Can you Charge LiFePO4 from your car? Mailbag Monday #28

[@jakep5121]

Having titles on the mailbag Mondays is handy. Maybe even better, some chapters or the description saying what the questions are.

[@jakep5121]

I see you did that... nice 👍

[@hamradiotube]

I’ve pretty much always put chapters and subjects in the description of all the mailbag monday videos. I’m working on better thumbnails now though.

[@peterdekeles.]

Always love batteries and power pole videos. I need to go find something to powerpole

[@fartsonbasketball9206]

No other videos on this out there. Thanks for the time you put into this.

[@johngriswold]

Stripped wire should not be twisted before inserting into the crimp connector. It weakens the crimp and can add resistance. Great content. Thanks!

[@hamradiotube]

Hmm, I've never heard that. Thanks for the tip.

[@DagonNaxos]

I'd go with the boost converter option purely for efficiency sake. Converting a DC signal to a partially or fully rectified AC output at an average 80% efficiency, only to convert it back to DC is burning a lot of electrons needlessly and also introducing a lot of noise and electrical component failure points into what can be done simply through some DC ICs and a few zener diodes.

[@hamradiotube]

Oh it's stupid inefficient for sure. But it works.

[@DagonNaxos]

@@hamradiotube Oh of course. In a pinch, you gotta do what you gotta do, but given a choice....

[@aldewitt9]

Great video. I used a 6 port power pole distribution block and ran the solar controller to it. Then I connected it to the battery. All that did was create additional points of failure. I like your method.

[@DK5ONV]

Mikey you are a Tech...good job. Tnx for speading this out to the whole HAM Radio World & beyond. 73 de YFUG 💯🙋‍♂

[@bruceforster5993]

Better than Radio Shack's ad blitz from several years back. Welcome to Radio Shack. You've got questions: so do WE!

[@jamescstanley5018]

Hi mike, I am setting up my car for mobile/portable ops. I am using a split charge relay, used to charge caravan batteries on the move. I am using lead acid, but you could charge anything using your system. One advantage is that you do not drain your car battery as the relay senses voltage. Will let you know how it goes Jim M7BXT

[@chrisazure1624]

Yes, I have. But it will depend on how much your alternator puts out.

[@ac0m-glennthompson432]

Dang, you're so smart, you make me feel really old (I am) and stupid. Good job, love your videos.

[@lousadventures2111]

I have a power inverter with a separate 12v battery to a solar charger. solar panel mounted on the luggage rack permanently LOL Like that when i drive from p2p i plug in to the power inverter 110v . 73s de n3lou

[@jasonodette8607]

Thanks Mike 👍

[@aa3konthego]

I've been using a small inverter to recharge my laptop between activation sites or when heading home.

[@stevegriffin9552]

Hey Mike great video on the batteries and charging them. Those power poles are awesome to use. I hope you have a great week and weekend. WD5ENH Steve

[@rogerhansen5474]

Love your videos! It wouldn't be a bad idea to add an inline fuse to your direct battery harness. As a former automotive tech it makes me nervous to see an unfused connection off of the battery. 73 Roger N0LIA

[@pedrocatalan9814]

Good video bud. Only thing I would add is when attaching direct to battery with alligator clips, you probably want inline fuses on both positive and negative terminals. Last thing you want to do is have a short direct to the battery. That’s from first hand experience. *pouf*

[@hamradiotube]

So we don’t want the magic smoke?? Good idea.

[@notreallydaedalus]

I like to put a high-power, 1 Ohm resistor inline. The delta-V isn't generally big enough to need much current-limiting, but for small capacity batteries, a 1-ohm chokepoint eases my mind. And I haven't damaged a battery, or melted a wire yet!

[@the_mad_swimbaiter455]

Nice video Mike. Keep it up! I need to build that car power sup!

[@hamradiotube]

Everyone should have power poles in their car.

[@javierpolendok5mhc]

Great ideas

[@douglasvamateurradioandmore]

On my 21 f150, It has shown 14.2-14.6 v charging, which is strange, but it doesn't always show that. I still use an inverter or maybe the paradan, just to be safe. My truck came with an agm battery from the factory.

[@DagonNaxos]

When a car is running, most alternators put out 14.6-15V and the battery, when topped off, will show that as a surface voltage, but as soon as you draw any appreciable current from a lead acid battery, be if FLA or AGM or GEL, it will drop the voltage to 12.8-12.6V, well below the min charge specs of a LFE or NMC battery. Plus, LFE batteries need different charging stages to properly charge. There's bulk charging, absorption, equalization charge, float charging etc. Most bigger LFE batteries do this via a built in Battery Management System (BMS) but most small LFE's don't have a built in BMS, thus the need for an external multi stage charger, boost converter etc. You'll cook an LFE battery otherwise.

[@SmokeSignalsRF]

Life is easier when you PowerPole the everything……Great job….PS : Don’t forget to check for French fries 🍟 and coins between the 💺 seats.

[@hamradiotube]

I ate em all before filming lol!

[@kevinwelsh7490]

I have a dumb question: will this work if I run the inverter from the cigarette lighter receptacle and will it supply enough juice for a 6 amp charger? What is the wattage of your inverter, and what wattage should I use connecting to the cigarette lighter receptacle?

[@robertmeyer4744]

should be ok. check current threw lighter port. keep it under 10 amps.

[@Thunderontheroad]

Most cigarette lighters are rated for 15A or 180 watts. Volts X Amps gives you wattage. 6amp draw should be 72 watts there will be some loss so really 80-85 watts.

[@chrissewell1608]

Easy, Peasy!

[@ndubpcplug6149]

Im wondering why not just bypass the charger all together and connect the battery + /- directly to the car +/-. I do this with my 100ah Bluetooth battery where I'm able to watch the amps when I first hook it up I have all my accessories on (air, headlights, dome light) becuz at first it usually it's over 60amps then after less than a min it drops to below 50amps then I turn off accessories and charge for about 2-3 hrs for full charge. Is this ok for the battery? Btw my battery is fairly new and the voltage drops below 10volts before the ah reach 50ah and need to recharge. Plz help did I screw up my battery

[@WX4CB]

you would really want a battery isolator between the two because when you try and start the car, the car will pull from whichever battery can supply the current.. ALSO, if one battery dies (eg the sla in the car) then it WILL drag the other battery down with it.. not to mention the differing chemistries and related voltages involved

[@W9HJBill]

I so can't wait for the BuddiPole PowerMini 2 to come back in stock. I want to pick up another. Having said that, I wonder if you could just plug your battery into the battery port of the PowerMini 2, plug your car battery into the solar port of the PowerMini2, and charge your LiFePO4 battery that way, AND have 2 power poll outputs. Thoughts? Also, what make and model DC to AC inverter are you using? I was hoping you'd mention it since I assume yours has a nice, clean, AC output. Great video!

[@W9HJBill]

After doing some digging, I'm guessing it's the CEN-TECH POWER INVERTER 66814 400 WATT CONTINUOUS 800 WATT PEAK. Did I guess right?

[@hamradiotube]

I’m honestly too lazy to get off the couch after dinner to check, but it’s from harbor freight and I would not recommend it near radios if you are operating. It puts out an incredible amount of RFI.

[@DagonNaxos]

No. A solar charge controller, be it a PWM or MPPT, needs a minimum voltage of 17VDC + to activate and start the charging process. Now, if you put a 12VDC to 24VDC boost converter and then hooked the solar charge controller to that, then yes. But why would you.

[@Schlimm1969]

There's an XT60(?) connector on the back of my HiTec charger - is not that a DC input, and could it be used to connect to vehicle DC, rather than going thru the inverter (DC > AC > DC)?

[@hamradiotube]

I’ve not done it but I believe you very well could do that too. Good idea.

[@petemillis4666]

Yes it can. I have xt60 on my charger and it can take input 8 to 16V. 73 de M3KXZ

[@MrJuanderful]

How long Aprox would it take to charge a 100ah lifepo4 from a charger running off the inverter powered by the car battery ?

[@waltbury]

Hey Mike or should I say- Ex Michigander. Most cheap inverters aka Harbor Freight are only 1/2 sine way inverters. So my question is does it make a differance if you a 1/2 sine wave or full sine way inverter. My wife and I were fulltime RV's for several year. All the electrical Rv experts tell you to use full sine way inverter when charging/ using your electronic gear. does this apply to battery? Walt N8WEH

[@pen25]

depends on the electronics. half sinewave can kill a battery in a laptop least they used to. havent seen that happen in the past 10 years. always best to buy a good pure sinewave inverter though in reality none are pure and are more square wave then sine.

[@DagonNaxos]

It absolutely does! You want to use a full sine inverter instead of a mod sine inverter because you can burn a charger brick up with dirty power and, even worse, you can blow your electronics up. A mod sine inverter is only really supposed to be use with inductive loads, like power tools and other motor driven appliances, because they have rectifiers built in (in most cases). Mod sine inverters are considered "dirty" power. So I'd ALWAYS recommend spending a little extra coin for a full sine inverter for anything electronic. Plus, in the ham radio context, mod sine inverters are noisy as heck and will introduce a lot of RFI and hash into your signal. Another tip: always try to ground you inverter whenever possible for both electrical safety and also to cut down on the noise. I don't mean DC ground, either. I mean earth ground. This may or may not be possible and most good inverters will simulate a "float" ground, but I wouldn't necessarily rely on it solely for safety.

[@DonzLockz]

I need to get some of these dinky "power poles".... down here, cars always crash into power poles! 😄🇭🇲

[@solidloud1922]

i was wanting to make a battery box and put a solar charge controller into it. can i also have the 12v car output go into the solar charger for when charging while in the car, my thinking is the solar controller should regulate the battery as if its a 12v solar input?? iam going to put a second dc port in for charging when at home using a power brick like yours in this video.

[@hamradiotube]

A solar charge controller is looking for a higher voltage. In the neighborhood of ~18-22 volts. It most likely won’t even turn on with the 12v from your car. You can always plug it in and find out. It’s not going to hurt anything.

[@schwuzi]

​@@hamradiotube It depends on the charge controller. A cheap PWM charge controller will short the input to regulate the voltage. That is not a problem for a solar panel, but it is a problem if you connect a power supply, e.g your car to the input.

[@frankwc0o]

What's the name of that charge controller? Looks very slim.

[@barrybogart5436]

Don't you need a proper MPPT controller like the Buddi one for an LiFePO4?

[@hamradiotube]

No

[@notreallydaedalus]

Not MMPT, that's only for extracting the max juice out of solar panels. You need a CC-CV power supply, which is the brains inside a Lithium ion charger.

[@tanksleyn]

My little inverter makes so much noise on hf its not usable

[@bruceforster5993]

A good PURE sine wave inverter might solve that issue.

[@DellFargus]

Your alternator must hate you. In a pinch, I would think that you would be able to just put the LiFePO in parallel with the car battery. I wouldn't do it often, because it could pop the LiFePO or its BMS, but 12 volts is 12 volts.

[@DagonNaxos]

Negative. LFE charges very differently from SLA or FLA batteries. You'll warp the cells and do permeant damage to them if you try this. SLA batteries bulk charge to the last 10% and then float charge beyond that. LFE batteries need different charging stages to properly charge. There's bulk charging, absorption, equalization charge, float charging. That's why LFE batteries have/need BMS systems. The BMS also does what's called bottom and top balancing of the individual cells in an LFE battery, because if you over/under charge one of the cells, you do damage.

[@notreallydaedalus]

12V is 12V, but 13.8V isn't 11V. If you hook a depleted LiFePo4 cell up to a charging allternator, as Johan indicated, the huge available current can destory you LiFePo4. If they're close in voltage, you have no problem whatsoever. If you have a top-notch BMS, you won't do any permanent damage. But without comparing voltages, measuring cable resistance, and invoking the power of Ohm, I'd much rather use a constant-current power supply.

[@fratermus5502]

@@DagonNaxos > You'll warp the cells and do permeant damage to them if you try this Some of us have actually tried it, and are direct-charging well within the battery's and alternator's specs. I=V/R like everywhere else. > LFE batteries need different charging stages to properly charge They do not. Charge-and-stop is generally considered optimal. > The BMS also does what's called bottom and top balancing of the individual cells in an LFE battery Most commercial LFP batts do passive top-balancing only.

[@DagonNaxos]

@@fratermus5502 Maybe I wasn't detailed enough. First, yes you can charge the battery off a battery and alternator, but a battery any battery, will absorb as much energy as fast as you let it, so without some sort of volatge and amperage regulation, depending on the battery's specs for max charge rate (C rate), you can and will absolutely do damage to the cells. Plus, no matter the chemestry, exceeding the maximum C rate for either charge or discharge will generate excessive heat inside the cells, causing cell drgradation and significantly shorten the life of the battery at best and an over pressure and possible safety valve blow off at worst. You don't want to breathe in gassified lithium. Bad news. 2. Yes, it's true that LFE batteries do "bulk charge" between 10% and about 85% state of charge but, again, modulating that volage and amperage is very inportant for the resons stated above. If you want to charge beyond 85% and "finish" charge the battery, there are certain things that need to happen that the charger or BMS has to handle in order to do that. Ever notice how an LFE or NCM battery can charge up to 80% in like a half hour, but the last 20% takes 1.5h? That's because it slows the current down and modulates the voltage and it constantly reading/balancing the cells via the BMS to optimize the battery. 3. Most small consumer batteries only top balance, yes, but for optimal battery performance and life, the bigger more expensive batteries do both. But the fact remains the there is always SOME circuitry that is checking the SOC on the individual cells and making them as even as possible Last, I NEVER said it wouldn't work or that you couldn't do the things I mentioned, but you have to remember that not everyone delves into these things as far as you and I have here in this conversation, nor should they have to. My recommendations are based on safety, experience, research and general best practices to get the longest life and best experience out of the batteries. Ibalways err on the side of caution and safety when dispensing advice to the general public, because I don't want them doing something that, although technically possible, could cause injury or catastrophic failure.

[@gmanshackshack6822]

Epic PwrGate anyone?

[@mannypersonal]

Do say more! I like where you are going with this. I have a bioenno MegaBox w/ a 30ah battery in it. I plan to mount an Epic PwrGate (which charges the battery I hear). The question I have is : Can I simply connect a 12volt (cigarrette lighter adapter) to anderson PowerPole connector, plug it into the car and call it a day? The hope is that while I drive the car, it slowly tops off the battery. However, I run my mobile radio by connecting directly to the PWRGate. Would appreciate any ideas on this avenue!

[@gmanshackshack6822]

@@mannypersonal - the Epic PwrGate is FANTASTIC. It juggles various power inputs car or AC power supply, solar and your battery. It will charge your battery and supply juice to your rig at the same time. It switches between power sources so quickly that your rig won't skip a beat. It's like a UPS for your rig.

[@mannypersonal]

@@gmanshackshack6822 So I did a bit more researching - With a MegaBox and a bioenno battery, you could use the Epic PwrGate as your central hub to input solar panels and proper Power Supply sources. However, if you want to use an a car while operating your rig, best thing to do is to use a charger (Such as the PowerWerx DCDC-8) and plug it into the alternate cable on the Bioenno battery (I added a direct port on the MegaBox' using PowerPoles). Separately, your rig can be connected to the Output of the Epic PwrGate. Done! A topped off battery off your alternator as you drive around, while being able to operate your rig as well. (If you decide to POTA, just grab your rig, MegaBox, and Solar panel, and BOOM, operate at celebrate! :-) )

[@paulct]

I have the Paradan charger. Awesome. I never even take the battery out of the car on long POTA trips. w1ip

[@62chevrolet]

Even for us that know this stuff, your how to’s are awesome. Sometimes you can get some great ideas seeing how someone else does it 73 de KK7BCS

[@hamradiotube]

Well thank you so much!