digital control dial to 20, and then start the AC unit. At least that way we can count on the Multiplus to do a good job managing power distribution and preventing the generator's breaker from popping.

[Rocinante]

BTW, with 400 Ah in the battery bank we can of course run the air conditioner on batteries alone for a while, but that’s something we usually reserve for short stops on hot travel days because after a while hitting the batteries and inverter that hard generates heat inside the van, which is kinda the opposite of our goal. [emoji57]

[StogieMan]

Rocinante, I’m glad that you got it all worked out.

Just an FYI - make sure that you don’t have the same issue with other loads like the microwave and coffee maker with the digital controller not set to 20A’s when the generator is on. On ours, the light on the microwave may be on but when we turn it on to put a load on, it will trip after a few minutes. It’s the same with our coffee maker. At least with our setup this is what goes on when the generator is on and the digital controller not set to 20A incoming and I’m going to assume that it will probably be the same for you.

The Multiplus does get hot when charging and not so bad when in use. I usually run the generator when driving to charge the batteries while the AC is in use or not.

This morning I had the generator on to charge our batteries and along with the new Victron BuckBoost was getting 120A of charging into the batteries which is great!

Bottom line, don’t be afraid to run the genny while driving as it will get your 400Ah’s of lithium charged up pretty quick.

[Rocinante]

Yes indeed, good point on the genny while driving. Also, since we have a Victron Cyrix isolator / combiner in the van, our alternator provides plenty of amperage into the batteries and helps keep them charged while driving. I wouldn't try to run the AC off that because the air conditioner's draw is so big, but we could certainly run the genny if we need that extra cooling.

I don't like to run the genny much because it's just so darn loud, but it's good to know I can when I need to and that in exchange for that awful racket it will actually let me cool the van. Also, replacing that noisy beast of a genny with a newer and quieter inverter-based Cummins generator is on our list, but I'm kinda waiting until this one either dies or I finally lose my patience with it. Ha!

[Hawk-ination]

It got too cold at the moment to test everything. Will try to get in the garage and perform the remainder of the tests over the weekend.

Is anyone willing and able to share their Victron Connect settings with me please? I would like to check to see if I have the settings correct to run with the Onan.

I did go out and check along with move the circuit breaker back and forth, then back to the up position. Thanks for sharing that little tidbit cause I didn’t want to be out there any longer than a couple of minutes to figure that out! As much as I wanted it to be, it doesn’t seem like it was the problem, but thanks so much for the advice to check it.

I’ll post more information if anyone is curious on the situation, but trying to do a few tests and trials before we have to get it put away before the snow flies next week. Thanks to everyone who’s made suggestions so far.

[Hawk-ination]

Let me correct my question, I am looking to verify the settings in VEConnect if anyone is able to provide any data on their settings, especially the Grid, Charging, and Inverter tabs and has an Onan 2.5 generator on their Interstate.

Thanks.

[Hawk-ination]

Sorry everyone, not trying to beat a dead horse here.

Anyone, if having programmed their Victron, remember if they checked or unchecked the UPS function in the “Grid” connection?

[Rocinante]

I recently saw a video that said to disable the UPS function so it doesn't get in the way when using a generator, but of course now I can't find it. If I can locate it, I'll post. Sorry I'm not able to be more immediately helpful.

(Edit)
Found the video here (skip to roughly 2:50 to see him speak briefly about that setting in the context of generators. That said, I don't know how our unit is configured in this regard, because I just let the installer deal with it.):

https://www.youtube.com/watch?v=A6XsygejrVA

Also, found the manual here: https://www.victronenergy.com/invert...a-3kva#manuals. I scrolled down to the Service Manual for the Multiplus, which linked to here: https://www.victronenergy.com/upload...4xx)-EN-ES.pdf

Here's the relevant paragraph regarding the UPS feature. Doesn't seem like a huge deal either way, more useful with a crappy and/or under-powered genset:

UPS feature
If this setting is ‘on’ and AC on the input fails, the MultiPlus switches to inverter operation practically without interruption. The MultiPlus can therefore be used as an Uninterruptible Power Supply (UPS) for sensitive equipment such as computers or communication systems.
The output voltage of some small generator sets is too unstable and distorted for using this setting – the MultiPlus would continually switch to inverter operation. For this reason, the setting can be turned off. The MultiPlus will then respond less quickly to AC input voltage deviations. The switchover time to inverter operation is consequently slightly longer, but most equipment (most computers, clocks or household equipment) is not adversely impacted.
Recommendation: Turn the UPS feature off if the MultiPlus fails to synchronise, or continually switches back to inverter operation.

[StogieMan]

Originally Posted by Hawk-ination

Sorry everyone, not trying to beat a dead horse here.

Anyone, if having programmed their Victron, remember if they checked or unchecked the UPS function in the “Grid” connection?

Hawk,

If I get a chance tomorrow, I'll open it up and attach the MK3-USB module to it and to the laptop. I'll take some pics of the settings. The only one that I do remember is the UPS function that I turned off.

This is the only one that I know how to access the settings is by attaching the MK3-USB.

[StogieMan]

I meant to say in the last sentence that this is only way I know how to access the Victron Multiplus settings as I don’t have the Bluetooth dongle attached to the Victron Multiplus. I have one but did not attach it to it as it only has two RJ45 ports on the Multiilus and we have the digital controller and the Cerbo attached to it.

I bring this is up as I just thought of something. Do you have a Bluetooth dongle for the Victron Multiplus? If not, how are you controlling the power inputs on it?

If you do have the bluetooth dongle and can access the Victron Multiplus from the Victron app, make sure that you have it dialed down to 20A when the generator is on for the input.

Again, I’ll take a look at the settings later today.

https://www.amazon.com/dp/B07FCV43LQ..._1668515379283


Take a look around the 26:20 mark as he gets into the Bluetooth dongle install and settings.

https://m.youtube.com/watch?v=01F4QDVJUq0

[Rocinante]

I have a bluetooth dongle on the BMV712Smart (which monitors the flow of DC power) but not on the Multiplus. The Victron Digital controller plugs into a VE Bus terminal on the Multiplus, so that's how we control it remotely, though that doesn't really tell us anything about the flow of AC power. The dongle / bluetooth connection shown in the video above is pretty cool because it would be nice to see that information on the Victron device instead of relying on the Airstream-installed EMS, which clearly doesn't tell the whole story.

[Sailfast]

Originally Posted by Rocinante

I have a bluetooth dongle on the BMV712Smart (which monitors the flow of DC power) but not on the Multiplus. The Victron Digital controller plugs into a VE Bus terminal on the Multiplus, so that's how we control it remotely, though that doesn't really tell us anything about the flow of AC power. The dongle / bluetooth connection shown in the video above is pretty cool because it would be nice to see that information on the Victron device instead of relying on the Airstream-installed EMS, which clearly doesn't tell the whole story.

Rocinate, it looks like you may have found a workaround for operating AC with gen set. You say you have an EasyStart(?). Well there is the issue, the EasyStart does not like what it sees coming from the generator.

The EasyStart can be adjusted to "re-learn" incoming voltage/current. Send them an email and they will work you through.

here is an excerpt



Micro-Air Technical Support <help@microair.net>
Aug 8, 2022, 3:14 PM

to me

Hello Felix,

I suspect it had a marginal value that it did not like when the generator was used. Glad to help.

Best regards,

Roger


From: xxxx
Sent: Monday, August 8, 2022 3:05 PM
To: Micro-Air Technical Support <help@microair.net>
Subject: Re: EasyStart Soft Starter - From Felix Felix

Interesting ......., Voltage at relais ingoing for ac compressor 119.6V, once compressor starts voltage jumps briefly to 120.5.

Of course, the compressor shut off right away. Next, we did the relearn process according to instructions, and it now works. Has been running for 20 minutes and it still works. So we can conclude it works.

Tank you for the assistance.

Felix K

On Mon, Aug 8, 2022 at 9:15 AM Micro-Air Technical Support <help@microair.net> wrote:
Hello Felix,

Ok, that confirms that it is indicating a stall. Can you measure the voltage at the air conditioner input during the start? I want to see if the generator is dropping voltage for an excessive time for some reason.

If the voltage remains constant, please try a relearn using THIS process while on generator. If it still stalls on the first learning start, please let me know.


Thanks,
Roger

[Rocinante]

Cool idea, thanks! Sadly, causing the EasyStart to re-learn seems to require that I get on the roof, open up the AC shroud and the EasyStart case, flip a dip switch or two, etc. to put it back into factory condition, put it all back together, and have it re-learn while on generator instead of shore power or inverter. I'm not willing to get up on the roof to do all that stuff, so I'll have to either keep getting it to work as I have done so far, or maybe hire a mobile RV mechanic to do that rooftop work for us. It wouldn't take long, and it's less unpleasant than many tasks mobile RV mechanics do, so if we need it, finding someone to pay for an hour of labor plus travel time shouldn't be too hard. Also, we may be passing through Quartzsite this winter, and there are plenty of RV mechanics there during the season, so that would also be pretty easy.

https://www.micro-air.com/kb-easysta...ft_Starter.cfm

[Sailfast]

Originally Posted by Rocinante

Cool idea, thanks! Sadly, causing the EasyStart to re-learn seems to require that I get on the roof, open up the AC shroud and the EasyStart case, flip a dip switch or two, etc. to put it back into factory condition, put it all back together, and have it re-learn while on generator instead of shore power or inverter. I'm not willing to get up on the roof to do all that stuff, so I'll have to either keep getting it to work as I have done so far, or maybe hire a mobile RV mechanic to do that rooftop work for us. It wouldn't take long, and it's less unpleasant than many tasks mobile RV mechanics do, so if we need it, finding someone to pay for an hour of labor plus travel time shouldn't be too hard. Also, we may be passing through Quartzsite this winter, and there are plenty of RV mechanics there during the season, so that would also be pretty easy.

https://www.micro-air.com/kb-easysta...ft_Starter.cfm

You got it, that's exactly how its done. If you can find someone who has worked on these things before, great. Good luck!

[richard5933]

If your easy start is a newer one with Bluetooth you can initiate a relearn from your smartphone.

When the tech is out to help, it might be a good idea to upgrade to a new one with Bluetooth. It might be cheaper in the end if you need to pay someone to get on the roof every time it needs to relearn.