Asking for some friends and family who are not yet on a full PV/backup/off-grid system, but getting sick and tired of replacing old 7Ah 12v batteries in UPSs, gate motors, alarms and garage motors.
Are the BlueNova LiFePO4 drop-in replacements, such as this one, any good?
What appliances would they be best suited for? E.g. a 2000VA UPS used for loadshedding to power a notebook & router, or a gatemotor opening and closing a couple of times during loadshedding?
Are there any caveats to them?
Has anybody here used them?
They are not drop in replacements for UPS batteries, they don’t have the required current capacity. The datasheet states 1.44A max continuous discharge current. That probably does not even carry the UPS with no load attached.
For something like an alarm they can probably work very well. For a gate motor, you would need to check the current requirements first.
But there is a caveat when using it as a drop-in replacement for an alarm. My alarm goes to ‘Storage Mode’ after a while and that drops the voltage just low enough that the internal BMS of the battery is not guaranteed to activate the balancer. I had to tweak it slightly to raise this voltage to the +13.8V required by the battery. Check the label on the battery, it states float voltage and that is really the absolute minimum charge voltage according to BlueNova.
Those work a battery quite hard. They don’t have a power supply capable of powering the motor on its own, so they always use the battery to cover the difference (which is why the gate fails the moment the battery goes, even though the power is on). But… they only do it for a peak of a few seconds. I would expect that a LiFePO4 should be able to handle that.
Also, garage door openers tend to have enough oomph in their power supplies to run even without a battery, so it’s good enough for that too.
But I agree on a UPS. Some of those things draw 2A just to stay alive…
The Sherlotronics chargers are slightly adjustable, so you can get the correct charging voltage out, and they work well for CCTV or as additional alarm batteries. In my case the alarm LA battery only power the alarm panel itself, all the sensors are powered from another Sherlotronics supply (common ground).
However, the disconnect voltage is not adjustable. Most LA things will disconnect around 10.x V, if they do at all, at which point any lithium replacement will be well and truly dead.
So I wouldn’t use it for anything that can feasibly “run down” such as a UPS. For an alarm and CCTV it should be fine.
During calibration (when you train it to find the stop-ends), it peaks at twice that. The Centurion control system has a current sensor built in (which is also how it detects collisions), and while running the calibration wizard it does show the current draw. Quite neat. I think the BlueNova battery should work just fine in this application.
I have a Blue Nova 8 Ah in a Centurion D5 for probably a year now and it’s doing just fine, I have friends running the same setup without any issues.
My dad uses a Blue Nova 22 Ah on his CPAP machine during load shedding, if I remember the machines 12V power supply is rated at 90 or 100W, but I never measured the actual current draw. He charges it with a 7A smart charger.
Personally if it lasts 2 years I would call it worth it, I have 2 rental units on our yard, so our communal gate does see a lot of opening and closings, and apart from loadshedding, where I live after we have a severe storm the power will almost certainly be off for 2 -12 hours, these conditions quickly kill those small 7Ah lead acid batteries, currently I replace one every 8 months.
Not to mention the hassle of first finding the gate motor keys or being stranded on the wrong side of the fence…