Balmar 614 vs Li battery BMS cutout

[s/v Jedi]

Originally Posted by Karanga

Just to follow up on this, FYI.

I have installed 3 x 200 A/hr lithium batteries, plus a 20 A/hr small car starter lead acid battery in parallel. The lead battery circuit has a separate isolation switch, so that it can be disconnected from the rest of the battery bank, if desired.
So far, the system is working very well. Charging via genset at 120amps gets the batteries full. This has temperature sensor monitoring
Charging via Balmar 180amp alternator and 614 regulator is going well and gets to full charge. This also has a battery temperature sensor. Plus I have derated the belt loading to setting of 3 (as per Balmar instructions), but I have left the charging profile the same as it was for the old AGM batteries. (good/bad?).

Discharging is going really well. I haven't gone below about 75% so far, and easily make 2 cups of coffee via the inverter each morning before any solar charging kicks in.
The battery monitoring kit has now become much more important to indicate state of charge, because the voltage sits permanently at 13.25 (not the slow decrease seen with lead batteries).
Importantly, the small lead acid battery appears to make no difference at all to the charging or discharging performance. However, because it can provide approx 400 CCA of starting power, it must be contributing significantly to the anchor windlass, plus the diesel genset starting (off the house bank).
I am assuming that the lead battery is available to serve its primary purpose of creating an emergency amp sink if ever the lithium BMS disconnects the batteries during high rates of charge from the alternator via the 614 regulator. I don't really want to test this...

Tim

Most of what you did sounds good so I’ll comment on the problems:

- You must change the Balmar charging profile; keeping it on AGM will kill the lithium bank. The reason is that the absorption duration is way too long. Also, at low charge rate, it can take a long time at near absorption voltage before absorption is reached, which can mean that the bank is already at 100% before absorption even starts.

- Keep the lead acid battery in there but just ignore it. Consider it a sacrificial part of the installation. A better option exists: isolate starter battery and alternator/starter like conventional installations do but instead of a switch or automatic charging relay or combiner, use a DC-DC charger to charge the lithium bank. This allows you to use the correct charging algorithm for each and keeps the alternator safe as well.

Here are two links; the first one is a long read but skip to the charging part where absorption time etc. is discussed: https://marinehowto.com/lifepo4-batteries-on-boats/

And here is a good read on the alternator regulator: https://marinehowto.com/programming-...age-regulator/

[Maine Sail]

Originally Posted by LeaseOnLife

Also be aware, with the Balmar 614, the target voltage to transition from bulk to absorption charge is a minimum of 14.1V. It will stay in bulk for almost forever, since the LiFePo4 will suck all the power they get and the Voltage won't get to 14.1V until (too) full. I find 14.1V too high for my Lithiums ....

This is not correct. With the MC-614 you can custom program the bv, av and float and 14.1V is not the bottom rage of adjustment for bv. You do however need to program it correctly, and in the correct order, and all this info is included here:
Programming a Balmar Voltage Regulator (LINK)






.

[Maine Sail]

Originally Posted by Karanga

I have a pre-2017 Balmar 614 regulator controlling a Balmar 180amp alternator and I am considering swapping my AGM house battery bank with Lithium.

Make sure your LFP BMS can handle that amount of charge current.

Originally Posted by Karanga

I know I can modify the 614 charging profile, but I do wonder if it is possible for the internal BMS to ever disconnect the battery from the charging, and thereby potentially cause damage to the alternator. The Balmar notes do mention this as a risk, but is it a realistic risk?

A definite risk and it can damage not just the alternator but sensitive marine electronics too as the voltage transient can be quite high. We've replaced and repaired quite a number of BMS load dumped alternators as well as overheated & cooked alternators from LFP banks. That said most recent Balmar alternators are now using avalanche diodes which can help minimize damage but the transient can still damage sensitive marine electronics.

Originally Posted by Karanga

If I set the max (absorption and float) charge to 13.8v, would this mean that the batteries are never quite full so the BMS is less likely to disconnect?
Tim

An LFP cell can be charge to 100% SoC at just a tick over 3.4 VPC (13.6V for a 12V nominal pack). The idea that 13.8V (3.45VPC), for a 12V pack, cannot get an LFP battery to 100% SoC is just not accurate. Drop-In battery makers like to tell this story so you push the cells to their balance point routinely in order to keep the cells in balance. If you don't push to where their BMS balances, the FET BMS's ultra-low balance current may not be able to keep up and you can have BMS disconnects, based on imbalanced cells, even at just 13.8V..

A typical drop-in battery BMS can disconnect for many reasons not just voltage as many folks often assume:

Low Voltage (bank)
High Voltage (bank)
High Single Cell Voltage
Low Single Cell Voltage
BMS Temp (FET's can over heat from charge/discharge @ high rates)
Cell Temp Low
Cell Temp High
Battery Temp Low
Current Limit Exceeded

[rgleason]

Originally Posted by markcouz

I would guess that the Balmar 614 being a costly piece of kit would have programmable voltages and current limiting to suit LiFePO4 - if it doesn't then find something that does!

ARS-5 and MC614 are Fully User Programmable and suitable for LFP. The new MC614 have a faster processor, easier programming and a preset LFP set of parameters. The ARS-5 does not have a direct power connection for the regulator, but uses the sens wire and it is not rated for higher field currents needed for more powerful alternators (I am looking for that rating right now..) ---However if you are intentionally derating an alternator with Belt Load Manager, to about 100a, I am wondering why the ARS-5 would not work?

Both ARS-5 and MC614 have Belt Load Manager " Belt Load Manager widens the regulator’s field pulse bandwidth, thereby reducing load on the drive belt. The Belt Load Manager can also be used to protect the alternator in applications where battery capacity exceed ideal charging ratios."


See Mainsail's Marine How to


It is clear that if we are directly charging the LFP bank, we need a high amp disconnect activated by the BMS.

[rgleason]

Originally Posted by markcouz

You don't need the DC-DC charger, the Balmar 614 can be setup to charge your batteries with a lithium profile...

Your lithium bank will be over 95% charged at 14V, if it takes some time to reach 14.1V who cares- your batteries will charge very fast to a very high SOC, much faster than your previous lead acid. ...

This statement is a little misleading. There are consequences to very fast charging and charging to high SOC, those consequences can and will reduce charge cycles and life and capacity. So it is worthwhile considering the manufacturers limits, but keeping well away from the max C and 100%SoC and 0%SoC is smart, except for the concessional times where you need to get your BMS to top balence for example. There are many other threads that discuss this in the Lithium Battery section. So I suggest reading some of that.


I really like MaineSail's term "“fractional C” use for our boat house bank use of LFP.
https://marinehowto.com/lifepo4-batteries-on-boats/

[Dsanduril]

I really like Frans' take on a hybrid LA/LiFePO4 system and it sounds like that's about where the OP ended up. Where I think it shines is with solar/wind/hydro charging. Once the lithium is full (however you define that) it gets disconnected from the charging system and the LA acts as a buffer for the use/generation. Allows you to capture that afternoon solar capacity (or simply motoring for an extended period with an alternator putting out low current) that might be lost by a lithium BMS simply shutting off the charging sources when the batteries are full.

The lithium doesn't stay full very long, it gets discharged overnight. At the same time the lithium basically floats the LA when there are no charging sources, so there is essentially no cycling of the LA. Seems a neat system and I'm hoping to see a bit more in his OpenHybridBMS development.

[rgleason]

"keeping well away from 100%SoC and 0%SoC is smart" should read
"keeping well away from 100%SoC and 0%DoD is smart"

[rgleason]

Dsanduril,

Can you advise regarding what is 100% Soc? and how sensitive LFP are to overcharging and overdischarge? We've had long discussions about this. Since LFP has little resistance and stays very close to the same voltage for a large portion of the charge cycle (except at the ends where their is a marked drop off in voltage for discharge and a larger voltage increase for charging).
Are there some acceptable schedule for Alternator Charging shutdown voltage with different battery temperatures which also affects expected cycles? IE


Charge Rate | Discharge disconnect | Alt Charge Shutdown Voltage | Expected # Cycles

.1C |
.2C |
.3C |
.4C |
.5C |

[Dsanduril]

Originally Posted by rgleason

Dsanduril,

Can you advise regarding what is 100% Soc? ...

Nope, way above my pay grade. I've seen the (lengthy) discussions. Should you operate between 20% and 80%? 15% and 90%? What is 90%? How do you measure it? For me, but this is solely opinion not backed up with anything other than my own reading, I would consider my batteries 'full' when I got to the beginning of the upper knee (and empty just above the lower knee). This is not maximum capacity according to the battery manufacturer, but is what I think of as the 'operational' maximum. I think MaineSail's approach is pretty similar and he's done far more actual, physical research.

My point is that regardless of the details, most agree that at some point you want to stop charging LiFePO4. You can do that with a very low float setting - probably, but that flat voltage curve makes things difficult, or you can just disconnect your charge sources, or try the hybrid approach. Hybrid has appeal to me because it can be a "drop-in" replacement. Selecting that point for charge cutoff.....

[rgleason]

Originally Posted by Dsanduril

Nope, way above my pay grade. I've seen the (lengthy) discussions. Should you operate between 20% and 80%? 15% and 90%? What is 90%? How do you measure it? For me, but this is solely opinion not backed up with anything other than my own reading, I would consider my batteries 'full' when I got to the beginning of the upper knee (and empty just above the lower knee). This is not maximum capacity according to the battery manufacturer, but is what I think of as the 'operational' maximum. I think MaineSail's approach is pretty similar and he's done far more actual, physical research.

My point is that regardless of the details, most agree that at some point you want to stop charging LiFePO4. You can do that with a very low float setting - probably, but that flat voltage curve makes things difficult, or you can just disconnect your charge sources, or try the hybrid approach. Hybrid has appeal to me because it can be a "drop-in" replacement. Selecting that point for charge cutoff.....

I was going to ask next

"The lithium doesn't stay full very long, it gets discharged overnight."
What is full? but you've given me a good sense of what your range of use is, and exactly the kinds of questions I have! I think we are both in agreement that the range of use should be less than the manufacturer's may list as maximums/minimums, and should be somewhere on those upper and lower knees/knuckles = "operational maximiums".

"or you can just disconnect your charge sources,"

I am going to try to charge LFP directly, with a "properly set external regulator with battery and alternator temperature sensors, with a FLA in parallel to protect the alt from disconnection, but I would also like to disconnect if the BMS shuts down and whenever the Alt is finished charging (don't know if this is necessary however).

May I ask what your settings are for solar and alternator? (I think you have listed this already somewhere in a thread!)

Boy does this page help!! Great graphics diagrams. Lithium Implementations:
https://www.zwerfcat.nl/en/lithium-implementations.html

[rgleason]

This is complicated. Some of what I was trying to explain about Lithium Batteries but much clearer:

Lifetime Expectancy (Scroll down to this.)

Exceeding Manufacturer Limits

Spending too much time in a highly State Of Charge. When the cell is somewhere between 80% and 100% charged, the chemistry within the cell becomes a lot more reactive, especially at elevated temperatures. This causes degradation of the cells.

Lithium batteries degrade when fully charged (Scroll down to)

Lithium batteries love to cycle, but they hate to remain in a fully charged state. Lithium batteries are best kept in a discharged state of around 40% energy left. At a higher State Of Charge (SOC) the chemical components inside the battery become more reactive, especially at a SOC higher than 80% and this becomes even worse at tropical temperatures. The higher the average charge state of the lithium battery, the shorter its lifetime.


At issue here are the following charge routines/choices/strategies:
Charge Rate
Number of lifetime cycles desired vs speed of charge selected.
Temperature of the Batteries
Temperature of the Alternator
Operational ah needed for loads vs # Lifetime cycles vs LFP capacity.
Protection of Alternator from BMS shutdown.
Utilizing charge sources like alternator and solar at partial capacity for current house loads once LFP is full.

[witzgall]

THere are two avenues for setting up the MC-614 for use with LFP batteries. If you have an older MC-614 without the built-in LFP profile, then go to our website and grab the service bulletin for setting it up to use LFP batteries: https://balmar.net/service-bulletins/

If You have a newer MC-614, just simply use the profile, with potential adjustments made for you YOUR battery MFG settings.

With both of these methods, it is VERY IMPORTANT that you do not use temperature compensated charging. The two methods above disable this feature, and of course you should also not connect the Battery Temp sensor as well, or disconnect it if you have one installed. KEEP the Alt tem sensor though!

Chris

Originally Posted by Karanga

Just to follow up on this, FYI.

I have installed 3 x 200 A/hr lithium batteries, plus a 20 A/hr small car starter lead acid battery in parallel. The lead battery circuit has a separate isolation switch, so that it can be disconnected from the rest of the battery bank, if desired.
So far, the system is working very well. Charging via genset at 120amps gets the batteries full. This has temperature sensor monitoring
Charging via Balmar 180amp alternator and 614 regulator is going well and gets to full charge. This also has a battery temperature sensor. Plus I have derated the belt loading to setting of 3 (as per Balmar instructions), but I have left the charging profile the same as it was for the old AGM batteries. (good/bad?).

Discharging is going really well. I haven't gone below about 75% so far, and easily make 2 cups of coffee via the inverter each morning before any solar charging kicks in.
The battery monitoring kit has now become much more important to indicate state of charge, because the voltage sits permanently at 13.25 (not the slow decrease seen with lead batteries).
Importantly, the small lead acid battery appears to make no difference at all to the charging or discharging performance. However, because it can provide approx 400 CCA of starting power, it must be contributing significantly to the anchor windlass, plus the diesel genset starting (off the house bank).
I am assuming that the lead battery is available to serve its primary purpose of creating an emergency amp sink if ever the lithium BMS disconnects the batteries during high rates of charge from the alternator via the 614 regulator. I don't really want to test this...

Tim

[rgleason]

Dear Chris Witzgall


"..of course you should also not connect the Battery Temp sensor as well, or disconnect it"

Ok, I would like to understand why? Is'nt it important to set that at some temp lower than the BMS high temp cutoff?

[OceanPlanet]

Nowadays we use the Wakespeed AP500 (programmable loading curve based on rpm, and programmable engine load limit for engines with CANbus data output) or WS500 (also very capable), networked to the Lithionics BMS CANbus. Aside from the programmed voltage limits (for absorption, float, etc.) the regulators will cut back based on:

Alternator temp - programmable, we usually set for 120C for APS alts, 105C for Balmar or MGDC, etc.

Battery temp - as reported by the BMS, with both reduction and cutoff levels programmable.

Actual battery current - on very powerful charging systems, if AC chargers running at the same time, the current combined with dual powerful alternators may be excessive. Actual current sensed at main neg shunt, and/or from BMS(s).

Engine load - If engine has J1939 CANbus data output, then can be networked together with the alternator regulator(s), in addition to the Li3 BMS.

Engine rpm - charging load ramped up/down, based on engine rpm (rpm acquired from either alternator stator (programmable ratio) or engine CANbus)

There are other controls, however these are the main features. Typically in addition to all of the above controls, the BMS is set up to cut the power to the regulator as well, in the rare case of regulator failure (or programming mistake).

Perhaps the AP500/WS500 are not for everyone, however for charging charging Li (or even large AGM) with powerful alternators, having these controls is a real advantage.

[rgleason]

Here is a statement from a Battleborn installation:
https://www.solar-electric.com/lib/wind-sun/Battleborn_BB10012_specifications.pdf

The Battle Born Battery also requires no new hardware to run in your boat, RV, trailer, or golf cart. Just pull out that grungy old lead acid battery (use two hands, those suckers are heavy), drop in this elegant upgrade, and get yourself out there

This battery has + and - connections, no indicators and no means of communicating. The BMS is configured to protect the battery without much concern about the entire system configuration and charging devices.

However Battleborn seems to think that their battery is fine in FLA configured systems, provided the charging devices are properly set!

Yet OceanPlanet recommends the Wakespeed AP500 which is a sophisticated charger for charging Lithionics exactly why do we have these differences in approach, and what are the risks with the Battleborn approach? Are they significant?