ELcon TC charger

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offgridQLD
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ELcon TC charger

Post by offgridQLD »

I recently sold a ELcon TC charger it was listed as a (16 cell Lifepo4 58v - 25A) It was part of a package with some Calb 40ah batterys that I purchased. I didn't need the charger so I sold it to a friend in NSW who intended to use it for charging 48v - 55AH gel batterys for his aquaponics pumps.

So befor posting it to him. I connected it to my small 40ah lifepo4 bank to test that it worked ok. It started charging and I watched it until it reached 58v and continued to monitor it until the charge current had dropped and the green led had come on indicating 100% SOC. So at that point I turned it off and considered it to be all good and the max CV stage he would see would be 58v. Then I got the following response back from my my friend.

"I was going to email you about its regulation, which seems a bit dodgy to me. I have it charging 48V 55AH of gel cells on the large aquaponics system 8 times per day for about 15-20 mins each time and when it starts the Absorb stage of regulating it pumps the voltage up to 60.8V, then lets it drop to 57.7V before going to 60.8 again over a cycle of 5 or 10 sec. 60.8V is a bit high for the gel batteries, but hopefully it wont do too much damage, but I'm not sure I'd like it on my Lithiums!"

My response

"That's strange,
Is it actually charging at 60.8v as in bringing the bank up to that voltage? I followed it a few times connected to a 40AH - 48v lifepo4 bank (just to test it befor I posted it ) and it maxed out at a tad over 58v (58.2..something like that) "


"Yep, the battery was going to 60.8V before dropping to 57.7. It seems to be a very slow PWM regulation- normally I would expect a PWM charger to regulate at the voltage set points at a reasonably high frequency, this is hundreds of times slower than I would expect, or have seen with any other charger. There was a stage where it went to just over 58V before dropping back as well, but that isn't a worry. I cant remember if it was doing that before or after the stage where it went to 60.8V.
If you can discover any clues about it that would be great"

So unfortunately I had very little time with the charger so have little experience with it befor passing it on. Can anyone more informed on them shed some light on what this charger is doing with it's behavior going to 60.8v described by my friend above.

Kurt

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coulomb
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ELcon TC charger

Post by coulomb »

Kurt,

all I can think of is that charging 8 times per day is too often, so the cells are always full, and maybe their internal resistance goes up near the top of charge. [ Edit: and this is somehow upsetting the Elcon charge algorithm. ] Even so, the voltage should regulate much better than that.

Maybe he should just leave the charger on all the time. The Elcon won't stay float charging with standard firmware, but I believe it might start charging again when the voltage drops low enough. (I should check the code; I'm rusty on that now.) However, the return to charge voltage, designed for LiFePO4, may not work well for lead acid gels.

I do intend to update my Elcon Firmware pages on DIYelectriccar.com soon. Time availability has been crazy lately. When I do, if he's handy with electronics and software and is brave enough, he could replace the firmware with lead acid "curves" better designed for his battery.
Last edited by coulomb on Fri, 17 Jul 2015, 05:33, edited 1 time in total.
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offgridQLD
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Joined: Tue, 23 Jul 2013, 16:05
Real Name: Kurt
Location: Fleurieu Peninsula, SA

ELcon TC charger

Post by offgridQLD »

Thanks Coulomb, I will pass that onto him . Not sure why he is charging 8 times a day. Now you mention it I'm keen to know why.

Kurt
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