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 > Your search for posts made by 'otrfun' found 184 matches.

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RE: SiO2 Batteries and High Amp Draws

BFL13, interesting info, thanks! How low (of a SOC) can SiO2's be safely discharged on a regular basis? Your max load appears to be ~90a. Maybe I missed it, but will the voltage on your 200ah bank of SiO2's stay above the inverter's low-voltage cut-off while under a 90a (.45c) load at its minimum recommended SOC?
otrfun 05/20/22 04:12pm Tech Issues
RE: camping in the Keys

The loop is already gone but I got one!!! . . . . . . Be prepared to pay a small fortune for parking in Key west, every where you go has pay at the curb machines where you put a slip on your dash.Totally jealous you were able to make those Bahia Honda SP reservations. We tried for a week to make reservations back in Feb. Every morning at 8am EDT we waited for the 11 mo. window to open. We typically camp at the NASKW campgrounds in Key West every winter for a month or so. Were hoping to change things up with a stay at Bahia Honda. No joy. Yup, the parking in downtown Key West is expensive, limited, and tight. We always ride our bicycles downtown. You can easily ride from the Key West/Stock Island bridge to Duval St. in about 20 min. The shortest route will take you through scenic, quiet, somewhat shaded residential streets.
otrfun 05/20/22 03:14pm Truck Campers
RE: Lance TC - lithium - DC-DC charger question

One of things rarely discussed in these types of discussions is the pre-existing alternator load prior to connecting the dc2dc charger. On our Cummins (220a alternator; OEM configured, with no optional or additional electrical equipment connected) alternator load can vary from 40a to 70a. Load varies depending on the starter battery SOC and which accessories are in use (lights, a/c, etc.). It's the remaining load capacity that determines whether a given dc2dc charger can be safely powered by a given alternator. Depending on the pre-existing load, a 160a alternator can potentially handle a given dc2dc charger with more headroom than a 220a alternator.
otrfun 05/20/22 11:09am Truck Campers
RE: Lance TC - lithium - DC-DC charger question

. . . The alternator really doesn't produce anything at idle . . . Most alternators run at ~3 times engine speed. Our Cummins idles at 700 rpm or 1000-1500 set to high idle. 700-1500 engine rpm would equate to roughly 2100-4500 alternator rpm or 150-200a according to this chart.
otrfun 05/20/22 07:24am Truck Campers
RE: Lance TC - lithium - DC-DC charger question

. . . With the truck engine off, if I forget to turn off the DC-DC it still does about 14 amps from the truck battery. Goes back to 20 when the truck is turned on. Oops, it is a Chev, no isolator, I must remember to go back into the camper and turn the DC-DC off. Easy to forget if you stop to go into a store, or worse go off for a longer time. The DC-DC isolates the truck batt from the camper batt, but it does not isolate the camper from the truck unless you have a Ford. I could put an isolator in the camper somehow as others have--might save me someday.Can't imagine using our 40a dc2dc charger without a battery isolator or equivalent to automatically take it off-line when the alternator is off-line. For us, just too easy to forget. As for isolating the 7-pin pos (+), we simply disconnected it inside the 7-pin truck to TC pigtail connector. For us, it serves no useful purpose and is just a liability with the dc2dc charger online. If we did need the pos (+) for some reason, all we have to do is reconnect the pos (+) wire inside the 7-pin pigtail connector.
otrfun 05/19/22 07:26pm Truck Campers
RE: Lance TC - lithium - DC-DC charger question

What kind of connection did you use on the 2 gauge between the truck and camper.175a, 2-gauge Anderson-type connectors.
otrfun 05/18/22 07:48pm Truck Campers
RE: Lance TC - lithium - DC-DC charger question

Another factor is to keep the input voltage high enough so the DC-DC buck/boost converter can maintain the set output amps and voltage to the camper battery. This is a separate issue from fusing the input side for its wire size, and having the input wire gauge match the input amps.I think your on the right track here. For camper applications, we have the wiring of the truck, then the connector(s), pigtail and then the wiring in the camper itself. I swear my 97 Ford had 18AWG wiring! I tapped the output of the alternator and ran to a solenoid (switched on with the engine running) and 6AWG to ~1' of the 7Pin and then spliced in as large of a AWG wire as I could fit. The ground went from the 7Pin to the trucks frame. At least Lances have 8AWG wire in their pigtails, a quick look at the wire sizes used in most 7Pin cables is 14AWG. :( My NL uses 10AWG to go to the battery. Lets face it, all wire has resistance and higher currents will create higher voltage drops. Depending on efficiency of the step up charger/converter itself (which BTW 'stepping up' a voltage is difficult to do with anything resembling 'efficient') it could be easily trying to draw 50-60A on the input. However, given the wiring in the camper itself (and the batteries state of charge) the battery may never see 40A of charge current. For example I recently viewed the charge current at the battery after a 2-day trip that the PD6045Li I have in my NL was providing when I got home. ~19A at the battery. :) Personally I'm debating getting a 20A or 40A model myself. I do know that some of them have a switch/configuration option to operate at 1/2 power. :) - Mark0NL used 15-20 ft. of 10 gauge wire for the battery to converter run on our 8-11, too. Like you we got less than 20a of charge current from our 45a PD converter. We replaced the 10 gauge with 2/0 (now get a full 45a). Used 2/0 'cause we sometimes quick charge our lifepo4 using both our 45a converter and 40a dc2dc charger at the same time (85a of total charge current). FWIW, we used a 25 ft run of 2 gauge cable from our truck's battery to the 40a dc2dc charger mounted inside the TC. 43.5a alternator/battery load with 40a of charge current.
otrfun 05/18/22 06:46pm Truck Campers
RE: New to lithium battery

otrfun, while I don’t use a dc2dc charger, thanks for expanding on this topic, and for the worthy additional in site - also I agree with your statement on LFP charging voltage (e.g. not to exceed 14.6v) being up to the user - Great points! 3 tonsYou're welcome, thanks!
otrfun 05/15/22 09:27am Tech Issues
RE: New to lithium battery

You will never get a 100% charge without a DC-DC charger.Why would you need or want a 100% charge (14.6v) to begin with? Unlike lead-cell batteries, lifepo4's subjected to 100% SOC (14.6v) on a constant, short-term basis experience reduced cycle life. 13.6v will still net 99% SOC (and a higher cycle life), although at a slower charge rate. Long-term float at =>14.6v can permanently damage a lifepo4. I never said anything about long term float at that voltage. The point of a DC-DC charger is to give the correct voltage at the correct time during the charging cycle.No, you didn't. I mentioned it because it's one of the potential consequences of charging a lifepo4 to 100% SOC with a single-stage converter. Something you failed to mention. In your previous post, you stated 1) "You will never get a 100% charge without a DC-DC charger. Above you state 2) the primary point (or mission) of a dc2dc charger is to provide the "correct voltage at the correct time during the charge cycle". 1) Ref charging a lifepo4 to 100% SOC, many folks make the false assumption that a lifepo4 must/should be charged to 100% SOC (14.6v) like a lead-cell battery. The fact is, a lifepo4 experiences a reduction in cycle life the longer it sits at 100% SOC (14.6v). If it floats at 14.6v long enough it can be permanently damaged. 2) Ref your comment about "correct voltage", the correct voltage is ultimately up to the user---as it should be. Renogy dc2dc chargers are one of the most widely used dc2dc chargers because of their low-cost. It allows the user to choose various absorption/float charge voltages ranging from 12.6 to 14.7v. Surprisingly, if you choose the "lithium" mode, it will only operate as a single-stage charger. As a single-stage charger set to charge to 14.6v (100% SOC), it will charge at 14.6v indefinitely---the worst possible way to charge a lifepo4. This is why I mentioned the dangers of long-term float at 14.6v while a lifepo4 is at 100% SOC. This is precisely what may occur if you leave it up to the Renogy dc2dc charger to provide the "correct voltage at the correct time during the charge cycle" while charging in lithium mode. Fortunately, Renogy provides a 2-stage absorption/float mode in their dc2dc chargers which can be used to charge a lifepo4, safely and fully. I find it ironic it's a recommended setting for lead-cell batteries. Progressive Dynamic's first generation of lithium converter/chargers were/are single-stage units. It's telling that they are now transitioning to multi-stage lithium converters. I also find it ironic (and sad), that so many folks spend their hard-earned money upgrading to so-called "lithium approved" converter/chargers when in many cases their existing 3-stage lead-cell converter/charger will actually do a safer and better job of charging their lifepo4.
otrfun 05/15/22 07:30am Tech Issues
RE: New to lithium battery

Goggles 14.6 volt figure merely refers to the upper charge limit before BMS protective cut-off…From my own experience, LFP’s are happy to charge even in the high thirteensYou will never get a 100% charge without a DC-DC charger.Why would you need or want a 100% charge (14.6v) to begin with? Unlike lead-cell batteries, lifepo4's subjected to 100% SOC (14.6v) on a constant, short-term basis experience reduced cycle life. 13.6v will still net 99% SOC (and a higher cycle life), although at a slower charge rate. Long-term float at =>14.6v can permanently damage a lifepo4. If you're the set-it and forget-it type, a 14.6v single-stage "lithium approved" converter/charger is the worst thing you can use to charge a lifepo4.
otrfun 05/14/22 10:06am Tech Issues
RE: Lifepo4 float setting?

I'm still confused about float with LFP batteries..Is it better to be in float or bulk the majority of the time? Off-Grid Garage say's one should set float and bulk the same therefor it is in bulk mode charging when the sun is out vs floating or using battery capacity..What are you striving for? Absolute max cell longevity? Max usability/ah capacity? Or, somewhere in-between? If you want absolute max cell longevity float a 12v lifepo4 at ~13.15V (~50% SOC). Downside, minimal usability/ah capacity. If you want max usability/ah capacity, float the battery between 13.6 - 14.4v (~99 SOC). Downside, some reduction in cycle life. More so as you approach 14.4v. Floating at 14.6v is not recommended. Can't have your cake and eat it, too. Pick your poison.
otrfun 05/13/22 08:51am Tech Issues
RE: My AGM to Lithium conversion

Should be required to have a sign on the side of the RV warning about Lithium batteries on board. Life has it's benefits and everything has a trade off. To me sometimes the trade off is too costly. Not talking about the initial cost, I'm talking about the danger involved with use and the eventual problems with recycling. I believe in keeping it simple, have a little more physical labor in life it's better for you.Lead acid batteries off-gas highly toxic, extremely flammable hydrogen sulfide gas. The sulfuric acid inside a lead-cell battery (if splashed) can cause serious eye injuries. Lead used in lead-cell batteries is a known carcinogen that causes a number of very serious health issues. Put in this context, got to wonder why there isn't a warning sticker on the side of every internal-combustion vehicle on the road. As for lifepo4's, they have zero off-gassing issues. To my knowledge (unlike lead-cell and some lithium-ion batteries) none of the materials used in lifepo4 cells are toxic. Also, all the *external* thermal runaway issues that exist with standard lithium-ion cells (i.e., fire/flames exiting the battery case) do not exist with lifepo4. A lifepo4 battery has superior chemical and thermal stability vs. a run-of-the-mill lithium-ion battery. Bottom line, lifepo4 can experience some small amounts of *internal* thermal runaway, but it won't exit the case. Yes, there is a YT video showing a lifepo4 experiencing arcs and flames when pierced with a metal spear. Any battery will experience this if internally short circuited using conductive metal. The same effect, externally generated, can be experienced by simply shorting the neg and pos terminals of any battery.
otrfun 05/03/22 10:57am Tech Issues
RE: Maxxfan delux latent power draw

There’s a number of small items in our truck camper that have a parasitic draw when off (dvd player, maxxfan, OTR antenna, safety sensors, etc.). Total parasitic is about .5a. We rewired our OEM battery switch from a partial to total disconnect which nets us zero parasitic when we store our TC.
otrfun 04/27/22 11:09am Truck Campers
RE: Lithium and México

México is making more and more noise about their gigantic deposits of lithium. Statements like "México has more lithium currently recoverable than the rest of the world put togther" Sounds like burro apples to me. But since the country has the worlds largest battery plant (LTH) and is the largest supplier of lead, it means they have all the equipment to do open pit mining on a massive scale. They can ship titanic size equipment on railroad flat cars directly to a mine. Then ship the ore via gondola cars to the processing plant To me this is great news. It will put Caterpillar workers back to double shifts. Vastly increase the need for battery control modules, eliminate the need for ocean going containers and ships, reduce delivery time, and last but not least employ several thousand workers, perhaps tens of thousands. ¿Quien Sabes?Ganfeng (a Chinese company) supplies 24% of the world's lithium. Ganfeng also has exclusive mining rights to some of Mexico's largest lithium deposits---at least for the time being. Mexico is giving some thought to nationalizing their lithium industry. It'll be interesting to see how all this plays out.
otrfun 04/21/22 03:16pm Around the Campfire
RE: My AGM to Lithium conversion

When I first posted on this thread it was all 80/20 or 90/10 talk compared too...I simply mentioned why not use 100% as most manufacturer batteries have a cycle count for..Some people may choose to use it all or very close to it without harm...If a user needs 102ah,it's there for use without worry whether he trips the LVD or not... . . . . These numbers are loosely based on a lifepo4 cell manufacturer's spec sheet I saw a few weeks ago. More to show cause and effect relationships than anything else. Cycle life defined as number of xx - xx% SOC cycles a cell/battery can sustain before the ah capacity drops to 80% of its original rated capacity. 30-50% = 10,000 cycle life 20-80% = 5,000 cycle life 10-90% = 4,000 cycle life 0-100% = 3,000 cycle life Another factor in cycle life is charge and discharge c rate. Go high, cycle life goes down. Go low, cycle life goes up. Exposing the battery/cells to excessively cold or hot temperatures while operating at higher c rates will also reduce cycle life. Ideal temp is 75-77f. Using a lifepo4 battery/cell, in any way, reduces its cycle life. Pick your poison--lol!
otrfun 04/16/22 03:57pm Tech Issues
RE: Converter/Charger Questions.

Charging to 100% is not desirable for Li, if you wish to have maximum cycle life. Neither is float charging.Float charging like lead-acid above the resting voltage is not the best for LFP. Properly floating 100mV to 200mV below resting is no problem at all. That would be 13.2 on a 12v LFP that would ordinarily rest at 13.4 volts and will not affect longevity. This is part of the reason "lithium" converters do not work well with LFP batteries. Many will float at 13.6 to 14.6 volts and reduce the life.There are compromises no matter how you use a lifepo4. Users can choose to focus on max longevity, max charge/discharge performance, or anywhere in between. Focus on max charge/discharge performance (high c charge/discharge) and get 1000 - 2000 cycles. Focus on max longevity (low c charge/discharge) and get 3000 - 4000 cycles. 1000 cycles, the worst case scenario, will net the average user at least 10-15 years of use before the battery experiences a 20% reduction in ah capacity. In this context, are elaborate charge/discharge protocols really all that necessary or important?
otrfun 04/16/22 09:38am Tech Issues
RE: My AGM to Lithium conversion

Clean install, Rbertalotto! Kudos to you for taking the time to post the narrative and pics. It gives other DIY'rs options, ideas, and hopefully the confidence, to jump on-board the lifepo4 bandwagon, too.
otrfun 04/16/22 07:36am Tech Issues
RE: Converter/Charger Questions.

If you are comfortable with the knowledge that these batteries can catch fire then go for it. Tesla's have Lithium Ion batteries and some catch fire. Just like those things the kids ride around on today, they can catch fire. Phones catch fire some times. That's why they don't recommend leaving them plugged in to charge over night while you are sleeping. Li-ion batteries are very sensitive to high temperatures. I use an AGM with a good amp hour rating and I don't worry.This has been debated at length. This is not a concern with lifepo4 cells. It's a different chemistry from the lithium cells you're referencing. Do you have a link showing a single instance of self-induced thermal runaway happening outside a lifepo4 cell? Would love to see it. BTW, if you're YT fan, puncturing the outer case of a lifepo4 cell with a metal spear does not constitute self-induced thermal runaway outside of a cell. That's equivalent to puncturing the gas tank on a vehicle and having it explode. What's the point?
otrfun 04/13/22 06:35pm Tech Issues
RE: Converter/Charger Questions.

Concur with time2roll's comment: Many to most "lithium" converters are not really good for lithium. It's a very common misconception that a "lithium approved" converter is necessary to safely charge a lifepo4 battery/cells. Not true. A typical, late model 3-stage lead-cell converter produces 13.2v/13.6v/14.4v. They will safely and fully charge a lifepo4 battery (only exception are WFCO's; they charge safely, but may not charge to 100%). There is nothing inherently magical or special about most "lithium approved" converters except the 14.6v bulk charging voltage. Some may find this to be somewhat of an eye-opener, but you actually risk over-charging a lifepo4 battery if you float it with a single-stage "lithium approved" 14.6v converter for long periods of time. There is NO such risk with a lead-cell 13.2v/13.6v/14.4v converter. For two reasons. They bulk charge at a lower, safer voltage (14.4v), plus they drop down to 13.2v/13.6v float/absorption mode---preventing any chance of overcharging. If you feel the need to upgrade to a "lithium approved" converter, seriously consider purchasing a multi-stage (typically 2-stage) lifepo4 converter. They typically bulk charge at 14.6v, then float at 13.6v. Stay away from any and all single-stage units. P.S. Don't blindly buy into the simple notion that one must charge at 14.6v in order to charge a lifepo4 to 100% SOC (vs. 99.9% SOC at 14.4v). Unlike lead-cell batteries, lifepo4 do better when they are NOT sitting around at 100% SOC. So, what's the point---what do you gain by charging at 14.6v? To my knowledge, not a single thing (except maybe a few seconds reduced charge time and a few seconds of additional discharge time).
otrfun 04/13/22 03:00pm Tech Issues
RE: Truck Camper Wiring Diagram

Never found a "standard" route for the 7-pin 12v pos power in a TC or TT. Some manufacturers route it through a battery cut-off switch, some don't. One way or another it's simply paralleled with the converter output, the battery, or anywhere in between. Some manufacturers use resettable fuses on this circuit, some don't. The 7-pin pos power should be fused somewhere in the TV. Although I've seen the 7-pin 12v pos power wire(s) (in a TC or TT) routed to the AC/DC power center (where it may get paralleled with the converter output), it's not typically routed through any of the ATO/ATC fuses used in most DC fuse panels.
otrfun 03/30/22 04:30pm Truck Campers
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