Lifepo4 ac charging issue

[LanceBuilt]

I have a 200ah lifepo4 16s battery for our off grid home.
Having issue with ac charger, this is an all in one 6kw 48v sw inverter, 60a charger and ats, same as aims but black and branded as sun gold power. the charge amperage is all over the place, at each sample it will be 60 then 5 then 0 then 72, just all over the place. Have tried different charger presets, even has one for lifepo4, but to no avail. The lifepo4's charge just fine from the solar cc's. I want to get the most into the batteries I can when on ac to limit genset runtime, I'm probably averaging 30a from this 60a charger. I'm wondering if I need to purchase a stand alone charger or perhaps there is some other solution.

 

[John Frum]

Please post a product link for you inverter.
How are you measuring charge current?
Do you have a shunt based battery monitor or dc clamp meter to rule out faulty instrumentation?

 

[LanceBuilt]

Yes indeed,
inverter,
https://www.amazon.com/gp/product/B07YZ5J952/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Meter,

Amazon.com

Shunt based, Also have an inductive dc clamp meter which confirms the swing in amperage, as does the bms app.

 

[John Frum]

I'm not sure what the problem is.
Possibly a problem with the ac supply or with the charger.
Can you beg, borrow or steal another ac charger to see if it also has problems with the same supply?
What happens if you reduce the charge voltage?
What happens if you reduce the charge amperage?

 

[LanceBuilt]

I don't have access to another charger. The charger has no voltage settings aside from a selection of presets, it does have a variable knob for amperage. Turning this down does help, but then were charging at a lower amperage. The charger is picky about the incoming power and will shut off the charger if the voltage or frequency is out of range, but that is a complete shut off and reboot of the charger. The genset is pretty large at 20kw.
I noticed that the voltage occasionally spikes as well briefly approaching 70 or so, Since I have the resource I turned on my opportunity load and adjusted it to come on only when the voltage exceeded the expected voltage of that preset which is 56. This has helped to stabilize the voltage and the amperage, though still not seeing a solid 60a, more like 40a, this has been the best result so far, of course I shouldn't have to resort to such chicanery.

 

[John Frum]

Turning this down does help, but then were charging at a lower amperage.

Hmm could still be either the charger or the supply.
Is mains power available so that we can do differential analysis for the generator?

 

[LanceBuilt]

No shore power, totally off grid, but I do have another 10kw generator/welder, that I will try, though it may be a few days before I could move things around in order to run that test. Thanks for your help by the way

 

[LanceBuilt]

Problem solved, actually multiple problems solved.

I also had a problem with the bms shutting off intermittently and inexplicably during a constant mild discharge.
All of this was caused by a bad connection/s at the battery buss bars. The original hardware were 6mm bolts that were too long, I used washers to make up, don't do this, use studs and nuts! Lesson learned at considerable expense of time.

The only way I figured out the problem was, I eventually replaced the daly bms, assuming it was at fault. The new jbd bms app showed that the bms was cutting the charge ability constantly, like every second or two, causing the surging during charge. It also has a better graphic/bar graph for illustrating cell voltages. This led me to a particular cell's connection, and found the problem. The daly never indicated it was cutting the charge ability, nada, though it was obviously doing the same. Will keep the daly as a spare.
Once I replaced the bolts with studs, the battery started working like never before. Very pleased now with these lifepo4's a massive improvement over the old lead acids, more like filling up a tank than charging a battery, compared to before.