generator and alternator charging at the same time

[dave17352]

I have a new LION ut1300 battery. It can take a charge at 100 amps. So lets say I am running down the road and I have the generator on so there are two charging sources heck lets throw in solar too. So there are three sources of charging.

Alternator generator/converter and solar. Is there a problem. I don't think so, but any advice from those that know and could explain how this works would be appreciated.

Thanks in advance
Dave

[3_tons]

You might consider a inverter-charger, LFP compatible with 100 (or more...) charge amps - problem solved...

3 tons

[BFL13]

Right, so it is still about the various voltage diffs between the chargers and the battery, but with LFP as long as they are all above the flat part of the voltage, each will all add some of the total amps in proportion to its voltage difference.

The lowest will not drop out so soon since the battery voltage is not going to rise up and pass its voltage so soon like with FLAs.

[Freep]

BFL13 wrote:

As the battery voltage rises from being charged, amps will start to taper from the lowest voltage charger of the three until amps get to zero when the voltages are the same, then amps will be tapering on the next highest voltage charger until battery voltage rises to its voltage, and now only the highest voltage charger is supplying amps (to its current limit).

Keep in mind that with LiFePo4 batteries the charging curve is mostly flat. So your battery will stay at 3.3v for a very long time until it hits the knees and then it will shoot up. This is why a BMS is critical. Also LFP batteries in general will take a 1C charge, though some take 3C.


So it's not really a taper. It's more like a firehose and then suddenly(from a voltage perspective) your battery is full.

[pianotuna]

dave17352 wrote:
Also the converter has over current protection. Perhaps that is what is cutting the power. The battery handles 90 amps from the alternator no problem.

Did you run wire directly to the alternator? What size wire? What size fuse?

[MEXICOWANDERER]

Don't forget to factor terminals studs and connections into total resistance. A good way to discover reactive resistance is with an IR gun. LOAD for 10 minutes then scan. Warmer specifics should be examined and rectified. Anything made of brass should be treated with suspicion.

[BFL13]

Can you describe in more detail what happened when it "cut out"? Did the converter and battery just sit there with no current flowing all of a sudden (on what meter?), but the 120v to the converter was still on ok?
Was there still voltage at the converter's DC terminals but no amps flowing?
Do you get a read-out from the BMS anywhere that showed something like a code that means a particular thing? What did you do after to get it all going again? The converter didn't fry anything or it would not work again.

The converter is "current limited" but there is no actual over-current protection that shuts it down AFAIK. Are you suspecting a "surge" of current because of the low R of the LFP? You can fry the input thermistor with a surge but that makes smoke and flames (BTDT ! exciting! 😞 )

With the 90 amps from alternator, were you able to see what voltage the BMS was seeing at the time? Was it lower than the converter's voltage?

--Trying to figure this out as an interesting mystery, plus maybe have more info to pass to Errin if you haven't already. Tomorrow is a working day so they might be able to look into it.

[dave17352]

8 is good for a 1 foot run. Also the converter has over current protection. Perhaps that is what is cutting the power. The battery handles 90 amps from the alternator no problem.

[BFL13]

Errin says also they are looking at a new power centre, don't know what converter it would have.

I guess calling a converter an LFP one is just for the "Sales" people, since the LK model already can do any LFP spec plus any other type of battery's specs.

if you can answer the last set of questions and try out the other "set" of converter-battery, then Errin could read all about it here (a link to this thread by email) and do whatever needs to be done.

The converter has nothing in it that can cut out and cut back in that I know of. It has a 120v fuse. Other things in it can fry.

OTOH, the BMS can do that action I think. IMO the first thing is to find out if possible if it is the BMS doing it or not. If it is with the batt you have but not the other batt, then that might be a warranty item for that batt. Maybe that converter is duff, but the other other one is not.

#8 is too skinny for the 55 amper. Could be why only 50 amps. I use #4. #8 has the ampacity in theory but I had fewer amps with it, and good amps with the #4.

[dave17352]

Power max is coming out with a converter for lithium in the near future.

[BFL13]

Thanks, it seems weird for sure. What did it do exactly when it "cut out"? Did the green light stay on, eg ? It worked again later, so how did you get it going again?

Are you sure it was the converter that "cut out"? I wonder if the BMS for some unknown reason isolated the battery, if it would look like what you saw.

Is there a re-setting DC breaker between the converter and battery that was "cutting out"? They can trip at lower amps than they are rated for, as was mentioned in another thread here recently. That would explain why it works ok at lower amps?

You might try the spare converter on the other battery your son-in-law has to see if it does the same thing. That would be very good info either way.

PowerMax and Lion might have to get together on this to solve it if the other battery and converter do it too.

[dave17352]

BFL, I spoke with the same fella you did probably. He also told me he would ask as of yet I have not heard back from him.
To explain this is exactly what I did. I drained the ut1300 to almost empty. I hooked the converter directly to the battery with foot long 8 gauge cables. I set the voltage at 14.6 and left it on the constant voltage not 3 stage. The converter fired up and did indeed charge at about 50 amps for a short time and then cut out. I am talking after about 1 minute. I was also monitoring the voltage at the battery which was slightly lower than at the converter. So then I turned up the voltage so I was getting 14.6 at the battery. I cut out quicker. Then I turned down the voltage enough to where it would run at about 40 amps and that worked. So then after a good bit of experimenting around I decided I would mess that with second pot. I found that indeed did adjust the current up and down. Of course with the higher current it would then cut out quicker. So in the end I installed in my wfco and adjusted it where I will get just about 30 to 35 amps when the battery is drained about 20 percent. It starts to slowly drop as it tops off. I have the voltage set at 14.6. I am perfectly happy with this. Lion suggest a 45 amp charge rate but also points out it can take up to a 100 amp charge rate. The bms on LION shuts off current at 14.7 on the dot. I found this in my experimenting with the converter.

When I did have the alternator in the system I watched the battery getting charge at 90 amps while running the motor, I drove for about 15 minutes and that battery was amazing just guzzling the amps. I bought this battery for the convenience and the cool factor a lot more than a need factor. If I ever need a quick charge I will just put the fuse back in and let the alternator charge it up. With just one battery (my son in law has the other one) I am not to concerned with using the alternator once in a great while.

I have bought other powermax converters in the past and have been pleased. I will have the other new converter in my rig for a back up.

So to sum it up I could get higher current just not the full 55 and I would have to use higher voltage which as the battery topped off it would cause the bms to shut it down and I don't want that to happen.

Now you know the rest of the story. 🙂

[BFL13]

Not sure what is happening with your converter. Did you twiddle the second pot inside? The PowerMax guy does not know what that pot does for sure; he will ask his engineers.

He did say he knows lots of guys using LIONs with the LKs set to 14.6v and it has been working out great for them.

If you did twiddle that second pot IMO try to put it back OEM and the pot in the hole to 14.6. You should be getting 55 amps. What does the second 55 amper do? You could copy the second pot's angle around in the 55 amper not twiddled to find OEM position.

If the low amps problem persists, please post about that some more. No doubt PowerMax will want to know too and put you right as needed.

[dave17352]

Around 120,I did not check though.

[pianotuna]

dave17352 wrote:


When I ran the converter next to the battery it definitely would cut out at higher amps. I did this several times. It would run up to 50 plus amps and cut out. When I lowered the voltage therefore less amps it quit cutting out. I could get higher amos but I am okay with 30 plus.

What was the input voltage to the converter?