Separate AGM battery charger for RV solar?

JoneszJonesz Posts: 18Registered Users
Hi all; got some good info the last time I asked so am going to the well again: Going to order some solar equip for my RV which will have 2 AGM 12V (220AH total) tied together and a 12V flooded cell on separate crcuit for backup. I am going for a 135W Kyocera panel and a morningstar 15A MPPT controller. My thinking is that the converter in my RV may not be the ticket when charging and maintaining my AGM batteries on shorepower. Wondering how necessary or preferable it is to have a dedicated charger as I would order it at the same time to avoid additional shipping costs etc. I have been looking at an Iota 30 amp with IQ4 to make it a true 3 stage unit. It apparently has a switch allowing it to charge and float AGM batteries more efficiently reducing chance of damage to the AGMs? Any and all help appreciated
Jonesz

Comments

  • mike95490mike95490 Posts: 6,290Solar Expert ✭✭✭✭
    Re: Separate AGM battery charger for RV solar?

    I don't personally like the Iota for shore power charging, even with it's module. I don't think it really does a true 3 or 4 stage charge. I belive they are more of a "constant voltage" power supply, and the add on module just tweaks it a bit. Make sure what you are getting has remote thermal to mount at the batteries, and a specific setting for AGM.
    I have an Iota, but only use it for bulk when solar is low. I never thourghly checked out the IQ module actions.
    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

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • JoneszJonesz Posts: 18Registered Users
    Re: Separate AGM battery charger for RV solar?

    Mike do you have any suggestion for what you might consider a "good" charger. I read on the Iota site that what you say is quite possibly true and it may not be any better than the converter in my fifth wheel for charging my AGMs.
    http://www.iotaengineering.com/dls30.htm
    So that being said I am still looking for a suggestion as to a good charger to use, if I require a dedicated charge system?
    Jonesz
  • mike95490mike95490 Posts: 6,290Solar Expert ✭✭✭✭
    Re: Separate AGM battery charger for RV solar?

    Try the XW true charge http://www.solar-electric.com/xatr1220bach.html
    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

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • dwhdwh Posts: 1,332Solar Expert
    Re: Separate AGM battery charger for RV solar?

    What converter/charger do you have in your RV?


    The Iota is a 2-stage converter/charger by default. The IQ module changes it to a 3-stage + automated EQ. That's important when charging AGM because most AGMs are not supposed to be equalized (they don't need their electrolyte stirred and over-voltage can cause them to pop their seals) - and there is no way to turn that function off with the IQ module.

    While this gets disputed, it is recommended that if you are going to charge a battery -while it is supplying a load-, then you should use 2-stage. The reason is that a load can cause the "apparent" voltage of the battery to drop, thus fooling the 3-stage into overcharging the battery.

    According to that theory, 2-stage is best for charging loaded batteries, and 3-stage is best for charging batteries that are not loaded. Samlex 3-stage chargers have a dip switch so that you can put them in 2-stage mode (what they call UPS Mode) if you are charging loaded batteries.


    A converter/charger is designed to supply the loads, while also charging the battery. What you have in your RV is almost certainly a converter/charger. The Iota without IQ is a converter/charger, and the Samlex in 2-stage mode is also a converter/charger.

    There's no reason that you can't use the converter/charger in your RV to charge your batteries unless it has voltage set points that are inappropriate for your batteries.
  • JoneszJonesz Posts: 18Registered Users
    Re: Separate AGM battery charger for RV solar?

    Yeah I'm starting to think that my converter in the RV is just as good as these other chargers. When the snow storm here stops I am going to go out and figure out what I actually have for a converter/charger. I am thinking it is a 45Amp according to some spec sheets I have seen. Will then figure out it's charging and maintenance voltages. Thanx for the help.
    Jonesz
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