cpt-pat avatar image
cpt-pat asked

Blue Smart IP 67 charger: Sub-optimal behaviors charging lithium batteries

I was just about to buy a 25 A charger until I encountered these issues. Can anyone validate my concerns?

I am using the product HTML manual (for the 240 volt version - see item 6 below) and the VictronConnect app with the Demo Library to review configurations.

1) The charger won't interoperate with the Smart Battery Sense via bluetooth, so the terminal voltage can't be detected at the battery (also, for lead-acid bats, the battery temperature can't be detected at the battery, only at the charger location, which may and should be different).

2) There is no way to prevent a reabsorption cycle. It can't be set to run less frequently than every 45 days. Yes, I could set the absorption voltage to be the same as the float voltage, but that defeats the purpose of absorption at a higher voltage. This is bad treatment of LiFePO4 batteries that don't need periodic reabsorption.

3) The chargers don't interoperate with the Smart Shunt, causing the same issues as item 1 above, while also making it impossible for the charger to actually detect the battery charge current in the presence of static loads on the bus.

4) If I draw a high current from the bank for more than 4 seconds, the charger reverts to a full absorption cycle and the behavior can't be overridden. My SSB transmitter draws 50 amps when I transmit. I don't want a reabsorption cycle to be triggered every time I use it. This would also be maltreatment of LiFePO4 batteries.

From the manual:

"Note that even when the re-bulk setting is disabled, re-bulk will still occur if the charge current is maintained at the maximum charge current for 4 seconds."

5) There is no clear definition in the documentation of when the charger switches from float to storage mode.

6) There is no HTML manual on line for the 120 volt AC product. I've already discovered with other products that the PDF manuals omit some details.

7) There is no way to disable charging at and below zero degrees C. There's only a documented warning not to do that with LiFePO4 batteries. And where would that temperature be detected, at the warm charger? This issue alone precludes using the charger. Everyone doesn't have a BMS that disables charging below freezing.

8) When using the "Li-ion" factory preset, voltage temperature compensation is not disabled. Instead, it is set at -16.20mV/degree C. This is a serious error. LiFePO4 batteries do not require charging voltage temperature compensation. This problem, combined with item 7 above, could cause serious permanent damage to LiFePO4 batteries. At zero degrees C, charging at the factory preset 14.40 volt absorption voltage, instead of being shut down entirely, will be 14.81 volts (and higher at lower temperatures).

9) There is no way to see, set or, as cautioned in the setup under Absorption Duration: "disable the tail current."

Did I get anything wrong there?

Lithium Batterycharger
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2 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

What is your planed setup that you are always or for very long periods of time connected to the grid?

But I have to agree that Smartnetwork compatibility for the BlurSmart chargers would be great. If you need that feature you have to use the Phoenix Smart charger.

6. Why should there be a separate manual for the 120V version? The only difference is the AC input voltage.

7. The BMS should stop charging if the temperature is to low. If it doesn't do it you should not use it if you expect temperatures below 5°C.

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cpt-pat avatar image
cpt-pat answered ·

< What is your planed setup that you are always or for very long periods of time connected to the grid?

My sailboat sits on shore power for months at a time in the winter, while I am 7,000 miles away.

Leaving a substantial investment in lithium batteries off a charger for that length of time, and provisioning an alternate power source for some low power systems that must remain energized, just isn't practical.

It appears to me that only the Phoenix chargers may be suitable even though it too would hammer my batteries with an unwanted absorption charge every 45 days maximum. There is no way that I would use the Blue Smart charger with any lithium battery. It appears the word "lithium" was just slapped onto the Blue Smart charger without proper engineering consideration, and that lowers my confidence in Good Engineering Practices of the entire line. Sadly, Marketing often trumps Engineering, and when I see evidence of that, I steer clear.

Phoenix Smart Charger setup caution: For LiFePO4 batteries, do not use the built-in preset labelled "Li-ion." Doing so, without modifying the settings in Expert mode, will result in temperature compensation remaining active, and the low temperature cut-off being disabled. The preset float voltage (13.80volts) is also too high for LiFePO4 batteries. Instead, use "Select preset" and choose "Lithium Iron Phosphate (LiFePO4)" from the drop-down menu, which will give you reasonable settings for LiFePO4 batteries. I can see where this could cause mis-selection by users who don't understand the distinction between Li-ion and LIFePO4 batteries.

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