LiFePO4 overload. Need to digest this for a while. Great thread.
Has this comparison article ever been posted? I didn't find it on the Battle Born site.We are in the process of testing some DC to DC converters up to 30 amps on our alternator test bench.
We will be testing the CTEK d250s next week too. I received an email from the author of this post, asking us to join the thread.
The review of this charger and the DC to DC converters results will be posted soon, we will link them for you.
I bought a CTEK D250S & SmartPass combo a few years ago when I was thinking lead-acid, but I've come around to an LFP battery. I'd like to know if the CTEK combo is a good fit, or if using it would be inappropriate with an LFP battery.I've been using them for years, any specific Qs?
It looks to me that some LFP manufacturers are trying to gain wider adoption by promoting the "drop-in" aspect of their batteries, even if existing LA charging systems really aren't a good fit with LFP chemistry. I can understand doing that, but I'd rather do a proper installation once, even if that means selling the CTEK gear at a loss to someone wanting it for LA charging.Absorption voltage for the CTEK is 14.4V, Float at 13.8V.
IMO way too high for LFP, but many think OK.
The current rate in DCDC mode is limited to 20A, often too slow.
Smartpass is just a bypass, up to 80A but voltage following, profile depends on upstream source.
LVD cutoff is 11.5V, way too low IMO.
But up to you, won't cause drastic "damage", very robust build quality, dependable. The MPPT component is meh.
Many think I am too perfectionist wrt LFP care, maximizing longevity.
Thanks for the information. Time to get mine sold.
Either that, or part of a fully integrated system from a single manufacturer, including the battery. It'd be nice to see manufacturers develop a universal interface so the battery could tell another brand of charger what it wanted, but such commonality is rarely accomplished.IMO all charge sources for LFP should be fully user-custom adjustable.
I have yet to see one actually marketed as for LFP that I would buy.
@battlebornliion I found this page on your site https://battlebornbatteries.com/charger-compatibility-table/Hi everyone!
Here is some info that is not in the marketing materials. The BMS is not bucking or doing any voltage regulation. It is simply monitoring the voltages, current and temperatures and acting as a high current switch, when things are out of whack. Charging and discharging circuits may be opened independently. For each, we have a bunch of high-current MOSFETs (along with some snubber circuitry) doing the switching. Basically, the charging switches will open if one of the following is detected: one cell exceeds a prescribed high voltage, the cell temperatures exceed 140F, the MOSFET temperatures exceed 170F, the charging current exceeds 200A for 0.5s, or 100A for 30 seconds. The discharging switches open if one cell falls below a low voltage threshold, the cell temperatures exceed 140F, the MOSFET temperatures exceed 170F, the cell temperatures fall below 25F (deadband at 30F), the discharging current exceeds 200A for 0.5s, or 100A for 30 seconds. High current disconnects are automatically reconnected after 5 seconds. Note that discharging is still allowed under low temp and high voltage, and charging is still allowed under low voltage. The 0.5s high current allows for initial cranking currents which typically last a couple hundred milliseconds. It's our happy medium between allowing cranking and protecting against short circuit. The BMS also has a standard passive balancing mechanism, whereby cells that are charged faster than the rest bleed current through a resistor. The batteries can be connected in parallel (provided you use appropriate cables and fittings to handle the current), and in series up to 48V.
Operationally, the batteries should be bulk charged up to 14.3-14.6V, and absorb ideally at 14.4V. The person who suggested that Li-ion batteries should not float is correct. However, some chargers require a float, and we recommend setting it at 13.6V or below, since that is below the natural float of the charged cells. The cells leak charge at a rate of only 2-3% per month, so they can be stored for long periods of time without a trickle charge.
That's it in a nutshell. We would be happy to answer any other questions. Feel free to call: 855-292-2831