By Mike Sokol
Dear Readers,
You (the people) have spoken. Last week I published a guest essay by Dennis Wieske from Progressive Dynamics, one of the leading manufacturers of RV battery chargers and power centers. To read that article, please take a look HERE.
Page Contents
The big question (no, the answer is not 42)….
After his informative article, I posted a poll asking if you would like to attend a YouTube livestream event in a few weeks with both Dennis and me, allowing you to text us questions about Lithium battery charging in real-time. Here’s how you responded to the poll (you can’t vote on this screenshot):
By the numbers…
As you can see from the numbers (and the numbers don’t lie), 2/3 of those responding (66%) said you would definitely watch this event (either live or a recording), with an additional 18% thinking about it. I would call that a definitive positive response. So we now have a tentative YouTube livestream date and time of Tuesday, February 2 (Groundhog Day) starting at 8 p.m. Eastern time, which is 5 p.m. Pacific time. But don’t worry if you can’t attend the livestream event in real-time as it will be recorded and archived on YouTube forever.
Why is this important?
Since so many campgrounds are overcrowded, and reservations may already be completely booked through 2021 for many of them, many RVers are looking at boondocking as a way to go camping. However, if you’re on your own there’s no pedestal to plug in for AC power. So Lithium batteries, solar panels and quiet inverter generators are important technologies that can help keep you happy and safe when providing your own power during boondocking.
Isn’t it as easy as Plug ‘n Play?
Some resellers of Lithium batteries imply you can just drop a new Lithium battery into any RV without considering the rest of your electrical system. Seems too good to be true, doesn’t it? That may be true in many cases with a modern converter/charger rated to work with Lithium batteries, but never assume anything.That’s because as great as they can be, Lithium batteries require that your converter/charging system is capable of providing the correct voltage and current for best battery performance.
And it’s true that if you do everything correctly, Lithium batteries are good for 3,000 to 5,000 charge/discharge cycles. And yes, you can indeed discharge them down to 0% SOC (State of Charge) without any damage, essentially doubling the usable amp-hr capacity of your current lead-acid battery which you shouldn’t discharge below 50% SOC.
However, if you simply drop a Lithium battery into your RV as an upgrade without checking your RV’s battery charger compatibility, you can create problems ranging from the inability to fully charge your battery to 100% SOC, all the way to destroying your expensive new Lithium batteries rather quickly from desulfation pulses designed for flooded-cell lead-acid batteries.
What to do?
Well, Dennis is the expert on Lithium-rated charging systems for your RVs, and has already fielded hundreds of questions from the field, so I’m excited to learn even more about this important topic. Please add any more of your questions below so we can prepare for our YouTube livestream event on Tuesday, February 2nd, 8 p.m. Eastern Time. And we’ll also be able to take live text questions from those of you watching in real-time.
Future Shock
If this goes as planned, I’ll try to find other experts in a variety of RV products and technologies who I can interview. So please pass this link on to everyone you know. This coming week I’ll include a link to this YouTube stream here so it will send you a reminder of when to log into the show. So check back soon and ask your questions below.
Sign up on YouTube for this live streaming event by clicking HERE.
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.
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##RVT984
Most of the talk on converting an RV to Lithium is focused on the inverter system. After a lot of research, I think I have a handle on that. My concern and need for information is for the alternator and charging system of my Class A Motorhome while on the road.
Thanks, Roy Frazier, Birmingham, AL
My RV uses 6 glead acid old cart batteries — how many lithium 12 volts can be charged in parallel connection and maintain balance charge when full?
(My off-grid solar home uses 2000 amp hours 12 volt system with windmill and inverters so must remain 12 volt batteries. I assume I cannot switch that large a system to lithium batteries in parallel. But the RV would work….?)
How do you find out if your battery charger is compatible?
Would appreciate if you can address this in the live stream. My PD 4645 converter has a Wizard Mode Button for manual override of the Charge Wizard. It can be set to Boost Mode to provide 14.4 V to the battery. Can this be used for lithium batteries?
Alternatively, I have a document that explains how to unplug a cable from the circuit board and replace with a jumper to set the output voltage to a constant 14.4 volts. Can you comment on this? Thanks
This is not specifically related to RV’s but could be! It has to do with wiring two or more lithium batteries in series. For me it means two in series for my 24 volt trolling motor on my boat? Haven’t read much about these batteries in series.
As I understand they are not well suited for series connections because of the
BMS, internally the wire that passes the current between the poles is not adequate for series, does this question make sense? Thanks
Don Barylski
Should read senses current flow internally
Mike,
Quote on the Progressive Dynamics Website,
Can I Use My Present Progressive Dynamics PD9200, PD4000 or PD4500 Series Lead/Acid Units With the Charge Wizard to Charge My Lithium Battery?Yes, if you are willing to live with an expensive battery that is only partially charged. The Normal Output voltage of the …. Series voltage provides only 13.6-volts and a full charge voltage for Lithium needs to be 14.4 – 14.6 Volts. The …. Series Charge Wizard will initially jump to 14.4-volts in the Boost Mode when first connected to 120 VAC power and will remain there until the battery voltage reaches 13.8-Volts, then automatically drops …..This lower charge state will not damage your battery, but will eliminate most of the advantages you paid for.
My understanding with Lithium will last longer is used in a 20 – 80% SOC. Isn’t the above scenario ideal for longevity? The PD4000 charges my lithium to 90%.
Thanks Mike,
When adding a Lithium smart inverter/charger to my RV does the I/C isolate all the components? Specifically, is the
AC source isolated from the AC outlets in the RV (doesn’t back feed if AC supply goes away but still passes through AC / produces AC as applicable)
Battery isolated from DC outlets in the RV so they can be shut off when approaching 0% SOC
Engine DC system isolated from House battery or is battery isolator and/or dc-dc charger required
Are multiple dc charging sources isolated from the invert charger, or managed? Ie: solar input, alternator input, I/C, or are these DC inputs (and loads) really only managed by a BMS?
Sorry so long. All the hobbyist / diy people out there describe different components that are applicable to them. I am trying to ‘big picture’ what is applicable to my needs (wants).
Thanks again.
Mike, how to select a DC to DC Charger compatible with Lithium and protecting a OEM alternator from overheating would be helpful. Looking forward to the discussion.
Yes, that’s a great question which we’ll cover.
Hi Mike, my rv has the WFCO 8500, not lithium compliant, but offers an upgrade with the 8550 that is compliant. Is this an easy replacement? What about the Sprinter alternator? Thanks
Paul Holden
Hi Mike, I keep seeing & hearing that you can discharge those Lithium batteries to 0% SOC. That has left me somewhat confused as with my AGM batteries I only have 50% available of the total capacity. So when I reach 0% SOC, I actually still have 50% left in my AGM batteries & they need to be charged!
So My question in Lithium batteries is at 0% SOC are they actually “O” voltage or is it is the the same as AGM SOC batteries? Well I’m confused easily, hopefully Mike can figure out what I mean!
Snoopy
Snoopy,
What happens with a Lithium battery is that if it’s rated for 100 amp-hr capacity, you can actually count the watt-hrs of discharge (yes, I’ve done this) and the SOC meter on the Briter Products battery ticks down to 0% SOC as you approach 100 amp-hrs of power used. On the other hand, for a 100 amp-hr AGM battery with a voltage monitor it shows around 50% of energy used once you reach an actual 50% State of Charge. While a Lithium battery isn’t cheap, you do get to use the full amount of rated amp-hrs you paid for thousands of times without damage. But as I’ve noted elsewhere, you can’t use a flooded cell or AGM battery level meter to show how much power (amp-hrs) is left in your Lithium battery. Instead of a gradual voltage drop (like a flooded cell or AGM battery) Lithium batteries sort of drop off a cliff once they approach 0% State of Charge.