hot battery

[95SKarsten]

Discovered that my new to me '95 K75S has wiring harness for battery tender, only the positive wire was attached to positive battery post, the negative wire was just laying under the seat.Not knowing that at the time, I plugged my battery tender plus into the harness for several hours since I had not ridden the bike for several days. After changing brake fluid and fixing a few other minor things, I attempted to start the bike, nothing, won't start, note even turn over. Did some digging and discovered that the negative from the battery tender was not attached to anything and the battery was extremely hot to the touch. I undid all negative wires from the battery and gonna let it cool down.Plan on hooking everything back up to battery, once it has cooled down, was the missing negative from the charger the reason for the hot battery or is there anything else I need to check? There are no blown fuses. Thanks for all pointers

[kennybobby]

Is it a lead-acid type battery, or some Lithium variety?

do you have a voltmeter to measure the at-rest battery voltage (all cables attached, Key OFF), and also the voltage with key to ON, kill switch to RUN ?

Was it HOT, as in too hot to touch?

[95SKarsten]

it is a lead acid battery, I think, it was almost too hot to touch, don't have a volt meter, will get one tomorrow and check.

[Laitch]

it is a lead acid battery, I think,

Find out for certain. Guessing the specs of your components is no good. Text on the case should tell you or you can Google the make and model number. Does it have caps or not?

[stokester]

What kind of battery tender do you have?

If only one lead of the battery tender connection is attached my battery tenders will flash red to tell me that the connections are not correct.

[95SKarsten]

the battery is a non vented Panasonic and the battery charger is "Tender Plus"

[Laitch]

My guess for today is your tender was working because the wire was inadvertently grounded and your battery won't hold a charge. My weather forecast for tomorrow is 40% chance of showers but decreasing chance throughout the day and probably just cloudy.

[kennybobby]

i imagine Laitch is a good weatherman--of course any motorsickle rider gets good at weather over time, or they end up riding with wet shorts and boots.

If the unattached ground wire was touching the frame then charging could occur.

The BT+ can charge at up to 1.25 Amps.  It will raise the voltage in an attempt to send the maximum current into the battery until the battery voltage rises to the cutoff and then the current is reduced (trickle).

Some of the Panasonic sealed batteries require a lower regulated charging voltage than the typical flooded-cell type (e.g. 13.7 vs 14.4).  Maybe there is a setting in the BT to adjust for this? 

My guess is that the battery was somehow being over charged and the heat was generated due to lack of venting as the cells were trying to off-gas.  My second guess is that the BT cable was disconnected by the previous owner because he was aware of the lower charge voltage of the Panasonic and lack of correct regulation by the BT.

One of my project bikes has a sealed-type battery and i've noticed that the battery lamp on the instrument cluster is always slightly illuminated, which is an indication that the battery voltage is lower than the output of the alternator.  This makes sense considering the 13.7 vs 14.4 max voltage for sealed vs flooded-cell batteries.

My third guess is that some sort of alternator voltage adjustment is needed to prevent overcharging of sealed batteries on the K bikes...

[stokester]

I've got a  Panasonic LC-X1228P in my '78 Airhead and have used a Deltran Battery tender without issue for a number of years.

A good check would be to test the battery to get a good indication of its state of health.

[Martin]

If you try to start the bike with a flat battery the starter relay points can fuse together. When this happens the battery will overheat. The first time it happened to me, the bike kept cranking over very slowly. It the stopped cranking and the battery continued to overheat until it blew out the side of the battery. I was lucky I had access to water, as acid went everywhere. I have now installed a battery isolator switch in the earth lead behind the left hand side cover. It is handy when you want to work on the electrics as you can just switch it off, it also doubles as a security device as you can also remove the key.
Regards Martin.

[kennybobby]

Panasonic valve-regulated lead acid VRLA battery datasheet shows 6 to 10 year life on trickle charge for standby power applications, etc.  Charging control voltage 13.6-13.8.

[95SKarsten]

good advise Martin, will do the same

[brianhinton]

Are you talking about the SAE plug or are you talking about plugging into the accessory outlet? We always used the plug next to the lift handle and I don't recall ever using the powerlet plug [emoji848]


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[95SKarsten]

there is a wiring harness that came with my battery tender that is supposed to be installed, attached to Bike's battery, to plug the tender up to. The K 75 had that harness already installed, only the positive lead of the harness was attached to battery, not the ground (negative). So, every time I hooked up the tender to the bike, it would of course not charge the battery. What happened is that, exactly as Martin pointed out,the flat (uncharged) battery caused the relay points to fuse, which caused the battery to overheat. I verified that today, ordered new relay and battery and will have to make sure battery won't go flat again. I understand that this is not uncommon with K bikes.

[Laitch]

Good followup, Karsten! I personally rely on Martin to blow up things for my educational benefit and save me the trouble. Send him his congratulatory coconut now so he'll get it by Christmas.

[Martin]

I'd rather have profiteroles the ones with cream not custard. It is a common fault that's why I fitted the isolator.
Regards Martin.