Lithium battery house battery charging/alternator overload?

Ken O

Ken O

Member
I am upgrading the house battery to a 100 Ah lithium battery (crew member with CPAP needs). The battery will be charged via a Redarc DC-DC charger (BCDC1225D). This charger will also accept solar input, but please ignore that for now, as it will not handle the whole load all the time, so much or the recharging work will fall on the alternator.

Therefore, question: My Honda 90 puts out about 16 amps. If the battery is down, say 30-40 amps, will the alternator try to handle this whole load, or might the start battery act as a buffer and ease the load on the alternator?

There is a lot written in various forums about people killing their alternators from overload, but these are mostly off-road hotrodders running 150 amps of lights and stereos from one alternator and one battery. Our basic electrical load will be small, as we don't even have a refridge.

Thanks for your thoughts.
 
I was in the same situation as you....my alternators/stator charges 10 amps. Because of this, when I plopped the LIFEPO4 house battery in, I struggled to even put a DC to DC charger in the dang thing since the minimum setting on the charger they recommended was way more than the rated output of my alternator. The Relion rep I was working verified that even bothering was futile once he understood the situation. Anyway....I bet your alternator/stator is charging full tilt all the time pretty much just to run minimal electronics on your boat. So, I'm basically stuck with switching the batteries to "all" and hoping for the best, which I am reluctant to do because of the knowledge/experience given by our fellow C-Brats, and charging at home because my "charging" system is so underpowered. I really wish mine had some kind of bluetooth app that allowed me to tailor the charging algorithm for my particular situation. I'm following.....good question :-)

As a side note.....I don't think the LIFEPO4 will get much of any charge with your 16 amp alternator/stator no matter what you do.
 
The short answer is "the start battery will act as a buffer"

T.R. B is correct: I would be more concerned with the charging system's output and your start battery than damaging the OB's charging system. The DC-DC charger is going to try and pull around 20 amps out when it senses your house battery is not full. If you have less than 20 going in to your start battery, you will drain the start battery. I'm assuming 16 amps is the rated maximum of your OB, so most of the time you will have less than this available.

If you want to stick with DC-DC charging, you may want to look into turning the DC-DC charger on and off manually to make sure that your start battery is recovered by the time you arrive at your destination. A house battery monitor and a volt meter on your start battery would help you decide when to charge. This will not quickly recharge your house battery; you will have to do the math on if this is sustainable. I don't think there's anything you can configure on the Redarc to turn on and off for you automatically in the way I am describing: The low voltage cutoff likely isn't going to work to save your start battery when the outboard is trying to charge the start battery.

Just for the record, my setup is very similar, but my OB is rated at 40 amps max output. I do not have a CPAP but I do have refrigeration; I have no problems managing power with a similar setup but more charging available.
 
That's a comforting thought--we can live with a battery system that will take longer to charge, as long as it doesn't hurt the alternator.

I gave a simplified version in my original post to focus on the alternator question, but it will be easy for us to monitor and to shut off the Redarc charger as it will be controlled by a relay connected to the ignition circuit. We will also have a smaller DC-DC charger rigged to top off the start battery from solar, and the relay switches between the 2 chargers. If I put a switch in the ignition circuit feed to the relay, I can turn off the bigger DC-DC charger if I see an overload.

I also have 220 watts of solar on the roof to help out.

Thanks for the info!
 
Well after much searching, thank god for Utube, I settled on a Weize12.8 volt-100AH battery.,https://www.amazon.com/dp/B09F2LLMY3?psc=1...
, After chargingg up t he battery I installed it in the boat. direct swap, and ran it for several hours starting and stoping. It was peforming properly. Charging at 14+ volts. Got my Grand sons over and headed out for the day. As soon as I was above 2,000 rpm my GPS said it was over voltage and shut down! the voltmeter was all the way of to the right, only reads to 16 volts. Reduced speed to idle and the Voltmeter went back to 14.4 volts. I turned the GPS back on and its voltage was 13.8, same as the volt meter. I increased the RPM to 2000 and the GPS went into "over voltage mode" and shut down. The voltage was showing on its screen at 16.9. I idled back to the dock and tied up. Shut the engine off and restared it several times. No problems!!! I went home and got one of my older AGM batteries, swapped them over and went again without any issues for the rest of the day. What am I doing wrong????? The LIPO batter allows over charging, the AGM doesn't.The engine is a 2004 BF 40 Honda.
4d
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Edited
 
What is controlling the charging? The Honda is designed to charge lead-acid batteries. Lithium needs a different profile, and, I think, lower max voltage. The 16.9 volts you saw could be from the voltage regulator or battery reacting badly to the wrong charging profile.
 
rmullette":2o70dffv said:
Well after much searching, thank god for Utube, I settled on a Weize12.8 volt-100AH battery.,https://www.amazon.com/dp/B09F2LLMY3?psc=1...
, After chargingg up t he battery I installed it in the boat. direct swap, and ran it for several hours starting and stoping. It was peforming properly. Charging at 14+ volts. Got my Grand sons over and headed out for the day. As soon as I was above 2,000 rpm my GPS said it was over voltage and shut down! the voltmeter was all the way of to the right, only reads to 16 volts. Reduced speed to idle and the Voltmeter went back to 14.4 volts. I turned the GPS back on and its voltage was 13.8, same as the volt meter. I increased the RPM to 2000 and the GPS went into "over voltage mode" and shut down. The voltage was showing on its screen at 16.9. I idled back to the dock and tied up. Shut the engine off and restared it several times. No problems!!! I went home and got one of my older AGM batteries, swapped them over and went again without any issues for the rest of the day. What am I doing wrong????? The LIPO batter allows over charging, the AGM doesn't.The engine is a 2004 BF 40 Honda.
4d
Reply
Edited
Click to expand...

I will tell you that I am going to be very critical for a very good reason; your and anyone else who read's this safety! You may have looked at Will Prowse's review of this cheap Chinese battery (His review is very good)

This battery is not rated for engine starting.. Any LiFePO4 battery needs a specific charging profile. The Honda 40 has a semi regulated 10 amp output of its charging output. This is not suitable for this LiFe battery!

Your system needs to have a battery to battery charger with a lead acid engine starting battery. The available battery to battery chargers mostly start at 18 to 20 amps. There needs to be a shut off switch before the battery to battery charger, and a fuse after the switch. There needs to be a fuse on the output of the b to b charger and at the input to the battery, unless there is about a foot or two between the two. If there was to be a short of any wire from that LiFe battery, hang on for fire works and most likely a fire.

On the output of the LiFe battery there needs to be a fuse, and a switch rated for that battery's output. The cables have to be sized for any load on the LiFe battery

A 120 V AC main's charger with LiFe profile needs to be the charging source for the 100 amp hour battery. 10 amps works well, and in the Chinese market there are several in-expensive batteries which work well.d

Here is a DC to DC charger which may work for your application. But you still have to have the lead acid (or AGM) battery for a start battery.. This is not a marine charger and I would only use it with a smart shunt to monitor your battery. (Smart shunt or meter is almost essential when using LiFe battery on your boat.)

What will happen if you use the system as I understand it. Most likely will damage the motor's charging circuit. May destroy it. There remains risk of fire.

I put in a "Chinese" 500 amp switch on my 200 amp hour Battle Born system on the C Dory 25. The first time I used the 2000 watt Multiplus inverter, that switch disintegrated, with attendant smoke and fire. I was using the system to run my microwave, probably a 3000 watt surge. Means still under the rated amperage of the switch...lesson: Chinese stuff is rarely premium, and may be way over rated. replaced with US made 500 amp switch and no more issues.

That is the short answer.

I did make a system I keep in our SUV to keep frozen food when traveling. A 100 Amp Hr LiFe battery, a 18 amp Battery to Battery charger. A monitor of input and output, voltage, amps and State of charge. A battery switch to output and proper fusing on all of the circuits. A 10 AMP Mains 120 Volt charger. All of this lives in a group 31 battery box, and the out put goes to a plug on a 12 volt chest freezer.

I hook this up directly to the vehicles start battery (fuse right there on + side) I use rings, and put on posts, no clamps used.
 
rmullette, your outboard's charging is not regulated. The outboard's charging system is going to go over-voltage because the LiFe4PO charging goes "over" voltage (14.something depending) compared to a traditional battery. This is not a problem related to batteries made in one particular country, or one particular brand. This thread was a discussion of using LiFe4PO batteries for house batteries. You need to keep your traditional battery as your start battery. As others have implied, I would also suggest that you may need to do more research before integrating your LiFe4PO battery even as a house battery on your boat.

It's worth noting that Merc and others now endorse (some) LiFe4PO batteries to be used as start batteries for some outboards, but your older outboard and generic battery are not going to be on any list.

If you decide to use your LiFe4PO as a house battery: I like the DC-DC charger that Thataway shared; I am using a similar-cost unit, but my only options are 20A and 10A; the finer control of the Powerwerx would be nice, especially for your older outboard. 8A seems like a nice safe upper limit.

In 2023, sticking with traditional batteries and battery-switches is still the easiest, most reliable, and least expensive solution. :D
 
In 2023, sticking with traditional batteries and battery-switches is still the easiest, most reliable, and least expensive solution.
Click to expand...

I support that comment entirely. I see all these posts on the various batteries, and yet my two group 29 house batteries and one group 24 starting battery, all of which are the lead acid marine deep cycle and starting batteries, work great, and last easily 4 or 5 years. I upgraded the original battery charger to a nice 20 or 30 amp master volt charger, and just recently installed 200 watts of solar. I routinely run a freezer, refrigerator, cpap, fan and lights on these batteries day and night. Usually the outboard charges everything back up while running during the day. Otherwise if in a slip or on the hook during the day, the solar or little Honda generator brings the batteries back up to 100%. Easy Peazy! :) Colby
 
This is why the hassle of a small 100Ah LiFePo4 house battery is worth it for me on a 22; that's a lot of weight!
Click to expand...

Understood. On my 22 I just had one group 27 house battery and one group 24 starting battery. Of course I didn't have the frig. But had everything else. :) But less weight is good. Colby
 
I appreciate all the recent threads concerning the addition of solar charging options. It has been a great education. Our largest power demand is the Engel 14 refer/freezer. If we are at anchor more than 24 hrs we are in need of charging with the alternator on the Honda 90, even with 3- 85ah AGM house batteries. Solar charging makes sense as I don’t want to pack a generator. I understand there are issues with charging lithium batteries with the Honda 90 alternator. My question is, what do the experts think about using a portable system like the Jackery system? I talked to a couple sailboat owners this summer who were sold on their systems.

https://www.jackery.com/products/jacker ... gLwDvD_BwE

An advantage for me is that it could be used on the boat, with our pickup camper or at home when the power is out. The portable panels can more efficiently track the sun throughout the day vs. fixed mounted panels. Using the lithium battery to power the Engel cooler is isolated from boat’s electrical system. This avoids the potential problems with lithium and the Honda 90 alternator. I’m open to suggestions. Thanks in advance. Ken
 
kennharriet":i58k7cuw said:
My question is, what do the experts think about using a portable system like the Jackery system?
Click to expand...

I have a Bluetti AC200Max (2048Wh) + portable panels and all the extras. I purchased it after good success with a smaller power bank on a prior sailboat.

I planned on using it on the 22, but it wasn't for me. I still recommend them!

They work GREAT to just run a small refrigerator as a stand-alone system that gets recharged at home, or maybe topped up with a portable panel on a dock.

If you have a need for a completely independent system, don't want to do any wiring, have the room, or just want to bring a little extra power on board, I would suggest it. Make sure the weight and dimensions work for you; the bigger units like the AC200Max are a lot to move around.

If you want to run the boat's standard house loads (VHF, lights, trim tabs, etc) from a power-bank, you will need to think about how you will integrate it: The current limits, the required connectors, the "boot up time", the on-unit switches, and what you will do if there is a problem. If you want to utilize the built in DC-DC charging, that may add a little more integration complexity as well.

For me, the integration and practical details meant a "normal" house battery arrangement made more sense. If my AC200Max were a little lighter and smaller, maybe I'd feel differently.
 
thataway":3eijwonp said:
rmullette":3eijwonp said:
Well after much searching, thank god for Utube, I settled on a Weize12.8 volt-100AH battery.,https://www.amazon.com/dp/B09F2LLMY3?psc=1...
, After chargingg up t he battery I installed it in the boat. direct swap, and ran it for several hours starting and stoping. It was peforming properly. Charging at 14+ volts. Got my Grand sons over and headed out for the day. As soon as I was above 2,000 rpm my GPS said it was over voltage and shut down! the voltmeter was all the way of to the right, only reads to 16 volts. Reduced speed to idle and the Voltmeter went back to 14.4 volts. I turned the GPS back on and its voltage was 13.8, same as the volt meter. I increased the RPM to 2000 and the GPS went into "over voltage mode" and shut down. The voltage was showing on its screen at 16.9. I idled back to the dock and tied up. Shut the engine off and restared it several times. No problems!!! I went home and got one of my older AGM batteries, swapped them over and went again without any issues for the rest of the day. What am I doing wrong????? The LIPO batter allows over charging, the AGM doesn't.The engine is a 2004 BF 40 Honda.
4d
Reply
Edited
Click to expand...

I will tell you that I am going to be very critical for a very good reason; your and anyone else who read's this safety! You may have looked at Will Prowse's review of this cheap Chinese battery (His review is very good)

This battery is not rated for engine starting.. Any LiFePO4 battery needs a specific charging profile. The Honda 40 has a semi regulated 10 amp output of its charging output. This is not suitable for this LiFe battery!

Your system needs to have a battery to battery charger with a lead acid engine starting battery. The available battery to battery chargers mostly start at 18 to 20 amps. There needs to be a shut off switch before the battery to battery charger, and a fuse after the switch. There needs to be a fuse on the output of the b to b charger and at the input to the battery, unless there is about a foot or two between the two. If there was to be a short of any wire from that LiFe battery, hang on for fire works and most likely a fire.

On the output of the LiFe battery there needs to be a fuse, and a switch rated for that battery's output. The cables have to be sized for any load on the LiFe battery

A 120 V AC main's charger with LiFe profile needs to be the charging source for the 100 amp hour battery. 10 amps works well, and in the Chinese market there are several in-expensive batteries which work well.d

Here is a DC to DC charger which may work for your application. But you still have to have the lead acid (or AGM) battery for a start battery.. This is not a marine charger and I would only use it with a smart shunt to monitor your battery. (Smart shunt or meter is almost essential when using LiFe battery on your boat.)

What will happen if you use the system as I understand it. Most likely will damage the motor's charging circuit. May destroy it. There remains risk of fire.

I put in a "Chinese" 500 amp switch on my 200 amp hour Battle Born system on the C Dory 25. The first time I used the 2000 watt Multiplus inverter, that switch disintegrated, with attendant smoke and fire. I was using the system to run my microwave, probably a 3000 watt surge. Means still under the rated amperage of the switch...lesson: Chinese stuff is rarely premium, and may be way over rated. replaced with US made 500 amp switch and no more issues.

That is the short answer.

I did make a system I keep in our SUV to keep frozen food when traveling. A 100 Amp Hr LiFe battery, a 18 amp Battery to Battery charger. A monitor of input and output, voltage, amps and State of charge. A battery switch to output and proper fusing on all of the circuits. A 10 AMP Mains 120 Volt charger. All of this lives in a group 31 battery box, and the out put goes to a plug on a 12 volt chest freezer.

I hook this up directly to the vehicles start battery (fuse right there on + side) I use rings, and put on posts, no clamps used.
Click to expand...


Bob,

I'm getting ready to add a 100AH lithium to my house bank. Can you take a moment to explain why a charger like the Powerwerx is better than the Yandina Combiner? https://smartshoremarine.com/products/b ... -batteries

From what I read on the Powerwerx, it charges at 14.6, which is about what a normal alternator puts out. I'm trying to find out why the charger is better than the combiner, aside from cost. The Powerwerx is about half of the Combiner. Both quite inexpensive in the big scheme of boats.

Thank you!

Rob
 
Bob,

I'm getting ready to add a 100AH lithium to my house bank. Can you take a moment to explain why a charger like the Powerwerx is better than the Yandina Combiner? https://smartshoremarine.com/products/b ... -batteries

From what I read on the Powerwerx, it charges at 14.6, which is about what a normal alternator puts out. I'm trying to find out why the charger is better than the combiner, aside from cost. The Powerwerx is about half of the Combiner. Both quite inexpensive in the big scheme of boats.

Thank you! Rob
Click to expand...

Rob, reading the manual for this combiner, it appears to be a combiner, There is no circuit diagram. Unfortunately Yandina passed on a couple of years ago, so we cannot ask her. There are several problems with direct combiners and the primary one is they just combine the two batteries, something you don't do with Li and other (FLA or AGM) because of the voltage difference. LiFePO4 floats at 13.6, and upon connection there can be a flood of current into the "start" battery. If there are blocking diodes, (generally would decrease the voltage) then it would work, if this combiner was profiled for charging the Li battery.

If Li is "added" to house bank of FLA or AGM, you have a huge imbalance and may have battery destroying inrush current to the non Li battery. A liFePO4 battery or bank must be isolated from a FLA house bank. For example on the C Dory 25, the Li bank of 200 amp hours was only for the two refrigeration units, and the inverter. Other house loads were still on FLA batteries. There was a way to cross connect, but in that case the Li battery and FLA still would not combine because of safeties.

Your situation is entirely different than the C Dory with a 40 hp outboard and a 10 or. so "alternator" output. You have two Yamaha 150s with 35 amps output per outboard. In your case I would use a Victron or Pro Promariner or Sterling (the same) battery to battery charger. The Sterling allows user programing. The 150 Honda puts out somewhere between 44 and 47 amps. I used the 30 amp Sterling Battery to Battery charger. You probably could get away with that. Definately, if you combined the starting batteries and charging from both engines to the starting battery which the B to B charger is attached. There are several ways that could be configured.

For the portable unit I chose the Victron Orion 12-12-18, which is 18 amps B to B charger. The reason is that we normally would be driving 8 to 10 hours on long trips, and that is plenty of power to recharge, plus the SUV has a fair demand for the electronics onboard. Did not want to overheat the alternator. There is also a 30 amp Victron 12-12-30 charger. I see that Renology has a 20 amp B to B charger. I would use the Orion. 18 amp instead of the Renology.

Always good practice to have a negative shunt meter when using the Li batteries. That way, you can measure amps in, amps out, voltage and state of charge.
Victron smart shunt (blue tooth to your smart phone) or the gauges with or with out blue tooth (702 without, 712 With blue tooth).
 
rmullette":n2wappjn said:
Well after much searching, thank god for Utube, I settled on a Weize12.8 volt-100AH battery.,https://www.amazon.com/dp/B09F2LLMY3?psc=1...
, After chargingg up t he battery I installed it in the boat. direct swap, and ran it for several hours starting and stoping. It was peforming properly. Charging at 14+ volts. Got my Grand sons over and headed out for the day. As soon as I was above 2,000 rpm my GPS said it was over voltage and shut down! the voltmeter was all the way of to the right, only reads to 16 volts. Reduced speed to idle and the Voltmeter went back to 14.4 volts. I turned the GPS back on and its voltage was 13.8, same as the volt meter. I increased the RPM to 2000 and the GPS went into "over voltage mode" and shut down. The voltage was showing on its screen at 16.9. I idled back to the dock and tied up. Shut the engine off and restared it several times. No problems!!! I went home and got one of my older AGM batteries, swapped them over and went again without any issues for the rest of the day. What am I doing wrong????? The LIPO batter allows over charging, the AGM doesn't.The engine is a 2004 BF 40 Honda.
4d
Reply
Edited
Click to expand...

I strongly suspect this is because your battery BMS shut itself off because the battery was charged. And then, there is not any place for the volts and amps to go that your outboard is producing. This means you were essentially running your outboard without a battery at all creating a feedback type of loop - a very bad thing BTW where the voltage just builds and builds. A couples of folks have implied (I think) this is because it's an old Honda 40 "alternator", which really isn't an alternator all, but really a stator with a rectifier bridge...and because it uses earth magnets instead of electro magnets like a proper alternator does, it really can't turn itself all the way off. I'm not saying they're wrong...but that is the reason why they're right. However, because it's an old stator/rectifier system, it's probably why it still works today....an alternator probably would given up the ghost during your mishap.

Anyway, generally speaking, LIFEPO4 batteries are not starting batteries as the others have noted. Keep your new battery and use it for a house battery only. It's proper to isolate it from the FLA batteries because it will bleed its voltage into your starting battery and vise versa without any way of knowing or control....not great. I charge mine at home, but can switch the house to a starting battery if needed.
 
I apologize for not getting back,but I am in the process of accumulating a variety of reccomended, and self sourced,chargers/controllers etc etc etc. and when i get them in I will work out a system. I have always been an early adopter, and I someone tells me "I can't do that" the gauntlet is thrown! I still don't know why "everyone" says you need a wet 12 volt for starting and house battery. I have started my BF40 at least 20 times withot any issue. My BF40 is not a large engine and its starting requirements are minimal. But I would suggest that its consistant with what a lot of people use. The ability to have a lightweight battery system with twice the draw -great for trolling motors- is obvious.
I have assorted smart chargers/controllers/shunts/power sources/meters/lipo batteries/solar panels etc, etc, etc!
The weakness that I need to address is controlling the power flow from the outboard to the battery. Currently that is a, non adjustable, controller/rectifier.
There is not a soul on earth that can convince me that they can't make one to address the needs of a LIPO battery. IT IS THE FUTURE!!!!!
https://www.amazon.com/Powerwerx-DCDC-8 ... r_hp_atf_m

Has anyone actuall used it???
I have a 12V to 12v 30 amp for my solar panel.
Any way -onward and upwards.
Both my outboardd and batterare still OK!!!!


This forum recomends this;
 
rmullette":1a1835pr said:
I apologize for not getting back,but I am in the process of accumulating a variety of reccomended, and self sourced,chargers/controllers etc etc etc. and when i get them in I will work out a system. I have always been an early adopter, and I someone tells me "I can't do that" the gauntlet is thrown! I still don't know why "everyone" says you need a wet 12 volt for starting and house battery. I have started my BF40 at least 20 times withot any issue. My BF40 is not a large engine and its starting requirements are minimal. But I would suggest that its consistant with what a lot of people use. The ability to have a lightweight battery system with twice the draw -great for trolling motors- is obvious.
I have assorted smart chargers/controllers/shunts/power sources/meters/lipo batteries/solar panels etc, etc, etc!
The weakness that I need to address is controlling the power flow from the outboard to the battery. Currently that is a, non adjustable, controller/rectifier.
There is not a soul on earth that can convince me that they can't make one to address the needs of a LIPO battery. IT IS THE FUTURE!!!!!
https://www.amazon.com/Powerwerx-DCDC-8 ... r_hp_atf_m

Has anyone actuall used it???
I have a 12V to 12v 30 amp for my solar panel.
Any way -onward and upwards.
Both my outboardd and batterare still OK!!!!


This forum recomends this;
Click to expand...

Not using them as a starting battery is a general recommendation from the engineers responsible for designing the battery. Will they start stuff? Yeah, as long as they BMS doesn't sense a short circuit and shut off the power. The little outboards don't draw much so it's inside its programmed parameters of the BMS and it worked in your case. But then then there is the over voltage condition you illustrated once your battery BMS terminated the connection with outboard due to the over voltage condition. Are there workarounds? I suspect so. Worth it? Well that is just one person's opinion, but it wouldn't be to me since the FLA is not very expensive or that much heavier.
 
T.R. Bauer":36rmg7jx said:
...
Anyway, generally speaking, LIFEPO4 batteries are not starting batteries as the others have noted. Keep your new battery and use it for a house battery only. It's proper to isolate it from the FLA batteries because it will bleed its voltage into your starting battery and vise versa without any way of knowing or control....not great. I charge mine at home, but can switch the house to a starting battery if needed.
Click to expand...

Couldn't you put a diode between the house (FLA) and the Li battery? Current could then only flow into the Li battery from the house batt, but not the other way around.
 
ssobol":32po3s5p said:
Couldn't you put a diode between the house (FLA) and the Li battery? Current could then only flow into the Li battery from the house batt, but not the other way around.
Click to expand...

Yes, but the voltage drop would be an issue. The Li battery floats at about 13.6 Volts. People seriously UNDER estimate how violent and depraved people become without rule of law It needs the higher voltage to charge. The nominal voltage of a IiFePO$ is 3.2volts. 13,6 for the 12V version, Fully charged voltage 14.6 volts.
 
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