question

cpt-pat avatar image
cpt-pat asked

Has anyone found how to disable "Repeated absorption" with Blue Smart IP22 12 | 30 chargers with Lithium batteries?

I have Battle Born LiFePO4 batteries. They do not require repeated absorption. In fact, unnecessary absorption it is detrimental to all LiFePO4 batteries. Reabsorption is a lead-acid battery requirement to prevent sulfation.

I tried setting repeated absorption to "0" days, and the setting reverted to "1" day. Then I tried "999" days and found the setting reverts to "45" days. Victron forces 45 days as the maximum setting. I could set the absorption voltage to some low value, but then I would have to reconfigure the charger every time I actually wanted to charge to a higher SOC.

Repeated absorption should be set to "disabled" in the "Li-ion" factory profile (caveat: that factory profile is set at 7 days!). This looks to me to be a software oversight.

Suggestion to other users: to prevent these chargers from cooking your lithium batteries, set the tail current (disabled in the profile) to 7.5 amps (the maximum) so the charger at least diminishes the overcharging damage by terminating charging quickly (provided there are no parasite loads) of an already-fully-charged battery.

battery chargingLithium Battery
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8 Answers
pmikep avatar image
pmikep answered ·

If you are requesting that the Setting: "Disable" be added for the Repreat Absorption, then +1. (I don't recall seeing this on my SmartSolar MPPT. But it IS in my Multiplus, and I wish that I could disable it.)

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cpt-pat avatar image cpt-pat commented ·
Yes, having a "disable" option would resolve the issue. But I'm not sure Victron is listening. I've found other posts making the same request.
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baxter avatar image
baxter answered ·

+1 for this Feature. Disable repeated absorption for LFP. It is a lead acid thing and not usefull for Lithium at all.

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ipet avatar image
ipet answered ·

+1 for this Feature

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cpt-pat avatar image
cpt-pat answered ·

Going on a year now. Still no response from Victron on this issue...

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cpt-pat avatar image
cpt-pat answered ·

why.png

Why is the switch there in the configuration, but it is greyed out?


why.png (62.1 KiB)
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scubadoo avatar image
scubadoo answered ·

An old thread I know.

I also have a Victron IP22 30A battery charger and although it is only used occasionally with solar and alternator being the primary charge sources for our in use daily now 8 year old 4 cell 300Ah Sinopoly LiFePO4 battery.

My default settings are absorption 14.10V for the minimum time then "float" at 13.40V. The battery is always at 100% SOC at this point according to both the Victron SmartShunt and the Junctek battery monitors.

What possible damage or longevity effect could an absorption cycle to say 14.20V once every 45 days possibly have? Absolutely zero in my books. We are not discussing "recondition" mode here.

14.10V is attained most days here from either solar or alternator charging with no significant capacity loss so far.

If we ever settle down long term the charger would no doubt be set to power supply mode at perhaps 13.4V. No "absorption" mode then anyway.


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johanndo avatar image
johanndo answered ·

What is the point of disabling repeated absorption when your battery runs daily into bulk / absorption any way when the sun rises? Set it to 35 days if it bugs you or disconnect the battery.

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cpt-pat avatar image
cpt-pat answered ·

Yes, this is an old thread. I'm still waiting for an answer as to why Victron provided a switch to disable repeated absorption -- and then disabled the switch. This seems like an software development error.

I just want the charger to function as designed and not be forced to accept an artificially disabled feature.

Lead-acid batteries need to be recycled to prevent sulfation. Repeated reabsorption charging of lithium batteries is unnecessary abuse and could cause memory-effect degradation.

LiFePO4 batteries undergo accelerated age degradation when they are maintained at a 100% SOC. Ideally, they should be stored at or below a 50% SOC, and charged to a higher SOC only just prior to use. In my case, just prior to disembarking on a voyage. Mine is not a solar installation where aging caused by continual daily cycling is unavoidable.

My batteries are set to float at 13.2 volts (~50% SOC) and I want the voltage to stay at that value without repeated recharges. I do however want to retain that 50% SOC reserve capacity in case there is a failure of shore power because I have essential systems running on board, and "power supply" mode won't accomplish that recharge cycle after a mains supply power failure.

Please Victron, just enable the switch in a software update, and let the consumer decide when to use it. Set the factory default to "on" for lead-acid battery profiles, "off" for lithium battery profiles, and let the user decide for custom profiles.

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