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Great big batteries for mobile operation

Discussion in 'Mobile Radio Systems' started by VE7TOP, Apr 15, 2018.

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  1. VE7TOP

    VE7TOP Ham Member QRZ Page

    So I have acquired 3 Enersys PowerSafe SBS 190F AGM 190ah batteries to install in my Landrover to support a mobile/portable HF operation. At the moment I have one of these installed but I could put 2 or even all 3 on board. There is however a fair amount of inertia involved when moving these as they weight 132lb each. So the first question has to be how many batteries to put in the vehicle.

    The other question I have is how best to keep one or more of these charged. It's my (limited) understanding that the installed alternator probably provides too high a voltage to properly charge and maintain these for the long term. Is it possible to use a solar power controller fed by the alternator that would provide the right 'intelligent' charging for the proper maintenance of these batteries. Alternatively I do have an ICT intelligent charger which could be connected to shore power whenever the vehicle is parked in the driveway.

    I'd appreciate any advice or comments.
     
  2. US7IGN

    US7IGN Ham Member QRZ Page

    It depends on how often and for how long you plan to be away from the power grid. What equipment to use. And how much will these batteries cost.
    For ordinary 100 w radio and one battery will be enough.
     
    NH7RO likes this.
  3. VE7TOP

    VE7TOP Ham Member QRZ Page

    Initially this will only be powering a 125 watt transceiver and likely not operating remotely more than a weekend.
     
  4. KF5LJW

    KF5LJW Ham Member QRZ Page

    One is more than enough and overkill. You might also consider an Electronic Battery Isolator as that will allow your engine alternator to charge the battery when the engine is running. Do not use the mechanical relay types because sooner than later you will weld the contacts together. With the isolator there will not be a need to remove the battery to charge it.

    Even though you have a 125 watt transmitter you will never come close to pulling full current of 20 amps if you are operating SSB. During transmit over average maybe 5 to 7 amps, and RX around 1 amps. So when averaged out less than 5 amps. On a 190 AH battery is roughly 40+ hours non stop operating if you do not stop to breath.

    One of the battery Electronic Isolators is made by Cooper Industries under the brand name of Sure. Just select your vehicle brand because it will interface to the alternator voltage regulator, number of battery ports, and size in amps which 70 is more than enough for you. Even if the battery is dead only takes 5 hours to charge. I work with Verizon wireless and most our tech use something similar because they use a lot of electronic equipment and use a 2 or 3 batteries to run all the equipment. Even out tower contractors use it with large winches. So the $50 to $70 for the Isoilators is an excellent value and will keep that battery in top shape with no fuss or hassle. Even less expensive than an external charger. Just drive and forget about it. Top models even have an emergency bypass switch that will allow you to start your vehicle with the House Battery if your vehicle battery fails on a cold winter morning.
     
    K8AI, NH7RO and K0PIR like this.
  5. VE7TOP

    VE7TOP Ham Member QRZ Page

    Thanks for the information. it is much appreciated. I probably should have mentioned in the original post that I do have a battery isolator (Wirthco - Battery Doctor 150 amp isolator) in place with 150 amp fusing between the main battery and the isolator and fusing between the isolator and the auxiliary battery. Cable is #6 between batteries. This isn't connected up yet but is ready to go now that I have the auxiliary battery.
     
  6. KF5LJW

    KF5LJW Ham Member QRZ Page

    FWIW a 150 amp fuse is way too large for a #6 AWG, and there is no reason to require 150 amps. 50 Amp fuse would be more than adequate and safe for 6 AWG.
     
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  7. K0BG

    K0BG Platinum Subscriber Platinum Subscriber QRZ Page

    Great advice! A 150 amp fuse will handle an overload long enough to burn a 10 foot run of #6 in about 30 seconds, and never damage the fuse! And you're also correct about the 50 amp fuse.
     
    NH7RO likes this.
  8. US7IGN

    US7IGN Ham Member QRZ Page

    It all depends on how often you will start the engine to charge the battery. For example, if you are driving all day and stopping in the evening for spending several hours on communications, then one battery will suffice. Even if you stand for several days in one place, start every few hours the car for charging the battery when you on the air. It will be easier and cheaper then buy more expencive batteries that all the same need the charging.
     
  9. KF5LJW

    KF5LJW Ham Member QRZ Page

    Thanks being an electrical engineer for 40 years helps. Minimum wire size is determined by the Fuse or Breaker size. 50 amps is more than adequate to charge the battery and run the rig without nuisance tripping. The resistance of the fuse, wire length, and battery internal resistance will limit charge current to less than 50 amps. I assume the wire he is using is an automotive type with at least a 105 degree C insulation rating. So the fuse can technical be a little larger. But at 50 amps is more than adequate for the job and conservatively safe even using a lower temp 75 degree insulation used in a home.

    Keep it safe
     
    Last edited: Apr 16, 2018
    NH7RO likes this.
  10. WD0BCT

    WD0BCT Premium Subscriber QRZ Page

    The biggest battery available rather than optimum battery required has some associated negatives in addition to unnecessary weight. I've witnessed the aftermath of battery short circuit failures...one in a a '63 VW Beetle...the other in a USAF computer installation (125VDC battery bank). Both were pretty amazing failures...the big battery failure was really amazing. If you acquired 190ah batteries rather cheaply one can't look a gift horse in the mouth. If it were me I would not lug all three around...diminishing returns with increased weight and accident potential.
     
    Last edited: Apr 16, 2018
    K8AI likes this.

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