House batteries

[Billysurf]

I know nothing about house batteries.  The first week we had the bus I left the fridge on for a couple of days and it drained them dead.  My inverter was sending out a high pitched tone so I turned it off.  I was told by a few people they would never come back.  Others said they would with a "trickle charge."  Nothing on my 50 AMP coach powers up by 15 AMPS in my tests but when hooked up the coach to my 3500 generator I noticed that the batteries have come back to life (once generator is off and no power is going to coach, lights work etc.).  I do have another onboard 7000 watt generator that is being repaired this week.  My question is, is there a meter of some sort I can use to test the level of power in these.  And assuming there is, what am I looking for?  A meter is attached to these batteries BUT the previous owner said it never worked.  I'd love something I can use myself, not have installed by electrician.

[bobofthenorth]

You need to do a lot of reading or plan to open your wallet wide.  Batteries have a finite life and most of them don't die a natural death - they are killed by unknowing owners.  The short answer to your immediate question is - "Yes, there are meters available which will measure level of charge on your batteries".  The longer answer is that, until you understand the implications of your use pattern on the life of your batteries you won't be able to intelligently use the output from the meter.  I've used Trimetric 2025 meters and been happy with them but there are other options.  Right now I've got some cheapo Chinese POS in transit between Hong Kong and Buchanan for a project I'm working on.  Bogart is pretty proud of their Trimetrics and I've got a pretty good understanding of how batteries work so I'm willing to take a flyer on the Chinese junk but I wouldn't recommend that route for everyone.  You can spend a lot of money on batteries and burn them up really fast if you don't look after them.  Discharging them the way you just did with yours is a sure way to kill them.  The easiest way to understand battery care is to remember that any conventional (lead acid, AGM or Gel) battery has a finite number of discharges in it when you buy it.  That number is lower the more completely you discharge the battery and higher if you restrict your use to the "top" of the battery.  Running them down until they won't turn the lights on is absolutely the worst thing you can do and you can consider that if you do that 3 or 5 times you have ruined your batteries.

[Oonrahnjay]

    If you can get a batteries to accept a charge, you may be able to bring the batteries back.  If they're drawn all the way down - below about 40 - 50% - they may reach the sulfate stage; a chemical reaction will cause sulfate to form from the sulfuric acid in the battery and if that happens and the sulfate layer is heavy, the battery is likely dead and cannot be brought back.  However, you stand a chance that a strong charge will dissolve the sulfate if it's a "light" amount of sulfate.  The best thing is to reinitialize the inverter/charger.  The charger function of a (modern, advanced) works very well.   Most will allow you to program an "Equilizer" charge -- that's a brief blast of charge that's about 2 volts higher than the normal charge, and it will often be enough power to break through sulfation and allow each battery to take a charge.  So, if you can get the shore power feed back on, the charger that's built into your inverter is likely to be your best bet.
   
    On my Outback inverter, if the batteries are down (like if the handyman at a campsite unplugs my shore cord so he can mow around my bus and doesn't plug it back in ... grrrrr), and I plug the shore cord (50 Amp) back in, nothing will happen -- the inverter has to see "feedback" from the battery before it will begin to charge.  What I've found is that if I run a regular extension cord from an ordinary 15 Amp socket and put a battery charger on one battery, that little power pulse is enough to make the inverter "see" the battery feedback and from then on the inverter will stay in charge mode and charge the batteries fully -- if they'll accept that charge, anyway.

     The fact that running your generator has charged the batteries up at least somewhat is a good sign.

    A couple of questions ... what's the brand and model of your inverter?  Also, are the house batteries "sealed" or "maintenance-free"?  If they're sealed "glass mat" (AGM) batteries, they will withstand being drawn down better than wet/acid batteries; although, if a battery is really drained, it doesn't matter a lot what type it is.

    I bought a cheap battery load tester from Northern Tool.  To test a battery, you really need a tester that puts a load on the battery -- just using a meter to read the voltage is only going to give you a very rough idea of the condition of the battery.  But I think your first priority is to get the inverter/charger back in action and apply a charge (most inverter/chargers use a "smart charge" function and so they'll apply the most effective charge to your batteries).  Good luck getting them to take a charge again!  (BTW, if they're really down but you bring them back, there's a chance that they will only take a partial charge; if this is the case, they're terminally ill and only on life support but they may work for you for a while if you don't load them too hard).

HTH,  BH  NC

(EDIT -- PS, I agree with everything that Bob has said above.)

[bigred]

AND ,Make sure you use "deep cycle" batteries .These are made to discharge and recharge.    Sams Club for under a hundred dollars each!!!

[Oonrahnjay]

   Oh, and a couple of other things.  A battery and the charge function is affected by resistance and the most likely place for resistance is in the battery cable connection.  Yours look pretty clean but anytime you have major battery maintenance, it's good to clean the battery terminals and cable terminals and reinstall them to get a connection.
  Also, if a battery is dead in the string, it can kill the entire battery function.  If you can't get any life out of the battery system with a charge from the inverter/charger, then you may be able to get your system working again at reduced capacity by removing each battery and see if it will take a charge from a plug-in charger.  If you find that only one will not charge up, you can reinstall the other three and get at least a little function from your house batteries at least temporarily -- of course, your storage will only be 3/4 of the amount of the "full" power from four batteries.
  Another note, if one battery is dead, it's usually not a good idea to put in a new battery with a string of older, possibly-damaged batteries.  Sometimes, it works but often the only way to restore a genuinely-damaged battery bank is to replace all batteries.

(EDIT - Sorry, looking at the photo, it appears that you have three batteries in your battery bank.  Change everything above I said about four batteries to three, and if you have to remove one bad one temporarily, you'll only have 2/3 of your full power.)

[Geoff]

If your inverter was giving you a warning squeel it means you still had some battery power left and the inverter stopped inverting to 120 volts.  Most inverters cut off around 11.5 volts to save your batteries.  I use a Harbor Freight battery tester with a 50 amp load which works well. They also have a 100 amp model.

--Geoff

[Iceni John]

You may want to consider adding some solar panels.   They would have prevented your mortally wounding the batteries (because they probably are now terminally injured and not much longer for this world).   Even just a few hundred watts of solar will keep your batteries from completely discharging, provided you don't have a large load constantly on them.   Unless you live in the Pacific North Wet or somewhere that rains a lot, solar makes sense, especially for unattended RVs/buses/cabins/boats.   PV panels are now well less than a dollar a watt (you can sometimes find PV for less than $0.50 a watt!), so it's more cost-effective than ever before, especially now that batteries are becoming pricier all the time.

I like knowing that my batteries are always being charged every day to 100%, whether I'm there or not, for free.   OK, I know nothing's really free, but solar can easily pay for itself if it prevents you killing an expensive battery bank.

John   

[Geoff]

I noticed the price of batteries has jumped the last couple of years.  I wonder why when the price of metal has gone down.  The battery core deposit also doubled.

--Geoff

[Dave5Cs]

If your bus is not plugged in and you leave your Inverter on and you have any phantom loads draining the batteries the inverter will use the rest of the Battery juice to re charge them until they are dead unless you have like mine that has a low battery shutdown. Even a Vanner will drain the batteries over time unless plugged in.

[belfert]

You may want to consider adding some solar panels.   They would have prevented your mortally wounding the batteries (because they probably are now terminally injured and not much longer for this world).   Even just a few hundred watts of solar will keep your batteries from completely discharging, provided you don't have a large load constantly on them.   Unless you live in the Pacific North Wet or somewhere that rains a lot, solar makes sense, especially for unattended RVs/buses/cabins/boats.   PV panels are now well less than a dollar a watt (you can sometimes find PV for less than $0.50 a watt!), so it's more cost-effective than ever before, especially now that batteries are becoming pricier all the time.

Sun Electronics has some 300 watt solar panels for around 30 cents a watt.  I paid 26 or 27 cents per watt for a pallet 22 panels I got for my house two weeks ago.  Price is a bit higher for less than pallet quantity.  Shipping is a killer on solar panels.  You can get smaller panels for closer to $1 a watt to save on roof space.

[bobofthenorth]

Sun Electronics has some 300 watt solar panels for around 30 cents a watt.  I paid 26 or 27 cents per watt for a pallet 22 panels I got for my house two weeks ago.  Price is a bit higher for less than pallet quantity.  Shipping is a killer on solar panels.  You can get smaller panels for closer to $1 a watt to save on roof space.

Us Canucks are getting screwed - nothing new in that - but it pisses me off nonetheless.  The absolute best I've been able to find is a buck a watt and you have to look hard for that.  Even allowing for the lame loony that's 75 cents in real dollars.  I guess the solar install will wait for a trip to Q.

[buswarrior]

Billysurf,

In your picture, both the battery cables come off the same end of the set of batteries.

That is sure death.

Get one of the cables connected to the far end battery post.

Electricity can be thought of as lazy, takes the shortest route.

In your set-up, the near battery is doing an unfair share of the work, getting an unfair amount of re-charge, and the far battery will be the first one to die an untimely death.

Google "wiring a battery bank" if you want to hurt your head, or just move one of the cables, if you don't.

happy coaching!
buswarrior

[Iceni John]

Buswarrior is correct, you have your batteries connected as in example 1:  http://www.smartgauge.co.uk/batt_con.html   Example 1 is not good, and ideally you should use examples 3 or 4.   The folk at SmartGauge have some good ideas about what works and why, so it's well worth your time to read their advice.

John

[Geoff]

Using golf cart 6v batteries, I have to use arrangement #2. Except I run two grounds to the frame of the bus, and get my positive off the two positives at the front.  I use a 3/4" thick jumper cable to connect the positive and negative posts, so my design would please the author of that article.

--Geoff

[JT4SC]

I use a Black and Decker battery maintainer I bought from HD - $30 each.  I have one set up for the house batteries, 1 for the gen battery and 2 for the 2 8D bus batteries.  They charge at 1.5 amps, which is below a trickle charge and seems to give my batteries a good "deep charge".  The chargers automatically shut down when the batts are fully charged, restarts as needed.