generator and alternator charging at the same time

There is a SEARCH function on all forums world-wide where you could have found this very same question asked 100 times already....
You can run multiple charging sources at the same time.
IF you have li-ion batteries then you will need solutions between the alternator (not made to charge these batts) and your batts.

mr_andyj wrote:
There is a SEARCH function on all forums world-wide where you could have found this very same question asked 100 times already....
You can run multiple charging sources at the same time.
IF you have li-ion batteries then you will need solutions between the alternator (not made to charge these batts) and your batts.

So what’s your point? I like this forum.

BFL13 wrote:
Interesting about the 55 amper LKs I will check that out. I suspect the 30 amps instead of 55 is from being in the WFCO's location and it has long thin wires to the battery. My 55 amper does 56 amps but I use short #4 wires with it.

You can parallel the two 55 ampers running off the big gen and get 110 amps that might be under 100 with voltage drop if you want to do 1C on the LFP that way.

EDIT--AFAIK the converter has no high current power shut down; it is just current limited to its rated current (and a bit more). Did you mean the 120v power to the converter is shut down by a generator shut down controlled by the BMS or Victron?

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.

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?

Around 120,I did not check though.

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.

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. :)

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.

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

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.