By Mike Sokol
Dear Readers,
I’m going to do something a little bit different in this column. I’m going to introduce one of my colleagues to you, specifically Dennis Wieske from Progressive Dynamics, Inc. For the last year Dennis and I have been discussing how battery chargers and converters in general work with Lithium batteries.
Since Lithium battery conversions are a hot topic nowadays, Dennis has offered to do a YouTube Livestream with me in a few weeks. The day and time of that open meeting will be announced in next Saturday’s column, but for now I want you to meet him through a basic article he just wrote about the potential problems of upgrading to a Lithium battery in your RV if your charging system wasn’t designed to handle it. Please take the survey at the end of this article so we can judge your level of interest in a YouTube Livestream on this topic.
Page Contents
Take it away, Dennis Wieske…
It’s the newest trend, replacing that old, messy Lead Acid battery in your RV with a new Lithium battery. Just swap it out with your old battery and away you go. No more checking the water level, no more cleaning corrosion from the battery posts. It will charge faster, provide more usable power and last longer than that old wet cell. Most of this is true, but it’s not that simple. This article is about the Lithium Iron Phosphate (LiFePO4) battery and what you may need to know to make an informed decision to upgrade your RV to lithium power.
Are they new technology?
Lithium batteries have been on the market for some 30 years. We have all heard the horror stories of phones, laptops and other Lithium-powered devices catching on fire and creating very dangerous situations. However, the LiFePO4 or LFP battery by composition is not subject to thermal runaway as are other Lithium types. It does not release hydrogen gas as a Lead Acid (LA) will. The LFP battery is by far a much safer power source.
Can I build my own?
Unless you are very knowledgeable with Lithium technology, I do not recommend building a battery from miscellaneous parts available on line. Instead, purchase a complete battery package – preferably UL approved. These units contain a smart Battery Management System (BMS). The BMS is the brain of the battery controlling the many aspects of charging and discharging of the cells in a battery pack. The unique characteristics of the LFP cell make an ideal replacement for the standard 12-volt automobile battery.
Positives +++++++
- On the plus side, LFP batteries are lighter, can be discharged 100% and will charge much faster than the Lead Acid battery.
- They also have a relatively constant output voltage over most of the discharge cycle.
- Many LFP batteries are rated for 3,000 to 5,000 recharge cycles versus 200 to 500 recharge cycles of a LA battery – so up to 10 times the life of a Lead Acid battery.
- You do not need to connect to a trickle charger while in storage like any Lead Acid or Absorbent Glass Mat (AGM) battery requires. In fact, many manufacturers recommend discharging your battery to 50% while in storage.
- You can also see a significant cost savings over the life of the battery.
- With the help of recycling, we may also benefit our environment compared to Lead Acid batteries.
Negatives ——-
- On the negative side; These batteries are expensive. But while your initial cost is very high, over the life of the battery the cost is actually much lower.
- Most LFP batteries will only provide a discharge rate of two times the rated power of the battery. This may affect the ability to start your on-board generator or power a large inverter to run your air conditioner. In some cases, a super-capacitor is added to provide extra peak current for these situations.
Charging at temperatures below 32 F will damage the cells. Some manufacturers are beginning to incorporate methods to protect the cells during lower charging temperatures. The battery will shut off when it reaches 0% of charge. You won’t get a warning unless to have a smart battery monitor.- LFP batteries require a higher charging voltage (14.0 to 14.6 volts DC) than a standard LA battery charger. So using a charger for an AGM or Lead Acid battery may not allow your Lithium battery to be fully charged.
- Plus, you may need to upgrade other aspects of your RV’s 12-volt charging system. For example, your charger must be capable of providing a continuous output at the recommended voltage for an extended period of time. That means that the wire between the charger and the battery must be of sufficient gauge to handle the extra current and have minimal losses at full power. I would recommend no more than a 2% voltage loss end to end. This includes the charger and battery negative connections to chassis ground.
- You’ll also want to replace the Shortstop circuit breaker with a manual resettable circuit breaker (Bussmann CB 185 series or equivalent) with a rating of 120% of the charger or load current, whichever is higher. Note the Shortstop breaker in your RV is usually rated lower than the original charger. It won’t take long before it burns out.
- Any portable generator must be capable of handling the full rated power of the charger plus any additional 120 VAC appliances that will be running simultaneously. The maximum recommended load should be no more than 80% of the generator rating.
- It would help to have a battery monitor calibrated for Lithium battery voltages; this will allow you to monitor your state of charge (SOC) to determine if a generator run is warranted.
- Some converter/charging manufacturers may have a Lithium charging option available for charging at 14.6 volts, but it may mean replacing your original unit.
- Progressive Dynamics offers many Lithium options in the current product line. Each of the “ALL IN ONE” power centers offers an option to change from the default Lead Acid setting to Lithium. Each has a converter replacement section for Lithium charging, as well – a requirement for older models.
- There is also a line of deck mount Lithium chargers. Many older units have an option for manual control of the multi-stage “Charge Wizard.” Manual selection of the BOOST mode will provide 4 hours of rapid charging at 14.4 VDC. Progressive Dynamics is committed to providing quality Lithium converter/charging systems.
Final thoughts…
I hope this provides a clear understanding of the requirements and considerations when upgrading to a LiFePO4 battery. You will have many years of satisfying use when you take the time to do the homework first. Don’t forget there are also Solar Lithium options and DC to DC Lithium converters to charge from your engine alternator.
Disclaimer:
Dennis is a Senior Service Technician working in the Service Department at Progressive Dynamics, Inc. His responsibilities include failure analysis of returned products, product evaluation in conjunction with customer usage, customer support via telephone, and email providing troubleshooting help and replacement/upgrade recommendations.
Hey, it’s me again…
Let’s all thank Dennis for his contribution to our knowledge base. And watch for the announcement of our YouTube Live meeting in a few weeks. Yes, you’ll be able to text Dennis and me questions about Lithium battery charging, and we’ll do our best to answer as many as we can in real time.
Please take the following survey about attending our YouTube Livestream event in a few weeks. We’ll post the day and time of the Livestream next week.
Let’s play safe out there….
Mike Sokol is an electrical and professional sound expert with 50+ years in the industry. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.
For information on how to support RVelectricity and No~Shock~Zone articles, seminars and videos, please click the I Like Mike Campaign.
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According to an interview with Denis Phares, the CEO of Battle Born batteries, BB batteries can be recharged down to 25 degrees but at a lower C rate. https://www.youtube.com/watch?v=ywn-vBjKblI
All of this would be great if the cost wasn’t prohibitive. The per watt cost of “reliable” Lithium vs lead acid is close to 5 to 1. Currently I have 4 each 465ah lead acid batteries. At 50% that’s 930 ah available. Those four batteries cost $1600 and with the use of my automatic battery watering system they will last me 6-7 years. quality lithium would cost upwards of $6-8000 or more. Even considering a 10 year life span lead acid still wins the price battle hands down.
When the price comes down sure. Until then we should stick to led acid. IMHO
Wait, discharge to 0%????
That is correct. Modern Lithium Iron Phosphate batteries can be routinely discharged down to 0% SOC without any damage, which essentially doubles the available amp-hr capacity of a similar size lead-acid battery you don’t want to discharge to below 50% of capacity. So that’s twice the available energy in the same size package.
I darn near ran mine down to zero just today. Li’s don’t slowly taper down, they fall off a cliff. The BMS will stop all activity, and then I have to pull the positive cable and let it “reboot” for about 5 minutes before it will recharge. Kinda scary the first 5 times it happens, but you get used to it.
A standard lead-acid battery SOC (State of Charge) meter won’t work for Lithium batteries. You need one specifically calibrated for their nearly flat discharge voltage curve.
I use a Victron BMV 700. Maybe that isn’t the right one, or I’ve not calibrated it properly.
The more I read about converting to lithium ion batteries, the less I want to do it. I’ll just stick to the old fashioned wet batteries that it had at day one. I don’t see enough to be gained by spending the extra bucks so my batteries last longer, and if down the road, I have an electrical issue I will wonder if it is due the expensive changes I made in the batteries, charger, wiring, and whatever else. If I bought a new(er) unit that was born with lithium ion that would be fine.
Point of accuracy, these are Lithium Iron Phosphate chemistry, not Lithium Ion like is in your cell phone or laptop computer. That’s what makes these RV batteries unable to self destruct like those e-cigarettes that blow up in your pocket. 😁
Live Stream is OK by me, but I prefer to watch a U-Tube presentation at a time of my choosing. Thank you.
Hi, Dick. I understand that the presentation will be available to view anytime you want after Mike gets it posted. 🙂 —Diane at RVtravel.com
Yes, you’ll be able to watch Dennis and me millions of time if you like. 🙃
Yay! 😆 —Diane at RVtravel.com
I am a retired electrical engineer so I find this sort of stuff very interesting. I have worked in a refinery, a mine and the IT world. Live stream or YouTube is okay by me. Please cover the use of solar panels with these batteries and also cold temperatures as I live in Edmonton, Alberta. In winter time it does get well below 32 F for most of the winter. That can last 4-6 months with temperatures that can reach as lower than -40 F. No we do not RV then although I do know that some people live in their RVs year round but not many.
I may be ancient, because I don’t like live-streams at all. If it must be a video, I’d like to watch it on my schedule. Mostly I only like videos when it is a movie or someone showing how to do something. I read really well. So, I didn’t know how to answer your survey. I am interested in the subject for my motorhome, but not watching a live-stream.
I’ve done several YouTube live streams and I enjoyed being able to participate in the discussion in chat. The ability to ask questions of the presenter and get feedback in real time is very useful. My opinion is that technical subjects like RV electricity, or in my case, website security, lend themselves well to this format. And to be honest, getting the chance to ask Mike questions about RV electricity makes a live stream really worth your time.
Plus, it will be available on YouTube afterwards, to be viewed whenever anyone wants to see it. Thanks for your input, Kim! 🙂 —Diane at RVtravel.com
I need that too as I may be somewhere without enough signal to live stream.
My biggest concern is the temperature limitations as I spend a lot of time in the high deserts of the SW where nights are often below freezing in winter.
Good overview!
While Solar and Lithium batteries are the preferred way to power for little cost while using it, the switch from Lead Acid batteries to Lithium is a big investment.
We have a 2005 class A RV and have 3 Lead Acid 100/ah house batteries. Those batteries will serve me between 3 to 4 years and cost about $300 every time. When I replace those batteries with 2 Lithium 100/ah I have to pay about $2000. For $2000 I can buy 9 years’ worth of Lead Acid batteries. I’m not even talking about the inverter/charger and BMS here that is another cost. The question becomes will I keep the RV another 9 years or sell it in 6 years, replacing the Lithium with lead-acid?
I know the advantages, the pros and cons of both kinds of batteries but the cost is just too high! If you buy a new or almost new RV it is a good investment for sure.
A recent video on YouTube discussed the cost of running (not buying) Lithium, Lead Acid, and AGM batteries. https://www.youtube.com/watch?v=iy3hga_P5YY
We have a 2010 Damon Avanti 3106 we purchased 2 years ago and in removing the LA batteries this winter for storage they got damaged. We had considered replacing with lithium ones but before we purchased those we first contacted Thor of our intention. They had advised us that the charging system of the motorhome would not work with the lithium batteries (as well as the converter). A bit of a disappointment to us but now are considering getting multiple 6 volt batteries with the reasoning that they should charge a little faster than a couple of 12 volt LA. We are also thinking of going with the AGM style to cut down on maintenance and having to check for water levels etc (not in the easiest place to get at for checking/maintaining). Do you agree that multiple 6 volts is a better way to go than 2 12 volt batteries? Luv your articles-learning so much
#1 Compare the deep cycle Amp hour ratings of both the two 12v and the four 6v.
#2 Will the two or four 6v batteries at your desired deep cycle Amp hours fit in the available space?
# 3 Is any cost difference worth the hopefully increased capacity?
Whatever you do, make sure you buy true Deep Cycle batteries and not Marine Batteries (which are in between starting batteries and Deep Cycle ones.) True deep cycle 12v batteries are often a special order.
Yes, 6v in combination is a more robust setup than 12s. AGM is nice, especially in hard-to-get locations or if you’re just not very diligent about maintenance. Honestly, I don’t know why anyone still buys acid tubs other than cost.
Mike, If you need anything field tested in the boondocks you know who to call!
I’ll keep you in mind…
Have been studying the requirements to convert our 1996 class-A to lithium batteries. Have the basic understanding regarding the Lithium comparable converter, and the use of a DC to DC converter for the house battery. The biggest hurdle right now is understanding how the house lithium batteries and the engine lead aced battery are correctly isolated and how they integrate with the remote battery disconnect latching relays.In short, I would greatly welcome a live stream on the topic.
Great article, though I would have liked to have seen more information on solar charging. I suppose its how the solar controller is configured, if I remember correctly my panels put out over 16 volts or so! Looks like its doable!
Snoopy
Better-quality controllers are configurable.
Solar charging is its own topic, which I’m studying up on. Right now I’m looking for a Solar Panel expert who can team up with me on another live stream. I do know a lot about DC to DC chargers that include a solar panel controller, so that’s a start. Much to do.
Will Prowse on YouTube is the one I’m following for a long time, he has 297K followers, talks 100 miles an hour, and is very knowledgeable about Solar from panels to BMS, inverters, converters and DC to DC.
His channel
https://www.youtube.com/channel/UCoj6RxIAQq8kmJme-5dnN0Q
I have a 48v 100ah Li pack from Relion battery. Wonderful upgrade. I went to a higher voltage because over the years I got tired of dealing with those big, fat wires.
Mike, I have considered the idea several times. What options would you consider to start the generator, What is the cost involved in switching? The average automotive charging system charges at 14.7V with alternator capacity ranging from 125 amp upwards so the alternator charging system in the motor home should be sufficient.
Great question for our YouTube live stream in a few weeks. We’ll announce the day and time of the session soon, and it will be recorded on YouTube so you’ll be able to watch it later, even if you can’t attend the live stream event. Stay tuned…📺
Yes, but it’s still easy to overload a vehicle alternator that’s connected directly to a few Lithium batteries. Consider that some of the 100 amp-hr ones can take up to 100 amperes of charging current. So a pair of them could burn up your alternator. So if you’re going to intermix lead-acid and Lithium batteries, you’ll probably want some sort of DC-DC charge controller. I have this 40 amp version from Redarc which includes a secondary solar panel input. I’ll know more after I get it all hooked up next month. https://redarcelectronics.com/collections/in-vehicle-dual-battery-chargers?gclid=EAIaIQobChMI9u_O5oGh7gIVAf_jBx24nA-XEAAYASAAEgLH1fD_BwE
Long Long Honeymoon (YouTube) recently did video on upgrading their truck alternator. Even though their truck was fairly new it could not handle the additional charging requirements of their newly installed lithium battery bank. https://youtu.be/KTGDCSu1kwI
A DC to DC charger will let you throttle the charging current to something your alternator can safely handle. So a 40-amp controller seems about right. That will completely charge a 100 amp-hr Lithium battery from 0% to 100% SOC in around 3 hours. Of course, if you have a Tow Vehicle you’ll need a heavy duty charging connector and wiring since the 7-way trailer connector is probably only good for 10 amps continuous current.