possible charging issue

[pablosixfivezero]

I buy all my yusa batteries on ebay for about $30 and the one in my XS650 is 2 years old and still going.

[tomterrific]

Hi Pete,

I can get two bad ones but I'd have to order a new battery. The fellow that had two mikesxs batteries go bad never thought the new battery was his problem so after a year of letting his XS sit he found the battery bad and bought another from mikesxs. This new battery he bought went bad imediately but by then the poor guy knew enough to check the battery. The third battery, a replacement for the second he purchased, was sent and this is okay as far as I know. So there was a battery problem that I didn't hide from Billy/others. Was I wrong?

Do I know of any recently? What about this thread? Also, I don't know when Billy bought this battery only that it has been is service a year so I leave it up to Billy and others if I was right to bring up the battery problem. Was I wrong?

My crude XS with it's rusty case voltage regulator, adjusted, is charging up a sealed battery just fine for 3 years. The battery was given to me. I charged it up and it keeps working, yea! :^)

Tom, fixing his own bikes under a shade tree since 1967.

[pamcopete]

tom,

Well, any sealed battery is more susceptible to damage from over or undercharging. The electrolyte is super pure and the plates are very close together, much closer than a conventional battery, so they have a tendency to warp or even short out if the charging system is not working properly. As I said in my previous post, MikesXS buys his batteries from a battery manufacturer, just like any body else. We hear more about MikesXS battery failures on this site because (wait for it) we are an XS650 forum!

BillyChop mentions a 4AH battery in one of the above posts and then talks about MikesXS battery in another, so I'm not sure which battery was the subject of this thread. He also mentions that he is getting the correct voltage at 2500 RPM, but not what his voltage is at higher RPM's which is apparently when he had this failure, after a long trip, presumable at highway speeds, which is where a bad regulator will cook the battery.

Although we think of a sealed battery as being, well, sealed, it still has a vent that works to prevent the battery from blowing up if it is seriously overcharged with a high voltage. The electrolyte vents under sustained high voltage charging, but there is no way to replenish the water, so one or two cells just dry up and stop producing. The same thing can happen with a conventional battery, but we just put more water in it and keep going, not even bothering to start a thread here about it.

When the car manufacturers started putting sealed batteries in cars a few years ago, they also upgraded the charging system to the point now where there is a Microprocessor managing the charge and discharge of the battery to ensure long life.

[ShakerNorm]

I remember having the same concerns with car batteries when they came out with the sealed ones..... especially up here in the great white (and very frozen) north..... -40 isn't good for any battery, and the sealed ones failed pretty quickly for a long time.

[billychop]

Pete, not to correct you but it's a 6ah battery and probably still my original problem. I got it from Mikes but it was listed as a non-XS application battery. I had a very specific size in mind and this one had the most ah for it's size. When I replace it I will probably try and go slightly bigger, both in physical size and power. Thanks again guys

[tomterrific]

I want everyone to know I have nothing against AGM batteries. The tiny original Panasonic AGM battery lasted 13 years in my 1989 first year Miata. Now that is a good battery! Pete knows mikesxs products better than me so if he says the battery is now good then it's a good deal. However, at one time Mikesxs AGM batteries sucked and that is going to make anyone a little shy about buying one.

Tom

[pamcopete]

billychop and tomterrific,

Billy, Using a battery that is not rated for the XS650 puts the whole discussion in a different light .

Tom, again, MikesXS does not manufacture batteries and Billy's experience is not the same as the problems that MikesXS had with his source of batteries 4 years ago.

The Amp Hour rating of the battery has to match the available amps from the charging system or you will experience problems. In Billy's case, he used a 4AH battery in a system that can produce more than the 400 mA maximum charging rate (10%) for the battery so the battery failed.

Now, some qualification here. The 400 mA max is for a discharged battery. A battery is considered discharged at 10.5 volts, which this tiny battery probably experienced often sitting at a red light with everything on, including the headlight. When the bike took off when the light changed, the maximum recommended charging rate was exceeded, over and over again, so eventually the battery failed.

[tomterrific]

Thanks for the battery tech Pete. I did not know about the 10% max charging rate with AGM batteries. I did always charge my Miata AGM at the 2 amp level with my basic charger.

Pete, what you are suggesting is that 1979 and earlier XS650 should not use an AGM with the stock charging system?

Tom

[pamcopete]

Tom,

The 10% maximum charge rate is for any lead acid battery not just AGM's. The stock battery is a 14AH battery so it should not be charged at a rate higher than 1.4 Amps. Round that off to 2 Amps and it explains why the stock charging system was designed to produce only about that amount with all the electrics turned on.

The qualification here is that the battery will only draw that amount in a discharged condition. The accepted voltage for a discharged battery is 10.5 volts. The 2 Amps of extra amps from the alternator is only available at higher RPM's, so if you are sitting at a traffic light and the battery voltage goes down to 10.5, the alternator is not going to suddenly push 2 Amps through the battery when the light changes. It's a long way from idle amps to full available amps so the battery voltage is higher than 10.5 by the time the alternator is capable of producing that so the battery really never gets the maximum surplus from the alternator.

Starting out with a 4AH battery in that same scenario and it will get more than the recommended 400 mAmps almost immediately that the RPM's go above idle. If the 4AH battery was a standard "unsealed" battery, then it may just boil off a little water that the rider replaces. If you have a 4 AH AGM battery, chances are the continuous over amp charging will cause the vent to vent some water, but there is no way to refill it, so it eventually just dries up and dies. Added to that is the very thin and closely packed plates which will warp and possibly short out from the heat generated by the unneeded extra charging amps.

So, you have to match the battery size to the charging capacity. The same is true if you go the other way and install a huge battery without increasing the capacity of the charging system. People do this all the time in their cars and trucks. They install a battery the size of a refrigerator and then proceed to use the extra amps that are initially available, but now you have the situation where the battery can deliver more amps, but when it comes time to recharge the battery, the current required is greater than the surplus current available from the charging system, so the battery never really gets fully recharged and dies a slow and agonizing death by starvation. You hear people all the time saying that the giant battery in their car ain't no good because it only lasted a year.

As for using an AGM battery in a '70 to '79 XS650 with the relay type regulator, that is no different than any other regulator. You have to ensure that your charging system is working properly and not producing more than 15 Volts at the battery at highway cruise speeds.

[billychop]

Pete, again it's a 6ah battery not a 4ah. I knew I was risking it a little when I bought it, but I probably got 2500-3000 miles out it. I even did like 700 miles one weekend and had no problems whatsoever. For the first few weeks after getting the bike finished I would check the charge on the battery after returning home and it checked out. Eventually I stopped checking it, probably right about the time it started to lose charge.

[pamcopete]

Billychop,

Got it, finally.....you had to tell me twice!

A 6 AH batter is still less than half the stock 14AH so my little input is still relevant. A 6AH Battery should not suffer more than .6 AMP charging.

[xsleo]

Put a volt gauge on the bike. The led one Mike's sells will work. I put one, an analog one from Harbor Freight , $4.99, On my 75. It saved me a long push home, It might save you one too.
Leo