Lithium Battery charging

Thanks Vic you are most probably right ... it would be overkill. I guess I have the concern that my dyi battery might in some way affect the Battleborn battery should the dyi battery fail somehow. Not that I wear suspenders and a belt but like to err on the side of caution.
 
I would have those concerns as my ignorance necessitates caution. Also whether or not being run in parallel has, previously/currently, affected incoming A, or outgoing Ah. How does the resting V compare?
 
Battleborn seems to go all the way to 14.4 then with everything off in camper in the evening it is down to 13.4-5 the DYI goes down to 13.35 ... so both pretty close
 
buckland said:
Battleborn seems to go all the way to 14.4 then with everything off in camper in the evening it is down to 13.4-5 the DYI goes down to 13.35 ... so both pretty close
Click to expand...
Those numbers make sense... given what your charge and float voltages are set to (if you are using numbers I have seen recommended here and elsewhere).
 
Another question about charging. Reminder I have a Battleborn and DYI LiFePo4 batteries in parallel. Currently camper main is on but fridge is off. Not much on but smoke alarm.
I notice through the Victron app the batteries sometimes are up to 14.2 but then overnight they are between 13.2 to 13.4. What makes the loss? Is the LiFePo4 setting on Victron 100-20 keeping them at 12.3 v for some reason? My settings are adsorption 14.2 and float at 13.5.
 
buckland said:
Another question about charging. Reminder I have a Battleborn and DYI LiFePo4 batteries in parallel. Currently camper main is on but fridge is off. Not much on but smoke alarm.
I notice through the Victron app the batteries sometimes are up to 14.2 but then overnight they are between 13.2 to 13.4. What makes the loss? Is the LiFePo4 setting on Victron 100-20 keeping them at 12.3 v for some reason? My settings are adsorption 14.2 and float at 13.5.
Click to expand...
I dunno, but I think the key phrase might be the last one... "My settings are adsorption 14.2 and float at 13.5.". That would mean to me that if the batteries are fully charged and resting (float) you can expect to see the (overnight/resting) voltage be 13.5 or so. "Sometimes" that bounces up to 14.2 when the controller is topping them up.

Make sense?
 
I think so !
I am always sure of one thing and that is I don't have enough knowledge on the subject.
The difference between 13.2 and 13.5 is a lot of acvxzperage is it not with LiFePo4 batteries?
Sees to vanish... I wonder if it is not the fact that the DIY draws the Battleborn down. I have to balance
often as one cell seems to always be the outlier.
Thanks Vic
 
buckland said:
I think so !
I am always sure of one thing and that is I don't have enough knowledge on the subject.
The difference between 13.2 and 13.5 is a lot of acvxzperage is it not with LiFePo4 batteries?
Sees to vanish... I wonder if it is not the fact that the DIY draws the Battleborn down. I have to balance
often as one cell seems to always be the outlier.
Thanks Vic
Click to expand...
The more I learn the more I realize I know very little.

I think you meant to say "The difference between 14.2 and 13.5 is a lot of amperage is it not with LiFePo4 batteries?" And I agree, that seems like a big difference. However, the way I see it is that 14.2 is the voltage necessary to CHARGE the battery to a resting level of 13.5V. So when the charger is active, you see the voltage it is putting out, not the level that the battery is at.

I'm not sure how the two LiFePo4 batteries would interact if they are not identical. They will always try to be in balance with each other though
 
Interesting and very informative thread!

I am in the process of upgrading our solar/battery system after our flexible panels gave up the ghost. We will be installing 2, 100 watt solid panels from Renogy and a second BattleBorn battery. I’m hoping this will allow us to stay off the grid for an extended period of time.

I am also building my Jeep Gladiator into a more remote camping rig, possibly going to Baja when things open back up. In doing my research for that build the Redarc BCDC 1225 controller with solar input gets high marks as they have been around a long time.
https://redarcelectronics.com/products/dual-input-25a-in-vehicle-dc-battery-charger

We are hoping to do the Nova Scotia/ Newfoundland/Labrador route next summer if things get straightened out...maybe we can have a WTW rendezvous on the East Coast!
 
A DC-DC charger can be used instead of the ACR. If you currently don't get enough charge current from your alternator, a DC-DC will fix that. It will also address the issue (although I don't consider it an issue) of the higher lithium resting voltage keeping the ACR combined most of the time, at the expense of loosing solar charging of the truck battery.

I sound like a broken record here, but would go with the Victron DC-DC over either the Redarc or Renogy options. The two big advantages of the Victron is the configurable output (dial it in for lithium or whatever comes next) and the remote monitoring.
 
The difference between 13.5 and 13.2V is actually surprisingly little on LiFePO4. The 13.5V reading is the 'surface charge' on the cells, and no real energy is stored here. It is kind of like with a lead acid, when you take it off the charges it will sit at 13.xV for a while, but as soon as you load it, it drops to 12.6V.

One of the advantages of lithium chemistries is that the voltage is constant as you discharge the battery. A consequence of this is that reading the voltage tells you very little about the state of charge:

discharge.jpg

From: https://www.powerstream.com/LLLF.htm


Note this is for a single cell, multiply by 4 for a 12V battery. There is only a few % in the drop from 13.6 - 13.2V, and then the voltage only changes by 0.1V over the next 70% of the battery capacity.

buckland said:
I think so !
I am always sure of one thing and that is I don't have enough knowledge on the subject.
The difference between 13.2 and 13.5 is a lot of acvxzperage is it not with LiFePo4 batteries?
Sees to vanish... I wonder if it is not the fact that the DIY draws the Battleborn down. I have to balance
often as one cell seems to always be the outlier.
Thanks Vic
Click to expand...
 
I need broken record to get it through to me! Once again thanks also for the graph. Pretty amazing difference. I think I’ll go to the dc dc charger as my ACR does not help much.
 
I just installed a Victron Orion DC-DC charger in my Alaskan, replacing my Blue Sea ACR as I had switched to Battleborn. My Victron version was not the smart version ( blue tooth) and had a potentiometer on the side to set the output voltage. A bit of a pain in the ass as I had to get my alternator to put out over 14 volts to set potentiometer to correct level. I set it at 14.2 volts. The smart versions were back ordered when I got my Victron. So far it seems to be working out fine. Hopefully it will be a set it and forget it as I have to remove it to get to the potentiometer. Victron makes good products.
 
Rando
Can I use the positive wire currently going to the ACR to go to the DC DC charger?
 
rando said:
I sound like a broken record here, but would go with the Victron DC-DC over either the Redarc or Renogy options. The two big advantages of the Victron is the configurable output (dial it in for lithium or whatever comes next) and the remote monitoring.
Click to expand...
Rando does the Victron model allow a solar input along with the truck battery to charge the house battery? I didn’t see any mention of that.
 
The Victron is alternator charging only. Generally the DC-DC chargers that support solar don't do a great job of it as the solar is an afterthought and is just repurposing the DC-DC electronics. As a result they typically don't support series panels, and the MPPT algorithm isn't that good. I guess it is kind of a free 'bonus' so you can't complain too much.
 
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