Hi All,
I'm very close to purchasing a 100Ah LifePo4 battery from LifeBlue for our 21BHS. The initial cost is obviously very high but I'm hoping this battery will be better for us since we are off-grid 99% of the time and can usually only run the generator about 4hrs a day depending on where we are camped. After emails with several manufacturers I have been assured that the WFCO converter in our trailer should be fine for this battery. My main outstanding question is whether the WFCO will allow the battery to charge fast enough since it doesn't switch over to bulk mode until the battery is below 50% charge. And for lithium the voltage doesn't drop hardly any until you are beyond 90% discharged. It's possible I will have to add a separate charger but I'm waiting to see how it goes w/o it.
So... my plan is to relocate the battery to the back of the trailer near the hot water tank. This will keep it in a more temperature stable place (these batteries can't be charged if they are below freezing) as well as in a more secure place. I haven't looked at all into what it will take to relocated the battery.
Does anyone have any input on any of this? :) There's not a ton of info out there for what I am trying to do... most people jumping to lithium seem to be doing it with solar and not using the existing power converter etc.
thanks
tim
Installing a lithium battery in your RV particularly the way you are going about it, is a very bad idea. Why?:
Despite what the vendor says, lithium batteries need very different charging parameters than FLA or AGM batteries. Your camper's converter absolutely will not work. The very fact that the manufacturer say it will work is a very good reason to run, run from this installation.
Also lithium batteries need a load disconnect system in addition to a lithium chemistry specific charger. If lithium batteries get discharged to far, they are toast. I will bet your manufacturer didn't tell you this either.
The ONLY type of of lithium battery system I would consider for an RV is an integrated battery, battery charger and battery management system made from a well known manufacturer. Mastervolt is one of these and they are extremely expensive, well over $1,000 for a 100 Ah battery.
Yes they are lighter than FLAs or AGMs and you can discharge them much more deeply than an FLA or AGM so a 100 Ah battery will go twice as far.
But a simple 100 Ah FLA costs about $100 and an AGM maybe twice that, so at worst $200-$400 for equivalent capacity to a 100 Ah Mastervolt system.
Unless you are desperate to save space and weight or just want to spend a lot of money to be the first kid on your block with a new toy, stick with the tried and true FLA or AGM batteries for your RV.
David
I'm not as convinced as David is that it's a horrible idea. BattleBorn batteries makes a 100AH lithium battery with a built in battery management system that they say is a drop in replacement for lead acid batteries. I've seen many good reviews of these batteries. If I were going to do this myself the key thing I would look at are the voltages of the WFCO converter in the various stages of charging. If they are compatible with the lithium battery I think it's not unreasonable to do it.
I have spoken to several manufacturers about whether the WFCO is compatible or not and I have received conflicting information.
Battleborn states - "Yes our batteries are a drop in replacement for lead acid batteries. What does the power controller set the bulk/absorption and the float to? The bulk/absorption should be set to 14.4V-14.6V and the float should be set to 13.6V or a little lower. "
LifeBlue states - "WFCO is not compatible. It will over charge and then let the battery discharge. We recommend Iota DLS chargers. We stock the 55, 75 and 90 Amp models. You can manually change the charge rate with s switch. Soon, Iota will release an automatic charge module for the converter."
From reading the WFCO manual it looks like it falls in to the parameters as stated by Battleborn. I'm not sure how the WFCO would overcharge the battery though? Is there a way I could have the battery still supply power through WFCO but have a separate charger for the battery? The IOTA charger mentioned by LifeBlue is around $150.
Thanks for the input guys... I need all of it that I can get! And David, not trying to be the first kid with the new toy by any means. Like I said, the pros of lithium for how we camp justifies the cost for me. At least assuming I can get 10 years out of this battery which is the LifeBlue warranty (first 5 yrs full warranty, 2nd 5 years is repair for free but if replacement is required you get 30% off).
If you're off-grid you could attach any charge controller you like in between your power source and your battery. For example, I off-grid camp almost exclusively and I use a portable solar panel attached to a Morningstar charge controller in turn attached directly to my battery. The Morningstar controller is a 4 stage charge controller, bulk is 14.4v, float is 13.7v and equalize is 14.9v. If I went to lithium I wouldn't use this controller because the equalize voltage is a little to high. You said you use a generator, I'm assuming you plug your 30 amp cable into the genny and then into the side of the camper. You could instead run from the genny to a charge controller and then from the charge controller to the battery (If I were going to do this I'd use an inverter generator with nice clean power). Of course this would prohibit using the 120v outlets in your camper but all the other stuff, lights, water pump, fridge on propane, would be fine.
I'm somewhat confused as to why Lifeblue would say that the WFCO isn't compatible if the voltages are okay, perhaps it's the BMS on their battery, I don't know.
I just checked into Battle Born batteries for my off the grid solar system at my cabin. I did not go with them because of the cost and the operating limitations for temperature. Had I been able to use them (and afford them!), I would have also used a lithium battery charger. There are several reputable companies now making them for the lithium batteries, including Progressive Dynamics and Iota. If it was me, investing mega-bucks in lithium batteries would for sure mean providing them the 2 stage charger and voltage they need for each stage. I went with conventional lead-acid AGM batteries that will serve my purpose well and last for many years. Next time around for my camper, I may look again at Battle Born.
A member of the Land Cruiser forum I'm active on just installed a Battle Born battery for his house battery in his Land Cruiser for the fridge, lights, inverter, etc. Along with that, he installed a Redarc battery management system to keep both the house battery and starting battery (which is lead-acid) properly and fully charged. On his recent trip to Baja, it worked GREAT!
Trailer Life magazine has run some recent articles on the popularity of changing from lead-acid to lithium batteries in RVs. Here is on ad for the Progressive Dynamics converter for that purpose, making the changeover easy (and painless for the new battery).
http://www.trailerlife.com/rv-gear/gear/seamless-li-ion-swap/
Thanks Merlin... I'll do some more reading. And Mitch, they said the reason the battery can get overcharged is "Absorb timer can not be reduced to 0-15 minutes.". That doesn't make any sense to me but I know very little about all of this... Battle born seems fine with WFCO and their battery parameters are almost identical to LifeBlue. I reached out to WFCO and their tech told me the only problem using WFCO is that their converter could only get the battery to about 90% charged (which is probably a good thing).
Also, for WFCO to enter bulk mode the lithium battery would almost have to be completely depleted for it to kick in. So... I still have emails out to some places to get more info. With what I know at the moment I would feel ok getting the LifeBlue and trying with the WFCO initially to see how it works. The LifeBlue battery has a bluetooth monitoring app I can use to see how things are going. There's a really good chance I would add a proper charger for it and a battery cut-off switch.
Which leads to another question... could I run the LifePo4 charger directly from rv(house) power? E.g. I run the genny which is plugged in to the trailer like normal and I plug the charger into an outlet in the trailer.
thanks for the help guys!
I'm thinking you couldn't run a separate Lithium charger from house power unless you prevent the WFCO from also trying to charge the battery while the generator was running. I assume that now when you run the genny the WFCO automatically begins charging your battery as well as providing 12 volt power as needed?
Here you go.
https://handybobsolar.wordpress.com/
this guy knows.
I forgot to mention in my last post that the current issue of Trailer Life (May, 2018) has a full tech article on installing lithium batteries in an RV. They installed 2 Battle Born LiFePO4 batteries, a Xantrex programmable charger with a monitor, and a lockable battery box on the tongue. It's becoming a popular conversion and the tech info in the article is excellent.
And I would note that MitchB is correct in his post this morning that you have to be careful to not create a charging loop by hooking up a separate charger to shore power that is already hooked up to the trailer converter!
I have gotten a bit more educated about Li battery systems, particularly those for RVs in the last few days. Here is my take:
The two manufacturers of Li battery systems mentioned here, Battle Born and LifeBlue, both have built in management systems that protect the batteries in case of low voltage, high voltage and other faults. That is good.
The other thing I have read more about is charging parameters for Li batteries. I do believe that the standard Progressive Dynamics converter on our campers does not meet these parameters. PD says that right up front in their website. PD does make an LiFePO4 specific converter that does meet the general requirements and I would definitely replace my existing converter with one of these if I were to install an Li battery.
I do believe that a system with one or more of these batteries and a PD9100L converter will be reasonably safe. Whether it is economical is another question.
David
Hey Guys,
Got a little more info... According to Larry Crutcher who is supposed to be an expert in this area.
"No. Overcharge, holding absorb voltage on after the battery is full, is not protected. That is why you must always use the right charger for ANY battery type, not just Li-ion. The EMS has many other protective features. See attached data sheet.
Beware of some chargers that claim to be Li chargers but are not, like these: https://www.progressivedyn.com/specialty/pd9100l-series-lithium-power-centers/"
So... it sounds like WFCO is no good. Even though BattleBorn is telling me it is and WFCO told me it wasn't capable of fully charging the battery anyway. :-\
I have contacted BattleBorn again to ask them about the overcharging specifically... I'll let you all know what I find out.
If you don't believe that the PD9100L charger is ok for Li batteries then who DO you trust? PD is a major supplier to the RV industry. So is WFCO. Battle Born and LifeBlue must be relatively small companies. Do you trust them more than PD or WFCO? PD has a Li specific converter. WFCO announced a new Li converter design about a year ago, but i haven't seen any evidence of one yet.
With the confusing answers you are getting: the standard WFCO converter will work, the PD Li specific converter won't work, then I guess I go back to my original statement: Go with a known supplier of (marine in this case) electrical systems like Mastervolt. I would trust those guys. They have a 100 Ah Li battery system but it is more expensive than the others. They also make battery chargers, which aren't cheap either, which will charge their Li batteries.
Buying these two critical components from one well known company makes sense to me. But the cost will probably double, particularly for the charger.
David
Yeah, I know David... the conflicting info sucks :|. I'm just quoting exactly what Larry said. I'm going to do a little more research but at this point I'm leaning towards just going the 6-volt route. I do believe lithium would work better for our needs but I don't want to spend that much money with all the conflicting info I am getting.
Maybe if there was "something" I could put between the WFCO and the battery to stop it from charging the battery... according to WFCO the only way to stop it is to disconnect it but then I would have to remember to always disconnect the battery when on shore power.
Ok, just got another reply from Battleborn and although they didn't answer my question directly they did seem to indicate that their BMS would protect the battery from overcharging. Also, on their table listing power supplies they have tested WFCO is one of them... I put the text of the email below.
I have what I think is a great idea. If you guys will send say $300 each I will use the money to buy the components and figure out exactly what all it will take to get this to work. :)
Hey Tim
The BMS protects the lithium cells from getting damaged in several scenarios. From low or high voltage, low or high temperatures, or if there is a short in the system. The BMS will shut off the battery to protect the li-ion cells and the user of the battery from unsafe operating conditions.
The BMS also regulates the amount of power you can take out of the battery. The BMS on our 100 amp-hour battery is rated to 100 amps continuous, 200 amps for 30 seconds and any higher loads for ½ second.
Our BMS also keeps all of the cells in balance. At the top of each charge cycle, the BMS reduces the charging rate in cells that have been topped off first, letting the rest of the cells catch up. This ensures that the cells are always in balance, and maintains the quality and efficiency of the pack.
Thank you
Joey L
info@battlebornbatteries.com
775-525-2472 Direct
855-292-2831 Toll Free
Battlebornbatteries.com
From: Tim Brady <tbrady@outlook.com>
Sent: Friday, April 20, 2018 11:38 AM
To: Battle Born Batteries <info@battlebornbatteries.com>
Subject: RE: lifepo4 battery
Thanks for the help Joey. Was doing a bit more research before I pulled the trigger on this and was told that the WFCO converter could overcharge these batteries while in absorption mode and this is something the BMS is unable to protect against? Basically that being in absorption mode for 15mins was bad for LifePo4 batteries...
Here is what the specs say on our WFCO
"If the converter senses that the voltage is less than 13.2 Vdc it will automatically go in to bulk mode. In this mode the output voltage will switch to 14.4 for a maximum of four hours. If the RV is not being used for 48hrs and shore power is plugged in it will go into float mode and charge the battery with a trickle voltage of 13.2. When the converter senses a demand it will automatically switch to absorption mode which is 13.6 Vdc. The normal mode of operation is absorption mode."
I think that one of issues that makes these batteries more challenging to use (but ultimately better) is that we're used to a dumb battery. We expect that all the management of electricity has to be done by the charger and with these batteries that's just not the case. Battleborn is saying that their BMS will protect the battery. Further, in your case they've tested it on your WFCO charger and say it's fine. If that's part of their warranty then basically you're golden. It becomes a matter of money and not technology.
As I'm typing I'm getting ready to send you the $300 you've requested, please furnish me with your name, address, mother's maiden name, name of your first child, first pet's name, last four of your SSN, favorite color, street you grew up on and name of your first elementary school. As soon as I get all that I will commence mailing you small round copper (or copper looking) disks that maybe, perhaps, are legal currency in all 50 states, at a rate of 2 disks every three weeks until the total amount is fulfilled. :)
Well ok, so here are some facts and speculation.
Unlike FLAs and AGMs, Li batteries only have two charging parameters that have to be met: maximum charging current and float voltage. The batteries charge at either the max the charger will put out or at their maximum allowed charging current until they reach float. Then the charger switches to float and the batteries stay at the specified float voltage. I recall but I am not sure that Li batteries like a little higher float voltage and that is why one of your references said that the WFCO would switch to float too soon and not charge the batteries fully.
I don't think it matters. You might lose a bit of capacity but not the end of the world. The Battleborn BMS will protect the battery from all of the standard faults, no matter what the charger puts out. Plus the WFCO converter at what 45 amps, isn't too much for a 100 Ah Li battery.
$300 contribution, ha!!! I have been dithering for a couple of years whether to scrap my single 70 Ah battery and replace it with two GC batteries to triple my Ah capacity for about $200 total. So far the single battery has served me well.
MitchB: You are absolutely right. Our paradigm is dumb batteries. Li batteries have to be smart with a BMS built in or integrated into the whole system. The charger is just a source of current.
So go for it. But don't expect me to pick up some of the tab ;-).
David
@tbrady,
"Maybe if there was "something" I could put between the WFCO and the battery to stop it from charging the battery..."
If you can find a diode or diode pack that can handle the current, it would do what you suggest. Put the diode between the battery and the WFCO and the special charger between the battery and the diode. That would stop current flowing from the WFCO to the battery while allowing current to flow from the battery to WFCO.
I don't know how the WFCO charging system would react to this scenario.
Sent from my SM-G950U using Tapatalk
Thanks Steve! I will do some research on that...
I've done a lot more research... fortunately this is a very active subject over on the Airstream forum (airforums) and I have learned a ton from there. Here are the key things I have learned-
1. Battleborn seems to be the best option for a "drop-in" replacement even though it's not completely a drop-in replacement. They support the widest range of chargers/converters and their support is outstanding. They were very active on airforum answering questions etc.
2. I could keep my existing WFCO power center and use it with the Battleborn but I will most likely only obtain 90% SoC with it. Also, it seems that WFCO converts are notoriously hard to go in to "bulk mode" and they will take a lot longer to charge the lithium batteries than a charger meant for lithium.
3. To get a better lithium charger (e.g. rapid charging) I could either put a converter between the WFCO and the battery or replace the WFCO power center entirely with a PD4045LIK (which I believe will fit in the access hole) The PD4045LIK is a complete power center is $195 and a basic lithium charger is around $165. The power center would make for a cleaner/simpler install but there is more labor involved. If you had a WFCO 89xx series you can easily replace just the converter section but this isn't possible with the 8735.
4. You would most likely want to add a Victron battery monitor (bmv-700) so you can see the current draw and SoC etc for your battery. This is around $140.
5. You would want to add a diode (or something similar) to prevent the TV battery from drawing down the TT battery while traveling. This seemed to be a common occurrence so people are putting something on the line so that the current can only go in one direction. I think this was about $20-50 depending on exactly what you got...
In reading dozens of pages on this most people were thrilled with the conversion to lithium even though it was more complicated and much more expensive. Battleborn in particular was very well regarded due to how attentive they are and their commitment to being as much of a drop-in replacement as possible.
So... I haven't pulled the trigger on anything yet. I'm going to pop the WFCO out and measure the hole to see if the PD one will fit. And then decide if I want to tackle wiring in a new power center. If I do I will most likely place the new battery in the back of the trailer in the void near the hot water heater (I have the 21BHS). And would probably put the battery monitor above the heating thermostat.
Any feedback/suggestions/warnings is greatly appreciated!
That sounds like a good plan, I'm anxious to hear about the end result if in fact you do go forward especially rewiring to install a new converter. I have the PD 4045 and if a rewire is easy I'd consider swapping everything and getting a lithium battery myself. The additional usable amp hrs would be really nice.
I am a bit unsure of why the TV battery would draw down the a new TT battery while traveling but not the old one. The TV alternator should take care of anything the TV battery needs if you're moving and the voltage of the lithium battery isn't really any different the SLA you'd be replacing. Battery monitor is a good idea whether you change the battery or not in my opinion. I used a $30 Drok unit and it seems to work fine. If i were going to replace it with something a little fancier the Victron would be my choice.
Looking forward to hearing more.
From what I read some alternators would decrease voltage below 14.4volts or something like that and if the lithium was fully charged the flow would reverse and the TT would be pushing to the TV battery. Not sure how prevalent this is but it had happened to a few people and the fix seemed easy so I would probably just wire it in.
More info... I've been chatting with LifeBlue more and they said even on the WFCO 8735 it's possible to wire in a new converter relatively easy. The main difference between it and an 8900 series is that the 8900 series is more modular with converter sitting in it's own little box below the distribution panel etc. The hookup however, is pretty much the same.
Remove converter AC power from breaker.
Locate new converter behind power center.
Connect new converter AC wire to breaker, neutral and ground.
Connect DC output from new converter to bus bar terminals in power center.
Done.
The tricky part is tying the DC output from the new converter to the DC side bar on the WFCO. I'll need to take the back panel off it looks like to get to it... Will let you guys know what I end up doing. I did take a look at AGM batteries but heck, to get the equivalent of a 100Ah Lithium I would spend over $500. I really need something I can put in the trailer as my tongue weight is already high because of all the bicyles we carry there.
I got a 100 AH AGM at Battery Plus for a little over 220$ about 18 months ago on sale. I think you can get one now for about 259$. The brand was Duracell.
The conversion is complete (almost!). I ended up buying the LifeBlue 100AH battery and the IOTA DLS-30 converter with the LifePo4 controller. I went with LifeBlue because of their warranty, the built-in bluetooth battery monitor and the outstanding support from Larry at Starlight solar who thoroughly answered the few questions I had. I've not yet taken it camping but I've tested it at home thoroughly and the results are great. Probably the number 1 advantage is that this battery can be recharged RAPIDLY. I bought the 30amp converter since the WFCO it replaced was a 35amp, with this converter I can pump 30amps an hour back in the battery using my 2200 watt generator. So with a full discharge I can fully recharge it in a little over 3 hours. Another thing that is really nice is the built-in bluetooth, I installed an app on my phone which tells me the state of charge, voltage, current (in/out in amps) and the number of cycles the battery has been through.
The battery is now inside the trailer in some dead space where the water heater is along with the new converter. The existing WFCO converter could easily put back in commission if needed, along with putting a battery back on the tongue if necessary.
The only work left is I want to add a thermal controlled cabinet fan to the compartment all these components are in. According to Larry at Starlight he's never had an issue and hasn't done this but I was testing yesterday with letting the inside of the trailer get hot out in the sun and doing a full battery charge, while doing so the compartment got up to about 101 after about 2hrs of charging.
So, only time will tell if this is worth the high initial cost. If I get as many years/cycles out of this battery as their testing data shows I should I will be thrilled. It will definitely help with our primary mode of camping w/o any hookups.
Sounds really great. Nice work. Report back on how it goes with camper use. I'm pretty sure I'll do this too in a couple years when my batteries have their 7th birthday.
As Merlin said, sounds great! Look forward to more reports.
I'm glad you made the jump and I can offer my experience and research for others. When we got our trailer we wanted solar and knew we would only go with lithium. There are some aspect of lithium that I think are being missed.
For starters, 100ah Li is equivalent to around double or triple of your AGM. Much of this has to do with the ability to be able to discharge down to 0%. Some state that they prefer 20% and either way that's 30 to 50% more usability than AGM. Furthermore, the voltage doesn't drop over time, they recharge fast, and they have a cycle life of 5,000 to 10,000 cycles! So AGM batteries have a cycle of like 500 and a Li battery would pay for itself in the few times AGM were replaced. Yet they would still last 10 to 20 years! It's what they use in a Prius. You can ignore the generator and buy a Li battery.
We went with 3 Renogy Li batteries, installed in the pass through with a fold down enclosure. We have a go power controller and 2000watt inverter. With this setup, all of our plugs are hot. We can plug anything in (yet we put in 12v/usb ports in a few places like the TV). The initial cost is higher, but it pays for itself quickly. You can do more, for a longer period of time, with Li. We would need a lot of AGM batteries to meet our demands (think of the weight!) Li batteries weigh 20lbs each!
It's hard to embrace these new smart batteries, but when you do the math, look at the cost benefit analysis, Li by far comes out on top. Plus, the prices are dropping fast.
Thanks Jason! Yeah, after researching going to dual 6v AGMs and the amount that would cost, plus the fact that I'll only need to run my genny briefly now to stay fully charged made it an easier decision.
Here's a couple of pics, we didn't lose any storage space really. Added the battery switch and the you can see the charging module LED that shows whether it is in bulk or float mode.
I added a piece of HDPE plastic board to have something firm to bolt everything to...
Very nice. Well done.
Ok, officially "done" now. I added a thermal controlled cabinet fan (comes on at 88 degrees and cuts off at 82) and added a 5" vent to exhaust into the bathroom. I ran through the test again and this time the temperature in that compartment never got above 89!
If you decide to do something like this let me know and I can give the specific details of how everything is wired up and the exact parts used. I probably spent 40hrs researching and couldn't find anyone that had changed their power center how I did (most people that did this were able to swap in a new converter to their power center (not possible with the WFCO 8735) but it is quite easy to unhook the converter in the 8735 and use a different one with minimal wiring. The total time to do the wiring and everything else is probably under 10hrs, less if you are not anal-retentive like I am!
How did I miss this thread? I think I was busy doing my own battery upgrade at the same time. I ran into the same dilemma with the stupid WFCO 8735. I ended up just leaving it as is, and installed an additional 50a Cotek charger. They both play nice together. I still get the DC passthru function of the converter when I'm hooked up to AC power, and the WFCO basically disables its charging function when the Cotek is charging.
Love how clean and lightweight your install came out. I went the AGM route out of freezing temp concerns, but now i have 150 lbs of batteries under my bunk which I'm not all that happy about... So i still might switch to your setup at some point. I'm just curious how your setup will work in freezing temps. Like will you have to keep your coach heated all day and night while in freezing temps?
Also.. do you have a link to the fan stuff, and the HDPE plastic board you got? My temps have only got up to 91 degrees when charging at max 50a, but its been really cool where I'm at, and I'm thinking it will get a lot hotter under there come August.
For mounting i just used plywood, but the HDPE plastic board sounds like a better lightweight solution!
That's also cool that those batteries came with a bluetooth monitor. I had to install the Victron monitor with shunt to get bluetooth, but isn't it awesome to be able to check your SOC from outside at the camp fire?! That's probably my favorite part of my entire install.. lol
I probably showed you a pic of my setup already, but if not, here it is..
Hey Gary,
In hindsight I probably should have started this thread under travel trailer mods! Regarding the freezing temps... that was definitely a concern and one of the reasons I put the battery in the compartment with hot water heater. I figure during the coldest of days if we keep the hot water heater on it will keep that compartment above freezing. Also, the BMS on the battery will protect it from charging if the battery is below 32 (which is really the only concern). The app on my phone shows me the battery temp as well.
Here is the HDPE I got-
https://www.amazon.com/Seaboard-Density-Polyethylene-Finish-Length/dp/B00K2QT4P4/ref=sr_1_3?ie=UTF8&qid=1530156250&sr=8-3&keywords=hdpe+sheet+1%2F4 (https://www.amazon.com/Seaboard-Density-Polyethylene-Finish-Length/dp/B00K2QT4P4/ref=sr_1_3?ie=UTF8&qid=1530156250&sr=8-3&keywords=hdpe+sheet+1%2F4)
Here is the cabinet fan etc-
https://www.amazon.com/gp/product/B001BEX52Y/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 (https://www.amazon.com/gp/product/B001BEX52Y/ref=oh_aui_search_detailpage?ie=UTF8&psc=1)
I only ended up using one of the fans as an exhaust to the bathroom. I was thinking that if it was still getting too hot I would use the 2nd fan to blow air in to the compartment. I just cut the black dual shroud thing in half.
Also, seeing how we are so close if you ever get serious about doing this I can show you exactly what I did in person.
Just wanted to give a long term update on this mod... This has been the best thing we have done to the trailer by far. 99% of our camping is without hookups and with the new battery my wife can run all the lights, radio, stove fan etc pretty much all she wants. We usually can go about 3 days before I need to fire the generator up. If I wait until the battery is below 50% SOC the voltage drops enough that it will charge in bulk mode which is right at 30 amps an hour. So basically I only need to run the genny around 2hrs every 3 days which is great.
The one issue I need to address is how to charge this battery with the tow vehicle. Currently it will only charge the battery at about 1 amp/hr (at best).
Well, congratulations on your new Li battery bank. I think I can answer one question and I have another question for you:
If you had FLA batteries, they would charge at about 3-5 amps from the TV at 90% SOC and maybe 10 amps at 50% SOC. This is due to the low voltage from the alternator and the voltage drop in the wiring. The battery is probably seeing at best 13.0 volts particularly at the higher charging current. You can probably improve this by running heavy jumper cables directly from the TV's battery to the LL battery to minimize the voltage drop but that won't work while towing.
Li batteries and their charge management system probably require a higher voltage to charge. That is why your TV won't charge them much. There are a couple of devices you could try to improve this. One would be a simple voltage to voltage converter which could boost the incoming voltage to your batteries up to say 15 volts.
Another way would be with an integrated V to V converter and a three step charger like Sterling makes. But I don't know if these work with Li batteries.
Now to my question: What is your estimated amphour usage in 24 hours? Mine is about 10 AHs but we are very conservative with power use. That lets me easily go three days with my single Group 24 battery and stay at 50% SOC or above.
David
Thanks for the info David! We typically use anywhere from 15-25 amps in a day. We usually run the radio all night to play ocean wave sounds (kids and wife need the white noise) and sometimes we'll run one of the fans all night as well.
I don't pay near as much attention to usage as I used to. The best part is my wife can basically do what she wants without trying to be conservative. We even turn on the awning lights all the time which we never used to do.
Tbrady, Does your Sequoia have a 120V AC outlet?
Quote from: Merlin on August 11, 2019, 03:13:33 PM
Tbrady, Does your Sequoia have a 120V AC outlet?
I think I know where you are going with this question: Use the 120V outlet to power your battery charger for faster charging, right? But most of these are limited to 150W AC which isn't enough to power the LL's converter and will only charge to 10A with a separate low power charger. Hooking up the two batteries with jumper cables will probably charge that fast, with the engine running which is the only way to do it.
David
Quote from: Merlin on August 11, 2019, 03:13:33 PM
Tbrady, Does your Sequoia have a 120V AC outlet?
It doesn't have one...
Ok. Just thought I'd see if what I do was possible (Davidm was correct!). I have a 120V AC outlet in my TV that can power this lithium battery charger to charge my 50Ah Born Free battery at 7.2A all the time I'm going down the road. Over a few hours, that provides more than enough juice to top off the battery, which I use for my electric cooler for travels when not towing. Nifty setup, but it would under-kill for your needs anyway.
https://www.amazon.com/NOCO-G26000-UltraSafe-Battery-Charger/dp/B004LWTHP2/ref=sr_1_4?crid=9RTLSV8NLISR&keywords=genius%2Blithium%2Bbattery%2Bcharger&qid=1565557190&s=gateway&sprefix=genius%2Blithium%2Bba%2Caps%2C147&sr=8-4&th=1
Ok, I see where Merlin was going with this, using a small charger powered from the TV's 120V outlet to charge the batteries underway.
Like I said above you can do the same thing without a 120V outlet using Sterling's battery to battery charger. See https://sterling-power.com/collections/battery-to-battery-chargers/products/battery-to-battery-chargers-waterproof
The B to B charger seems to do what you want: take a low voltage source and boost it and regulate it to charge another battery. The Sterling product info says it works with Li batteries.
You would hook the input to your TV's charging lead then hook the output to your Li batteries. I think that the 20A version is the smallest that they offer. That may work ok, but it will be putting a lot of load on your TV's battery charging circuit which is limited to 30A. If you do this make sure that the TV's battery charging lead only goes to the B to B and not also to the converter where it is distributed to other 12V loads. Those loads may overload the 30A TV circuit when combined with the 20+A load of the B to B.
David
Davidm, Thanks for posting info about the B-B charger. That's got very interesting applications and something I never thought about. It's especially useful for charging 2 different battery types from the same power source.
Quote from: DavidM on August 11, 2019, 08:54:41 PM
Ok, I see where Merlin was going with this, using a small charger powered from the TV's 120V outlet to charge the batteries underway.
Like I said above you can do the same thing without a 120V outlet using Sterling's battery to battery charger. See https://sterling-power.com/collections/battery-to-battery-chargers/products/battery-to-battery-chargers-waterproof
The B to B charger seems to do what you want: take a low voltage source and boost it and regulate it to charge another battery. The Sterling product info says it works with Li batteries.
You would hook the input to your TV's charging lead then hook the output to your Li batteries. I think that the 20A version is the smallest that they offer. That may work ok, but it will be putting a lot of load on your TV's battery charging circuit which is limited to 30A. If you do this make sure that the TV's battery charging lead only goes to the B to B and not also to the converter where it is distributed to other 12V loads. Those loads may overload the 30A TV circuit when combined with the 20+A load of the B to B.
David
I put the 30A Sterling unit in my Transit van to charge an onboard 105AH AGM from the vehicle- it has a couple of AGM profiles to select from- not all specify the same profile. Does a great job.
It can be wired to come on whenever the vehicle is running or it can do a voltage detect on the vehicle battery- when it is above a set point the Sterling comes on to charge whatever it is hooked to. IOW it won't run your power source dead while it charges whatever it is hooked to. It disconnects if the source battery gets too low.
When I originally installed the Sterling my van had a single flooded lead acid battery. I just finished modifying it to 2 ea AGM batteries and need to get into the vehicle PCM to reset it to AGM.
Once that is done I may remove the Sterling but it does have some nice features- such as a remote temp sensor you put on the battery you are charging so it can adjust the profile according to battery temp.
Attached is a diagram that LifeBlue sent me for how to improve the charging but I don't quite understand it. Maybe one of you more smarter folks can dumb it down for me. :) To me it looks like just adding a simple solenoid and running bigger wire? Is it really that simple?
Lifeblue also mentioned using a sterling unit in an email they sent me. Can you send me a link to what exactly you are using ADR?
What the diagram looks like to me is just a way to hook up a house battery along with a starting battery. That's a long-solved need and many manufacturers make a solution for that. What's missing is a way to care for the lithium house battery with a charging profile (correct voltages for bulk and absorption stages and no float stage) to maintain it properly.
As you noted it just looks like larger wiring, #2 instead of the more typical #10 in the TV's charging circuit. That will reduce the voltage drop, but you still are limited to the fixed voltage of 13.5+ that the TV's alternator is regulated to.
David
Quote from: tbrady on August 14, 2019, 02:13:35 PM
Attached is a diagram that LifeBlue sent me for how to improve the charging but I don't quite understand it. Maybe one of you more smarter folks can dumb it down for me. :) To me it looks like just adding a simple solenoid and running bigger wire? Is it really that simple?
Lifeblue also mentioned using a sterling unit in an email they sent me. Can you send me a link to what exactly you are using ADR?
Sure- here ya go> https://smile.amazon.com/gp/product/B071DMV7PF/ (https://smile.amazon.com/gp/product/B071DMV7PF/ie=UTF8&psc=1)
Do not use the 30a Sterling b2b with your TV's standard battery charging circuit. It will blow its 30a fuse. It needs a separate high amp circuit as is shown above.
Sterling's UK website shows a 20a model, but I haven't seen them for sale in the US.
David
Blow the 30A fuse? Could be- I power mine off the 60A connection on the driver's seat pedestal. The Transit has 1-3 connections- each rated 60A.
Mine had 1 so I added the other 2 to make 3.