Lithium Battery Upgrade

[fstruys]

I am hopeful that someone else may have successfully completed a Lithium battery upgrade that includes increasing their charging capacity. Most lithium batteries can be (and should) be charged with 100 or more amps available per battery to insure complete charging for best performance & optimum life.

I have recently replaced my four 8D AGM batteries with 3 LifeBlue LB12300LT batteries & added a second inverter/charger. The original Magnum MS2812 has worked well with my previous batteries but has a maximum output current of only 125 amps.
My hope in adding a Xantrex RS3000 was to improve inverter output by 3000 more watts but primarily to add 150 amps of charging capacity for the lithiums. I have wired the second inverter to the middle A/C unit with the intent to run it in the late afternoon & early evenings when dry-camping in hot weather. That feature now works very well from the lithium batteries!
However, as there is no lithium-specific battery selection on the RS3000, using the Xantrex-suggested GEL mode only charges until the batteries reach 13.8 volts, well below the actual voltage needed to fully charge lithium batteries, causing the RS3000 to shut down early!
One thought would be to use Microsoft's MS View software to set lithium-specific parameters for the RS3000's CUSTOM battery selection mode. Another thought would be to manually select the EQUALIZE mode, set to 14.6 volts whenever recharging the lithium batteries from the generator or shore power?
I would be very interested in hearing from others who have increased their charging current to an ideal 250 to 350 amp capacity. Thank you all for 'hearing' me out!



Felix & Becky
2007 CC Allure Sunset Bay #31448

[Persistent]

It looks to me like your charging system is adequate. 13.8 volts at the end of the charging cycle is acceptable according to Life Blue specifications.

LifeBlue LB12300LT batteries, 120 to 150 amps charge rate x 3 = 360 to 450 amps, 13.8 to 14.8 volts charging. “You do not need a special "Lithium" capable charger. Some multi-stage converters will not work but any standard CV converter that can output 13.8 Volts or higher will work.”

Magnum MS2812 125 amps max with current reduction on low AC input voltage

Xantrex RS3000 150 amps max with different limiting settings

I skimmed both charger manuals. Assuming both chargers are charging at the same time and battery bank is at a low SoC, there should be 275 amps of charging current available. The Li bank will absorb all of that.

Voltage will drop as chargers limit current to their maximums. (Check total charging current and voltage to verify this.) You cannot get more current or higher voltage from the chargers during this phase. This is often called “bulk” charge phase.

Voltage will rise and current will drop near the end of the charge cycle as the Li battery management system starts cutting charge current. By that time the Magnum will limit voltage to 13.6 or so. It will have passed the period the Magnum would supply 14.4 volts. Actual voltage varies due to settings and temperature sensor.

I did not see what the Xantrex will do. It may have different behaviors depending on settings. The Xantrex may also limit voltage to the 13.8 range. This is what is necessary for lead acid charging. Voltage will likely vary depending on temperature and settings.

There are a number of settings in the Xantrex which will limit current output including low AC input voltage. Check these setting to insure maximum available charging current.

The Magnum will also limit charging current under certain conditions. It may limit if temperature sensor is hot and due to other things. If there is a setting to disable the temp sensor, set it to the cold if possible. That will provide the highest finishing voltage. Check that settings are not limiting current.

If you can get finishing voltage up to 13.8, that is all the batteries required.

https://www.xantrex.com/documents/Di...-01_rev-D).pdf

https://www.magnum-dimensions.com/si...-MS-Series.pdf

https://www.lifebluebattery.com/rv-b...%20Sheet-2.pdf

https://www.lifebluebattery.com/rv-b...m-battery.html

[fstruys]

Thank you for your input, Paul. I appreciate the documents you have linked but already have them & have been reading them closely & thoroughly. I have also received several responses from Tech Support at Xantrex about their recommendations for setting the RS3000 for optimum charging for my lithiums, although they would 'prefer' that I buy a new, "Lithium-friendly" Xantrex inverter/charger (limited to only 150 amps!) and new System Control Panel. When I bought my three LB12300LTs from AM Solar this past summer, they gave me a CHARGER SETTINGS document of their own design.
I have been testing my entire system & documenting the charger currents supplied by the MS2812 & RS3000 with the batteries at several SOC levels, ie., 70%, 60%, 50% & 40%. It appears that the current supplied by the Xantrex remains much lower than the 150 amps I was hoping for. At the lowest SOC level, 40% so far during my testing, I saw 125 amps supplied by the Magnum and only 25 amps supplied by the Xantrex. This has been somewhat the same at the various SOC levels I have recorded.

The primary reason I added the Xantrex to my RV was the hope to dramatically increase the charger current capacity, which the lithiums can easily handle, and significantly reduce my generator run time. When I dry-camp, most of the time, I would like to run the generator as little as possible, fully charging the lithiums when I do run it.
I have scoured the internet looking for a constant voltage/constant current charger for my 12 volt LiFePo4 batteries, but 100 amps is the max size I have found. If I found something at 150 - 200 amps that could supplement my Magnum OR 300 amps stand-alone, I would buy it in an instant!
Any ideas?


Felix & Becky
2007 CC Allure Sunset Bay #31448

[Persistent]

The Xantrex is clearly capable of a lot more. I would focus on the complected settings that may be limiting output.

Contact Xantrex again. See if they can come up with settings that are better.

Another temporary path would be to switch the Magnum 120 volt input circuit breaker "off". See what the Xantrex puts out while working alone. If you still can't get near 150 amps, then there is definitely something wrong with the Xantrex.

Switch the Magnum back "on". Does the Xantrex cut back or keep going? The voltage output from the Magnum may be causing the Xantrex to decide the "lead acid" battery is nearly fully charged.

Electronics micro processor programmers can make their creations walk, talk, and blink their big blue eyes at you. There is no telling what they have done in the Xantrex.

The key is in the voltages output by the two chargers. Under size cables in various configurations can also change connector voltages enough to change charger behavior.

Run separate cable from each charger to the battery bank. Connect each cable to a different battery terminal. Do the same for ground (negative) cable. This will limit contact resistance and cable voltage changes that may cause the Xantrex to think batteries are nearly charged.

Measure voltage at charger outputs. Measure voltage at battery terminals. A few tenths of a volt can make all the difference. Repeat with each charger running alone. Voltages above 12.7 volts may trigger float charging.

Reread the manuals. They may tell you what voltage will trigger bulk charge. Contact Xantrex for the voltage if necessary.

[hclarkx]

Originally Posted by fstruys

I am hopeful that someone else may have successfully completed a Lithium battery upgrade that includes increasing their charging capacity. Most lithium batteries can be (and should) be charged with 100 or more amps available per battery to insure complete charging for best performance & optimum life.

See underlined above. I'd be interested to know where this thinking comes from. It's contrary to everything I've read about LiFePO4 charging.

And there's a problem with high-current charging of the LifeBlue LB12300LT.

There's also a problem with limiting charging of the LifeBlue LB12300LT to 13.8 Volts.

As a long-time user of this battery (Gens I, II and III), I've come to know it well.

High current charging will speed through the balancing stage (14.2 to 14.4 or 14.5 or 14.6V) and may thus not allow enough balancing time to keep the cells balanced. Lifeblue has previously specified 15 minutes of constant voltage charging following the constant current bulk stage. This is seemingly to provide more balancing time. The Gen III battery data sheet says 1-15 minutes, so something may have changed. However, not all Li chargers provide this (and in my experience it may not be enough in any event).

The high current charging will also contribute to unbalance. You may end up with unbalance that will reduce battery life to some extent and will limit capacity to some extent. In addition, the Lifeblue will halt charging when one cell hits 3.8 Volts which can easily occur if unbalance is allowed to develop. Load current is not halted.

Similarly, charging only to 13.8 Volts may mean no balancing whatsoever as the Gen I and II Lifeblue batteries start balancing at 14.2 Volts. My Gen III seems to be the same. The aforementioned effects of not keeping the cells balanced apply. And, once unbalance occurs, it's difficult to correct. Incidentally, the web page for the Gen III does say you can charge at 13.8-14.6V, but the spec sheet says 14.2-14.6V.

Not to mention the thermal effects of high charging rates. While the battery is rated for high charge currents, nowhere have I seen anything from Lifeblue listing the advantages you mention. LiFePO4 batteries don't develop much heat, but if you are in a situation where the battery is already quite warm, the added heat from high charging current is definitely not desirable. Not a battery killer, but not the best practice either.

Don't get me wrong, the LB12300LT is a superior design in most respects, but, like most LiFePO4 batteries, does have some quirks that are unfortunately not detailed in the user instructions.

[fstruys]

Perhaps my statement about "best performance & optimum life" was too broad a statement with a measure of "wishful thinking" thrown in for good measure.
To clarify, I interpreted LifeBlue's datasheet as implying charging should be done at "14.2 - 14.6 volts" at a "recommended" current of 120 amps per battery. A lower voltage would not insure near 100% SOC and if the "150 amps maximum / 120 amps recommended" is not available, a lower charge current supply would require a longer charging time and if sufficient time is not available, result in a less-than-optimum full charge.
For those of us that do a lot of dry camping, or camping where generator run times are often limited to a couple of hours in the mid-morning & another 2 hours around suppertime, supplying sufficient charge voltage and current, within the battery mfr's imitations, would insure a full charge within those short hours. If not for those limited hours, it wouldn't really matter how much longer it takes to fully charge lithium batteries, besides having to listen to the noise.
As a part of my lithium upgrade, I replaced all 12 volt wiring to the 3 batteries & to both inverter/chargers with new, 4/0 premium welding wire & all new, hydraulically, double-crimped terminals. All 3 LB12300LT batteries have exactly the same length positive & negative cables to the positive & negative bus bars as well. I also replaced the alternator, starter motor & other high-current 2/0 cable with the new, 4/0 cables & crimps.
I am guessing that the lead-acid-type-only charge parameters are the primary cause of the Xantrex's current poor performance. I removed it from my 1997 Monaco after 8 years of perfect operation maintaining the four L16 AGMs I installed & were still working well into their eighth year of life when I sold that RV. (Prior to selling it, I reinstalled the original Xantrex Freedom 2000 watt inverter/charger installed by Monaco).
I will continue testing & monitoring the performance of both chargers and post my results.



Felix & Becky
2007 CC Allure Sunset Bay #31448

[fstruys]

I should have probably started this thread by describing my line of thinking when deciding to install LiFePo4 batteries. Please, correct me or share your thoughts on the following strategy:


Over the past few years, with the help of a Victron BMS, I have found my average daily use of amp hours when dry camping is roughly 275ah per day. Installing 900ah of lithium should give me at least 2 days without running the generator based upon 550ah of consumption plus an additional 15% (90ah) to compensate for system losses & inefficiencies, totaling 640ah over 2 days. The batteries would now be at roughly 30% SOC assuming no other charging source was used. But I have 1700 watts of solar that typically generate a minimum of 20amps between 9AM to 3PM in the winter months.
If I add the 20amps for 6 hours, minimum values that I have recorded over the past 2 years, the batteries would receive a charge of 120ah per day, confirmed by the Victron BMS.
My 2-day consumption of 640ah offset by 240ah of solar charging equals roughly 400ah of true battery usage and should leave an SOC above 50% These "rounded off" calculations appear to be realistic. In addition, I had also hoped that by having 275 amps of charging capacity when running the generator, I could theoretically be "replacing" 550ah during 2 hours of generator run time. I thereby had hoped that running the generator for 2 hours every second or third day would keep my battery SOC close to or above 50%.

I am open to corrections, suggestions or any input to help me understand why this strategy doesn't seem to work out.


Felix & Becky
2007 CC Allure Sunset Bay #31448

[paul65k]

Originally Posted by fstruys

I am hopeful that someone else may have successfully completed a Lithium battery upgrade that includes increasing their charging capacity. Most lithium batteries can be (and should) be charged with 100 or more amps available per battery to insure complete charging for best performance & optimum life.

I have recently replaced my four 8D AGM batteries with 3 LifeBlue LB12300LT batteries & added a second inverter/charger. The original Magnum MS2812 has worked well with my previous batteries but has a maximum output current of only 125 amps.
My hope in adding a Xantrex RS3000 was to improve inverter output by 3000 more watts but primarily to add 150 amps of charging capacity for the lithiums. I have wired the second inverter to the middle A/C unit with the intent to run it in the late afternoon & early evenings when dry-camping in hot weather. That feature now works very well from the lithium batteries!
However, as there is no lithium-specific battery selection on the RS3000, using the Xantrex-suggested GEL mode only charges until the batteries reach 13.8 volts, well below the actual voltage needed to fully charge lithium batteries, causing the RS3000 to shut down early!
One thought would be to use Microsoft's MS View software to set lithium-specific parameters for the RS3000's CUSTOM battery selection mode. Another thought would be to manually select the EQUALIZE mode, set to 14.6 volts whenever recharging the lithium batteries from the generator or shore power?
I would be very interested in hearing from others who have increased their charging current to an ideal 250 to 350 amp capacity. Thank you all for 'hearing' me out!



Felix & Becky
2007 CC Allure Sunset Bay #31448

Hi Felix, Sorry I'm late to the party on this one. I am running a similar system with 1600W of Solar, 1050 Ah of LiFePO4 batteries, and dual 3000W Victron Inverters rated at 140A each or 280A total.

We are actually seeing a little better performance than your assumptions in the winter, but pretty close.

We see ~260-263A to the batteries per the BMV712 when running the generator or on a 50A shore power circuit and as much as ~320A if the solar panels are cooking along at full sun.

During the summer we rarely ever need to run the generator and our daily Amp draw is actually a little higher than yours if we are running the DVR, otherwise very similar.

Last week in Quartzsite with some pretty good sun we were getting back to 97-100% every day with the DVR off and around 88-92% with it on. If I was worried about getting back to 100% a 15-20 minute run of the generator would likely get us there, but we didn't worry about that as we were still at 70% on the morning of our departure and were able to get back to 100% on the DC-DC converters and solar within about 90 minutes.

Hope this helps??

[hclarkx]

Originally Posted by fstruys

Perhaps my statement about "best performance & optimum life" was too broad a statement with a measure of "wishful thinking" thrown in for good measure.
To clarify, I interpreted LifeBlue's datasheet as implying charging should be done at "14.2 - 14.6 volts" at a "recommended" current of 120 amps per battery. A lower voltage would not insure near 100% SOC and if the "150 amps maximum / 120 amps recommended" is not available, a lower charge current supply would require a longer charging time and if sufficient time is not available, result in a less-than-optimum full charge.
For those of us that do a lot of dry camping, or camping where generator run times are often limited to a couple of hours in the mid-morning & another 2 hours around suppertime, supplying sufficient charge voltage and current, within the battery mfr's imitations, would insure a full charge within those short hours. If not for those limited hours, it wouldn't really matter how much longer it takes to fully charge lithium batteries, besides having to listen to the noise.
As a part of my lithium upgrade, I replaced all 12 volt wiring to the 3 batteries & to both inverter/chargers with new, 4/0 premium welding wire & all new, hydraulically, double-crimped terminals. All 3 LB12300LT batteries have exactly the same length positive & negative cables to the positive & negative bus bars as well. I also replaced the alternator, starter motor & other high-current 2/0 cable with the new, 4/0 cables & crimps.
I am guessing that the lead-acid-type-only charge parameters are the primary cause of the Xantrex's current poor performance. I removed it from my 1997 Monaco after 8 years of perfect operation maintaining the four L16 AGMs I installed & were still working well into their eighth year of life when I sold that RV. (Prior to selling it, I reinstalled the original Xantrex Freedom 2000 watt inverter/charger installed by Monaco).
I will continue testing & monitoring the performance of both chargers and post my results.

Felix & Becky
2007 CC Allure Sunset Bay #31448

You have the LB 12300D LT battery, correct? Not that it matters. The spec sheet recommends charging form "1-120" amps. Maximum is 150 amps (this is a BMS limitation, not a battery limitation). So Lifeblue's spec to keep the charge rate under 120 amps is for battery life purposes (it is not a BMS limitation). This suggests lower is better. Also, it's well known that "chemical activity" is what limits LiFePO4 life and higher charge rate means more "activity" as does storage at higher SOC levels.

I'm not sure I've seen a life vs charge rate graph, but in the technical papers I read there might have been one. When LiFePO4 became a thing, grad students and profs went wild with the technology. I got my education reading there, not on the internet. And from spec sheets.

Interestingly, there are some exceptions. Battleborn changed their recommendation for storage to "charge to 100% and pull the plug." This was clearly not the best practice, but I'd guess made things easier for their customers and cut the number of calls without much loss of battery life (though that would mean more batteries going out the door 10 years from now).

All that said, I'm good with needing faster charging for dry camping. Spending a bit of battery life to reduce generator running time is a good investment in my book. As I mentioned earlier, this is not best for a long battery life, but isn't a huge factor, so isn't ruled out by any means. Peace of mind from a quiet environment is worth a lot.

My situation is 100% dry camping (4-5 months per year) and a goal of 100% of charging from solar. I have not run our generator in six years. Whenever we've had have a close call and almost need the generator, I've upgraded the solar!

In my post I reacted to your mention of battery life and didn't pay much heed to the charging problem. There I don't have much experience since I charge only from solar controllers. But, what you said about 13.8 needs a bit more depth. 13.8V will charge a LiFePO4 to 100%. It just takes a while.

Your goal of faster charging right up to 100% to limit generator run time probably isn't going to happen. All chargers will taper off as battery voltage rises. That's the nature of the beast. I.e., if you set the charger to 14.6V you will get it's rated maximum charge rate when the batteries are down around 13.3V(with charging applied) and up from there some amount. Then the current will drop. The current will drop as battery voltage rises and more quickly as you close in on the "absorb" voltage setting, approaching zero asymptotically at, say, 14.6V. I.e., even with a 14.6V charger you get very little charging at 14.5 Volts and not much more at 14.4V and so on. I don't think there's a charger made that will charge at a given currnet, say 120 amps, right up to 100% SOC. It's possible to do but would be a complicated process. And you probably would not want that given that chemical activity issue. I think the loss of life might loom a bit larger.

So, what you are looking for is a charger with tight regulation on both its internal voltage and its current limiter and low internal resistance. Ideally you could see a typical charge curve from the charger and pick one that provides the highest current at the higher voltages, say up around 14V. I'm not sure any manufacturer provides this.

I'm probably not the first one to suggest this ... how about some solar? A trick with AGM batteries is to do the bulk charge with the generator in the morning and the let solar handle the asborb task over the remainder of the day which requires only modest current. You could do something similar. Pack in enough Ah with the generator to get you marginally through the next night, then let a modest solar array provide additional charging which you would reap the benefits of the next morning (via less generator run time). Since the generator won't be providing much charge current toward the end of the charge period, it wouldn't take much of a solar array to take over. I'm assuming here that you don't use much electrical energy during the day.

I have to say something about your 12V system. Real men don't build big systems at 12V. Just kidding of course. My own system is heading for 720 Ah of battery and 2200W of solar at 12V. My son has 840 Ah of LiFePO4 and 2000W of solar. Works great. And economical. And more reliable; a high priority for both of us since we often boondock far from civilization.

[hclarkx]

Originally Posted by fstruys

I should have probably started this thread by describing my line of thinking when deciding to install LiFePo4 batteries. Please, correct me or share your thoughts on the following strategy:


Over the past few years, with the help of a Victron BMS, I have found my average daily use of amp hours when dry camping is roughly 275ah per day. Installing 900ah of lithium should give me at least 2 days without running the generator based upon 550ah of consumption plus an additional 15% (90ah) to compensate for system losses & inefficiencies, totaling 640ah over 2 days. The batteries would now be at roughly 30% SOC assuming no other charging source was used. But I have 1700 watts of solar that typically generate a minimum of 20amps between 9AM to 3PM in the winter months.
If I add the 20amps for 6 hours, minimum values that I have recorded over the past 2 years, the batteries would receive a charge of 120ah per day, confirmed by the Victron BMS.
My 2-day consumption of 640ah offset by 240ah of solar charging equals roughly 400ah of true battery usage and should leave an SOC above 50% These "rounded off" calculations appear to be realistic. In addition, I had also hoped that by having 275 amps of charging capacity when running the generator, I could theoretically be "replacing" 550ah during 2 hours of generator run time. I thereby had hoped that running the generator for 2 hours every second or third day would keep my battery SOC close to or above 50%.



I am open to corrections, suggestions or any input to help me understand why this strategy doesn't seem to work out.


Felix & Becky
2007 CC Allure Sunset Bay #31448

Very helpful update.

With that much solar, I retract my solar recommendation. You are right to get what you can from the solar and finish the job in the evening with the generator. My DW would not be out there dry camping with me if I did that, but there seems to be no work-around in your case.

275 Ah is a lot of usage. Can you share what your loads are? Running air conditioning from your batteries? What type of air conditioning units?

You mention 15% for inefficiencies; isn't that included if your 275 Ah is measured at the batteries? Or is the 275 your projected loads at 12 and 120V?

[fstruys]

I chose to keep my system all 12 volt as I learned from the 1000 watt array on my 1997 Monaco that partial shading is a REALLY big issue, especially here in the Pacific Northwest. I built a very flexible combiner box that allowed me to configure my ten 100 watt panels in various output voltages within the 150 volt limitation of my MS-MPPT-60 charge controller. I settled on a 12 volt array with all panels in parallel as that had the lowest shading losses. My 2007 RV has 1700 watts; also all in parallel.
I sell, install & service a variety of medical imaging systems rated from 15kW to 100kW, so I have a generous collection of medical grade 4/0 wiring & terminals and a Milwaukee hydraulic die crimper that I spent a fortune on &, probably, never used enough to justify! My solar chargers generally output more charge current (I can see 15 amp on a foggy day) than I quoted and realistically see them provide 50 amps on an average winter day. Per the Victron BMV, I averaged 275ah at the batteries, but "threw in" the extra 15% just to be sure. I wanted to be on the low side of all calaculations!

Yes, they are LifeBlue LB12300LTs as I do a lot of winter camping and really liked their built in heaters allowing charging down to -4 degrees F! I would hope that I could utilize the Xantrex for additional charging capacity. Bulk charging from the generator with both chargers at 275 amps for 2 hours, then continuing with solar the rest of the time was going to be the solution! My DW would not travel in the RV without TV, which means almost 200ah per day alone!


Felix & Becky
2007 CC Allure Sunset Bay #31448

[hclarkx]

We haven't been to the Northwest since going solar in 2015. Up there trees are bad enough, but a lot of clouds get in the way as well. Most of our haunts can be finessed with the use of Google Earth to find clearings where we can point the tail south (our roof slopes toward the rear and 1600W are on that part of the roof). This is critical since our camping is mostly fall/winter/spring. I'm lucky, DW records a terabyte at home while we are away and binge watches for a month after we get home. I just need to figure out how to cast to the screen on her Peloton exercise bike. On the road it's Prime downloads on a 5k 12.4" tablet propped up between the recliners.

I hope the faster charging works out. Let us know.

[fstruys]

Thank you for your input & suggestions. I have been monitoring the individual charger current values supplied by my Xantrex RS3000 and my Magnum MS2812 when operating only one charger at a time. The MS2812 supplies 125 amps when it is charging my lithium batteries but the RS3000 never supplies more than 25 amps. Even though I have it "set" for a Gel battery, as recommended by Xantrex Tech Support, I don't think the lithium battery voltage ever drops low enough for the RS3000 to charge supplying it's full 150 amp capability.

I know that the RS3000 can supply 150 amps as I removed it from my previous RV where I have frequently seen it do so when dry camping & trying to delay running the generator as long as possible. I would regularly drop my four L16 LifeLine AGMs to 50% SOC before recharging them. I may have mentioned that Xantrex Tech Support was of very little help other than suggesting I buy one of their Lithium-Compatible inverter/chargers. I have really enjoyed using the RS3000 in my '97 Monaco, using it over eight years, traveling almost 100k miles, but with that type of customer support, I seriously doubt that I would buy anything else Xantrex makes!

There is a "custom" battery choice in the selection menu that I was told could be set to higher charger voltages, but they didn't offer any help to program new settings. I don't think the RS3000 was a very popular model but was installed as original equipment in a few Country Coach models. Anyone else have experience with programming the "custom" battery selection on an RS2000 or RS3000? Thank.


Felix & Becky
2007 CC Allure Sunset Bay #31448