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RE: Voltage Drop - NOT Park Problem
I'm done here. Thanks for all the reasonable suggestions. If I ever resolve it I'll come back and update this post.
So was the most of the voltage drop at one spot or small drops at multiple spots? Did you check each connection with your meter, it’s not magic it has to be coming from somewhere. Have you checked the start capacitor on the A/C to make sure it’s not the issue/ what are the rated starting amps and what are they actually. Is the voltage drop at the breaker panel the same or close to what it is at the A/C unit?
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S Davis
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01/08/23 01:02pm |
Tech Issues
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RE: In bed fuel transfer tank question
I have a 52 gallon aluminum, it does form condensation(western WA) so I would plan either don’t draw off the bottom and have a drain or have some kind of water separator. I went off the bottom into a water separator and then to a 30gph pump which is plumbed into the trucks filler neck. I have the pump hooked up to a mechanical 30 minute timer, one twist and about 15 gallons transfers.
https://i.imgur.com/tNFNfH2l.jpg
https://i.imgur.com/dWzIJpKl.jpg
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S Davis
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01/08/23 11:34am |
Tow Vehicles
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RE: Filtering Our Diesel Storage Tanks For on Road Use
A lot of nice places to see, here is Mount Baker from the south.
https://i.imgur.com/MLGlA9yl.jpg
https://i.imgur.com/76M3Gkkl.jpg
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S Davis
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01/04/23 12:48pm |
Tow Vehicles
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RE: Filtering Our Diesel Storage Tanks For on Road Use
If your tank is Metal I would be worried about the extra moisture, I have a 52 gallon aluminum and it forms condensation. I went with a dedicated moisture filter, and will get water out the drain.
https://i.imgur.com/Ss7uSLbl.jpg
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S Davis
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12/30/22 06:19pm |
Tow Vehicles
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RE: Lithium battery box temps
This is my heating for my two 280ah LifeP04 batteries. I use a 25 watt silicone heat pad sandwiched between aluminum plate and blow air across it, kept them at 50f at 8f outdoor. They are installed in the rear seat area of my crew cab.
https://i.imgur.com/vR3FsDQl.jpg
https://i.imgur.com/x6BSdKel.jpg
https://i.imgur.com/uTotJ1Yl.jpg
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S Davis
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12/30/22 10:38am |
Truck Campers
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RE: DIY Li Battery Heater...A REAL TEST!
DIY Battery Heaters...A REAL TEST!...got down to 7F degrees last night. At 7am the battery compartment is at 35 degrees. Controller is set to turn on at 35F and off at 38F........The batteries are at 90% on the monitor.....Working GREAT!... http://rvbprecision.com/rv-projects/lithium-battery-heating-project.html
http://rvbprecision.com/rv-projects/lithium-battery-heating-project.html
It doesn’t take much to keep them warm, I set mine at 50f with 25 watt silicon heat pads. We got down to 8 degrees this week and no problem keeping my two 280 ah LifeP04 batteries warm. It’s nice hoping into the truck at 8 degrees and having a heated throw on your seat.
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S Davis
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12/24/22 11:59am |
Tech Issues
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RE: Lithium for dummies: need advice in simple terms
. . . What I don't know is if below freezing will affect the battery life while discharging or storing.Specs vary from manufacturer to manufacturer, but generally speaking, maximum recommended discharge current tapers downward as temps drop below 32f or so. Probably wouldn't want to do more than a .10c - .15c discharge at temps below, say, -10c (14f).
Long-term storage recommendations are not too stringent. If you follow the temp recommendations for charging (typically 0-40c; 32-104f) that should be acceptable. If you want the absolute best for your cells, strive for 25c (77f) and 30-50% SOC.the specs for the new cells I ordered are pretty good that way, 0.5C discharge down to -30C short term storage of a month -40C/F long term storage -25C and charger from -5C to +60C. but it totaly does depend on the manufacture and for premades, they tend to add a little more of a buffer so they have less warenty clames they have to pay.Very impressive. As far as advertised specs, it can work both ways. Make them conservative so they can reduce warranty claims, or make it look like their cells walk on water to sell more cells/batteries. Me, I tend to give the research and testing produced by independent labs the most creedence.
these are the new K cells from EVE and the specs are from eve's testing sheets not a salesman ;) . now am I going to set them to charge ar -5C, naa I'll keep it at +1 as my batteries are inside the living space so will never get that cold anyways, I may test the cold discharge though... well then again naa, I aint going camping at -30C haha, but the thing of interest to me was you can short term store much colder than long term (short term they describe as 30 days or less) and the fact that they seam to be a significantly more robust than the normal 280AH cells rated at 5000 cycles (100% to 0%) instead of 3500and I realy like the new double tapped termanals on them two bolts for power path instead of one skinny post.
Steve
They are not much more robust, they changed the testing specifications. The older LF280N that I have are rated at double the amp draw, 1c for 3500 cycles with a compression fixture. The new LF280K are rated at half that at .5c for 6000 cycles with a compression fixture.
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S Davis
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12/13/22 11:24am |
Tech Issues
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RE: Lithium for dummies: need advice in simple terms
Mordecai, what do you use to monitor whether you are short amps? (Different from a short circus, I think.). ;)
No, seriously, which device will give you an accurate picture of the remaining battery capacity? Using a cheap multimeter, I often check the voltage on my lead acid batteries, on the theory that any reading below 12.1 means that I've got a state of charge less than 50%.
But with lithium batteries, the voltage does not drop, I think. The battery goes from "full" to "dead," if I remember correctly.
Full charge is about 13.4 volts, at 12 volts you are at about 10% charge with LifeP04. Voltage does drop with state of charge just not as much as lead acid.
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S Davis
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12/08/22 07:11pm |
Tech Issues
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RE: Lithium for dummies: need advice in simple terms
It really doesn’t take a lot to keep the cells warm, I use a 3”x3” 12 volt 25 watt silicon heat pad on each battery and they have worked perfectly down to 8f in back seat area of my crew cab. I have them set about 50 degrees, with two 280ah batteries I can spare the ah to run them.
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S Davis
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12/08/22 11:07am |
Tech Issues
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RE: Lithium for dummies: need advice in simple terms
S Davis.
Some take away's about LiFePo4 batteries
"There is more to calendar life and how quickly a LiFePO4 battery will age: State-Of-Charge has something to do with it as well. While high temperatures are bad, these batteries really, really do not like to sit at 0% SOC and very high temperatures! Also bad, though not quite as bad as 0% SOC, is for them to sit at 100% SOC and high temperatures. Very low temperatures have less of an effect. As we discussed, you cannot (and the BMS will not let you) charge LFP batteries below freezing. As it turns out, discharging them below freezing, while possible, does have an accelerated effect on aging as well. Nowhere near as bad as letting your battery sit at a high temperature, but if you are going to subject your battery to freezing temperatures it is better to do so while it is neither charging nor discharging, and with some gas in the tank (though not a full tank). In a more general sense, it is better to put away these batteries at around 50% – 60% SOC if they need longer-term storage.
Melted battery
If you really want to know, what happens when a lithium-ion battery gets charged below freezing is that metallic lithium is deposited on the negative (carbon) electrode. Not in a nice way either, it grows in sharp, needle-like structures, that eventually puncture the membrane and short out the battery (leading to a spectacular Rapid Unscheduled Disassembly Event as NASA calls it, involving smoke, extreme heat, and quite possibly flames as well). Lucky for us, this is something the BMS prevents from happening."
So if you have solar--turn it off during storage. I don't like that.
This is the summary from the article:
"To sum up, for long and happy LFP battery life, in order of importance, you should be mindful of the following:
Keep the battery temperature under 45 C (113 f) (under 30C if possible (86 f)) – This is by far the most important!
Keep charge and discharge currents under 0.5C (0.2C preferred)
Keep battery temperature above 0 C (32 f) when discharging if possible – This, and everything below, is nowhere near as important as the first two
Do not cycle below 10% – 15% SOC unless you really need to
Do not float the battery at 100% SOC if possible
Do not charge to 100% SOC if you do not need it"
The above are from https://www.solacity.com/how-to-keep-lifepo4-lithium-ion-batteries-happy/
another good page on care and feeding:
https://dakotalithium.com/2021/09/22/how-to-charge-dakota-lithium-and-lifepo4-batteries/
Ok so you are getting it from a company trying to sell batteries instead of the manufacturer of the batteries, their recommendation has more to do with warranty than affecting cycle life.
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S Davis
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12/07/22 08:45pm |
Tech Issues
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RE: Lithium for dummies: need advice in simple terms
S Davis,
I got the figures from the wobbly wide web. If I were going Li I'd go 40% to 85%. I never will due to cold.
Your document is too blurry for me to read.
Ok well I have read just about every spec sheet for the currently available LifeP04 cells and have never seen that in any of them, all their definitions of a battery cycle are from full charge to 2.5 volt cutoff at the stated amount of cycles.
Do you have any spec sheets that say that? If not you are giving out false info. You can use 100% of the stated capacity and still get the rated cycles according to the manufacturers of the cells.
I will try and get a better screen shot, this might be a little better.
https://i.imgur.com/tPVpRbql.png
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S Davis
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12/07/22 02:44pm |
Tech Issues
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RE: Lithium for dummies: need advice in simple terms
profundant,
20% to 85% for Li, so the 100 amp-hour has 75 amp-hours that are usable.
charge them to 100% once every 30 days to reset the battery management system.
Use a dc to DC charger for alternator protection, if planning to charge from the engine.
I can't use LI where I live. Too cold for them. For those that can avoid cold LiFeP04 are the cat's meow.
I would go for SiO2 myself.
Where do yo get the 20% to 85% figures, the EVE prismatic cell cycle rating is full charge to cut off at 2.5 volts @ 1.0C for 3500 cycles.
https://i.imgur.com/gOIyL1Wl.jpg
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S Davis
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12/07/22 10:59am |
Tech Issues
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RE: fell victim to the scam
I purchased 28 EVE cells from Docan Power in two purchases. The cells are excellent, but they are the LF280N which is the previous model. There have been reports of bloated cells and slightly low capacity with the newer LF280K.
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S Davis
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12/02/22 10:31am |
Tech Issues
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RE: Lithium batteries
I only plan on 350 amps max so two 250amp BMS should cover it.
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S Davis
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12/01/22 12:00pm |
Tech Issues
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RE: Lithium batteries
S Davis,
So what are the components in your battery bank? Which battery management system?
Here is most of it I am adding a victron multiplus or a outback 3000 watt inverter.
600amp buss bars
4/0 DLO cable rated at 405amps from the 600a buss bar to battery switch
3/0 DLO cable from the batteries to the negative 600amp buss bar
600 amp dual bank battery switch/one on, both on or both off
3/0 DLO cable rated at 350amps from switch to each 280ah battery
300amp MBRP fuses on the positive of each battery
Battery buss bars rated at 300amps
Daly 250amp 4-S BMS
There is also a heating system on each battery with 25 watt silicone heat pads and fans, I keep them about 50 degrees F.
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S Davis
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12/01/22 10:51am |
Tech Issues
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RE: Lithium batteries
“I could just take the two 4s BMS off and use a 100amp 8s BMS that turns all 8 cells into one battery instead of two in parrelell.”
Except you just made a 24 volt battery with a 8-S BMS. Eight cells in series makes 25.6 volts. To stay at 12 volts and up the ah you would have to use a 4-S BMS and use parallel sets of cells. The draw back is not being able to monitor each cell in the battery.
true, you would be monitering groups of cells, but if you get quality cells that are matched, thats not an issue.
I still recomend building seperat batteries unless you want to go to a higher capacity and use a stepdown. but in my case I would do another 310AH battery and have two of them. so when I am using my camper I would just use one as thats 10 days camping with the furnace running 24/7, but for my 5th wheel I could have two in there and just move one back and forth between the 5th and the camper. one will give me more usable capacity than I have with my four 6V batteries so it will be fine when I am using the camper, but when I am going for a longer dry camping backwoods with the 5th wheel I can put the second in and double my capacity. being only 48lbs its not a big deal either.
That is what I did, I have almost 2000ah in seven 12 volt 280ah batteries. I have two in my work truck with a few spares.
https://i.imgur.com/vmZmWvDl.jpg
I like thoes diaganal bus bars, where did you buy your cells from?
Steve
I cut and drilled them, it can be ordered in any amp rating. I got it at Galco, it is called Eri flex. The cells are EVE LF280N I purchased from Docan Power, they ran about $150.00 per cell delivered.
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S Davis
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12/01/22 10:32am |
Tech Issues
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RE: Lithium batteries
“I could just take the two 4s BMS off and use a 100amp 8s BMS that turns all 8 cells into one battery instead of two in parrelell.”
Except you just made a 24 volt battery with a 8-S BMS. Eight cells in series makes 25.6 volts. To stay at 12 volts and up the ah you would have to use a 4-S BMS and use parallel sets of cells. The draw back is not being able to monitor each cell in the battery.
true, you would be monitering groups of cells, but if you get quality cells that are matched, thats not an issue.
I still recomend building seperat batteries unless you want to go to a higher capacity and use a stepdown. but in my case I would do another 310AH battery and have two of them. so when I am using my camper I would just use one as thats 10 days camping with the furnace running 24/7, but for my 5th wheel I could have two in there and just move one back and forth between the 5th and the camper. one will give me more usable capacity than I have with my four 6V batteries so it will be fine when I am using the camper, but when I am going for a longer dry camping backwoods with the 5th wheel I can put the second in and double my capacity. being only 48lbs its not a big deal either.
That is what I did, I have almost 2000ah in seven 12 volt 280ah batteries. I have two in my work truck with a few spares.
https://i.imgur.com/vmZmWvDl.jpg
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S Davis
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12/01/22 12:44am |
Tech Issues
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RE: Lithium batteries
“I could just take the two 4s BMS off and use a 100amp 8s BMS that turns all 8 cells into one battery instead of two in parrelell.”
Except you just made a 24 volt battery with a 8-S BMS. Eight cells in series makes 25.6 volts. To stay at 12 volts and up the ah you would have to use a 4-S BMS and use parallel sets of cells. The draw back is not being able to monitor each cell in the battery.
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S Davis
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11/29/22 03:01pm |
Tech Issues
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RE: DC to DC charger
That is not true on newer GM HD trucks, my 2019 Chevy 2500HD sits above 14 volts, when changing my batteries it will ramp up to just above 15 volts @ 50amps.
According to the above statement I should have a smart alternator, but I have yet to see this mysterious lowering of voltage a few people on here keep stating.
Check the voltage at the starting battery immediately after starting and at the house battery.
Drive for 10-15 minutes and, with the engine still running, check those voltages again.
I have voltage meters, they stay constant above 14v and if the LifeP04 are charging it’s highe.
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S Davis
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11/28/22 10:24pm |
Truck Campers
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RE: DC to DC charger
... on newer GM HD trucks, my 2019 Chevy 2500HD sits above 14 volts, when changing my batteries it will ramp up to just above 15 volts @ 50amps.
15+ volts is all the more reason for a DC to DC Charger. I don't think Lithiums will agree with that high of a charge voltage.
I am using a 50amp DC to DC charger.
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S Davis
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11/28/22 10:17pm |
Truck Campers
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