Battleborn - charge settings

[ri-f]

Thanks Rich, I missed this source...but then I miss alot!

Phil

Well, no Phil, it's not hard to miss. Their source is a moving target and sometimes obscure to find. I believe this was their latest revision. Also, I updated my last post with the settings that I use, which have worked out very well for me, to date.

Rich

 

[Wallowa]

Rich,

Yes...on "moving target"...persisted until I actually was talking to a BB Tech today, Derek; he was very helpful and that way I did not have to sift through a ton of emails or posts...in fact he said he had to make a BB video today, so perhaps it will be an updated version of what is currently on their site..

Will appreciate seeing you settings...

Thanks..Phil

 

[ri-f]

My settings for the BB 100AH follow:
charged voltage: 14.2v
absorbtion: 14.4v
float: 13.2v
max charge current: 30A
tail current 4.00%
charged detection time: 3m
puekert exponent: 1.05
charge efficiency factor: 99%
current threshold: 0.10A

I never plug in to shore power. My solar keeps battery topped off year round. My resting volatge is typically 13.4-13.5, and my max voltage is typically 14.4-14.5 at these settings. If I was storing the camper in a barn, I would charge up the battery to 100%, then disconnect the cables and let it rest and expect a 3-5% drop in SOC per month, which would probably equate to a 50 % discharge over about a year's time.

Rich

Phil, these are my settings (see above). I tried a slightly higher bulk and absorbtion, and a slightly higher float previous to this, but I find that these settings appear to work best for me. It keeps my 100AH BB (after it's topped off) resting, overnight until the sun comes out again at close to 13.5v and never goes above 14.5v during the daytime with these settings. Again, I only charge with solar (two 160W Overland semi-flex panels and a Victron 100/30 mppt controller). With solar handling the charging, it seems as if float isn't even a recognized parameter, as it would be with a constant shore power charge. Plugging in to shore power might necessitate a slightly higher float (say, something closer to 13.4-13.6v as BB suggests, I don't know since I don't do that), but solar fluctuates the voltage throughout the day, nicely, and personally I think it's healthier for the battery than keeping it on a constant float. At least that's my opinion. Anyway, it seems to work for me. Rich

 

[JimBow]

Phil, these are my settings (see above). I tried a slightly higher bulk and absorbtion, and a slightly higher float previous to this, but I find that these settings appear to work best for me. It keeps my 100AH BB (after it's topped off) resting, overnight until the sun comes out again at close to 13.5v and never goes above 14.5v during the daytime with these settings. Again, I only charge with solar (two 160W Overland semi-flex panels and a Victron 100/30 mppt controller). With solar handling the charging, it seems as if float isn't even a recognized parameter, as it would be with a constant shore power charge. Plugging in to shore power might necessitate a slightly higher float (say, something closer to 13.4-13.6v as BB suggests, I don't know since I don't do that), but solar fluctuates the voltage throughout the day, nicely, and personally I think it's healthier for the battery than keeping it on a constant float. At least that's my opinion. Anyway, it seems to work for me. Rich

Thanks for the info, Rich.
If you go to the Victron website, they have a calculator for sizing a solar charge controller. For 320 watts, the calculator recommends the 100/20 controller. Is there any advantage to the 100/30 controller? Other than it would allow for adding more solar panels.

Another question if you don't mind. You have the "charged voltage" set at 14.2 volts. Is that for the battery monitor (shunt)? The manual calls for setting it to 13.2 volts for Li Ion batteries. That's what I set mine to. I don't really understand that setting.

 

[ri-f]

Phil, these are my settings (see above). I tried a slightly higher bulk and absorbtion, and a slightly higher float previous to this, but I find that these settings appear to work best for me. It keeps my 100AH BB (after it's topped off) resting, overnight until the sun comes out again at close to 13.5v and never goes above 14.5v during the daytime with these settings. Again, I only charge with solar (two 160W Overland semi-flex panels and a Victron 100/30 mppt controller). With solar handling the charging, it seems as if float isn't even a recognized parameter, as it would be with a constant shore power charge. Plugging in to shore power might necessitate a slightly higher float (say, something closer to 13.4-13.6v as BB suggests, I don't know since I don't do that), but solar fluctuates the voltage throughout the day, nicely, and personally I think it's healthier for the battery than keeping it on a constant float. At least that's my opinion. Anyway, it seems to work for me. Rich

Thanks for the info, Rich.
---------------------------------------------
If you go to the Victron website, they have a calculator for sizing a solar charge controller. For 320 watts, the calculator recommends the 100/20 controller. Is there any advantage to the 100/30 controller? Other than it would allow for adding more solar panels.

Another question if you don't mind. You have the "charged voltage" set at 14.2 volts. Is that for the battery monitor (shunt)? The manual calls for setting it to 13.2 volts for Li Ion batteries. That's what I set mine to. I don't really understand that setting.

JimBow - I sized my controller with the potential for adding an additional panel of the same size and type, later, if I wanted it. The 100/20 would have been fine otherwise. If I were to add a portable panel, down below, I would probably install a smaller, second Victron controller if the portable panel only had a PWM controller. Again, probably not necessary, but I like Victron MPPT controllers.

As for the charged voltage, BB suggests ~0.1v to 0.2v less than the absorption voltage. I set my absorption voltage at 14.4v, that's why I have 14.2v (14.4v - 0.2v = 14.2v) for the charged voltage parameter. 13.2v to 13.6 volts is the range BB suggests for float voltage. I haven't seen the manual you're referring to, but 13.2v is too low. If you have it set to that, I don't think you'd ever see a full charge. Hope that helps.

Rich

 

[Vic Harder]

If you're interested, this is the BB manual, which spells out, pretty clearly, their charging parameters and suggested settings, and as has been suggested their BMS high voltage cutoff trigger is > 14.7v:

https://dragonflyenergy.com/wp-content/uploads/2020/11/10012-Manual-FINAL.pdf

My settings for the BB 100AH follow:
charged voltage: 14.2v
absorbtion: 14.4v
float: 13.2v
max charge current: 30A
tail current 4.00%
charged detection time: 3m
puekert exponent: 1.05
charge efficiency factor: 99%
current threshold: 0.10A

I never plug in to shore power. My solar keeps battery topped off year round. My resting volatge is typically 13.4-13.5, and my max voltage is typically 14.4-14.5 at these settings. If I was storing the camper in a barn, I would charge up the battery to 100%, then disconnect the cables and let it rest and expect a 3-5% drop in SOC per month, which would probably equate to a 50 % discharge over about a year's time.

Rich

Rich, are you sure about the Tail Current? I had mine at 1%. Other than that, my settings are the same on all my Victron devices:
100/30 MPPT, Orion 12/30 Dc-DC and Ac to DC 25a charger.
Absorb - 14.2
Float - 13.2

 

[ri-f]

Rich, are you sure about the Tail Current? I had mine at 1%. Other than that, my settings are the same on all my Victron devices:
100/30 MPPT, Orion 12/30 Dc-DC and Ac to DC 25a charger.
Absorb - 14.2
Float - 13.2
---------------------------------------------------------------------------------------

Vic, I'm quite sure. I've been through this with Battle Born in the past and they recommend a tail current of 2% to 4%. AM Solar recommends a tail current of 2%. Victron suggests 4%. There is a Victron BMV-700 series instructional video that goes over a few of these points. I'm including part of a video text transcript below regarding tail current for applications with fluctuating charge currents (i.e., solar charging).

https://www.victronenergy.com/blog/2017/04/13/instructional-video-how-to-optimise-the-bmv-700-series-sync-parameters/


...In solar systems or other applications with fluctuating charge currents, the ‘charged’ voltage should be set only slightly below the absorption charge voltage (for example: 14.1V in case of 14.4V absorption voltage). This will prevent the BMV from switching prematurely to 100% state of charge. The Tail current is expressed as a percentage of the battery capacity. When the charge current has dropped below this setting, the battery is considered as fully charged. The default setting is 4%, which is fine for most systems...

I've been using the settings that I mentioned previously for some time now, and to date, have had positive results. I happen to be charging primarily, that is, close to 100%, by solar, and as such have a fluctuating current, with the rare exception of regulated, dc to dc charging as required. I'm thinking that the tail current range of 2%-4% is based, in part, on whether you are charging off shore power (~2%) or fluctuating solar (~4%) - just a guess on my part - and also the state of health of a battery over time (new battery vs older battery with sulfation degradation). You are probably okay with your 1% tail current on a relatively new battery (couple years old), but at 1% it may be on the narrow end of the acceptable spectrum and may take longer for the BWV to recognize a full charge - again, just my guess. I'm no battery chemistry engineer but I'm pretty sure that coming up with an exact percentage for the perfect tail current is a rather complex issue, but has some flexibility built in. I think the 4% value is sort of a one size fits all number - not necessarily the absolute ideal percentage but close enough to work well for most people. I'm simply using average values, within the range of what Battle Born and Victron recommend; 4% is Victron's default value and it has worked well for me. Afterall, they've engineered these beasts, their products work and, personally, I' have no reason to second guess them.

Rich

 

[buckland]

Just gotta ask.... what is "Tail current"?

 

[Wandering Sagebrush]

Just gotta ask.... what is "Tail current"?

I’m an old aircraft electrician, and I didn’t know either... Prof Google says:

The tail current is decaying current that represents open voltage and time dependent conductance elicited by the first step now closing when stepped to a hyperpolarizing voltage and vice versa if the step eliciting the tail is opening the channel.

 

[buckland]

Well … that that was as helpful as teat on a bull!! Ha! Just kidding … it did sound too above my pay grade so I dug up another from a battery forum. Quote:

"Tail current" is basically the current the bank will absorb at almost fully charged. It is used in the following situation.

As your batterys charges it "Absorbs" less and less current. The 702 will indicate 100% charge after looking at the following three conditions. Once all three conditions are met, the BMV will indicate the bank as 100% charged.

(Setting 2) Bank voltage at "Float Voltage" or higher
(Setting 3) Tail current at less than 4% (In my case 2.8%) of the total Ah rating of the bank
(Setting 4) For a set time of ?? Min. (In my case 30min)

 

[buckland]

Hey everybody... Just off the phone with BB. I outlined all I had in the camper with solar and controller and DC to DC charger and he recommended ..... relax.... select lithium preset and go camping. I asked about my install of the second battery in parallel and all he said to do was disconnect both ...put each a on tender to bring both up to same voltage.... then re-install in parallel. He said no need to tell the controller it is now 200 Amps. (I do not have a separate Battery monitor... just the Victron 100-20 w/bluetooth). The only reason for the second BB battery is we have two eBikes to charge through the Renogy 1000W inverter. Otherwise we would only need one.

 

[ri-f]

I’m an old aircraft electrician, and I didn’t know either... Prof Google says:

The tail current is decaying current that represents open voltage and time dependent conductance elicited by the first step now closing when stepped to a hyperpolarizing voltage and vice versa if the step eliciting the tail is opening the channel.

Nice try: ), but this definition refers to tail currents in medical-neuroscience applications. Rolls Batteries has an explanation closer to what we are talking about. Rolls is referring to their AGM batteries here, not Lithium, nonetheless, it's a pretty good simplistic explanation for Tail Current:

END AMPS OR RETURN AMPS

As batteries near full capacity, charge current decreases. End Amps, Return Amps or Tail Current refers to the lowest output of current (Amps) flowing to the batteries as they have reached full capacity. Some chargers will determine this set point has been reached by monitoring current output to the battery bank. If the charge current drops, reaching the End Amps/Return Amps/Tail Current set point before the programmed Absorption time has completed, this will trigger the charger to shut off or switch to the Float voltage phase which holds the battery bank at 100% SOC. The charger will complete the full programmed Absorption time if this set point is too low or programmed at 0%.

The recommended End Amps/Return Amps/Tail Current set point for Rolls Flooded models is 2% of the 20 Hr AH rating (C/20) of the battery bank. Typically, when current drops to the 2% set point for 1 hour the battery bank has reached 100% SOC.

Rolls Flooded models with Advanced NAM may have a slightly higher End Amps/Return Amps/Tail Current set point as the cells are less resistant to charge and current output will remain slightly higher at 100% SOC. (2% recommended, 2-5% range) An adjustment to this set point may be required when these models replace other Flooded batteries. Test specific gravity at Float Charge to confirm 100% SOC.

WARNING: The End Amps/Return Amps/Tail Current setting, combined with sulfated batter(ies), may confuse the charger as added resistance will reduce the flow of current. This may falsely trigger the charge to end the Absorption charge prior to reaching 100% SOC. Test specific gravity regularly to confirm the battery bank has reached 100% SOC and adjust this set point and/or Absorption time as necessary.

---------------------------------

The tail current percentage range can be anywhere between 0.5 (narrow end) to 10% (wide end). 4% being the typical default for LiFePo4 batteries. And 2% to 4% being common set points values.

Rich

 

[Wallowa]

So setting the Tail Current point protects the battery from overcharging [?] by shutting off the charger or going into float?

 

[ri-f]

So setting the Tail Current point protects the battery from overcharging [?] by shutting off the charger or going into float?
-----------------------------------------------------

Something like that. It won't shut off the charger, your BMS will shut it down if it exceeds > 14.7v on a BB. The tail will just reduce the higher absorption voltage so it doesn't keep putting in, for example: 14.4v endlessly and unnecessarily when a full charge has already been met. When the criteria for dropping to a float voltage are met (i.e., minimal current, for a set length of time) it will drop the voltage from absorption, towards the float set point, for example: ~ 13.2v if your on an AC charger, or at least less than absorption voltage, if you're on a fluctuating charger like your solar panels.Anyway, adjusting the tail current percentage correctly, somewhere between 0.5 to 10% (typically 2-4% on the average), helps to ensure that your SOC reading is synced up correctly and giving you an accurate meter reading, and that the charging routine isn't ending prematurely or running too long. Any battery electrical engineers out there to explain this more precisely?

Rich

 

[rando]

With a battery charger, the tail current is what tells the charger the battery is fully charged and to switch from absorb to float. This is not very important for LiFePO4 as unlike a lead acid battery, they don't really need much of any time in absorb. A lead acid will switch from bulk charge to absorb charge at about 80% SOC, and then take 3 - 6 hours in absorb to get to to 100% SOC, which is very important for lead acid. In contrast, an LiFePO4 will be at 95 - 99% SOC when you switch from bulk to absorb, so it will only take 15 - 30 minutes to get to 100% SOC, and it doesn't care if you don't make it all the way to 100%

For LiFePO4 you can set the tail current fairly low, like 1-2% of the battery capacity and then set the absorption time limit to 30 - 45 minutes. That way if you have loads on the battery when you charge, or varying current available from solar you won't fool the tail current detection and you will drop to float in 30-45 min no matter what.

Tail current is a little different on a battery monitor like the BMV-712. In that case it is used to detect when the battery is fully charged to resync the SOC to 100%. If the voltage is above the charge detect voltage AND the current into the battery is below the tail current, the BMV will assume the battery is full and reset the SOC to 100%.