Good Sam Club Open Roads Forum: LiFePo4 vs Lead Acid...Some points of interest.
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

 > LiFePo4 vs Lead Acid...Some points of interest.

Reply to Topic  |  Subscribe  |  Print Page  |  Post New Topic  | 
Page of 19  
Prev  |  Next
Freep

Wisconsin

Senior Member

Joined: 04/14/2017

View Profile


Offline
Posted: 04/14/21 12:12pm Link  |  Quote  |  Print  |  Notify Moderator

So 3 Ton, what makes you think the Victron Smart Shunt is doing anything different than the other two meters?


Quote:

If I accept (say for argument...) your idea that 20% is the cut-off point, then as was pointed out in both of the FLP discussions I pointed to, it’s the region below 50% SOC where coulomb counting alone begins to fall short (thus, 50-20’ish %) and where accuracy becomes a more driving concern...I take note of your position that this has only a negligible effect...


I don't think you'd be able to tell a difference between 50 and 20 because of the flat discharge curve of LiFePo4 cells. Counting amps is going to be just as accurate as counting amps and taking voltage into account.

I think this is especially true in our RV application. The video you referenced was talking about EVs. That's a much different use case. In an EV application you're going to see drift by counting amps because of the high current and high amperage conditions that we just don't see in RV house battery applications.

It would be interesting to run some experiments on these meters to verify. I'm pretty sure Will Prouse has already done that, I'll have to check.

Here's a picture of the discharge curve at 2C for my battery. Keep in mind that discharging at 2C is not normal and the discharge rate would be much lower and therefor the curve would be even flatter until it falls off. Notice that the voltage doesn't drop below 3.2 volts until 210 AH have been discharged. That's 77% of capacity discharged or 23% remaining. Even then it's still above 3.1 volts until it hits 240 AH or 88% discharged(12%remaining). So in other words, I'd have to already be going too low before the meter would start having the accuracy problem stated in the video you shared.

[image]


2014 Lance 992
2014 Ram 3500 DRW Turbo diesel

3 tons

NV.

Senior Member

Joined: 03/13/2009

View Profile


Offline
Posted: 04/14/21 12:51pm Link  |  Quote  |  Print  |  Notify Moderator

“ So 3 Ton, what makes you think the Victron Smart Shunt is doing anything different than the other two meters?”

FWIW, I went with a Victron BMV 12 because my faithful and otherwise perfectly good LinkLite was ‘Lost in Space’ with LFP, regardless of what settings I programmed... You seem determined to impute from a distance that this is due to either a ‘bad meter’ (or I suppose operator error??), but you’d be wrong (meaning out on a speculative limb...).... Bottom line is, Victron WORKS!!...BTW, maybe it’s just me but Will Prowse does not impress - I find his presentations invariably leave more questions begging than are answered (I have no idea about his background?) but other than that he seems like a nice fella making a living... I don’t mean to sound dismissive here, as I implied this is just my own opinion period...

Freep

Wisconsin

Senior Member

Joined: 04/14/2017

View Profile


Offline
Posted: 04/14/21 12:56pm Link  |  Quote  |  Print  |  Notify Moderator

3 tons wrote:

“ So 3 Ton, what makes you think the Victron Smart Shunt is doing anything different than the other two meters?”

FWIW, I went with a Victron BMV 12 because my faithful and otherwise perfectly good LinkLite was ‘Lost in Space’ with LFP, regardless of what settings I programmed... You seem determined to impute from a distance that this is due to either a ‘bad meter’ (or I suppose operator error??), but you’d be wrong (meaning out on a speculative limb...)....


And why would I be wrong? I'm OK with having my mind changed. But you just haven't provided any convincing evidence other than your experience with one meter that doesn't work.

3 tons wrote:


Bottom line is, Victron WORKS!!


I don't dispute that. I still don't see any evidence that Victron is determining SOC any differently than the other two meters. A claim you have made and not backed up with evidence. I'm willing and happy to change my mind but it takes evidence.

3 tons

NV.

Senior Member

Joined: 03/13/2009

View Profile


Offline
Posted: 04/14/21 01:22pm Link  |  Quote  |  Print  |  Notify Moderator

Freep, You must be having an argument with a ‘straw man’ - lol! ..,,From learned experience my position is “you usually get what you’re willing to pay for” (Victron $$).. But at least you’ve arrived at the conclusion that there IS the possibility of errors with straight coulomb counting, so we’ve made progress, eh [emoticon] , and kudo’s to you Sir if your favorite meter (unknown to me) is meeting all your expectations - sounds like you’ve saved a few bucks too!!... For ‘evidence’ you might try litigation...,


3 tons

Freep

Wisconsin

Senior Member

Joined: 04/14/2017

View Profile


Offline
Posted: 04/14/21 01:30pm Link  |  Quote  |  Print  |  Notify Moderator

3 tons wrote:

Freep, You must be having an argument with a ‘straw man’ - lol! ..,,From learned experience my position is “you usually get what you’re willing to pay for” (Victron $$).. But at least you’ve arrived at the conclusion that there IS the possibility of errors with straight coulomb counting, so we’ve made progress, eh [emoticon] , and kudo’s to you Sir if your favorite meter (unknown to me) is meeting all your expectations - sounds like you’ve saved a few bucks too!!... For ‘evidence’ you might try litigation...,


3 tons



I find your attempts to try to get personal instead of addressing the facts disconcerting. I've ignored a lot of it but now I'm going to ask you to stop.


Please address the chart and the points I presented. Also if you could point me to any evidence that Victron is using a different method than the other meters that would be great. I can't find any evidence that suggests they're doing it differently.

jaycocreek

Idaho

Senior Member

Joined: 12/28/2013

View Profile


Offline
Posted: 04/14/21 01:34pm Link  |  Quote  |  Print  |  Notify Moderator

For what it's worth,,I have checked the Victron smart shunt against the volt meter on my battery box and the silly cheap plug in meter that goes in a socket,and there all the same,every time I check but only in tenths..

I figured they would be different from everything I've read,but there not...

Freep

Wisconsin

Senior Member

Joined: 04/14/2017

View Profile


Offline
Posted: 04/14/21 01:40pm Link  |  Quote  |  Print  |  Notify Moderator

jaycocreek wrote:

For what it's worth,,I have checked the Victron smart shunt against the volt meter on my battery box and the silly cheap plug in meter that goes in a socket,and there all the same,every time I check but only in tenths..

I figured they would be different from everything I've read,but there not...


What kind of battery?

I remember when we first got the camper and I didn't know how dumb the battery level meter was. I was astounded that I could run the hot water heater and the fridge on DC while the sun was out without draining the battery. Little did I know that it was only telling me the voltage of the whole DC system! I've learned a lot since then.

3 tons

NV.

Senior Member

Joined: 03/13/2009

View Profile


Offline
Posted: 04/14/21 01:48pm Link  |  Quote  |  Print  |  Notify Moderator

“I find your attempts to try to get personal instead of addressing the facts disconcerting. I've ignored a lot of it but now I'm going to ask you to stop.”

Just because I’m unwilling to pursue argumentative rabbit holes (thats just me...) is not evidence whatsoever of me making things personal Sir (how so??), nor do I play the ever popular Victim card (time-out nonsense...) on others...

3 tons

Freep

Wisconsin

Senior Member

Joined: 04/14/2017

View Profile


Offline
Posted: 04/14/21 02:04pm Link  |  Quote  |  Print  |  Notify Moderator

3 tons wrote:

“I find your attempts to try to get personal instead of addressing the facts disconcerting. I've ignored a lot of it but now I'm going to ask you to stop.”

Just because I’m unwilling to pursue argumentative rabbit holes (thats just me...) is not evidence whatsoever of me making things personal Sir (how so??), nor do I play the ever popular Victim card (time-out nonsense...) on others...

3 tons



The bolded text above is one example.


Here are the others



Here you're deflecting and diminishing others without taking the points into account
Quote:


No, Personally I would defer to sage engineering reasoning and avoid speculation - I’m sure that other’s (novices) may go different routes...



Here you're trying to start an argument about my motives and puffing yourself up in the process.
Quote:


Well I find it kinda interesting that you’d choose to withhold that dissenting point of view ‘pending’ whatever my response was??...Having worked professionally with numerous engineers of various disciplines and opinions myself (not unlike expert Economist lol!...) while at the manufacture of Hydrogen and hydrocracking, I’ll easily stick by my previous judgement and let the free-lancers do what free-lancers do..,JMO




This is a pretty obvious dig, again trying to get personal
Quote:


Critical thinking requires all sides (dimensions)
of the story...




Again, distracting from the points and trying to impugn and question my motive
Quote:


You seem determined to impute from a distance that this is due to either a ‘bad meter’ (or I suppose operator error??), but you’d be wrong (meaning out on a speculative limb...)..



Accusatory and mocking
Quote:


Freep, You must be having an argument with a ‘straw man’ - lol! ..



I can see you're trying to start a personal argument. I would like you to stop, please.


edit: I missed one

Insulting
Quote:


. For ‘evidence’ you might try litigation...,



Edit: I would like to point out that 3 tons is displaying classic DARVO techniques.

* This post was last edited 04/19/21 02:10pm by Freep *   View edit history

jaycocreek

Idaho

Senior Member

Joined: 12/28/2013

View Profile


Offline
Posted: 04/14/21 02:27pm Link  |  Quote  |  Print  |  Notify Moderator

Quote:

What kind of battery?


Lifepo4...

I expected, because I've read, that the volt meters for lead acid were not accurate with lithium,not from what I've seen so far...I haven't drawn it down below 50% yet but above that ,there all the spot on but only in tenths for the standard volt meters..It would be interesting to them then compared in the hundreths where lifepo4 volt readings should be compared to the charts..

Just for a general idea of SOC,there very accurate to the tenth.

Reply to Topic  |  Subscribe  |  Print Page  |  Post New Topic  | 
Page of 19  
Prev  |  Next

Open Roads Forum  >  Tech Issues

 > LiFePo4 vs Lead Acid...Some points of interest.
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:




© 2021 CWI, Inc. © 2021 Good Sam Enterprises, LLC. All Rights Reserved.