StirCrazy
Kamloops, BC, Canada
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Joined: 07/16/2003
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Itinerant1 wrote:StirCrazy wrote:Itinerant1 wrote:Just curious if the batteries are working with the predetermined settings in the sealed box why would you want to experiment with them?
easy cycle life. if I can change the top and bottom from 0 to 100% to 10 to 90% that can take your average LfP from 3500 cycles to 4500 to 5000. then if you operate in the top 3rd of that you can go even higher. If I knew I could get into a battery like a chins I may have bought them instead of making my own just to be lazy, but I use the settings in my Bluetooth quite a bit. I have 3 profiles on my phone for setting the BMS, I have a storage routine where the BMS will only charge the cells to 65% of the capacity then won't recharge until they drop below 30% as well my cold temp cut off is bumped up to 3C to be safe. I have a "getting ready to go camping" setting where it sets the bottom at 10%, puts the cold temp cut off back to 1C and charges to 100%. then I have a "camping" setup where the only difference is I lower the top to 90%.
I can limit the battery as I have a 10-day capacity without the solar and unlimited time with the solar, so I decided to make the battery last a bit longer and sacrifice about 2 days' worth of capacity. The batteries are top balanced and topped right up whenever I leave the house on a camping trip.
So basically, cycle life, and the ability to be over cautious on some of your safety settings is the reason.
Ok, thanks for the info.
Seems like alot of work but then you have different needs and colder weather.
As far as cycle life why worry about do you really think your going to use it up? I bet more folks will kill their batteries hen pecking them.
Right now I've done 2,502 days (boondocking) of 2,686 days since install. I'm somewhere over 1,000 full cycles and that's 7 years 4 months. A seasonal camper the batteries should last along time.
I guess living off mine fulltime with solar one set of settings. Charge to 14.1v (my 100% SOC), float 13.6, if they get full great and if not tomorrows another day solar might fill the tank. Still use whatever in the 5th wheel including the air conditioner.
ya I figure I will get about 20 years out of mine at the rated 3500 cycles, the problem is, and this is still and unknown, will the batteries age out before the cycle life is up in my situation. so, I am wondering if how we use them can increase the aging out time on them also. some people speculate 10 years of use they will start to age.. personally, I think that is to young for them to age out so this is a long-term experiment, conservative operating range, shallow discharge.10 to 15% in normal situations). the only reason I can do this is because I got 280AH of capacity for about 700US (after conversion) I am also still young if I can make them last 30 to 35 years that will work out perfect for me ![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/wink.gif "wink")
2014 F350 6.7 Platinum
2016 Cougar 330RBK
1991 Slumberqueen WS100
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S Davis
Western WA
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Joined: 08/11/2005
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At 3500 cycles they should still have 80% of their rated capacity.
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StirCrazy
Kamloops, BC, Canada
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Joined: 07/16/2003
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S Davis wrote:At 3500 cycles they should still have 80% of their rated capacity.
yup that's how LiFePo4 are rated. but let's take a look at that number. I have a 280 AH battery of which I only make available 80% of the available capacity so that like saying I have a 224AH battery. If I do something to lower the cycle life or just hit that point then my 280AH battery becomes a 224AH battery and if I operate it at 80% capacity to keep it going as long as I have then I effectively have a 179AH battery. which for me means that I have lost 2 days of camping if the solar is down before I need a recharge. My point is if you are able to run at 80% capacity off the start and shallow discharge why wouldn't you try to post phone that 80% cycle life marker.
I understand for some people it isn't an option as they have to run their AC and such and its expensive just to get enough capacity both in solar and batteries for that, but while if I camped in my driveway, I would be one of those people also as I am in the hottest city in Canada for summer temperatures. but I can also drive an hour and get out of the valley and be at much higher elevations where it might be a little warm during the day but cools off dramatically for sleeping which means I don't need the high capacity some do.
now in my 5th wheel I would use more power and I am setting that up with a lot more AH and a lot more solar than the camper.. I have no 120power in the camper and my biggest worry is the furnace as I do a lot of early spring and lait fall higher elevation camping and that furnace will suck up to 36AH overnight, so it is set up to be able to do 7 to 10 days of camping if the solar is not producing so generally it is a shall discharge setup with and emergency reserve capacity.. so, a perfect set up to test how much you can increase cycle life.
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3 tons
NV.
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Agree, LFP’s have proven to be quite tolerant to a wide variety of discharge and charge strategies, and single voltage charging is quite simple all the while skipping the nail biting frequency for a full charge…Kinda funny for those who recall all the fact-less boogieman fictions that were being actively pushed in the not so distant past - lol…
3 tons
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Itinerant1
Itinerant
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Joined: 05/23/2017
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3 tons wrote:Agree, LFP’s have proven to be quite tolerant to a wide variety of discharge and charge strategies, and single voltage charging is quite simple all the while skipping the nail biting frequency for a full charge…Kinda funny for those who recall all the fact-less boogieman fictions that were being actively pushed in the not so distant past - lol…
3 tons
I can think back when they were coming on the scene and it was a novelty with a lot of nay sayers with wild end of the world predictions because they didn't understand them, plus confusing the chemistries up. I'm glad I took an early leap and seemed to get lucky with my charging regime which seems to be working so far.
Right now just about packed up for a dump station run and relocation to another boondock location. SOC after breakfast microwave, coffeemaker was 53%, suns contributing some now to charging, turned the air conditioner on to cool the rig down before the move. SOC 55% inverting 12.7v -129a. Amazing after 7 plus years that the 500ah bank is still supplying good power in all conditions and DODs.
With my control displays at easy reach or viewing bluetooth personally would be of no benefit. The system now is something just runs in the background quietly.
12v 500ah, 20 cells_ 4s5p (GBS LFMP battery system). 8 CTI 160 watt panels (1,280 watts)2s4p,Panels mounted flat. Magnum PT100 SCC, Magnum 3012 hybrid inverter, ME-ARC 50. Installed 4/2016 been on 24/7/365, daily 35-45% DOD 2,500+ partial cycles.
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3 tons
NV.
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“With my control displays at easy reach or viewing bluetooth personally would be of no benefit. The system now is something just runs in the background quietly.”
Very well said Sir, fact is I couldn’t agree more ![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/smile.gif "smile")
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StirCrazy
Kamloops, BC, Canada
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Joined: 07/16/2003
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Itinerant1 wrote:
With my control displays at easy reach or viewing bluetooth personally would be of no benefit. The system now is something just runs in the background quietly.
yup and I believe that is what I said at the beginning of the post also., I don't have a Victron system though just an amp hour counter. the cheap 40 buck version of Victron's 150 buck one. works great.
This part of the discussion was an after the fact of why someone would want Bluetooth functionality and that's how I use it between my solar controller and my battery as they both have Bluetooth.
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