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RE: batteies
And to think, the OP just wanted to know if he could put Li batteies in his camper…..:SActually the OP (ck1246) only had a question about using his current converter. Everything was reasonably on topic until these last two posts about thermal runaway.
My house batteies went bad this winter. Can replace with lithium batteies. Will they work with my converter?
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otrfun
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04/02/23 06:52pm |
Tech Issues
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RE: Make line on driveway for camper loading?
Wow, gotta be more than "50 ways to" load your camper--lol!
We attach strings between the front/rear jack legs on each side, using wide painter's tape--takes about a min. As we backup, we use the ends of all four torklift extensions, the strings, and jack legs as guides. Since this is a 4-point approach, it's makes it easier to get an accurate parallel and side-to-side alignment between the truck and camper. Usually 1 or 2 corrections and we're in. Works great for us! YMMV.
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otrfun
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04/01/23 04:54pm |
Truck Campers
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RE: batteies
. . . maybe you can explain this, is why it is such a big deal to have a second stage. When I am camping in the bush the charge isn't running, so it's no big deal. With LiFePo4 everyone is so adamant about not storing them at a full charge so we shouldn't be leaving them on charge anyways when we are not using the unit. and the final category if you camp in power sites mostly, well then why did you spend money on LFP? and if you only camp with power once and a while, just turn off the charger breaker and you don't need to worry about it . . . No, not necessarily do you need 14.6v, for instance my BMS will start balancing at higher than 13.6V but for me the cell manufacture recommends charging at a constant 14.6 and then cutting the voltage when the state of charge is reached. Considering they are one of the biggest prismatic cell manufactures, I would assume they know what they're talking about and that is how I set up my system. I do play with it to see how it behaves in different situations though . . . . Not sure if you realize it, but all this monitoring, "cutting the voltage" and "turning off the charger breaker" that you recommend doing while using a single-stage 14.6v converter would not be necessary with a 2-3 stage converter. IMO, a converter should be able to safely and efficiently charge/maintain a lifepo4 battery for weeks, months at a time . . . with ZERO user input. This is exactly what a multi-stage (2-3 stage) converter does well.
StirCrazy, here's a simple analogy that hopefully answers your question why I feel a converter with 2-3 stages is a really a "big deal" . . . and why a single stage 14.6v converter is such a bad deal.
Using a single-stage (one voltage) 14.6v converter to charge a 12v lifepo4 battery is roughly equivalent to driving a car at redline. To clarify, 14.6v subjects the cells in a 12v lifepo4 battery to 3.650v---the Maximum Rated Charge Voltage for 3.2v lifepo4 cells . . . this is roughly equivalent to driving a car with a Maximum Rated RPM (redline) of 6000---at 6000 RPM. Sure you can drive a car at redline for short periods of time. You can also charge (float) a lifepo4 battery at its maximum rated charge voltage for short periods of time, too. No immediate damage occurs in either case. However . . . common sense says . . . "redlining" a car or subjecting a battery to its maximum rated charge voltage, for extended periods of time (accidentally or otherwise), presents a much higher risk of permanent damage occuring. If you're the set-it & forget-it type, and forget to turn-off a single-stage 14.6v converter while using FHU's for a month or so, you run the risk damaging your lifepo4 battery. For folks like yourself who monitor their battery & converter closely, this risk is lower. However, I would surmise most folks would prefer not to be babysitting converters and batteries while they're on vacation---I know we'd prefer not to.
In any event, NONE of the above risks exist when charging with a 2-3 stage converter (with the proper voltages)---even if the converter and lifepo4 battery are left unattended for weeks, months at time. It negates these risks by automatically activating a completely safe, lower float voltage as soon as the lifepo4 battery is fully charged.
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otrfun
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04/01/23 09:53am |
Tech Issues
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RE: batteies
When I'm plugged in my battery will not charge fully but that is not a problem with lithium.be careful saying that. yes, I agree it doesn't have to be charged fully on a regular basis, but you still have to charge it full once and a while to ensure the cells stay balanced.
You can get away with this because you let your solar charge it with proper profiles and hopefully you take it up to 100% with that once and a while and let it fully balance. My BMS has a passive balancer that would take forever to balance so I added an active balancer to mine, so it only needs 2 hours or less to balance my 300AH battery. When I am camping, I do this once a week, the rest of the time I cut off at 90% but that's the BMS controlling that.Tom_M didn't mention what voltage his converter or solar charger is using to bulk charge with. Without this information there's no way to know definitively what's going on with his system.
Also, in a number of your posts you seem to allude that you must have 14.6v to properly balance a 12v lifepo4 battery. This is not true . . . unless the BMS's threshold voltage for balancing is set too high. A 12v lifepo4 battery bulk charging at 14.4v (equivalent to a 3.600v parallel top-balance) should be more than enough voltage delta to allow a BMS to balance in a timely manner. If it's not, then you probably have bigger problems (see next paragraph). For what it's worth, Battleborn lifepo4 batteries are capable of supporting all BMS balancing functions when bulk charged at 14.2v - 14.4v (14.4v recommended). As you know, BB does not recommend long-term bulk charging at 14.6v.
Yes, an active balancer, especially a 5-10a version, will balance rather quickly. However, if you have properly top-balanced, "matched" cells, the 100-150ma passive balancer found on most BMS's should balance in a reasonable amount of time. If the 100-150ma passive balancer is not capable of doing so, then an active balancer may be compensating for, or putting a band-aid on, the true problem: moderately to badly mis-matched cells. No amount of top-balancing, passive balancing via BMS, or use of an active balancer can correct this problem. The end result, permanently reduced ah output from the battery---especially during high c discharges.
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otrfun
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03/30/23 02:44pm |
Tech Issues
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RE: batteies
It's a common fallacy that a so-called "Lithium/Lifepo4 Approved" converter must be used to charge Lifepo4 batteries. Absolutely, not true. I posted this in another thread:
. . . arguably one of the better general-purpose, non-programmable charging platforms for a lifepo4 (as long as no charge/equalization mode exceeds 14.6v) is a 3-stage *lead-cell* 13.2v/13.6v/14.4v converter. It even has the advantage of a 13.2v float and more conservative 14.4v bulk vs. some of the 2-stage 13.6v/14.6v Lithium/Lifepo4 Approved converters.
. . . there will always be some debate about the best float/absorption/bulk voltages to use with a multi-stage converter to best charge a lifepo4. However, you'd be hard-pressed to find much debate about the best one, single voltage to both float and bulk charge a lifepo4. Why? Because such a voltage simply does not exist. This is why a single-stage (single/one voltage) 14.6v converter (even though Lithium/Lifepo4 Approved) is the worst possible charging platform for a lifepo4.
Claims that a given converter/charger is "Lithium/Lifepo4 Approved" are simply marketing ploys which tell you absolutely nothing about how well or safely it will charge and maintain your lifepo4 battery. The number of stages, and the voltage used by a converter to support each of these stages, ultimately determines how well a given converter will properly maintain (and charge) a lifepo4 battery.I don't think it is absolutely true, in fact I agree that you can get by without one but should you... I think you can but only long enough till you can figure out exactly what you need then do the switchover. There are going to be some things you can't do properly without a constant voltage that is high enough, but here is my switch up. If you have enough solar, and your solar capacity is large enough to keep everything charged, then who cares about the charger on the converter... turn the breaker off, you don't need it. Then later when you decide you want to spend money you can change it out.
People seem to get hung up on this, but really, it's a couple hundred dollars, you're spending a couple K on batteries is it really a stretch to get a proper converter for them?
I look at this more as what do I need to get the maximum life out of that battery. I don't care if it will last for 15 years, I want 20 out of it. but when I was first looking into getting LI batteries most manufactures were saying to run your converter on a "Gell" setting as it is closest to a LI profile until you get a proper charger.StirCrazy, you completely missed my point.
My post mentions specific "numbers" to look for when choosing the best converter to charge your lifepo4. Things like number of stages (1-3) and specific voltages (13.2v/13.6v/14.4v/14.6v).
If the goal here is to truly help someone choose the "best" converter for charging their lifepo4 battery, these "numbers" must be discussed. A "Lithium/Lifepo4 Approved" sticker or marketing claim means little to nothing. Outside of your claim that one must use a "constant voltage that is high enough", you offer nothing that would help someone choose the "best", or as you put-it, "proper" converter.
Here are voltage and stage specs for the most commonly available, off-the-shelf, RV converters:
14.6v one (single) stage converter
13.6v/14.6v two stage converter
13.2v/13.6v/14.4v three stage converter
Clearly, one of these converters has numbers that do a much better job of "pampering" a 12v lifepo4 than the other two. Care to guess which one it is?
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otrfun
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03/30/23 11:48am |
Tech Issues
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RE: batteies
^No, say it ain’t so….lol.Don't blame you for lol. For folks like yourself that visit here often, yeah, replies like this get redundant. However, it's a simple theme---numbers trump words and stickers. Bears repeating because it comes up often. If I can save one person $200, it's worth it.
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otrfun
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03/29/23 08:28am |
Tech Issues
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RE: batteies
It's a common fallacy that a so-called "Lithium/Lifepo4 Approved" converter must be used to charge Lifepo4 batteries. Absolutely, not true. I posted this in another thread:
. . . arguably one of the better general-purpose, non-programmable charging platforms for a lifepo4 (as long as no charge/equalization mode exceeds 14.6v) is a 3-stage *lead-cell* 13.2v/13.6v/14.4v converter. It even has the advantage of a 13.2v float and more conservative 14.4v bulk vs. some of the 2-stage 13.6v/14.6v Lithium/Lifepo4 Approved converters.
. . . there will always be some debate about the best float/absorption/bulk voltages to use with a multi-stage converter to best charge a lifepo4. However, you'd be hard-pressed to find much debate about the best one, single voltage to both float and bulk charge a lifepo4. Why? Because such a voltage simply does not exist. This is why a single-stage (single/one voltage) 14.6v converter (even though Lithium/Lifepo4 Approved) is the worst possible charging platform for a lifepo4.
Claims that a given converter/charger is "Lithium/Lifepo4 Approved" are simply marketing ploys which tell you absolutely nothing about how well or safely it will charge and maintain your lifepo4 battery. The number of stages, and the voltage used by a converter to support each of these stages, ultimately determines how well a given converter will properly maintain (and charge) a lifepo4 battery.
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otrfun
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03/28/23 08:16am |
Tech Issues
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RE: LiFePO4 Converter Change?
I would not want to float an LFP above 13.4 volts. 13.2 - 13.3 is better. I don't know anyone that recommends holding LFP long term at 100% charged.
14.6 is also higher than necessary and is more likely to cause a fault in some lower cost brands from CN that many look at.
This generally gives the standard PD or the PowerMax with adjustable voltage an advantage. Both drop to 13.2 volts for long term.
That is my opinion. Good luck to the OP.Very much agree, time2roll.
Some may find it surprising, but a 3-stage *lead-cell* 13.2v/13.6v/14.4v converter probably does the best job of accommodating the voltages you've mentioned. IMO, it's arguably one of the better general-purpose, non-programmable charging platforms for a lifepo4 (as long as no charge/equalization mode exceeds 14.6v). Even has the advantage of a 13.2v float and more conservative 14.4v bulk vs. some of the 2-stage 13.6v/14.6v Lithium/Lifepo4 Approved converters.
Claims that a given converter/charger is "Lithium/Lifepo4 Approved" are simply marketing ploys which tell you absolutely nothing about how well or safely it will charge and maintain your lifepo4 battery. The number of stages, and the voltage used by a converter to support each of these stages, ultimately determines how well a given converter will properly maintain (and charge) a lifepo4 battery.
Last, but not least . . . there will always be some debate about the best float/absorption/bulk voltages to use with a multi-stage converter to best charge a lifepo4. However, you'd be hard-pressed to find much debate about the best one, single voltage to both float and bulk charge a lifepo4. Why? Because such a voltage simply does not exist. This is why a single-stage (single/one voltage) 14.6v converter (even though Lithium/Lifepo4 Approved) is the worst possible charging platform for a lifepo4.
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otrfun
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03/25/23 09:29am |
Truck Campers
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RE: LiFePO4 Converter Change?
power max is top of the line.I don't know about that.. I have been looking at it and I see a lot of mixed reviews and their power factor is commonly referred to as being bad. I do like the fact that you can fine tune the top voltage but I wish you could tune the 2nd stage independently.
With some solar controllers you can program everything. Why hasn't anyone done this for converters yet?
SteveDo you have one? I don't think the adjustment holds for the multistage. I read PM is either fixed voltage adjustable or preset multistage.We just purchased a new 75a Powermax. The unit can be switched to operate as a single-stage charger (i.e., power supply) or 3-stage charger.
There's a very small pot that adjusts voltage for *both* the single-stage mode and the *bulk* stage when in 3-stage mode. It can be adjusted from 13.0 to 16.5v. Comes from Powermax preset for 14.6v. Haven't confirmed it yet, but I believe the float (13.2v) and absorption (13.6v) voltages remain fixed and are not changed by this pot.
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otrfun
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03/23/23 03:30pm |
Truck Campers
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RE: LiFePO4 Converter Change?
I think part of that is they were waiting for a consensus of what would be good for a second voltage on a two stage and to see which format (chemical composition) was going to become the leader for rv use. There are some companies that came out with 2 stages right off the bat.I'm a bit surprised any reputable converter/charger manufacturer would produce a single-stage 14.6v lifepo4 converter/charger.
The converter/charger industry transitioned from single-stage to multi-stage converters/chargers for lead-cell batteries many, many years ago.
Lead-cell and lifepo4 chemistries share the same, exact charging dilemma. There is no one, ideal charge voltage for lead-cell. There is no one, ideal charge voltage for lifepo4.
Why some converter/charger manufacturers completely ignored this simple concept by introducing single-stage (single voltage) lifepo4 converters/chargers for lifepo4's is beyond me.
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otrfun
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03/23/23 11:42am |
Truck Campers
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RE: LiFePO4 Converter Change?
^ Are single stage battery chargers of any flavor a thing anymore? Whether talking converters, typical automotive chargers, marine chargers or small power equipment chargers/maintainers…
Every charger I’ve bought for the last 20lbs years has been a smart charger (well except the WFCO, it’s the Dollar Store of battery chargers and it came with the last RV I bought and it purports to be a smart charger as well. It’s just learning disabled…hence the recommendations here to get something else).In the lead-cell world, I agree.
In the lifepo4 world, not so much. Look closely at the "lithium/lifepo4 approved" converters and chargers now on the market. Many are single-stage (single voltage) 14.6v chargers. For instance, Progressive Dynamic, one of the largest OEM converter/charger manufacturers for the RV market, didn't start offering multi-stage (multi-voltage) lifepo4 converters/chargers until a year or so ago. There's still a large inventory of single-stage Progressive Dynamic lifepo4 converters still being sold.
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otrfun
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03/22/23 01:51pm |
Truck Campers
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RE: LiFePO4 Converter Change?
I just want to switch from lead acid to lithium, not upgrade wires and everything else. Finding a new replacement board for my WF-8955PEC seems to be complicated. Straight 14.6V continuous boost single phase vs. 14.6 boost and 13.4 idle dual phase approach, some have a switch for LA/Li, others are auto sensing, still others are Lithium only. Huge range of prices indicates there may be some poor quality fake/unauthorized parts out there. I don’t want to replace the entire thing, just the converter section.
Reading forum posts from many sites usually ends in discussions that go into the weeds quickly. Can anyone cut through it and keep it simple?It's unfortunate you have a WFCO. Even with significantly discharged batteries, they're notorious for rarely charging in the higher voltage bulk mode. They tend to stay in 13.6v absorption mode, which increases charge times. The WFCO you currently have will safely charge a 12v lifepo4 battery to 98-99% SOC at 13.6v. However, it'll take much longer to do so vs. a converter with the same current rating charging at 14.4v or 14.6v.
You may want to look at the Powermax PM3 MBA series converters. They're designed to be a plug and play replacement for the lower tray 8900 series converters that are used in many WFCO power centers. They're lifepo4 compatible and can be switched to operate in either a single-stage (power supply) mode or a standard 3-stage charging mode. The single-stage (power supply) or 3-stage bulk mode voltage can be adjusted from 13.0 - 16.5v. Since there's always ongoing debate about the optimum charge voltage for a 12v lifepo4 battery, this feature allows you to accommodate whatever lifepo4 charge voltage happens to be the "best" this week, next month or next year.
Regardless which brand converter you eventually decide on, highly recommend *not* purchasing a single stage 14.6v converter. If you inadvertently float a 12v lifepo4 battery at 14.6v (100% SOC) for long periods of time you may risk damaging the cells. Purchase a 2-3 stage converter. A 2-3 stage converter will always decrease charge voltage (go into absorption/float mode) so you never have to be concerned about overcharging and damaging the cells. Your expensive lifepo4 battery will thank you.
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otrfun
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03/18/23 12:24pm |
Truck Campers
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RE: Honda 3000
Thanks for the input. I'll have to check on BTU's.
The Shasta is a retro but I think my Brother changed out the A/C unit for a bigger one because the one it came with wouldn't cool the camper.
We are in flat land in Texas. Altitude isn't an issue here.Without knowing the continuous current rating and LRA of both a/c units it's hard to answer your question with any degree of accuracy.
BTU ratings only provide a very general idea how much power a given a/c unit may need to start/run. Some a/c units can be significantly more efficient than others---even when they have the same BTU rating. It's too bad RV a/c manufacturers don't provide a SEER rating. SEER ratings, found on nearly all residential a/c units, specify how efficient they are.
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otrfun
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03/17/23 11:02am |
Truck Campers
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RE: Lithium batteries and microwave use
. . . My specific question is, are the characteristics of lithium batteries sufficiently different from FLAs that 200 Amp hours of lithium batteries with at least a 200 amp BMS will operate the microwave without voltage sag causing inverter under-volt alarm or shutdown?
Should be, is not a helpful answer.Here's a lifepo4 C rate discharge curve at 25c (77f) that may help you better understand the voltage drop that occurs while powering a microwave with a lifepo4 battery. Multiply the voltage in the graph by 4 for a 12v lifepo4 battery. Smaller .7cf microwaves will draw approx. .5c using a 200ah lifepo4 battery. The average microwave will draw .6c - .75c.
As a lot of folks have already confirmed, a 200ah lifepo4 battery with a 200a continuous rating will power a microwave. The only thing that can derail your plan is voltage drop due to the use of too small of cabling. As long as the voltage drop between the battery terminals and the input to the inverter remains below 2% (at 150a) you should be able to access almost the full ah capacity of the battery. Inverters typically start experiencing low voltage alarms (and cut-off) when the input voltage drops below 11v. Assuming less than 2% voltage drop, you should be able to power a microwave with a 150a draw down to 5-10% SOC with a 200ah lifepo4 battery before the inverter low-voltage alarm activates. This equates to a bit more than an hour of runtime.
We use a 200ah lifepo4 battery to power our 11k BTU a/c unit (and small microwave). They both draw roughly the same current (105-110a via inverter). While powering the a/c, we've inadvertently discharged the lifepo4 down to low-voltage cut-off (2.7v at cell level or 10.8v overall) many, many times. After two years of doing so, we've never experienced an inverter low-voltage alarm or shutdown.
https://i.imgur.com/icbp8MFl.jpg
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otrfun
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03/13/23 08:15am |
Tech Issues
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RE: Lithium batteries and microwave use
. . . Does anyone have experience operating the microwave with 200 Ah of lithium?Important to note, Ah (amp-hour) and A (amp) are two different ratings.
A 200 Ah lifepo4 battery with a 100 A continuous current rating will not run the vast majority of microwaves. A 200 Ah lifepo4 battery with a 200 A continuous current rating will run most any microwave.
A similar caution applies if you have plans to parallel two 100 Ah lifepo4 batteries to obtain 200 Ah. Make sure *both/each* of these two 100 Ah batteries have a 100 A continuous current rating (*not* 50 A). Two 100 Ah batteries, each with a 100 A continuous current rating, paralleled together, will provide 200 A of continuous current.
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otrfun
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03/12/23 07:30pm |
Tech Issues
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RE: Lithium Battery heater
IMO, it's just a matter of time before all 12v, consumer-grade, lifepo4 batteries come standard with internal heating pads. It's far from rocket science, plus the costs for manufacturers to add a few silicone heating pads and a BMS with a heating pad terminal are minimal. Consumers wanted low-temperature cut-off, they got it. Internally heated batteries are next.
On a sidenote, some may not know that cold weather operation of lifepo4 batteries negatively affects discharge performance in addition to charge performance. Dropping the temperature of a lifepo4 battery from 77f to 32f can reduce the battery's total ah output by approx. 10%. This means a battery that produces 100ah at 77f may only produce 90ah at 32f. Not only is the ah output reduced, the maximum continuous discharge current the battery can safely produce is also reduced. In other words, powering a microwave while your lifepo4 battery sits in sub-freezing temps may not be doing your lifepo4 battery any big favors.
During the winter we keep our lifepo4 internally heated to a constant 55-60f (cell temps), 24/7. We do this to: 1) maximize ah output (any increase here helps power the heating pads), and 2) lower the risk of reducing cycle life with any high current discharges. Plus, it goes without saying . . . we also retain full charge capability, 24/7, too. For us, a win-win-win.
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otrfun
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03/05/23 07:58am |
Tech Issues
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RE: A happy ending?
I sometimes wonder if GEICO's approval of Pavel's claim (snapped frame on his Ram 3500 dually) was a one-time marketing decision. With his photos going viral, they knew approving this particular claim would generate free, positive publicity for GEICO---more than enough to make up for the $17k payout. GEICO knows they're under no obligation to approve any future claims of this type in the future.Nope, it’s just insurance. You’re trying too hard here too….
No wonder stupid human tricks like breaking your truck in half go “viral”. It ain’t just the Instagram generation…..
Well, that and you actually have no idea what you’re taking aboot. About 101% off base speculation on your part.
It was a little claim. Like the 1000s of little claims they process every day.
And there’s no details. This all sounds hinky since $17k wouldn’t replace the crane under that truck. Not even close.Lol!! I'm trying too hard?! My post was meant to be speculative humor that you took way, way, too seriously :)
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otrfun
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02/21/23 07:59pm |
Truck Campers
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RE: WFCO WF8955PEC
. . . if I wanted 200 amps lithium would ya buy a 200 or 2 separate 100s ?It's important to know that 100ah and 100a are two very different ratings.
Following assumes your system will be operating on 12vdc.
If you purchase two 100ah 12v lifepo4 batteries, make sure they can *each* produce 100a of continuous current. Wired in parallel, this will enable you to produce 200a of total continuous current, enough to power a microwave.
A similar caution applies to a single 200ah lifepo4 battery. Make sure it's capable of producing 200a of continuous current. Some 200ah lifepo4 batteries are only capable of 100a of continuous current. 100a of continuous current is not enough to power a microwave---200a is.
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otrfun
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02/20/23 09:24am |
Tech Issues
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RE: A happy ending?
Insurance company pays for driver-owner’s irresponsible malfeasance, then he unloads his truck on some poor unwary, meanwhile others wonder why their rates keep climbing…Why complain, isn’t this just the American way?? (LOL!)
3 tonsHaving recently dealt with an insurance claim, it seems that the insurance companies do not care about the high cost of coverage. Higher expenses just mean they can justify higher premiums . . . .I sometimes wonder if GEICO's approval of Pavel's claim (snapped frame on his Ram 3500 dually) was a one-time marketing decision. With his photos going viral, they knew approving this particular claim would generate free, positive publicity for GEICO---more than enough to make up for the $17k payout. GEICO knows they're under no obligation to approve any future claims of this type in the future.
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otrfun
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02/20/23 08:18am |
Truck Campers
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RE: A happy ending?
TCA did an outstanding job of explaining what I feel is the primary reason this guy's frame failed---improper COG. If the COG had been located directly over the rear axle, and not a number of feet behind, this particular failure would have never occurred---even overloaded as he was.
If the owner of this truck would have taken the time to visit a scale (unloaded and loaded), yes, he would have discovered his truck was overloaded. However, he would have also discovered his front-axle was being off-loaded hundreds and hundreds of pounds---indicating a COG far behind the rear axle.
IMO, it's not a simple case of calculating GVWR and payload and calling it safe. *Where* you place the payload (COG) is a critical consideration, too.
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otrfun
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02/16/23 10:09am |
Truck Campers
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