Visual Voltmeter, Battery Tenders, and more

[Stick]

Here’s a cheap voltmeter…

Try looking at the beam your headlight sheds…works better at night, and against a light colored garage door… At an idle (about 1000rpm), your battery is actually discharging a bit. If you move the RPM up to about 3000, the light should become brighter a bit. You’re seeing a result of the voltage going from about 12V to about 13.5V. This is normal.

BTW, your DUC and most “small engine” bikes like to run up around 4000 RPM. Mine seems to smooth out at these RPM’s. My old R100RS “other brand” bike was similar. It’s voltmeter was never topped out until the bike was ridden at 3600 rpm or more. Don’t feel obligated to shift into 6th gear all the time. Many trips on my secondary-road commute to work, I rarely get it into 6th gear. These ain’t Jap. 4 cyl. bikes, and they need to be driven uniquely. Good new is that at least we never have to worry about valve float!


Battery “tenders”:
I do not place 100% faith in these. I had one (a nice Sears brand) hooked to my garden tractor, and the battery still went south. I prefer to “top up” the battery(ies) once a day using a simple trickle-charger, or one of these tenders. I do this using a 24hr. timer and it comes on once a day for 1 or 2 hours. I’ve had very good results over the years doing this…

[dug]

Originally Posted by Stick

Battery “tenders”:
I do not place 100% faith in these. I had one (a nice Sears brand) hooked to my garden tractor, and the battery still went south. I prefer to “top up” the battery(ies) once a day using a simple trickle-charger, or one of these tenders. I do this using a 24hr. timer and it comes on once a day for 1 or 2 hours. I’ve had very good results over the years doing this…

I have had great success using the actual 'Battery Tender' on several bikes. I've even resurrected a long dead car battery enough to start the engine. Battery Tenders can be left hooked up to the battery with no fear of 'boiling' it dry. I keep the rarely ridden bikes hooked up over the winter and they start just fine come spring.

[Stick]

I had a home-made trickle charger that I used for about 25 years, until I accidentally overloaded it with the interior lights of my car (left them on by mistake). Over the years, I got into the habit of using a 24 hr. timer with it—comes on once a day for about 2 hrs.

Have a BatteryMINDer for maybe 10 years now. Also a few Schumachers. Although the newer ones promise to “maintain, float charge”, etc., I’ve seen one of the Schumacher empty the water out of my bro’s. 25Ahr. 2 yr. young BMW battery. And I my garden tractor battery expired after about 5 years? Anyway, I have timers on these now, and have them do about a 2 hr. charge. On the ST2, this takes place just prior to me taking off on my normal commute.

It seems I just have better results when I use the timer. Almost 8 years from my OEM ST2 battery. Now I have a bigger (22Ahr) AGM battery.

Note that I’ve seen a couple of the Schumachers go “bad” where the lights don’t come on/cross over at the set voltages (orange for chg., green for float at 14.2 or 14.3V). So back to WallyWorld they went and I just bought a new one there.

Never a prob. with the BatteryMINDer. Although recently, I noted that with it connected, and the timer off (no 120V input), that the reverse current into it seems high, like 70mA or so. The Schumachers are a lot less drain on the battery in my “off period” (like 5mA). My home-made one had an output diode, so drain current was wayyy low, like 0.02 mA

Also note that I’ve seen the desulphation feature on the BatteryMINDer made the OEM ST2 battery look better. It seems that this feature really works. This took a long time, though, like over the course of a year. I’ve never seen another battery loose its’ white crud on the edges of the plates using other chargers.

[Ride]

I bought the Deltran Tender Plus as soon as I got my Duc and am quite pleased. I like the 1.25 amp charge and have had zero issues since keeping mine on the tender whenever it's not being ridden.

[ST4R]

I use a BatteryMINDer® Model 12248 and it works well. They key to any battery charger is to only use it when the ambient temperature is near 77F. Above 77F you need to reduce the charge voltage - below 77F you need to increase the charge voltage.

All these chargers claim to compensate for temperature... but I don't trust them. They shorten the life of your battery.

The BatteryMINDer® Model 12248 has an optional lead which monitors the actual temperature of a battery post and then adjusts the charging voltage accordingly. They call it the "at the battery temperature sensor". That's the way to do it.

Best bet is to disconnect any battery charger in the summer. They'll overcharge the battery any time the ambient temp is over 77F, and in a 100F garage I would imagine you're going to go into thermal runaway which is the death of a battery.

I use the optional temperature sensor lead on the BatteryMinder. Otherwise I'd just plug-in the charger once every couple of weeks on a nice day for a few hours.

[Gilles]

Before I moved to my current location, I was an avid diver with an underwater scooter (still have it). The scooter has a 24 AH 12 V battery that had to be charged. This same charger works great on my small 10AH x 12V on the S4R. Has a floating point charge feature that keeps the charging current steady and slows it down when near full.