6v battery problems

[captainkf]

I have 8 6v batteries for the house system and 2 8D's for the starting system. I know some might think this is a bit overkill. They cost me nothing though, so I thought why not? I tested them all before putting them in. They were not perfect but they held a reasonable amount of charge. Well, things have changed. They are not able to hold a whole lot anymore but I don't want to junk them. I have read about people emptying them, flushing with distilled h20, they refilling and charging. Being such beefy batteries I have read they can handle it. I have topped them up, I use a very nice 3 stage charger (I have a 4 stage also, which hasn't helped much), they are clean, I use 1/0 welding cable with soldered (sp ) ends. I think my electrical system is solid.

Power control center. Ac breaker, perko dc power source selector, tripp 750 watt pure sine inverter, motomaster 1200 watt inverter.

http://www.skoolie.net/gallery2/v/Skooli ... 1.JPG.html

You can view the batteries here. This is the pic after installation. They haven't changed asthetically.

http://www.skoolie.net/gallery2/v/Skooli ... 7.JPG.html

Am I doing somthing wrong? Is it possible that one pair might be shot taking out the rest? How do I test for this?

So many questions, I hope someone (or many) has the expertise to assist.

I look forward to your creative reply's as per usual.

-Richard

[pervy2u]

I'm no expert on batteries. What I do know is in an electric golf cart if you have one battery go bad the others will suffer. Buy yourself a battery hydrometer (gizmo with the floating balls) and check every cell. If it gets more complicated than that I'm sunk!

Larry

[1964_Superior_Skoolie]

Richard,
I have to ask – when you drained the batteries did you completely drain them? If so, did you replace the acid? Ages ago when I used to sell batteries they used to have to be filled with acid first before you sold them and then charged up. With the new sealed batteries that’s not required anymore. Typically if a battery goes bad it’s because there’s a short between one of the cells. I used to use a hydrometer like Larry mentions but have found that a tester that can put a load on the battery works much better. Most car parts suppliers have these and will probably test your battery for free.
If you didn’t put new acid back in the batteries then you will need to buy some and then hopefully the batteries will work.
Just so you know - the reason you want to put distilled water in a battery is because most tap water has mineral deposits and this is the main reason for shorts. A deep cell battery gets around this by lifting the cells up more so there is more room for mineral deposits.
Hope this helps.
Ken

[the_experience03]

X2 on needing acid. Lead acid batteries require lead and acid. The water alone won't do it. When you add the distilled water you are actually just replacing water that has been evaporated off and rediluting the acid while making sure the plates remain covered.

I have heard abouf flushing the batteries out, but I think that is probably some sort of an oldtimer myth or legend. I would think that tipping the batteries upside down and the associated shaking would do more to DAMAGE the plates than help anything. If the batteries are old and tired, that sort of vibration is likely to start breaking the plates up. While it might be helpful to get that crud off the bottom of the cells, unless it is shorting something out, I'd leave it alone.

One bad battery will affect the others as the bank will only be as strong as the weakest battery. On top of that, if one is not putting out what it is rated at, one of the others miust compensate. This is why it is recommended that all batteries in a bank be the same age, capacity, and manufacturer. Getting them with a similar build date is just an added bonus.

I would take your battereis to a place with a carbon pile load tester. These will emulate a serious load such as that of a starter on a cold day or a power inverter starting a large device. The smaller testers are better than nothing, but often a battery is capable of outputing full voltage and might even maintain it's rated output long enough for them to call it a good battery whereas a carbon pile load tester is going to let the battery know you're really talking to it by putting a serious load on it. I know Batteries Plus will test the batteries for free for you if you have one nearby and they use the carbon pile load testers.

Your wiring looks really nice! Someday maybe I'll take the time to do that someday. I've never seen the blue anticorrosion spray, only the red, assuming that's what that stuff is on the terminals. I do see that you have several different kinds of batteries though (I can understand the price thing) and I think that might be part of your trouble. The easiest thing to do since those things are so heavy is to just drive the bus somewhere to have them tested. Be aware that you will have to break all the connections between the batteries for it to work accurately.

BTW....unless you really aren't planning on using the bus for some time, I would consider buying batteries now if you can. The price on lead has been skyrocketing like all metals and is only poised to go up so the sooner you buy batteries, they cheaper they will be atleast for the next 6-12 months I predict.

[Les Lampman]

Hi Richard,

There may be nothing wrong per se. Batteries have a finite life (even if they just sit there) and some of yours might have hit that point. It could very well be that just one (or more) of your batteries is kaput and that will take the system voltage down. And/or they won't sustain a load any more.

You can take the specific gravity of each cell, you can get the voltage from each battery (they each have to be isolated for this to work), and you can have them load tested. Any or all three ought to point out the faulty battery (or batteries).

Also, even with a good 3-stage charger if the batteries are different brands, capacities and ages one of more may get undercharged or over charged (and either situation will "kill" the battery). The charger can only sense the overall bank voltage and can't make allowances for any individual battery. It's expensive to have all the batteries match and I'm not advocating that it has to be done; only that you're likely to have to replace some batteries sooner than others in a mixed lot.

[paul iossi]

has anyone ever checked out industriul batteries like for a forklift? i know that they come in different sizes and voltages malso that individual cells can be serviced/replaced. i have never inquired about sizes that would be useable in a coach.

[the_experience03]

Funny you should say that....I was checking out 12V170S batteries at work today which are the same size as an L16 Trojan and comes out at 12 volts and 170 amp hours with a price of roughly $170 IIRC. I also checked out some 6 volts of the same size. What it boiled down to was the per amp hour price was slightly higher with the larger batteries, but I would need a smaller footprint and less other junk like terminals an interconnect wires than with a set of regular GC2 golf cart batteries. Still, the more I look at my options (and I have options at work....), the more I like the $60 6 volt GC2 golf cart batteries, especially for my use. If I were fulltiming or staying somewhere for more than say 48 hours without a means of recharging my batteries, I certainly would look into the forklift batteries. It all comes down to usage and how thick your wallet is.

[paul iossi]

Does anyone else remember the old jumpstart setups that used a small horizontal engine to turn 12v delcotron alternators that were switchable parralell/series for 12/24v starting vehicles?
Could a setup like that be fabbed up with a good muffler and used to maintain a battery pack? IIRC the service truck i used had a 16hp briggs with 4 70A self regulating delco's,paralalled in pairs and then could be series,d to light something up or start big trucks, it also had 2 sets of cables that worked @ 12V

[the_experience03]

For sometime I've been looking into a similar (I think) setup. I have an old Crapsman tractor with a 28 ci Briggs vertical shaft engine (12 hp) that I would like to mount under the bus with a 12si GM alternator. I would run the electric start into the bus along with a toggle switch that would switch on the 12 volt field voltage so I could set it to "freewheel." I figure I could then put an insulated box around the set up and use a set of electric fans from a front wheel drive car to draw air through the box with a long pipe and a big muffler to quiet the thing down. My only concern with the idea is that alternators are not designed to output their rated voltage for long periods of time. Like most things electric they have a duty cycle and I'm not sure how much an alternator would appreciate the kind of a draw a big inverter might put on it. I also know that the engine would have to be geared so it could turn that alternator at or just above idle to make it somewhat fuel efficient. On the plus side, a 12 horse would have more than enough power to turn a 100+ amp alternator at full output.

I just ran out of time last year to build the setup. When I actually get a chance to do it, I'll post my results. Maybe someone in a more temperate climate will try it first and post results (and errors or revisions ) before I do it. It is an interesting idea, no doubt.

[Les Lampman]

I think you'll find this link interesting at Ample Power. Same idea on a grander scale.

The alternator in your setup would work fine with an external regulator that kept if from putting out full amps all the time so it didn't die.

Sounds like a fun project.

[Demonknight]

http://theepicenter.com/tow02077.html

has the same basic idea I belive...this is the one I keep looking at (i have a crapsman 5hp outside)

[captainkf]

Well thanks for the info. I have been thinking about getting a load tester as they can be bought at princess auto for about $25. They just don't do 6v so it seemed to defeat the purpose. I have tried a couple of digital multimeter's, but they did not seem able to determine enough consistency to be usefull. A hydrometer is an option.

I have not drained and refilled yet, I am just curious about the process. I am inquiring if anyone out there has personal experience with it.

Using only distilled water because of mineral deposits is somthing I am familiar with as my cigar humidors operate on the same principal.

Mixing mulitiple brands of unkown length was/is a gamble. They are all 6v as the 8d's are not attached to the house bank. They may have hit the wall and are time to be recycled. They seem to charge up, they just don't hold a full charge for too long. They drop down to 12.8 volts after a full charge after a day or so. The battery specialists (the suppliers @ the RV dealership I worked briefly at) had said that this was still a good resting charge for older 6v and were still usable. I can still get 4 - 5 days with out charging, so I am not tossing them yet. I am looking at ways to restore them.

I have never deep cycled them below 11.2 volts, is this a problem?

Thanks all!

-Richard

[Les Lampman]

Hi Richard,

If the resting voltage of your battery bank is 12.8v you're right on the money for a fully charged battery; it doesn't get any better than that. The only way they should have a higher voltage is if they're being charged or just came off the charger.

50% discharged is about 12.1 volts and 10.5 volts is generally considered "dead". 11.2 volts is a pretty deep discharge but if they're true deep cycle batteries they should handle that but they do have a finite number of "cycles" they can go through.

It doesn't sound to me like you've really got a problem at all unless with a known light load (say at the 20-hour discharge rate) they die off too quickly or with a really heavy load they all but give up immediately. Otherwise it sounds like they're in fine shape.

[paul iossi]

look for a good hydrometer, the kind with the big bulb and not just 4 or 5 balls, a good hydrometer will also have a thermometer/(temp. compensated), then go get a plastic welding rod container to store it in. also flush it with clean h20 before storing it.

[the_experience03]

Originally Posted by Les Lampman

It doesn't sound to me like you've really got a problem at all unless with a known light load (say at the 20-hour discharge rate) they die off too quickly or with a really heavy load they all but give up immediately. Otherwise it sounds like they're in fine shape.

That's what I would think too. That's why I suggested a good true load test. All to often at work I see batteries that show plenty of resting voltage (not just a surface charge) but will fail as soon as we put even a 200 cca load on them.

I've also seen plenty of people try and make warranty claims because they can't get the voltage up to where they think it should be, but at 12.4 volts they might test out to 800 cca sustained for 15 seconds on a 500 cca battery.

So much science and so much black magic in this battery business.....

[captainkf]

Well, thanks all. It's good to hear that I am overly concerned about my batteries and that they are in decent shape. I would prefer not to dump $600 worth of batteries is I can avoid it. After christmas I will look into diagnostic equipment.

-Richard