What You NEED to Know About Adding Lithium Batteries to Your RV

well welcome back to my shop here and my 2001 Beaver Patriot Thunder class a diesel motor home and today I want to try to demystify installing lithium iron phosphate batteries on a modern RV or a used one now although I will be talking about motorized RVs and motor homes there are some points that are vital to uh towable units too like a fifth wheel or a travel trailer now I just very recently like 2 days ago installed this 460 power lithium iron phosphate house battery right here from Vader don't pay attention to that and I replaced my four or AGM 6vt lead acid batteries I know there's a lot of channels out there and a lot of information available online to explain how lithium batteries work but I'm going to try to simplify it for a modern RV first things first this is a lithium iron phosphate or Li po4 a battery that I installed lot of rvers and do-it-yourselfers do want to switch to lithium batteries but there's a lot of I wouldn't call it misinformation out there but there is some fear out there that lithium batteries can cause an uncontrollable uh fire but even though these are still considered lithium batteries the lithium iron phosphate right there L Fe P4 is almost adverse to actually starting on fire or causing fire so fire safety is not something you have to worry about if you go with a lithium iron phosphate battery this why a lot of uh rvers are now going to these lithium iron phosphate batteries also this obviously is not an electric vehicle or handheld power tool or rechargeable flashlight so the added weight that you'll find in iron on these batteries is not nearly as much of a concern as it would be in something handheld like this battery here and while these batteries here may cause a fire if you did puncture them or charge them incorrectly fire is not a concern with lithium iron phosphate batteries okay so that's the first thing I wanted to talk about with lithium batteries in an RV lithium iron phosphate batteries won't be a cause of fire you won't have to worry about that on your RV okay very important I think a lot of that misinformation stems from uh back in the day when you had to make your own lithium battery out of different modules and create your own system where you were basically hacking a battery and using it to your own needs as far as RV use goes but these are off-the-shelf manufactured batteries for RV use now but in keeping with that first problem of your homemade batteries would be the second one issue which is the the BMS a lot of people are worried about uh charging the batteries correctly uh with an established system that was not intended for lithium batteries now don't get me wrong a lithium battery does have a different charge profile than a lead acid battery battery an AGM battery or a dry cell battery however most modern manufacturers for the lithium batteries have a smart BMS or battery management system that can accept most charging from most systems the real limitation comes from the fact that lithium batteries need a higher voltage charge to get a 100% top off charge on them than a standard uh RV converter inverter gives them even right here it says if charging voltage is lower than 13 .8 the battery power cannot be fully charged so a modern BMS system built into these batteries is its own little uh brain computer Gateway that's going to take whatever charging is coming in and regulate that to the battery itself monitoring each individual cell for over current or over temperature situations and adjust the charging accordingly the problem is if the voltage isn't high enough you won't get to 100% you might only get to 90% charge on your uh lithium battery unless you upgrade to a charger with a lithium profile on it now most towable units like this fifth wheel or a travel trailer will have a converter or battery charger in the basement area or under a cabinet and usually looks like this box right there and there you put out about 13.6 volts DC so just underneath that uh top off that we need so if you have a towable with a convert like this uh new one's about $300 to $500 with that lithium profile on it wouldn't be too difficult to change out if you really wanted to however on a motorized unit like my motor home right here that has a built-in inverter charger this Magnum uh 2800 inverter changing out that entire inverter for a lithium profile uh that's about $2,500 and probably not worth it just to make sure that you get that extra 10% of charge on your batteries CU you just can't upgrade uh with software on these things that would be too easy though I think you can with the victron system but not with the Magnum or or uh Xantrex or some of the more common inverter Chargers you'll find out there so what I'm telling you is uh you do not have to upgrade your charging system to a lithium uh compatible uh battery charger from your motor home or your towable if you don't want to you just won't get to 100% fully charged on your lithium battery it may not be a bad thing either because most lithium battery manufacturers don't want you to keep it at 100% all the time so what is an rver or a do it-yourself you're supposed to do if they want to get uh 100% out of those lithium batteries without upgrading to a very expensive uh charger or inverter setup more than likely if you're upgrading to lithium batteries for energy storage you're probably putting solar on the roof or have solar on the roof I would would recommend that uh you take that money you would have spent on a new charger or inverter and invest in solar a little bit bigger solar than you thought you were going to use because with at least 500 watts of solar on the roof and fairly inexpensive MPP charge controller like this one I have from renery it will have a profile for charging lithium batteries in a modern setup so you get that last 10% of charge on your house batteries from the seller above for a fraction of the cost of a new Inver or a lithium compatible converter in the basement don't misunderstand me we can change the settings on this inverter even though it doesn't have um a lithium setting on if I go to battery type I can go to custom right here and then I can make some changes to it lithium batteries might come with an owner's manual to tell you what the settings they recommend would be so on mine it's just recommending between 14.2 and 14.6 yours might be different but if I go to my custom settings right there uh basically 14.6 is where we want it to uh be we go 14.5 I don't think it's going to matter uh float anything below 13.6 should be fine uh 13.5 is fine for me and equalize that's as low as I can get is 14.6 and that's basically it now I'm only really showing you this because I know a lot of people would ask me this question but my point point is this the modern BMS systems on all these modern lithium batteries really won't require any of this they do all the calculations for you as you don't really have to worry about a charge profile like you would have a few years ago so that's the second thing to know about modern lithium iron phosphate batteries is you really do not have to completely upgrade your charging system to match to lithium profiles okay it's important to know that does lead us into the third most important thing to know about converting your RV to a lithium battery and while there are over a handful of reasons to upgrade to lithium batteries as it is be it for weight savings uh low maintenance energy density or of course relocating your batteries completely inside a sealed compartment where you don't have to worry about ventilating hydrogen gas or acid spilling one of the better features about lithium batteries is that they can charge very quickly unlike lead acid batteries like this if you completely discharge them it could take theoretically two days to fully charge lead acid battery but if you completely deplete a lithium battery you can charge these very quickly in a matter of three hours so if we look at the specs on my uh Vader 460 amp hour capacity battery it can accept 120 amps or current running into it to charge it now while towable units like this fifth wheel right here do receive a charge from their tow vehicle through the sway plug umbilical right here usually that's maxed out about 30 amps of draw on it but on a motor home like my Diesel Pusher there or this Georgetown right there the house batteries are always wired up to the chassis alternator for charging and even on a great big huge alternator like this 200 amp alternator you might find on my motor home 120 amps straight to those batteries will start to overheat that alternator after like 3 hours of charging it let alone the smaller Al you'll find on these Ford Chassis for the class a motor homes or the class C motor homes so this is an important thing to know about we don't want to burn out your alternator with a lithium battery and that could happen if you don't plan for it now this is not a in-depth tutorial about every motor home out there uh cuz they're all a little bit different but every motor home out there will have a battery isolator because they'll have a house battery and Chassis batteries they want to keep separate unless they're charging both of them off the engine Eng when it's running so on my setup right here I literally have a battery isolator right above this is a solid state uh diode basically in there with a heat sink on there alternator goes in the middle and you have a house battery your engine battery that separates the charge out over here I have what's called an auxiliary start but we'll talk about that later however these solid state uh isolators fell out of favor about 2002 and almost everything went over to the uh charge solenoid right there or auxiliary start solenoid right here your motor home might have a charge solenoid that looks like this to charge a house battery when the engine's running or like this or a big boy like this okay currently there's two common methods to alleviate concerns about burning out your alternator on your motor home if you upgrade to lithium batteries now I don't have an example of the uh most popular method which is to get a DC todc converter which will basically just be a program able choke to limmit the amount of current that the uh lithium batteries can accept or could pass through you do have to uh set it up and program it and understand how the system works it is a little bit more complicated and in my opinion a lot more expensive and more difficult for uh both the DIY and the rvtech that may not know you put that in the second and easiest method in my opinion is to get a smart relay there are a few different ones on the market but this is going to be the most common one from uh uh Precision Serv right there really it just has a logic built into it that's both a timer and a choke it's really not too different from the uh bird uh bidirectional isolator relay that you got from intellitech that you might find on a lot of uh motor homes out there especially diesel pushers if the coach batteries or the house batteries start drawing too much amperage it will open up this uh relay right here and everything still goes to the chassis batter is just fine now I do realize that is a oversimplification of the performance and the logic of this it does have a timer built into it too where it will cycle on and off but basically uh if the house batteries the lithium batteries are drawing too much power from the alternator it will disengage this for a set of time and then re-engage it again as it draws too much again it disengages it and then as a battery starts coming up in uh uh voltage or uh capacity uh it stops drawing as much power over time and where that's going to be a real big problem is uh if your lithium battery is near nearly completely discharged that's where it's going to accept a lot of uh amperage anyways but even on a uh intellitech system right here with a bird it would click and unclick the house battery charge solenoid too so this really mimics the whole thing but it's a little bit smarter and set up for lithium batteries where this is not set up for lithium batteries at all it just has different parameters in it Al so it's not the same thing so obviously I'm going to be going with this method right here to protect my alternator it's the simplest method it's fairly do it yourself even even though mine's will going to be a lot more complicated than most people's out there so like I said I have uh the battery isolator right here I'm going to have to move the alternator to the chassis side right here on the same side of this post right there and then the house side I will be moving to the coach battery side right there now for added difficulty uh this also has ignition ground and uh signal I don't have that my Solid State uh battery isolator so I'm going to have to run that too but luckily I do have ignition right over here just off of my board so I'm going to have to disconnect my batteries both the house batteries and the chassis batteries to wire this in there's really not a lot of safety on any of these battery cables they're all directly to the batteries okay that and that's the important one all right now the chassis battery is disconnected we'll do the same on the house battery too all right so I have labeled the chassis battery the alternator and the house battery back there I'm just going to disconnect all these battery cables and we'll get the other thing hooked up and I'll try to explain everything else is going on up here all right so here's the original solid state battery isolator should be able to see A1 and two so alternator battery One battery two basically it would just uh split up uh the voltage default to the chassis starting battery and go to the other battery if there was enough power to go to that side too just a big doodes are in there to uh regulate it all and that's a heat sink around it the other thing I removed was the echo charger this is the original one that came with the uh RV it's a pretty solid state unit too just what it sounds like if the house batteries were charging it would charge the chassis batteries with a little trickle charge to it also I'm I'm just going to remove this for I don't Simplicity basically we won't worry about that for now and then the next thing up here is going to be the uh auxiliary starter battery boost solenoid cuz chassis battery's going up past that anyways too so this we'll get into on uh very shortly but I remember moving this too so this just has a ground wire R to it there's going to be signal from the dash and then we just have house and batteries and then this is a solar hookup from the original solar there's ground and that was the ground that came off the uh boost solenoid there all right and then this is the ignition lead that will activate that charge solenoid that I tapped off of the uh rear start switch so before we go any further need to connect these uh chassis batteries back up all right so I have the new uh relay smart relay installed right there this is just the ignition uh feed from uh the switch over there and we do have it hooked up I made a new cable if you guys are asking that's what that is for now that's why I told you to ignore my short one that was just a uh another temporary solution we've went ahead and removed the battery isolator solid state one we removed the solid state Echo charger and we've removed the old battery boost relay or solenoid more on this later all right so let's go ahead and take a look at our batteries right now we're on ground down there positive there 12.45 46 and then on the house side which is there 13.4 huh from this relay right there I didn't know it was B directional so I'm wondering if cuz I do have solar and it is charging if I go to the chassis battery now look at that we're charging the chassis battery so this is bidirectional I did not realize that was bidirectional so that eliminates the need for those down there which I did want to talk about later too first things first I will have to get a little bit off of uh the house battery so that we can see if the engine's charging it read 99% charged we're at uh what's our voltage 13.34% let's go ahead and convection stupid clock so let's bake it to 360 in there so look at that we're drawing 20 5 amps currently right so in the app right here it is showing 2117 amps drawing out and our voltage should drop to 12.8 12.9 well that's preheating I'm curious about one thing back here we're still charging the chassis battery or not or if we dropped out yeah so it did drop down so that's good so that's actually a pretty good selling point that this might be better than a DC todc uh converter I was unaware it was bidirectional that's kind of cool I didn't want to use this or this to charge the chassis battery because their tolerances aren't quite in theory with uh lithium batteries because they're set up to pretty to start charging at about 12.8 and of course that batter is fully charged at about 13.2 or so so even if the lithium battery wasn't being charged uh its voltage is so high that it would start charging the chassis battery off the coach battery and run that down to 12.7 or 6 which is pretty low for that lithium battery battery so that's why I want to took him out I'm sorry the convection oven is ready at this point it's nice and hot in there so if I pull out the app and I take a look at it right now it looks like I'm at 86% our battery voltag is 13.16 now so I think this should be good enough at this point to start the engine and see how we're doing now the 33.4 7 amps is I'm still running the refrigerator and of course my kitchen lights are 110 lights along with the wall sconces there there and there let me go ahead and start this up all right so our battery is charging at 14 Vols the house it just clicked in at 13.5 look like it's pulling 106 amps off the alterated to charge this bring up the app it only shows 60 amps are currently going to the battery the rest is going to be powering up the refrigerator the lights and the 12vt in fact you can see the inverter's pulling about 27 28 amps by itself and we Dro down to 13.6 on the chassis battery now I understand this is not really a fair test to see if the alternator is going to get burned out or that relay is going to work or not because a lithium batteries draw the most when the battery is fairly depleted so 10 to 20 to 30 % depleted that's where it's going to really Spike that's what lithium batteries are great for they can charge quickly at 86% it's not going to draw as much as you might expect to have so we probably won't be having a problem with the alternator here I'm not doing a complete breakdown of this whole system here I'm just trying to elaborate what you do need to worry about if you do upgrade to lithium batteries with a motor home but now just because people do want to see it we'll go ahead and put it into high idle there's a cat so we have to do it this way hold down [Music] resume so even at high idle of I'm about 1200 RPMs right now it hasn't affect the current whatsoever maybe it helps cool the alternator off a little bit more with a faster fan speed on the alternator but that's about it all right so we've covered that base now it is important upgrading your motor home house battery to lithium that you do consider the alternator from your motor home engine okay and so a DCT todc converter or a smart charge relay is going to be what you want to make sure you do cover important on that I do agree to this the BMS is not smart enough to affect your alternator okay so think it through the last thing I do want to talk about is your battery boost on a motor home and this only applies to motor homes has nothing to do with towables fifth wheels trailers things like that traditionally RV manufacturers took advantage of the fact that on a motor home you have a set of chassis batteries to start the engine and a house battery for all your interior lighting and appliances so that if your chassis or engine starting battery went dead you could jump start the motor home engine off the house batteries you cannot do that with a lithium battery that is one of the true limitations of a lithium battery now the BMS built into it will limit current flowing out of it now on the back battery I installed its maximum continuous discharge current is 250 amps okay after that it'll shut the battery down if you know anything about starting an engine especially a diesel engine they require a lot more uh cranking amps on them I think each one of these is about 1,000 cold cranking amps so put together we have about 2,000 cold cranking amps to start my massive caterpillar C12 turbo diesel engine here and if you do the math it's simple math 2000 is a lot more than 250 amp so you cannot start the engine with the lithium battery after you install it now I do still have my signal right here that we haven't hooked up and I will hook it up to the signal uh post down there and on my RV it corresponds with this momentary switch that looks like a battery you can click and hold that down that'll link the two batteries together a lot of other motor homes out there it might say auxiliary start or Mom switch or emergency start on it that will link the two batteries together you cannot start the engine can I tell you this one more time you cannot start the engine off your lithium battery at this point so all this switch will do in the future is you can push and hold it down to charge the chassis batteries off your house batteries and it'll take a 30 minutes to an hour of holding that down to hopefully get enough charge on the chassis battery to start the engine this time if that's not going to work for you what I would recommend you do is invest in a freestanding battery charger to bring with you in your basement that way you can start your generator or plug into an extension cord and charge your chassis batteries the old school way so there I have it hooked back up again to the signal up there hopefully you guys can hear it let me go ahead and lock it in place I had to use something a little bit more aggressive than paper ground again right there 13.18 13.1 there we go so it is charging the chassis battery off the uh coach battery now and then that'll disengage it but that was pretty much everything I wanted to show you guys uh concerning the uh the four important things to think about when you're switching your RV from a lead acid battery to a lithium battery uh there's a lot of uh information out there and I don't think a lot of people cover these four important items so hopefully that helps somebody I got a lot to put back together so let me just clean my mess here now what I think I'm trying to say which might be unpopular to a lot of people out there is that the modern BMS of a lithium iron phosphate battery is already built up to be the Gateway for the charge of the battery anyways so if the charger does have a lithium profile set up for it it still has to go through the BMS built into the battery itself all the lithium profile is doing is raising the voltage enough to get 100% charge out of the battery you're still going to want to go to your battery manufacturer's uh specifications they're probably going to say they want to keep it about 80 85% charge most of the time they don't really want you to go to that 100% and the only way to to get that 100% is going to be with that lithium charge so you're not going to damage your batteries with a normal RV charger or an inverter you just won't get it up to 100% uh I just don't want people to uh not get a lithium battery because they don't they look and say well I'm going to have to buy $2,000 for a new inverter I'm going have to buy a whole huge setup with a bus bar charge control Gateway uh Bluetooth connectivity for all of this uh just so I can have a lithium battery I don't want you to have that as a limiting factor for it uh there are a lot of I think there are a lot of overly complicated battery setups that people are putting into RVs you have to have a an engineering degree or electrical engineering degree to understand the pathway for all of it and as an RV owner or a do-it-yourselfer I don't think it's as vital as uh a lot of people are letting on this isn't the uh the world of 5 years ago where you didn't have off-the-shelf features with a BMS on it the modern BMS is doing all the work for you don't try to overthink this or over complicate it is my advice of course always check with the battery manufacturer I can tell you that Vader right here basically said your AOK if you want 100% you're going to have to get a lithium charge profile out of it but that's why I did my cost saving and I used my MPP charge controller with a lithium profile on it like I said it might be a little bit of an unpopular opinion so blow me up in the comments if you think think I'm wrong but I think I'm right and don't forget these have a BMS built into them also and we trust those and treat them like trash or make sure or make sure it is some or make sure you do or make sure you do get that installed okay important on that I will agree it is important or make sure you get that installed

Channel: AZ Expert

Views: 100,817

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Id: -3sHpgQK2R4

Length: 28min 56sec (1736 seconds)

Published: Tue Feb 06 2024