Battery AH vs CCA question

icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
Here is a question I should know the answer to, but I don't.

I have a friend who just bought truck camper and needs a battery for it. In "doing the math" as is say, we have determined that he needs a battery in the 230 ah range (12vdc). In looking for "deep cycle batteries" all I seem to get are battery specs in CCA and minutes of reserve.

Anybody have A: a simple way to do a conversion, and perhaps more importantly a battery recommendation for a starter. (I know that he will kill it pretty quickly) so cheaper/shorter lived would probably be better.

As always, Thanks in advance for all the help,



  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Battery AH vs CCA question

    now does he intend to start it with this battery for cca is for starting batteries? they, if memory serves correctly, have more thinner plates crammed for higher starting currents and are generally not suited for most of the applications on this forum. there isn't any conversion and i thought you knew that by now.
    a pair of t105s in series should be about right.
  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: Battery AH vs CCA question

    No starting, just lights, fans water pumps etc.

  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: Battery AH vs CCA question

    I do "sort of know that by now". He can't fit a pair of T-105s which is what I suggested, but what in the 12 volt "deep cycle" world might make a good replacement. His big issue is that they will camp for 5 days at a time without means to recharge. (I am going to try to talk them into a Pv system,, but this is new to them and he want to go buy a battery,,,tomorrow!

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Battery AH vs CCA question

    Tony -

    Since you can probably find Interstate batteries just about anywhere ...

    The "features & specs" tab gives a listing of different sizes & capacities. These are, of course, the "hybrid" deep cycles, not "true" ones.
  • mike95490mike95490 Solar Expert Posts: 8,613 ✭✭✭✭✭
    Re: Battery AH vs CCA question

    His camper likely has battery boxes sized for Group 24 or Group 27 batteries,
    if I recall, group 24 is about 85AH and 27 is about 105ah - give or take on salespitch.
    Get the size of the box, and match it to the battery size.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    gen: ,

  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: Battery AH vs CCA question

    its gunna take more than one deep cycle battery to last 5 days,, with no recharging.. unless the deep cycle is about 800 ahr
  • KamalaKamala Solar Expert Posts: 452 ✭✭
    Re: Battery AH vs CCA question


    Sorry to learn that you got hit before the lightning protection system was installed. ;)

    What is your friend's usage? The very knowledgeable and helpful people on this forum could do him more service if they knew his requirements/plans/expectations.

    Just funnin'.:roll:

  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: Battery AH vs CCA question


    We've gotten hit several times over the years. This last one was ~5 years ago and took out some minor stuff including a charge controller. Over the years we have lost radio transmitters, outside wiring, fuse boxes, (never a genset interestingly enough?)

    I'm mostly just trying to avoid burning the place down. Neigbouring island has lost 4 building that I know of in 75 years.

    JohnP. I think you misunderstood me. I have done the calcs and figure the maximum loads over three days, to draw the battery to a maximum of 50% SOC , the batter needs to be ~230 ah. I figure 5 days of loads equal ~120 ah total, ~24 ah (12vt)so that requires a battery in the 230 ah range.

    The group 29 interstate makes ~120 ah at the 3 hour rate. Wouldn't be my ideal choice, but it is all that fits in the box. We're going to try one and see how much draw happens on his first few trip(s), and look to see what happens. Ideally his loads are smaller than expected or we will have to think about a small Pv system.

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