diy solar

diy solar

Struggling with basic LiFePO4 settings in Epever Tracer

Epever is just one option
I am looking for the highest performing low cost controller that has a remote panel read-out (not bluetooth only because I don't want to find my phone and start up an app when I can just glance at the meter and since I look at the SOC so often). I want it to provide a quality charge via my JBD BMS to the 4 likely recycled 280aH cells I found at a bargain off Ali and suggested as a viable solution for the low-end guy (me) by the owner of this blog.

I guess I got confused here because I though that the Xtra line of EPEVER controllers has something regarding lithium charging that e.g. the Tracer line was missing???

(Here's some brief notes on my logic thus far ....
My criteria was as follows when I started 7 months ago,
- portable (for use on the road in the camper)
- more cycling storage than my lead/acid (dual GC2 batteries 230aH published/115aH usable)
- affordable cells (the Ali cheap Chinese 4s 280aH qualified)
- affordable support system (the cheap Epever SCC and JBD BMS qualified)
- low end system (no portable wiring closets, no sacrificing of my 250 sq ft living space to 20-50% full of electronics)
- no B2B (wanted to be able to jump my engine using the existing 200A bridge relay back to chassis battery)
- no B2B (wanted to take full advantage of 150A alternator without compromising back down to 30A with a B2B and with investing $$$)
- no 24/48V systems (wanted to use existing 12V architecture without additional point of failure with a large buck converter)
- no 24x7 inverter-use needed (wanted to use existing 12VDC architecture and periodically coffee/microwave is only inverter use)
- remote panel meter as primary indicator (didn't want to fire up bluetooth everytime for SOC - I look at it too often)

Now Victron doesn't offer any or "offers minimal" of these and I'll leave it to those with the cash and room to play. My opinion of them is not great after that 500RPM alternator burn-out trick they used to sell their products (most alternators turn around 1500 RPM and are better designed than that lab rat)

At this point the fun part is starting to fade and I just want to get back on the road. I've basically have all the equipment installed now if I can just figure out how to configure it properly. I thought what was being said here is that the Epever Xtra controllers had something that was more easily configurable to work with these three, the 280aH cells, the JDB BMS and Epever. If anyone can help, I'd appreciate it. Starting to even consider taking all this out and just making room for 150 more lbs. using 4 GC2s instead of the dual GC2s I had before that were starting to hit the critical low SOC each day. I guess my main mistake was thinking that more had comped together a good working system out of this component-set. I'm already starting to see that my unchanged daily consumption of energy routine is taking a full day to recharge when compared to the old dual GC2 which was topped back up to 100% by noon each day. It's currently taking all day to get me topped back up and that doesn't seem like a good thing.

P.S. I now see that the 12V "drop ins" would have been a much better solution and even at $1000US + each, if you include time and all the later issues that come up, even though this is a price point well beyond what most camper owners are hoping to pay, in the long run there is not a lot of money saved when you count all the time that this setup requires to implement.
 
I am looking for the highest performing low cost controller that has a remote panel read-out (not bluetooth only because I don't want to find my phone and start up an app when I can just glance at the meter and since I look at the SOC so often). I want it to provide a quality charge via my JBD BMS to the 4 likely recycled 280aH cells I found at a bargain off Ali and suggested as a viable solution for the low-end guy (me) by the owner of this blog.

I'm confused - you have or have not purchased a charge controller? The MT50 remote display for EPEver does this. And you can set charging parameters with that display, but it is MUCH easier to modify the control parameters in the app and upload them to the controller.
Not sure what you mean by 'charge via' a BMS.
Owner of what blog? A viable solution for what exactly?
What does 'likely recycled' mean?

I guess I got confused here because I though that the Xtra line of EPEVER controllers has something regarding lithium charging that e.g. the Tracer line was missing???

All Tracer controllers can have 'user' parameters set to work with lifepo batteries.

(Here's some brief notes on my logic thus far ....
My criteria was as follows when I started 7 months ago,
- portable (for use on the road in the camper)
- more cycling storage than my lead/acid (dual GC2 batteries 230aH published/115aH usable)
- affordable cells (the Ali cheap Chinese 4s 280aH qualified)
- affordable support system (the cheap Epever SCC and JBD BMS qualified)
- low end system (no portable wiring closets, no sacrificing of my 250 sq ft living space to 20-50% full of electronics)
- no B2B (wanted to be able to jump my engine using the existing 200A bridge relay back to chassis battery)
- no B2B (wanted to take full advantage of 150A alternator without compromising back down to 30A with a B2B and with investing $$$)

- no 24/48V systems (wanted to use existing 12V architecture without additional point of failure with a large buck converter)
- no 24x7 inverter-use needed (wanted to use existing 12VDC architecture and periodically coffee/microwave is only inverter use)
- remote panel meter as primary indicator (didn't want to fire up bluetooth everytime for SOC - I look at it too often)

- Not sure what 'B2B' is, perhaps battery to battery?
- Lifepo4 is not recommended for starting an engine - too much current draw.
- Lifeopo4 is also not recommended for charging directly with an alternator. The internal resistance is so low in these cells that they will draw everything your alternator can put out - so at idle there isn't sufficient cooling and cooking it is common.
- You said 'no inverter use' then said you use an inverter for a microwave and coffee maker - both of which are very high amp draw and require a large inverter with very heavy cabling to support the resultant 12V loads from the inverter.
- Some kind of smart meter is recommended instead of relying on a solar charge controller for voltage or SOC. There are several on the market that utilize a smart shunt and are inexpensive and easy to hook up and configure.

Now Victron doesn't offer any or "offers minimal" of these and I'll leave it to those with the cash and room to play. My opinion of them is not great after that 500RPM alternator burn-out trick they used to sell their products (most alternators turn around 1500 RPM and are better designed than that lab rat)

Victron offers minimimal of what exactly?
Victron has a substantial line of solar charge controllers in various capacities and voltage ratings, DC-to-DC chargers and converters, meters and connectors. Yes, they are more costly. They are also very reliable and have excellent display and communication protocols.

At this point the fun part is starting to fade and I just want to get back on the road. I've basically have all the equipment installed now if I can just figure out how to configure it properly. I thought what was being said here is that the Epever Xtra controllers had something that was more easily configurable to work with these three, the 280aH cells, the JDB BMS and Epever. If anyone can help, I'd appreciate it.

These DIY systems can be very complicated. I've spent a couple of thousand upgrading my entire system for charging and batteries, and building a DIY lifepo4 battery pack from prismatic cells. There is a substantial learning curve, and much of the technology was simply new and foreign to me.
EPEVer Xtra is simply their newest version of their Tracer line - it uses the same control parameters, setup, and displays as the other Tracer models.
All of these components are easily configurable once you understand how to do it and what needs to be done to get what you want out of them. There is plenty of help here, but no one is going to arrive on a service call and set it up for you.
I recommend you start a thread on YOUR specific project and ask for help on specific problems you're trying to address.

Starting to even consider taking all this out and just making room for 150 more lbs. using 4 GC2s instead of the dual GC2s I had before that were starting to hit the critical low SOC each day. I guess my main mistake was thinking that more had comped together a good working system out of this component-set. I'm already starting to see that my unchanged daily consumption of energy routine is taking a full day to recharge when compared to the old dual GC2 which was topped back up to 100% by noon each day. It's currently taking all day to get me topped back up and that doesn't seem like a good thing.

None of us here can make this decision for you.
I will say that if you use hundreds of amp hours you will need a way to put them back. Larger solar panels, alternate charging methods and appliances, etc.
Yes, many here have 'comped together' as you call it, a working system. Everyone started from the same place.

P.S. I now see that the 12V "drop ins" would have been a much better solution and even at $1000US + each, if you include time and all the later issues that come up, even though this is a price point well beyond what most camper owners are hoping to pay, in the long run there is not a lot of money saved when you count all the time that this setup requires to implement.

'Drop ins' have the same challenges as a built battery from cells.
Yes, the DIY method does save a LOT of money. Battleborn batteries are still $800 each for 100Ah batteries. They are not 'drop in'. People will do that, but reliability and longevity can surely suffer.

Let me know if you want the charging parameters I use for mine, as you requested in my profile post. I can post them here, PM them to you, or post them in a new thread for your project.
 
As an aside, I would not purchase any of my components from either Alibaba or AliExpress. Too iffy and unreliable, and you don't really know what exactly you're getting. I only source from reliable US entities. This isn't an anti-china-made policy I have, but of sourcing, for product support and for warranty/return options. JMHO.
 
Thanks for the detailed response. And the main urgency I am working within is the time window for returned merchandise. Do you believe that the Xtra line is worth using over the Tracer AN line at the moment is my primary request for clarification.

Regarding starting my own thread, is this one discussing 4 primatic LFP cells, JBD BMS and Epever. My apologies if I hijacked someone so I'll start a new one after this.

Yes, regarding your profile I would love to see what you use for both driving and for camping (I assume????) I will add what I have plagiarized here (LOL) and you can comment if I am on the right track. It doesn't matter though because I really like your idea of multiple profiles.

Otherwise tidbits ....

Regarding Victron, they lost my respect with the "dummied up" 500RPM alternator burn out routine on youtube. Their equipment is way beyond my price range and their using bluetooth as the only interface to their controllers is a show stopper for me because I like the small MT50-style display I can walk by and quickly see the flashing solar "live" light with an amp indication into the battery. True a shunt monitor also shows if a charge is taking place and these are the 2 gauges that I't like to mount as this is what I have been living with using the lead/acid setup, both the shunt monitor and a charge controller monitor. I already have the shunt coulomb counter based monitor and I want to also mount the controller monitor. So that is why Victron doesn't meet my needs, there's no wall-mount meter and their solutions are too high-tech, bulky and out of my price range.

Regarding alternator charging, my somewhat unique situation seems excellent for direct alternator charging. The stock vehicle came with a 150A alternator and a AGM lead/acid for chassis starting, engine computer, lamps etc. The dash electronics and headlamps provide a 30-45A constant load. The rest of the 150A is up for grabs The motorhome factory wiring sends a "engine running" signal to a 200A solenoid that conducts to bridge the positive battery terminals from the chassis battery post via a 2/0 cable for a total distance of about 15' to the "leisure/house" battery. The voltage measured at the alternator is typically 14.2 in a lead/acid environment and you are correct that the internal resistance of the LiFePo4s does pull the alternator voltage to 13.8V but apparently the resistance of that 2/0 15' run is enough to keep the alternator from going up in flames. I have both a hall effect amp meter and temperature probe on the alternator diode array and even at an idling speed of around 700 for the diesel, the pulley up-spin has the alternator rotating at least twice that fast. The load of a 4s280aH bank managed by a JBD BMS has only about a 55A draw on the system at a 35% SOC and watching the idling alternator over a period of about an hour, the maximum temperature read across the diode block climbs up to about 80C at idling speeds. For an increase to about 1200RPM (2400 equivalent alternator RPM) will cool the diodes down to about 60C while only increasing output to about 60A total. Additionally the jumping or boosting needed is very infrequent and in most cases the lead/acid still has a slight bit of charge that can be envigorated if it is bridged, where the lead/acid becomes sort of a large capacitor to keep the amp draw from skyrocketting in the emergency situation where one would have to emulate a jump-off from the lithium "leisure/house" battery pack to start the engine.

Here is my profile that I stole from all the knowledgeable folks here. Thanks to all but as usual NO CREDIT to anyone for my theft ;-)

Code:
BatType: 0
BatCap: 280
TempComp: -3
OVCutOff: 14.60
ChargLmt: 14.40
OVRcv: 14.50
EquilV: 14.10
RaisV: 14.10
FloCharg: 13.60
RaisRcv: 13.20
LVRcv: 12.80
WarnRcv: 12.80
LVWarn: 12.00
LVCutOff: 11.50
DischaLmt: 11.40
RatedLv: 0
EquilDur: 0
RaisDur: 120
BatDisch: 30
BatCharg: 100
ChargMode: 0

Thanks for all the good info, but the way!!!!!!!!!!
 
Thanks for the detailed response. And the main urgency I am working within is the time window for returned merchandise. Do you believe that the Xtra line is worth using over the Tracer AN line at the moment is my primary request for clarification.

No. Setup what you have, which is which model exactly?
Do you have a RS485 cable and a PC or laptop? I'm assuming so.

Regarding starting my own thread, is this one discussing 4 primatic LFP cells, JBD BMS and Epever. My apologies if I hijacked someone so I'll start a new one after this.

Asking or answering associated questions to an existing thread is fine, but I think this is beyond that.

Yes, regarding your profile I would love to see what you use for both driving and for camping (I assume????) I will add what I have plagiarized here (LOL) and you can comment if I am on the right track. It doesn't matter though because I really like your idea of multiple profiles.

I'll post them next.
I don't need or want my battery pack sitting at 100% SOC parked in the driveway for weeks or months. And in so-Cal it can get warm, so wouldn't be surprised to see the temp sensor at 95 or 100 degrees over summer. It makes no sense to try to run some kind of air conditioning in a stored motorhome. The pack can survive just fine at 70% with no load. Everything can be turned off or disconnected, including the battery itself.

Otherwise tidbits ....

Regarding Victron, they lost my respect with the "dummied up" 500RPM alternator burn out routine on youtube. Their equipment is way beyond my price range and their using bluetooth as the only interface to their controllers is a show stopper for me because I like the small MT50-style display I can walk by and quickly see the flashing solar "live" light with an amp indication into the battery. True a shunt monitor also shows if a charge is taking place and these are the 2 gauges that I't like to mount as this is what I have been living with using the lead/acid setup, both the shunt monitor and a charge controller monitor. I already have the shunt coulomb counter based monitor and I want to also mount the controller monitor. So that is why Victron doesn't meet my needs, there's no wall-mount meter and their solutions are too high-tech, bulky and out of my price range.

I have a Victron Orion dc to dc charger, the smart 12/12-18. It's a wonderful piece of equipment. I wanted something for after a boondocking stint over cloudy days, or at night, with a low battery, while driving, to at least put some amps back in the battery pack. I have it on a low boost and float level to just bring the pack up to about 95%.
Regarding alternator charging, my somewhat unique situation seems excellent for direct alternator charging. The stock vehicle came with a 150A alternator and a AGM lead/acid for chassis starting, engine computer, lamps etc. The dash electronics and headlamps provide a 30-45A constant load. The rest of the 150A is up for grabs The motorhome factory wiring sends a "engine running" signal to a 200A solenoid that conducts to bridge the positive battery terminals from the chassis battery post via a 2/0 cable for a total distance of about 15' to the "leisure/house" battery. The voltage measured at the alternator is typically 14.2 in a lead/acid environment and you are correct that the internal resistance of the LiFePo4s does pull the alternator voltage to 13.8V but apparently the resistance of that 2/0 15' run is enough to keep the alternator from going up in flames. I have both a hall effect amp meter and temperature probe on the alternator diode array and even at an idling speed of around 700 for the diesel, the pulley up-spin has the alternator rotating at least twice that fast. The load of a 4s280aH bank managed by a JBD BMS has only about a 55A draw on the system at a 35% SOC and watching the idling alternator over a period of about an hour, the maximum temperature read across the diode block climbs up to about 80C at idling speeds. For an increase to about 1200RPM (2400 equivalent alternator RPM) will cool the diodes down to about 60C while only increasing output to about 60A total. Additionally the jumping or boosting needed is very infrequent and in most cases the lead/acid still has a slight bit of charge that can be envigorated if it is bridged, where the lead/acid becomes sort of a large capacitor to keep the amp draw from skyrocketting in the emergency situation where one would have to emulate a jump-off from the lithium "leisure/house" battery pack to start the engine.

This is not recommended. Winnebago installs the same kind of isolator/combiner solenoid that joins the house and chassis batteries when the key is on. It's a great way to fry something. I removed it. Instead I have a Victron Orion that turns on and charges the house battery when the key is on with a maximum draw of about 25A, supplying up to 18A to the house battery. Safe, configurable, and easy to even turn off if desired.

Here is my profile that I stole from all the knowledgeable folks here. Thanks to all but as usual NO CREDIT to anyone for my theft ;-)

Code:
BatType: 0
BatCap: 280
TempComp: -3
OVCutOff: 14.60
ChargLmt: 14.40
OVRcv: 14.50
EquilV: 14.10
RaisV: 14.10
FloCharg: 13.60
RaisRcv: 13.20
LVRcv: 12.80
WarnRcv: 12.80
LVWarn: 12.00
LVCutOff: 11.50
DischaLmt: 11.40
RatedLv: 0
EquilDur: 0
RaisDur: 120
BatDisch: 30
BatCharg: 100
ChargMode: 0

Thanks for all the good info, but the way!!!!!!!!!!

What did you set for boost and equalize duration? Looks like equalize duration is zero - good. 'RaisDur' must be boost duration - you likely don't need two hours - I would start with 20-30 minutes and see how your pack does boosting at 14.1V. If no cells hit bms cutoff then you're golden. RaisV must be boost voltage - 14.1 is a good start. I find that the controller will tend to read the charge current on top of the actual battery current and show a considerably higher voltage, and will switch too early to float. This is where you have to play with the voltage and duration to get your charge level to where you want to be.
Parameters look fine otherwise.
Float appears to be 13.6V - fine for servicing loads.
Boost reconnect? If it's higher it will boost sooner, lower will let the battery float lower 'till it switches to full charging mode/boost.

Were you able to configure your control parameters and get them to load into your controller? Some of the values can be fussy - the program won't let you load wonky values. For example, boost duration has a minimum of 10 minutes I believe.

Also, if the controller is already in boost and you adjust the duration, the new value doesn't take affect until the next boost session. You can load the value and power-cycle the controller - it will come back on with the new boost duration.

Boost duration does not start its countdown UNTIL the battery reaches boost voltage. If it never gets there for loads present, the controller will stay in boost.

Same for float - if the battery never gets down to the re-boost voltage it won't reboost.

Adjust these parameters until you get what you want out of it. I've played with mine for hours, testing and adjusting, watching the bms app, the controller app, and the charge meter app. I'll put the controller on a tablet and the bms on a smartphone, switch back and forth with the coulomb meter.
 
Last edited:
These are the control parameters I've arrived at with much experimentation. Although I've still not used them in a daily living situation, so some further adjustment may be necessary. I also did quite a bit of top balancing at the high knee with a resistive load (headlamp bulb) on the high cells that were balancing. Overkill bms only cuts back charging by a half an amp or so on the balancing cell. By the time the pack gets that high of charge state current has tapered off to under 5A. They balance very well now all the way to about 3.55-3.6Vpc. If I try to charge to the full 3.65Vpc one will always go over and bms shuts off charging altogether till it settles back to 3.5Vpc.

For long term storage when we're not using the coach:



For active daily use:

 
Steps to update controller:
1. Start monitoring the controller to confirm you're connected and communicating.
2. When updating for lifepo you want to start the program menu for PARAMETERS(P) Control Parameter(For LiBattery controller product) option. Shown in the image below. This is important.
3. Now with the control parameters settings window open, READ your controller to download the existing settings.
4. Import your desired profile, or modify the ones you just read from your controller.
5. Update controller.
6. Read to verify settings changes.
7. Export settings to save them for future updating or resetting.

 
Last edited:
I can't thank you enough. I have less than 30 days on my two Tracers so I just ordered the Xtra to replace. Note that none of the generation controllers I first purchased this month have the LiBattery option when connected to the laptop, so that will be new to work with. I am with you in not wanting to cook. My winter usage is normally about a 100aH overnight depletion and it takes quite a few hours to get the bank recharged, even on cloudless days so while I am wondering how the boost time window fits into all this, my first thought is that I always want mine in boost since recharging is a near all day afair at the 22A or so out of my multiple panels. (100aH for heater fan in winter and 100aH for many house fans in summer peak is about the same) In am in mine full time with various times away that I will do as you say, reduce to 50% and park. Thanks again!
 
The Xtra has the li-battery control parameters, a nicer case/box, a finish cover over the wire terminals, a nicer display, and more button display controls. Kind of moot with and MT50, but there ya go. Since I was putting mine on the wall I wanted the nicer unit - it was like $20 or $30 more. And the latest and greatest of everything. I've been happy with them both.

I found out subsequently that you cannot set lifepo charge parameters without the RS485 cable, so ordered one of those and had to learn the whole process the hard way. ?

 
So now that we've COMPLETELY hijacked this thread...here's my lifepo pack with converter/charger and inverter, and the old battery well the GC2's came out of that now houses the dual Group24 starting batteries with their own 100W PV and 10A controller, and orion dc to dc charger.
We seem to use about 100-120Ah overnight as well, especially if the LPG ducted air furnace runs much. I that thing was about 8A, it's more like 12A when it's running.





2005 Itasca (winnebago) Sunrise 31W. We bought it new in November of 2004:






 
Last edited:
These are the control parameters I've arrived at with much experimentation. Although I've still not used them in a daily living situation, so some further adjustment may be necessary. I also did quite a bit of top balancing at the high knee with a resistive load (headlamp bulb) on the high cells that were balancing. Overkill bms only cuts back charging by a half an amp or so on the balancing cell. By the time the pack gets that high of charge state current has tapered off to under 5A. They balance very well now all the way to about 3.55-3.6Vpc. If I try to charge to the full 3.65Vpc one will always go over and bms shuts off charging altogether till it settles back to 3.5Vpc.

For long term storage when we're not using the coach:



For active daily use:

Noticed on the "Long term storage" settings you have 230AH rather than the 200AH in your regular settings.... was that a misprint or is there a reasoning for the different values?
 
Hey Guys,


Just got this same Epever unit and experienced the same instability as OP. Turns out you should not set the charging limit voltage equal to the boost voltage even though the software allows it. There needs to be some voltage margin to prevent the controller from bouncing between boost and cutoff. 50mV seems almost adequate so I went with 100mV to be safe.


To state it another way if you set boost voltage to 14.4V and charge limit to 14.4V, when the controller tries to boost to 14.4V it will actually wiggle around this point from say 14.35 to 14.45. This will inevitably trip the charge limit voltage and cause the controller to disconnect the panel after which the process repeats again as shown in OP's graph. Simply lowering the Boost voltage or raising the charging limit voltage to allow for the wiggle provides constant charging without all the instability. Personally I just raised the charge limit voltage 100mV since I have a BMS to cutoff the pack anyways, I set the boost voltage as desired and now there are no issues.


The blame here can probably still be placed on Epever because if they are going to enforce any rules then they should also enforce these gaps between limits that conflict due to voltage/regulation noise.
 
Last edited:
Hey Guys,


Just got this same Epever unit and experienced the same instability as OP. Turns out you should not set the charging limit voltage equal to the boost voltage even though the software allows it. There needs to be some voltage margin to prevent the controller from bouncing between boost and cutoff. 50mV seems almost adequate so I went with 100mV to be safe.


To state it another way if you set boost voltage to 14.4V and charge limit to 14.4V, when the controller tries to boost to 14.4V it will actually wiggle around this point from say 14.35 to 14.45. This will inevitably trip the charge limit voltage and cause the controller to disconnect the panel after which the process repeats again as shown in OP's graph. Simply lowering the Boost voltage or raising the charging limit voltage to allow for the wiggle provides constant charging without all the instability. Personally I just raised the charge limit voltage 100mV since I have a BMS to cutoff the pack anyways, I set the boost voltage as desired and now there are no issues.


The blame here can probably still be placed on Epever because if they are going to enforce any rules then they should also enforce these gaps between limits that conflict due to voltage/regulation noise.
very interesting about the charge voltage settings and required difference in value.

in the past, pretty sure i configured an epever solar charge controller with the same values as you mention, which could result in the flipping between modes condition.

thanks for mentioning this!
 
Settings on the Epever are confusing and some of the values relate to the charge control and some to the load outputs, the manual is not very clear on this.) Load output settings and warnings are shown in italics

note changes have been made to this post due to significant errors in the original posting. My apologies for inaccurate statements.

Alternative chargers may adopt different terminology to EPever.

Boost charge voltage = absorption voltage
Boost duration = absorption time



Over volts disconnect : if the battery volts exceed this , the load outputs disconnect from the load from the battery.

Charging limit voltage: if the battery volts exceed this, charging the battery from solar is stopped.

Over Voltage reconnect: if the load outputs have been disconnected due to the battery exceeding over voltage a reconnect will occur at this value.

Equalize charge voltage: used for lead acid batteries where a higher voltage is applied every 28 days for a duration to equalise the cells. Normally only used with flooded batteries. Use with sealed, AGM and GEL lead batteries only with manufactures approval.

Boost charge voltage: under the boost mode, the controller will charge the battery at maximum power from the solar panels until this value is reached. At all times before this 'target' voltage is reached the maximum power control process will will try to 'pull' maximum power from the panels. This is the bulk stage of charging where most of the battery capacity is restored.

Float charge voltage: once the boost duration has been completed the controller will modify the maximum power search and load the panels to produce a constant float voltage at the battery. Typically used for lead acid batteries to compensate for the self discharge. With lead acid batteries it may also 'top up' the battery. Where lithium batteries are charged setting to the resting voltage of the battery may be used.

Boost reconnect voltage: once the unit is in float mode the voltage may vary due to solar conditions and any load on the battery. If the battery voltage falls to this value the controller re enters the Boost stage.

Low voltage reconnect: if the load outputs have been disconnected due to a low battery, this voltage is the turn on value.

Under voltage warning re connect: warning turned off at this voltage.

Under voltage warning: warning set at this voltage.

Low voltage disconnect: load outputs are disconnected from the battery at this voltage.

Discharging limit voltage: other than issuing a warning at the set voltage the stand alone unit cannot do anything about this.

Equalize Duration: the time duration where the voltage is held constant with equalisation for lead acid batteries

Boost Duration: once the boost voltage has been reached the voltage will be held constant for this period. This is the absorption period where the battery is completely charged.

.
Battleborn suggest the following settings, note over time Batleborn have made changes to recommended settings.
Latest suggested settings.
Note only the bold settings relate to charging

Over Voltage Disconnect 14.7 V
Charging Limit Voltage 14.6 V
Over Voltage Reconnect 14.6 V
Equalize Charging Voltage 14.4 V ( this is not used for lithium, set a safe value)
Boost Charging Voltage 14.2 to 14.6 V, 14.4 ideal
Float Charging Voltage 13.6 V
Boost Reconnect 13.3 V
Low Voltage Reconnect 11
Under Voltage Warning Reconnect Voltage 11.5
Under Voltage Warning 11.5
Low Voltage Disconnect 10.0
Discharging Limit Voltage 10.5
Equalize Duration 0
Boost Duration 30 minutes for each 100Ah of battery


For user programming you will need the MT50 or interface cables for Android or PC.

The Boost at 14.6 and float at 13.6 may be considered by some as too high and may wish to adopt more conservative values.

Mike
Hi @mikefitz . I know this is an old post but I have a question you might be able to help me with.

I'm trying to understand what boost duration to use.

Once lifpo4 cells hit 14.6v, what's the rationale for keeping it there for any length of time?

Is it for balancing time?

I'm using a balancer that only balances while current is flowing into the cells. So at a steady 14.6 say it's not doing any balancing.

I have a 480ah battery. Realistically it gets about 20-30amps of charge during the daytime, far below the 0.5C-0.3C recommend charge current, so would this again be a reason not to have a long boost duration, if any at all?
 
<SNIP>

Regarding Victron, they lost my respect with the "dummied up" 500RPM alternator burn out routine on youtube. Their equipment is way beyond my price range and their using bluetooth as the only interface to their controllers is a show stopper for me because I like the small MT50-style display I can walk by and quickly see the flashing solar "live" light with an amp indication into the battery. True a shunt monitor also shows if a charge is taking place and these are the 2 gauges that I't like to mount as this is what I have been living with using the lead/acid setup, both the shunt monitor and a charge controller monitor. I already have the shunt coulomb counter based monitor and I want to also mount the controller monitor. So that is why Victron doesn't meet my needs, there's no wall-mount meter and their solutions are too high-tech, bulky and out of my price range.

Regarding alternator charging, my somewhat unique situation seems excellent for direct alternator charging. The stock vehicle came with a 150A alternator and a AGM lead/acid for chassis starting, engine computer, lamps etc. The dash electronics and headlamps provide a 30-45A constant load. The rest of the 150A is up for grabs The motorhome factory wiring sends a "engine running" signal to a 200A solenoid that conducts to bridge the positive battery terminals from the chassis battery post via a 2/0 cable for a total distance of about 15' to the "leisure/house" battery. The voltage measured at the alternator is typically 14.2 in a lead/acid environment and you are correct that the internal resistance of the LiFePo4s does pull the alternator voltage to 13.8V but apparently the resistance of that 2/0 15' run is enough to keep the alternator from going up in flames. I have both a hall effect amp meter and temperature probe on the alternator diode array and even at an idling speed of around 700 for the diesel, the pulley up-spin has the alternator rotating at least twice that fast. The load of a 4s280aH bank managed by a JBD BMS has only about a 55A draw on the system at a 35% SOC and watching the idling alternator over a period of about an hour, the maximum temperature read across the diode block climbs up to about 80C at idling speeds. For an increase to about 1200RPM (2400 equivalent alternator RPM) will cool the diodes down to about 60C while only increasing output to about 60A total. Additionally the jumping or boosting needed is very infrequent and in most cases the lead/acid still has a slight bit of charge that can be envigorated if it is bridged, where the lead/acid becomes sort of a large capacitor to keep the amp draw from skyrocketting in the emergency situation where one would have to emulate a jump-off from the lithium "leisure/house" battery pack to start the engine.

</SNIP>

I just wanted to add this about "alternator charging". I built and tested a motor powered alternator setup. In said setup I started with a 24vdc alternator. I stripped out the regulator and the diode pack. In its place I set up a potentiometer for the field (with a little engineering and experimentation a resistor or series of resistors would be fine). I also put a three phase 600v bridge rectifier on the output of the alternator (straight off the windings). This was all run into an Epsolar Tracker BN input.

While I had (if i recall correctly) 70+ volts coming off the rectifier, the alternator and MPPT handled this like a champ. In fact the alternator LOVED the higher voltage to keep it cool. In comparison, I hooked a 24vdc intact alternator originally. After about 1 hour or so I could smell the windings and could not touch the alternator. This also fried the VR which is what saved the windings. Note this was before my conversion to LiFePo4 batteries and was done with AGM batteries.

With the conversion I needed a grid charger. Not having had luck with a "real" grid charger, I experimented. I bought the cheapest IGBT stick welder I could find on Amazon. For the last two years I have been using this, via a knife switch between the panels and the welder, to charge my batteries in a pinch. All voltages and currents are right where they should be when in use. The MPPT also throttles it back when close to full. At $99.00 it sure beats the $300+ charger I had before that died when I hooked it up to a generator! It also has the advantage of being a functional (barely :) ) welder.

The only concern I had was "ripple" at the rectification circuit. The Epsolar handles this like a champ. No filtering was necessary.

Next "experiment" will be with an Chinese EV "range extender". These I have 2 and are very interesting for systems 48vdc and above. The beauty is also they are self starting and stopping based on battery condition.
 
Hi andyP,
It's unlikely the battery is accepting charge at 14.6 volts as this usually causes the battery to enter protection due to cell overvolts.
As you suggest, with low charge current compared to capacity, a long absorbtion period is not needed. Its probable the battery is almost fully charged by the time the charge volts reach 14.0 volts.
Use a charge voltage that does not cause BMS protection. 14.2 volts is suitable absorbtion value in many cases, with a 15 to 30 minutes absorbtion period.
 
Hi andyP,
It's unlikely the battery is accepting charge at 14.6 volts as this usually causes the battery to enter protection due to cell overvolts.
As you suggest, with low charge current compared to capacity, a long absorbtion period is not needed. Its probable the battery is almost fully charged by the time the charge volts reach 14.0 volts.
Use a charge voltage that does not cause BMS protection. 14.2 volts is suitable absorbtion value in many cases, with a 15 to 30 minutes absorbtion period.
Thanks.
 
I stripped out the regulator and the diode pack. In its place I set up a potentiometer for the field (with a little engineering and experimentation a resistor or series of resistors would be fine).
Add a thermistor attached to the rear casing of the alternator to be part of your field coil control circuit to drop the field voltage at a certain degree mark, try starting with 120C cut and 100C restore, that will let the alternator live to another day. Also high voltage will not keep coils cool, only speeding up the rotation of the alternator and thus the fan speed will cool the coil. Also keep in mind that with bench experiments, the actual RPM of the tach on the dash of a van, RV or auto is multiplied sometimes 4-5x with the gear up off the flywheel to the typically tiny-by-comparison alternator shaft. So the bench burn-up tests people seem to enjoy with their electric-motor driven alternator tests running in the 500 RPM range are not delivering the actual alternator RPM found on an alternator installed on a vehicle. That's why the Victron demo with the little block that flashes "500 RPM" while the alternator is starting to catch fire is a farce.

Good experiment with the MPPT, however, and I'd like to see your results once you install the safety device of high temp cut-off or voltage drop plus bring the alternator shaft speed more in line with true idling vehicle speed (assuming you are going for a burn-test rather than an output-test). Thanks for the experiment and sorry for the several hundred dollar investment lost in the alternator likely.
 
Back
Top