Batteries turn themselves off during charge

[watkins]

2023 Fuzion... with Solar 400 package and 200AH Dragonfly lithium.

If the batteries run themselves down to dead and I fire up generator or plug into shore power... I'll watch the charge amps on the shunt start to jump up and then I can hear an audible click (which I traced to the batteries themselves) and the amps drop to 0... this will repeat itself over and over until the charge controller is putting out less than 60 amps, at that point the batteries wont shut themselves off and will keep charging.

I'm assuming the BMS for the batteries doesnt like anything over 60amps.. is there a way to set the converter/charger to not exceed this? I'd imagine it cant be good for the batteries to be clicking on and off all the time like that.

[SargeW]

Your system probably has a Victron Battery Charge Controller and a Victron Shunt. This You Tube Video will explain how to go about setting up your Battery Charge Controller. You Tube Videos are your friend, and will take a lot of the mystery out of using your system.

https://www.youtube.com/watch?v=aPB4NiOAZIo&t=327s

[watkins]

Victron is the solar charger, and I’ve got that tuned to my needs.

The standard converter/charger is a WFCO on my rig.

[SargeW]

How big is the converter? I have the same solar/battery set up and my WFCO converter is a 9855, meaning that the max output is 55 amp. WFCO also has a 65 and a 75 amp model, so if your converter is pushing more than that, that could trip off the over voltage setting in the BM of the batteries.

Can you access your converter to see what model is installed?

[watkins]

Mine has a 90amp converter. PD4590TB

Seems excessive considering the batteries can’t take it.

[JRTJH]

Originally Posted by watkins

Victron is the solar charger, and I’ve got that tuned to my needs.

The standard converter/charger is a WFCO on my rig.

Originally Posted by watkins

Mine has a 90amp converter. PD4590TB

Seems excessive considering the batteries can’t take it.

So, are you saying that you've changed out the converter/charger in your trailer from the OEM WFCO to a PD 90 amp converter/charger ???

[watkins]

Originally Posted by JRTJH

So, are you saying that you've changed out the converter/charger in your trailer from the OEM WFCO to a PD 90 amp converter/charger ???

No, I had pulled up specs online for my rig and said WFCO… went out this morning and pulled it out and the OEM on my rig was a PD 90amp.

So I had assumed the online specs were correct. You know what they say when you assume right?

[xrated]

Originally Posted by watkins

2023 Fuzion... with Solar 400 package and 200AH Dragonfly lithium.

If the batteries run themselves down to dead and I fire up generator or plug into shore power... I'll watch the charge amps on the shunt start to jump up and then I can hear an audible click (which I traced to the batteries themselves) and the amps drop to 0... this will repeat itself over and over until the charge controller is putting out less than 60 amps, at that point the batteries wont shut themselves off and will keep charging.

I'm assuming the BMS for the batteries doesnt like anything over 60amps.. is there a way to set the converter/charger to not exceed this? I'd imagine it cant be good for the batteries to be clicking on and off all the time like that.

There should be spec sheets available for that battery...somewhere. One of the data points is max charge current and max discharge current....which would be something pretty valuable to know before buying a particular battery or changing out a Charger/Converter if you did that. As an example, the battery that I built is 302AH and the BMS that I used for it is a 200A BMS. The data for the cells that I used to build the battery states the the normal charge current can be up to 0.5C at 25 degrees Centigrage, which means on the 302AH battery it should be able to handle up to around 150 amps for charging it. But, it is able to take up to 250A of charge or discharge....the cells themselves. I've limited my build via the BMS because I have absolutely nothing in my trailer that even comes close to needing that much current and I certainly don't have any means of charging even close to that current, so I basically just limited it by using a 200A BMS

So where along the line, you ended up with more charging current available than what the battery (BMS) is capable of allowing.

[xrated]

Originally Posted by watkins

No, I had pulled up specs online for my rig and said WFCO… went out this morning and pulled it out and the OEM on my rig was a PD 90amp.

So I had assumed the online specs were correct. You know what they say when you assume right?

Did the battery that you have come with the rig, or did you replace the original battery with the 200AH Dragonfly battery?

One of the only options I see for this is to either get a battery that can handle the amount of current the converter is throwing at it, when in bulk mode and charging....or the lesser option dollar wise would be to buy the 60A converter that fits in that panel, and then try to sell the 90 to someone to recuperate some of your cost.

[SargeW]

Sounds a lot like overkill for sure. Since that converter will push 90 amps, I wonder if the wiring they installed is capable of handling that much amperage. The 55 amp converter in my rig handles that amperage easily, as mine will usually push about 42 - 45 amps as tested by my DC volt meter. They would have had to about double the size wiring for a converter that big.

[watkins]

Originally Posted by xrated

Did the battery that you have come with the rig, or did you replace the original battery with the 200AH Dragonfly battery?

One of the only options I see for this is to either get a battery that can handle the amount of current the converter is throwing at it, when in bulk mode and charging....or the lesser option dollar wise would be to buy the 60A converter that fits in that panel, and then try to sell the 90 to someone to recuperate some of your cost.

Original converter and original dragonfly batteries. Strange right.

[JRTJH]

Have you considered putting a DC amp gauge on the battery cable input to the battery to see if the actual input to the battery exceeds the BMS maximum capability??? Could be that the trailer system is working correctly (providing say, 50 or 55 amps) and the BMS is "tripping below the design threshold"...

Seems to me, there should be a "built in BMS battery charge limiter" (not a charge interruptor to the battery) circuit that reduces the charge to a safe level rather than shuts down all charging because the available power exceeds the BMS capacity. Now, that's my opinion and that may not be the way your battery BMS works, Dragonfly can verify that for you.

It may be cheaper for you to install a "charge limiter/regulator device" on the battery charge input rather than replace either the PD converter/charger or the battery..... But, knowing what the amperage going into the battery with a DC amp gauge would identify whether it's the converter/charger providing too much power for the BMS or if the battery BMS is shutting down at, say 45 amps or 50 amps input.... I'd think you need to know accurately what is going into the battery before blaming the converter and/or the battery BMS.....

Something to consider: Should you just replace the converter/charger with one that has a lower maximum output, in the winter, running your furnace, heat pads on the tanks and other DC powered devices, you may create a situation where the converter/charger can't adequately keep the battery charged plus power all the additional requirements. There's usually a reason why Keystone would install a more expensive, larger output converter in the trailer. Without knowing all their "design considerations", should you just downgrade your converter, you may "cure one issue and create other issues"...


I would guess that your trailer is still in warranty ??? If so, even with the delays in getting an appointment for service or repairs, I would get Keystone involved before buying expensive parts to throw at a problem, expecially if those parts may lead to problems when the trailer is out of warranty....

[xrated]

Originally Posted by watkins

Original converter and original dragonfly batteries. Strange right.

Well, I would say that someone at the factory screwed up and didn't their their spec sheet check out to see if it would work with the 90A converter and the battery that they used. The only other thing is.......is it possible that the selling dealer chose the battery, or did the battery actually come from the Keystone factory. Most trailers get the battery once they arrive at the dealership and are getting prepped for sale.......so I don't know where the fault lies, but someone besides you should be making this whole thing right.

Something else I would do, before anything, is to find the spec sheet for YOUR battery and see what the actual numbers are for the max. charge current into it....just to make sure whether or not the 60A is the cutoff. My point is this....what if the BMS is defective and it actually is suppose to be allowing up to say 100 amps. If that were the case, then it has now become a defective battery, because of the BMS, instead of a screw up by mis-matching the battery and the charger.

[watkins]

Originally Posted by xrated

Well, I would say that someone at the factory screwed up and didn't their their spec sheet check out to see if it would work with the 90A converter and the battery that they used. The only other thing is.......is it possible that the selling dealer chose the battery, or did the battery actually come from the Keystone factory. Most trailers get the battery once they arrive at the dealership and are getting prepped for sale.......so I don't know where the fault lies, but someone besides you should be making this whole thing right.

The dealer may not have installed them but they did spec for them. If you look up the 400i solar package it says "optional 100AH dragonfly lithium batteries can be added by your dealer".

At this point tempted to sell the 2 x dragonfly batteries (just dealer branded battle borns) and get a 270ah battle born GC3 which can take over 100 charging amps. I was planning on adding a 3rd 100ah lithium as 200 just wasnt enough.

[xrated]

Originally Posted by watkins

The dealer may not have installed them but they did spec for them. If you look up the 400i solar package it says "optional 100AH dragonfly lithium batteries can be added by your dealer".

At this point tempted to sell the 2 x dragonfly batteries (just dealer branded battle borns) and get a 270ah battle born GC3 which can take over 100 charging amps. I was planning on adding a 3rd 100ah lithium as 200 just wasnt enough.

Go back and reread my previous post.........I edited it and added some more info for you to read.

PS......one other question....is the battery and actual 200AH or is there two 100AH batteries hooked in parallel? The reason that I ask is that I could see where a 100AH battery might have a 50A input limit for charging, but I would think that at 200AH battery would likely be in the 100A input range for charging. It kind of goes back to my previous post about the specs for charge current on these LFP batteries, manyt times are 1/2 of the AH rating....that's where you probably saw me referring to the 0.5C number earlier.

[watkins]

Originally Posted by xrated

Go back and reread my previous post.........I edited it and added some more info for you to read.

I did. 50amp max amperage on my 100AH lithium. S

[SargeW]

My 400i set up came from Keystone with the batteries already installed. My dealer in Nevada had no Lithium batteries on hand, and usually didn't stock them. Then again, I did purchase a unit from Keystone that was on their lot after being built. The dealer had a few of my model in stock, just not optioned the way we wanted it.

[xrated]

Originally Posted by watkins

I did. 50amp max amperage on my 100AH lithium. S

So if I'm understanding you correctly, you have two 100A batteries in parallel....I originally though the battery was a single 200AH battery, not two 100s. Theoretically, the output from the Converter/Charger (90 amps max), should be dividing that current up equally to the two batteries (a parallel circuit path) and should result in 45 amps being fed to each battery....given that everything is equal. And that 45 amps should be within the range of current for an individual battery's BMS

[watkins]

Originally Posted by xrated

So if I'm understanding you correctly, you have two 100A batteries in parallel....I originally though the battery was a single 200AH battery, not two 100s. Theoretically, the output from the Converter/Charger (90 amps max), should be dividing that current up equally to the two batteries (a parallel circuit path) and should result in 45 amps being fed to each battery....given that everything is equal. And that 45 amps should be within the range of current for an individual battery's BMS

Going to have to do some more digging on this one.... let me drain the battery again and do some more testing. What you said makes perfect sense but what is happening is not.

[xrated]

Originally Posted by watkins

Going to have to do some more digging on this one.... let me drain the battery again and do some more testing. What you said makes perfect sense but what is happening is not.

There are some caveats to this, and I'll try to explain. In a perfectly equal parallel circuit, the total amount of current flow is evenly divided over however many parallel paths there are....in this case, two. However, as you probably realize, the two batteries may actually have a bit of difference as far as the resistance to the current flow. Differences can arise from internal battery resistance, a connection that is not, shall we say equal to the others, in the form of a bit of higher resistance. There could also be a crimp connection that is a bit higher in resistance, as well as some of the finer points of possibly a battery being balanced and the other not as much. LFP batteries really need to be really close as far as being top balanced. The factor came into play as I was building my battery from four 302AH individual cells, and I spent some time top balancing them when the build was done. Of course on a complete battery like yours, you cannot balance the individual cells inside, and the best you can do is to try and make sure the each battery is balanced with each other. When/if they get out of balance a bit, that can cause one to not charge at the same rate as the other, and if your BMS is looking for anything over 50A as a cutoff for current when charging, and one is pulling slightly over that, it could be the factor for the BMS taking it offline for charging. I certainly wouldn't think that two batteries as new as yours are, would be experiencing that, but like I said, all it might take is a bad connection somewhere, a bad crimp on a terminal, corrosion/higher resistance at a connection point, etc.

And just as a reference point, I can see voltages on each cell in my battery because of the functionality of the BMS that I used when I built the battery. When I am fully charge, the difference in voltage between the four cells is normally 1 or 2 millivolts. In decimal form, that is .001 volt to .002 volts That would be a good top balance between cells. In terms of balance between two different batterys (comprised of 4 cells each), you might see
something like .10 volt difference when fully charged, but hopefully not even that high. Hope this helps and let us know what you are finding.