Lithium Battery Charging with an Alternator

Lithium Battery Charging with an Alternator

Hello, how you doing? Thanks very much for
watching. Tomorrow here in the United Kingdom is a bank holiday but you wouldn’t think it.
Because the sheer mention of a holiday here, and it usually throws it down with rain. But for the last couple of days we’ve been
baking in fantastic sun, all day long and every morning, I’ve been waking up to my lithium
batteries 100% full, which is fantastic. But of course, every day isn’t as sunny as
this. So another way of charging your lithium batteries, or lead acid batteries or AGM batteries
or whatever you have on a narrowboat, is with an alternator, and that’s what today’s episode
is all about. The engine on my narrowboat has two alternators.
A 75 amp for the starter battery and bow thruster and a larger 175 amp for the leisure batteries. In my engine bay is the original large wooden
box to contain up to 5 batteries. As I have my new lithium’s inside, in a kitchen cupboard,
I wanted to sort the jumble of wires out and reduce the size of the box. After removing all the cables, switches and
relays I dismantled the grey box and disposed of it. I cut a new piece of plywood to fit
the two brackets that were welded into the engine bay. I decided to use two plastic
battery boxes with lids. This will keep the batteries and their terminals clean and give
me a lot more space to work with. Both batteries go through mega fuses and isolator
switches. The negative from the alternator protect battery goes through a Victron BMV
712 battery monitor shunt before joining to to the main negative bus bar. I’ve protected
both the shunt and the bus bar with Blue Sea MaxiBus Insulating Covers. The negative for both alternators is the engine
itself. The engine and the negative bus bar are connected to the steel hull via one connection.
Unlike a vehicle, it’s highly recommended to not use the hull as the return negative.
All the items onboard should, on a new install, use two wires, positive flow and negative
return. The 175 amp alternator has two feeds from its
positive connection. One goes to the isolation switch for the alternator protect battery.
The other along with a negative from the bus bar are protected in plastic corrugated conduit,
through the bulkhead and into my lithium cupboard. The positive connects to a fuse
on the bus bar. Alternators, although regulated to a certain
degree can treat lithium batteries a little harshly. Lithium’s can take a much higher
charge current and for longer and that has an effect on the alternator. The recommended charge amperage for each of
my 100 amp hour batteries is at, or below 50 amps. Although you can throw 300 amps at them
and they will charge, I wanted to look after my new lithium batteries as well as my alternator. After a lot of testing I’ve decided to use
a Victron BMS 12/200. It’s normally used as a battery management system but after a bit
of digging I discovered this PDF document. With the use of the Alternator control cable,
it ignores the battery management system part of the unit and instead performs two key functions
that I was looking for. I can regulate the charge current from the
alternator with the value of a mega fuse. The charge value is around 80% of the fuses
value and I can go as low as 40 amps and as high as 200 amps. I can also use the BMS 12/200 to cut the alternator
charge source, just like the battery protect can for the solar MPPT controller. The negative
from the engine bay connects to the far left terminal of the BMS 12/200. It goes via the
fuse and there is a short length of 50mm cable from the middle post to the negative of the
lithium bus bar. The Alternator cable connects to both a spade connection on the BMS 12/200 and
a three pin plug. The BMS 12/200 requires a constant positive and switched positive
fed from the main lithium Battery Management System. If you suddenly cut the load whilst an alternator
is running, for example if the batteries were full, it can damage the alternator. So to
avoid this I have used one of my previous lead acid batteries as a bit of a power dump
protector. I will need to have a small load on this lead acid battery however, otherwise
it won’t provide that dump load protection, if it’s totally full all the time. Before the BMS 12/200 was installed, at tick-over I would see around 130-160 amps being pushed into the batteries constantly,
until they were totally full. The time my 300Ah of batteries took to charge
from 50% to 100% was 75 minutes. After testing the BMS 12/200 with a 150 amp,
a 175 amp and a 200 amp fuse, I decided to stick with the maximum of 200 amps. This reduced
the load on the alternator and you could hardly feel any difference when it was in load and
it worked fine at tick over. The amps gradually reduced over the duration
of the charge, protecting the batteries and reducing the chance of overheating the alternator. The time my 300 amp hours of batteries took
to charge from 50% to 100% with the BMS 12/200 and a 200 amp fuse was 88 minutes. Although this is slightly slower, I’ve added
the ability to cut the charge automatically as well as reducing the charge current over
the course of the charge. The values set within the lithium BMS, to
me, seemed extreme and you can’t change them. The lithium BMS has a fixed over voltage cut
off of 4.2 volts in any one cell. It has a fixed under voltage cut off of 2.5 volts
in any one cell. However, I already have the kit to tackle this. In my true belt and braces approach, I wanted
to change these voltages. I knew all it would take for the charge or load to be cut, is the
disconnection of their positive feeds. This would cut both the solar MPPT and the alternator
in the event of high voltage and the load if the voltage got too low. The BMV 712 battery monitors are already installed
measuring the amps in and out, the voltages and the percentage left in the battery bank.
Inside the battery monitor is a small relay. So I wired the positive feed from the lithium
BMS, via the relay. It’s recommended the Victron lithium batteries
reach 14.2 volts during their charge so the batteries internal circuitry can balance the
cells. Within the settings area of the BMV 712 there
is a relay tab. I changed the relay to charger mode, inverted
the relay, set the Relay-off delay to 3 minutes and then set the High voltage relay to disconnect
the relay when it’s at 14.3 volts. After a bit of tweaking, the batteries reach
14.3 volts for 3 minutes and then the charge sources are turned off. No high cell voltages
of 4.2 volts! Now to deal with the low voltage.
I already have a second BMV battery monitor

[Thought I’d give you a rest from non stop batteries!] connected to the alternator protect lead acid
battery. The monitor has the ability to monitor

[Thought I’d give you a rest from non stop batteries!] an auxiliary or starter battery. So I’ve wired
this connection to the bus bar of the main lithium bank. Once again in the settings I changed the relay
to charger mode, inverted the relay, set the Relay-off delay to 3 minutes and then set
the starter voltage relay to disconnect the relay when it’s at 2.9 volts. The relay of this second battery monitor disconnects
the load positive feed from the lithium BMS. This doesn’t deal with the MultiPlus Inverter
however so I need to look into a way of automatically disconnecting that too. However the low voltage
will be a very, very rare event as I don’t let my batteries get below 50% to increase
their lifespan, plus there’s always a little bit of charge from my solar panels, even if
it’s a horrible winters day. I am now confident not only are my lithium
batteries treated better whilst charging, but I have introduced a more conservative voltage
protection. I’ve included links to all the items I’ve
discussed in this episode in the description below. If you like this episode, do please give it
a thumbs up. If you’ve not already subscribed, hit that subscribe button and click the bell
icon to be notified about all my future episodes. Until next time, see ya later.

100 thoughts on “Lithium Battery Charging with an Alternator

  1. 8:19 is it my imagination. Or does molly go from happy face too WTF face the second you mention lead batteries 🙂

  2. Hi Jono, I'm in a very similar position to you (Liverpool sailaway, about 1 year liveaboard, lithium batts, Victron inverter/charger and Victron MPPT controller). I have the same alternator package as you and you mention that the alternator is a bit harsh for your lithium batteries. Can you explain what you mean by this and how you came to that conclusion. Cheers, Rick

  3. that is the coolest dog. is there a more simple way to charge lithium? I have a 24v system with 29v li ion. cells. 7 in series. I would like to build a DC generator for sunless weather. thanks. I wish to know more.

  4. Jono, you seem to be going all bells and whistles regarding the lithium installation but I was wondering, purely out of interest, if you can just upgrade to lithium without all the control systems your installing? I get the temperature considerations but can you just site the batteries inside and leave everything as previous with lead acid?

  5. Just watched all you videos regarding your lithium installation, thanks I certainly have learned something it was a great deal more complex than I thought it would be. I guess if you are spending all that money you want it to last. Just interested but do you have an electrical background? if you don’t I am even more impressed. Thanks again

  6. Thank goodness I’m an electronics technician 😉 a great explanation and I even learned something new 👍 Cheers.

  7. my god! are you a journalist or an electrical engineer! how do you know all this stuff? very interesting though. i had a question: you've mentioned picking up your car, how do you do this? do you catch buses from where you moor to where you left your car? please make an episode on that. also please make an episode on stopping and emptying the toilet and trash and filling water and diesel and groceries! thx.loving your channel, will give more suggestions in the future 😉

  8. If the Royal Navy needs an electrician's mate for HM submarines, watch out for the press gangs. Oh yeah, you don't have press gangs anymore.

  9. Super stuff and if anyone is really considering a battery swap like this very worthwhile V some sales chat. AFAIK the lithiums will be pretty stuffed if asked to charge 5C or below (a possibly very expensive experience). Considering a narrow boat and happy to spend enough easy life money but that temp charge issue scares me. Sorry if I missed it but was there an overall price for the entire package? Keep up the good work and thanks for your vids………BTW great lab. Mine are still sorely missed having left this mortal coil. Hopefully see them on the other side:)

  10. Great stuff. Didn't understand a bloody word of it but beautifully presented and nice pictures of the Dog

  11. сильно не разряжай ,а то придется разбирать они 3,2 вольта , 12 вольтовые могут уйти в защиту

  12. hello, great setup. as I see, you have a 12v battery pack with high amp. What motor do you power with it? I am sorry if I missed stg you explained earlier, I just noticed your chanel.

  13. Awesome dog. Good info. Thanks for posting this. I'm considering doing a bit of solar at the house. Maybe a small battery wall type of thing. Fun stuff.

  14. Hi Jono, I’m really impressed with your work, explanations and editorial skills. We run a simular set up although I’ve not connected to an alternator, mainly as it’s a vintage engine and hasn’t got the power, but am looking at doing it now. The thing that has confused me with how you have set up is the charge voltage from the alternator, what is regulating the voltage? Also I’m assuming there would be no need for the buffer battery if I had the starter battery in line?
    Thanks Phil

  15. Hi Jono – Thanks for all the well-researched and informative videos on 12v electrics and LifePO4 batteries. I am considering this option too. In my campervan (with AGMs) I decided against the split charge relay method and instead installed a DC-DC charger (Ctek D250SA) which seems to work well and has an intelligent multi-stage charge profile. These can't be used with LifePO4 but Sterling do make a DC-DC charger (Sterling Power BB1230 Battery to Battery Charger) that has this capability – This may be a good solution to the problems of safely/effectively charging LifePO4 batteries via an alternator. There may be other similar products available. Ctek now make a smart mains charger for LifePO4 that may be usefull for campervan/RV users

  16. Hi Jono, I m following your electrical install at the moment as it seems to be everything I need to complete my build. Great information so thanks so much for all the time youve put into this. I do have a question that I hope you may be able to shed some light on. I will post on 12V fb page as well. For at least the next year I will be berthed in a marina whilst completing my boat, I will have more power requirements than average as I will also be setting up a small recording studio on my boat as well as living aboard, im estimating anywhere from 300-500ah per day so i guess im going to need a large battery bank. My question is how reliable have you found shoreline power to be in your experience. Eventually i will build my system out to be self contained as is yours but whilst i am in the process of building i want to be able to use shoreline power but have a battery backup system in place to 1.regulate any instabilities that may occur with the grid or even total power failures.and therefore 2. Keep any critical systems going such as the computer for a short time so i can backup whilst power is down. Do you think its possible to have the minimal amount of battery power needed just to keep the shoreline power stable and build out battery banks as funds permit? Any thoughts much appriciated. Cheers.

  17. sorry to bother you again johnno, I'm wanting to solar power my shed (long distance from house) once I get the panels ,battery,charger/ inverter would I need a charge controller or is that built into the inverter

  18. Jono, I've been following you for a few months now, and I find your videos to be hugely educational and well executed.
    And your cable management is off the charts… outstanding job… never seen anything so cleanly done.


  19. I am installing 4 x 105ah AGM's on my sailboat with a Yanmar 3hm35f diesel. It currently has 4 lead acid batteries in parallel and NO dedicated starter battery. I am hoping with the AGM's I will still be able to start my engine as I do now. The CCA rating seems to be enough. Any issue with this? Also, I bought 5 x 100 W solar panels and two victron mppt controllers. The plan is to split the solar panels 3 x in parallel with one charge controller and 2 in parallel + a wind charger with the other mppt controller. I do plan to fuse both upstream and downstream from the charge controllers. Any problems you see? Lastly, I bought 721 victron battery monitor, but not sure which NEG to connect it to in the bank of 4 batteries.?..I am thinking the one where my alternator connects is probably the right one…please comment and thanks for a great video.

  20. I recently purchased a 40 foot motorhome that is configured with Victron LiFepo4 batteries (2X300 amps) 1500 watts of solar via a Victron MPPT 150|1009 TR controller and a Victron 3000|120 Multiplus inverter charger and a Lynx distributor. Was the system I wanted to put in my next boat, but got a land yacht instead…. Looking to charge the lithiums from a high output alternator and will look into your system a bit more. Would need to research this a bit more on Victrons site. They show a alternator charging a lilthium setup but not how they control it. Looks like you're on to something. While I can stare at a good Lithium system anyday, your pup is to cute.

  21. Great video and great wiring of your boat electrical system. I am wondering at what voltage you recharge your battery banks. Are these batteries able to be used as deep-cycle or are they basically used as starter batteries?
    I have not yet had the opportunity to see a 12V LiFeP04 battery nor to test or charge one. I live in the heart of the USA and this type of battery technology is not yet mainstream due to excessive purchase prices.
    Do these batteries only have two terminals or are there electrical contacts for the BMS to monitor and manage the middle cells as Lit-Ion battery packs when they are charged?
    I have just received a shipment of new 18650 LiIon batteries and I am planning on performing an outdoor experiment charging four of my older cells in series attached to a 12V auto battery. I will do this in an open shaded area behind my shop using a sixteen-foot-long set of battery jumping cable-set to attach the four cells to the auto battery. If things go well I will then add a standard 12V battery charger to apply a trickle charge to the 12 battery. I will be monitoring the Auto battery voltage and periodically disconnect the negative lead of the battery jumper cables to test the series voltage of the four test 18650 batteries. I will also monitor the temperature of the 18650 batteries for excessive heat. If one or more explode, no harm will be done and I will know that this type of charging cannot be done safely.

  22. I am installing a bank of (Non-Victron) lithium 10 x 12Volt 200AH batteries in parallel to a widebeam liveaboard with 5kW solar array. Like you I want to protect my investment when using the alternator. I was wondering if this BMS 12/200 and VE Bus BMS work with non-Victron lithium batteries or is there a proprietary circuit inside the Victron batteries that must be there?

  23. This isn't meant in a bad way, but you sound like the Jet2 recording that is played when you board there air planes..

    Clear, concise, interesting and makes me feel like I am going abroad on holiday 😂👍👍👍

  24. I'm trying to decide whether to get bms for my 160Ah LiFePo4 bank. I'd need it for measuring SOC and triggering latching high current relays in event of HV/LV. Did I understand correctly that this could be done by BMV 712 itself?

  25. Jono, the belt on the leisure alternator does not have sufficient contact area in my opinion. You may experience slippage at lower RPMs when the torque requirement is high. If it were me, I’d add an idler roller near the alternator such that the belt will wrap around the alternator pulley. You’ll most likely need a longer belt.

  26. since you have 3 100AH batteries wired in parallel,you now have a 300AH battery…..correct? the correct recommended charging current is 150A ..NOT 50A!

  27. can a split charge relay used in lead acid systems be used with lithium without bms or is bms built into the battery? how is it possible to protect a simple 100ah lithium setup.?..i realise i will lose some power through the invertor but im more interested in keeping the batteries in good it safe to add a solar panel for extra power input.? most of all i want my investment to work.

  28. Am wondering what your net system monitoring and control system, power consumption is with all those systems (while I expect small that much has to start adding up). What is your full system continuous capacity with decent solar and cursing?

  29. I love your specificity in regards to "what" equipment you used in relation to the other components of your system. I am researching various systems for my own application. I would love to hear a little more of "why", as it applies to your needs. Integrate the "how", "what", and "why" in your presentation…… it would be excellent. You can do it… just think about it …..systematically!

  30. Jono why have you not used an external alternator regulator with LFP charging parameters? I think they are also manually programmable? Eg balmar range of regulators.

  31. Jono, when you say "I wired the positive feed from the lithium BMS", through the relay, do you mean the BMS12/200 or the VE-Bus BMS?

  32. hi. have you ever considered "smart" external alternator regulators? I found, at least balmar and mastervolt make ones (some one else?). these have multistage charging and have lithium battery profiles. would solve the problem at the source 🙂

  33. Set low side cut off at 2.9 volts? are you monitoring a single cell somehow, and not all 4cells like the high setting of 14.2?

  34. nice donne i would choose at this point a different bms system totaly… love the victron battery monitors…

  35. Hey Jono I'm new to your channel great videos on the Victron systems I'm converting a hwy bus and buying Victron for my off grid
    System when you went to Victron
    For your visit you did the narrator for the VW van install I'm curious when the part 2 on the alternator charging application will be out
    I'm hoping to be able to charge my batteries and run my 120 volts applications going down the road I've got a 24volt alternator and it's capable of putting out 250 amps
    Which is primarily for the coaches systems but really want to use it as well driving down the road.
    Anyway great videos and thanks for sharing.

  36. Nice vid, nice work. Designing solar/lithium power for my 5th wheel. I'm interested in using my second alternator to get as much safe charging while towing as I can. This gave me good points to consider. Of course seeing Molly made me stop hearing you.😋. That's why they invented rewind.

  37. Hi Jono! I've loved your videos and they've inspired me to potentially go the sailaway route. One question though; as informative as your videos certainly are, do you have a website or book you use to get your detailed info from?

  38. I imagine living on a canalboat one would have the means to acquire the high quality and not so cheap victron stuff

  39. At 4:45, you state that in this setup a fully charged "house" lithium battery might damage the alternator that keeps producing all that power without any corresponding draw but doesn't its regulator reduces the output ? That happens all the time with the engine's battery that usually stays full.

  40. Excellent video congratulations, no one can help me, I would need an electrical project with Victron energy component, for camperized van system, I would like to charge the batteries with the engine alternator, both with the PV panels, but also have the current 230Volt if I go camping.

    Can someone help me??? My name is: Osvaldo

  41. In your setup can the engine's lead-acid battery be charged from the lithium house batteries and/or the PV panels? And if the engine's battery is drained are the lithiums setup to start the engine?
    Thanks for the video!

  42. Hey there!

    I've started watching your videos for a while now, very entertaining, thank you! One thing that popped into my mind (I'm an electrical engineer) watching the episodes on you switching to lifepo…why not just buy a tesla power wall 2? These victron components are quite expensive (I mean the batteries alone cost over 3000 pounds), although for sure, good quality (kind of like gardena is for garden stuff).

    You now have 3.6 kWh of storage (3*12Vx100A if you fully cycle the batteries), while the powerwall 2.0 has an impressive 13.5 kWh (!) built in, plus it even has the inverter, and a solar charge controller too at a total cost of around 5400 pounds (which, considering how much that would cost if built from victron stuff, is a really great price). For a new boat (or a total overhaul of a used one) I think it would deserve a consideration! Of course then you'd build out your boat to have 230 V all over, instead of using 12 V, which, in my opinion is a big advantage since then you are compatible with off the shelf domestic appliances. In your case you already had a bunch of 12 V stuff so I understand that's less of a positive (although you can always install a 12 V SMPS, which are highly efficient). Personally I really dislike low voltage high current circuits in a household (or, honestly, anywhere where it's not specifically required), mostly because you need a ton of copper for the same wattage, and every connection has to be that much more secure, since even small contact resistance can cause a lot of heating (due to the high current), and increase the fire risk, losses, etc…

    Okay, correction: The powerwall does not take the DC output from the solar panels directly (it has no solar charge controller in it), so you'd need a solar inverter to feed the powerwall. But since that inverter does not have to take the load of the boat, just the maximum power from the solar panels , in your case a 600 W inverter would be sufficient. Which are a lot cheaper than multi kW models.

  43. Did you ever come up with something different than a dump battery? I came across an alternator protection device from intended for marine use.

  44. If you want the batteries to last longer, keep them charged between 20% and 80%. Balance them as needed or once every 2 month.

  45. Great video with explanation, but fuses don't control the flow of current. They rupture when their rating is exceeded to protect. Does the Victron BMS unit use the fuse as a shunt? You already have a shunt though.

  46. Posting as a professional designer of industrial grade battery management charging systems, I am very impressed with your approach to the battery and electrical systems on your boat. Superb job Sir, well done.

  47. In the opening sentence of the intro to this video you mention your "Lithium iron (?) phosphate" batteries. Is this something new?

  48. Thanks for all the great information, I have a question.
    I'm currently working on a camper van, and iv been looking into getting lithium batteries, but I'm wondering about charging them with my alternator, the set up you have is pretty big, and space is precious in the van, is there an alternative to all the charge controllers and what not that you have just to down size it a bit?
    i was considering a battery isolator but so far iv come short and everyone says they are a bad idea for lithium.

  49. Do you have a Schematic Diagram for your final layout. I am finding it a little tricky to fully understand! Great information though. I must have watched them each 5 times over!

  50. Hey Jono, , are you talking about the positive feed from the Alternator Control cable from the BMS12/200 to VE.Bus Charge port or the positive feed from the Battery to the VE.Bus positive battery port?

  51. I moved over to Lithium on my caravan and had all the electronics installed to protect and to charge it correctly . With 300w of Solar It’s a different world !

  52. Hi Jono, nice work around however you and 90% of the population have DC wrong. Direct current or DC electricity is the continuous movement of electrons from an area of negative (−) charges to an area of positive (+) charges through a conducting material such as a metal wire. Whereas static electricity sparks consist of the sudden movement of electrons from a negative to positive surface, DC electricity is the continuous movement of the electrons through a wire.

  53. You need a way to disconnect the Multiplus for low voltage? I dont get it. Why is programming the low voltage shutdown in the VE config for the Multiplus not sufficient? From what I can see, their are several redundant and unneeded Victron parts in this setup. I must be missing something.

  54. I was looking for a video on how to charge a lithium battery bank with a portable generator…Since most portable generators use an alternator I found your video here very useful. My inverter just assumes charging from the grid and doesn't have a separate option to charge from a generator so I am hoping I can fake the inverter into thinking it is attached to the grid when it is really attached to my generator. I plan on adding a switch so I can switch from charging from the grid and charging from my generator when the grid is down.

  55. Hi
    Jono great videos are very educational. Need some guidance. We are getting a Collingwood Pioneer new build for next year. Really struggling with how to set up electrics for continuous cruising the boat will have 32 tv, wifi, integral freezer, and fridge. LED lighting etc. What would you recommend as in Battery numbers sizes(ah)? Have ordered the Vicrorn 3.5 kw Inverter. Should I have a generator and solar panels?

  56. 150ampX12volt= 1800watt =2hp on your 42hp engine you wont feel the difference. of course its not perfect efficency, but even at 5hp load your diesel engine wont feel it turn on-off if its not at idle.

  57. In a lithium cell, there is very little current below 3.1 volts. and over 3.8 volts. (Meaning 80% of the usable battery current is between those two points. )
    All true lithium chargers have a charge curve giving a fast charge to a certain spot (called the knee) then floating the rest slowly. They also monitor each cell for capacity. The trick is to keep every cell at the same exact charge or the highest cell will shut off the charger early before the rest are truly charged. And conversely, the lowest cell will shut off usage early to prevent cell damage. Combine those two conditions and you only operate with maybe 60-80% of your potential. It is mandatory to keep the cells balanced to get the full benefit of Lithium.

  58. Hi, I'm not sure I followed what you said about the BMS, how will changing the fuse limit the current without blowing the fuse, or do you change the settings to limit the current aswell? I'm setting up an off grid system with 8 x 160AH Victron lead carbon batteries, 48v 3kva Easy solar and Bmv 712, I've got 6 x 300w solar panels to fit, but it's just being charged from a 10kva kubota generator at the moment, so far it's performing very well..

  59. Did you consider a Cyrix-Li-Ct in your setup? This also has the ability to be connected to the Ve.Bus BMS with disconnect switch. I like your approach of being able to configure everything to your needs.
    It sounds counter intuïtive that a 200amp fuse would charge slower, this confuses me. Are you comparing to a 150amp fuse or to your previous (non BMS 12/200) setup?

  60. This is just what I have been looking for. After one quick watch through I know I should save this video in my favorites.

  61. I spent the last several years of my life on solar systems design and install, but today, on this video, I learnt plenty. Thanks.

  62. interesting – not familiar all aspects of this – but i was sort of expecting the controllers to be altering the field voltage on the alternator in order adjust the charge rate. I think modern alternators are controlled digitally(via can bus i assume). Seems like an opportunity to make charging much smarter

Leave a Reply

Your email address will not be published. Required fields are marked *