Getting ready to turn the Express van into an adventure van. I'm diving into LiFePO4 learning and I like it. Since I'm not planning solar (I usually camp in the woods) I'm trying to figure out how to charge them.
From what I understand since they are slightly higher voltage with 4 in series, my van's charging system won't be adequate for topping them off and they're generally not compatible with the typical bulk/float charging that the alternator/regulator would provide.
Am I crazy for thinking there is some magic box that the alternator can give 125A @ 14.7v to and it makes a proper LiFePO4 charging flavor that the batteries will like?
I think you want a victron dc-dc charger because they like a steady voltage. I'm trying to figure this out for my old ass airstream also.
There are quite a few DC-DC systems out there designed for car voltage to LiFePO4 batteries. But the higher the power, the cost goes up a LOT. Also, your battery may limit how fast you can charge it- the one I have installed in my trailer can only be charged at 50A max.
Was a second alternator ever an option for that van/engine combo? In the vanlife world, that is a pretty common way to charge house batteries.
In reply to Curtis73 (Forum Supporter) :
Check out Will's channel for everything you ever wanted to know about LiFePO4.
https://youtube.com/c/WillProwse
Pete Gossett (Forum Supporter) said:
In reply to Curtis73 (Forum Supporter) :
Check out Will's channel for everything you ever wanted to know about LiFePO4.
https://youtube.com/c/WillProwse
And the forum that goes with it https://diysolarforum.com/
Ian F (Forum Supporter) said:
Was a second alternator ever an option for that van/engine combo? In the vanlife world, that is a pretty common way to charge house batteries.
There was an option, but I think it was only on the Duramax/cutaway van for things like Ambulances or Fire support vehicles.
Pete Gossett (Forum Supporter) said:
In reply to Curtis73 (Forum Supporter) :
Check out Will's channel for everything you ever wanted to know about LiFePO4.
https://youtube.com/c/WillProwse
Thanks for the rabbit hole :)
alfadriver said:
There are quite a few DC-DC systems out there designed for car voltage to LiFePO4 batteries. But the higher the power, the cost goes up a LOT. Also, your battery may limit how fast you can charge it- the one I have installed in my trailer can only be charged at 50A max.
That is a consideration. The DIY 280Ah setup I was thinking of can charge up to 125A but I think my alternator is only 120A. I think if I limit it to 80 or 100A I might have a happier alternator and it will still charge in a few hours.
Is there a cheaper source for prismatic batteries that I may be missing? Alibaba seems to be all over the board with questionable quality. I don't mind paying for good batteries, but I'm also a notorious cheapskate.
In reply to Curtis73 (Forum Supporter) :
The "best value" in van build batteries is a ... contentious... subject to say the least.
A large number of vanlife, F/T RVers and boat folks I follow have seemed to had good experience with Battleborn. Definitely not cheap, but so far none of the vendors are. All I know is for the build I want to do, I'm figuring about $10K for batteries, charge controller, misc hardware and so on. Probably more...
Some of the battery brands have built-in heaters to keep the batteries from being charged when cold, which may or may not be a concern.
Personally, I would not go with some sort of unknown off-brand. The amount of money you might save will not really be all that much and the quality control risk is high. In my experience, where a lot of the money is saved is in the QA/QC testing (or lack thereof). In this application, a faulty battery can literally burn your van to the ground.
Curtis73 (Forum Supporter) said:
alfadriver said:
There are quite a few DC-DC systems out there designed for car voltage to LiFePO4 batteries. But the higher the power, the cost goes up a LOT. Also, your battery may limit how fast you can charge it- the one I have installed in my trailer can only be charged at 50A max.
That is a consideration. The DIY 280Ah setup I was thinking of can charge up to 125A but I think my alternator is only 120A. I think if I limit it to 80 or 100A I might have a happier alternator and it will still charge in a few hours.
Is there a cheaper source for prismatic batteries that I may be missing? Alibaba seems to be all over the board with questionable quality. I don't mind paying for good batteries, but I'm also a notorious cheapskate.
The Will Power (from the link) regularly does reviews of batteries. Including tearing them down to look at each component. If you can deal with no cold charging protection, there are some pretty cheap options- to the point that it might be a decent deal to parallel 2x100ahr batteries together vs. making one.
Over time, my "plans" on fully electrifying my trailer has changed a lot- once I knew about how much the most power I used, I now know I can get a 48V battery that's similar to a server wrack one which will meet our power needs.
Which is to say- travel down that rabbit hole. You may find a great solution.
Ian F (Forum Supporter) said:
In reply to Curtis73 (Forum Supporter) :
The "best value" in van build batteries is a ... contentious... subject to say the least.
A large number of vanlife, F/T RVers and boat folks I follow have seemed to had good experience with Battleborn. Definitely not cheap, but so far none of the vendors are. All I know is for the build I want to do, I'm figuring about $10K for batteries, charge controller, misc hardware and so on. Probably more...
Some of the battery brands have built-in heaters to keep the batteries from being charged when cold, which may or may not be a concern.
Personally, I would not go with some sort of unknown off-brand. The amount of money you might save will not really be all that much and the quality control risk is high. In my experience, where a lot of the money is saved is in the QA/QC testing (or lack thereof). In this application, a faulty battery can literally burn your van to the ground.
I don't see needing anywhere near $10k worth of juice for the van. I think a pack of 4 EVE cells and a BMS and charger can get me 280Ah for under $1000. I'll be running a fan, and charging phones. I'm not even going to count the lights since they're about 2 watts. I could imagine having a heated blanket for colder nights which is 200w which could be run continuously for about 12 hours. The thought did cross my mind to have a 12v or 120v mini fridge, but I'm quickly changing my mind on that. If I can be convinced that a propane/evap fridge wouldn't asphyxiate me I might go that route.
In reply to alfadriver :
Most of the pre-assembled batteries that present a viable cost point don't have low temp charge protection. Seems like DIY-ing it with a proper BMS is the ticket there.
You're are plenty of people in Motorsports charging a lifepo4 battery using the stock alternator and no wiring changes.
This isn't lipo or li ion. It is much more robust and safer.
In reply to Curtis73 (Forum Supporter) :
Well, I did say, "for what I want to do" which is less "adventure" and more "be comfortable at night after a long, sweaty day during the Summer at a bike park." Meaning: I want A/C and don't I want to berk with a generator. That means having a fairly sizable battery bank, although there are now options that may reduce how big it needs to be. At this point, the largest load is likely to an induction cooktop.
I think your $1000 estimate is a bit optimistic, but I also accept you tend to be more willing to trade time for $ and I tend to do more of the opposite.
There are some very efficient 12V top-load fridge/freezers available, although they aren't cheap. However, such an option would eliminate the need for any sort of propane system and since "one fuel" is a concept I subscribe to, I have a strong desire to not add propane to my build. I'm willing to spend to make that happen.
But we've been having this debate for years... These sort of DIY builds are always a balance of priorities. What may be important to one builder may be of less importance to another. That doesn't make either POV wrong.
In reply to Curtis73 (Forum Supporter) :
But there are some low cost ones out there. Will finds them pretty often.
BTW, in terms of cells- the DIY solar group does get group buys. While I'm still not ready to get one, I did ask, and the cell price was really good- they really examine the good suppliers from Aliexpress.
BTW- pts 2- what are you running with the battery? For that kind of energy, it seems that you are planning on an inverter. And if that's the case, for the sake of the peak current capability- consider 24v, 36v, or even 48v. I want to run 3600W nominal (same as my current 30A input), so a 48V system means less than 100A nominal peak.
Ian F (Forum Supporter) said:
In reply to Curtis73 (Forum Supporter) :
Well, I did say, "for what I want to do" which is less "adventure" and more "be comfortable at night after a long, sweaty day during the Summer at a bike park." Meaning: I want A/C and don't I want to berk with a generator. That means having a fairly sizable battery bank, although there are now options that may reduce how big it needs to be. At this point, the largest load is likely to an induction cooktop.
I think your $1000 estimate is a bit optimistic, but I also accept you tend to be more willing to trade time for $ and I tend to do more of the opposite.
There are some very efficient 12V top-load fridge/freezers available, although they aren't cheap. However, such an option would eliminate the need for any sort of propane system and since "one fuel" is a concept I subscribe to, I have a strong desire to not add propane to my build. I'm willing to spend to make that happen.
But we've been having this debate for years... These sort of DIY builds are always a balance of priorities. What may be important to one builder may be of less importance to another. That doesn't make either POV wrong.
In terms of power hogs, A/C isn't nearly the problem as a heater is. We have a portable A/C unit (yea, the ones that are far from the most efficient, but it fits easily) that uses a LOT less energy than our electric space heater.
I plan on running basic stuff. I don't care about heat unless it's 100 degrees at night... at which point I need to re-assess my choices as an adult and not camp on those nights. So no A/C.
I'll be running a squirrel cage fan for cooling, charging phones and possibly a laptop, and about 2 watts worth of LED lighting occasionally. A typical evening for me camping I might watch a movie on the laptop or read a book, but for reading I use a clip light with its own battery. Cold nights I have two options; run a 500w space heater, or a 200w heated blanket. The space heater only runs maybe half the time depending on how cold it is, but I don't usually camp in frigid temps.
I will likely install an inverter, but truth is I probably don't need it. My original plan was to have a little 120v dorm fridge, but they are just wasteful in the energy game. I do need something self-cooling. I often disappear in the woods for a week at a time and ice is a pain in the butt.
The best value batteries is still lead acid really, Trojan makes a bunch of different options that are tried and true
Antihero (Forum Supporter) said:
The best value batteries is still lead acid really, Trojan makes a bunch of different options that are tried and true
Depends on how much space and weight capacity you have as well as how often you plan to use the system. Lead acid deep cycle batteries can take fewer discharge/recharge cycles than new types. I've seen a few life-of-use calcs where newer tech beats lead acid in cost over time because they don't have to be replaced as often.
I'm saying lead acid don't have their place - I spec them all the time for building UPS systems. But those are situations where the batteries might see a full discharge once or twice over the life of the system, so they are usually just sitting in the cabinet ready to go, rarely seeing a discharge at all other than some regular testing cycles or on the rare occurance the back up generator in the facility fails to start.
The ARB fridge freezers work well enough to keep popsicles frozen during summer in Moab and draw little enough power to run all day (plus) on the starting battery of a rock crawler without risking the ability to start. Sadly, their price reflects their quality (probably plus there, too.) I think they are about 1000 these days, but they just work so well... No, I don't have one, but I am jealous of the ones I have seen.
In reply to Curtis73 (Forum Supporter) :
There have been some really good videos out there comparing 120V compressor vs 12V compressor vs, any absorber fridge. I would very much suggest looking those up. But while the 120V dorm fridge might be wasteful- they are way better than an absorption fridge on electricity, and they are really not far off of the 12V compressor ones. And when you factor in cost, the dorm fridge w/ it's own inverter isn't that bad. Although, if you are ok with a cooler shape fridge, the 12V compressor ones can be found pretty inexpensive.
If you park where there is sun, anymore, you will not have any problems keeping a fridge running forever.
Anyway, the "problem" with where you are now is the massive amounts of choices. DIY, Server rack, cheap 100ahr, etc. Heck, if you never do anything under 40F, having cold temp charging protection isn't a big deal. Basically, you can do anything, and no matter what you choose, it will end up working great.
(WRT the lead-acid batteries- 200Ahr of lead acid is the same as 100Ahr of LiFePO4. And it weighs about 1/4 of the lead. The cost for the LiFePO4 is getting really close, too- especially if you factor in number of charging cycles)
One more thing- while i know you are a VERY (VERY) experienced RV'er, I'm not sure how up you are on doing it with as little as possible- which I thing this channel does well- https://www.youtube.com/c/CheapRVliving
And he's done some good 12V Fridge reviews. Like this one- a cooler layout fridge that is split into freezer and fridge- https://www.youtube.com/watch?v=ZJpLU6xqO7I&ab_channel=CheapRVliving
Parking in the sun is something I almost never do. I'm a deep woods kinda guy. I also don't want to occupy the entirety of my roof rack with panels because it will get used for lumber, sleeping out on nice nights, and used as an actual cargo rack. I also don't see the need for the additional cost and complexity when I can just charge it off the alternator on my way to the next site.
I did watch several videos on compressor vs absorption. There was one video where they tested about 6 different units and the clear winner was a 120v fridge on an inverter... provided you have an efficient inverter that doesn't draw a lot of its own juice.
As far as experience with minimalist camping, I have a fair amount of time spent in the boonies with nothing but a bivvy sack and a beer can/isopropyl stove, but these days I'm too old and creaky for that stuff. This van is my old-guy minimalist camping compromise. But yes, most of my RV time is in a nice 5er with A/C, microwave, and a 32' flat screen.
Even though I wouldn't be camping in really cold weather, I still use the van in cold weather. I suppose I could disconnect or remove the batteries in the winter, I'm just thinking if I go outside on a 15 degree morning and the batteries call for a charge it might do bad things.
