An ultimate lithium RV Battery?

[Phil G.]

Originally Posted by Elkman

Battle Born sells their LI-BIM devices for use to protect the batteries from charging damage to the lithium batteries. From their website:"The LiFePO4 Battery Isolation Manager (BIM) monitors voltage and connects batteries when needed. Under normal charging conditions, the BIM will connect for 15 minutes every 35 minutes. That means that the BIM will connect for 15 minutes, disconnect for 20 minutes, and repeat this cycle until the coach battery is charged.

If the coach battery resting voltage exceeds 13.4 V then the BIM will disconnect. A resting voltage greater than 13.4 V indicates a fully charged battery. Note that “resting voltage” means that no current is flowing to the coach battery.
The BIM will disconnect if the alternator voltage exceeds 14.4 V. This protects the coach battery from over charging. The LiFePO4 Battery Isolation Manager will disconnect if the voltage difference between the alternator and the coach battery is less than 0.1 V. If the voltage difference is too low, then there is a negligible charging current, and no need to connect to the coach battery. The BIM will disconnect if the alternator voltage drops below 13.3 V. If the alternator voltage is too low, then it cannot adequately charge the coach battery, so there is no reason to connect."

With the DC only fridge in my Navion lithium phosphate batteries are a must have if one wants to dry camp with the RV. The question is whether to get 100AH or 125AH and what connectivity is desired to the BIM. If my RV had a 3-way fridge I would have stayed with the factory flooded 105AH batteries but Winnebago stopped installing this type of fridge after 2019. If I had realized it was a DC only fridge I would not have bought the 2021 Navion.

You might want to consider a 200AH lithium battery, instead, that is close to the same size (Group 27-31) as many 12V 100/125AH lithium batteries. The idea being to have as much capacity as possible in any given size:
https://www.lithiumion-batteries.com...on-battery.php

[Winterbagoal]

Originally Posted by Phil G.

You might want to consider a 200AH lithium battery, instead, that is close to the same size (Group 27-31) as many 12V 100/125AH lithium batteries. The idea being to have as much capacity as possible in any given size:
https://www.lithiumion-batteries.com...on-battery.php

The 2021 Navion brochure states that the fridge is DC only. Page 4. No LP.

[Phil G.]

Originally Posted by Winterbagoal

The 2021 Navion brochure states that the fridge is DC only. Page 4. No LP.

A DC (12V) frigerator is exactly why I suggested a Group 31 200AH lithium battery instead of the more common Group 27/31 100AH lithium batteries. Maximum AH in the smallest volume should be the name of the game with any RV battery system - especially ones with refrigerators that are not LP.

[sajohnson]

OP: Thanks for the link to the batteries. They are impressive. Like others, I'm curious as to how the mfr is getting approx twice the amp-hours out of the same size case.

Regarding DC-DC chargers, something that hasn't been mentioned is that in addition to limiting charge current, they also provide the correct bulk/absorption/float voltages for LiFePO4 batteries.

The Sprinter chassis alternator only produces about 14.0V -- significantly less than the alternators in most vehicles, which are typically 14.4V.

As for the effect of high current, I have not been able to get a straight answer. Clearly, some older alternators can be destroyed under certain conditions, but newer alternators apparently have protection circuitry built-in.

So perhaps protected alternators that put out at least 14.4V can be connected directly, without a DC-DC charger. That's assuming the cables are large enough that there is minimal voltage drop, because most LiFePO4 battery mfrs specify a bulk/absorption voltage of 14.6V, and no less than 14.4V.

A continuous charge rate of up to 200A per battery, 400A per pair, will push any alternator -- even the highest output secondary/aux Sprinter alternators -- to their maximum regulated output. Here's a good thread for anyone interested:
https://sprinter-source.com/forums/i...threads/59632/

If an alternator is designed correctly that may be OK, but generally speaking alternators are not meant to run flat-out for long periods of time.

[Old Navy]

Originally Posted by sajohnson

OP: Like others, I'm curious as to how the mfr is getting approx twice the amp-hours out of the same size case.

Battle Born fits just over 100Ah in a Grp 27 case, and when Will Prowse did a tear down of that battery, there was a LOT of empty space under the cells. Still, it seems a stretch to fit 200Ah's in a group 31 case. Since the weight is about right for a 200Ah LiFePO4 , I'd guess the case might be a little over size. But I'd also be concerned that the company has no history I can find. I've never heard of them or seen their product offered for sale online or brick and mortar.

You can see the empty space when Will removes the cells at 5:10.

Battle Born Teardown

[jcurtisis]

Originally Posted by MicroMinnie

That's quite expensive or that capacity (imho) but guess their warranty is solid plus local.

But If you're technically inclined you can build 400AH very clean for << $2K ,
something that fits right in group31 x 2

Switching to lithium would also require a DC-DC charger in your case plus maybe some solar charges changes (if you have it)

Why does it “require” a DC-DC charger?

[al1florida]

Originally Posted by Phil G.

BINGO!! I agree 1000%.

The cutaway photos I've seen of drop-in 12V lithium RV capable batteries don't make me feel comfortable at all. A whole bunch of tiny cells matrix'd together with a cluster of PC boards and solder joints can be an open circuit failure waiting to happen from eventual corrosion and/or mechanical vibration.

I wish an "expert" lithium battery designer would jump onto some of these blog sites to explain why, say, a 100AH Group 27 size 12V lithium vehicle battery can't be made up of 3-4 large cells similar to the cell counts inside lead-acid batteries. Is it about the basic electro-chemistry involved that makes use of larger volume cell sizes impractical and/or unsafe ... or has it to do with it being cheaper to produce commom size vehicle drop-in batteries when using a bunch of small cells?

The small RV batteries (the size of golf cart batteries) are made up of small cells just like the large batteries that may contain hundreds or perhaps thousands of cells, like those that are used in electric power cars, such as Tesla.

It is not the number of cells that are grouped together, but how well they are built.

[BobC]

Personally, I wouldn't buy any LiFePO4 battery that hasn't passed a Will Prowse test and tear-down.

[AJMike]

Originally Posted by Phil G.

A DC (12V) frigerator is exactly why I suggested a Group 31 200AH lithium battery instead of the more common Group 27/31 100AH lithium batteries. Maximum AH in the smallest volume should be the name of the game with any RV battery system - especially ones with refrigerators that are not LP.

OK. So this is meant as a question, not as some authoritative comment.

You are suggesting that someone replace 2 Lithium batteries that are connected in parallel with one Lithium battery of the same capacity. If given that choice I personally would decline because I would be worried about losing a cell in one of the batteries. If that happens in a parallel setup you still have power because there are 2 batteries, but I assume if that happens with one battery you are just out of luck since you only have the one battery.

The question is whether or not my assumption is correct.

[Aerneau]

Looking at the pictures of the cell and construction of the cells I see a 100AH battery

[Old Navy]

Originally Posted by Aerneau

Looking at the pictures of the cell and construction of the cells I see a 100AH battery

The pictures are of 75Ah and 100Ah batteries they claim to sell. I have to wonder if this battery is vaporware at this point. As I said earlier, never heard of them and there is no info of them on the web. The web page is quite generic and filled with fluff and their address is a "shared office space" that people use to give the appearance of having an actual office when they don't. Lots of red flags here.

[AJMike]

Originally Posted by Old Navy

The pictures are of 75Ah and 100Ah batteries they claim to sell. I have to wonder if this battery is vaporware at this point. As I said earlier, never heard of them and there is no info of them on the web. The web page is quite generic and filled with fluff and their address is a "shared office space" that people use to give the appearance of having an actual office when they don't. Lots of red flags here.

I have generally found that it is better to do business with established companies when buying expensive technical equipment. Not necessarily large corporations, but places that have been in business for a while and have an association with places like the BBB.

I guess I also prefer places whose web pages contained text written in normal and proper English as it indicates familiarity with English speaking markets and some sophistication in marketing. And if the web page is going to mention that they employ many PhDs from major universities (they should learn to spell the plural of University) they should mention what those schools are. But perhaps that is just me.

[Phil G.]

Originally Posted by AJMike

OK. So this is meant as a question, not as some authoritative comment.

You are suggesting that someone replace 2 Lithium batteries that are connected in parallel with one Lithium battery of the same capacity. If given that choice I personally would decline because I would be worried about losing a cell in one of the batteries. If that happens in a parallel setup you still have power because there are 2 batteries, but I assume if that happens with one battery you are just out of luck since you only have the one battery.

The question is whether or not my assumption is correct.

What I'm suggesting is: In any given RV battery situation where one is considering use of 1 or 2-in-parallel Group 27/31 size 100AH 12V lithium batteries - why not use 1 or 2-in-parallel 200AH lithium batteries instead - for double the capacity in the same size storage space as would be required for lesser battery capacity from other manufacturers?

To me, battery energy per unit volume of battery size would seem especially important for RV'ers who want to use a compressor type refrigerator and often do camping without hookups in an RV with limited battery compartment space -> that is assuming they can budget for these Group 31 size 200AH 12V lithium batteries!

Here's more info on the company offering these Group 31 size 200AH lithium batteries: https://www.lithiumion-batteries.com/about-us.php

Note that: 1) They use stainless steel 5.5AH/each cells (does their competition use stainless steel or aluminum clad cells and of this capacity?), and 2) since their $$$$ price is up there for the Group 31 200AH batteries - in a competitive environment probably that means that you "have to be" getting what you pay for.

[misteracng]

Originally Posted by Old Navy

The pictures are of 75Ah and 100Ah batteries they claim to sell. I have to wonder if this battery is vaporware at this point. As I said earlier, never heard of them and there is no info of them on the web. The web page is quite generic and filled with fluff and their address is a "shared office space" that people use to give the appearance of having an actual office when they don't. Lots of red flags here.

This is one of the reasons I went with lithionics. Battleborn seems to be a good option as well for their support. Although there are definitely cheaper options, when there is a problem, thats when those savings may not be worth it.

[misteracng]

Originally Posted by Phil G.

What I'm suggesting is: In any given RV battery situation where one is considering use of 1 or 2-in-parallel Group 27/31 size 100AH 12V lithium batteries - why not use 1 or 2-in-parallel 200AH lithium batteries instead - for double the capacity in the same size storage space as would be required for lesser battery capacity from other manufacturers?

To me, battery energy per unit volume of battery size would seem especially important for RV'ers who want to use a compressor type refrigerator and often do camping without hookups in an RV with limited battery compartment space -> that is assuming they can budget for these Group 31 size 200AH 12V lithium batteries!

Here's more info on the company offering these Group 31 size 200AH lithium batteries: https://www.lithiumion-batteries.com/about-us.php

Note that: 1) They use stainless steel 5.5AH/each cells (does their competition use stainless steel or aluminum clad cells and of this capacity?), and 2) since their $$$$ price is up there for the Group 31 200AH batteries - in a competitive environment probably that means that you "have to be" getting what you pay for.

Getting 2 100AH lithiums is about double what I normally have with the flooded lead batteries. It would be nice to have potentially 400AH except cost. I was thinking that I might not actually need that much juice, but who knows. I hope the product is real. I just wonder why no one else is putting that much capacity in a group 31 battery. I'm sure there would be market for them. Also for my View, I kinda want to save 60lbs of weight, which helps with my low OCC.

[sajohnson]

Originally Posted by AJMike

I have generally found that it is better to do business with established companies when buying expensive technical equipment. Not necessarily large corporations, but places that have been in business for a while and have an association with places like the BBB.

I guess I also prefer places whose web pages contained text written in normal and proper English as it indicates familiarity with English speaking markets and some sophistication in marketing. And if the web page is going to mention that they employ many PhDs from major universities (they should learn to spell the plural of University) they should mention what those schools are. But perhaps that is just me.

It's just you -- you are far too skeptical!

Actually, I look for those things as well.

There are several errors in addition to the ones you pointed out. Also, on the "About Us" page, if you right click on any image and then click "Search Google for image" you will see that they are using 'stock' images. That alone is not a huge red flag, but something else to consider.

I also noticed that they list "Gov't Awards" and "Military Contracts" but they are not actually links -- just for show.

I've exchanged a couple emails with them -- I'll post separately about that.

[Old Navy]

After a little searching with whois, I found "smartbattery.com" shares the same IP address with this company, and some of the Chargex product pages still include "Smart Battery" branding and smartbattery.com labels and links. Looking at smartbattery.com's BBB page should give anyone considering a purchase some pause.

https://www.bbb.org/us/fl/fort-laude...864/complaints

It's possible this company has got it's act together. Rebranding and changing name, address and phone number can be to escape your reputation, and/or to try to rebuild from a failure. Or they could be under new ownership. With MY money, I wouldn't touch them with a 10 foot pole until they establish a reputation for providing a quality and standing behind their product.

[sajohnson]

Like almost all LiFePO4 battery mfrs/retailers, Chargex claims their batteries are, "Plug and play!" and "Drop-in replacements" for common lead-acid batteries.

While that may be true in some cases, in most installations modifications must be made and/or new equipment must be purchased. Needless to say, the mfr/reseller does not want to admit this because it will cut into sales.

Some things a person switching from lead-acid to lithium may have to deal with:

* Not all charging sources are fully compatible with LiPo batteries. Equipment that may have to be purchased includes one or more of the following:

> A "DC to DC charger" (more on that below).
> A new converter/charger
> A new solar charge controller
> A new inverter/charger

Most newer chargers will work with lithium batteries, and may even have a lithium (or "custom") setting, but some will need replacement.

* The terminals on LiPo batteries are *not* the same as those on GC2 batteries, which may require wiring changes.

* LiPo batteries have a limited charge and discharge temp range, so in some cases the factory battery box is not appropriate.

* They are often not a standard physical size, which may require different/altered hold-down hardware.

* The "battery level indicators" in most RVs will not work with LiPo batteries, because they are essentially voltmeters. LiPo batteries have very little voltage drop until they drop below about 10% SoC. That means if you want to have an idea of your lithium batteries' state of charge you will need a battery monitor (about $150>$200, plus installation if not DIY).

In the email exchange with Chargex, I did get the CSR to admit that we would need a DC-DC charger to use the alternator for charging. The Sprinter alternator puts out about 14.0V, which is already low (the CSR said that 14V would be good for an 85>90% SoC). Assuming the alternator has thermal protection, the primary problem is voltage drop. Under heavy load I've seen the chassis voltage drop to about 12.5V(!) and the input to the inverter (through two #4/0 welding cables) is about 12.0V.

It turns out that while Chargex claims "plug and play" they actually sell some DC-DC chargers -- so they are aware that their batteries are not always "drop-in replacements" after all.

The battery terminals are M8, which is essentially the same size as the 5/16" studs on GC2 batteries. That's better than the tiny M6 hardware Lion Energy uses (I have two Lion UT 1300 batteries that I'm considering returning to Costco). The problem with both mfrs' batteries is that instead of using a threaded stud that is firmly embedded in the case, they use a "button terminal" -- a threaded hole that accepts a M6 or M8 bolt. While that design works, there are at least 2 issues:

1) The entire assembly can break free (inside) and rotate. See Will Prowse's review of the Lion UT 1200. The UT 1300 was reinforced a bit but is not confidence inspiring. One battery with a better (but still not GC2 standard) design is the Battle Born.

2) With a stud, one can place as many terminals as will fit and still leave space for the nut and washer(s). With a bolt, one must select the proper length bolt which is determined by the number and thickness of terminals. Not a huge problem but one more thing to be concerned with if the supplied bolts are not the proper length.

The GC2 terminals are nice because they have both long 5/16" studs and the automotive standard tapered posts. I generally prefer the studs, but sometimes it is necessary and/or convenient to use the posts. Both are sturdy and I've never seen or heard of one breaking. I do not understand why people attempting to to sell LiPo batteries to RVers and boaters refuse to use the GC2 terminals that are so common.

Just a heads-up for anyone considering switching to LiFePO4 batteries.

[Old Navy]

Originally Posted by sajohnson

I also noticed that they list "Gov't Awards" and "Military Contracts" but they are not actually links -- just for show.

Government contracts are public information. Under what appears to be their previous name, "Smart Battery LLC", they did a total of $24,400 in contracts, the most recent being in 2013.

https://govtribe.com/vendors/smart-b...-battery-6a4t6

And yes, all the site pics are stock photos. The batteries are made in China. They even photoshopped their logo on some of the models.