The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Mainerider on April 07, 2014, 07:36:43 PM
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The '81 R65 I just bought doesn't seem to hold a charge. The seller put a new battery in it in January. I have the receipt. I charged it when I first got it and after a week or two it doesn't have enough charge to turn over the motor. I'm not riding it much but it sure doesn't seem right.
So I checked the voltage at 3000 rpms. 14 Volts. Then I disconnected the negative lead to the battery and checked the voltage between the lead and the battery. 11.9V Then I turned on the ignition: 12.1V that's not good, eh? What next?
Steven
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It sounds like your charging system is working with 14 volts at 3k. If your tests are saying that voltage drops across the battery ground strap (negative lead), I'd make sure all connections are clean and tight.
Is it a sealed battery or a conventional, flooded type? If it's flooded, you want to make sure that the electrolyte levels are good.
How high are you keeping the revs when you ride it? You're not really charging until you are consistently in the midrange. You will also drain the battery more than you can charge it if you're doing a lot of short runs and stop and go riding.
The battery shouldn't drain that quickly just sitting there (especially if it is an AGM), though the cold will reduce it's ability to discharge quickly. You could try disconnecting the battery ground and measuring current between the negative terminal and frame to make sure you don't have a constant drain on the battery even with the ignition off, such as a (very thirsty) clock or a voltmeter that is hooked up directly to the battery.
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The charging system on the airhead bikes doesn't do much charging, until you get in the 4000 rpm area .
If you are riding the bike at slower speeds than 45 mph, you're not charging the battery when you ride .
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What is the cca and amphr. rating of the new battery? It might be new but not the one you need. Check your owners manual.
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We do need more data, as has already been suggested.
I've been told it takes 15 minutes of more than stop-n-go riding to recharge the battery after a start up.
Does the battery fill the battery box?
It looks like your cables (the negative at the very least) has a LOT of resistance. They are only crimped together and can corrode where the cable is crimped to the end fitting. I'm guessing that's the problem. Was the positive lead checked as well?
That could possibly be the whole problem right there!
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Hello !
If the battery charge get lost with the bike sitting in the shed, maybe you've something eating up electricity ignition off....
With the battery well charged, and the bike turned off I would measure the leaking current. This will ascertain that there is no drain killing the battery.
I use my R65 to go to work every day. In town. around 15~20 minutes ride with the headlight on and my battery holds. I've done this for years !
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So I should have measured current, not voltage, when I had the battery disconnected. I'll check that after work today. I can check the details on the battery, too. And there aren't any straps holding it down. I'll see if I can swing by Street Cycles this afternoon and see if they have them in stock.
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Your R65 uses two flat rubber battery hold down straps. Steel pins extend perpendicular to the strap ends. These are captured in matching metal hooks formed on the battery box. Best of luck finding these at a dealership. I finally made up a pair of short bungees to secure my batteries.
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Don't buy a new battery just yet... And, if you do wind up needing one there are a couple of joints we get a 5% discount from...
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I agree with Georges. To see if your battery is being discharged overnight you need to measure any leakage current with the ignition off. There should essentially be no leakage and if there is a quick test would be to pull the relays to see if one of them is the cause.
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If you are riding the bike at slower speeds than 45 mph, you're not charging the battery when you ride .
That's what 2nd gear is for, Bob!
Your R65 uses two flat rubber battery hold down straps. Best of luck finding these at a dealership.
I did manage to order one (no thank you, just a belt is fine, suspenders would be overkill) from a dealer here in town.. the usual BMW price and service. $$ and a couple weeks later it came in.
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I've actually had good experiences so far with he local BMW dealership having everything I've asked for so far. Roundel for the tank, oil filter kit, assorted crush washers, rubber bushing for the shift lever. Everything at or below what I've seen them for online.
Steven
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If I caused some confusion I apologize. I sometimes call the negative battery cable a "ground strap." The rubber hold-down straps are good to have though... a little extra insurance against accidentally shorting the positive terminal/leads
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I went for a short ride yesterday after work. She started right up. Didn't ride much, mostly slow local roads. I stopped at the gas station to put gas in the Symba my son is learning on and afterwards the R65 wouldn't start. Just not enough juice. I put it on the charger overnight and this morning I disconnected the negative lead and put the meter to it. Only .8 mili amps. That's not enough to worry about is it?
I haven't looked up the battery info yet.
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0.8 milliamps or 800 microamps would take thousands of hours to discharge the battery so that's not a concern.
Even though the battery is almost new it sounds like it's the problem.
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Sometimes batteries just fail no matter how much love you lavish on them.
The new AGM battery in my Triumph 900 Triple was installed January 2013. March 2014, it went Tango Uniform even though it was ridden frequently and kept on a Battery Tender Jr. Vendor replaced the battery, shipped free, under a prorated warranty for only $23.00. All good now.
Luck of the draw, I'm guessing. The Stabb AGM battery in my '81 R65 is going on 4+ years and is as strong, or stronger, than when first installed. I did remove the OEM VR and replace it with a solid-state unit from Mottorrad Elektrik.
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What is the make and model of battery that you have in your R65 ??
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It's a BMW battery:
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi146.photobucket.com%2Falbums%2Fr241%2Fbauerdad%2F2014%2520pics%2F35a59761d9a3afaecc8f715b284e868f_zps0658a951.jpg&hash=94e379d41e5ae2cb76ac00232c83f89eb9eaa789)
Here's the receipt:
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi146.photobucket.com%2Falbums%2Fr241%2Fbauerdad%2F2014%2520pics%2F9f38903d29b72aaf7c8188dc8b6bd043_zps7ca7ea9e.jpg&hash=d95dbc34aee5f14878b5c53fe71276b960737d16)
So it looks like 19 amp hours.
Steven
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Have you checked the fluid level in the cells ??
Lets see if we can get the problem narrowed down a bit !!
Charge the battery with the cables disconnected until it is fully charged, disconnect the charger .
Let the battery sit for a day or so disconnected from the bikes electrical system .
Reconnect the battery cables and see what happens when you start it .
Just trying to narrow it down to the battery or the bike .
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Ok, I'll take the battery out of the bike tonight and put it on the charger. Street Cycles had the rubber battery straps in stock. It was really windy riding up there this afternoon. I'm loving the Sena SMH-5 Bluetooth communicator I just installed on my helmet.
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Be sure to check the fluid levels, it wouldn't be the first time a battery was not properly filled at the dealer before selling it .
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Fluids were good. Reading 12.45v. It's on the tender now. That's after charging last night and riding about 15 miles today, half on the highway.
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When you think you have it fully charged leave it to rest overnight and then measure the no load voltage again. 12.6V is 100% charged, 12.4V 75%, 12.2V 50%, 12.0V 25%, 11.8V Flat.
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A battery tender, may not charge the battery completly, if it is heavily dicsharged .
A battery tender is meant to keep a charged battery topped off, you may need a battery charger .
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I have also found that a seriously discharged battery sometimes will not respond to a battery tender, but needs a 'jolt' (and volt) from a proper hairy chested battery charger.
Although I do use a tender regularly when I can find it (lots of friends borrowing it).
Cheers
Rev Light
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The instructions that come with the Battery Tender Jr clearly state that the battery to be "tended" must be 80% charged for the maintainer to do its job. Also mentions it will not recover a discharged battery.
I have a larger battery charger that charges at either a 2 or 4 Amp rate. This is the go-to unit for neglected batteries before they go on the Tender Junior.
Quoting Pretty Wife, Have you read the instructions, darlin'?
My usual 'Guy-Thing' response is, I dun need no stankin' instructions. ::)
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So this is what I've got:
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi146.photobucket.com%2Falbums%2Fr241%2Fbauerdad%2F2014%2520pics%2FA5886E43-1DC2-4544-A7DD-14F4565EFE5E_zps7yqyvhig.jpg&hash=c230581c1c5e19e97b361d904534a180c333b973)
I thought the 10 amp charger would be overkill. It's not a BT jr, it's a BT Plus. I don't have the manual for it, though.
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When the charger is automatic and is limited to a specific maximum output voltage typically 14.4 volts then the amp rating may be irrelevant. The concern about oversized chargers mainly applies to the old unregulated type which are capable of 18 volts towards the end of the charge cycle.
I've used the same automatic charger for the car and the bike for over 20 years. An automatic charger is just mimicking your bikes voltage regulator. Automatic chargers also usually have a float setting at approx. 13.6 volts which is safe to leave permanently connected.
If you have any concern about a charger measure it's output voltage while it's charging the battery to make sure it's a safe voltage and check the current doesn't exceed 2 amps for a sustained period. Anyone with an AGM or Gel battery should only ever use an automatic charger as they are much less tolerant of excess charge voltage than normal wet cells.
Bottom line is the battery manufacturer will provide guidance on charge voltage and current. As long as your charger doesn't exceed the guidelines the size doesn't matter.
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So all my battery plans went out the window when I got home from work yesterday and it was 68 degrees out. It's the first time it's been above 50 and I just had to put the battery back in and go for a ride. Spring is finally here!
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi146.photobucket.com%2Falbums%2Fr241%2Fbauerdad%2F2014%2520pics%2F8CBB614B-7DF9-4E61-A5A7-C6BBC66A474D_zpsb31i7fje.jpg&hash=4b07bed4de690b39c1651bc087fe18eb9e066946)
So after a few days on the charger she started fine. And this morning I ran some errands and everything was still good. I'm away till tomorrow, I'll put the meter on it then.
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So I've still been limping along with the same battery. I charged it up last week then rode about a hundred miles on Saturday. I checked the voltage this morning - 11.3V. So I guess I'm looking for a new battery. Is the 18AH Gruber enough battery or should I go for the 22AH Staab?
Steven
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Either will work, but you'll have a little more reserve capacity with the 22A-h one. I tend to always go with the higher A-h rating battery I can, all else being equal.
Are you sure that you don't have an electrical leak (current draw) somewhere that is drawing your battery down while the bike is parked? Were you measuring 13.4V or better at the battery terminals when the engine is running at 3500 RPM?