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When should one consider a battery tender?

If you use your motorcycle regularly, you do not need to use any charger. Only if the drain current is such that your breaks between rides drains the battery to say 12.6 V would you need a battery maintainer.

I can only speak for my BMW and my Odyssey battery.

The battery is marked to charge it at 14.4 to 14.7 volts, and float it at 13.5 volts.

The alternator on the bike puts out 13.7 volts max. On a Fluke. Both the Clymer and the Haynes manuals say anything between 13 and 14 volts is fine.

Soooooooo........ Riding the bike daily, which I do, does not charge the battery to Odyssey specs. My Midtronics conductance tester confirms this.

For practical purposes, the bike starts fine, and the lights get brighter when I rev the engine, and the red light never comes on. But, I believe Odyssey's recommendation as to charging voltage is the way to get best service and longest life.

The only way to get the recommended voltage into the battery is with an aux charger, unless someone knows how to increase the BMW charging voltage.

Odyssey's OMAX-6A-1B charges at 14.7 volts, and floats at 13.6.

The Battery Tender Plus, 021-028 has a charging voltage of 14.6 V and a float charge of 13.3 V.
 
The alternator on the bike puts out 13.7 volts max. On a Fluke. Both the Clymer and the Haynes manuals say anything between 13 and 14 volts is fine.

That is far too low. There is something wrong with your regulator or your alternator (bad diode?) or you are not reading the voltage at the battery.

And Clymer is full of you know what if they claim that.

My voltage at the battery is 14.2V to 14.3V while cruising on my oilhead.

I personally don't have much use for VRLA batteries simply because they do not outperform my flooded lead acid batteries, which by the way, I can maintain. VRLA batteries have their advantages such as lower internal resistance and therefore higher CCA, but what do I need the latter for when I am not operating at that temperature spec (0F/-18C I think it is). As for VRLA batteries having a much lower self discharge rate, thats all fine if the battery is stored off the bike, but the on-bike drains are so much higher, that the self discharge rate is of no importance.

The CTEK has3300 a cold weather/specialty battery mode at 14.7V.
 
That is far too low. There is something wrong with your regulator or your alternator (bad diode?) or you are not reading the voltage at the battery.

Yes, they were read at the battery. Perhaps I will use this as an excuse to replace the alternator with the higher wattage unit, with the hope that the later one will charge at a higher voltage.

And Clymer is full of you know what if they claim that.

Both Clymer and Haynes copy factory material, (and said the same thing) but I really don't know what BMW says. I can't believe BMW would be so imprecise as 13 to 14 volts.

My voltage at the battery is 14.2V to 14.3V while cruising on my oilhead.

That is still a little low for what is marked on the Odyssey.

I personally don't have much use for VRLA batteries simply because they do not outperform my flooded lead acid batteries, which by the way, I can maintain. VRLA batteries have their advantages such as lower internal resistance and therefore higher CCA, but what do I need the latter for when I am not operating at that temperature spec (0F/-18C I think it is). As for VRLA batteries having a much lower self discharge rate, thats all fine if the battery is stored off the bike, but the on-bike drains are so much higher, that the self discharge rate is of no importance.

Yeah, I think my next battery will be a regular flooded lead battery. Of course, some of this depends on the life of the present Odyssey.

The CTEK has3300 a cold weather/specialty battery mode at 14.7V.

Thanks for the tip. I'll look into it. Do you know where it is made? Both the Battery Tender Plus and the Odyssey charger (which appears identical to a Schumacher SC600A) are Chinese, with the usual issues.

I think Battery Tender actually makes money off their warranty, with the "Service Charges" they have. That is quite a business model, sell a product with the implied reliability of a ten year guarantee, then charge for the warranty service when it fails. My last BT never performed as advertised.
 
Yes, they were read at the battery. Perhaps I will use this as an excuse to replace the alternator with the higher wattage unit, with the hope that the later one will charge at a higher voltage.

If you have an oilhead, it already has a high output alternator. The one on my GS Adventure is 50A x 14V = 700W as listed in the specs. Other or older oilheads may be a little less.

What are you running that you draw more than 700W?


That is still a little low (14.2V to 14.3V) for what is marked on the Odyssey.

Of course. That OEM alternator with the supplied voltage regulator was never chosen for an Odyssey battery.

You do realize that there are many various voltage regulators available for your alternator, each with a different voltage setting.

Yeah, I think my next battery will be a regular flooded lead battery. Of course, some of this depends on the life of the present Odyssey.

Hold on, not so fast.

The reason why BMW installed a VRLA type battery are a few, one being due to the location of the battery. 1) They do not require topping up, simply because you can't. But if charged correctly on and off the bike, they should not gas and therefore water loss is very minimal. 2) They do not require an overflow/vent. If you install a FLA battery, then you will need to route a vent hose. Personally, I vent the end of the vent hose through the cap of a small 50 ml plastic jar with a small pin-hole in the cap for venting. You can place cotton padding with baking soda in the jar. This prevent droplets of acid hitting your frame/wheels, etc.

BTW, a buyer for Costco that I met no longer buys Odyssey batteries. They had to many issues with them. Probably due to the charging systems on vehicles and battery chargers.


Thanks for the tip. I'll look into it. Do you know where it is made?

Like everything else, most likely China.

CTEK

They have a nice assortment of add-on accessories.
 
If you have an oilhead, it already has a high output alternator.

My 92 K75 has the low output 460W alternator. I have a later, higher output 700W version, but have not installed it yet. I wonder if it has a higher charging voltage.


You do realize that there are many various voltage regulators available for your alternator, each with a different voltage setting.

No, I didn't. Thanks for the tip. Both of my two closest dealers are also unaware, as I have asked them specifically.

The online fiche for my bike shows only one regulator, a 12311459286, with no voltage stated. I would appreciate any further info on a higher charging voltage. Are these aftermarket, or what? The fiche for the later models with the high output alternator also show only one part number, with no mention made of the charging voltage.

Like everything else, most likely China.

Waaah.
 
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My 92 K75 has the low output 460W alternator. I have a later, higher output 700W version, but have not installed it yet. I wonder if it has a higher charging voltage.

Even the old one is quite a bit. I wonder what riders are running to need so much? I bet I'm hardly tapping into my available 700W, even if I have my Hella FF50s switched on.

The voltage regulator is chosen for the purpose (how it is used and battery type, for example), be it a small or large wattage alternator. Voltage regulators also come with various temperature compensation curves.


No, I didn't. Thanks for the tip. Both of my two closest dealers are also unaware, as I have asked them specifically.

The online fiche for my bike shows only one regulator, a 12311459286, with no voltage stated. I would appreciate any further info on a higher charging voltage. Are these aftermarket, or what? The fiche for the later models with the high output alternator also show only one part number, with no mention made of the charging voltage.

That appears to be the BMW part number. You are looking for the Bosch, Valeo or manufacturer's part number that is usually printed on the voltage regulator. From there, you can get the actual specs of the voltage regulator.

They can be OEM or aftermarket.

For example, here are a bunch of voltage regulators with various cut-off voltages. Its a matter of finding one that physically fits the alternator.

I have a paper listing of Bosch voltage regulators that I got off the net, but I can't find the site at the moment. :banghead
 
here are a bunch of voltage regulators with various cut-off voltages.


Its a matter of finding one that physically fits the alternator.


Looks good. Now, I gotta plan some down time to pull the old reg out, take some measurements and make a drawing, and then put it back together so I can ride it while I wait for the new reg to come.

A quick look makes me think the old 460 watt gen might be easier to upgrade than the 700 watt one.

I have a paper listing of Bosch voltage regulators that I got off the net, but I can't find the site at the moment. :banghead

Boy, that would be super if it becomes available. I would never need an external charger again if my alternator would alternate at the Odyssey recommended voltage. As it is, my bike gets a Fourteen-point-something charge from a car battery charger once a week, just to keep it happy.
 
Looks good. Now, I gotta plan some down time to pull the old reg out, take some measurements and make a drawing, and then put it back together so I can ride it while I wait for the new reg to come.

You'd be better off calling Bosch or Valeo with your alternator part number and asking them for a voltage regulator that meets your needs.

BTW, some VRs have a trim pot under the cover, so that you can adjust the regulating voltage.
 
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