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howardwheeler's avatar
May 31, 2016

Time to replace batteries. How?

I have a four battery bank that is charged by a Xantrex PS2000 pure sine wave inverter charger. I have 4 12v large deep cycle batteries bought at Sam's Club. I think you call them 31 size (not sure but they are the biggest they have). Anyway they are a little over six years old, and I had to leave my trailer unplugged for about 12 hours, and the charge was way low after that. My warning lights for low batteries were blinking. I have kept water in them with those easy fill contraptions attached, and I periodically have equalized them. So I think my batteries are on the way out. The inverter only had to run the residential frig. Everything else was off. They did charge back up after I plugged in but I'm concerned that such a large bank discharged so quickly. Anyway, how do I go about changing the batteries? Do I need to shut off the inverter charger? Can I just transfer wire for wire or is there an order I should follow? Anything special I should watch out for? Any help is appreciated. I'll probably do it next week.
  • the bear II wrote:
    I haven't had any experience running a residential refrigerator using an inverter and batteries. I would expect after 12 hours the refrigerator would significantly deplete the batteries.


    We have had our 18 CuFt residential fridge for 1-1/2 years and don't have a power problem when dry camping. We shut down the main inverter at bed time, around 10 PM and leave the inverter that's dedicated to the fridge on. If the bank reads 12.7 at 10 PM it will usually read 12.5 to 12.6 at 7-8 AM when I get up. Not much loss as the fridge is very efficient and only takes 1.25 amps of a/c to run it.
  • RoyB's avatar
    RoyB
    Explorer II
    Just be aware that the replacement battery from SAMs CLUB or anyone else even with the exact model number may be different where the BATTERY TERMAINALs are located.

    Observe which cables are one which terminals identified by the the word POS or NEG or the symbols = or - stamped into the battery case.

    The NEG or "-" cables always goes to frame ground on the 12VDC batteries...

    SAMS CLUB also sells 6VDC batteries so be sure you have one or the other. This is a typical wiring lay out for both 6V and 12V batteries...



    Use your CELL PHONE CAMERA to document the wiring of the terminals before removing them... If there is a bunch of wires I would use RED FINGERNAIL polish on the ones that connect to the POSITIVE TERMINALS...

    Roy Ken
  • I haven't had any experience running a residential refrigerator using an inverter and batteries. I would expect after 12 hours the refrigerator would significantly deplete the batteries.
  • FIRST ALWAYS FIRST BEFORE STEP NUMBER 2

    • WEAR SAFETY GOOGLES AND GLOVES!
    • Take at least four images of batteries with cable wiring intact
    • Disconnect negative cable ends, one by one and wrap with black electrical tape for ID and shorting proofing
    • Disconnect positive cables one by one and use masking tape on the metal for ID and shorting proofing
    • The best lifting device I have used is a lever clamping assembly with grip pads and bicycle handlebar lifting grip
    • I have made lift ropes by squeezing on cable lug ends that were first dipped in GOOP®
    • Protect your spinal discs while lifting DO NOT SWIVEL your back while lifting
    • Before placing first new battery review your images to get placement orientation correct
    • When all batteries have been replaced recheck your images before connecting cables - you will not get a second chance
    • Then smear a healthy dose of silicone dielectric grease on all shined-up metal surfaces, battery posts and lugs
    • All electrical metal should gleam like new
    • Smear a gob of dielectric grease on hold-down studs and nuts
    • Take your time! A reversed polarity mistake can cost a fortune
  • Shut down all power, unplug the RV. If you have solar pull the fuse/turn off the breaker. Take good photos of the wiring and if at all possible label the wires. Remove the ground (-) to the coach first then the other negative wires off the bank. At that point you should be safe. Clean all the cable ends with a wire brush. Reverse the process to install the new batteries and spray the terminals with anti corrosion treatment (found at auto parts stores). The last connection is the main negative/ground wire to the RV.
  • Unhook the chassis ground before you touch anything else and hook up last. Make sure you hook them up exactly the same way, take a picture before you start pulling cables and note + and - posts. And don't drop a screwdriver or wrench across the posts, this is really important.:)

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