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 > Your search for posts made by 'Freep' found 129 matches.

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

Well, for the record Sir I never once knocked your AiLi meter, and even stated that I was not familiar with it...But then (per your demand for ‘evidence’...) it was presumed to be incumbent on me to prove that Victron was any different that your Chinese made meter (huh??)...No doubt the Chinese have the ability to make good stuff, but owning a Victron, why should I care about comparing to a particular brand labeled AiLi, or any other brand??...There’s no need whatsoever to justify what works for you, in fact, having read the AiLi instruction link you’ve just provided, it says it’s suitable for Lithium so I take AiLi at their word, but you’d previously stated that it was strictly a coulomb counter, but that the error rate was only negligible - fair enough, but understand that I have no interest in disparaging the brand of your’s or anyone’s meter choice du jour..I did say for the broader audience that my former LinkLite had proven not compatible with LiFePO4, of which (for reasons unknown) you chose to casually dismiss as just a defective meter (Not!)...Seems (per your past pointed accusations) that you sought to call me out for ‘hidden reasons’, but it’s far better to just stick with tech matters, which is why we’re all here - JMHO 3 tons OMG, just stop.
Freep 04/19/21 05:31pm Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

The snark and derision is unnecessary. https://www.rvhabit.com/post/installing-a-full-function-rv-battery-monitor-from-aili https://static.wixstatic.com/ugd/659bdd_c04e5a349924435bbfb69ed054b065ff.pdf Actually you're setting your zero capacity voltage point rather than the full, but it's for the same purpose and of course your capacity. Ignoring the bickering, resetting at zero SOC isn't useful. Most folks rarely run their battery down to 0% SOC as it greatly shortens the life (lead) or risks a BMS shutdown (lithium), and in general you want some reserve capacity (both). So in practice this does not actually do anything. I didn't even know about the zero setting since I used the 100% setting when the battery was full and it works fine.
Freep 04/19/21 05:30pm Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

“ The snark and derision is unnecessary.”??...Snark, How so ?? (apparently only when I use your same words??)..I really don’t get it - I guess I forgot to check the box for a ‘sensitivities waiver’...:) 3 tons, in the High NV Desert, where sensitivities are not a currency Please stop.
Freep 04/19/21 02:40pm Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

There are a couple of features that make the Victron more accurate than many of the cheap-o monitors: For lithium, an important feature is automatic syncing - you can program into the Victron what your fully charged voltage and tail current is, thus when you know the battery is full, the monitor automatically syncs SOC to 100%. This compensates for integral errors, which are always an issue with Ah meters/coulomb counters. The AiLi does this. Huh??....Show ME the ‘Evidence’ !! - lol :) 3 tons The snark and derision is unnecessary. https://www.rvhabit.com/post/installing-a-full-function-rv-battery-monitor-from-aili https://static.wixstatic.com/ugd/659bdd_c04e5a349924435bbfb69ed054b065ff.pdf Actually you're setting your zero capacity voltage point rather than the full, but it's for the same purpose and of course your capacity.
Freep 04/19/21 02:06pm Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

There are a couple of features that make the Victron more accurate than many of the cheap-o monitors: For lithium, an important feature is automatic syncing - you can program into the Victron what your fully charged voltage and tail current is, thus when you know the battery is full, the monitor automatically syncs SOC to 100%. This compensates for integral errors, which are always an issue with Ah meters/coulomb counters. The AiLi does this.
Freep 04/19/21 12:53pm Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

Victron is like GO Power or like Battleborn. They came out with a quality product when there wasn't much competition and they could set their price. Now that there is lots of competition they don't want to drop their price and start ad campaigns to trash the quality of other manufactures, say because they are made in China. Well, both good and bad quality can come out of china and that depends largely on the specs the importing company gives the manufacturer. Most of Victron probably comes over in sea cans and they're good quality. My 50 buck battery monitor is the same set up as the 250.00 Victron (CDN pricing) the only thing different is the Victron has Bluetooth. Bluetooth would be worth an extra 20 to 30 bucks, but not 200.00. Steve Keep in mind that Victron offers a lot more than just Bluetooth. Many of their components coordinate with each other, Victron also uses CAN bus, have developed the Venus Operating System for their monitoring and control features and opened it up for developers and DIYers. For example, a developer can run the Victron operating system on a Raspberry Pi and create their own custom monitoring and automation. And a lot of people do this. So if you need that sort of interoperability and flexibility, it's hard to beat Victron. If you also don't mind paying the premium, then Victron is pretty much impossible to beat. With all that said, it still looks like the claim that Victron uses some special lookup table for their Smart Shunt is false. It has a lot of great features, but that isn't one of them from what I can tell. And even if it is true, with most LiFePo4 packs you'll never be able to tell the difference between counting Coulombs and counting Coulombs plus using a lookup table.
Freep 04/19/21 08:20am Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

Oh I misunderstood you, Jaycocreek. I thought you meant one of these: http://trailertraveler.net/wordpress/wp-content/uploads/2015/10/1510_Lance-Power_030.jpg
Freep 04/14/21 03:11pm Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

If those are your only specific grievances Sir (curiously deplete of important context...) then I’m completely unaware of any attempts whatsoever to ‘personally malign’ you... Remarks should be considered within their proper context ...Making such ‘a claim’ shouldn’t be taken lightly, nor does it make it a actual fact - if such was the case, I could then wantonly counter that a ‘cavalier accusation’ made somehow equals a reverse maligning, but admittedly that kinda point for point gamesmanship (as occasionally occurs with a few ‘argument-centric’ forum post) would be plain silliness.... Just my level best opinion only... 3 tons Please stop.
Freep 04/14/21 02:38pm Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

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. That is odd. You're right, the volt meters for lead should not be correct with LFP. Here's a LiFePo4 voltage chart https://diysolarforum.com/attachments/lfp-voltage-chart-jpg.27632/ Here's a lead chart https://modernsurvivalblog.com/wp-content/uploads/2021/02/battery-state-of-charge-chart_v2.jpg
Freep 04/14/21 02:34pm Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

“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 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. 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 Critical thinking requires all sides (dimensions) of the story... Again, distracting from the points and trying to impugn and question my motive 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 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 . For ‘evidence’ you might try litigation..., Edit: I would like to point out that 3 tons is displaying classic DARVO techniques.
Freep 04/14/21 02:04pm Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

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.
Freep 04/14/21 01:40pm Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

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 :) , 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.
Freep 04/14/21 01:30pm Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

“ 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. 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.
Freep 04/14/21 12:56pm Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

So 3 Ton, what makes you think the Victron Smart Shunt is doing anything different than the other two meters? 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. https://www.rj-lithium.com/photo/rj-lithium/editor/20190127230737_43073.png
Freep 04/14/21 12:12pm Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

3 tons, If you look at that thread I referenced you will see some interesting opinions on this particular issue you bring up. For example, the problem the engineer in the video you posted is talking about is a problem that doesn't really exist in our application. Also the charge/discharge curve he's using as an example is not nearly as flat as a LiFePo4 curve. The drop off in current is going to be less than the 20% mark where you shouldn't be discharging anyway. So while he is technically correct, it is an irrelevant detail in this application. This is similar to the fact that Newtonian physics was proven wrong by Relativity. Sure it's wrong, but calculus is still very useful in applications where relativity has a negligible effect. Again, I'm not seeing anything that shows the Victron is doing anything different to report on state of charge than the other meters mentioned.
Freep 04/14/21 10:32am Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

Testing an alternator vs LFP on a bench is very different than in an RV. Unless of course you have a converted bench as an RV ;) True. But if you don't use a DC-DC converter you probably should do something to avoid this.
Freep 04/14/21 10:20am Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

From https://diysolarforum.com/threads/coulomb-counter-not-strictly-compatible-with-lifepo4.21238/ well, only an old retired engineer here, so I will take a shot at making it "simple" ;) (said absolutely every engineer as they start their presentation) An amp is just a coulomb/sec or 1coulomb = 1amp * 1sec. the rate of flow of the electron does not give a hoot about the voltage so it literaly is the number of electrons that have flowed. energy is the relationship between voltage and current. if you know how many amp-seconds worth of electrons you put into something, well, when you have started to pull that many out you are running on empty. Sounds like people are trying to compare "current" and "energy"...they are related but different. the "energy" is a function of voltage * coulombs used; and therefore the potential energy in the cell is dropping as the voltage drops even with a constant coulomb draw... the flat discharge nature of the lifepo4 means that the window of constant energy draw (consistant voltage and current) is also mostly flat until the end. Once you have hit the point of rapid voltage drop you ARE getting less "energy" for the same coulomb draw; but the end is near anyway due to the sharp dropoff. Your coulomb counter is still valid, if you want to maintain a specific power output, you will draw more coulombs as the voltage drops...shunts measure coulombs and you will not get out more than you put in(if you do, quick, get a patent!!!). you can tell how long you have left before dead just by coulomb counting... If I have 200coulombs left and I am drawing them thru the shunt at some rate, then its easy to solve for 0. You could probably take the standard discharge curve of the end of the lifepo4 and create a simple two point equation from it once you hit the drop-off to actually estimate the amount of energy left. The voltage will keep changing and coulombs will increase to sustain the energy demand. Or, you can just count coulombs, when you hit zero, game over hehe You are using the energy but its really the flow of electrons you are controlling. That said, its way simpler to just accept that once you drop under 3volts, you are done. If you have been counting coulombs all along, you know how many amp-seconds you have left if you want to predict exactly how many watt-seconds remain.
Freep 04/14/21 09:47am Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

“ Do you think it would be more accurate if the meters counted Amp hours?” A few post back I added links to two engineering discussions on this very matter that helped ‘wash my mental windows’ Well worth one’s investment of time to gain a ‘beyond novice’ understanding of the difficulties in determining SOC of LFP’s - trust, not really a ‘one solution fits all’ situation...I offer this mostly to the broader audience... 3 tons Yeah but you didn't really answer the question. Do you think it would be more accurate if the meters counted Amp hours?
Freep 04/14/21 09:22am Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

“Who was it that told me” ??...It was first hand knowledge, and be advised that I’ve mentioned this before - It was my Xantrex meter... Try as I might, once below about 60’ish %, regardless of what settings I used it would not track LFP SOC with any accuracy, nor does the owners manual specify LFP...However, the Xantrex worked flawlessly for 11 years with my former GC 6v... 3 tons I think you may have just encountered a bad device. There's nothing I can find that shows the three devices use different techniques to arrive at the SOC. I have two AiLi meters. I realized I'd be pulling a large number of amps and would require a larger shunt so I got the bigger one and just swapped out the shunt and not the head unit because the head units looked identical. It turns out it wasn't and I was not getting consistent readings with the new shunt and the old head unit. Once I replaced the head unit too, everything was fine. Do you think it would be more accurate if the meters counted Amp hours?
Freep 04/14/21 08:21am Tech Issues
RE: LiFePo4 vs Lead Acid...Some points of interest.

Moot Point vs. Mute Point Moot means unimportant or not worth talking about. Mute means completely silent. Moot and mute might seem like similar words at first glance, but they are pronounced differently. Mute rhymes with cute, whereas moot rhymes with boot. Nevertheless, some people still mishear the phrase moot point as mute point. But don’t let that confuse you. The correct phrase is moot point, not mute point.
Freep 04/14/21 08:14am Tech Issues
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