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Help me with battery choice and connection (pretty please)

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  • Help me with battery choice and connection (pretty please)

    I'm an electronics idiot, but I have a small project

    I'm creating a system to water my 4' tall strawberry tower (8" hollow core PVC mounted vertically with 2" holes drilled throughout). The tower will have a non-soil modified gritty mix (see garden forums if interested). The mix dries out, so will need to be watered frequently.

    I purchased a 3.6w (12v .3a) DC pump and a JVR Online 12V timer. The tower will be inside a large planter filled with water and fertilizer and the pump will run (pending checks) for 20 minutes every hour 12 times a day. This should be 1.2 amp hours plus the timer (which should be well under 2 amp hours for the day).

    Solar charging doesn't seem feasible due to panel size and wife factor, so I'll be charging the battery weekly or so with a CTek US 3300 (will do AGM batteries).

    The timer has tiny wires, so I need to figure out a) the 'right' battery and b) what I need to buy to connect the battery and timer.

    'Right' in this case is something that is maintenance free, would last two weeks or so between charges, will last 3 years or so and is cheap. I'll store the battery and timer in some form of plastic container to keep the weather out.

    Thoughts? The contender in my mind (hah!) is an Interstate Batteries 12V 35AH Sealed Lead Acid (SLA) AGM Deep Cycle Battery (DCM0035) Insert Terminals from Amazon. Not even sure how I connect this to my timer.

    Thanks for the input.

    Andrew
    Last edited by AndyInNYC; 03-18-2021, 11:20 PM.

  • #2
    Anyone?

    Comment


    • #3
      This doesn't sound difficult, assuming that you're comfortable with wiring something like this. The timer seems like a suitable choice. The connections to the timer are by normal size spade lugs, not tiny wires. My only concern is whether the timer is suitable for DC loads. The datasheet that I saw says 250VAC/16A loads are OK, but doesn't mention DC loads. But one of the youtube videos shows it driving a DC load, so it is probably fine.

      pump.jpg

      Your choice of battery is also fine. As you say, you will have the charger replenishing it. Come to think of it, do you really need a battery at all? Could you simply get a 12V AC adapter that supplies 12V at 2A and use that to drive the pump through the timer?

      wallwart.jpg
      Timer: https://www.amazon.com/dp/B00WR0ELCO
      Charger: https://www.amazon.com/dp/B000FQBWCY
      AC Adapter: https://www.amazon.com/dp/B0852HX9HV
      Attached Files
      7kW Roof PV, APsystems QS1 micros, Nissan Leaf EV

      Comment


      • #4
        Bob,

        Thanks for responding. In fact, I'm not comfortable wiring anything. That's the problem.
        The timer is: JVR 12V Timer Switch Programmable Digital 12 Volt DC/AC/Solar Battery Powered - so it directly claims DC.
        The wife-factor prevents running a power cord out through the deck to power this - the battery in a box sitting behind is acceptable.

        The timer wires have spades on one end and plain wire on the other. The pump has two plain wires coming out if it (hard wired/can't be replaced). I"m assuming that I'll need, due to length, to have someone solder and shrink wrap longer wires to go from the pump to the timer (I don't solder). They may be long enough depending on how I place the battery box. I'll still need them soldered together anyway (am I right that just twisting them together isn't a great idea?).

        I don't understand what I'll need to go from the bare wire end of the wire with a spade going into the timer to go to the battery - tiny wire/big battery. I'm assuming the wire length is fine since the timer will sit inside the battery box.

        Your first diagram seems to have the trickle charger running to the pump - I'm thinking that I'm just going to hook up the trickle charger every X days for a few hours in the evening; I'm not leaving it out in the box. Do I need to detach the timer when i charge?

        Clearly I'm a little lost, so a little more hand holding would be appreciated.


        Andrew

        Comment


        • #5
          Andy,

          Thank you for the extra details. That makes sense. I didn't realize that you won't have AC power at the pump.

          I bought a "fancy" crimp tool on Amazon and am very happy with it. It makes reliable crimps with no skill required. It is called Hilitchi Crimper HS-30J. https://www.amazon.com/dp/B01IQIALJC

          There are cheaper crimp tools that don't work as well. Get a good one and you won't regret it.

          You don't need to solder. With this tool, you can put a spade or push-on connector on a bare wire. You can also splice together wires with this tool. Another way to splice together wires is with "wire nuts" but if you are crimping one place, crimp them all.

          This picture shows a kit of crimps for joining wires, a good crimping tool, and some crimped wires. Of course, you won't need this many, but it was the best picture I could find. They use standard colors, red for thin wire (high numbers like 16-22), yellow for fat wire (low numbers 10-12), and blue for in-between wire (14-16). Your crimp tool will also have these colors on it.

          Ideally, you would find an assortment of crimps, with some for slide-on and some for splicing. Having extras is good. Practice on some scrap wire before starting something important. If you can pull hard and the wire stays in the crimp, you have a good connection. There are also some good youtube videos showing how to crimp wires.

          61LouamHM4L._SL1000_.jpg

          The battery will have slide-on connections. You can crimp mating terminals onto wires and onto the charger cable.

          Just make sure that you always connect the + terminals together. Electronics will die if you wire it backwards.

          The picture that I found for the JRC timer shows slide-on terminals for all four connections:
          51zt3i9ieYL._AC_SL1001_.jpg

          I hope this helps. Keep asking if you have more questions.
          7kW Roof PV, APsystems QS1 micros, Nissan Leaf EV

          Comment


          • #6
            The wires INTO the timer are slide on.
            I don't know what connector I need to attach to the bare wire other end to attach to the battery (that battery in particular). The description says "insert w/bolt replaces flag ty" - I have no idea what that means. I'm assuming I'll need to buy a pair of these (whatever they are) from Amazon or PepBoys.

            Alternatively, I'm happy to stick the whole thing in a bag and send it to my repair guy, bob-n, to crimp and send back <g>.

            Additionally, is my battery choice a good one or is there a better battery (a little alliteration there) in the 35ah range?

            Thanks for your input towards my education.


            Andrew

            Comment


            • #7
              https://www.amazon.com/Sealed-Lead-A.../dp/B005CLPOQM

              One of the Q&A on Amazon reads:
              Question:
              what size bolts for the battery leads?
              Answer:
              The data sheet says it is 1/4"-20, but that is definitely *not* the thread on the battery I just received. It has about 26 threads per inch, and it is 5.8mm diameter. The battery came with two bolts and washers that fit the threads perfectly.

              If true, you need a crimp eyelet with a 1/4" hole, like the picture below. Attach wire to it with a crimper, put the bolt through the eye and bolt it to the battery.
              NEYRD04.jpg

              Seriously, if I could help you in person I would, but I'm nowhere near NYC.

              As to what battery is best, it's more complex. Most lead-acid batteries are good if not overworked. You'll get the longest life if you don't discharge the battery too far. In other words, the more often you recharge, the longer the battery will last. If a smaller battery will be easier for you to carry into the garage and will be recharged more often, then a smaller battery might be better. If money is your main concern, go with the cheapest big battery you can get. You might even get by with a car or truck battery that someone is tossing. An old car battery might be too feeble to start a big engine, but fine for this little pump, especially if you recharge it often. And if you get it for free, you won't care if it wears out after a year.
              7kW Roof PV, APsystems QS1 micros, Nissan Leaf EV

              Comment


              • #8
                Bob,
                Given the cost of buying the crimper, leads (longer wire) and eyelets, it likely *is* more effective to pay shipping to you and back and a handling fee than buying all 3 for one use. I'm an old dog, so this likely isn't going to suddenly become my new hobby. My wife becomes concerned when I use a tool more complicated than a screwdriver.

                Your Private Messaging appears to be not enabled or I'd take this off-line with you.

                Thanks again for all the help.

                Andrew

                Andrew

                Comment


                • #9
                  A local service station gave me a battery so that I can test the pump's maximum lift. Supposedly the car owner just wanted to replace it - nothing wrong with the battery.

                  The battery is S46B24R GSYUASA. From what I can tell, this is the battery from a Prius.
                  Under the battery specs, if I can read them correctly, it seems this is a 12V 46Ah battery. What confuses me is the 60 minute Reserve Capacity. Not sure about any of this.

                  Aside from this being a car battery and not a marine battery, any reason why this wouldn't work for the project? Any idea how long it might last in the hot summer sun in a black box before it goes dead for good?

                  Am I reading the Ah correctly? Seems like this is the 'same' as the marine battery in power (except that you're not supposed to run a car battery down). Correct?


                  I can't find what the post size is - what size eyelet will I need?

                  Andrew
                  Attached Files

                  Comment


                  • #10
                    That's a good battery. It will work fine. Any lead-acid battery doesn't want to be fully discharged, whether marine or auto. This one is 12V, 45Ah, AGM. The terminals are "T3 Small Japanese JIS Terminal" which means metal posts. One post is

                    You are supposed to attach to those posts with battery clamps. You can get battery clamps from an auto parts store. However, bring the battery with you and make sure the posts match. These are smaller than normal size. Something like this would be good, but only if the holes fit the posts on your battery:
                    7175MyojreL._AC_UY218_.jpg
                    Here's the actual battery datasheet with a drawing of the posts. Dimensions are in millimeters.
                    https://www.yuasa.co.uk/yuasa/datash...ku/HJ-S46B24R/
                    The positive post is 14.7mm or 0.579" OD. The negative post is 13.1mm or 0.516" OD. More common batteries have 19mm and 17mm posts.

                    Attached Files
                    7kW Roof PV, APsystems QS1 micros, Nissan Leaf EV

                    Comment


                    • #11
                      So, after a few mis-starts (read mistakes), I have the pump running 16 cycles a day @ 4 minutes each. This seems to move enough water to wet everything down from top to bottom without draining the reservoir.

                      Thanks to everyone; it took a youtube video or two before I finally got the leads to the timer plugged in correctly.

                      Question on charging the battery:

                      I'm using a CTEK 3300. The CTek has a motorcycle, car and cold weather/AGM setting. The Prius battery I'm using (see above) is an AGM. Should I use the regular car or the cold/AGM setting? I can't find enough information online to be sure (user error, not information error <g>). I *think* I use the AGM setting, but I'd like a confirmation from the informed.

                      Thanks again.

                      Andrew

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