58 replies to this topic

[buckland]

Well that is hopeful news. The fan has been on for four hours and the cells are still balanced. I will let it run another two hours then plug in the 100 W panel to charge. I assume a controller that is not a mppt type (sunsaver 20) has a different way to handle the charge. Will see how this recharge goes. Thanks for the background explanation. It helps the understanding of what I am seeing.

[CougarCouple]

[Remember, the display on the balancer is only guessing at what the battery SOC is based on the voltage it sees, which doesn't work very well on lithium to start with, and really doesn't work when the battery is not at rest. When you are loading it down with the inverter, the voltage drops, so the balancer display drops the SOC because it is only a linear function of the measured voltage. When you are charging the voltage rises, and all of a sudden the balancer thinks the SOC is high.]

All that makes sense above.
Is the charger being used the problem?
What would be a reasonable time a depleted lithium battery take to charge to 100%.

The comment about cycling thru several charge cycles, what is the reason for that?

Thanks in advance
Russ

[Vic Harder]

All that makes sense above.
Is the charger being used the problem?
What would be a reasonable time a depleted lithium battery take to charge to 100%.

A depleted LeFePo4 100AH battery will charge as fast as you can feed it... Up to 1C or 100A) at the 4A that Buckland is feeding it, 25 hrs with no draw.  

Edited by Vic Harder, 22 June 2020 - 02:59 AM.

[buckland]

That makes sense... I appreciate your math in all your explanations... takes care of the "why?".  

[Stokeme]

This is non scientific, but the one experience I had with a totally drained LFP4 system, (50w & 100w in parallel) which btw scared the crap out of me, was that it charged at a snail’s pace at the beginning, and as the voltage increased, the rate of charge seemed to slowly increase. The cells at higher voltage seem to release energy slowly & efficiently. They also charge effectively & evenly as well. But starting at very low voltage, as I watched charging progress with the internal Bluetooth modules, the cells were not as orderly, even or as efficient.
I used only my (240w) solar panels. It happened to be a uneven mix of clouds & sun all that week. It took 2 1/2 days to reach 99% SOC. I have a 20amp LFP4 Charger but I was curious how long only Solar would take to fully charge.
Throwing this out (sorry if superfluous) as one aspect I encountered with Lithium battery charging. Typically my System only drains 8 - 12% by next morning. By 1pm each day it’s back to 99% SOC.

Edited by Stokeme, 24 June 2020 - 03:51 PM.

[Vic Harder]

I got my dual 100AH BattleBorn's down to 8% SOC this week.  Driving home today, the solar panels were putting 375W into the batteries.  Might depend on the BMS of the battery?

[CougarCouple]

Morning Vic
Was that 375 watts just your panels, that looks pretty impressive to me.

Russ


ps thanks for the earlier response on time to charge battery.

[Vic Harder]

yup, just from the one panel.  I was startled too.  

[buckland]

Hello Vic
When you are able to get to the Canadian Maritimes you’ll get to appreciate Northeast weather! After a Covid test I was allowed to travel to Maine ... we are up on the Canadian border. Lots of bugs and rain. And now to the battery point. I have two canoes on the roof and it has rained solid for three days. The one Battleborn battery heroically has lasted but this evening I turned off the main camper electric knob as my Victron showed 11.85 V mighty low? We bought ice for the fridge.
When there was no juice from panels the Victron app stated that the charger needed 5volts higher than the battery to initiate charging. The panels suffered to be at 15 v. ( I have a portable 100 w panel and it could not produce that voltage due to clouds.
The second thought is about alternator charging. It seems it is not happening. I have a 2016 truck and being computer controlled I am sure it won’t reach 5 v over battery.
My truck battery indicates on the dashboard it goes on and off between 12.2 and 15 v almost in a computer generated on and off pattern.
Perhaps the Victron is not permitting alternator charging? Or is it the. Blue seas ACR thats is not allowing charge?
Electrical puzzles.
We are heading to a remote cabin for another week. Rain for two more days.) when we get there tomorrow I take off the boats and will also plug in additional panel to hopefully get the battery back up. Might have to consider a second battery.
Rob (aka Buckland)

Edited by buckland, 29 June 2020 - 10:13 PM.

[Vic Harder]

Hey Rob, yes... we are looking forward to a trip to the east coast.  Not sure that will happen in 2020 because of Covid, but.... 

 

Re: canoes on top and rain.  Yes, I experienced that this week too, hence the 8% battery SOC after 3 days of using our 1800W induction cooktop draining our 200AH of BBorn batteries.  I was worried about the BMS putting the batteries in shutdown.  That happened once already during testing.  I had to disconnect the batteries for a few minutes to get them to reset and even accept a charge.

 

Regarding the 5 volt threshold for charging.  PITA that, no?  

 

To get more juice from your panels, you might want to consider going in series vs parallel.  Or have you done that already?

 

Victron is only between PV panels and battery, so it won't be interfering with alternator charging.  That's the Blue Sea ACR's job.    Are you saying that on the truck dash you can see the truck battery oscillating between 12.2 and 15 v?

Edited by Vic Harder, 30 June 2020 - 02:24 AM.