70 replies to this topic

[buckland]

Plugged in the 100W portable flex. Watched the Wattage jump as well as volts/amps in battery. It is a mostly cloudy day so it will take awhile..... Take a screen shot of the App screen the minute I plugged in extra panel.

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[buckland]

After 4 hours on the extra panel... an initial jump... the voltage settled back down at 13.5 (the Isotherm fridge draw no more than 3 amps when on). So I unplugged the extra panel and plugged in the shore power with the IQ4 (for LiFePo4 battery management Iota) and it started charging right off and I will leave it on for a few hours then unplug after checking the voltage. I took photos of the controller app page that monitors the ins and outs. For what it may be worth for those that know more than I maybe there is a pattern in there I do not see.

It's either the battery can't hold the charge over 13.5 or...... I'll describe when each photo was taken:

 

1st was when I plugged in extra solar panel

2nd when I plugged in the shore power

3rd after 10 minutes plugged in it fell back down to 13.5

4th a little History of the day

5th live goings on

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Edited by buckland, 01 September 2019 - 10:01 PM.

[Vic Harder]

What are you wanting to see?   A higher resting voltage?  13.5 is what Victron/Battleborn recommend for a float voltage, and your charger is still going strong by putting 8.5A into the batteries at that voltage. That's good, no?  

[buckland]

Well I was expecting the battery to charge up to 13.8 or 14. V. Even with everything off in camper and the Shore power plugged in it won't charge (and hold it) higher than 13.45

I was looking at the LiFePo4 charge chart and it seemed like that a higher charge was normal.

 

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[Vic Harder]

This may help.  Screen shots from my rig this morning

 

 

 

 

97% on the Victron BMV = 13.55 V

Edited by Vic Harder, 02 September 2019 - 06:08 PM.

[buckland]

Thanks for taking the time Vic. That is what I want to see in the AM too but mine is 13.1 V (just the fridge on all night) If I charge all day solar or if I plug in shore for 5 hours I will get up to 13.56 V (when the fridge is not running). That is about as high as it goes but not for long. I (tho this is only a gut feeling) think I have ...out of the 120 cells in packs of 30, have a few weak cells that have limited the pack. If that is all that it is I can live with it. I still have the empty battery box from having 2 AGM batteries. Maybe next season... when I hope to do a coupe longer trips... I'll spring for a Battleborn and have both in there.... still lighter than 2 AGM.

[rando]

From the first picture - 13.61V @8.5A, it looks like you have your absorption voltage on the charge controller set to 13.6v (there is more solar power available, but the charge controller is choosing not to use it).   In which case the solar is doing what it should, get the battery up to 13.6V and hold it there for what ever your absorption time is.   

 

If you want the solar voltage to go higher than this, then you need to raise your absorption voltage in the charge controller settings.  That being said, if you get the battery up to 13.6V, then you are at 90% + state of charge, so you should be fine.  

[Vic Harder]

From the first picture - 13.61V @8.5A, it looks like you have your absorption voltage on the charge controller set to 13.6v (there is more solar power available, but the charge controller is choosing not to use it).   In which case the solar is doing what it should, get the battery up to 13.6V and hold it there for what ever your absorption time is.   

 

If you want the solar voltage to go higher than this, then you need to raise your absorption voltage in the charge controller settings.  That being said, if you get the battery up to 13.6V, then you are at 90% + state of charge, so you should be fine.  

rando, can you revisit how you set your BMV and  MPPT controller to self-limit charging to 90% or so?

[Stokeme]

As another reference point (post #16) my absorption is set to 14.4. Both my batteries (in parallel) float @99% capacity when full. This has been what is shown as “fully charged” as displayed by the internal Bluetooth module in each Batterry. On 08/22/19 the resting V was 13.48. On another post 07/27/19 it was 13.45. I have not documented V during charging. My memory is ... charging does reach 100% with a higher V & then settles @99% with a lower V.
I have a question regarding my post #16. When my Batteries were inadvertently & completely drained, why did they abnormally, initially, charge so slowly? (There may have been extenuating factors) Is this typical of LFP4? Would charging accelerate, as the V began to increase, closer to its full capacity? My usage so far, except for this once, has been ~15-18%/night. I have always been impressed how efficient the charging has been typically. Why so seemingly slow when drained? It causes some off grid concerns. Excuse my lack of electrical know how.

Edited by Stokeme, 03 September 2019 - 12:52 PM.

[buckland]

Thanks Lars. I had changed the absorption to 14.3 as seen below and the time at 30 minutes. I think I will increase the time to an hour. (kinda feels like I'm just jiggling the butterfly valve on the old chevy... see what happens!)

Attached the settings and the monitor this AM... Voltage still only 13.2

 

 

 

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Edited by buckland, 03 September 2019 - 01:43 PM.