LiFePO4 Install

dreadlocks

Well-known member
The battery that came in my new adventure toy hauler (InTech) was crap, was a interstate 60aH RV battery the dealer slapped in, literally the cheapest thing you can get.. In our first few boondocking weekends it hardly lasted a day before I had to fire up the generator (Honda 2200i) for hours to get it back to 100% so we could go through the night.. Pretty much every time we went out we deep discharged the poor bastard and it was shedding amp hours quickly.. this was not going to last even our first season and I just started wiring up my gmrs repeater and vhf radios knowing I didnt have the capability to use em.

We dont have very large energy needs, I had a 100ah AGM battery in a milk crate I used with a 100w solar panel to keep my ARB fridge going throughout or adventures w/my lil tent trailer.. it'd last for days without energy input, but it didnt last long with the abuse we gave it.. after 3 seasons it was done.. Now I just plan on adding an efficient propane heater as a critical load with that same fridge, they are nearly diametrically opposed, when fridge has to cycle often im likely not using heater, and if heater has to cycle often I can put fridge outside where it likely wont cycle much at all..
I do have extra secondary loads like lights/fans/radios/numerous battery chargers that will gladly use any excess energy I happen to collect.. but I had those before and managed consumption just fine with the help of an accurate energy meter.

I was planning on ponying up $400 for 150lb of lead batteries (Trojan 6v) to get 110ah of usable capacity, but instead opted to spend a little more than twice that on lithium, If it lasts 2x as long its a bargain for all the extra benefits I'll receive, if not its still likely worth it if you can afford it IMO.. I am just really starting to outfit this rig and being able to not only save a bunch of weight on the tongue but reduce it from this crap I got it with was worth a lot to me.. Ive got room for a ton of unobstructed solar over the axles.
It weighs in at only 30lbs, being 99% efficient on energy input and output means less losses charging it, and being able to bulk charge to 100% is greatly reducing the amount of sunlight or generator time needed, it gladly takes 30A even when its 95% charged, and with an internal BMS they can give you 100% capacity without the kind of abuse that would do to lead..
I'm going with fixed solar panels on roof, 350 watts worth.. Should be able to recharge from cut off to full in a few hours of direct sunlight, and with as much time as we spend in forest environments thats about the best we can hope for.. with oversized solar setup and a battery that can recharge in a fraction of the time, I hope to avoid the need for alot of battery capacity or using the generator frequently.. When I do need to use the generator, I wont feel as guilty for making noise and burning gas since I can get it done in a few hours instead of all friggin day.

I got lucky and had a manufacturer defect with the 35amp Progressive Dynamics fuse box in my camper, they were easy to work with and when I asked them if I could take the opportunity to upgrade to the 45amp Lithium power center they had they said sure, no problem and upgraded me for free.. wow totally badass, thanks PD! I really like the new fuse box over the old one, for starters it has 12 circuits instead of 5.. most are unused right now but that wont last long.. it also has support for an external DC cut off switch that made wiring up to an external LVD (100A Victron Battery Protect) a piece of cake, otherwise if the charger is cut off from the battery when voltage gets low there'd be no way to charge it back up w/the generator. I also needed the extra space for a breaker so I could hardwire my fridge in separately from outlets, this way when I run the inverter it wont be powering the fridge with AC when there is no shore power.

Sadly the new fuse box didnt fit w/out modification, the hole needed to be about half an inch taller, that was easy few mins w/a jig saw, but unfortunately it made contact with my power cable box that was directly behind it.. well this was nothing a bit more sawing could not work around:
IMG_20180729_112655.jpg

also without any internal power, there's also no ventilation, lighting and of course air conditioning.. but we keep on working through the heatstroke sporting our headlamp.

I also install a master disconnect switch, so I can ensure there are no loads on the battery when I have it in storage.. in the end everything looked nice and clean. I decided to install a green 120v led into the top of the fuse box, as an indicator we have shore/generator power.
IMG_20180801_175705.jpgIMG_20180801_175717.jpg

In the battery compartment I put a new battery box in and move it to a new location, it dont need ventilated anymore so I get to reclaim a bunch of storage space.. I chose BattleBorn because they were well reviewed, warrantied and price was fair IMO (could save a couple hundred and import one from china, with no warranty and lower output ratings). I also way oversized the cabling for a couple of reasons, first of all the main connection points for power/ground would be on the other ends of the Battery Monitor (Ground Shunt) and the Battery Protect (Solid State LVD) so I wanted absolutely minimal voltage drop so these connection points would be just as good as the points on the battery.. Secondly because I soon intend to wire in a 1200VA Inverter that can handle surges more than 2x that, so it needs to be capable of delivering 200A of power for up to 30s, and 100A continuously. A 200A inline fuse was installed directly to the battery terminal, even though the battery's BMS will supposedly stop a short circuit in 1/2 a second, a fuse will react even faster.

IMG_20180801_173927.jpgIMG_20180801_175549.jpg

I still need to run a wire from the relay output of the battery monitor to the power switch on the battery protect, this way I can have the battery monitor shut down the power once its 80% discharged.. Lithium does not start shedding voltage until its almost discharged, so even though the battery protect is programmed to cut off at 12v, the lithium battery will still be mostly discharged at that point.. I'll keep 20% in reserve to prolong the lithium battery, and if push comes to shove and I need that extra 20% (say it cuts off heat in middle of night) its a few clicks on the battery monitor to turn the LVD back on.. then it'll keep running til it hits that 12v and the battery protect decides the reserves are gone.

IMG_20180801_185622.jpg

Now that this rather expensive project is complete, I'll move on to installing a Propex 9k btu heater to extend the season.. then I'll probably put the solar panels up and then get the inverter so I can make coffee in the morning without going out operating machinery (firing up genny)

I've done a bit of dry run testing here at home and have been very impressed, with typical loads the battery monitor says I have several days of capacity left instead of several hours.. I'm taking it out this weekend for first real run but I expect it to still have plenty of charge on our way home after a weekend @ sand dunes, finally..
 
Last edited:

luthj

Engineer In Residence
What size BB battery did you select? What are the charge voltages for the PD charger? How long does it hold the absorb voltage before dropping to float? A high float voltage, and a long absorb time (or to high of voltage) will reduce the batteries life. Treated well you can get 5+ years without much trouble. The BB has an integral disconnect for low/high voltage. Its best used only as a last defense, so the external disconnect is a good idea. Though 12V might be a bit low? I would need to check the BB discharge curves to be sure.

For others in the market, the Duracell (Deka) GC2 batteries are a great deal, and have good life for around 250$ a pair last I checked.
 

FlipperFla

Active member
The battery that came in my new adventure toy hauler (InTech) was crap, was a interstate 60aH RV battery the dealer slapped in, literally the cheapest thing you can get.. In our first few boondocking weekends it hardly lasted a day before I had to fire up the generator (Honda 2200i) for hours to get it back to 100% so we could go through the night.. Pretty much every time we went out we deep discharged the poor bastard and it was shedding amp hours quickly.. this was not going to last even our first season and I just started wiring up my gmrs repeater and vhf radios knowing I didnt have the capability to use em.

We dont have very large energy needs, I had a 100ah AGM battery in a milk crate I used with a 100w solar panel to keep my ARB fridge going throughout or adventures w/my lil tent trailer.. it'd last for days without energy input, but it didnt last long with the abuse we gave it.. after 3 seasons it was done.. Now I just plan on adding an efficient propane heater as a critical load with that same fridge, they are nearly diametrically opposed, when fridge has to cycle often im likely not using heater, and if heater has to cycle often I can put fridge outside where it likely wont cycle much at all..
I do have extra secondary loads like lights/fans/radios/numerous battery chargers that will gladly use any excess energy I happen to collect.. but I had those before and managed consumption just fine with the help of an accurate energy meter.

I was planning on ponying up $400 for 150lb of lead batteries (Trojan 6v) to get 110ah of usable capacity, but instead opted to spend a little more than twice that on lithium, If it lasts 2x as long its a bargain for all the extra benefits I'll receive, if not its still likely worth it if you can afford it IMO.. I am just really starting to outfit this rig and being able to not only save a bunch of weight on the tongue but reduce it from this crap I got it with was worth a lot to me.. Ive got room for a ton of unobstructed solar over the axles.
It weighs in at only 30lbs, being 99% efficient on energy input and output means less losses charging it, and being able to bulk charge to 100% is greatly reducing the amount of sunlight or generator time needed, it gladly takes 30A even when its 95% charged, and with an internal BMS they can give you 100% capacity without the kind of abuse that would do to lead..
I'm going with fixed solar panels on roof, 350 watts worth.. Should be able to recharge from cut off to full in a few hours of direct sunlight, and with as much time as we spend in forest environments thats about the best we can hope for.. with oversized solar setup and a battery that can recharge in a fraction of the time, I hope to avoid the need for alot of battery capacity or using the generator frequently.. When I do need to use the generator, I wont feel as guilty for making noise and burning gas since I can get it done in a few hours instead of all friggin day.

I got lucky and had a manufacturer defect with the 35amp Progressive Dynamics fuse box in my camper, they were easy to work with and when I asked them if I could take the opportunity to upgrade to the 45amp Lithium power center they had they said sure, no problem and upgraded me for free.. wow totally badass, thanks PD! I really like the new fuse box over the old one, for starters it has 12 circuits instead of 5.. most are unused right now but that wont last long.. it also has support for an external DC cut off switch that made wiring up to an external LVD (100A Victron Battery Protect) a piece of cake, otherwise if the charger is cut off from the battery when voltage gets low there'd be no way to charge it back up w/the generator. I also needed the extra space for a breaker so I could hardwire my fridge in separately from outlets, this way when I run the inverter it wont be powering the fridge with AC when there is no shore power.

Sadly the new fuse box didnt fit w/out modification, the hole needed to be about half an inch taller, that was easy few mins w/a jig saw, but unfortunately it made contact with my power cable box that was directly behind it.. well this was nothing a bit more sawing could not work around:
View attachment 463767

also without any internal power, there's also no ventilation, lighting and of course air conditioning.. but we keep on working through the heatstroke sporting our headlamp.

I also install a master disconnect switch, so I can ensure there are no loads on the battery when I have it in storage.. in the end everything looked nice and clean. I decided to install a green 120v led into the top of the fuse box, as an indicator we have shore/generator power.
View attachment 463768View attachment 463769

In the battery compartment I put a new battery box in and move it to a new location, it dont need ventilated anymore so I get to reclaim a bunch of storage space.. I chose BattleBorn because they were well reviewed, warrantied and price was fair IMO (could save a couple hundred and import one from china, with no warranty and lower output ratings). I also way oversized the cabling for a couple of reasons, first of all the main connection points for power/ground would be on the other ends of the Battery Monitor (Ground Shunt) and the Battery Protect (Solid State LVD) so I wanted absolutely minimal voltage drop so these connection points would be just as good as the points on the battery.. Secondly because I soon intend to wire in a 1200VA Inverter that can handle surges more than 2x that, so it needs to be capable of delivering 200A of power for up to 30s, and 100A continuously. A 200A inline fuse was installed directly to the battery terminal, even though the battery's BMS will supposedly stop a short circuit in 1/2 a second, a fuse will react even faster.

View attachment 463770View attachment 463771

I still need to run a wire from the relay output of the battery monitor to the power switch on the battery protect, this way I can have the battery monitor shut down the power once its 80% discharged.. Lithium does not start shedding voltage until its almost discharged, so even though the battery protect is programmed to cut off at 12v, the lithium battery will still be mostly discharged at that point.. I'll keep 20% in reserve to prolong the lithium battery, and if push comes to shove and I need that extra 20% (say it cuts off heat in middle of night) its a few clicks on the battery monitor to turn the LVD back on.. then it'll keep running til it hits that 12v and the battery protect decides the reserves are gone.

View attachment 463772

Now that this rather expensive project is complete, I'll move on to installing a Propex 9k btu heater to extend the season.. then I'll probably put the solar panels up and then get the inverter so I can make coffee in the morning without going out operating machinery (firing up genny)

I've done a bit of dry run testing here at home and have been very impressed, with typical loads the battery monitor says I have several days of capacity left instead of several hours.. I'm taking it out this weekend for first real run but I expect it to still have plenty of charge on our way home after a weekend @ sand dunes, finally..
Wow! Sounds like a really nice system and a great installation job. Im sure it will give you years of dependable service.
 

dreadlocks

Well-known member
The Lithium Battery: https://battlebornbatteries.com/shop/12v-lifepo4-deep-cycle-battery/
The PD Fuse box/charger is PD4045: https://www.progressivedyn.com/specialty/pd4000l-series-lithium-power-centers/
Victron Battery Monitor is BMV-712: https://www.victronenergy.com/battery-monitors/bmv-712-smart
Victron Battery Protect is BP-100: https://www.victronenergy.com/battery_protect/battery-protect

The PD Charger provides a constant output of 14.6v, there is no float charge, its at bulk/absorb voltage continously.. it relies on the battery's internal BMS entering protect mode once its fully charged.. from the BattleBorn manual:
For your Bulk/Absorption stage, the ideal voltage is between 14.2v-14.6v. This range will allow the battery to fully charge any higher then this and the built in BMS will send the battery into a protect mode. Our batteries do not need to float
The Victron Battery Protect's highest cut off voltage is 12v, and yeah thats still too low for my liking.. Hence why I'll wire the Victron Battery Protect to the Victron Battery Monitor, because it calculates remaining capacity based off consumption not voltage.. I can configure the the Battery Monitor to trigger an external relay if various conditions are met.. here is a sample screenshot (demo unit because I'm not home right now)

Screenshot_20180802-120216.png
 

luthj

Engineer In Residence
That continuous 14.6v will dramatically cut battery life if you spend a good amount of time plugged in.

If you must continue to use this charger with no float option I strongly suggest reducing the charge voltage to 13.8 or so volts . You will have slightly less available capacity but your battery will last much longer.


BB, By saying that the batteries do not need to float they're not saying to continuously charge them. Instead they are saying that you do not and should not float charge these batteries once full. Once they reach the absorb voltage for more than a few minutes the charge should be stopped and not restarted until battery has just discharged a significant amount.

As far as low SOC or voltage cutouts I recommended a low-voltage cutout as its pretty reliable on lithium due to the fairly consistent discharge curve. It can take quite a while to get one of these battery monitors properly calibrated for lithium batteries. As they can sometimes drift substantially from your actual SOC.
 

dreadlocks

Well-known member
yeah thats what my instincts were telling me, and the reason for the master disconnect.. also from what I've read its best to store Lithium batteries at partial charge instead of fully charged.. The only times it'll be plugged in continuously is at home, and I'll discharge the Lithium to ~50% and then pull out the key.. I'll leave the power hooked up so I have lights and stuff.. and then a day before we leave for a trip I'll turn the battery back on, let it charge fully and give the battery monitor a good recalibration in the process, then unplug it from shore power.

We almost never have shore power the way we camp at dispersed sites, but if I do I'll disconnect the battery entirely.

There is one nice thing about the Constant Current/Constant Voltage charger, it dont make noise when its got a very small load on it.. the previous box would whine if it was just powering the LED lights.
 

luthj

Engineer In Residence
Okay. Correct about the partial state of charge storage, somewhere between 40 and 60% is ideal. As long as you're aware that you shouldn't leave the batteries sitting at 14.6 volts for any extended period you will be okay probably.

I would adjust your charger down to 14.2V. No real capacity reduction there, and it will reduce aging.
 

john61ct

Adventurer
I believe your BMV can be configured to trip a relay at charging voltage (negotiated between charge source and battery) reaching X volts.

For me I would set that at 13.8V, but you may prefer higher.

Ideally would disconnect charger via its switch, or cut off its input, rather than isolating batt from charger output.

12V is fine for LVD, and you still have BB's internal cutoff as a final resort.
 

dreadlocks

Well-known member
@john61ct I hadent thought about that case, but yeah I think it can.. and I suppose minimum latch time can go high enough it would not re-engage charger for a good while after it had reached charge voltage.. but it could still sit there and cycle between charging as it goes from resting voltage to charge voltage.. Think it not only needs the high voltage cut off, but it needs a low-voltage inverted cut-on to complement it.. Disconnect Charger @ 14.4v, Connect Charger @ ~13v (or whatever 25-50% discharged is)

I'll look closer to see if there is a pot I can adjust for charger voltage, but I do not recall seeing one.. I was taking the 14.6v number off the PD spec sheet but if my memory serves me correctly my BMV is reading 14.4v output, so the adjustment is probably just hiding from me.

here is a discharge graph for the battleborn

I think 12v shut off is safe, they used an 11.8v cutoff in these tests.. but im not sure exactly how much is left at 12v as its a steep drop @ 12v, it seems like it will only be a few % left.. think the best way to find out at this point is to put load on it and calculate how many amp hours I consumed to get to 12v.
 

john61ct

Adventurer
13V is pretty high, especially for high-amp loads.

Fully adjustable LVDs are cheap at low amps, can dedicate per circuit or even appliance, have less essential / thirstier stuff cut out higher.

Note that Voltage does not correspond that well to SoC, high-currents in or out will distort from resting.

If you've installed and use the BMV properly, manually resetting 100% at the top,

https://marinehowto.com/programming-a-battery-monitor/

https://marinehowto.com/installing-a-battery-monitor/

its programmable relay could be triggered by whatever SoC you like on the way down. Personally I think anything higher than say 12.3V is a waste.

If you use it for stopping charging at the top end, base it on voltage not SoC.

And you still have the BP for the 12V bottom, which will usually be above 15%, well above any danger point - plus then the internal BB cutoff.
 

john61ct

Adventurer
Correct about the partial state of charge storage, somewhere between 40 and 60% is ideal.
actually storage is best at as low SoC as practical, not risking self-discharge too low, IMO at 12V is fine if cool conditions and checked monthly.
 

jonyjoe101

Adventurer
One thing I notice on lifepo4 is that the lower voltage you set your solar controller to the less amps it will get. So set to 14.6 volts is a good setting if you have no voltage drop between the controller and battery. After you have been using your lifepo4 for a while, if you think your solar isnt charging it at high enough amps, raise the bulk voltage. Unlike lead acid Lifepo4 will take every amp your solar panel can produce, up till the BMS shuts it off. Battleborn is a premium battery, I would use them for maximun performance.

I like fast charging my lifepo4 and I have a .5 voltage drop in the system. So I have my bulk much higher then 14.6 volts, the float is set to 14.5 volts to slow charge it to as close to 100 percent as possible. With the lifepo4 I been using it for the past year and don't worry too much whether I charge it to high or discharge it too much, it has perform extremely well, rarely get it below 70 percent. Only drained it once to were the BMS disconnected the power ,this occured after a week of cloudy weather where it wasn't getting fully charge every day. The resting battery voltage always reads 13.1 volts whether its 20 percent or 90 percent. Once the resting voltage goes below 12.9 volts you battery is almost dead.

If your battery monitor counts amps going in/out that will be the only way to track the batteries condition.

I recommend a disconnect relay like on my system, this will disconnect the solar panel when the battery reaches 14.4 volts. You never want the BMS to disconnect from the controller. When that happens (isolates) the controller will try to force the battery to take a charge, this creates voltage surges which will destroy anything connected to the battery. I lost about 4x 12 volt fans and many 12 volt lights from these surges, but havent since I added the relay. This can act as a deadman switch in case everything else fails, I wouldnt charge any lithium without one of these overvoltage relays. And the price is only 4 dollars for the relay itself, very cheap insurance.
diagram a.jpg
 

dreadlocks

Well-known member
I'll be going with a Victron SmartSolar 100V/50A MPPT controller and a Panasonic HIT 350W Solar Panel which runs at about 60v, at least thats the plan.. its bigger than what I need, but Ive been bitten before by wanting more solar yet doing so would exceed the capacity of the controller, better to have it and not need it than need it and not have it, what if I want to charge up a trolling motor too for a canoe? or some new fangled electric dirt bike, or what if I got my hands on a cheap golf cart for the kids to play with.. it is a toyhauler so its hard to predict what toys it may have over the next few decades or what power configurations I might want to setup to accommodate em.

The Victron unit can be programmed for whatever voltage outputs I desire, I could even limit current too.. I never had any issues frying things with my last solar setup (100W Solar, 100ah AGM, 140W Genasun MPPT Controller) and its weakness was no LVD, and if I didnt keep a good eye on it I was likely to over discharge it, I also didnt have a generator then so if I didnt have enough sun I was hooking the battery up to my tow vehicles alternator (installed a 75a powerpole on it) and idling the diesel all day.. found a photo of that, here's my previous portable solar generator:
IMAG0618.jpgIMAG0619.jpg
 
Last edited:
Top