Battery Holder

Discussion in 'Electrical & Radio' started by tgalx3, Dec 9, 2023.

  1. Justin Ragucci

    Justin Ragucci Well-Known Member

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    I have two separate wiring harnesses in the NJ that I have and that runs off of 6s lipos and I have one for the drives and a pump and the other for guns and pump because if one were to go I wouldn’t want to be completely dead at least if I have drive and a pump I can survive if I lose drive at least I have guns a pump and could possibly still do damage and survive and get pushed in.
     
  2. tgalx3

    tgalx3 Well-Known Member

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    I like the idea of splitting the systems up. If the one goes I might survive on the other. I like the idea of putting the guns on one and the drive on another.
     
  3. Kotori87

    Kotori87 Well-Known Member

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    Don't confuse independent electrical systems with redundancy. In engineering and systems theory, redundancy is the intentional duplication of critical components or functions of a system with the goal of increasing reliability of the system, usually in the form of a backup or fail-safe. Whether you lose drive, pump, or radio/firing power, you're still rendered combat-ineffective. I saw a LOT of that when I visited the WWCC last year. I could see some benefit to splitting the pump off from the rest of your system if you've got a large, power-hungry pump that may brown-out the rest of your electrical system, but that can also be fixed with a bigger battery. If you really want proper redundancy, then you need at least two drive motors and two pumps. One electrical bus drives one pump and one drive motor, while the other electrical bus drives the other pump and drive motor. Split your firing solenoids between the two buses. Ensure your ESCs have linear-type BECs instead of switching (S-BEC or uBEC) so they can be connected together without the need to cut the red Power pin. Thus, a total failure of one electrical bus will have no adverse effects on your radio power. Alternatively, you could run a third electrical bus specifically for your radio and solenoids, but that's one more component that needs charging before battle and storage-charging after battle.

    In our application, I prefer to have a simple, well-tested, highly reliable system design, rather than the extra complexity of redundant systems. We're not landing multi-billion dollar space rovers on Mars, this isn't nuclear reactor safety, and there are no lives on the line if your system has a problem every once in a while. The worst that can happen is your ship sinks, you go for a swim, and you figure out how to improve your design so that failure mode doesn't happen again. Over five years of testing, my most common failure mode has shifted from catastrophic balsa failure to clogged pump restrictors/suction strainers to cannons that fire 9 out of 10 shots, and has finally settled on recklessly aggressive captain.
     
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  4. bsgkid117

    bsgkid117 Vendor

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    BEC failures are the cause of the overwhelming majority of boat fires. No BEC's, run a receiver battery. This is my philosophy. Curiously, haven't had a boat fire or component smoke since I started doing things this way. The ultimate evolution of this idea is to also pull the servo off of the receiver's bussed 6v power system, and provide it with it's own battery (or main power, in the case of HV servos). A 1300mah 2s lipo runs my receiver all day and takes about 15 minutes to charge. In fact, it runs my boat for an entire regionals when I forget to charge it :whistling:

    No wire harness. Just plug batteries into components. Or, if you need more capacity per component, run a little parallel harness to hook two batteries to a component. This does provide redundancy if your ship is dual shafted, or has multiple pumps, and it prevents one component catching on fire from burning with the entire boat's power supply. Its also easier and simpler than trying to solder up some octopus harness or 12 XT60's to a bus bar. It also provides you with diagnostic information. "Weird, my stb shaft batteries used way more power than my port side. What's going on there? Oh wow, the gear mesh is friction-weld tight. That's a problem." This lets you address the batteries that need addressing between sorties as well.

    My entire Indiana, JB2, and JB3's wire harnesses are these: https://a.co/d/2Q2Ceug

    Your pump is 70% of the power consumption in the boat. If it was me, I would run like @Nomercy suggested and put the 6000mah packs into the pump and the 5000's into the drive motor. As stated, isolated from each other. I'd then run an RX battery, no BEC (its a bismarck, it has room and weight for a tiny cigarette lighter sized battery) and then depending on my mood either split power off the ESC's batteries for the guns or run their own 2200mah pack because I have them already. Nothing should share with the pump batteries.
     
  5. Kevin P.

    Kevin P. Well-Known Member

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    I follow a different school of thought, here's my current approach:
    • Power receiver from a dedicated battery. I use Nimh still because I don't need to worry about discharging it for storage
    • For everything else, power from one shared pool of common batteries all in parallel. Reasons being:
      • This keeps the discharge rate on any single battery low. With 1 or 2 pumps that pull ~40 amps each at 12V, I want to spread that discharge rate over as many batteries as possible, with two main benefits:
        • The system voltage drop will be less than if isolated to 1 or two batteries. Many ESC problems we see are because of voltage drop under load, so this mitigates that issue
        • It should prolong battery life, as the time at high discharge rate tends to have a larger impact on capacity and life than number of charge/discharge cycles
      • It allows pooling of reserve battery capacity, so typically you need fewer total batteries for the same effective buffer
        • Drive power usage is fairly constant, and typically has unnecessary reserve, which I'd rather have available for pumps
      • Most electrical failures now a days are component level (i.e. ESC x stopped working), rather than the boat pulling a Tesla and roasting a bank of batteries
      • If there is a fire, almost all captains will pull the boat off the water rather than waiting for everything else to catch on fire
      • If you forget to plug in a battery, boat will still work (could mask an issue, but pretty rare)
    Downsides of my approach:
    • Any low batteries would be charged with no real current restriction as soon as it's plugged into the bank, so I check voltage to make sure batteries are charged before plugging together
    • Makes swapping some of the batteries mid battle not a great option (because of the above), so one of my current boats I have batteries split for that reason
    For a Bismarck, power distribution should be fairly simple, I would set it up probably with 4x of 3S 6000 mAh (because that's what I have), maybe add a battery if running 2 brushless pumps
     
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  6. tgalx3

    tgalx3 Well-Known Member

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    What batteries are you happy with that are 6000? The company that I was getting batteries from stopped making 6000s. I would prefer the 6000s.
     
  7. Kevin P.

    Kevin P. Well-Known Member

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  8. tgalx3

    tgalx3 Well-Known Member

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  9. Nomercy

    Nomercy Well-Known Member

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    At least 3-4 months