Charging Lithium Batteries on My Boat With an Alternator?
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- Опубликовано: 8 фев 2025
- "I have a Perkins 50 hp diesel engine on my boat," writes Gregory. "Would a Victron Orion-TR Smart 12/12-18 Amp Isolated DC-DC charger work well with a Balmar 100 Amp alternator to charge a 400 Amp Hour Dakota lithium battery bank?"
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If one assumes the external voltage regulator with an LFP profile, the house bank (Dakota Lithium) could be charged by the alternator and the Orion 12-12/18 could be used to charge the starter battery from the house bank. That way, the house bank gets all of the charge from the alternator and the Orion/starter batt is, at most, 18 amp load when switched on.
I think your answer is best though if the system only has a dumb internally regulated alternator (ie, no LFP charge profile). Definitely would want/need at least two 30 amp paralleled b2b chargers.
THANK YOU, Jeff for this great service to the boating community. I wish you had a Chesapeake Bay branch 😉
I agree with Jim, Throwing everything into the LPF's, alt, solar (if he has it, genny), and then going to the AGM - biggest to the smallest. And at the end of the day, the LFP's could charge / start the AGM.
Balmar has external controlers for lithium that have protection against open circuit. Assuming open circuit protection is the only reason to connect directly to a lead starter battery.
I was thinking exactly the same thing… bring all the juice directly to the lithiums, and then install the dc/dc to charge the starter…. Not sure if I’m missing something….
WARNING: Good lithium batteries like the Dakotas, have a BMS (battery management system) which will disconnect the batteries from the charging voltage when it decides they are full. This will create a current spike back into the alternator and fry the diodes. There are devices out there which will take that current spike instead of letting it get back to the alternator but they are for emergencies and not for frequent use. The best/easiest/safest way to charge lithium batteries from an alternator, in my opinion, is via a dc to dc charger. If there is a better way that is just as safe, I would love to hear about it.
A side note on current spikes, the same thing will happen on any battery being charged by an alternator if you turn the 1/2/both/off switch to off while the alternator is outputting current. This is why you should never cycle through the off setting while the engine is running.
Jeff, I recently watched one of your older videos where you predicted that in the future boats will have only DC power. Are we there yet? How would we be able to run air conditioners on DC power. This questions is for doing this in a 40 foot sailboat. I have watched many of your videos in the last 30 days. They are great and I have learned a lot. Thanks. Marcos
Hey there! I dont know if we are there yet 100% but I can say that CTM Marine does make a 12vdc 6,000 BTU AC. Looking forward to watching where they go with this. Hopefully they go to 24vdc to get the BTU’s in the 12-20 range.
Hi Jeff, love your videos, this is a little off topic, I have a 420 amp gel house bank and a 160amp alternator, I am planning to upgrade my charging system with external multi stage regulator and a Victron DC to DC charger, I see victron suggest to wire the starter battery to the input and the house bank to the output of the DC to DC charger. Someone told me I can hook up the house bank to the input and the starter to the output, what are the pros and cons for this setup?
Thanks
Mario Borg
I have wired systems as others have suggested, where the DC to DC charges the start bank, and all the charge sources feed the house bank including the alternator, Batteries with an external charge relay control like Victron and others (some are using CAN to control charge sources) are important when wiring in this way
Thanks for sharing Nick.
I recently added a pair of SOK 206AH LiFePo4 "marine" batteries to my boat to replace an existing 400ah FLA battery bank. The alternator is wired to a Victron Argo FET isolator (200A) with 3 outputs. One to the forward 4D bow thruster/windless battery, one to the 4D start battery, and finally one output to a Renogy 40A DC-DC charger( 12V-12V) with a LiFePo4 charging profile to charge the house bank. The alternator is an internally regulated 135A unit. So far it has worked very well. The alternator has different charging paths to both the Bow thruster and Start batteries in case the BMS(s) on the Lithium house bank shut down, so I am not worried about blowing up the alternator diodes. The DC-DC charger is capable of "waking up" a BMS that has shut down due to undercharging, etc.
On the charge side, I have a Magnum 2000W inverter charger with a 100A charging capacity. The battery manufacturer rates the batteries for a nominal 40A charge (each) so 80A total and a maximum charge rate of 50A (each) OR 100A total. I generally charge them at a combined 80A.
I did spend some time doing my homework, but am always open to constructive ideas. Is there anything I am missing on this system?
You seemed to have done your research.
What are your thoughts on the Renogy DCC50S, it’s a DC-DC charger with an MPPT which will output 50amps from either alternator or solar individually or split it 25/25 amps when connected to both. It has temperature compensation, over voltage, over current protection and a VSR, as well as complete data and programming with the optional $60 monitor display. The DCC50S costs only $260.
Sounds promising, but never tried this product before.
@@PacificYachtSystems ok, looks like imma try it out and report back 👍
Keep up the great content❗️
How did this work out for you? I am looking to install one in a Catalina 38
Jeff what I have done is added a FET to the alt system and made the house and starter system isolated from each other with their own shut off switch, I know what happens if the starter battery fails , well I have a spare trolling Deep cycle battery that I could use. I also have 350 watts of solar for the house and FET is used for the trolling bat.
Thanks for sharing Leo, much appreciated.
Why wouldn't you wire the alternator directly to the house bank and the DC/DC to the starter battery from the house bank?
I am projecting PV inverter for caravan, and I was wondering about putting alternator on inverter's PV input. As this inverter has only one PV input, I would put PV and rectified alternator input in series with optimizer diode. Peak Voltage of PV string is around 40 volts and and maximum of the inverter is 80 volts.
Hello Jeff,
I am in the process of replacing all of the AGM batteries on my current boat. I have two diesels running 80 amp Hitachi internally regulated alternators. I am going to an 8D lithium starting battery and 4 100 amp hour lithium house all in parallel, I also have a 80 amp hour generator start battery. With all of the batteries being lithium how can I protect the alternators from high voltage shutdown and losing power while underway?
I’m a heathen with no fancy this to that chargers. I simply have a decent programmable BMS set up to disconnect at 14v, no absorb as not needed at the sort of currents an alternator puts into batteries of the size I have and this voltage also gives some time for the balancing to operate as it is in the knee section of the charge curve. I have a parallel lead acid that protects the alternator and the several solar controllers which would have made lithium profiles into a nightmare. I leave all set to lead acid at 14.4v or over. I have a slightly longer wire than needed on the alternator which restricts the current a bit using about 0.4v drop at 100A this also gives a slight taper at the end of charge which suits the recommended charge profile of the cells I use.
Thanks for sharing.
Hi love your videos. I basically have the setup you described here. I have a 60 amp Sterling dc to dc charger but I’m finding the alternator appears to be working harder than I want. Could you do a video on how to setup the Balmar 614 to output lower for certain time period.
Be sure you use the alt temp sensor for the regulator
I am looking at installing Lithium house bank with a DC to DC charger to my AGM start battery. If the alternator is connected to the lithium house and the start battery through the DC to DC charger if the Lithium house did cut off, would not the house take up that "spike" through the DC to DC charger? Also, I was wondering what is keeping the DC to DC charger from attempting to charge the start battery when there is no charge current flowing to the house bank from any charge source? Is the resting voltage of the lithium high enough to keep the charge current flowing into the house at all times?
I've been wondering the same same thing. Also, there are devices to protect alternators if the BMS shuts down the lithium bank.
Hey Jeff! Love your work, Kelowna local here, who is trying to sort out the previous boat owners electrical mayhem.
We have dual engines, each with a 50 amp alternator. Each engine has its own dedicated starter battery. We are upgrading to 600ah of lithium for the house. We are adding two strings of solar and also have a GENSET for emergencies with its own battery. Currently there is 2 shore power lines In, and 2 separate 120VAC lines, one dedicated for Air conditioning, one for all other appliances. Air conditioning only works with shorepower line 1, or the GENSET on.
My plan is 600 ah Lithium/1200W solar charging/3kw inverter charger to be able to simplify to a 1 line smart charging system that is capable of continuously running the air conditioning that keeps my starter batteries fully charged first so i can always get home. I don't want to deal with 1, both, 2, off switches anymore.
Our plan to combine the starter batteries and house bank is VE dc to dc charger. Do I need one for each alternator and GENSET? Or do I use battery isolators before the starter batteries and then dc to dc charger from starter to house?
Best,
Norb
6047610654
You should consider installing dedicated DC to DC charging converters between each respective engine battery (port and stbd) and the lithium bank. The Generator alternator output or the generator battery, ideally should be used to recharge any other batteries onboard. Instead use the AC output of the generator to power battery chargers to charge your battery banks.
Here is an idea.
Charge the lithium battery directly from the alternator assuming programmable external regulator, and have the DC to DC charge the start battery.
That way you get full and direct usage of your 100 Amp alternator and can trickle charge your starter battery with the DC to DC that you have.
If the lithium battery shuts down for some reason the current will still see the DC to DC and be protected.
If you are still worried about protecting your alternator install a Sterling Alternator Protection Unit.
No need to parallel 2 or 3 DC to DC units, that's just more equipment to do the job at hand.
I didn't read any of the comments but now see I am not the original idea man.
Jeff, suggest that you edit the outdated video or people are going to watch it and buy unnecessary equipment
Jeff, Can you comment on using a Balmar alternator coupled with a MC-614 external regulator and a Balmar (or Sterling ) APD in directly charging a Lithium bank (Battleborn or Dakota Lithium)? If properly programmed, this seems to be a safe solution, however, you only discuss DC-DC charging. Can you please comment on the direct setup (with protections)? Thank you
I second this. I have looked at all of his videos and he doesn't touch on this. Especially now with the new dual purpose lithium start/ deep cycle batteries, this is a much bigger question now
Is it safe to mount the 12|12 30 victron dcdc charger in a gasoline engine room on a boat?
Agree, I have a 200AH and installed the 30amp Victron DCDC.
Hoping he installed 2 x 30amp.
Not running direct off alt like some said. That’s a warranty void right there.
It finally sunk ⬇️ in that a DCDC Charger, has an amp category 🙄 I just bought the device [for an eventual installation] solely on the proviso that it automates charging..
I’ll be on the market for a regulator too, Thanks 🙏 🤓Teåch 🍎
+ Sooo, 🔍🤔 a lithium can handle a large fast 💨 🏁 amperage, but NEVER exceed the battery’s storage ability, wherever that’s stated 🔍🤔
Okay Teåch 👨🏻💼🍎🤓👋
Exactly!
1 have house bank and no starter battery, house bank is 450 amp 12 volt, lead,
my engine a 6 cylinder ford Lehman diesel has a small 60 amp alternator.
my main recharge source is a three cylinder diesel genset 120volt 5.5 kw and it feeds a Mastervolt 3000 watt/160 amp battery charger set to charge lead.
if i upgrade to a larger lithium house bank will i have to change the alternator?
If you have a high output alternator controlled by an external regulator and want to charge both a start battery and a sizable house bank with a B2B charger using all the output of the alternator/regulator you paid a lot of money for, then it seems counterproductive to limit that output to 30A. Yes, you can connect 3, 4, 5, 6 or more B2B’s in parallel to get back the alternator output you already paid for; but remember they cost $225 each and 6AWG cable isn’t cheap, not to mention the space needed to mount all of this equipment. I’m planning to keep the alternator on the house side; meaning my alternator output will go directly to the house bank via the positive un-switched bus. The B2B input will be connected to the positive un-switched bus (alternator) and the B2B output will connect to the start battery positive post to charge it. The only thing I have no answer for yet is if the B2B start-up voltage can be set low enough (via the Victron app) to insure the start battery starts getting charged soon after engine start-up even if the house bank is at an extremely low voltage. My back-up plan is to utilize the remoter on/off function to install a switch and turn the B2B on/off manually. I have been trying for weeks now to get answers form my local Victron Dealers but have failed to receive any feedback. Victron does not provide support directly, which is very unfortunate. Good Luck and Happy Days...
if you have the victron connect app, there is a demo library in the menu to see and test the settings of any victron product. So you can see the ranges and settings of products before you buy them.
You can also set it up so it turns on with the key, instead of a manual swtich.
the issue with going direct to the lithuim house bank is if the BMS opens while charging, you may blow up the alternator. This needs to be taken into consideration when planing the layout.
@@PacificYachtSystems Once again, you guys are AWESOME!
I have a 900AH lithium battery bank and two 100 amp alternators on my Crusader 454's. Both engines are started by a single lead acid starter battery. One of the alternators is hooked up to a battery isolator which also is attached to my house bank. Is this setup safe for my alternators? I heard lithium can overheat alternators, but so far they don't seem to draw any power whatsoever from the alternator.
How can I charge lithium batteries off of my mercury outboard?
Lead starting battery, 2-12v lithium batteries for my 24v trolling motor. I installed a minnkota alternator 2 bank mk2dc to charge the old lead trolling motor batteries. Can I install 1 dc-dc unit after the alternator to chsrge 2 lithium?
Can you have one of these DC to DC chargers connecting your Lithium Batteries to your alternator in addition to having a separate DC to DC charger Charing your lithium battery bank from you lead acid start battery (both running at the same time) ??
The dc to dc charger is an imperfect method if you have both ac and dc coming off the same house lithium bank. I have 600 ah lithium bank being charged underway by 30amp dc to dc charger off the starter battery. More is going out than coming in while underway. This means that after 10 hours or so of running my house dc will die. I need about 75 amps comin in to stay neutral. I have two 130 amp alternators on my big diesels but have tried to avoid any complications with them. Ultimately I think I need to get alternator regulators and skip the dcdc charger. Hope this helps you to avoid this problem, and would take any advice
You can buy bigger dc to dc chargers or install a few of them. I would definitely have at least one from each engine. that would give you 60a. adding 2 to each engine will give you 120a.
Moving the alts to the lithuim bank with an external regulator still doesn't fix the bms opening issue. Unless you have an external bms. four 30a orions is probably around the same price as 2 balmar regulators + alt temp sensors + modifying the alts
@@PacificYachtSystems thanks so much Jeff for the reply! You just backed me down from “the big alternator project”. I’ve considered the extra dc/dc, but hesitated because it will require heavier gauge wire running from the chargers to the bank. But maybe that’s the simplest thing to do. Actually the cleanest option would be to just put back in a separate house dc bank with agm charged direct from the alternators, but lack of space gets in the way…. Thanks again
Hi Jeff,
I'm in the process of planning the same upgrade (educating ;-) )
What are situations that needs isolated and non-isolated dc-dc charger ?
Can you explain with cabling diagram ?
Thank you
On a boat with all grounds /negs tied together, an isolated DC to DC is pointless. You would only use an isolated where it is needed to have 2 seperate systems, a towable RV comes to mind perhaps?
@@nicholaskeur Thanks Nick !
Just wondering: do these DC-DC chargers operate only when a charging voltage is detected, or will they continue to move energy from the starter battery to the house battery even after the charging source is removed (or is the desired behaviour programmable)?
Yes, They only work when charging is detected
Great video. I am planning to install 100 Ah 24 v lition battery on my boat which is itended to power Minn Kota trolling engine. Cn solar pannel successfully change that battery? The boat is 6.7 m rib with hardtop . Thanks
The size of your solar array will decide how long it takes to recharge a 100 Ah 24 V lithium battery. For example, a 200 watt solar array, might give you you 25 Ah at 24V of recharging in a day.
hi guys, i have an AGM starter battery and deep cycle lead batteries that is want to replace by a 410ah lifepo4 battery with bms..
at the moment , i have both batterybanks connected to my alternator ( 75amps) by a diode bridge.
as i dont want to fry my alternator, i am wondering if i can put a dc to dc charger ( like a victron 50amps dc to dc ) between the diode bridge and the lifepo4 battery?
instead of placing the dc to dc charger between the starter battery and the house battery??
Thanks
Glad our content resonated with you.
Great video. I am planning on removing my 8G4D's and putting in a 400aH LiFePO4 for my house bank. I have a solar panels on board with a MPPT comptroller but my concern is how the stock 60a alternator that came with my Yanmar 3GM30F is going to interact with the new battery. Should I upgrade the alternator or look for a smart regulator?
When going to Lithium batteries, you should definitely consider a compatible alternator and external regulator combo .
@@PacificYachtSystems thanks. Any recommendations for ones compatible with a Yanmar 3GM30F?
Jeff, Can I put two Victron 30 amp Orion DC to DC chargers in my sailboat if I only have a 60 amp alternator? 4 Battleborn Batteries, one Optima Blue Top starting battery. No solar yet, so alternator and ac battery charger are currently only recharging sources. Alternator is only away from dock source. I have very limited funds, otherwise I would be buying a new high output alternator as well. That purchase will eventually happen.
Jeff thanks for all the info. I am adding a lithium and victron multiplus 2k this spring. I have twin outboards, was planing on the Orion TR smart 12/12 -30. What is the possibility of using an A/B switch from both start batteries in an effort to have the option of running either engine, equalizing engine hours. Is this a worth while (or dumb) or just install 2 DC/DC Converters.
Going with dedicated DC to DC charging converters from each engine battery to your new Lithium battery is our standard approach.
Hi Jeff! What if he had a dual alternator set up? One for the engine battery and another for the leisure battery bank? What would he need to put in between the alternator and the lithium batteries to stop the batteries drawing too much and overheating the alternator? If he has smart lithium batteries with inbuilt bms will they prevent that without anything else in between?
You would want an external regulator on the service alternator. IE a Balmar mc 614 with an alternator temp sensor that will throttle back the alt when it gets hot. You can also program it so it will never run at max power but say only at 90%. They will be programmable for the correct voltages as well. It's really the only way to correctly directly connect an alternator to a lithium bank.
The engine alternator could be the standard internal reg alternator.
Hello, is there a big difference between tinned copper and nickel platted brass in bus bar performance and reliability?
Hmmm... never did a comparison test, but we mostly use tinned copper.
Hi Jeff, you mentioned you have three Orion 30amps dc/dc in parallel. Just out of curiosity, what alt you have installed? 120amp, perhaps??
Yep, good suggestion.
Nice opening for 'Holi' celebration.
good one.
What about connecting the alternator to the 400amp-hour battery and using the charger for this starter battery.
WARNING: Good lithium batteries like the Dakotas, have a BMS (battery management system) which will disconnect the batteries from the charging voltage when it decides they are full. This will create a current spike back into the alternator and fry the diodes. There are devices out there which will take that current spike instead of letting it get back to the alternator but they are for emergencies and not for frequent use. The best/easiest/safest way to charge lithium batteries from an alternator, in my opinion, is via a dc to dc charger. If there is a better way that is just as safe, I would love to hear about it.
Thanks for sharing Mario.
Hey, i dont understand why this 12:12 30 isolated dc to d charher device wouldnt drain the start batter? How does it know to stop charging when the alternator is off?
Hi Jeff, my question is I bought a dakota lithium 12v 60AH to cranking my yamaha 115 outboard motor and run my fish finder. After installing everything work fine but some how I can't speed when my RPM hit 4000 it automatically slow down my yamaha motor and shut off my finder..any help.
I'm betting the BMS opens when you start and you have no battery while running the boat, only the alternator output. but it's hard to say. are you using the DL+ cranking battery or the regular one?
If you connect the alternator to the lithium batteries and have the dc to dc charger to the agm, would the alternator have a problem if the lithium batteries disconnect via the bms? Would this be a case for isolated or non-isolated charger in the circuit?
Your concern is valid, the DC to DC converter might help to avoid a sudden disconnected BMS on your lithium, but i'm not 100% sure it would work all the time. Hence, why some boaters consider the battery isolator instead of the DC to DC charging converter.
@@PacificYachtSystems Wouldn't that create a problem with the 2 different charging profiles?
I installed a lithium (I believe 8AH) battery in my motorcycle. It works great. Do they make a lithium that I can use in my tender (40hp Yamaha 4 stroke motor) that would replace an optima blue top? I’ve been waiting and checking for years. I would like 100ah if possible and charge straight from the outboard. Thanks
Not familiar with a good starting Lithium battery for boats... anyone else can make a recommendation.
Hello. I have a 75AH AGM battrry and I want to change it to lithium. Will I be able to just replace it with current battery? As I heared lithium battery draws much higher amps to charge and specially with alternator on low RPM can it blow up alternator? How this replacement can be done? I will appreciate reply.
Going to Lithium has many implications, from max current, to recharging with a charger or an alternator, stay tune for more videos on this topic.
Have anyone tryed to control the field with a simple thermistor ?
As long as one can continuously change the field voltage so to regulate the alternator output.
Wouldn't it depend on how you're using your boat?
What is the deal with this video ? Like a 2 tier recording from the moon ?? Never seen you do one like this Jeff, hard to comprehend what your saying
Hi Chris, really sorry... let me look into this.