Author Topic: Battery 12v showing 144amp but not holding charge. K100, 1986.  (Read 5423 times)

Offline ste_barrett

  • Curious
  • Posts: 3
1986 K100


Hi all, my K100 has been stood since Christmas. Not surprisingly she needed a good charge up before starting to ride again. My problem is the battery. It charges up OK and is good for a few starts but then goes flat. I put it on charge again and took it to Halfords. It read 12v and 144amps. The battery was new in Aug 2014 so almost 3 years old. What would you do next? New battery or something wrong with the bike not charging it up? If new battery, any recommendations?


Thanks
  • London
  • K100, and a Moto Guzzi for luck

Offline Blue

  • ^ Motobrick Curious
  • Posts: 98
Re: Battery 12v showing 144amp but not holding charge. K100, 1986.
« Reply #1 on: June 11, 2017, 10:08:32 AM »
Slow drain for months will suck it dry.  Will show voltage while being completely discharged.  Will take a charge from a charger and start, but the alternator can not overcome the damage from a complete discharge and will be unreliable.

You need a new battery and keep it on a battery tender if it is not to be started for more than 2 weeks.
  • Stovepipe Wells CA
  • 1995 K1100RS

Offline The Mighty Gryphon

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  • Posts: 6843
Re: Battery 12v showing 144amp but not holding charge. K100, 1986.
« Reply #2 on: June 11, 2017, 07:28:31 PM »
+1.   Sitting for a couple months after a slow discharge is a death sentence for a battery.

You need a new one.
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline ste_barrett

  • Curious
  • Posts: 3
Re: Battery 12v showing 144amp but not holding charge. K100, 1986.
« Reply #3 on: June 12, 2017, 07:57:17 AM »
Thanks both - any recommendations on brand etc.? I'm trying to teach myself how to look after a bike and I'm not really sure what difference the battery makes other than starting it and keeping the lights on - what else does it do? Is it worth investing in a higher cost one? What are the benefits of not getting the cheapest?
Thanks again
S
  • London
  • K100, and a Moto Guzzi for luck

Offline The Mighty Gryphon

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  • Posts: 6843
Re: Battery 12v showing 144amp but not holding charge. K100, 1986.
« Reply #4 on: June 12, 2017, 08:06:20 AM »
My only advice is to get an AGM(absorbed glass mat) battery.  They are maintenance free and don't spill acid when upended.

While many swear by the Odyssey brand, I have had good luck with Chinese batteries of the Scorpian brand.  IMHO it is more important to keep it fully charged with a good trickle charger/maintainer than to spend a lot of money.   
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline bizzaro

  • ^ SuperNatural Motobricker
  • Posts: 583
  • co pilot
Re: Battery 12v showing 144amp but not holding charge. K100, 1986.
« Reply #5 on: June 12, 2017, 02:19:59 PM »


http://www.beemerboneyard.com/westco12v20p.html


I got this one two years ago and have no complaints. Still strong so far, and I don't have a tender. I remove my battery and store it inside, and trickle charge it a few times in the offseason. Great new price!  :2thumbup: I paid the old price. Call to be sure it will fit for your bike. I have a 94K1100LT.

You probably want this one? http://www.beemerboneyard.com/westco12v30.html
  • Vermont
  • Current:1994 BMW K1100LT Previous: 1982 Yamaha virago 920,1973 Honda CB550,1976 Yamaha 650 Special
See Ya in the Twisties,
 Bizz

Offline Laitch

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Re: Battery 12v showing 144amp but not holding charge. K100, 1986.
« Reply #6 on: June 12, 2017, 02:46:27 PM »
This year I rode my bike into the shop in November. I disconnected the battery ground cable from the transmission. The coldest the shop was this winter was -5ºF, maybe. In April, I reconnected the battery. The bike started with no problem. Usually I disconnect the battery and store it in the house where it gets charged once every two months or so. I did something different last winter. I guess I was striving to be less robot and didn't even realize it.

This battery has been in the bike since I bought it five years ago.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline Martin

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  • Posts: 4475
Re: Battery 12v showing 144amp but not holding charge. K100, 1986.
« Reply #7 on: June 12, 2017, 05:35:48 PM »

I've had a good run with Deka AGM one 8 years the next one 5 years.The current non Deka ( Battery shop didn't have one) going on for 6 years.
Regards Martin.

  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline K1300S

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  • Posts: 1293
Re: Battery 12v showing 144amp but not holding charge. K100, 1986.
« Reply #8 on: June 12, 2017, 06:26:43 PM »
My only advice is to get an AGM(absorbed glass mat) battery.  They are maintenance free and don't spill acid when upended.
 

agree!
i have an Odessy PC680 in one k75s and a Batterymart Big Crank etx16L in the other one.  both work great, but the batterymart version is  cheaper...

the ETX16L is the right one for the bike. terminals on the correct sides.

http://www.batterymart.com/p-Big-Crank-ETX16L-Battery.html?gclid=CMSXpb-sudQCFRqHswodjXwOEw

i also have a Braille AGM in my vintage car.  same size as for a k bike.  it has been in there for 5 years.  still starts the high compression engine no sweat.

Project Thread "K75s Midlife Refresh"
http://www.motobrick.com/index.php/topic,7810.0.html

Offline stokester

  • ^ SuperNatural Motobricker
  • Posts: 847
Re: Battery 12v showing 144amp but not holding charge. K100, 1986.
« Reply #9 on: June 12, 2017, 09:46:21 PM »
My only advice is to get an AGM(absorbed glass mat) battery.  They are maintenance free and don't spill acid when upended.

While many swear by the Odyssey brand, I have had good luck with Chinese batteries of the Scorpian brand.  IMHO it is more important to keep it fully charged with a good trickle charger/maintainer than to spend a lot of money.
Count me in those who swear by Odyssey.  I've got one in my brick and in one of my airheads, both going strong 5+ years.



  • Yorktown Virginia
  • '94 K75S Dakar Yellow - '93 K75S Seiden Blau - '91 R100RT Bermuda Blue- '78 R100S Smoke Red

Offline ste_barrett

  • Curious
  • Posts: 3
Re: Battery 12v showing 144amp but not holding charge. K100, 1986.
« Reply #10 on: August 10, 2017, 03:00:10 PM »
Belated thanks all! :2thumbup:
  • London
  • K100, and a Moto Guzzi for luck

Offline bizzaro

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  • Posts: 583
  • co pilot
Re: Battery 12v showing 144amp but not holding charge. K100, 1986.
« Reply #11 on: August 11, 2017, 10:50:54 AM »
And the verdict is..................????????????????????? :dunno2: :dunno2:
  • Vermont
  • Current:1994 BMW K1100LT Previous: 1982 Yamaha virago 920,1973 Honda CB550,1976 Yamaha 650 Special
See Ya in the Twisties,
 Bizz

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