Charging Lithium Batteries With Alternator

Charging Lithium Batteries With Alternator - Howto Guide

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Күн бұрын

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In this video, I'm going to walk you through the process of charging your lithium iron phosphate (LiFePO4) batteries directly from your vehicle's alternator. This idea was sparked by a friend's van conversion project, aiming to efficiently power his house battery via the alternator. We'll dive into the essentials of using a DC to DC charger for this purpose, highlighting the critical differences between isolated and non-isolated chargers, and why it's pivotal for safely charging lithium batteries with your car alternator.
Understanding why a DC to DC charger is crucial forms the backbone of our discussion. Alternators are traditionally designed for lead-acid batteries, which have a vastly different charging profile compared to lithium batteries. The lower internal resistance of lithium batteries means they can draw higher current, potentially leading to issues if charged directly by the alternator. I'll explain how a DC to DC charger acts as a mediator, allowing your alternator to safely charge a lithium battery by regulating the current flow from your starter battery.
We'll explore several reputable brands like Renogy, Victron, and Litime, offering top-notch DC to DC chargers perfect for charging lithium batteries while driving. I'll share my experience with different models, including a cautionary tale about selecting the right type of charger-emphasizing the importance of choosing a charger specifically designed for your setup.
The video includes a detailed wiring diagram for connecting your DC to DC charger, using a Renogy model as an example. Tips on minimizing voltage drop, selecting the proper fuse sizes, and the advantages of wiring your charger through a switch for greater control and efficiency will also be covered. This setup is particularly useful for those who might alternate between alternator charging and shore power, aiming to conserve fuel and reduce wear on your vehicle's alternator and belts.
Additionally, I'll tackle the often-asked question about the differences between isolated and non-isolated DC to DC chargers. The choice between them can impact efficiency, cost, and the safety of sensitive electronics in your system.
To debunk myths and clarify misconceptions, I'll discuss a Victron test that highlights potential issues with charging lithium batteries directly from an alternator without proper current regulation. Plus, I'll share insights on how to properly size your DC to DC charger in relation to your alternator's output to ensure longevity and reliability of your charging system.
If you're curious about how long it takes to charge your battery with an alternator and a DC to DC charger, I've got you covered. We'll break down the math to give you a clear understanding of charging times, ensuring you can plan your travels without worry.
This video is packed with information for anyone looking to charge their lithium battery from a starter battery, especially for those on the move. Whether you're driving to your next adventure or powering your off-grid setup, understanding how to efficiently charge your lithium batteries with your vehicle's alternator is key.
Your feedback and questions are invaluable, so please share your thoughts in the comments below. Have you used a DC to DC charger in your setup? Share your experiences and let's help each other out.

Пікірлер: 64

@tomede472 3 ай бұрын

Thanks always very interesting and professional explanation about electronics.

@canyondan 3 ай бұрын

Excellent information

@gregsnape9622 Ай бұрын

Really good information, thank you.

@zenzen9131 2 ай бұрын

Perfectly explained :)

@brucew4726 2 ай бұрын

I'm charging my 105amp Lithium phosphate battery with a Sterling BB1260 on the 30amp reduced power setting. My Peugeot Boxer van will charge the battery at around 25 amps until the battery reaches around 75% charged and then the charge voltage drops to about 10 amps and then 8 amps. I'm using 110 amp cable from the starter battery.

@sranjaniis 12 күн бұрын

Good info . Short and to the point videos . No complains .

@cleversolarpower 12 күн бұрын

Glad you liked it!

@VanVentures-oo7bm Ай бұрын

I'm doing research for my ambulance tiny home build and im pretty sure you solved a major problem of mine with this video. Here is my plan. My abulance has 2 alternators i beleave 120 amps each that normally charge 4 agm batteries as a 12volt system. 2 for starting and 2 for box accessories. I want to replace the 2 agm batteries for roughly 300AH 24v. I want a 24v for Air conditioning efficiency and limit amperage of the system in general. My problem was the alternator possibly overheating because of that shotty victron alternator video. I agree with your assessment about it. So i think the 12-24v sterling power dc to dc is perfect for what im doing! Thanks so much.

@cleversolarpower Ай бұрын

I've heard the sterling power dc to dc charger is great (but expensive).

@dan32one44 3 ай бұрын

Good stuff 👍

@cleversolarpower 3 ай бұрын

Thanks Dan!

@markoshun 2 ай бұрын

Excellent videos. Some of the best on any subject, especially considering how complicated this is. Clear, concise. Thank you.

@cleversolarpower 2 ай бұрын

Glad it was helpful!

@garyjunker83 7 күн бұрын

Very professional and good information. Thoughts on a Precision Circuits LI battery isolation manager vs B2B??

@michaelburke1023 2 ай бұрын

Redarc brand is another certainly worth mentioning

@LintiNuci 2 ай бұрын

Salu Mulțumesc pentru explicație. Poti pune mai multe sutitrari sa inteleg mai bine! mulțumesc

@seancarwin8034 2 ай бұрын

Hey good day I would like for you to do a video and how to wire a shunt to a 12 volt battery

@Tom-Travels 3 ай бұрын

Mein Gott! Das ist wonderbar!

@cleversolarpower 3 ай бұрын

Glad you liked the video Tom!

@kais7137 20 күн бұрын

Very interesting video, thank you! It makes me wonder if there is a solution for my problem; I'd appreciate any ideas. I have 2 Honda outboards, each with a 12A charging coil. I also have a 40Ah and a 100Ah LiFePo battery. Is there a way to use the batteries for starting the engines and to charge the batteries from the engines? I guess with the DC to DC charger, I could safely charge the batteries without damaging the coils (what would be the right charger here? 12A? does that exist at all?). But then, the current cannot go back to the engines when I want to start them, right? Or is there a solution? Many thanks in advance!

@stanleybest8833 Ай бұрын

Zeftronics regulators control voltage and amperage. Charge any battery of the correct voltage.

@bobk3745 Ай бұрын

I'm charging a 100 AH lifepo4 battery from either solar or the onboard (RV) converter. My battery charge line (pin #7 on the 7 pin connector) from my dual alternator GMC diesel truck is protected by a 30 amp fuse. Can you tell me how the alternators could be damaged by an over amp condition when the charged line is fused? Shouldn't that fuse blow before alternator damage? Thanks

@TheBioniXman 2 ай бұрын

Not sure that I understand this as on many motorcycles there aftermarket Lithium batteries available to replace the standard battery using the same charging system. I ran one of these on my Ducati for 2 years with no problem. BMW and Ducati both offer a Lithium battery option with the standard motorcycle alternator charging system.

@cleversolarpower 2 ай бұрын

That's weird. Maybe they have a smart alternator that limits the charge current?

@andrewwhite986 2 ай бұрын

They have current draw resistors on the circuit board inside. Design to stop over charging and limit the current. Though these are usually very undersized.

@zaneenaz4962 2 ай бұрын

Charging with lower Currents extends your battery life. Under 0.2C has been often recommended. C =rated current of battery. Typical 100A alternators can deliver most of their power to the low internal resistance lithium batteries

@halfaistos Ай бұрын

Very informative video! In my opinion, one of the best on KZfaq on this subject.. definitively because of the drawing illustration! I just currently debate on BBC Forum "how to protect the alternator", actually, by presenting the video you mention; "How not to blow up your alternator when charging Lithium". You've mention on the video that they make the experiment to fail and you present facts to prove it. However this scenario on their video... precisely exist on my boat; Mercury 150hp has only 60Amp alternator in tight space, hot under the cowling and is forced to charge dual purpose 120Amp 1100 CCA battery. I'm going to use Victron DC/DC isolated charger 18Amp (the only info given to me by some reputable Utuber) Would you installed in this situation higher amperage charger like 30,40amp? What size of circuit breaker or fuse would you use? Could you - by using your magic pen -draw lines from alternator-fuse- dc/dc charger-battery please? Thank you!

@cleversolarpower Ай бұрын

Thanks! In that case you should use a DC to DC charger. It depends on how quickly you want to charge your secondary battery. If it doesn't need to be charged quickly, then no need for a higher current. Please take a look at my video about selecting fuses and wires. For a 18A version, multiply by 1.25 to become a minimum fuse size of 22.5A. This doesn't exist, so choose one up, which is 30A midi fuse. Then select a wire that can handle at least 30A. This is an 8gauge welding cable.

@GaryRust-xj7yt 19 күн бұрын

I have 20A Renogy DC to DC charger. The installation is as per Renogy to my 12 volt 100A lithium battery. The system starts to operate and within 3-5 the cooling fan starts and within another 3 minutes the fuse trips. Any idea where I have a problem?

@eroenker 3 ай бұрын

I've seen a few videos of overlanders using an Orion 12/24 DC-DC converter to fast charge their power banks via MPPT input. Seems like a pretty good solution for 48v systems. Is that a good option?

@cleversolarpower 3 ай бұрын

The input of the charge controller needs to be above the battery voltage. With a regular dc to dc converter, you risk draining the starter battery.

@robinhooper7702 2 ай бұрын

Hi, I love the way you teach. I'm learning a lot from this just one vid, thus far. Thank You. My application is to charge my Lithium Ion batteries(6), wired in series, 12V at 10amps(?) each, which is how my E-bike was assembled, by the supplier. I have retrofitted an alternator that its' rated output is at 12V-145amps. The original setup had my E-bike last only 1-1/2 summer seasons. Very poor for a 3K purchase. At 8:10 you mentioned that I would need a Lead Acid battery to do what I'm planning, Yes? As well as a DC to DC converter. I have, as a gift got a LiFePo4 battery(1). Can I use this Battery instead of a Lead acid one? Since my existing Lithium battery bank is toast, I would much rather use LiFePo4s. Will I still need a Lead acid battery connected straight from the alternator? As far as an isolated and non-isolated converter is concerned. How would I be able to tell if I have sensitive electronics in my e-bike? Since I will be replacing my Lithiums' Do You have a recommendation for a LiFePo4 supplier? Thanks again for sharing your knowledge in these vids.

@cleversolarpower 2 ай бұрын

I'm afraid I don't understand your question. Have you fitted an alternator on an e-bike? If you have a small lifepo4 battery (100Ah or less), you might get away with connecting it to the alternator directly, since you have a 145A one. Add some voltage drop in the wires and test the current coming out of the alternator. Max should be 75A.

@robinhooper7702 2 ай бұрын

@@cleversolarpower Hi, thanks for your reply. And, yes I fitted an alternator to my e-bike. I'm a cabinet maker so I'm not that versed with electronics. How would I add a voltage drop?

@TheoSmith249 2 ай бұрын

@@robinhooper7702Install a resistor use ohms law to to determine value. Resistance is = to Voltage divided by current R=E/I

@robinhooper7702 2 ай бұрын

@@TheoSmith249 Just so that you and I are on the same page. I have a source of 12-13.5 Volts at 145 amps. And I need 5 amps at 72 Volts to operate my ebike. So I would need a Buck Boost Converter to do that. Yes?

@TheCornucopiaProject-bd5jk 15 күн бұрын

You don’t need a switch for the renogy dcdc50. It senses the higher charging voltage on the starter battery to turn on and off. And with solar connected, alertât or charging is limited to 50% or 25 amps, solar would bring in up to an additional 25 amps.

@cleversolarpower 14 күн бұрын

A switch is recommended if you are approaching a campground. Turning on the DC to DC charger while driving will consume more fuel. So turning it off is better at that moment.

@42kwhaum2 2 ай бұрын

i have 90Amp alternator (Sailing boat) and 280AH Lifepo4. I charge directly from the internal regulator. No problem. I use 20mm2 wire, it 's hot but it's limit DC current in this configuration. I dont use BMS for protect diodes in regulator (running with battery swich off)

@cleversolarpower 2 ай бұрын

Did you measure the current going through it?

@tomywrobel6428 Ай бұрын

What would u recomment i am building i am building 500ah battery lithium ion need to put in to semi truck for apu unit to run longer what will be best way to do that

@user-ot5ck3oh8b Ай бұрын

Lithium ion is completely different than (LiFePO4) batteries and don't use one instead of the other.

@GaryRust-xj7yt 19 күн бұрын

I have a Renogy 20A DC to DC battery charger that has been installed as per Renogy's info. When the charger is in operation for about 2-3 minutes the cooling fan starts and within another 3 minutes of operation the fuse trips. The green led is on during this period. Can you suggest where my problem might be.

@cleversolarpower Күн бұрын

Fuse size: 20A*1.25=25A minimum. Which fuse do you have installed? Send me an email because i don't get notified of replies here.

@rickss69 14 күн бұрын

The problem is not the charging...it's the BMS. If it shuts down for any reason there will be a spike which will kill most electronics. If you had a lead/acid battery hooked to the lithium battery you would be safe, but who wants to run dual batteries just to have a lithium.

@cleversolarpower 13 күн бұрын

Never had a voltage spike from a BMS that turns off.

@claeslind9532 Ай бұрын

I just bought the ecoflow alternator charger, still haven’t arrived though

@cleversolarpower Ай бұрын

Seems to be a new product. I will await some reviews from people online.

@creativegoot Ай бұрын

Why to use DC-DC charger at 50% of the rated current of the alternator ?

@librulcunspirisy Ай бұрын

So you don't blow up your alternator

@marcbloch1963 18 күн бұрын

The company „Battleborn“ is advertising on their website a battery isolation manager (BIM - made by Precision Circuits) specifically for lithium batteries which monitors voltage and connects batteries when needed. Under normal charging conditions, the BIM will connect for 15 minutes every 35 minutes. That means that the BIM will connect for 15 minutes, disconnect for 20 minutes, and repeat this cycle until the coach battery is charged. I was wondering if I could install this device in my van instead of a DC to DC charger. Your thoughts please.

@grvsays 16 күн бұрын

How to diy DC dc charger

@cleversolarpower 15 күн бұрын

I don't have experience with that.

@stuartstuart866 3 ай бұрын

I purchased a bluetooth monitored 100Ah LiFePO battery . It would be a great addition if battery manufacturers allowed owners to set their own charge rate from an app. This way no other expenses like heavier wires or DC to DC devices would be required at slow charge rates. Hmm, maybe even an interior charge converter so you could charge directly from solar panels as well. There is so much empty space in battery cases, maybe this could be done?

@cleversolarpower 3 ай бұрын

I never heard of regulating the current input of a battery with the BMS. What brand does this?

@fratermus5502 2 ай бұрын

@@cleversolarpowerSome high-end batts will talk to an external regulator over CANBUS to control alternator output. I don't know of any retail BMS that limit charging current to a given level.

@philbrooke-little7082 3 ай бұрын

These are not needed, all you do is effectively add the lead acid resistance to the lithium charge path and the simplest way to do this is to simply extend the charging lead. Because the charge curve of the lithium is so flat the current and voltage drop remain almost constant. 100s of boaters have done this and saved a lot of money. DC-DC chargers are expensive, inefficient and often limit the current more than needed. You are actually using the voltage drop of the cables to your advantage. You only increase the length, you always keep the CSA large enough to carry the maximum rated current of the alternator. It is also perfectly possible to fry an alternator with a DC-DC converter. I use the long wire method on my boat and have been for some years and it works fine. My truck sadly has a 24v engine system and 12v domestic and so this uses and Orion horribleness. 70A 24v alternator, 30A Orion meaning it takes only around 20A (wasting 120W) from the alternator which is capable of a lot more. Needless to say the ‘lithium profile’ default of the thing was designed to damage the batteries through overcharging over time with a 2hr absorb at 14.2v going completely against cell manufacturer’s recommendations but it will of course mean they sell more batteries by reducing their lifespan.

@cleversolarpower 3 ай бұрын

Did you watch until the end? I talked about this, but it's risky if you don't know what you are doing. If you do not look at the voltage of the starter battery and leave it on while the alternator is not running, you can drain the starter battery. You can set the charging parameters of the orion to a lower voltage, so your battery doesn't get 'overcharged'. Its possible, but i do not advice it ;)

@philbrooke-little7082 3 ай бұрын

@@cleversolarpower I did watch to the end. You use a conventional dumb split charging relay from the starter battery operated by the D+ (warning light) terminal. I have suitably modified the Orion settings to avoid it overcharging the Renogy dumb battery. I will be fitting a JBD BMS, which I have lying around, to the Renogy batteries to give them management capabilities, rather than last ditch protection, and just leave the one in the battery to deal with balancing and cell over / under voltage. The JBD can then act as an overall charge protection from the various charge sources, some of which can’t be modified.

@cleversolarpower 27 күн бұрын

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@hufman9807 4 күн бұрын

Should be called, "charging lithium battery with lead acid"...

@mikez9929 Ай бұрын

😂 'promo sm'

@reveal-lk6ip 2 ай бұрын

The author! Have you eaten too many mushrooms? During engine start, the starter consumes more than 250-300 amperes!! Your DC-DC converter connected in parallel to the battery will die in seconds!

@cleversolarpower 2 ай бұрын

I don't think you know circuitry. When the engine starts doesn't mean it gets sent to your DC to DC controller. If you put on a kettle, your lights are not going to shine brighter.