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03-02-2021, 08:29 PM #11
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Is there any reason to expect that the prismatic cell will have significantly less longevity than the cylindrical cell that Battle Born is using? Both cells are produced in China AFAIK. FWIW, Battle Born advertises 3000-5000 cycles, which is comparable with, for example, SOK, who advertises 3000-8000 cycles for their prismatic cells.
Last edited by rootusrootus; 03-02-2021 at 08:31 PM.
Current: 2021 Transcend 261BH, 2019 Ford F250 SRW SWB CC 6.2 - Picture
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03-02-2021, 08:39 PM #12
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Yeah I'm not sure what size system I need. I need to do an energy survey. I'm going to assume that it's not practical to run AC units off of batteries, so I'll leave the genset for that. Other than that, we're talking the refrigerator, microwave, and other small appliances, as well as tv's, routers, laptops. I watched the video and I understand you can set the BMS to discharge and recharge within certain parameters to protect the batteries.
This certainly sounds like the way to go for massive cost savings. We plan on going to Alaska next summer so I have some time to spec out and build the system. I've got a LOT of learning to do. Thank God for websites and YouTube!
2017 Ford F450 - our kids call her "Big Red"
2018 Grand Design Reflection 28bh
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03-02-2021, 08:43 PM #13
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Yeah, the front compartment seems to be the best place for the batteries. The main buss bar is up there. And that space isn't being used for anything else. I plan on having a metal plate to act as a reinforcement for the compartment. Then I can either buy or build a battery box. So long as the trailer can take the weight, I'm not too worried about increasing my tongue weight.
2017 Ford F450 - our kids call her "Big Red"
2018 Grand Design Reflection 28bh
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03-03-2021, 05:47 AM #14
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Unfortunately, you are correct, many Chinese batteries have been marketed with a lot of "Hype" and exaggerated claims about their storage capacity, for example: the best 18650 batteries from Panasonic, LG Chem and Samsung were capable of ~ 3,200 milliamp hours (mAh) of storage however there were dozens of Chinese manufactured 18650 cells that claimed 9,000 mAh of storage capacity.
Knowing the above history, I can tell you that I would be comfortable with buying these new 280 amp hour cells from China. First, because the LiFePo4 chemistry is very safe and stable. Secondly, the LiFePo4 chemistry is very long lasting, especially if you only use the middle 80% of the battery's charge range.
If you viewed the video I linked to in an above post, you may have noticed the presenter mention that there are "A" cells and "B" cells, basically that refers to "First Quality" cells and factory "Seconds". While you want the "A" cells the "B" cells are probably going to perform adequately for an RV installation due to the low draw nature of the 12v electrical system in our coaches. There are ways to avoid receiving the "B" cells and you should definitely get the "A" cells, especially if you are going to be using an Inverter that provides more than 1,000 watts of AC power. First, you want to try to order from the supplier mentioned in any of the videos that received "A" Cells, next, you want to inspect your cells to ensure they do not have any defects and that the "QR" code is intact (manufacturers obliterate the QR codes on factory seconds). Secondly, if you are going to buy more than four cells, I would recommend buying a battery tester that would let you charge each cell and test the amp hours to ensure you are getting exactly what you paid for.
I would also recommend that you oversize your battery bank so that you are not running "Close to Empty" on a regular basis, that way, you will not be constantly worried about running out of power in the middle of a cold night when the furnace quits working (trust me, that is NOT Fun). From experience, I can tell you that it is pure joy to have plenty of battery storage on board the RV and that a large Inverter (3,000 Watts) really makes life aboard the RV very convenient, for example: we can stop for lunch and have hot meals because the Microwave is always available. Besides that, my wife loves having electricity constantly available.
If the above hasn't allayed your fears, let me try to explain how simple the project would be to put together...
Imagine that you had 4 12v batteries that you wanted to install in your coach, you line all 4 in front of you with the Negative post on your left and the Positive post on your right. Now if you want to use these batteries in a 12v configuration you would simply run a cable from one Neg post to the next Neg post to the next Neg post, you do the same with the Pos posts. At the end you will have 12 volts to power your coach, this is called a parallel string. Now imagine that you take your 4 batteries and place them side by side, still with the Neg posts on the left and the Pos post on the right. In this example, you are going to place a cable on the left most battery's Pos post and attach the other end to the Neg post on the battery right next to it, you will then attach a cable to that battery's Pos post and attach the other end to the Neg post of the next battery, at the end, if you measure the voltage between the furthest left Neg post and the furthest right Pos post you will get 48 volts instead of the 12 volts you had in the previous example. This is called a Series string, in a series string the voltages are additive, whereas in a parallel string the voltages remain the same as all the batteries in the string. Now with the LiFePo4 batteries the voltages are 3 volts instead of 12 volts and by wiring 4 batteries together in "Series" that is how you get 12 volts for your coach. The only additional wiring you need to do is to wire the Battery Management System (BMS) to your 4 batteries.
Part of the reason this 280 Ah battery project is so tempting is the simplicity of the project, you could easily build this project in an hour if you understand the wiring process. If you are building a larger battery bank you might need two hours but the project itself is pretty easy.
Let me know if you would now be tempted to tackle this project.
PS: you will need to install these batteries in a structure that keeps them in compression.
PPS: The LiFePo4 battery chemistry I am referring to stands for Lithium (Li) Iron (Fe) Phosphate (Po4) batteries, the same chemistry as used in the Battle Born batteries.Last edited by SolarPoweredRV; 03-03-2021 at 06:28 AM.
David and Peggy
2019 Ford F350 Lariat, 6.7L Diesel, Dually, Long Bed
Running with 20k Reese Goosebox (Love It) and Ford Factory "Puck" system.
Stopping with 8,000 lb Disc Brakes and Titan Hydraulic over Electric Brakes system.
Powering all this fun with 1200 Watts of Solar, two Tesla, Model S, battery modules, 24 volt Victron Inverter.
2018 Solitude 310 GK
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03-03-2021, 06:01 AM #15
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Don't forget to include your furnace in your energy calculations. The furnace is the most power hungry (and inefficient) appliance you have in your coach. As a matter of fact, that is the main reason we purchased a second Tesla battery module, one Tesla battery just wasn't quite enough to give us the length of energy storage we wanted.
To give you a reference point, our system is equivalent to 10 Battle Born batteries, of which we only use the middle 80%. For safety and longevity reasons we reserve the top and bottom 10% of our battery giving us approximately 800 amp hours of usable energy storage (8 Battle Born battery equivalent).David and Peggy
2019 Ford F350 Lariat, 6.7L Diesel, Dually, Long Bed
Running with 20k Reese Goosebox (Love It) and Ford Factory "Puck" system.
Stopping with 8,000 lb Disc Brakes and Titan Hydraulic over Electric Brakes system.
Powering all this fun with 1200 Watts of Solar, two Tesla, Model S, battery modules, 24 volt Victron Inverter.
2018 Solitude 310 GK
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03-03-2021, 06:12 AM #16
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No reason to expect any less longevity, especially if you size your battery bank to reserve the top and bottom 10% of charge and only use the middle 80% of the battery.
If you think about it, 3,000 cycles is almost 10 years of use based on a full charge/discharge cycle every day and 8,000 cycles is 21+ years. These batteries should last even longer if you only use the middle 80% of the battery.
When you look at longevity like this, and the low price, these batteries are an insanely good value.David and Peggy
2019 Ford F350 Lariat, 6.7L Diesel, Dually, Long Bed
Running with 20k Reese Goosebox (Love It) and Ford Factory "Puck" system.
Stopping with 8,000 lb Disc Brakes and Titan Hydraulic over Electric Brakes system.
Powering all this fun with 1200 Watts of Solar, two Tesla, Model S, battery modules, 24 volt Victron Inverter.
2018 Solitude 310 GK
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03-03-2021, 06:35 AM #17
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Thanks. Good tips in your post about avoiding seconds and getting the best cells. Some of them require having the battery for testing and an honest dealer who would easily replace underperforming cells.
In your series/parallel paragraph I guess you're deliberately simplifying for illustration purposes? You likely know that connecting the batteries in that "illustrative" way is not the best for the batteries long-term. The following link describes ways of interconnecting multiple batteries to extend their life.
http://www.smartgauge.co.uk/batt_con.html
Is this information wrong or superfluous for batteries with onboard battery management systems?
Thanks again.Mark - 2018 Solitude 310GK - 2017 F-350 diesel SRW short box - Pullrite Superglide hitch
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03-03-2021, 10:12 AM #18
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Yes, the Series/Parallel description was simplified for educational purposes, however the paper you linked to would be more pertinent in a high amperage draw situation and would only apply to the Parallel portion of the above discussion. Additionally, I am not sure that wiring LiFePo4 batteries in the suggested sequences would make much difference to the batteries because of their high charge/discharge capability. For example: if you built a 4s/4p battery bank (see below) and you wired the Parallel portion as I described you might draw extra energy from one of the batteries (group of 4), however, once the high amp draw stopped the battery bank would quickly rebalance itself because the LiFePo4 chemistry is so quick to charge up.
If you are going to have a large battery bank, I would suggest your Parallel wiring could be done as "Method 2" in the above linked document to draw current more evenly from all batteries in your Parallel string. With that said "Method" 3 or 4 would be perfectly fine as well.
Even if you choose "Method 1" from the above linked paper the LiFePo4 batteries would probably not be effected because of their high charge/discharge capability.
Note: 4S/4P refers to: 4 batteries in series (4s) to make a 12v battery, and then 4 groups of 4 tied together (4P) to give you a larger 12v battery bank.David and Peggy
2019 Ford F350 Lariat, 6.7L Diesel, Dually, Long Bed
Running with 20k Reese Goosebox (Love It) and Ford Factory "Puck" system.
Stopping with 8,000 lb Disc Brakes and Titan Hydraulic over Electric Brakes system.
Powering all this fun with 1200 Watts of Solar, two Tesla, Model S, battery modules, 24 volt Victron Inverter.
2018 Solitude 310 GK
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03-03-2021, 11:16 AM #19
When putting batteries in parallel, I would definitely recommend "Method 3" which is essentially, run each battery to a busbar and then connect loads and chargers to that busbar. This allows you to keep the cable lengths between each battery and the busbar even removing the concern about imbalance across the bank. Victron Lynx is an excellent product to achieve this as it includes but the + and - busbars with high quality mounting positions and is easily expanded horizontally. This is what I did in my own system. I have 2 batteries currently but will be adding a 3rd which will be removable to put in a truck camper as needed.
2019 GMC Sierra 3500HD Denali Diesel DRW (Crew Cab | 8 Ft bed | OEM Puck System | Curt Gooseneck Ball for OEM Puck | Timbrens on rear axle)
2019 Grand Design Solitude S-Class 3740BH-R Fifth Wheel (Onan 5500W LP Generator | MORryde CRE3000 and HD Shackles/Wet Bolts | 3x MORryde Cross Members | 8k Axles and Disc Brakes | Sailun S637 ST | Reese GooseBox 20k 2nd Gen | Splendide Stackable Washer and Dryer)
Full Suite of Victron Energy Products (2x 5k 24v Quattro Inverter/Charger | 2x 25.6/200 LFP Smart LiFePO4 Batteries | 2880w of Solar Panels across 4x MPPTs | Cerbo GX)
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03-03-2021, 12:10 PM #20
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