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Lithium Charging w/alternator

After speaking with Balmar, I decided to upgrade my alternator regulator to the MC 614 series which has LiFePO4 programmable settings built in, plus the temperature sensor. I suspect that the AGM starter battery will be just fine since the LFP batteries' BMS uses tolerances acceptable to the AGM.
 
Great plan. Balmar knows their stuff. Since you say that you are limited to 40 amps charging current on each of your two Lithium ion batteries, for a total of 80 Amps, you should look at the Amp Manger feature. It is located in the Advanced Program features and is a setting that will limit the maximum field current and therefore limit the maximum output current of the alternator. Adjustable in 2% increments.

Balmar tech support rocks. I wish all manufacturers of marine stuff was that good.
 
John Simmons said:
I have a balmar mc612 alternator connected to a 12V 1000Ah LiFePho4 bank. I contacted Balmar about what settings should be programmed in, and they were super helpful.

One of the items that they were insistent about installing was a alternator protection device.

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According to Balmar it will save your alternator and any electronics connected to the alternator in case the battery becomes disconnected either through some idiot switching the battery switch to OFF or the BMS taking the main battery offline. When the load is suddenly disconnected from an alternator, the output voltage spikes dramatically and at a minimum the diodes in the alternator are destroyed. The open circuit protection device that Balmar told me to buy keeps a load on the alternator at all times and supposedly keeps this from happening. I have never gone wrong listening to the Balmar tech support. I don’t have the courage to actually test the thing to see if it works though.

I presently have a similar hybrid system. Batt 1 is the house LiFePho4 1000 Ah. Batt 2 is a Lead Acid Starting Battery.

All of my charging sources (Balmar Alternator with MC612, Samlex inverter Charger, and Morning Star MPPT controller are programmed for Lithium charge profile). The BMS I use is the Electrodaucus SBMS0.

The sole exception is ONE 20 Amp Lead Acid Battery 120V charger that is connected to the starting battery for when I am on shore power or when the generator is on.

My usage profile is switch the 1/2/Both/Off battery switch to 2 (Start battery) start the engine or generator and let the alternator charge the starting battery for a few minutes as I pick up the anchor etc. Then I switch over to Battery 1 which is the House LiFePho4 and I just leave it like that.

My use model for the boat while at anchor or while sailing is one to two hours per day of generator run time to make water, cool down,the holding plate, and fast charge the Lithium Bank. At that time the small battery charger is also topping up the start battery. During the day the solar panels are charging the lithium bank.

Note that both banks are separated by the battery switch, but I can combine them if I want as was mentioned in the previous article. I have done that as the voltages are similar enough as to not cause any major problems, but in general the charge voltages of lithium batteries are higher than Lead Acid. If you permanently parallel connect your lead acid with the Lithium, you will overcharge the lead batteries and shorten their life.

My eventual goal is to move to all Lithium and get rid of the lead acid side completely. Unfortunately for me, the starting battery is only 6 months old, so I will continue using this hybrid system.

One of the other boats on the dock has a similar setup and he uses a battery to battery charger to top up his lead acid cells. I am only using the 120V AC charger I have because I already own it, and my stated goal is to move totally to Lithium when the last lead acid dies.

If I was going to keep a lead acid battery permanently, I would go with the Battery to Battery charger.

John.
Click to expand...
Thanks. Great explanation. I’m afraid of paralleling my 200a FLA and 150A LiFePO4 over a 6awg wire I’m using to switch my solar charger to charge the FLA and LiFePO4. What rule could be used the safely parallel the banks? My LFP bank is normally at 13.4 90% SOC for me and FLA maybe 12.5v 95% Soc. I Think the FLA should only take 10a at 95% SOC?
 
FYI you can grab that APD from battleborn w/free shipping for $74 I think
 
Dauntless said:
Check out this hybrid system.
www.zwerfcat.nl

Lithium-Hybrid

What is it and why do you want it?
www.zwerfcat.nl www.zwerfcat.nl

This is the second of such articles on this forum and I found them both very useful.
I now have a hybrid system and it works exactly as advertised, in that my alternator is protected from the BMS disconnecting the battery and the LI gets charged quickly.
Click to expand...

So with this hybrid system I would switch my solar charge controller back to a lead acid charging profile rather than LifePo4 one it is set at now?
 
My 400 Ah of LFPs are installed and everything has been wired up, (still waiting on the delivery of the Balmar MC614). I have reprogrammed my Xantrex LinkPro with the parameters from the Spec sheet that applies to my batteries. But it is not behaving properly. For example, when the batteries are fully charged, it does not say "full" like it should. The other day the hours available showed 120 instead of 240, even though they were thoroughly charged. After I turned on the battery charger at the dock, they went back to 240 h very quickly. It is basically working, showing me the full batteries, but it seems a little buggy. Anybody have this experience?
 
Argosy said:
Click to expand...

I'm not doubting that the phenomonon that they are describing exists, and that their products effectively manage the situation, but their test seems to be biased in that they used a relatively small pulley on the motor, and a relatively large pulley in the alternator resulting in alternator speeds much lower that typical in a automotive application, which exagerates the effect they are demonstrating.

By comparision the crankshaft pully on my Jeep is over 7" in diameter and my alternator pulley is less than 2" in diameter. Even at a 750 RPM idle, my alternatoris turning at over 2600 RPM, and at typical cruising speed the alternator is about 7500 RPM, almost twice the speed of their "highest" speed.

I do completely agree with their conclusions that typical automotive alternators are phenominally inefficient and that the charging Lithium batteries with an alternator is problematic without some way to control the current.

It would be really cool if you could have an ammeter monitoring the charging current and a current adjustment knob, so that you could set the charge current for your drive based on the amount of charge needed and the length of your drive to minimize the impact on fuel economy and only work the alternator as hard as needed to get the charge you needed during the drive.
 
I mean, it kind of does that right? Alternator turns full amps to charge batteries, then it goes down to no output. Same amount of fuel/power provided the efficiency is the same at all RPM (im sure it isnt, but probably a negligible amount difference realistically).

Essentially, because there is no resistance in the LFP battery, the voltage regulator provides full field power at all RPM. This creates lots of heat which burns it out, because its pulling full power with lower fan speed...

The temp sender is $30...
 
I think the problem is that many people in boats and RVs will idle the engine to charge the batteries and if you set the alternator up to spin fast enough to cool at idle you may over rev it when cruising depending on the rev range of your engine.
 
So, my Xantrex LinkPro is not designed to monitor LiFePO4 batteries, per Xantrex. I do have a Blue Sky MPPT controller that gives me pretty good info, and I have a phone app that connects to the BMS's of my batteries. But, I like to have something on my panel. So, any recommendations on something would be a good substitute for my LinkPro?
 
sailing gal said:
The lithiums take a 40 Amp charge each for a total of 80 Amps. If I put a resistor on the alternator, it can reduce output. But, I will contact Balmar and check with them as well. I did locate a temp sensor, but I have been told it is not necessary by local marine electrician, will double check with Balmar.
Click to expand...
You're misunderstanding this point.

1) The LFP battery BMS can only handle 40A or approx 80A for two in parallel.

2) Parallel FET based BMS's is a dangerous path to count on as one high resistance connection, and one battery is taking more current than the other and over loading the BMS.

3) The cells will take what ever you can throw at them but the BMS may not handle that and disconnect. The alternator can still over heat and burn up supplying 80A continuously. No small frame alternator, not even a Balmar, is rated for constant duty and the output rating is a cold rating. Your external regulator should be set up to deliver no more than about 50-60A max to the batteries and it should still utilize an alternator temp sensor.

I've seen many, many, many marine alternators cooked by LiFePO4 batteries and an incorrectly programmed regulator.
 
Sabre36 said:
You're misunderstanding this point.

1) The LFP battery BMS can only handle 40A or approx 80A for two in parallel.

2) Parallel FET based BMS's is a dangerous path to count on as one high resistance connection, and one battery is taking more current than the other and over loading the BMS.

3) The cells will take what ever you can throw at them but the BMS may not handle that and disconnect. The alternator can still over heat and burn up supplying 80A continuously. No small frame alternator, not even a Balmar, is rated for constant duty and the output rating is a cold rating. Your external regulator should be set up to deliver no more than about 50-60A max to the batteries and it should still utilize an alternator temp sensor.

I've seen many, many, many marine alternators cooked by LiFePO4 batteries and an incorrectly programmed regulator.
Click to expand...
I did end up replacing the regulator with an MC 614 and added an alternator temp sensor. I do think I have the bases covered now.
 
Those balmar temp sensors like to fail so its a good idea to keep a spare one around.
 
That battery linked by the OP is L-ion. Not a great idea on a boat. Lifepo4 is a better option. That supplier also has those banks but are currently sold out I believe
 
sailing gal said:
So, my Xantrex LinkPro is not designed to monitor LiFePO4 batteries, per Xantrex. I do have a Blue Sky MPPT controller that gives me pretty good info, and I have a phone app that connects to the BMS's of my batteries. But, I like to have something on my panel. So, any recommendations on something would be a good substitute for my LinkPro?
Click to expand...

I am wondering what xantrex meant when they said it is not designed to monitor the LiFePO4 batteries. The link pro and link lite (which I have) both measure current into and out of the battery via a shunt. Yes, the “fuel gauge” display which is based on the voltage drop of lead acid batteries might not be right, but the voltage of the bank will be displayed as well as the amp hours used, current charge/discharge etc.

Could you please elaborate what Xantrex said about that it was not designed for it? I would love to hear it.

Also, if you are getting rid of it for some reason, I would like to be the first in line to offer to buy it from you! I am presently using the link lite for a 1200Ah bank, and it only allows me to go program up to 1000Ah.
 
Popuptoaster said:
So with this hybrid system I would switch my solar charge controller back to a lead acid charging profile rather than LifePo4 one it is set at now?
Click to expand...

No. You need to protect the Li . So set up for Li and the LA will be fine.
 
John Simmons said:
I am wondering what xantrex meant when they said it is not designed to monitor the LiFePO4 batteries. The link pro and link lite (which I have) both measure current into and out of the battery via a shunt. Yes, the “fuel gauge” display which is based on the voltage drop of lead acid batteries might not be right, but the voltage of the bank will be displayed as well as the amp hours used, current charge/discharge etc.

Could you please elaborate what Xantrex said about that it was not designed for it? I would love to hear it.

Also, if you are getting rid of it for some reason, I would like to be the first in line to offer to buy it from you! I am presently using the link lite for a 1200Ah bank, and it only allows me to go program up to 1000Ah.
Click to expand...
Doing some more research, I found that you need to change the Peukert number on the Xantrex to get a better reading for LFPs.

Here is what Xantrex wrote:
The Link Pro was not designed for lithium batteries, it came out before lithium batteries. That being said, a charge cycle will be considered complete when both Auto-sync parameters F1.0, F1.1 and F1.2 (see Function setup menu) are met.

Since lithium batteries don't drop in voltage until the end and the voltages are higher on lithium batteries, that can be an issue. You can try adjusting the voltage level based on the battery manufacture (F1.0) recommendation. Adjust the float current (F1.1) to a different percentage since lithium batteries usually don't need the float charge and leave F1.2 at 240 seconds.

F5.0 is your battery capacity and I see you've changed that. This means F1.1 would make the float current at 8.1 amps at 2%. That number seems high since float currents are usually around 4 amps on flooded, get or agm batteries.

At any rate, I am keeping my Xantrex. I am still figuring out how to use it with the LFPs.
 
John Simmons said:
I have a balmar mc612 alternator connected to a 12V 1000Ah LiFePho4 bank. I contacted Balmar about what settings should be programmed in, and they were super helpful.

One of the items that they were insistent about installing was a alternator protection device.

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www.electriccarpartscompany.com

According to Balmar it will save your alternator and any electronics connected to the alternator in case the battery becomes disconnected either through some idiot switching the battery switch to OFF or the BMS taking the main battery offline. When the load is suddenly disconnected from an alternator, the output voltage spikes dramatically and at a minimum the diodes in the alternator are destroyed. The open circuit protection device that Balmar told me to buy keeps a load on the alternator at all times and supposedly keeps this from happening. I have never gone wrong listening to the Balmar tech support. I don’t have the courage to actually test the thing to see if it works though.

I presently have a similar hybrid system. Batt 1 is the house LiFePho4 1000 Ah. Batt 2 is a Lead Acid Starting Battery.

All of my charging sources (Balmar Alternator with MC612, Samlex inverter Charger, and Morning Star MPPT controller are programmed for Lithium charge profile). The BMS I use is the Electrodaucus SBMS0.

The sole exception is ONE 20 Amp Lead Acid Battery 120V charger that is connected to the starting battery for when I am on shore power or when the generator is on.

My usage profile is switch the 1/2/Both/Off battery switch to 2 (Start battery) start the engine or generator and let the alternator charge the starting battery for a few minutes as I pick up the anchor etc. Then I switch over to Battery 1 which is the House LiFePho4 and I just leave it like that.

My use model for the boat while at anchor or while sailing is one to two hours per day of generator run time to make water, cool down,the holding plate, and fast charge the Lithium Bank. At that time the small battery charger is also topping up the start battery. During the day the solar panels are charging the lithium bank.

Note that both banks are separated by the battery switch, but I can combine them if I want as was mentioned in the previous article. I have done that as the voltages are similar enough as to not cause any major problems, but in general the charge voltages of lithium batteries are higher than Lead Acid. If you permanently parallel connect your lead acid with the Lithium, you will overcharge the lead batteries and shorten their life.

My eventual goal is to move to all Lithium and get rid of the lead acid side completely. Unfortunately for me, the starting battery is only 6 months old, so I will continue using this hybrid system.

One of the other boats on the dock has a similar setup and he uses a battery to battery charger to top up his lead acid cells. I am only using the 120V AC charger I have because I already own it, and my stated goal is to move totally to Lithium when the last lead acid dies.

If I was going to keep a lead acid battery permanently, I would go with the Battery to Battery charger.

John.
Click to expand...
I did the same thing that you did, installed LFPs for the house bank and left an AGM for my starter battery which is on a completely separate switch. I installed the new Balmar regulator to regulate the LFPs. I wrote to Balmar and asked them if I needed to install anything else in regards to my AGM battery, such as a DC to DC charger. Their answer was NO! They said the AGM would handle the charging just fine (it is only charged by the alternator) and nothing else was required. When I asked the same question to the outfit where I purchased the regulator, they, of course, recommended the DC to DC charger. I opted to follow Balmar's recommendation.
 
By the way, I am finding the Xantrex to be not terribly helpful now. It does provide me with total voltage (which my solar Blue Sky controller that is located directly beneath it at my chart table provides) and Amps going in and out which is useful, but that is really the only useful data it gives me. It's calculations for remaining life of the batteries is useless.
 
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