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 > Your search for posts made by 'FWC' found 26 matches.

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RE: Battery monitor that connects to wifi

What is the use scenario you are looking for that you need Wifi? Broadcasting the data to the web so you can read it from anywhere? Reading the data on a local device?
FWC 01/23/22 09:46am Tech Issues
RE: this is why

It is like a broken record around here..... Let's do a quick apples to apples comparison between a $500 100Ah SiO2 Battery and a $500 100 Ah LiFePO4 battery.. The LiFePO4 battery is rated for 2500 cycles at 100% depth of discharge at 0.5C charge/discharge. Now go to the SiO2 spec sheet, in order to get 2500 cycle from the SiO2 the maximum depth of discharge is ~50%. So right there you have twice the 'usable capacity' from LiFePO4 relative to SiO2. If you dig a little deeper (page 2 of the SiO2 spec sheet), the SiO2 only has a run time of ~60 minutes at 0.5C which would yield 50Ah. However, to meet the 2500 cycle lifetime, you don't want to go below 50% SOC, so that limits you to 25Ah from your 100Ah SiO2 battery. Conclusion: LiFePO4 has 4x the 'usable capacity' SiO2 for the same lifespan for the same price. The answer is about the same if you treat the SiO2 gently, let's limit the discharge to 0.1C and 50% DOD. In which case the SiO2 gives you ~2500 cycles, but still only yields 240 min run time to 50% DOD = 40Ah. In comparison at 50% DOD the LiFePO4 yields 13000 cycles - so 5x the 'usable lifetime'. Conclusion: LiFePO4 has 5x the 'usable lifespan' of SiO2 under the same use scenario and price. The thousands of dollars saved by using LiFePO4 over SiO2 would surely be plenty of money to pay for what ever upgrades are necessary to keep the LiFePO4 batteries warm.
FWC 12/30/21 09:50am Tech Issues
RE: this is why

I am still not following - why would it taking 3 hours to heat the living quarters mean that Li would not meet you needs? Regardless of the battery chemistry, if you are going to use them in very cold temperatures, it almost always makes sense to heat the batteries. The capacity of all batteries is greatly decreased at low temperature. With FLA at -40F/C you can get about 20% of their rated capacity, with AGM/Gell/SiO2 you can get about 40%. LiFePO4 is a bit better and retains about 50% of its capacity at -40. The other big issue is battery voltage decreases with decreasing temperature and internal resistance increases, so if you are using you batteries to power something like an inverter with a high current draw and a low voltage cut off, you will only be able to use a small amount of the already reduced capacity at low temperatures. Ideally you would use the heat from the living space or a furnace vent to heat the batteries, but even if you had to use half the batteries own power for heat you would still be better off than using the batteries cold.
FWC 12/28/21 10:40am Tech Issues
RE: this is why

valhalla360, Exactly so. I'll be glad when I can get to B.C. to buy 7 or 8 SiO2 batteries. I'm still not seeing the point of your original post. - If you need a big battery bank for other purposes but will have access to shore power during extreme cold, there are simple solutions to make lithium work. - If you don't need a big battery bank and will always have shore power, just get the standard single battery and save yourself a lot of money. Maybe it would be better if you lay out your use case. Agreed. This has been described for years, but doesn't make sense to me either. Firstly it doesn't seem like the OP is planning on going camping at -40C. But if he is, it would be very interesting to see what sort of camper could survive this. A mass market RV certainly wouldn't be useable for a whole variety of reasons, lack of insulation, insufficient heat, moisture management, tanks etc. Secondly, I assume if he is planing on using the camper, he has some sort of auxiliary power and heat, shore power, a generator and a furnace with which to warm his camper. If you are actually going to inhabit the camper, humans, water and food are more temperature sensitive than any sort of batteries.
FWC 12/28/21 08:17am Tech Issues
RE: New generator technology product

Recharging in the middle of the night is not necessarily a requirement that everyone cares about. Some folks are using their 'generators' for tail gating, or running power tools, or have sufficient battery capacity relative to their consumption that this not a consideration. Other folks care about running it in the middle of then night. Again, these can replace some ICE-generators for some uses, not all ICE-generators in all uses. There are also times when this would work better than an ICE generator - you can't use a generator indoors, and in a lot of places you can't use a generator due to quiet hours. Different needs for different folks.
FWC 12/26/21 11:10am Tech Issues
RE: water filter for taste and smell

You may want to check that Pentek filter - pretty sure they are made in China ;). Simplest option is one of the inline hose thread activated carbon water filters for city water and tank filling. That won't help if the issue is your hot water heater though.
FWC 12/25/21 11:02am General RVing Issues
RE: New generator technology product

If we want to get all pedantic - these battery packs are really doing the same thing as a petrol generator, which should really be called a genset anyway. They are both converting chemical potential energy to electrical energy. The difference is in how you replenish the chemical potential energy, in a genset you pour in more chemical, in a battery pack you put it back as electricity. Now I agree it is all marketing bunk, but what isn't these days? These things can replace some petrol-powered generators in some situations, but not all petrol generators in all situations.
FWC 12/23/21 11:55am Tech Issues
RE: BEV as a toad behind diesel pusher

With auto driving also on the radar, what about not even connecting the car to the MH? It just follows along 5m behind the MH as if it were towed? No hooking up, no disconnecting, no extra length or weight on hills. With some sort of beacon on the MH for the car to follow, this seems like a much easier control problem than 'normal' auto pilot for an EV. A true self-driving vehicle wouldn't even need to stay behind the motorhome - just program in the desired destination, and the vehicle would get there on its own. Naturally, due to range limitations, it might need to meet you at designated charging stations along the way. Agreed, with true self driving there would be no need to follow along. My thought is that a follow on mode would be much easier to achieve than full self driving and gets away from some of the murky legal and liability issues with self driving vehicles. The technical challenges are far easier - just follow the huge MH in front of you and from a legal/liability issue the EV could be treated just the same way a towed vehicle.
FWC 12/22/21 05:39pm General RVing Issues
RE: BEV as a toad behind diesel pusher

With auto driving also on the radar, what about not even connecting the car to the MH? It just follows along 5m behind the MH as if it were towed? No hooking up, no disconnecting, no extra length or weight on hills. With some sort of beacon on the MH for the car to follow, this seems like a much easier control problem than 'normal' auto pilot for an EV.
FWC 12/22/21 09:17am General RVing Issues
RE: BEV as a toad behind diesel pusher

It looks like flat towing and charging an EV is on the radar: Ford patent on flat towed EVs
FWC 12/21/21 08:06pm General RVing Issues
RE: Simplest battery monitor and shunt? Advice for non-expert

As long as you don't plan on running your battery down to 0% SOC, which it sounds like you aren't planning on, then it is not really that critical to know your capacity down to the Ah. Assuming you have a 100Ah nominal battery, if you plan on regularly pulling 50Ah out, then you are running it down to 50% SOC if it is new, or 38% SOC of charge if your capacity is degraded to 80Ah. Either is totally fine. If you are really concerned about capacity, pull 50Ah out, disconnect the battery and let it sit for a few hours, then look at the voltage on your monitor, that will give you a fairly good idea what your actual capacity is. While I did bring it up, I would highly recommend NOT getting the Smartguage. While it may give very accurate SOC for a lead acid battery it will be useless when you upgrade to LiFePO4 or what ever the next great battery technology is. Secondly, shunt based monitors provide more than just the SOC. Particularly with solar, knowing the current can be really helpful - you can adjust your panels to maximize the power harvest (super easy with bluetooth). Finally it is by far the most expensive, the original smartgauge or the newer SG200 is around $300 once you add in bluetooth. If you are concerned about Peukert, the Victron monitors will account for this in their calculations. Well, I am learning a lot and have (as usual) learned myself into a corner. I was leaning toward an Amp/hour counter, like the Victron. (Am I right about that -- is that the main advantage of the Victron over the voltage-based monitors? I certainly want to know how many amp/hours I've got in the tank!) But then I went to the Smartgauge site and started to plow my way through the article Don referenced above. And I came to this significant passage: "The problem with traditional Ah or Coulomb counters is keeping them accurate. As batteries age their capacity changes, the charge efficiency changes as does the Peukert’s constant. A battery is an ever moving target, so the 100Ah battery you bought three years ago may now only be a 75Ah battery." I'm going to ignore Prof. Peukert -- I only use one battery at a time. (I know, I know -- I am leaving money on the table by not using the batteries in parallel -- but I just like the rock-solid safety of using one and holding another as a spare, just in case.) But the big problem is that I really don't know, and won't know, the true amp/hour capacity of my dumb lead-acid deep cycle battery. When it's brand-new, it's rated at 110 a/h, which means I can draw it down to about half of that without getting a pain in my anode (or whatever it is that happens when you over-discharge an old-school FLA battery). But as the article points out, FLAs degrade over time, even when we baby them by never going below 12.1 volts (or 50% state of charge). So that is now my question -- for those of you who are fans of Victron-type monitors, how do you deal with the problem of AHDS ("Amp/hour dwindle syndrome")? That article goes on to say, by the way, that you can determine if your capacity is dwindling by conducting a 20 hour load test. The author says that no one really does that, in the real world. My guess is that if you have lithium batteries, you don't have to worry about this phenomenon. Bottom line -- if actual battery capacity is a moving target, then an amp/hour counter may provide a misleading over-estimate of the remaining juice. And if I have to indulge in guesswork, I can just whip out my cheap old-school multi-meter, measure the voltage, interpolate state of charge, and call it done! Thanks again for all of the expert input - I know that this is a surprisingly touchy subject, and reasonable minds can differ about all of this. Battery care is both a science and an art!
FWC 12/17/21 05:23pm Tech Issues
RE: Simplest battery monitor and shunt? Advice for non-expert

Money is only one factor out of several. In terms of functionality the order is: Victron BMV-712 > Victron Smart Shunt > AiLi > Voltmeter > dummy lights > nothing. In terms of cost, it is exactly the opposite. If you are truly budget limited then pick what ever fits your budget. However, for most of us with $20K - 500K campers, $100 is in the noise and having a better idea how things are working is probably worth the cost. Particularly with lead acid batteries who boondock, it is important to know that your batteries are actually getting fully charged, which a meter with history will tell you.
FWC 12/16/21 09:53am Tech Issues
RE: Are chips coming available?

I read that Ford has invested to build/partner it's own Chips. Can't imagine why it took this long. A major no no in manufacturing is not having redundancy for parts supply. Lack of Chips has crippled the entire auto industry and it took 2 years for them to start finding alternative sources or making them themselves? Bizarre. I am not sure it is quite that simple. The companies that design these integrated circuits (ICs, aka 'chips') have spent decades refining their design and IP. Similarly the foundries that make these have also spent decades dialing in their processes to build transistors that are less than 10 nanometers across. The reason Ford and all the other automobile and widget manufacturers buy these parts from TI, NXP, Infineon, Samsung etc is that they don't have the experience or knowledge to make them. Sure they could partner with current ICs manufacturers to increase production, but they are unlikely to actually be designing and manufacturing their own ICs anytime soon. Not even Apple makes it's own processors/ICs, they license the architecture from ARM in the UK and have the chips made by Taiwan Semiconductor Manufacturing (TSMC).
FWC 12/15/21 01:24pm Tow Vehicles
RE: Simplest battery monitor and shunt? Advice for non-expert

The first question you need to consider is if you want a coulomb counter that directly measures amp-hours in and amp-hours out of your battery to calculate state of charge, or you want a volt meter to infer state of charge from voltage and a chart with a bunch of caveats. Many of the suggestions above are volt meters. It sounds like the OP is interested in the coulomb counter (ie with a shunt), which is a good idea. Particularly if you have solar, it is hard to interpret what the voltage means as the battery is always being charged at a variable rate during the day, so the voltage can vary wildly as a cloud moves in front of the sun. You can really only get a meaningful reading first thing in the morning. For coulomb counters there are three basic options: 1. The no-name ebay/amazon versions (AiLi, Renogy and the like). These are the least expensive option, but have some limitations, they only provide an instantaneous value without any history or configuration, and no bluetooth connection. 2. The Victron smart shunt - which is bluetooth only, is configurable and provides history and performance metrics. 3. The Victron BMV-712 which is essentially the same as the smart shunt, but includes an LCD display to mount inside the camper. There is a fourth option - the TriMetric, which was the bees knees 20 years ago but is now completely overpriced and out of date and not worth considering. My suggestion (as stated before) unless you are funds limited, go with option 2 or 3. They are a bit more expensive than option 1, but provide more useful information and are the 'standard' in battery monitors. Bit if your budget is tight, option 1 will work well enough. There is one other option, the Balmar SmartGauge, which hooks up like a voltmeter but actually measures battery capacity. It is easy to hook up and quite accurate, but is expensive and will only work with lead acid batteries.
FWC 12/15/21 08:51am Tech Issues
RE: Simplest battery monitor and shunt? Advice for non-expert

Probably the simplest option is the Victron Smart Shunt for ~$130.. The whole unit resides in the battery box with no holes to drill or wires to run. The output is viewable on any phone/tablet/computer. Victron also makes a version with a hardware display if that is important to you. There are cheaper no-name options, but they have several drawbacks - they need to have the display installed and wired up, they are less accurate and most importantly, they only provide a snapshot of what is going on right now without any history. The Victron unit provides the current state of charge, but also statistics about the performance of your battery which are very useful for determining how your systems is working.
FWC 12/14/21 03:54pm Tech Issues
RE: Some EV charging considerations…

Well said @jdc1. I can't add anymore to it with your well reasoned and fact-based post. Feel-good for purchasing an EV. Ask those who have one how happy they are and what's their next car will be or what they'll upgrade into. Hint: Never ever an ICE. Ha, Glad to know you’re feeling good Sir - You’d likely get the same short-term endorphin rush (but at a cheaper price…) by simply getting yourself a shiny new Rolex :)….However the reality is that I don’t in any way disparage the idea of EV’s so long as they can be scientifically supported by an objective ‘net reduction in carbon’ (i.e. energy) study, without such the EV foundation is fatally flawed, thus you might consider refusing a so-called ‘green tax credit’ (sadly, paid for by one’s own hard working neighbors)… 3 tons Lucky for you, there have been a number of such studies. A recent one is available here.
FWC 12/13/21 12:58pm Tech Issues
RE: 200a/hr LFP Load test results…

jaycocreek, I believe LiFePo4 are excellent--so long as it is not too hot, or too cold. As far as loading SiO2 is outstanding. Speed of charging is not an issue for me--because I'll have either six or seven as my house bank. At .25 C that means charging at 150 amps is possible--except I have nothing that could provide that much energy. I am not sure I would consider only being able to use 40% of rated capacity under a moderate load as 'outstanding'.
FWC 12/09/21 04:08pm Tech Issues
RE: 200a/hr LFP Load test results…

I find that interesting as I have been running my Iceco JP 42 compressor fridge 24/7 (33*) for quite some time..I'm at 40% SOC AT the end of the 6th day and down 58ah..Gives people an idea on how long these lfp last,compared to the same ah AGM.. Or you could use an SiO2 with similar total power. Relative to the test that the OP is describing, you would get far worse performance from SiO2. Remember when BFL13 performed exactly the same test with his SiO2 battery? He was only able to use 39Ah from his 100Ah battery with a 0.65C load.
FWC 12/09/21 12:31pm Tech Issues
RE: A different take on the popular ‘Carbon Dioxide Narrative’

How does a British politicians misleading claims about climate have anything whatsoever to do with technical issues on RVs?
FWC 12/08/21 09:06am Tech Issues
RE: I'm actually in favor of high cancelation fees....

I would strongly support a significant 'no-show' fee for public lands camping and other reservations (like backcountry and river permits). When you reserve a campsite or backcountry permit, in addition to the camping/permit fee (which should remain low so as not to be a barrier to entry) you also authorize a much larger no-show fee. If you cancel the reservation more than a few days in advance, you still loose the permit fee, but they don't charge the no-show fee as the permit/site can be used by someone else. However, if you don't show up and haven't canceled a few days before, then you loose the permit fee and they charge the larger no-show fee. I think it is important to keep the fees to use public lands low enough that they are not a realistic barrier to entry, but I am so tired of folks who reserve a $25 permit or a $50 camp site in February and then can't be bothered to cancel it later when it turns out they can't use it in August. In some cases, such as Rocky Mountain National Park, 30-40% of the back country campsites end up not being used on popular weekends because of this. Make the no show fee $250, and then there is a motivation to be considerate about those permits booked months in advance.
FWC 09/30/21 08:04am RV Parks, Campgrounds and Attractions
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