Maintance free batteries?

[wraith]

Good info on a subject near to us all. The problem with antique iron is finding the right battery and then finding a way to maintain it. I am currently (no pun) using mostly "Battery Tenders" with one Harley brand charger with no complaints except that the harness with the Harley one caused a battery drain that left my new bike with no electrics. Now I just use the alligators clips in the shop.

[darrylri]

The newest Deltran chargers have a different charging program that takes gel batteries into account. Gel (AGM) batteries need a slightly higher charging rate than "wet" batteries. You should see that mentioned on the packaging.

As I said above, I have always gotten long service out of my lead-acid batteries by keeping them on a Battery Tender, and now I am starting to believe I will get equally long service out of the sealed lead acid types as well. I have one in my R51/3 that is now at least 5 years old (I got it used!), and it works great -- I can run the bike all day long with the headlight on, and there's no change in intensity when the bike is idling or even off.

Get a quality "smart" charger, set your batteries up with a harness, and keep them on the charger regularly. You will save a lot more money than the charger costs by not throwing away your batteries every couple years.

[Robert Luland]

Guys this turned out to be a great thread with a lot of info to share but no one has answered the question that I put forward. Do maintance free batteries go bad on the shelf? Bob

[PRG]

Howdy Tim,

Anything will go bad on the shelf but, besides superior charge density to LA's or Gel's, AGM's have incredible charge retention. Don't have my numbers handy but the PS series Powersonic's I use, if I recall vaguely, may loose as little as 18% in a year when a (modern EPA friendly) LA can loose as much as 80%.

But, I'll mention as the subject of exploding batteries has come up, AGM's - and even Gel's - lack to flexibility that LA's are known for, namely the ability to take poorly regulated (excessive) charge rates and good tolerance to high discharge rates. Overcharged LA's will merely boil the acid off through their numerous vents which obviously the other two lack. In the high performance battery powered model airplane arena, the limiting factor to output is heat, or in context with this discussion, heat dissipation.

Installing an AGM/Gel should be viewed as an overall charging system package upgrade rather than merely installing the battery itself. A good electronic regulator is essential to enable you to benefit from this superior technology.

[Snakeoil]

[QUOTE=Bill Golightly;74343]

What he said was that any current put into the battery when it is fully charged will cause it to "off-gas".

If a sealed batter will work in any position, including upside down, how does it "off-gas" anything? I maybe, maybe could see a pressure related leak, but I do not understand any gas loss.

Sealed batteries are another misnomer. They are actually valve regulated. They will not leak electrolyte, but if pressure rises within the battery, the valve will release the pressure and allow the gas to excape. I also believe, and I may be wrong here, that once the H2 leaves the electrolyte, it does not go back into solution, even if trapped within the battery. So whether it off-gasses freely to atmosphere, or just into the case to a pressure below the valve setting, it remains free H2 and does not reform with the other constituents to make H2SO4. So to address your point, you can have H2 leave solution and stay within the battery case. If it continues to a point of raising the pressure too high, it will then escape to atmosphere.

And to make sure we all understand where the gas is coming from, when you put current into the battery, it causes a chemical reaction to occur that changes the internal chemical makeup within the battery that was caused by discharging the battery. When you turn your lights on, you start a reaction within the battery. Charging reverses that reaction to ready the battery for the next discharge. When the battery is fully charged and current is still put into the battery, it causes the electrolyte to boil, for lack of a better term. Just like boiling water with heat, gasses are released. That is where the H2 comes from. This is why the instructions on jumper cables tell you to connect the ground away from the battery. It is possible that H2 is present in the battery case and could ignite if the ground arcs when connected. On a regular Lead-Acid battery you replenish the lost H2 by adding water to the battery. You cannot add water to a VRSLA battery so keeping H2 loss to a minimum is preferred.

Also keep in mind that the battery electrolyte in these sealed batteries is not liquid. It is either in a gel form or absorbed in fiberglass mat. So there is nothing to spill. If you put a pinhole in a cup of jello, it sure won't run out.

Most of the battery descriptions I've read for Gel and AGM batteries recommend that they not be used in an inverted position. You can turn them over, but you should not leave them there. My guess is that in a Gel battery, the gel could impede the valve from working properly. As for AGMs there might be a possibility that some electrolyte will escape from the mat and again place a barrier between the H2 and the valve if the battery is inverted. These are educated guesses on my part.

When they tell you that the battery can be used in various positions, I believe there is still a preferred position, which is upright. Things like camcorders, back in the day of giant cameras with huge battery drains all used VRSLA batteries. You could turn the camera on its side, upside down and such, but you were not expected to store the camera upside down. Also, in many of the applications for VRSLA batteries, there is no on-board charger with constant charging involved. Normally you put the device on charge and then take it off. So the odds of it being upside down while charging is kinda slim and may even be impossible if they designed the device and charging arrangement correctly. So no risk of gel blocking the valve. Why doesn't the gel ooze out the valve? I'm sure that the valve is designed to assure no leakage of anything but gas. They can do this because H2 is molecularly very small (you are making me get technical here so you brought this on yourself :-P) so a membrane can be placed over the valve that will let the H2 escape and nothing else. This is how Gortex works. It lets water vapor escape, but won't let liquid water in. Now that I think about this as I type, I'm very sure such a membrane is involved in the valve design which would make the battery 100% leak free from an electrolyte point of view. So I think that the reason they don't want you to run the battery inverted is because the gel could become a block to H2 getting out of the valve and the battery could crack from pressure, or worse, explode.

For a motorcycle application, a "sealed" battery should offer no risk of leaking unless you install it in such a way that it will crack or be worn thru. My friend built two stunt planes (a Pitts and a Christen Eagle for those who might care) and used gel batteries in both because the plane was rarely flying horizontally. He never had a leak. And we are talking about G's trying to force stuff like gel out of any potential leak path.

If a normal non-sealed Lead-Acid battery explodes as someone described, it is a safe bet that the vents were either blocked by accident or intentionally. Since the generator/alternator is always running, and if the regulator is not adjusted right, it is possible to generate enough H2 to burst the case.

I'll add one more point, because I know somebody will ask this. If batteries off-gas H2 while charging in your car, why aren't cars exploding from trapped H2 under the hood? First, if the regulator is working right, there should be little if any off-gassing. This is confirmed by how infrequently you need to top up your electrolyte with distilled water. Secondly, H2 dissapates very quickly in air. So there is very little risk of an H2 explosion unless it is confined in a container, like a battery. And even then, you need the correct amount of O2 for an explosion to occur. If you remember the old newsreel footage, the Hindenburg did not explode, it just burned violently.

[D.Mac]

Trapped H2 gas

I used to leave a battery tender on all the time on my old Triumph, as it seems to help make-up for the deficiencies of a Lucas charging system. A couple of winters ago, I had not had the bike out for several months, and noticed some corrosion on the polished aluminum parts after removing the "bike cover" (old bedsheets). Apparently enough offgas was being trapped under this cover to cause light corrosion. Something to think about, damaging to the bike and maybe even dangerous. Now I just leave the charger on untill it indicates charged.
Doug.

[s/l]

Service Free batteries

Gentlemen,

One last item regarding service free batteries, when they go dead and
are sucessfully recharged, the new capacity of the battery is 80% of what
it was before it went dead... Not a big deal on bikes without electric starters.
A big deal on those with electric legs. After the 3rd time the battery goes
dead and is recharged, it's capacity is less than 50%... Ok, 1/2 the cold cranking amps. Got it?

Jel cell batteries also have an interesting story when allowed to discharge
below 50% of new voltage. You have to charge them at a very low rate for
DAYS to trick them into recharging. Lots of jel cell (Optima) batteries were
junked before the recharging method was figured out.

Wet cell batteries make a big mess. No matter how they are treated.
And the biggest enemy of a wet battery is vibration. And, placing a charged
battery on cement will NOT make it discharge any faster that putting it on
a wooden bench.

I think this is all correct. I like maintence free batteries because they are
cheaper than the gel cells and seem to give just as good a service life. Just
don't puncture them.

FYI, S/L

[Robert Luland]

Boys I think this means I’m not buying the battery with the half inch of dust on it! Bob And Katie the super beagle.

[michiganmike]

I'll try to give a simple answer to your thoughts about the Sears/K-mart thing.
When K-mart filed Chapter 11, they brought in a guy, Lambert, who's specialty was turning around a failing business and then selling it off. He closed a lot of K-Mart stores and cut costs, but the stock still fell to really cheap prices.....at the lowest prices, he bought controlling interest in K-Mart and put his people on the board. At the same time he had been buying up stock in Sears and eventually had controlling interest in Sears, eventually "merging" the two into the new Sears Holdings Corporation.
That's why you see Craftsman items at K-Mart. I've worked for Sears 15 years.