Converter Not Working With Generator

Mattjackson · 07-31-2021, 10:31 PM

Hi,

I’m fairly new to trailers but recently purchased a 2020 Grey Wolf Limited.
We are planning to do a lot of dry camping, normally for just a weekend but sometimes 7-10days. The trailer had an interstate lead acid battery that was not going to do the job. I purchased 4x 3.2v LifePo4 with a BMS and they are really good, couldn’t be happier with them.

They will last the week if the kids don’t leave things on etc.. When connected to shore power, just a 15A cord with the little adaptor to convert to the trailers 30A 120v cord, the batteries will charge, the BMS shows it charging, when towing it also charges. Now when I connect the trailer to a generator it does not. It’s a brand new 3600w generator with a 30A receptacle on it, it has a digital screen showing me that it puts out 121v at 60hz and yet it won’t charge them. It’s an inverter generator so it shouldn’t be putting out noisy AC. All of the breakers are good, the fuses are good, every 120v outlet works, the microwave and the fireplace all work including the aircon. It must be the converter not liking a generator, but what’s the fix here?
Is there a different converter I put in it instead, do I just get a regular battery charger and hook it straight to the batteries and run that on the generator? It’s very odd.
Any input would be greatly appreciated!

rsdata · 07-31-2021, 10:37 PM

lookup a neutral bond plug

lots of threads on this

easy to make yourself and might solve your issue

Mattjackson · 07-31-2021, 11:46 PM

Okay, I will give this a go and will let you know how it works. I will go Home Depot in the morning and get the bits to do it. I just watched a YouTube video on it. Looks extremely easy, hopefully it works.

CHICKDOE · 08-01-2021, 09:13 AM

i doubt that it is the neutral plug as all of the other 120 devices work. the neutral plug is to allow an ems to pass power then the generator neutral and ground are not bonded. since all the other 120 devices are working on the generator this is not the problem.

it is hard to believe that the converter can tell the difference between shore power and generator power. i know you said that the batteries charge when connected to just a 15 amp shore power cord. was that a prior experience or is that right now? i would like to know that the converter works right now on shore power but not on generator power. that is hard to believe.

the issue does appear to be centered on the converter. one thing that i would check is if the reverse polarity fuses on the converter might have blown. i'm wondering if the increased amperage that the lithium batteries can take might have caused these fuses to blow. you did not say you upgraded the converter to a lithium model when you out the new batteries in. but if they were blown the converter would not charge the batteries using the 15 amp shore power cord either.

let us know what you find.

Mattjackson · 08-01-2021, 09:37 AM

Hi.
So the place that supplied me with the batteries said that the factory charger will be fine. And yes it does charge them. I can literally have a cord coming from the generator and one directly from the house and if I plug in to the house the BMS shows it’s charging, if I unplug that one and plug in the generator, it will not charge. I will give the bonded neutral plug a try as if you think about, it’s one of the only major differences between the two power sources. Just waiting for depot to open.

rsdata · 08-01-2021, 09:41 AM

Quote:

the neutral plug is to allow an ems to pass power then the generator neutral and ground are not bonded. since all the other 120 devices are working on the generator this is not the problem.

I missed the part where all the other 120 VAC plugs works... I read he said none of them worked... my bad for leading astray...
but something is wrong here...

**wmtire** · 08-01-2021, 09:42 AM

I am curious as I do not have any experience with these Battery Management Systems (BMS) for these type batteries. The G-N bonding plug is required for generators AND the use of an Electrical Management System (EMS) that sense an open neutral or ground in order to pass thru power.

I wonder if the BMS does something similar, but would have to see how it wired. If it's wired downstream of the converter, I wouldn't think it would matter. I am curious and will be following.

TitanMike · 08-01-2021, 10:23 AM

Quote:

Originally Posted by wmtire

I am curious as I do not have any experience with these Battery Management Systems (BMS) for these type batteries. The G-N bonding plug is required for generators AND the use of an Electrical Management System (EMS) that sense an open neutral or ground in order to pass thru power.

I wonder if the BMS does something similar, but would have to see how it wired. If it's wired downstream of the converter, I wouldn't think it would matter. I am curious and will be following.

I doubt the BMS would even 'see' anything on the 120 volt side of the Converter as it's purpose is to merely protect the cells in the LiFePo4 battery and make sure the cells are balanced.

One thing that makes me wonder is from the original post I gather the battery is a DIY LiFePo4 unit assembled from components. As a rule the BMS used for these batteries don't "indicate" anything unless equipped with a Bluetooth board. A "BMV" is often the device indicating charge like one of the usual shunt type monitors.

If a Neutral Bonding Plug solves the problem it would be a surprise but if it does-----------

I know that my LiFePo4 batteries charge just fine from my Inverter generator or Shore Power with no Neutral Bonding Plug and even a "Home Brew" battery should as well. Time perhaps to drag out the Multimeter and do some testing from generator to Converter.

Mattjackson · 08-01-2021, 12:10 PM

Hi.
So the bonded plug has no change… We are just about to head out of town for a week so I will have to investigate this when I get back home… Might have to look in to a new converter.

CHICKDOE · 08-01-2021, 12:32 PM

before i did anything else i would use a meter to test the voltages at the battery terminals when connected to shore power and generator power. i still find it odd that the converter seems to run on shore power and not on generator power when you say every other 120 volt device does.

dave1650 · 08-01-2021, 06:07 PM

Quote:

Originally Posted by Mattjackson

Hi,

I’m fairly new to trailers but recently purchased a 2020 Grey Wolf Limited.
We are planning to do a lot of dry camping, normally for just a weekend but sometimes 7-10days. The trailer had an interstate lead acid battery that was not going to do the job. I purchased 4x 3.2v LifePo4 with a BMS and they are really good, couldn’t be happier with them.

They will last the week if the kids don’t leave things on etc.. When connected to shore power, just a 15A cord with the little adaptor to convert to the trailers 30A 120v cord, the batteries will charge, the BMS shows it charging, when towing it also charges. Now when I connect the trailer to a generator it does not. It’s a brand new 3600w generator with a 30A receptacle on it, it has a digital screen showing me that it puts out 121v at 60hz and yet it won’t charge them. It’s an inverter generator so it shouldn’t be putting out noisy AC. All of the breakers are good, the fuses are good, every 120v outlet works, the microwave and the fireplace all work including the aircon. It must be the converter not liking a generator, but what’s the fix here?
Is there a different converter I put in it instead, do I just get a regular battery charger and hook it straight to the batteries and run that on the generator? It’s very odd.
Any input would be greatly appreciated!

I would try disconnecting the converter until the generator is running normal then turning it on. If the generator is bogging down when you plug in the converter may be going into a shutdown because of the low voltage and current demand from the batteries. Your converter may be at nearly max to charge the batteries and the momentary lower voltage from the generator may be enough to shut it down. Just a thought simply because nothing else makes any sense. Turning off other 12 VDC loads may also be helpful. Good luck.

Mattjackson · 08-05-2021, 11:24 AM

Hi,

An update…..

So once again I plugged the trailer in to the generator and the BMS shows it’s still not charging. I got my hands a digital meter and did the following.
When connected to the generator the converter is receiving 123v which confirms what the generators display is saying it’s giving out. I turned the BMS off which isolates the batteries from the trailers panel, The converter puts out a little over 13v. After turning the breaker on and off to the converter a few times, the converters fan started up and then when I turned the BMS back on, shows it’s charging. The BMS shows it’s receiving 11.87A back. So definitely points to the converter, likely faulty or just doesn’t like the new batteries (only when on generator though, as this never happens on shore power). Interestingly on another occasion, the BMS only showed that it was receiving 1.87v back and it barely charged. On shore power it receives 12A plus every single time, when connected to the truck it gets back around 3-4A.

Can anyone suggest a better converter charger. It’s a 30A converter charger 12v 55A that currently sits in the bottom of the panel. I don’t mind if I have to move it if a better one is not able to be a direct replacement.

CHICKDOE · 08-05-2021, 11:38 AM

i can't explain what is going on.

but if you are going to replace the converter look into replacing with a converter designed for lithium batteries. the 13 volts you are seeing will not fully charge the lithium batteries. you need about 14.6 bolts to fully charge lithium.

**ependydad** · 08-05-2021, 11:39 AM

If it were me, I would reach out to the battery maker and find out which converter that they recommend.

I'd then run a 20am line + wire in a new outlet in the same compartment as the batteries so that you have as short of a connection as possible between the charger and batteries.

dave1650 · 08-05-2021, 10:06 PM

Quote:

Originally Posted by Mattjackson

Hi,

An update…..

So once again I plugged the trailer in to the generator and the BMS shows it’s still not charging. I got my hands a digital meter and did the following.
When connected to the generator the converter is receiving 123v which confirms what the generators display is saying it’s giving out. I turned the BMS off which isolates the batteries from the trailers panel, The converter puts out a little over 13v. After turning the breaker on and off to the converter a few times, the converters fan started up and then when I turned the BMS back on, shows it’s charging. The BMS shows it’s receiving 11.87A back. So definitely points to the converter, likely faulty or just doesn’t like the new batteries (only when on generator though, as this never happens on shore power). Interestingly on another occasion, the BMS only showed that it was receiving 1.87v back and it barely charged. On shore power it receives 12A plus every single time, when connected to the truck it gets back around 3-4A.

Can anyone suggest a better converter charger. It’s a 30A converter charger 12v 55A that currently sits in the bottom of the panel. I don’t mind if I have to move it if a better one is not able to be a direct replacement.

Does your generator surge when you turn the converter or BMS off and then on? If you have the 280AH batteries what is the current draw to charge them? It may simply shut the converter down due to over current because of the sudden surge. My understanding is your batteries will charge at a much faster rate then lead acid which must take more current. A converter made to charge Lithium batteries may resolve the problem and it may be better for the batteries. WFO may have a direct replacement. There may be better choices but I am not familiar with other brands.

AlanMoor · 08-06-2021, 10:09 AM

FYI I have the same battery (LifePO 280AH) and my stock 55A converter doesn't appear to charge it, or at best it is anemic (<10A). I suspect this is because the converter "sees" the higher voltage from the battery, and since it thinks it is FLA, it thinks it is already charged so it doesn't charge any more (or sends a minimal charge). I've actually seen the BMS reporting that it is discharging when the converter is plugged in. Right now I have an 18A DC-DC charger for the truck ($100) and 200W of solar (the controller supports lithium), and a 10A stand-alone charger.

I don't know why you'd see a difference on a generator though... I built a similar battery for my brother in law and his BMS shows it charges at 55A with a 55A WFCO lithium compatible charger when he runs his 9K generator. We didn't try it with the converter configured for FLA.

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