RV.Net Open Roads Forum: Tech Issues: lithium question

RV Blog

  |  

RV Sales

  |  

Campgrounds

  |  

RV Parks

  |  

RV Club

  |  

RV Buyers Guide

  |  

Roadside Assistance

  |  

Extended Service Plan

  |  

RV Travel Assistance

  |  

RV Credit Card

  |  

RV Loans

Open Roads Forum Already a member? Login here.   If not, Register Today!  |  Help

Newest  |  Active  |  Popular  |  RVing FAQ Forum Rules  |  Forum Posting Help and Support  |  Contact  

Search:   Advanced Search

Search only in Tech Issues

Open Roads Forum  >  Tech Issues

 > lithium question

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 7  
Prev  |  Next
Sponsored By:
Reisender

NA

Senior Member

Joined: 12/09/2018

View Profile


Offline
Posted: 11/07/21 07:18pm Link  |  Quote  |  Print  |  Notify Moderator

StirCrazy wrote:

Reisender wrote:

StirCrazy wrote:

Reisender wrote:

StirCrazy wrote:

S Davis wrote:



EVE LifeP04 cells are 10% to 90% for 3500 cycles, they should still have 80% capacity at that point. If so these should outlast me.


I think your missreading that a bit.. the industry standard is that the cycles they list are based off a 100% usage. they recomend 10-90% use range and that will extend your cycle life possibly up to 5000-7000 cycles, before you reach that 80% threshhold. then that 80% could be maintained for another 10 years or longer, if you treat them good.

Steve



Yep. This is why Hertz rent a car is buying 100,000 base models of an EV that uses LFP batteries. An expected battery lifetime of a million kilometres vice other chemistries. You can pretty much run LFP to zero frequently without as much worry of damage. 10 to 90 is much better though. The sacrifice is they are heavier and performance suffers a bit from the higher end models.

We are kicking around the idea of putting something like a battle born in our new little trailer that comes with 2 x 6 volt AGM’s. The cheap skate in me says live with the AGM’s and wait a few more years and the price delta to come down. Guess we’ll see.


haha AGM, up here, are more expensive that some of the new LFP on the market. and if you can hook up a four 6V battery sety up in your camper you can build your own batter setup with prismatic LFP cells which is so much cheeper. Battle born is way over priced now, there competators in the market and I believe they all agreeded on a price trying to hold on to the prices they set when they were only one of 3 range.

Steve


Yep, they are pricey. But am I right? You seem to have a good handle on this. The trailer comes from the factory with 2 x 6!volt AGMs. Would an LFP 31 not be giving up a bit as far as useable amp hours? They are in a heated area so that’s not an issue.


you could be depends on the exact size of the 6V agms, but we can assume say 180ah??? then a 100 AH LFP would give you the same amount aproximatly of usable , but in a pinch with the 6V you could go down to 20% which means in a emergency you would hve a 144AH capacity. I dont like to size LFP to use the "equivalant" usable AH I like to take advantage of the size and weight and get more AH in a lighter and smaller package. so for me I would realy go with two of thoes batteries, run them nice and take that cycle life through the roof and when you need it you will have a total of 200AH for use in an emergency, but you'll probably never buy another set of batteries in your life.

Steve


Thanks Steve. That’s probably the way we’ll go. Although we’ll probably give it a go with the 2 AGM’s for the first season. This little trailer has hydronic heat and hot water so no big furnace fan load. I’m told by other T@B 400 owners that the 2 6 volts and solar panel are good for at least a few days of dry camping. But I know where we like to camp and quite often there is shade involved soooooo.... ,, the solar panel may be of limited use.

The reality is the tow vehicle is a Tesla with an 82 KWH battery so it will never be a crisis as we can just tap into that reserve via the 16 amp accessory port. We did some tests to insure this would work. But it’s extremely inefficient as it uses double conversion from DC to AC back to DC again. As well the car has to be “on” which wastes a couple watts right out of the gate.

A friend of ours bought a champion 2500 watt propane (dual fuel) super quiet genny from Costco. We are going to look at it and see if it would be handy for extended dry camping. We have a bigger champion for backup home power and are really happy with it but too big to drag with us. The little one is around 50 pounds so not bad. But we prefer not to have to drag a genny with us. Or at least not on a regular basis. But as you know, your and our area has a ton of great non serviced camp sites close to us. (We are in Vernon). It will probably be handy to have a little propane genny.

Cheers and thanks for the info.

StirCrazy

Kamloops, BC, Canada

Senior Member

Joined: 07/16/2003

View Profile



Posted: 11/08/21 07:10pm Link  |  Quote  |  Print  |  Notify Moderator

Reisender wrote:

StirCrazy wrote:

Reisender wrote:

StirCrazy wrote:

Reisender wrote:

StirCrazy wrote:

S Davis wrote:



EVE LifeP04 cells are 10% to 90% for 3500 cycles, they should still have 80% capacity at that point. If so these should outlast me.


I think your missreading that a bit.. the industry standard is that the cycles they list are based off a 100% usage. they recomend 10-90% use range and that will extend your cycle life possibly up to 5000-7000 cycles, before you reach that 80% threshhold. then that 80% could be maintained for another 10 years or longer, if you treat them good.

Steve



Yep. This is why Hertz rent a car is buying 100,000 base models of an EV that uses LFP batteries. An expected battery lifetime of a million kilometres vice other chemistries. You can pretty much run LFP to zero frequently without as much worry of damage. 10 to 90 is much better though. The sacrifice is they are heavier and performance suffers a bit from the higher end models.

We are kicking around the idea of putting something like a battle born in our new little trailer that comes with 2 x 6 volt AGM’s. The cheap skate in me says live with the AGM’s and wait a few more years and the price delta to come down. Guess we’ll see.


haha AGM, up here, are more expensive that some of the new LFP on the market. and if you can hook up a four 6V battery sety up in your camper you can build your own batter setup with prismatic LFP cells which is so much cheeper. Battle born is way over priced now, there competators in the market and I believe they all agreeded on a price trying to hold on to the prices they set when they were only one of 3 range.

Steve


Yep, they are pricey. But am I right? You seem to have a good handle on this. The trailer comes from the factory with 2 x 6!volt AGMs. Would an LFP 31 not be giving up a bit as far as useable amp hours? They are in a heated area so that’s not an issue.


you could be depends on the exact size of the 6V agms, but we can assume say 180ah??? then a 100 AH LFP would give you the same amount aproximatly of usable , but in a pinch with the 6V you could go down to 20% which means in a emergency you would hve a 144AH capacity. I dont like to size LFP to use the "equivalant" usable AH I like to take advantage of the size and weight and get more AH in a lighter and smaller package. so for me I would realy go with two of thoes batteries, run them nice and take that cycle life through the roof and when you need it you will have a total of 200AH for use in an emergency, but you'll probably never buy another set of batteries in your life.

Steve


Thanks Steve. That’s probably the way we’ll go. Although we’ll probably give it a go with the 2 AGM’s for the first season. This little trailer has hydronic heat and hot water so no big furnace fan load. I’m told by other T@B 400 owners that the 2 6 volts and solar panel are good for at least a few days of dry camping. But I know where we like to camp and quite often there is shade involved soooooo.... ,, the solar panel may be of limited use.

The reality is the tow vehicle is a Tesla with an 82 KWH battery so it will never be a crisis as we can just tap into that reserve via the 16 amp accessory port. We did some tests to insure this would work. But it’s extremely inefficient as it uses double conversion from DC to AC back to DC again. As well the car has to be “on” which wastes a couple watts right out of the gate.

A friend of ours bought a champion 2500 watt propane (dual fuel) super quiet genny from Costco. We are going to look at it and see if it would be handy for extended dry camping. We have a bigger champion for backup home power and are really happy with it but too big to drag with us. The little one is around 50 pounds so not bad. But we prefer not to have to drag a genny with us. Or at least not on a regular basis. But as you know, your and our area has a ton of great non serviced camp sites close to us. (We are in Vernon). It will probably be handy to have a little propane genny.

Cheers and thanks for the info.


I have two deep cycles in my Camper with one 24V, 325 watt solar panel, using the furnace I am go 3 to 4 days with no sun and forever if I get sun (I am in Kamloops) the reason I want to do LFP in the camper isnt for the normal camping , but rather so I could install a microwave or somthing like that and for camping in the winter where the furnace draw will be higher than say octoberish. also in the camoer weight and size are key issues and they would reduce both of thoes a lot. my 6V's work but you realy need 4 to be able to rent higher curents deicently. thats the set up I have in the 5th wheel, it is going LFP to reduce the weight by 246lbs in the front, get back a bunch of my storage space and take my usable AH from 235 to 600ah.

Steve


2014 F350 6.7 Platinum
2016 Cougar 330RBK
1991 Slumberqueen WS100

Ivylog

Blairsville, GA and WPB, FL.

Senior Member

Joined: 06/30/2004

View Profile


Offline
Posted: 11/09/21 05:46am Link  |  Quote  |  Print  |  Notify Moderator

Why would you replace 2 new AGM batteries (good for 5+ years) with overpriced Lithiums…in 5 years the prices will be even lower. Assuming the cells I bought finally arrive, building a LifePo4 battery for $1/AH makes them price comparative with AGMs but 3X the cycles.


This post is my opinion (free advice). It is not intended to influence anyone's judgment nor do I advocate anyone do what I propose.
Sold 04 Dynasty to our son after 14 great years.
Upgraded with a 08 HR Navigator 45’...


Reisender

NA

Senior Member

Joined: 12/09/2018

View Profile


Offline
Posted: 11/09/21 08:03am Link  |  Quote  |  Print  |  Notify Moderator

Ivylog wrote:

Why would you replace 2 new AGM batteries (good for 5+ years) with overpriced Lithiums…in 5 years the prices will be even lower. Assuming the cells I bought finally arrive, building a LifePo4 battery for $1/AH makes them price comparative with AGMs but 3X the cycles.


Yep. And that’s why We are going to live with the 6 volt AGM’s for awhile and see how it goes. I will jump through a few hoops to make it work if I can, but camping under trees kinda takes the solar solution off the table. We usually move every few days but we don’t go usually very far before we are in our next camping and hiking spot so on the road charging may not be very effective. So if it doesn’t work with the 2 X 6 volt AGM’s it’s either a little portable propane inverter generator or upgrade to a couple of 31 LFP’s. The trailer (and SUV) don’t arrive until early 2022 so until then it’s kinda watch and learn what others are doing.

Cheers.

BFL13

Victoria, BC

Senior Member

Joined: 02/15/2006

View Profile



Posted: 11/09/21 04:34pm Link  |  Quote  |  Print  |  Notify Moderator

You can keep your FLA bank for normal RV work (furnace etc) and also get an LFP for the microwave, kettle, toaster, and TV work.

That way you don't need two LFPs to get enough AH for furnace plus MW, etc. The one LFP can run the MW etc, leaving enough AH on the existing FLA bank for furnace etc.

No wiring changes or converter changes.

The LFP goes anywhere you can stash it inside where it is warm along with its own inverter (needs some air for location) On arrival camping, run an extension cord from the LFP's inverter to outside where you can plug in the shore power cord to the extension cord.

You recharge the FLA bank same as now. You need a portable charger to top up the LFP as required. Or use your converter with jumper cables over to the LFP. put them away after.

I have this sort of set up in the MH for the winter camping off grid. The existing MH set- up is the same as in the Profile, but have moved the two SiO2s (you would use one LFP) from the TC to inside the MH (on the floor behind a chair) with its own inverter connected to that bank.

I run the TV/DVD off that bank to keep those AH off the 6s, which gives them more furnace time. The MW etc can be run off the inverter on the 6s as usual, but I could plug all that into the other inverter.

In your cases, you would do it with the MW's inverter on the LFP and camp as usual off the FLAs for the other loads.

Big lesson I learned with the TC and one 100AH SiO2 (would be the same with one 100AH LFP) is it can run the MW just fine with the high amps, but you still need AH for furnace etc. which means you need 200AH.

The idea here is to save money by keeping your existing FLA bank to do the furnace etc, and now you can do the MW etc with just one LFP. You don't run the big stuff very long, so you don't need a ton of AH--just the high amp discharge the LFP can provide.

Note in this scenario the converter is not on the same bank as the inverter so no loop issues plugging into the shore power cable.


1. 1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
Photo in Profile
2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
See Profile for Electronic set-ups for 1. and 2.

pianotuna

Regina, SK, Canada

Senior Member

Joined: 12/18/2004

View Profile


Offline
Posted: 11/09/21 06:09pm Link  |  Quote  |  Print  |  Notify Moderator

BFL13,

Given that SiO2 can do 4C continuously, and can be taken to 0% state of charge, why would you suggest that it takes 2 SiO2 to equal 1 LiFePo4?


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

BFL13

Victoria, BC

Senior Member

Joined: 02/15/2006

View Profile



Posted: 11/09/21 06:42pm Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

BFL13,

Given that SiO2 can do 4C continuously, and can be taken to 0% state of charge, why would you suggest that it takes 2 SiO2 to equal 1 LiFePo4?


Didn't mean to say that, if I did. You can use the one LFP or SiO2 with its own inverter to run the MW etc, and use the existing FLA bank for the rest.

100AH is just not enough of any kind of battery bank for a weekend off-grid in the winter. If you don't have the FLA bank you need two LFPs (no mixing--second must also be LFP) or two SiO2s ( might get away with mixing types with them, but not for me thanks) to run it all.

Two FLAs can't run the MW like one of those others can with its high discharge rating, and you still need lots of AH for normal furnace running etc, so that means two of the expensive ones to get just 200AH.

Weight is an issue for these guys with small RVs or they could just have four 6s. That means LFP for the single MW one.

pianotuna

Regina, SK, Canada

Senior Member

Joined: 12/18/2004

View Profile


Offline
Posted: 11/09/21 09:17pm Link  |  Quote  |  Print  |  Notify Moderator

BFL13,

Thanks.

Reisender

NA

Senior Member

Joined: 12/09/2018

View Profile


Offline
Posted: 11/10/21 06:00am Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

pianotuna wrote:

BFL13,

Given that SiO2 can do 4C continuously, and can be taken to 0% state of charge, why would you suggest that it takes 2 SiO2 to equal 1 LiFePo4?


Didn't mean to say that, if I did. You can use the one LFP or SiO2 with its own inverter to run the MW etc, and use the existing FLA bank for the rest.

100AH is just not enough of any kind of battery bank for a weekend off-grid in the winter. If you don't have the FLA bank you need two LFPs (no mixing--second must also be LFP) or two SiO2s ( might get away with mixing types with them, but not for me thanks) to run it all.

Two FLAs can't run the MW like one of those others can with its high discharge rating, and you still need lots of AH for normal furnace running etc, so that means two of the expensive ones to get just 200AH.

Weight is an issue for these guys with small RVs or they could just have four 6s. That means LFP for the single MW one.


Yep. Weight is definitely an issue for us. But for two reasons. The batteries are located under the bed and slightly behind the axle. The hitch actually gets lighter as you add batteries. Not on a one to one ratio, but it does get lighter. I like to keep the trailer hitch weight at around 10 percent or more on any trailer I’m towing. Nice thing about little trailers is you can literally use a “large person” bathroom scale to accurately measure it. [emoticon]. Anyway. Adding another set of 6 volt AGM’s wouldn’t be an option for us. If we need more capacity it’s either

1. More solar (but we like to park in the shade so......)
2. A small propane generator to charge the 6 volts once per day for 45 minutes (prefer not doing this but maybe).
3. Switching to a set of LFP 100’s Pricey but doable and the cabinet is ready for them.

Once we start camping in the spring we’ll figure it out. Can’t wait.

BFL13

Victoria, BC

Senior Member

Joined: 02/15/2006

View Profile



Posted: 11/10/21 07:27am Link  |  Quote  |  Print  |  Notify Moderator

More idle thoughts:

You could stash the LFP and its inverter in the tow vehicle. Run the extension cord from it to the trailer shore power cord.

Note the 45 minutes won't put many AH back in even doing 50-80s.
Say you have a 60 amp charger and you are down 100AH /50%. 45 minutes will get you 45AH (minus a few for heat) so you are now at 145AH and you used 100 the first day, so by next day you are down another 100 to 45AH remaining.

Conserving to 50AH a day means you are down to 150/ 75% and where Bulk ends so your 60 amps will taper from the start doing the 75-90 so it will take longer. ( You don't do past 90 on generator on low amps and waste a lot of gen fuel for little return.) So you only are back to 180AH- restored 30AH of that 50. Next day you are down another 50 to 130AH and so on.

You could splurge the first day to get down to 50% and then do 50-90s. but in any case you will be running the gen for a couple hours a day or even longer depending, so you will need lots of propane or gasoline for it. Doesn't help if they are LFP--an AH is an AH no matter where it came from.

Having an EV for a TV you can plug into is very interesting--IMO that is the way to go if available. Nobody cares about efficiency while camping. You just want to get to tomorrow without freezing in the dark.

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 7  
Prev  |  Next

Open Roads Forum  >  Tech Issues

 > lithium question
Search:   Advanced Search

Search only in Tech Issues


New posts No new posts
Closed, new posts Closed, no new posts
Moved, new posts Moved, no new posts

Adjust text size:




© 2022 CWI, Inc. © 2022 Good Sam Enterprises, LLC. All Rights Reserved.