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Thread: AGM Equalization - Some Benefit

  1. #21
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    Jon, your 87 liberty was the same as my Liberty, or a least very close, so you are very familiar to the floor plan. The main electrical panel is approx. 3-4 feet aft of the electrical bay. I mounted the magnum controller in the salon panel and tried fishing wire to the electrical bay..... tough, if not impossible. I clipped the old inverter controller wires and soldered in the new magnum controller.

    I think I'm lucky here..... I have the small electric BBQ in the opposite bay. It doesn't fit the size of steak I like anyways... so I won't miss it. It is a single designated appliance 30A with a breaker on the panel. I could wire this to the transfer switch on the inverter so that the inverter will charge the house batteries. Label it - house battery charger.

    This should work.......right? I think it is worth the effort.

  2. #22
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    The installation requirements of your inverter will determine the circuit breaker required.

    Remember, you could be transfering or inverting up to 30 amps, plus you need additional input power to handle the battery charging and that could draw as much as 20 amps.

    On my current coach each inverter is on a 50 amp circuit. The output is 2500 watts. Wires are sized appropriately. The actual wiring is not complex, but getting new wires where they need to go could be involved because you are not replacing a component, you are actually adding one.

    I added a 12 CD pllayer to my coach last year and I wanted it to look like it was installed from new. To run the wires with the other wire bundles was a pain and that took more time than anything because I had to disassemble so much.

    What you want to do can be done, and the ease with which you do it depends on how easy it is to run the wiring you need.

  3. #23
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    Thanks Jon, You have been great help.

    The specs on the inverter is a 30 Amp AC input - transfer switch. The max. output is 16 amp for the charger.
    I think the electric kenmore BBQ breaker on the AC panel is a 30 amp but will have to confirm that. The weakness here is the wiring size but will check that out also.

    I will only connect if all requirements match... We don't fool with this electrical stuff. I fight fires for a living and I don't want to be discussing my actions with my fire investigators.

  4. #24
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    Obviously the people building the inverter know the requirements and if they call for a 30 amp circuit for input that is all you need to provide.

    Since you already have the breaker, it seems you only have to run the input wire. I am assuming the output from the inverter transfer switch is already in place. Since your original inverter did not function as a charger, and you probably have a manual selector switch to select the electrical (120 volt AC) input source I am guessing you will have to isolate the inverter circuits from the rest of the circuits in the 120 volt panel. The inverter supply can remain, but those powered through the inverter transfer switch (probably some outlets, a microwave and TV) will need to be on a separate bus bar isolated from the other 120 volt circuits.

    Typically those circuits will be located near the end of the bus bar and the bus bar will be cut, separating those circuits. The supply coming through the inverter transfer switch will then connect to that short section of bus bar.

    It may involve moving a few breakers and relocating the labels but I don't think that will be difficult.

    I like your comment about discussing your actions with fire investigators.

  5. #25
    jelmore Guest

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    Quote Originally Posted by truk4u View Post
    My house batteries are whimpy, when unplugged, they go to 12.4 almost immediately. With nothing to lose, I equalized them for 3 hrs at 15.5.

    Batteries are now at 12.8 when unplugged and still had 12.4 after 7 hours of no shore power with just the fridge and a fan running.

    Tom, after reading this I'm interested in equalizing my batteries. Checked the manuals, talked to Lifeline and talked to Xantrex. I have 3 8D AGM batteries and 2 Freedom 2500s inverter/chargers. Lifeline said yes, the AGMs will benefit greatly from equalization. Xantrex said they don't support equalizing AGMs, but if I do, to equalize from only one inverter/charger and to disconnect the other inverter/charger from the batteries. Their manual says to disconnect all 12V loads when equalizing.

    Did you follow all of that? For me, disconnecting the one inverter/charger leaves me without a water pump. Also, I wonder about the high voltage during equalization affecting any 12V house items, like lights.

    Can you detail how you did the equalization?

  6. #26
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    Jim, I think I remember equalization taking about 8 hours, but I see Tom did three. Regardless of how long I would try to do the equalization when you can do without whatever circuits will be affected.

    I would definitely avoid using the DC circuits when equalizing but I don't think we can turn off all 12V stuff (or 24V) because there is so much that is "key off" always working in the background such as the alarm system, clocks, dash radio and sound systems, etc..

  7. #27
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    Jim,

    I didn't do any of that stuff. I just followed the inverter instructions for equalizing and it did help for a short period of time, but the real cure is new batteries. If I remember, I cut off the house 12 volt, but there were still many 12 volt sources that had no adverse effect from the high voltage during equalization.

  8. #28
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    Also remember when discussing/thinking about battery voltage, that without a charge and ANY load, 12.9v is considered fully charged, and 12.1v is considered at 50%, or needing recharged. Also, the voltage drop-off is not linear and a good indication of their start of charge. Due to internal resistances, depending on the load on the battery/bank, voltage may be down to 11v, or at 12.1v before needing recharged. Just some food for thought.
    The reason Xantrex does not "support equalization" for AGM batteries is that they, or many charger manufacturers, do not want to be responsible for the cost of a set of batteries because they were destroyed. AGM batteries only have overpressure relief valves, they do not have vents. When the electrolyte is burned off, it cannot be recovered like a liquid battery (by adding more electrolyte). The same is the case with gel batteries. With overvoltage, gassing WILL occur, releasing the electrolyte, and causing hydrogen gas pockets in the gel/wicking material. This results in lower surface area for the chemical reaction that allows electron flow from plate to electrolyte to plate, and thus current flow through the battery. Overall, decreased battery high-current capability. The short-term equalization voltage does, however, reduce sulfation on the plates, which in small durations helps increase surface area for the reaction. It's a gamble to equalize gel and AGM batteries. It can, however, get you a little more life out of them if done for very short durations, and I don't mean hours. Hope this helps someone.
    Ben

  9. #29
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    Ben,

    Very good post,

    Alek

  10. #30
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    Good tid bits of knowledge today Ben.

    Thanks, JIM

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