"Battery Tender" questions

[BCKRider]

I seem to remember that if you use a "Battery Tender" that plugging it in to a winter stored bike for a couple days a month is just as good as leaving it continually plugged in. The only current draw on my bike is the clock. Any comments? (Mine is a Battery Tender Junior.)

Last year I used the adapter that let me plug the BTJ into the BMW receptacles and it worked perfectly. This fall I did the same, and after three days saw the same solid red light. Finally read the instructions on the charger and "solid red" means "you are not charging the battery." Hmmm. The fuze is good. It would seem that either the connecting cable or the internal wiring of the BMW plug has a fault, but both seem improbable. Any ideas, or exactly how to check?

I DID solve the charging problem by using the little "alligator" connections on the positive battery pole and the ground bolt, both on the left side of the bike.

My electric jacket wiring is now directly connected to the battery so guess I haven't used the BMW sockets for awhile.

[BMW Triumphant]

My new bike came with a dealer installed pigtail connected to the battery with an SAE connector to accommodate a battery tender unit. I did not request this and only found out about it when I took a pigtail in with me at the 1000 km service. When I asked them to attach it, they showed me their standard item already installed.

I have the Sr unit that has a storage mode - Jr probably does too. Just leave it connected all winter.

[AKsuited]

Last year I used the adapter that let me plug the BTJ into the BMW receptacles and it worked perfectly. This fall I did the same, and after three days saw the same solid red light. Finally read the instructions on the charger and "solid red" means "you are not charging the battery." Hmmm. The fuze is good. It would seem that either the connecting cable or the internal wiring of the BMW plug has a fault, but both seem improbable. Any ideas, or exactly how to check?

Okay, just to cover all the bases, you are connecting to the BMW socket first, and then plugging in the charger? It won't charge if you don't hook it up in the correct order.

Harry

[Peter_Krynicki]

FWIW I doubt that the junior does as good a job as its bigger brother. I've plugged a bike into a junior until it goes green and the bike still wouldn't start, hardly turning over. Then plugged in the bigger one and after going to green the bike turned over strongly and started.

[PGlaves]

FWIW I doubt that the junior does as good a job as its bigger brother. I've plugged a bike into a junior until it goes green and the bike still wouldn't start, hardly turning over. Then plugged in the bigger one and after going to green the bike turned over strongly and started.

As I type I have 6 bikes plugged into BT Junior chargers. I have never had an issue with them keeping a battery charged if the battery was in decent condition.

If the battery is OK but in a very discharged state it will take time because the amperage output isn't very high but I've not had an issue with them as maintenance chargers.

Mine are all on outlets on a single switch so I can conveniently turn them off or on. They can stay on all the time, but 24 hours every 3 weeks or so is fine unless your bike has a lot of parasitic drain. Then 24 hours every couple of weeks out to do it.

[lionheart33]

I have a Jr. When I use it the pattern is always the same, regardless of how long I have ridden or conditions in my garage. I get a blinking green for a few minutes and then a solid green. When I start my bike up after using it there is no difference than on the occasions when I don't use it. I ride year round and rarely go more than a week without riding. I replaced the original battery with an Odessy. I wonder if the Tender Jr. is actually doing anything.

Will a long enough ride result in a fully charged battery?

[BCKRider]

Okay, just to cover all the bases, you are connecting to the BMW socket first, and then plugging in the charger? It won't charge if you don't hook it up in the correct order.

Harry

Yes, I plug into the bike first before plugging the charger into the extension cord. Since I was able to work around it and don't really need the BMW outlets, guess I simply won't worry about whether the final bit of cord from the BT or the internal wiring is bad, though if anybody can tell me how to check...

Thanks, Paul, for the advice on frequency of charging stored bikes.

[PGlaves]

I want to add a comment to what I wrote earlier. It seems that Odyssey says that their batteries required a much higher amperage to "charge" a discharged battery than most other battery types available for motorcycles. For wet lead acid the rule of thumb is to not use a charger with an amp output higher than 10% of the amp/hour rating of the battery. So for most of our batteries not over two amps. The same seems true for most VRLA (valve regulated lead acid) batteries of the AGM and Gel variety used in BMWs.

Odyssey talks in terms of 6 to 8 amps to "charge" a discharged battery, and I've read that they have said 1 or 2 amps won't do it.

So, a Tender, or Tender Jr. will keep it charged more or less, but won't really bring it back if you draw an Odyssey way down. It takes a bigger charger in this case.

[jaherbst]

I want to add that keeping a wet lead acid battery plugged into a battery tender will dissapate the fluid and dry the battery out over a period of time. I have experianced this many times on my collector bikes. I am not sure of the effect of leaving a Battery Tender connected for long periods of time with a sealed gellcell or glass battery. I never leave a Battery tender hooked up for more than 24 hrs because of this. I have also ruined large batteries in airplanes and motorhomes because of this. You must monitor the acid level frequently and not let it dissapate if it is a wet battery.
A small amout of boiling always takes place when charging hence the acid/fluid depletion.

Just installed a new Odyssey 680-P in my RT. What a difference in starting. The Odyssey has 225CCA (cold cranking amps) compared with about 125 on the OEM. Was not a perfect fit but added about 1/3 inch foam under the mounting strap (only) and it fits perfectly.

I will have to look into the remark Paul made about the higher amp charging on the Odyssey for a deep charge.

Jack

[R1100RT]

I have Odyssey 680s in a 1998 R1100 RT and 2005 K 1200 LT. I have a Deltran Tender Junior and Tender Plus. If your Odyssey battery falls below 6.5 volts, you will need a bigger charge than what the Tenders will give you. Some places recommend connecting a parallel battery and then charging. I found that charging with a 10 amp charger for a cycle worked well. After bringing the battery above the 6.5 volt reading the Tenders work well. The Tenders should give you volt readings above 12 volts after they go into float mode.

I use the Tender Junior on the RT once a month for 24 hours and leave the Tender Plus plugged into the LT. The LT will drain the battery. I have have liked the ownership experiences I have had with Odyssey batteries.

Dean Kohlmeyer
Garner, IA
1998 R1100 RT Over 103,000 miles
2005 K1200 LT

[40427]

I have the Battery Tender JR. model and is has been used on many bikes for many years now.
My standard procedure when i get home from any ride is; turn off fuel taps, place bike on center stand, plug in the Batt Tender .

With this fairly new to me 1985 R80 the light stays on red for a few minutes to a few hours , goes green and the bike is always ready.

On other bikes it was the same only less time on red.

[kantuckid]

I hooked my regular battery tender up to a deep cell RV battery in my shop a few months ago and it stayed red for like ~ 2 months then turned green just the other day. Meanwhile I had been topping off with distilled water every now & then. Apparently, over time it finally got to a full charge. On my bike , it is a few days to go green. My CTEK 3300 only takes a few days to fully charge a deep cell.

[GeorgeR1200RT]

When I bought my 2000 K1200LT, I also got a Battery Tender. The dealer told me to use the plug outlet by my left knee, not the one on the top case. The top case plug only worked when the bike was running.

If you have more than one plug on your model, that may be the problem.

[GlobalRider]

I seem to remember that if you use a "Battery Tender" that plugging it in to a winter stored bike for a couple days a month is just as good as leaving it continually plugged in. The only current draw on my bike is the clock. Any comments? (Mine is a Battery Tender Junior.)

There are two thoughts on this that battery charger/maintainers use.

Some will enter and remain in a float/maintain mode after reaching a full charge.

Others will go through the bulk and absorption stages over and over again. They shut off when the battery is fully charged and when the battery self discharges to about 12.6V, the charger will re-initiate the charge sequence.

My personal opinion based on experience and testing at work is that the latter is a better method for long battery life.

NOTE: if there is one thing battery charger manufacturers are good at, it is the info they have on the outside of their packaging, half-truths at best.

I just tested a popular and well known charger at work. Either it is defective, or their advertizing is pure BS. I will bring my other unit in to work to see how it measures up. I have a data logger hooked up and am monitoring the voltage and current during all phases. The battery is new and not the issue.

It would seem that either the connecting cable or the internal wiring of the BMW plug has a fault, but both seem improbable. Any ideas, or exactly how to check?

Get a DMM and start troubleshooting.

[GlobalRider]

Will a long enough ride result in a fully charged battery?

It will IF the voltage regulator within the alternator is picked/set correctly by the manufacturer.

Battery life also depends on the charging system of your vehicle, not just the battery charger/maintained while it is parked.