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2oldman

NM

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Posted: 09/08/20 08:50am Link  |  Quote  |  Print  |  Notify Moderator

01tundra wrote:

h LiFePO4 batteries.....they don't all of a sudden die as you describe. They discharge and have a voltage vs SOC curve just like any other battery.
x2. This is how my Li pack behaves.

Itinerant1

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Posted: 09/08/20 10:02am Link  |  Quote  |  Print  |  Notify Moderator

Some of the replies in this thread just like other lithium battery threads are from folks that haven't used LFP but have tons of experience from reading but no hands on. [emoticon]

But they have phones, flashlights, tools that have a "lithium " chemistry so it must be the same.
__________________
12v 500ah (5,120Wh usable) , 20 cells_ 4s5p (GBS LFMP battery system). 8 CTI 160 watt panels (1,280 watts) 2s4p. Panels mounted flat on the roof. Magnum PT100 controller, Magnum 3012 hybrid inverter, ME-ARC 50. Installed 4/2016 been on 24/7/365


12v 500ah (5,120Wh usable), 20 cells_ 4s5p (GBS LFMP battery system). 8 CTI 160 watt panels (1,280 watts)2s4p,Panels mounted flat. Magnum PT100 SCC, Magnum 3012 hybrid inverter, ME-ARC 50. Installed 4/2016 been on 24/7/365, daily 35-45% DOD 1,600+ cycles.

01tundra

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Posted: 09/08/20 10:54am Link  |  Quote  |  Print  |  Notify Moderator

Itinerant1 wrote:

Some of the replies in this thread just like other lithium battery threads are from folks that haven't used LFP but have tons of experience from reading but no hands on. [emoticon]

But they have phones, flashlights, tools that have a "lithium " chemistry so it must be the same.
__________________
12v 500ah (5,120Wh usable) , 20 cells_ 4s5p (GBS LFMP battery system). 8 CTI 160 watt panels (1,280 watts) 2s4p. Panels mounted flat on the roof. Magnum PT100 controller, Magnum 3012 hybrid inverter, ME-ARC 50. Installed 4/2016 been on 24/7/365


Yep, there's misinformation all over the forums from people who have no direct knowledge of what they are stating assumptions about.....


2020 Rockwood Mini Lite 2109S
2017 GMC 2500HD Denali Duramax

2oldman

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Posted: 09/08/20 10:58am Link  |  Quote  |  Print  |  Notify Moderator

01tundra wrote:

Yep, there's misinformation all over the forums from people who have no direct knowledge of what they are stating assumptions about.....
I too was under the impression Li's kept voltage steady when I bought mine. I thought that was pretty cool.. but didn't really matter as I have a monitor.

* This post was edited 09/08/20 11:14am by 2oldman *

pnichols

The Other California

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Posted: 09/08/20 01:10pm Link  |  Quote  |  Print  |  Notify Moderator

01tundra wrote:

pnichols wrote:

pianotuna wrote:

msmith1199 wrote:



What is the advantage to them over Lithium? Is it just cost? Do they provide as much power?


As far as power goes 100 amp-hours is 100 amp-hours. However SiO2 may do larger discharge rates than LI. LI appear to be limited to about 1 C.

Similar to LI in that partial charging is just fine--though best practise is to do a full charge on a monthly basis.

advantages
1. can be used and charged at -40
2. can be run stone bone dead 620 times
3. can do 50% discharge 2800 times
4. no need to stop charging at 90% which LI prefer (for storage)
5. can do 80% discharge 1500 times

disadvantages:
1. heavier and larger foot print than Li
2. charge rate 4/c however if one has 300 amp-hours that hardly matters as convert size may not be able to get to 75 amps--without upgrading.


In addition to the silicon dioxide battery characteristics that Don lists above, they have one more advantage over lithium batteries that is important to me:

Lithium RV batteries hold their output voltage "high" right to the end before recharging ... their output voltage does not taper off a bit as they discharge .... unlike what the output voltage of lead acid batteries and that of silicon dioxide batteries does. To me the output not tapering off - like lithiums do - as they discharge IS NOT preferred ... it's a "disadvantage". It's nice to know when you're getting near the point where recharging is necessary by merely periodically checking the voltage on your RV's battery powered circuit - when that voltage reads around 12 volts, recharge them. As I understand it, silicon dioxide RV batteries act about the same way ... making it very simple to know about when to recharge them.

To get around this when switching to lithium RV batteries - in addition to their higher cost - you must spend even more money on what is technically known as an "integrating ammeter". This is a battery monitor that tracks how many amps are removed from the battery bank over time - thus showing how many amp hours have been used out of the battery bank.

To me, the above is just another gadget to buy in addition to the high lithium battery initial cost. Why have to purchase an amp hour consumption monitor - when silicon dioxide RV batteries have just about the same performance characteristics (they weigh more than lithium, but they recharge and operate at lower temperatures than lithium) as lithium RV batteries.

P.S. For example, I have a lot of lithium battery powered flashlights, remotes, and small tools ... AND IT'S VERY IRRITATING when they surprise you by suddenly dying with very little get-dim/slow-down type discharged warnings.


Having a battery monitor "gadget" is an accurate way to monitor the SOC of any type of battery chemistry, including lead acid.

Measuring with a volt meter is often misleading and very inaccurate, unless you let the battery sit for a hours at rest. But if you're really stuck on using this inaccurate method, the same can be done with LiFePO4 batteries.....they don't all of the sudden die as you describe. They discharge and have a voltage vs SOC curve just like any other battery.

LiFePO4 batteries are a complete different chemistry from Li batteries in flashlights and such.

How much personal experience do you have with LiFePO4 batteries in an RV?


An integrating ammeter type battery monitor for an LiFePO4 based RV system can be an expensive kindof toy, like so many things that we think we need nowadays. These type ammeters need to be calibrated relative to the actual battery(ies) that you're expecting it to monitor SOC accurately, and they should be recalibrated every once in a while to maintain their SOC accuracy as the capacity of the battery bank declines over time.

Lithium iron phosphate based RV/vehicle batteries are advertised to taper their output voltage less obviously than lead acid batteries -> and my lithium ion based small household batteries act that same way relative to the small amount that their output voltage tapers as they discharge and die on me. I know because I measure my lithium ion AA/AAA batteries with a four-place voltmeter. If one believes the performance curves published for LiFePO4 RV batteries, then my point was that this can be a very irritating characteristic because to know SOC one should add a special monitor to one's RV equipment in order to use LiFePO4 batteries in it. To me, it's just another thing to buy, install, and mess with.

Regarding my "zero experience" with LiFePO4 RV batteries ... experience is not the only way for one to know all they need to about something. Sometimes all the necessary knowledge can be gained a lot less expensively through what others report on regarding their experimentation and experience.

If my current bank of deep cycle Group 31 AGM RV batteries dies before I do, I'll seriously consider several factors before jumping on the hottest RV battery bandwagon. My rig currently has gobs of excess CCCC - so at this point in time based on published specifications only - the new silicon dioxide batteries in drop-in RV sizes read like they have real promise.


Phil, 2005 E450 Itasca Spirit 24V

2oldman

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Posted: 09/08/20 01:26pm Link  |  Quote  |  Print  |  Notify Moderator

pnichols wrote:

An integrating ammeter type battery monitor for an LiFePO4 based RV system can be an expensive kindof toy,
I like toys, especially the smart phone bluetooth kind.

01tundra

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Posted: 09/08/20 01:52pm Link  |  Quote  |  Print  |  Notify Moderator

pnichols wrote:

01tundra wrote:

pnichols wrote:

pianotuna wrote:

msmith1199 wrote:



What is the advantage to them over Lithium? Is it just cost? Do they provide as much power?


As far as power goes 100 amp-hours is 100 amp-hours. However SiO2 may do larger discharge rates than LI. LI appear to be limited to about 1 C.

Similar to LI in that partial charging is just fine--though best practise is to do a full charge on a monthly basis.

advantages
1. can be used and charged at -40
2. can be run stone bone dead 620 times
3. can do 50% discharge 2800 times
4. no need to stop charging at 90% which LI prefer (for storage)
5. can do 80% discharge 1500 times

disadvantages:
1. heavier and larger foot print than Li
2. charge rate 4/c however if one has 300 amp-hours that hardly matters as convert size may not be able to get to 75 amps--without upgrading.


In addition to the silicon dioxide battery characteristics that Don lists above, they have one more advantage over lithium batteries that is important to me:

Lithium RV batteries hold their output voltage "high" right to the end before recharging ... their output voltage does not taper off a bit as they discharge .... unlike what the output voltage of lead acid batteries and that of silicon dioxide batteries does. To me the output not tapering off - like lithiums do - as they discharge IS NOT preferred ... it's a "disadvantage". It's nice to know when you're getting near the point where recharging is necessary by merely periodically checking the voltage on your RV's battery powered circuit - when that voltage reads around 12 volts, recharge them. As I understand it, silicon dioxide RV batteries act about the same way ... making it very simple to know about when to recharge them.

To get around this when switching to lithium RV batteries - in addition to their higher cost - you must spend even more money on what is technically known as an "integrating ammeter". This is a battery monitor that tracks how many amps are removed from the battery bank over time - thus showing how many amp hours have been used out of the battery bank.

To me, the above is just another gadget to buy in addition to the high lithium battery initial cost. Why have to purchase an amp hour consumption monitor - when silicon dioxide RV batteries have just about the same performance characteristics (they weigh more than lithium, but they recharge and operate at lower temperatures than lithium) as lithium RV batteries.

P.S. For example, I have a lot of lithium battery powered flashlights, remotes, and small tools ... AND IT'S VERY IRRITATING when they surprise you by suddenly dying with very little get-dim/slow-down type discharged warnings.


Having a battery monitor "gadget" is an accurate way to monitor the SOC of any type of battery chemistry, including lead acid.

Measuring with a volt meter is often misleading and very inaccurate, unless you let the battery sit for a hours at rest. But if you're really stuck on using this inaccurate method, the same can be done with LiFePO4 batteries.....they don't all of the sudden die as you describe. They discharge and have a voltage vs SOC curve just like any other battery.

LiFePO4 batteries are a complete different chemistry from Li batteries in flashlights and such.

How much personal experience do you have with LiFePO4 batteries in an RV?


An integrating ammeter type battery monitor for an LiFePO4 based RV system can be an expensive kindof toy, like so many things that we think we need nowadays. These type ammeters need to be calibrated relative to the actual battery(ies) that you're expecting it to monitor SOC accurately, and they should be recalibrated every once in a while to maintain their SOC accuracy as the capacity of the battery bank declines over time.

Lithium iron phosphate based RV/vehicle batteries are advertised to taper their output voltage less obviously than lead acid batteries -> and my lithium ion based small household batteries act that same way relative to the small amount that their output voltage tapers as they discharge and die on me. I know because I measure my lithium ion AA/AAA batteries with a four-place voltmeter. If one believes the performance curves published for LiFePO4 RV batteries, then my point was that this can be a very irritating characteristic because to know SOC one should add a special monitor to one's RV equipment in order to use LiFePO4 batteries in it. To me, it's just another thing to buy, install, and mess with.

Regarding my "zero experience" with LiFePO4 RV batteries ... experience is not the only way for one to know all they need to about something. Sometimes all the necessary knowledge can be gained a lot less expensively through what others report on regarding their experimentation and experience.

If my current bank of deep cycle Group 31 AGM RV batteries dies before I do, I'll seriously consider several factors before jumping on the hottest RV battery bandwagon. My rig currently has gobs of excess CCCC - so at this point in time based on published specifications only - the new silicon dioxide batteries in drop-in RV sizes read like they have real promise.


Our LiFePO4 batteries start at 13.4V @ 100% SOC and are at 12.9V @ 20% SOC (maximum safe discharge floor) under no load. Lead acid is 12.6V @ 100% SOC and 12.2V @ 50% SOC (maximum safe discharge floor)under no load.

That's a 0.50V spread for LiFePO4 and 0.40V spread for lead acid.

You don't have to have a battery monitor for either chemistry, but if you dry camp a lot and like to really know where your SOC is then you should have one. A Victron BMV-712 monitors either chemistry.

Same goes for zero calibration, no difference in requirements.

I've had both and I'm stating facts that I've personally measured.

I have no hands-on experience with silicon dioxide batteries, so I can't speak to those.

For me, the weight savings, quickness of recharging, usable depth of discharge, warranty and customer service provided are all well worth the investment.

[image]

pianotuna

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Posted: 09/08/20 06:56pm Link  |  Quote  |  Print  |  Notify Moderator

01tundra and Itinerant1,

I'm not anti LiFePo4. They are excellent but costly.

But I need something that can survive -40. Only one chemistry for Li does that.

I'm 72--and SiO2 will outlast my ability to drive my class C.


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, soon to have SiO2 batteries, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

3 tons

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Posted: 09/08/20 09:45pm Link  |  Quote  |  Print  |  Notify Moderator

No doubt ‘Battery Wars’ are likely to continue, but in the end it’s the wants and needs of the ‘End User’ that drives innovation and ultimately marketplace offerings - from this perspective, the more choices the better off we are - it’s in this way that everybody wins!!

3 tons

pianotuna

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Posted: 09/08/20 11:52pm Link  |  Quote  |  Print  |  Notify Moderator

3 tons in s few short years there may be solid state batteries.

I agree with your sentiments!

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