Log In | Register
Skip to main content
Topic: LFP batteries converter charging... (Read 243 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.
LFP batteries converter charging...
Although a good multi-stage converter NOT designed for LFP batteries WILL fully charge them, it may not do so when you expect it should. The problem is that when LFP batteries show a reading of, say 13.2V, they are NOT fully charged. However, a converter charger in 'float' mode expecting flooded-cell chemistry will see the battery as fully charged, and remain in float mode until the battery is nearly completely discharged. A battery monitor will reveal this issue when it may occur, and if the charger has a button to override and start bulk charge mode manually, this can skirt the problem. Because when shore power is connected or the generator is started the converter will start in bulk mode, this compatibility quirk may not show until you are staying awhile somewhere hooked up, especially in poor solar conditions...

Steve
2004 FL
2013 Honda Fit
Re: LFP batteries converter charging...
Reply #1 –
If someone has, as many of us do, a PD4645 upgraded from the original factory converter, they also have the boost button manual override that you allude to.

Note I'm talking about the older PD4645s, not newer versions have a lithium setting. 

You also have the option to use a jumper to essentially keep the boost button pressed all the time providing a constant 14.4V to the battery.   Progressive Dynamics states this is a way to use your older converter with Lithium batteries.

See page 3 - https://www.progressivedyn.com/wp-content/uploads/Support/manuals/Technical-library/PD4600-Jumper-settings.pdf

If anyone has tried this and has feedback, I would love to hear it.   I'm switching to a 100ah lithium soon and plan to do so without changing the converter (PD4645) or the isolator based alternator charging (following the logic that the factory wiring won't allow for overcharging) for now.  I also have a solar MPPT charge controller that is lithium compatible. 

Rich


2003 MB
Re: LFP batteries converter charging...
Reply #2 –
I see the same issue with our PD 9270 converter, I have to push the button on the Power Wizard to force it into full charge mode at times. It isn't a big problem since most of the charging needs are taken care of by the solar panels.
I have never disassembled the converter, it might be interesting to eliminate the Charge Wizard.

Larry 
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: LFP batteries converter charging...
Reply #3 –
It appears the PD solution simply removes the charge-wizard plug. This falls in line with using a single-stage charger for LFP, letting the battery BMS make charging decisions. However, this keeps the battery fully charged all the time on shore-power, not necessarily ideal for LFPs, as the battery life may be reduced. Unlike Pb based chemistry, Li batteries thrive at reduced levels of charge. If solar is sufficient to keep pace with overnight depletion on average, the converter may be powered on only as conditions require. Our CA camping rarely has hookups, so our converter stays off unless we need the generator to charge up.

One big advantage of LFP batteries is their highly efficient high-current charge/discharge profile, which makes powering a big inverter for occasional use of things like the microwave, hair dryer, portable heater, etc., much more sensible than with flooded-cells. Nice to be able to quickly re-heat your cup of coffee at 7am in a quiet campground, or run a portable heater for a few minutes when exiting the shower some frigid morning...

Steve
2004 FL
2013 Honda Fit
Re: LFP batteries converter charging...
Reply #5 –
A side note - the converter being switched on/off using the circuit breaker can eventually cause the breaker to fail - a 'switch' is not its intended function. I turn it off because when dry-camping turning on the whole-house inverter would cause the batteries to power the converter, which is trying to charge the batteries. This does not work. To minimize 'switching' I typically turn the converter on only when running the generator to charge the batteries.

Steve
2004 FL
2013 Honda Fit