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Date Posted |
Forum
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RE: For BFL13 et al... FLA vs AGM vs Li vs heated Li
Steve,
The high temperature information came from a seller, not a maker. It seems quite counter intuitive to me for a seller to post such negative information.
I decided to look for a more scholarly article. I searched for 'temperature at which damages starts on LiFePo4' and this is what I found.
"The LIBs, however, are still facing barriers that limit their application space , . One of the major limitations is the impact of temperature to the proper operation of the LIBs. Generally, the acceptable temperature region for LIBs is -20 °C ~ 60 °C . Pesaran et al. showed that the optimal temperature range for LIBs is 15 °C–35 °C. Once the temperature is out of these comfortable regions, LIBs will degrade fast with increased risk of facing safety problems that include fire and explosion."
For my American friends 15 C to 35 C = 59 F to 95 F, and -20 c to 60 c is -4 F to 140 F.
There is no way I want any type of large secondary battery in my living space.
https://www.sciencedirect.com/science/article/pii/S1002007118307536
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pianotuna
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03/02/21 07:46am |
Tech Issues
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RE: Resuming Rving... ideas dealing with Covid.
Have the vaccination. Then consider the viral load in the locations you wish to visit. Plan the route accordingly.
There is a clear case that high population centers (cities) have more transmission than lower population.
Take precautions such as using disposable gloves when buying fuel.
If you stay in campgrounds, sanitize as much as possible.
If possible, have food delivered to your RV rather than going into stores.
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pianotuna
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03/01/21 11:19am |
Family Camping
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RE: Renogy DC-DC Charger UPDATE 2 Test
BFL13,
You added a switch. Which wire did you switch??? lol!
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pianotuna
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03/01/21 10:07am |
Tech Issues
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RE: New Cooper tires behavior
Tire pressure too high may have the same effect, especially on the front wheels.
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pianotuna
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03/01/21 09:46am |
Truck Campers
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RE: Renogy DC-DC Charger UPDATE 2 Test
IMO sense wire is one of those feed-back things. Anyway, see the manual and all will be revealed! :) Yours in the Ford MH will be different from how I did it.
Mine will be different than almost all other motorhomes, because I went for twin charging paths. One is OEM modified with a 50 amp-circuit breaker (I kept blowing fuses), and the other is direct from the chassis battery, with a 50 amp circuit breaker. I also added manual switching to each isolation solenoid and upgraded the amperage so that burned contacts are not an issue.
When I had flooded batteries I did "see" as much as 70 amps of charge. When I moved to telecom jars I see little or no charging--in fact the power flow is to the chassis. I.E. almost no alternator charging at all. I did try to correct this by replacing the Chassis battery with an AGM, to no avail.
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pianotuna
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03/01/21 09:34am |
Tech Issues
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RE: Renogy DC-DC Charger UPDATE 2 Test
I think you meant to say to use a DC rated switch with appropriate arc suppression, not arc fault detection?
Bruce
yes.
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pianotuna
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03/01/21 09:29am |
Tech Issues
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RE: Lithium Confusion
All the makers have quirks. For example, Magnum has a huge design fault on their inverter/chargers. The cooling fans are 120 volt. So if you shut down the inverter the cooling stops. (burn, baby, burn was my result). To be fair, they did stand behind the warranty.
There are rumors about Outback, too.
I don't understand why solar charge controller prices have not dropped much at all.
My favorite controller for small systems is Grape. If I do upgrade the solar (after all I purchased in 2005) I might just get 2 or 3 of their MPPT units. It would be cheaper than buying one large capacity controller, and warranty is at the local Home Depot.
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pianotuna
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03/01/21 09:26am |
Tech Issues
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RE: For BFL13 et al... FLA vs AGM vs Li vs heated Li
LiFePo4 can be made to work well. Any battery bank can do that, but for LiFePo4, there are lots of extra hoops to jump through. Such as a way to limit charging from an alternator, a truly compatible converter. There are also high temperature concerns, starting at 86 f and possible low temperature "cut off" depending on the design parameters of the battery management system.
With SiO2 there are few of the above concerns.
Li prices are dropping madly. I would speculate that the DIY crowd are already almost at the point of parity in initial cost for the same number of usable amp-hours in lead acid. I did see an LiFePo4 "roll your own" for $480 using cells with cosmetic blemishes. (Grade B)
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pianotuna
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03/01/21 09:14am |
Tech Issues
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RE: Six-Pac D650 - Truck power hook up and adding solar...
gabemcg,
It is best to have a feed from the controller directly to the battery bank, with a fuse at the battery end.
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pianotuna
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03/01/21 09:00am |
Tech Issues
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RE: Renogy DC-DC Charger UPDATE 2 Test
BFL13,
Ignition wire = sense wire. Is that where you placed the switch?
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pianotuna
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02/28/21 09:16pm |
Tech Issues
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RE: Solar Battery Charge Issue
BFL13,
It sounds as if you would love a blue tooth capable charge controller. They are much easier to set up.
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pianotuna
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02/28/21 09:13pm |
Tech Issues
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RE: Calling on Solar Techies
Glad to hear of the success! Your battery bank will love you now.
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pianotuna
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02/28/21 09:07pm |
Tech Issues
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RE: LiFePO4 - SOK or Renogy.
SiO2 work well with partial charging.
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pianotuna
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02/28/21 09:05pm |
Tech Issues
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RE: Renogy DC-DC Charger UPDATE 2 Test
Got a link?
This would do. https://www.homedepot.com/p/Calterm-Illuminated-12-Volt-DC-20-Amp-Rocker-Switch-Red-40310/303616507
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pianotuna
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02/28/21 09:02pm |
Tech Issues
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RE: Renogy DC-DC Charger UPDATE 2 Test
BFL13,
You mean it is on the voltage sense line? Not the one to the battery bank?
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pianotuna
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02/28/21 08:52pm |
Tech Issues
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RE: Renogy DC-DC Charger UPDATE 2 Test
BFL13,
I hope the switch is DC rated with arc fault protection.
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pianotuna
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02/28/21 04:15pm |
Tech Issues
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RE: For BFL13 et al... FLA vs AGM vs Li vs heated Li
The only graphs I can find say that SiO2 are at about 80% of capacity at -20 c (-4 f), and that LiFePo4 are about the same.
Of course if we drop down another 10 degrees to -30c (-22 f) then SiO2 are at 60% and LiFePo4 there is no graph I can find.
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pianotuna
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02/28/21 11:35am |
Tech Issues
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RE: For BFL13 et al... FLA vs AGM vs Li vs heated Li
Steve,
Where do you see the capacity curve for LiFePo4 vs SiO2? I'd love to see the graph.
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pianotuna
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02/28/21 10:20am |
Tech Issues
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RE: Solar Battery Charge Issue
I am charging strictly by solar. Charge controller is a Renogy Voyager. Absorption phase of charging cycle always runs at 14.7V. Equalization is automatically run by charge controller when necessary. Until recently I was able to achieve float within 3-4 hours. Now it can take 6 to 7 hours to achieve float. Thanks,Ken
It is not physically possible to equalize a 200 amp-hour battery bank with a 100 watt panel. You would need at least 120 watts, with absolutely perfect solar conditions, and perfect tracking of the sun. I suggest bumping up to 200 watts of panels.
I'm not familiar with the Voyager controller. On mine, I have to move a dip switch to allow for equalization (or not), which then allows equalization every 30 days. I added an external switch to my controller to allow me to easily toggle an equalization charge. Sometimes I do that to get a few more amp-hours of harvest.
Does the Voyager do temperature compensated charging?
So I repeat, fully charge the bank. Then do a proper equalization charge most probably using 14.8 volts. You may need to "push" that to 15.3 volts. Finally, check the battery bank with a hygrometer.
You are extremely frugal on your power use. So kudos for that!
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pianotuna
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02/28/21 09:58am |
Tech Issues
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RE: Lithium Confusion
Steve,
You can keep the wire the same size if you go up in voltage. I'd suggest using an 100 amp controller for 1300 watts of solar, so it won't be working "full tilt" all the time (unless the battery bank is 24 volts, too). I find electronic devices tend to last longer when they are not "pushed to the edge" of their capacity.
I generally like the Victron products, but have heard rumors that they are not quite as responsive to questions as they once were.
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pianotuna
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02/28/21 09:52am |
Tech Issues
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