LiFeP04 charge controller recommendations

trae

Adventurer
Again, the canned profiles from all makers are not conducive to longevity.

User-custom profile adjustability is what makes a good LFP charge source

not marketing materials touting "Lithium compatible"

volts are volts, amps are amps
Why would you need this flexibility? Other than maybe narrowing the discharge/charge limits?


Sent from my iPhone using Tapatalk
 

john61ct

Adventurer
The discharge LVC should definitely be adjustable, ideally per circuit, I want my refrigeration to keep going long after entertainment's been cut off, but before safety / comms/ navigation essentials.

But that has nothing to do with charging.

For longevity, at a given charge rate I want to terminate at 3.45Vpc

The only way to get that is a user-custom profile.

When I am occasionally checking SoH% via cap testing, or in the current cycling conditions I really want every mAh of capacity utilization, then I want to set the stop charge at the data sheet spec maximum, say 3.65Vpc

But doing that in normal cycling conditions would sacrifice a lot of lifetime cycles off the back end, maybe losing years of use.
 

CoExplorer

New member
What about using one of these?


From my research it seems Redarc is well respected, it has charge profiles for different battery chemistries, and also includes a built in MPPT so you can charge from solar or alternator depending on the situation. I have been eyeing this for my own build.
 

Rando

Explorer
What about using one of these?


From my research it seems Redarc is well respected, it has charge profiles for different battery chemistries, and also includes a built in MPPT so you can charge from solar or alternator depending on the situation. I have been eyeing this for my own build.
The Redarc is fine, but a little bit limited in terms of solar input and configuration. For about the same money you can get the Victron 30A DC-DC charger:

And the Victron MPPT Solar charger:

These are fully monitorable/configurable and have a wider range of inputs allowing for high voltage solar panels and simultaneous solar and DC-DC charging.
 

ducktapeguy

Adventurer
To update this thread,

I ended up getting a Victron MPPT controller, I think it was the 100/20 linked above. I also picked up a Renogy 30A DCDC charger. However, I'm having second thoughts and might switch over to the Renogy DCC30S or Kisae SCD1230 which are integrated charger/controllers. One problem is the stand alone DC charger are huge, relatively speaking. Maybe for a sprinter van or RV where they mount inside, it might not be an issue, but for under the hood of an SUV it takes up a lot of valuable space. It's about the same footprint as a small car battery at half the height, so finding a working spot for the charger and controller is getting complicated. I don't know why the DC DC chargers are so huge, I also picked up a 12/24V converter and tested it out like Swiftone recommended and it seems to work fine with the MPPT controller, and the combined size is less than the DC charger alone.

The other thing I don't like about the Renogy DC charger is the cooling fans. I must have overlooked that fans since I was looking at so many different controllers and chargers at once. But active cooling in the dirty and dusty environment under the hood of a car doesn't seem like a good idea. From the pictures is look like the Renogy and Kisae uses passive finned heatsinks without the fans.

The Victron controller is overkill for this particular purpose, I could have used a much cheaper 20A MPPT controller, but I have other plans for it in case I don't use it for this project. I do like the built in bluetooth monitoring from their app, I think that alone might be worth the added cost.

I looked at the RedArc unit also, but it's nearly double the price of other options so that kinda go eliminated quickly. I'm sure it's probably better than the less expensive options, but I have a very simple setup and don't really need all the bells and whistles. As long as my battery gets charged I'm satisfied.
 
Last edited:

john61ct

Adventurer
Electronics like this should **not** get mounted under the hood!

Unless specifically touted as designed for it,

and that aspect is one worth paying Aussie pricing for.

But IMO adjustable output is worth finding a spot in the rear.
 

pugslyyy

Expedition Vehicle Engineer Guy
What about using one of these?


From my research it seems Redarc is well respected, it has charge profiles for different battery chemistries, and also includes a built in MPPT so you can charge from solar or alternator depending on the situation. I have been eyeing this for my own build.
I have the REDARC BCDC1240D (the 40A version of what you posted) in my 4x4 van. It's not a full build out, just 200Ah of LiFePO4, solar panels, diesel heater, fridge, and removable bed platform.

I like that it seems to work.

I don't like that there is no configuration or ways to check the actual operation, status, etc., other than a few red LEDs on the front of it.
 

OllieChristopher

Active member
Electronics like this should **not** get mounted under the hood!

Unless specifically touted as designed for it
My Victron 75/15 is mounted under the hood with no issues whatsoever. I live in high temp weather and am banging around off road. The bluetooth feature is flawless as well. The IP 43/22 and 140 degree temp rating is more than sufficient for under hood use. While it not designed for it, there is no harm in using it as long as it's within the parameters of the units specs.
 

clydeps

Member
but an MPPT controller could potentially short the input side of the controller.
I can understand why someone might think that but it's never going to happen unless you were to use a truly humungous controller with a power rating exceeding the alternator rating.

To explain: MPPT controllers work by varying the impedance presented to the supply in order to find the sweet spot where the wattage (product of current and voltage) that the supply (i.e. solar panel) can deliver is maximised.

When the MPPT controller is being fed by a solar panel the input voltage and current will vary inversely and that sweet spot will be somewhere between maximum voltage and maximum current. If you feed it with an alternator though the input voltage is basically fixed so the "sweet spot" will be at the maximum current the controller can draw without exceeding its rated output current.

If you are charging a nominal 12V battery (at say 14V) with a controller rated for 20A the maximum power it can deliver is 280W, so the maximum input power will be about the same (maybe 5% higher due to losses in the controller.) So for a fixed 24V input the maximum input current would be 12A or thereabouts.

I used one of these in my slide-on - it automatically charges from either the alternator or my solar panels:

https://www.outbackequipment.com.au/thunder-dc-to-dc-20a-battery-charger
 

ducktapeguy

Adventurer
Another update on this.

After trying a few different configurations, I eventually settled on the Renogy DCC30S. I started out using the Victron MPPT + Boost converter as a DC/DC charger, but I noticed some strange behavior with it. At some times, measuring with the Victron app, it would be pulling the full 20A (rating of the boost coverter and controller) @24V, but only outputting a fraction of that power (~3A-5A) to the house battery. The rest of it must have been dissipated as heat by the controller. Not sure what was happening or why it was happening, but decided it wasn't worth troubleshooting and didn't want to risk burning my car down. I had ordered the standalone Renogy DC charger but returned it for the reasons I mentioned above.

Been happy with the DCC30S so far, there are some quirks and issues mainly with the app, but overall it's been working fine.
 

R_Lefebvre

Expedition Leader
Another update on this.

After trying a few different configurations, I eventually settled on the Renogy DCC30S. I started out using the Victron MPPT + Boost converter as a DC/DC charger, but I noticed some strange behavior with it. At some times, measuring with the Victron app, it would be pulling the full 20A (rating of the boost coverter and controller) @24V, but only outputting a fraction of that power (~3A-5A) to the house battery. The rest of it must have been dissipated as heat by the controller. Not sure what was happening or why it was happening, but decided it wasn't worth troubleshooting and didn't want to risk burning my car down. I had ordered the standalone Renogy DC charger but returned it for the reasons I mentioned above.

Been happy with the DCC30S so far, there are some quirks and issues mainly with the app, but overall it's been working fine.
I'd love to hear more about your experience with the Renogy. I have one as well, installed in a trailer off-grid system. I do not have the Bluetooth system yet, so I don't know what I'm missing.

Generally I'm happy with the system, but had one significant issue. I found it would favor the solar charging much too much, and not draw from the alternator, almost ever. I know that it is programmed to use the solar panels as much as possible. But I expected it would "top up" to the full 30A by drawing from the alternator. But it doesn't. There were times it would be getting 5A or less from the solar, and still not draw from the alternator. Did a lot of troubleshooting, but at the end of the trip, I learned to just unplug the solar if I wanted to be sure to draw from the alternator. The only time it would automatically take from the alternator, is basically full dark conditions.
 
Top