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Converting to a 12V 200AH Lithium battery
My motorhome has 400W of solar in two strings of two panels each, feeding two 6 volt, 210 AH Costco golf cart batteries. I’d like double the usable capacity to 200 AH with a single 12 volt, 200 AH LiFe battery. I do have the space for four golf cart batteries, but I don’t trust the battery slide tray to carry 240 lbs of batteries (60 lbs for the LiFe battery). The conversion requires a LiFe battery ($1000) and two MPPT controllers ($100 ea, one for each string). The inverter/charger has a LiFe setting, so no changes needed there.

My main question is about the LiFe battery that looks like a good choice: the Renogy 12V LiFe unit with Bluetooth monitoring, 200 amp max continuous discharge, a BMS with all the usual protection including low-temperature charging disconnect - $1000 with shipping. The specifications:

12V 200Ah Lithium Iron Phosphate Battery w/ Bluetooth
  
I’m assuming the Onan 4kw generator won’t have any problem starting from this battery, as it can supply 240 amps for 15 seconds without tripping the over-current protection.

1) Does anyone know of a better choice than the Renogy?

I haven’t chosen the two MPPT controllers, each of which will be used with two 100W, 7 amp max output solar panels in series. The outputs will be in parallel on the battery. It’d be nice if they had remote indicators that could be mounted near the inverter/charger control panel, but built-in displays would work.

2) Any suggestions for the MPPTs?

I believe the LiFe battery is safe if the alternator is directly connected to the battery, though it probably doesn’t get fully charged that way. My concern is the alternator may harm itself trying to charge a large LiFe battery, but I haven’t found any definitive information on charging a LiFe battery directly from a standard (2004) E450 alternator. I’ll skip alternator charging for now by disconnecting the OEM charge cable in the engine compartment. But still ...

3) Does anyone know if the E450 alternator can handle charging a LiFe battery directly?
                                                                  
2005 Jayco 24SS
Re: Converting to a 12V 200AH Lithium battery
Reply #1 –
Eric,

Lithium coach batteries need an interface between the truck chassis alternator and the lithium batteries. This adjusts the charging voltage from alternator to the lithium batteries.

When having all my solar/lithium batteries  installed at AM Solar, they placed a Victron Cyrix-Li-Ct relay between the alternator and the solar/lithium charging system. Everything works perfectly. Not sure if this will be appropriate for your LD model year.

The Cyrix-Li-Ct relay can be purchased directly from AM Solar or possibly from Victron.

Hope this helps.

Kent
2015 27' RB "MissB.Haven"
Re: Converting to a 12V 200AH Lithium battery
Reply #2 –
$999 is a very low price for a 200 Ah LiFePO4 battery. A pair of Battle Born 100 Ah lithium batteries--a popular low-end choice--will run you $1,600 and up, last time I checked. A single 200 Ah Victron "Smart" lithium battery costs about $2,000. Two 100 Ah batteries from Lithionics, a high-end manufacturer, cost upwards of $3,000. Given the extremely low price, I have to wonder where Renogy is cutting corners. Another concern: they have a reputation for poor customer service. If anything goes wrong...

I'll give Renogy credit for including Bluetooth in a battery this cheap. That means you can get a look at what's going on inside the battery, and (I assume) upgrade its internal software if necessary, using a smartphone app.

For what it's worth, the screenshots below show the kind of information you can get from Victron's and Lithionics's iOS apps. Renogy's app requires signing up for an account, so I haven't been able to see what information it provides. Battle Born, lacking Bluetooth, doesn't let you access this kind of information. I wonder how long before competition forces them to add that ability?
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Converting to a 12V 200AH Lithium battery
Reply #3 –
3) Does anyone know if the E450 alternator can handle charging a LiFe battery directly?

No the E450 alternator can not handle charging the LiFe battery directly.  Li batteries have very low resistance and will allow an excess of current from the alternator to flow to the Li battery which will result in your alternator overheating.

In order to move away from the lead acid battery to a LiFe battery you will need to replace the Lazy Daze factory battery isolator circuit with a DC to DC charger.  The DC to DC charger will regulate the amount of current flowing from the alternator to the Li battery to prevent your alternator from overheating.

You will want to chose the current capacity of the DC to DC charger so that it does not exceed the available excess charge capacity of your alternator.
2002 M-23 Twin King & 2016 Subaru Forester tow car
Re: Converting to a 12V 200AH Lithium battery
Reply #4 –
Several of us have gone lithium. There are four problems to solve.

1. Freezing temperatures.
2. Solar charging.
3. Converter charging.
4. Alternator charging.

Everyone I know has the lithium batteries inside the heated space. Batteries with heaters are now available.
Solar chargers with a lithium profile are now available.
Converters with a lithium profile are now available.
We all solved the alternator charging in different ways.

You have two and three solved. One and four to go. Have fun, you will enjoy lithium.
Harry 2006RB
Re: Converting to a 12V 200AH Lithium battery
Reply #5 –
Quote from: hbn7hj  - 
Several of us have gone lithium. There are four problems to solve.
...
4. Alternator charging.
...
We all solved the alternator charging in different ways.
One way is to simply disconnect the charge line to the house battery, and do without alternator charging; I'm aware of the DC DC charger method, and that would be easy to do; I've heard of alternators with current limiting ability, but that appears more expensive and difficult than the DC DC charger. What are the other methods normally used?
2005 Jayco 24SS
Re: Converting to a 12V 200AH Lithium battery
Reply #6 –
Quote from: Eric Greenwell  - 
One way is to simply disconnect the charge line to the house battery, and do without alternator charging; I'm aware of the DC DC charger method, and that would be easy to do; I've heard of alternators with current limiting ability, but that appears more expensive and difficult than the DC DC charger. What are the other methods normally used?

I retained the original batteries and left the original isolator and batteries untouched. Lithium charging is done only by solar and generator. I can use the lithium batteries to charge the flooded lead acid batteries with a DC to DC charger.

It is not a simple system. It has been working very well since 2017.

Lithium charging from the generator peaks at 120 amps so doesn’t take long. 14.3 volts is full.

2003 Roadtrek hybrid battery system - Class B Forums
Harry 2006RB
Re: Converting to a 12V 200AH Lithium battery
Reply #7 –

Hi Eric;  I'm in the process of converting to LiF batteries.  I chose S.O.K. batteries but I haven't actually hooked them up yet. (any week now)  Two at $1029 each. Rated at 206 AH. That gives 412 AH total. I have crammed both into my present battery box, including a (intended for water holding tanks) 12 VDC sheet heater.
   #1; The heater has an internal thermostat. It has been tested sort of. It was cold enough in San Diego to have it come on at 40 degrees, but just for a few seconds. It is between the batteries and the outside compartment door. Soon to be insulated, and (I hope) air and water tight.
  #2; Solar   I replaced my old solar panels. Now 350 Watts. The R3000i can be programmed manually to supply a higher voltage. 14.2, 14.4 or 14.6 volts. I picked 14.4, but I haven't tested that yet.
  #3;  I replaced my converter last year with a Progressive Dynamics.PD4655 Li.  LiF compatible. Swapping a jumper changes it to the higher voltage, profile to match LiF.
  #4;  I got a Renogy 60 Amp Dc to DC converter. It has jumper switches to select LiF voltages and charging profile.  There is a D+ 12v signal to enable charging from whatever voltage the alternator puts out, to (up to) 60Amps at 14.6 V to charge the LiFs. A 12V signal applied to the LC input cuts that in half to 30A. (LC=low current)  I'm sure my older '99 E350 chassis can handle that, and I will have switches at the dash to control the Renogy box.  No charge at start up. 1/2 charge at first, then full charge at 60A if the batteries need it. My alternator is rated for 130 A. With all external lights (not headlights) converted to LED current drain is minimal to run the fuel pump, ignition, instruments.  The A/C clutch (with interior air handler fan) , and headlights are certainly a concern. Can't remember if I have an auxiliary electric fan for cooling. The chassis battery can handle that short term. Renogy makes a 20A/10 (LC)  and 40A/20(LC) version.
    My power demands hopefully won't go up too much, so the increased solar when available should do most of the charging I need. Sometimes the sun doesn't shine.  I don't plan to be in cold weather very often. The SOK batteries got good reviews. (The Marine version is too big, and more $$).  It does have an internal low temp shut off, but no Blutooth. Steel battery cases.   12V 206Ah LiFePO4 Lithium Iron Phosphate Battery Pack | SOK Battery USA.

   The Renogy DC/DC-30 can both handle Solar 15A with MPPT and 15A from the alternator.  Amazon.com: Renogy 12V 30A DC On-Board Input MPPT Battery Charger for Gel,...  so two of those might do the job for the solar you have set up now.   "The Renogy Dual Input DC-DC On-Board Battery Charger with MPPT is designed to charge your service battery to 100% from two inputs: solar and alternator."
    Another month and I should have it all working. The 'TK has very little expansion space, which complicates even simple things. I'm still adding a 2KW TSW inverter and more.        RonB

As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB
Re: Converting to a 12V 200AH Lithium battery
Reply #8 –
How have people solved the heat dissipation challenge of the DC-DC converter from the engine alternator to the lithium batteries? It needs to be mounted on metal, not plastic or wood, due to how hot it can get. That means it needs to live underneath on the truck frame or engine compartment wall, not in the battery box or on the internal wood frame.

2013 27’ Mid-Bath
2005 Honda CR-V
Re: Converting to a 12V 200AH Lithium battery
Reply #9 –
I use a Morningstar Sunsaver MPPT, which will control 2 100W panels aimed full sun, or does fine with my 300w flat on the roof. It only has a couple LEDs for readouts, but can hook to optional full panel display. A pair of these with their readouts should work for you. They are extremely rugged and fully programmable with a computer and software. Mine is currently hooked to a pair of Battleborn 100AH batteries.

Steve

p.s. the Renogy 100AH battery uses soft-pack cell technology - may be fine, but uncommon. Will Prowse has a youtube teardown of it. Not sure if the 200AH would use the same technology...
2004 FL
2013 Honda Fit
Re: Converting to a 12V 200AH Lithium battery
Reply #10 –
Quote from: Andy Baird  - 
$999 is a very low price for a 200 Ah LiFePO4 battery..... Another concern: they have a reputation for poor customer service. If anything goes wrong...
$1000 for a 12V 200AH LiFe battery isn't cheap anymore. There a numerous brands offering them for less than $700 now, and that might be why Renogy has gone from $1299 to $999 (at least during the sale). I am disappointed to hear their customer service is poor, but at least they are an established brand, unlike the slew of brands in the <$700 range.
2005 Jayco 24SS
Re: Converting to a 12V 200AH Lithium battery
Reply #11 –
Quote from: Keith Sweitzer  - 
How have people solved the heat dissipation challenge of the DC-DC converter from the engine alternator to the lithium batteries? It needs to be mounted on metal, not plastic or wood, due to how hot it can get. That means it needs to live underneath on the truck frame or engine compartment wall, not in the battery box or on the internal wood frame.

I use both the Kisae DMT 1250 and DMT 1230. They have internal fans and work well. Note they also have solar controllers.
Harry 2006RB
Re: Converting to a 12V 200AH Lithium battery
Reply #12 –
Quote from: RonB  - 
   The Renogy DC/DC-30 can both handle Solar 15A with MPPT and 15A from the alternator.  Amazon.com: Renogy 12V 30A DC On-Board Input MPPT Battery Charger for Gel,...  so two of those might do the job for the solar you have set up now.   "The Renogy Dual Input DC-DC On-Board Battery Charger with MPPT is designed to charge your service battery to 100% from two inputs: solar and alternator."
It's very intriguing, but there are quirks, especially the low solar cut-off voltage, according to this user:
https://www.amazon.com/gp/customer-reviews/R2E5IU7P078XDP/ref=cm_cr_dp_d_rvw_ttl?ie=UTF8&ASIN=B093BB3PCV
As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
2005 Jayco 24SS
Re: Converting to a 12V 200AH Lithium battery
Reply #13 –
There is a YouTube by "I'm not lost, I'm RV'ing" with a review of the SOK 206. They have a gray 27 LD.  https://www.youtube.com/watch?v=Oez7zrxBwAc
    As mentioned by Steve, Will Prowse has a video about the SOK 206 here:  https://www.youtube.com/watch?v=GRTmvjcLXxs
    For Keith, the 60A Renogy DC/DC voltage booster is at worst 90% efficient. Running at it's maximum rate of 750 W, that is dissipating 75 watts. It has two internal fans and will shut down if it gets too hot. 75 watts isn't all that bad. I don't plan on running it at full power often, more in the 30 A range using the low current mode. (LC) That would dissipate more on the order of 40 W. Like a 40 watt light bulb.  I have a temperature monitor near it to watch what is going on. It is mounted on aluminum rails. (More on that later.)
    Many videos have the Renogy box mounted in areas that wouldn't be good for excessive heat problems. Compartment bays similar to our storage areas with the felt liner walls, etc.    RonB
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB
Re: Converting to a 12V 200AH Lithium battery
Reply #14 –
Quote from: Eric Greenwell  - 

I believe the LiFe battery is safe if the alternator is directly connected to the battery, though it probably doesn’t get fully charged that way. My concern is the alternator may harm itself trying to charge a large LiFe battery, but I haven’t found any definitive information on charging a LiFe battery directly from a standard (2004) E450 alternator. I’ll skip alternator charging for now by disconnecting the OEM charge cable in the engine compartment. But still ...

3) Does anyone know if the E450 alternator can handle charging a LiFe battery directly?
                                                                  

Battleborn claims their batteries can be connected to the alternator without harm.
If retaining the original isolator wiring and isolator (or relay), I doubt if the 10-gauge wiring can pass enough amperage to damage the alternator.  This could make the DC to DC converter an unnecessary expense.
Ford has increased the alternator output through the years, 130-amp to 225-amps, depending on the model year.
Watching our LD's battery monitor, I have never seen our 2003's 130-amp alternator charge the coach battery at over 45-amps, where the PD9270 converter will charge at up to 68-amps, depending on how depleted the battery is.

With the large difference in battery costs and a large number of manufacturers, as Andy pointed out, will the vendor disappear in a couple of years?
Most of these batteries are built-in Asia, from unknown companies. The odds are many will be gone in a year or two.
Paying more for a brand name, with a track record and good customer service, may be the cheapest way to proceed.

Larry





Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Converting to a 12V 200AH Lithium battery
Reply #15 –
Quote from: Steve  - 
p.s. the Renogy 100AH battery uses soft-pack cell technology - may be fine, but uncommon. Will Prowse has a youtube teardown of it. Not sure if the 200AH would use the same technology
The picture of the 200AH on the Renogy site shows what look like prismatic cells, not the pouch cells of the 100AH unit Prowse had.
2005 Jayco 24SS
Re: Converting to a 12V 200AH Lithium battery
Reply #16 –
"Battleborn claims their batteries can be connected to the alternator without harm."

Having spent a lot of time reading Battle Born's datasheets and manuals, and after watching an extended interview with their CEO, I get the feeling that they are pushing the "just drop it in" angle pretty hard, glossing over any potential problems. Maybe I'm a cynic, but I would not take that claim too seriously.
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Converting to a 12V 200AH Lithium battery
Reply #17 –
Quote from: Larry W  - 
Battleborn claims their batteries can be connected to the alternator without harm.
If retaining the original isolator wiring and isolator (or relay), I doubt if the 10-gauge wiring can pass enough amperage to damage the alternator.  This could make the DC to DC converter an unnecessary expense.
I'll do the conversion, then measure the alternator amperage with a mostly discharged house battery. If the current is less than, say, 50 amps, I'll stay with the direct charging from the alternator. As for brand names, Renogy is a US company that's been around for 10+ years, long enough for me to think they will be around 5-10 years from now.
2005 Jayco 24SS
Re: Converting to a 12V 200AH Lithium battery
Reply #18 –
Quote from: Larry W  - 
Battleborn claims their batteries can be connected to the alternator without harm.

They are correct, it won’t harm the battery but if you connect an alternator to a low resistance load for any length of time something is gonna pop. At the very least aim a heat gun at the alternator. I don’t think my LD has a circuit breaker on the charging line and the wire is very heavy. Properly instrumented you could give it a try.

We could all learn something.
Harry 2006RB
Re: Converting to a 12V 200AH Lithium battery
Reply #19 –
I disconnected the alternator from the coach electrical system the day AM Solar completed my system and warned me of the potential alternator damage.

That was September 2015, and it turns out that I've never needed the alternator boost.  On very rare occasions I've topped up from the 4K generator or shore power, the panels suffice 98% of the time.

Give it a try without the converter and see if it's needed, if so it's simple to add later.

Steve
2015 TK
Re: Converting to a 12V 200AH Lithium battery
Reply #20 –
Quote from: Steve TK  - 
I disconnected the alternator from the coach electrical system the day AM Solar completed my system and warned me of the potential alternator damage.

That was September 2015, and it turns out that I've never needed the alternator boost.  On very rare occasions I've topped up from the 4K generator or shore power, the panels suffice 98% of the time.

Give it a try without the converter and see if it's needed, if so it's simple to add later.  Steve
Excellent plan! I'll do it.
2005 Jayco 24SS
Re: Converting to a 12V 200AH Lithium battery
Reply #21 –
Apropos of what Steve said: Long ago I disabled Skylark's isolator and substituted a big Blue Sea switch. When turned on, it combined the house and engine batteries, and set a little red LED to flashing as a reminder. (It may sound like a dumb idea to disable an automatic system and go manual instead, but I've seen and read about too many isolator failures. That heavy-duty switch was never going to fail.)

Anyway, my point is this: I found that I very rarely had any need to turn it on. Just as Steve said, my solar panels (500-600 watts on the roof) took care of the batteries most of the time, with very occasional help from the generator. If I were putting lithium batteries in a midbath today, I wouldn't even bother hooking up the line from the alternator.

That said, I am planning to install a Victron Orion 30A DC-to-DC charger in my Airstream, powered by a line from my truck. Why? Because unlike my LD, the Airstream has no built-in generator... and I haven't yet gotten around to installing solar panels on the roof. This setup will let me use the truck as a generator in an emergency.
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Converting to a 12V 200AH Lithium battery
Reply #22 –
Hi Andy;  The difference in price was a few bucks between the 40 and 60 A Renogy boost converter. With the low current mode (LC), and the ability to manually control (dash switch, defaults to off) any charging (+D), It also isolates the chassis battery and house battery.    The 2015 LD's and possibly earlier did away with the voltage drop diode isolator.  They come now with a large rated relay. 300A capacity, 500A surge, that parallels the batteries when the engine is running. Much higher tech, and modern designed relays have improved a lot since the 'old days'. 
   The wire going to the battery box in my TK is #4, and I need to add a return ground chassis wire that doesn't go through my battery shunt.  The output of the DC/DC booster does go through the shunt, and the grounds are isolated between input and output. 
   The Victron Cyrix combiner   Cyrix Battery Combiners - Victron Energy  has a mechanical relay that turns itself on and off by a microprocessor measuring time and voltage. The problem with that is there is no monitoring of the alternator current, and the entire engine/chassis system voltage changes to provide charging to the house batteries. The house batteries need 14.6 volts to charge, not good for the WLA chassis battery. I assume it shuts off (opens up) when the engine is stopped.
  The BattleBorn isolator  LiFePO4 Battery Isolation Manager (BIM) | Battle Born Batteries   is also a mechanical relay that turns itself on and off on a fixed duty cycle. Well the duty cycle does check voltage output of the alternator / chassis battery / house battery condition.  Also the engine and entire chassis voltage goes up and down when the relay cycles. It costs almost as much as the Renogy booster. 
    Both the Cyrix and BattleBorn BIM are much smaller, and can take 'under the hood' conditions. Maybe I should have gone that way. (not that there is much room available under the hood). If the Renogy doesn't work the way I want, I can switch things around. A work in progress. 
    Should the right used MB show up, I'm learning a lot on how to do this all.  (Maybe again.)  When it is all working properly I'll post a full description of what worked, with pictures.     RonB
    p.s.  The added weight of new panels, wiring, booster and inverter is still under the 34 pounds of removed lead acid batteries( 65x2 vs. 48x2), old solar panels, (48Wx3 vs. 100Wx5)  and removed battery drawer slide.  Weight change about nil.
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB
Re: Converting to a 12V 200AH Lithium battery
Reply #23 –
This discussion points out a dilemma for me. At the moment, our alternator and batteries are connected via a diode battery isolator. This type has a separate terminal for the alternator output which has no voltage present with the engine off. I have a modified-sine-wave inverter wired to power the fridge on AC while driving. This inverter is active through a relay to the chassis battery connection of the isolator, which is triggered by a connection to the alternator terminal of the isolator. This allows the inverter to remain off until the alternator is spinning and generating enough voltage. Since all the lithium - alternator interfaces require connecting the alternator output to the chassis battery, I would have to move my trigger point to the ignition switch - less desirable for several reasons.

For the time being, I will play wait-and-see on adding any of these aftermarket devices, with the possible option of simply tripping the 100A breaker in the battery box to eliminate alternator charging. Two Battleborn BBGC2 mounted in the existing battery tray.

Steve
2004 FL
2013 Honda Fit
Re: Converting to a 12V 200AH Lithium battery
Reply #24 –
Hi Steve;  Your 2004 is pretty close to my '99.  Under the hood is the wiring and fuses for the entertainment radio, and CB radio.  They are connected to the #4 wire under the hood connected to the diode isolator house battery terminal, which isn't powered by the chassis battery, but is to the house batteries.  I got the reverse camera from LD that is wired to be on in 'accessory' essentially just when the engine is on. I used that wire to power my dash USB and TST tire monitor. That wire supplies power to the reverse lights. I think another switch in series at the transmission selector turns those on. You could use that wire, under the steering wheel, to power an isolator relay. I have to remember not to use the other accessory position, since that enables the power windows. One cat was smart enough to use the window switch to escape the motorhome. (Long chase ensued at midnight at Hurkey Creek in 40 degree weather).
   I plan to run the refrigerator on a small 400W inverter, powered behind the side access panel by the wire LD supplies (8 ga) to that area from the house battery.  It would be enabled by that same signal.  How do you keep the 'fridge from trying to light the gas flame when it loses 120 VAC from the inverter?  Seems like that would defeat the purpose when filling at a gas station.  I was going to turn off all 12v to the fridge during fueling to keep it idle.  RonB.
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB