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Charging a AGM deep cycle battery

Discussion in 'Electronics & Gizmos' started by blair, May 25, 2020.

  1. blair

    blair Well-Known Member

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    I just my new AGM 170AH deep cycle battery delivered for my JW watersnake whats the best way to charge these batteries? I checked the voltage then put a 4 amp charger/maintainer on it , but I have read that a multi stage charger should be used.
    thx
     
    diesel likes this.
  2. diesel

    diesel Well-Known Member

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    Definitely a multi stage Blair, something like a CTec. I use a CTec 25 amp charger for the AGM 120ah in my caravan and can't fault it.

    Jeff
     
  3. blair

    blair Well-Known Member

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    Thx for that Jeff I presume it will be ok for first charge whith 4 amp cat CBC4WAU charger, I wiil have a look for a CTec.
     
    diesel likes this.
  4. diesel

    diesel Well-Known Member

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    A 4 amp trickle charge won't hurt the battery, but a multi stage charger keeps on evaluating the state of the charge and compensates as required by delivering a boost charge or an absorption charge. Most trickle chargers just keep on pumping in power without reducing the charge rate where a multi stage will cease charging once optimum storage is achieved and then maintain the voltage at 12.7 volts.

    Jeff
     
  5. blair

    blair Well-Known Member

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    What is the model/description of your 25 amp CTec and is it 240 volt and solar panel compatible, I presume all AGM batteries are deep cycle a 25 amp should be fairly quick as well my 4 amp would take 42.5 hours to charge a fully discharged 170AH battery cant have that on a fishing trip! I will hook it up to the outboard charger as well if possible.
    I looked on the CTec site they have many chargers and look the goods.
     
    diesel likes this.
  6. diesel

    diesel Well-Known Member

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    XP2500, but it's obsolete now and they have been replaced by the MXS25.
    I've also got 2 MXS15 chargers, one mounted in the back of the Ranger for charging the auxiliary and the other is used to charge a bank of 2 x 120 amp deep cycle lead acid batteries in the shed when solar can't keep up with it.
    As you have probably checked out already, Ctek do a range of marine designated chargers with the M300 being the 25 amp version and the M200 a 15 amp unit. Maybe you only need a 15 amp, it will recharge your battery just as good as a 25 amp will, only takes a little bit longer. A 15 amp charger will fully recharge your 170 AGM overnight no worries at all.
    As far as I know, the only Ctek chargers that will handle solar input are the dc/dc units and they are rated pretty good, but if you're looking to recharge your battery by solar as well as using a multi stage smart charger then any mppt solar regulator will do the job without forking out a heap of cash for a top shelf gizmo.
    Have you got a solar panel mounted on your boat?

    Jeff
     
  7. blair

    blair Well-Known Member

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    Thanks again Diesel you know your battery chargers, thought you would, I nearly fell out of my chair at the prices of the 15 to 25 amp models most other brands are similar priced. I will get at least a 15 amp needs a good boot to recharge those batteries in a reasonable time will look into hooking up the outboard charger as well, no I don't have a solar panel on boat but will look into that too probably a good idea to keep the main engine electrics separate. got the watersnake today have thursday and friday off apparently ,hoping to have it fitted before weekend I am out supporting the pensioners again.
     
    diesel likes this.
  8. diesel

    diesel Well-Known Member

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    We've been off-grid up here on our mining claims for the past 16 years and rely on 12 volt power for lighting and refrigeration plus running inverters for most other household power requirements.

    It was a big learning curve and it took a while to get it right. My early failures were due to being a tight-arse when it comes to buying the right gear to do the job, cheap batteries and chargers just wouldn't go the distance. I picked up a lot of good advice from other travellers on some of our long trips around the country and finally it all came together. It's a bit like fishing gear, spend a bit more on quality and the gear doesn't let you down.

    My next great leap in technology will be to replace my caravan AGM battery with a couple of lithium ion phosphate units. They are lighter and handle discharges far better than any other 12 volt batteries.

    Jeff
     
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