Converting to LiFePO4 / Solar

[69hondo]

for sure!

and yes, this is definitely a labor of love! I got burned out on all the prep this time around (my fault... started late). Seems like I'm in too deep, and maintaining all this stuff is a part time job. I usually enjoy it when I have free time, but the problem is that I have no free time lol. That's why I kick around the idea of a cabover camper setup, a flatbed and sickkkkk buggy lol. Just blast out there, shred the dunes for 2-3 days and come back home. Gets me my fix. Then on the flipside, I love doing this as a family, and I don't think they'd really get a kick out of staying in a truck bed sized RV for 3-4 days lol

I totally get it. My kids love it. I think the wife just goes because we like it so much. LOL
But yeah where does it stop.

 

[mesquito_creek]

I guess we should all thank you personally for buying all the batteries and wrapping up your project… just in time for the black Monday sale on all these LiTimes. Normally I have to buy things for the price to drop for everyone else! Lol

 

[EmpirE231]

I guess we should all thank you personally for buying all the batteries and wrapping up your project… just in time for the black Monday sale on all these LiTimes. Normally I have to buy things for the price to drop for everyone else! Lol

The batteries are on sale right now for $620 each. I got them on Prime days deals or whatever for $637 each... so not too shabby... but if they dip even more, I might buy one more.

Panels are currently $184 each, I got them for $185 each. Unless they get some steep discounts, the prime day deals were pretty similar thankfully

 

[mesquito_creek]

The batteries are on sale right now for $620 each. I got them on Prime days deals or whatever for $637 each... so not too shabby... but if they dip even more, I might buy one more.

Panels are currently $184 each, I got them for $185 each. Unless they get some steep discounts, the prime day deals were pretty similar thankfully

Cool! You didn’t do bad… litime has a few other 12v form factors that are heavily discounted, but your set up isn’t ideal for those. The 12v 100ah mini size is crazy good at 269. I am gonna try out some of those for my “expedition” (lol) or better said: my glorified camping truck.

 

[mesquito_creek]

Your weakness at this point probably isn’t battery capacity, it’s the ability to charge them. You solar panels are doing about 750 watts because the winter sun angle is low with your panels mounted flat. The irony of a winter activity like glamis and solar.

Next time you are running the genny and charging off of that, post up the shunt app page that shows how many watts are actually going back into the battery through the shunt. My guess is there is some faster and better chargers to limit genny run time and speed up the charging.

But remember, takes about the same time to charge from 10% to 80% as it does to go from 80 to 100 because of the whole lifepo4 resistance dealio…. So if you can learn to modify your behavior and mind set by working the 10 to 80 range you might be good to go!

 

[EmpirE231]

Cool! You didn’t do bad… litime has a few other 12v form factors that are heavily discounted, but your set up isn’t ideal for those. The 12v 100ah mini size is crazy good at 269. I am gonna try out some of those for my “expedition” (lol) or better said: my glorified camping truck.

yeah those minis seem cool for small spaces. That battery / solar kid online tore one down recently and said they look good... they use pouch cells, but do not have the low temp cutoff.

Your weakness at this point probably isn’t battery capacity, it’s the ability to charge them. You solar panels are doing about 750 watts because the winter sun angle is low with your panels mounted flat. The irony of a winter activity like glamis and solar.

Next time you are running the genny and charging off of that, post up the shunt app page that shows how many watts are actually going back into the battery through the shunt. My guess is there is some faster and better chargers to limit genny run time and speed up the charging.

But remember, takes about the same time to charge from 10% to 80% as it does to go from 80 to 100 because of the whole lifepo4 resistance dealio…. So if you can learn to modify your behavior and mind set by working the 10 to 80 range you might be good to go!

yeah my solar guy said 75ish % rule of thumb for solar production, so I was hoping my 1200W of solar would get me closer to 900W of production.... but what you said about the winter sun makes sense. At my house where it was parked I was only seeing 400-500w which was sort of freaking me out lol.

My 2 magnum inverters are capable of charging @ 100 amps each. The problem I'm running into with that is that it gets the batteries to 80-85% and really slows down how many amps it's pumping into them. I will get some shunt info when they are charging at full power. I was also surprised to see how often my fridge is cycling...and how many amps the inverters just being in standby mode draws.

I am seeing about 3 amps of juice just by having inverter #2 (house) on, with no loads running.

so for inverter #1 (fridge only) I am seeing about 4 amps when the fridge is not cycling... and anywhere from 8-10amps of draw when it is cycling

 

[mesquito_creek]

yeah those minis seem cool for small spaces. That battery / solar kid online tore one down recently and said they look good... they use pouch cells, but do not have the low temp cutoff.

yeah my solar guy said 75ish % rule of thumb for solar production, so I was hoping my 1200W of solar would get me closer to 900W of production.... but what you said about the winter sun makes sense. At my house where it was parked I was only seeing 400-500w which was sort of freaking me out lol.

My 2 magnum inverters are capable of charging @ 100 amps each. The problem I'm running into with that is that it gets the batteries to 80-85% and really slows down how many amps it's pumping into them. I will get some shunt info when they are charging at full power. I was also surprised to see how often my fridge is cycling...and how many amps the inverters just being in standby mode draws.

I am seeing about 3 amps of juice just by having inverter #2 (house) on, with no loads running.

so for inverter #1 (fridge only) I am seeing about 4 amps when the fridge is not cycling... and anywhere from 8-10amps of draw when it is cycling

Well congrats, once you start making your own electricity it like crack cocaine, you just want to figure out how to make more. Take some time to really get a feel for what’s going on.

The magnum charging issue may be real in term of them having to slow down once the battery resistance goes up. That’s kinda the whole deal with mppt solar chargers kicking ass. I have 4k panels and 21kw batteries and I push 3600 watts all the way to the top 100%. I am totally off grid, no meter, no fuel. Once the sun goes down and batteries are dead I am burning candles.

Nice work!

 

[mesquito_creek]

You have a 12v system correct? So 3 amp idle consumption is 36 watts? … don’t sweat it, that’s not your issue, that’s actually pretty good.

 

[EmpirE231]

Well congrats, once you start making your own electricity it like crack cocaine, you just want to figure out how to make more. Take some time to really get a feel for what’s going on.

The magnum charging issue may be real in term of them having to slow down once the battery resistance goes up. That’s kinda the whole deal with mppt solar chargers kicking ass. I have 4k panels and 21kw batteries and I push 3600 watts all the way to the top 100%. I am totally off grid, no meter, no fuel. Once the sun goes down and batteries are dead I am burning candles.

Nice work!

Thanks man! Yeah I caught myself checking the shunt info and charger info a lot on the last trip, geeking out on it and trying to figure it all out haha.

Yes I’m a 12v system.

 

[SW_GLASS]

Awesome write up on your new solar and Lifepo4 battery setup. Thank you for posting this as it answered alot of my questions. I still have one question i am trying to answer before I upgrade my batteries like you did if you dont mind.

I am going back and forth on if I should use the LI-BIM 225 isolator or a DC - DC charger to protect my alternator when the coach is running. I was curious if you happened to look at your smart shunt while driving to see what the batteries were drawing while you were driving. I like the idea of using the isolator to control everything but I am afraid it will not limit the battery draw from the alternator and if the batteries are to almost dead when you start driving it eventually lead to alternator failure.

I appreciate any help you can offer with your recent use of your new system.

 

[EmpirE231]

Awesome write up on your new solar and Lifepo4 battery setup. Thank you for posting this as it answered alot of my questions. I still have one question i am trying to answer before I upgrade my batteries like you did if you dont mind.

I am going back and forth on if I should use the LI-BIM 225 isolator or a DC - DC charger to protect my alternator when the coach is running. I was curious if you happened to look at your smart shunt while driving to see what the batteries were drawing while you were driving. I like the idea of using the isolator to control everything but I am afraid it will not limit the battery draw from the alternator and if the batteries are to almost dead when you start driving it eventually lead to alternator failure.

I appreciate any help you can offer with your recent use of your new system.

So I did a little research on the LI-bim vs DC to DC, and to my understanding the initial design of the Li-bim is to save your alternator.

When running, I have checked the smart shunt and see the amps coming into my battery bank, around 90ish amps. And the. Also see that is does cycle off. Also when my batts reached 100% it completely stayed off. During this drive, it was just the fridge running and a couple other devices with both inverters on, meaning my draw was somewhere around 8-15amps at any given time. So most likely when the li bim is charging my batteries, it is pumping in a good 100 amps or so into my battery bank.

Not sure long term how this will affect the alt or if it’s perfectly fine. I do like the idea that it brings the batteries up quicker, as most of our drives are a shorter 3-4 hours to the desert. Nice to show up with 100% batteries.

This is way above my level of knowledge, but according to my solar guy, the li bim also works both ways to keep batteries balanced, as in if we’re plugged into shore power or genny is running continuously, it will help protect my chassis batteries from being cooked. Also plays a role in keeping my auxiliary start function available.

Definitely still in the learning phase with this system.

 

[Steve-o]

Like you EmpirE231 I don’t mind running my generator. I was thinking of doing the Lifpo4 but damn it’s overwhelming to figure out exactly what I need. I don’t want to do solar if I don’t have to. I had it on my trailer and found it rarely useful. I keep my Moho covered at home and usually camp at the beach with power. Desert is where I need the batteries to do their job. Do you think if we run the genie 3-4 hours a day in Glamis that we won’t need solar? Also, who did you use? I’m in SoCal and noticed Renogy is in Ontario.

 

[SW_GLASS]

So I did a little research on the LI-bim vs DC to DC, and to my understanding the initial design of the Li-bim is to save your alternator.

When running, I have checked the smart shunt and see the amps coming into my battery bank, around 90ish amps. And the. Also see that is does cycle off. Also when my batts reached 100% it completely stayed off. During this drive, it was just the fridge running and a couple other devices with both inverters on, meaning my draw was somewhere around 8-15amps at any given time. So most likely when the li bim is charging my batteries, it is pumping in a good 100 amps or so into my battery bank.

Not sure long term how this will affect the alt or if it’s perfectly fine. I do like the idea that it brings the batteries up quicker, as most of our drives are a shorter 3-4 hours to the desert. Nice to show up with 100% batteries.

This is way above my level of knowledge, but according to my solar guy, the li bim also works both ways to keep batteries balanced, as in if we’re plugged into shore power or genny is running continuously, it will help protect my chassis batteries from being cooked. Also plays a role in keeping my auxiliary start function available.

Definitely still in the learning phase with this system.

Thank you for the info I appreciate it. I think I am gonna go with the li-bim 225 as well just want to make sure it doesn't cook the alternator. Just wanted to make sure. Have a good one.

 

[EmpirE231]

Like you EmpirE231 I don’t mind running my generator. I was thinking of doing the Lifpo4 but damn it’s overwhelming to figure out exactly what I need. I don’t want to do solar if I don’t have to. I had it on my trailer and found it rarely useful. I keep my Moho covered at home and usually camp at the beach with power. Desert is where I need the batteries to do their job. Do you think if we run the genie 3-4 hours a day in Glamis that we won’t need solar? Also, who did you use? I’m in SoCal and noticed Renogy is in Ontario.

it is sort of overwhelming.... I needed new batteries, and am tired of messing with flooded or AGM every 3 years or so it seems, and really wanted to go lithium because it sounds like they "should" last a decade or longer. I think the solar isn't really necessary. It is nice, but not necessary. But I would definitely go the lithium route if needing to replace your batteries. Making sure everything is set up to charge correctly is the key. see next post for more details.

 

[EmpirE231]

Okay update as I continue to be in the learning process. Even though my remotes and inverters were both able to be set to the "custom" battery profile, and they were set w/ the correct parameters.... due to the versions of my hardware, it wasn't doing everything properly. (see post #56 about batteries only getting up to 80% charge from the inverters alone). So I called and spoke with magnum (super helpful BTW) ... they explained the remotes need to be version 2.8 or higher, and the inverters need to be 5.8 or higher. Well one of my inverters is very new and was a 6.0 so we're good there, but the other inverter is a 3.7 (built in 2011) also both my remotes were 2.6.

So I ended up ordering 1 new remote, to take advantage of the newer inverter. This allowed me to use battery type "LFP" on the setting rather than custom. And now when plugged in, or running the genny, my charger will function properly all the way to 100% instead of stopping at 80%. Also noticed it allows the pass through power to work more properly .

learning a lot as I go. Will most likely swap the older inverter and remote in the off season, so I can charge from both.... but for now this should work. Each inverter is capable of charging at 100 amps. One perk is I have the same inverter and remote in my trailer... so I will just swap those into my motorhome as they are both the newer versions.... and the trailer only has AGM's, so its not really needed there.

Now the next thing I need to figure out is absorption time.... all the reading online, some say no absorption time, some say yes. Magnum says to set it at 3 hours, based on my 690AH... and charging off 1 inverter. I sent in email to Li Time to see what they recommend.

 

[mesquito_creek]

Okay update as I continue to be in the learning process. Even though my remotes and inverters were both able to be set to the "custom" battery profile, and they were set w/ the correct parameters.... due to the versions of my hardware, it wasn't doing everything properly. (see post #56 about batteries only getting up to 80% charge from the inverters alone). So I called and spoke with magnum (super helpful BTW) ... they explained the remotes need to be version 2.8 or higher, and the inverters need to be 5.8 or higher. Well one of my inverters is very new and was a 6.0 so we're good there, but the other inverter is a 3.7 (built in 2011) also both my remotes were 2.6.

So I ended up ordering 1 new remote, to take advantage of the newer inverter. This allowed me to use battery type "LFP" on the setting rather than custom. And now when plugged in, or running the genny, my charger will function properly all the way to 100% instead of stopping at 80%. Also noticed it allows the pass through power to work more properly .

learning a lot as I go. Will most likely swap the older inverter and remote in the off season, so I can charge from both.... but for now this should work. Each inverter is capable of charging at 100 amps. One perk is I have the same inverter and remote in my trailer... so I will just swap those into my motorhome as they are both the newer versions.... and the trailer only has AGM's, so its not really needed there.

Now the next thing I need to figure out is absorption time.... all the reading online, some say no absorption time, some say yes. Magnum says to set it at 3 hours, based on my 690AH... and charging off 1 inverter. I sent in email to Li Time to see what they recommend.

I am pro “no absorption”, because it really doesn’t do anything, the bms manages cell balancing. But it doesn’t really hurt either…. You batteries are going to calendar age out regardless of any of the charging tweaks. You can’t cycle them 3000 - 5000 times unless you are living full time in your RV.

My guess is that magnum recommends it so that it allows the inverter to cool down after 100 amps continuous. But that’s just the conspiracy guy in me.

 

[EmpirE231]

I am pro “no absorption”, because it really doesn’t do anything, the bms manages cell balancing. But it doesn’t really hurt either…. You batteries are going to calendar age out regardless of any of the charging tweaks. You can’t cycle them 3000 - 5000 times unless you are living full time in your RV.

My guess is that magnum recommends it so that it allows the inverter to cool down after 100 amps continuous. But that’s just the conspiracy guy in me.

if it were to let the charger cool down, wouldn't it be better that they recommend no absorption? At that point it would go to float... which draws less amps.... or am I way off on this?

 

[mesquito_creek]

if it were to let the charger cool down, wouldn't it be better that they recommend no absorption? At that point it would go to float... which draws less amps.... or am I way off on this?

You are not way off…

During Absorption Charging, constant-voltage regulation is applied but the current is reduced as the solar batteries approach a full state of charge. This prevents heating and excessive battery gassing.

So I assume the magnum slows the charge down from 100amp to something lower and less heat…

But I don’t think it’s really a big deal either way. I use mppt chargers built to run full tilt. If magnum recommends an absorption charge go with it. It’s not going to alter the life of your battery since it’s not being throttled up and down every day for 365 days a year.

 

[mesquito_creek]

LiTime charging spec:

CHARGE
Charge Method：CC/CV
Charge Voltage：14.4V ± 0.2V
Recommend Charge Current：46A (0.2C)

CC/CV is constant current / constant voltage
No absorption no float…

 

[EmpirE231]

LiTime charging spec:

CHARGE
Charge Method：CC/CV
Charge Voltage：14.4V ± 0.2V
Recommend Charge Current：46A (0.2C)

CC/CV is constant current / constant voltage
No absorption no float…

so are you telling me I didn't need a new remote lol

according to that, should I be using the CC/CV profile on the magnum remote instead of the LFP?

talk about confusion lol.... we're all learning here, and I'm the guinea pig

 

[mesquito_creek]

I deleted that long rambling post.

If it’s getting you to 100% don’t sweat it. You are good. You needed the new remote.

It’s not really important whether to use absorbsion or float… the lifepo4 doesn’t give a shit! You will not hurt it! Whatever the magnum needs to get the job done.

If you change your charger or magnums in the future just don’t use absorb/float

 

[mesquito_creek]

So I am biting the bullet on my last conversion to LiTimes. I have a solar set up on my truck with a 7 year old x2power AGM. The agm capacity is down to the point that it can’t hold my 12v dometic fridge and run my coffee maker. It’s been a good battery but at $360 replacement cost I will be the Guinea Pig on one of the new LiTime minis. 40% more capacity and half the size and weight for $269 delivered to my front door.

 

[EmpirE231]

So I am biting the bullet on my last conversion to LiTimes. I have a solar set up on my truck with a 7 year old x2power AGM. The agm capacity is down to the point that it can’t hold my 12v dometic fridge and run my coffee maker. It’s been a good battery but at $360 replacement cost I will be the Guinea Pig on one of the new LiTime minis. 40% more capacity and half the size and weight for $269 delivered to my front door.

gotta report back on how it works out for ya. The youtube kid that tears them apart tore into one of the minis... said it uses pouched cells to be that much smaller (renogy uses pouch cells as well). Said the only downside was no low temp cutout.

 

[mesquito_creek]

Are you running your 12v devices directly off your LiTime batteries? On my destination RV I do not, I just plug the whole trailer into a shorepower outlet powered by large scale off grid 240v/50a inverter/battery/panels. So the 12v Rv devices are powered off of one 12v lead battery. That battery is maintained by the ac converter plugged into solar shore power.

The nominal voltage of lifepo4 is 13.5 vs 12.5 on lead. It normally isn’t an issue. Even 12v lead can have voltages up to 13.2 or slightly higher when fully charged. But lithium is higher under normal conditions.

I want to run a shurflo 12v Rv water pump directly off the LiTime mini. I can’t find anything in the manual about the operation range of the pump beside one line in trouble shooting about +- 10% (13.2). The LiTime will be about 13.5-13.8.

 

[mesquito_creek]

I called Pentair/Shurflo tech support and got the OK! They said the pumps are good up to 14v…

 

[EmpirE231]

Are you running your 12v devices directly off your LiTime batteries? On my destination RV I do not, I just plug the whole trailer into a shorepower outlet powered by large scale off grid 240v/50a inverter/battery/panels. So the 12v Rv devices are powered off of one 12v lead battery. That battery is maintained by the ac converter plugged into solar shore power.

The nominal voltage of lifepo4 is 13.5 vs 12.5 on lead. It normally isn’t an issue. Even 12v lead can have voltages up to 13.2 or slightly higher when fully charged. But lithium is higher under normal conditions.

I want to run a shurflo 12v Rv water pump directly off the LiTime mini. I can’t find anything in the manual about the operation range of the pump beside one line in trouble shooting about +- 10% (13.2). The LiTime will be about 13.5-13.8.

yep I am pretty sure all my basic 12V stuff in the motorhome just runs directly off the batteries.