The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Danie on December 17, 2008, 12:05:26 PM
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I am sorry to raise another question about batteries again, but I do have to buy a new battery for my R65 this week, and I would like to raise a stupid question regarding recommended AH (Amps / Hour) ratings in general :
As far as I know , the AH (Amps per Hour) rating on batteries (i.e. 16, 16, 19, 24, etc.) is just an indication of the storage capasity of any given battery. To my mind, this only means that under similar conditions, and if there is a charging problem in the system, a 16 AH battery will get " flat" before a 24 AH battery does.
As far as I know, a 12 Volt battery does not "force" any Amps into any given system - components like the starter, lights, indicators,etc. only "pull" a certain amount of amps while in operation.
If I am correct, I would like to know about any possible reason(s) why a 24AH could not be used in a R65.
Many thanks
Danie
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I don't think there should be any problems using a 24 AH battery as long as it would physically fit. The AH rating is technically a number relating how much current can be supplied for a specific time. Theoretically 1 AH is one amp of current flowing for one hour, in a perfect world anyway.
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Danie
Using a higher AH battery is a good thing in my experience. 11 years ago I bought a new battery for my car. I chose the biggest one that would fit - 70AH instead of the specified 50AH and its still starts just fine today. I did the same with my last bike and it lasted 7 years.
AH capacity ratings are only half the story though. Cold Cranking Amps (CCA) is the number of amps a battery can deliver at 0 degrees F for 30 seconds and not drop below 7.2 volts. So a high CCA battery rating is good in cold weather. This determines if a battery has the power to start an engine and is a good indication of quality. A 24AH battery will most likely have a Higher CCA rating than a 19AH
Whatever you decide to buy the secret for long life is to keep it fully charged at all times.
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Danie,
Justin and Barry have it right on. In general, the larger AH batteries have more plate surface area and can hold more charge. This often (but not always) also means that they can deliver more peak starting current (cold cranking amperes) when you first press the starter button as the increased surface area also tends to lower the battery's internal resistance. The starters on these bikes can cause a current demand spike of as much as 150 A or more for a brief period (especially older Bosch starter motors). The closer the battery can come to supplying all the current that the starter wants without dropping the voltage too low the faster the starter can spin your engine and the more likely you'll get a good, quick start.
I think that BMW offered/spec'ed batteries for the R65 as low as 16AH as standard item, but I think that most people are much happier with higher capacity batteries - I would personally try to get one that was more than 16 AH if I could, so if you have an 18, or 22, or 24 AH, as long as it fits well in the battery box you should be OK.
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As noted the big issue is does the battery fit. Many of the larger airheads take a battery that is 4 7/8" front to back. This will not fit in the early R65s - they require a battery that is 3" front to back.
Also be aware that some batteries reverse the position of the positive and negative connections; not a big deal if you are aware of it and can make the cables reach.
If you choose to go with a maintenance free gell cell or AGM battery you may want to raise the charging voltage slightly. I have done this by putting a diode in series with the ground lead from the voltage regulator. This raises the charging voltage about 0.7 volts. YMMV but it works for me.
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Thanks for all comments.
To be honest, I have already used two 24 AH batteries in my R65 in the past, and the one which has just "died", is a 28 AH battery. The measurements of these batteries are 123mm X 184mm, and the height is 157mm.
My R65 is a 1988 monoshock, and the above mentioned batteries do fit - although it is a fairly tight fit. I bought my R65 without the battery "box", and I use a strap to keep the battery in place. I am not sure if these batteries will fit the older model R65's.
I actually raised my question, because none of the above mentioned batteries ever lasted much longer than one year. Overcharging could be the cause of an early battery"death" in the past , but I am not sure about battery quality either - a lot of junk products get dumped in our country.
Regards
Danie
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Dani
Come to think of it battery performance at 0 deg F will not be an issue in Durban at the moment. I suppose 100 deg F must be nearer the mark.
Lead acid batteries particularly the standard wet cell type do not like high temperatures. The self discharge rate increases significantly at high temperatures. I notice the difference between summer and winter even in our moderate climate. During periods of inactivity I would float charge the battery or give it a top up charge quite often. Twice a week would not be too often.
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Danie, One of the "secrets" to keeping bike batteries alive is to use a modern "trickle charger".
Here in the states we have a company that produces a "Battery Tender", for cars, and a "Battery Tender Junior" for bikes. They keep my batteries topped up (as long as I remember to attach them after rides).
My Mono has the BMW accessory outlet that the Tender plugs into. The Tender also has additional leads with clamps, as well as the auto cigarette lighter power plug. This lets me keep the charge up on the bike and my various car batteries by switching from one to the other as needed.
http://www.batterytender.com/
I shouldn't think the 24 AH is really needed unless you have heavy electric loads such as heated [refrigerated? :~) ]seat, grips, vest & lots of lights with a high percentage of slow, short trips. The Dry Cell Sealed Odyssey PC680 that many of us use is only rated for 17 AH and usually lasts for at least 3 or 4 years. It carries a two year warranty.
Of course individual experience often varies with any battery.
Just my [smiley=2cents.gif]
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Thanks for the link Ed. I recently bought a better quality tricle charger, and hopefully it will do the trick. If I am not happy with the new charger, I'll rather order a "Battery Tender".
I do like the idea of a cigarette lighter power plug as well - loose components are available at a local car sparepart shop , so perhaps I can build something up.
Barry has mentioned someting which I never knew - the self discharge rate of wet cell batteries during high temperatures. As mentioned, our local summer temperatures do get very high, and maybe I should rather look for a dry cell battery.
Anyway, I really do appreciate all comments.
Seasons Greetings
Danie
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Since you have a later monoshock R65 you should be able to fit the Odyssey PC680. I bought one this year for the R75/6 so I don't have long term reliability data yet but all the reviews have been good.
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Hi Drew
I will try to find one tomorrow, but I am not sure if Odyssey batteries are available locally - it sounds very unfamiliar to me.
Perhaps I should rather try a Bmw dealer instead of buying batteries from an ordinary battery dealer............might be very expensive though.........
Regards
Danie
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I've only had my Odyssey for a little less than a year, so all I can say is that it's stronger than my old Panasonic. (not cheap however)
Here's their web site:
http://www.odysseyfactory.com/batteries.html
Lotta good info (propaganda).
I didn't see a dealer in South Africa, but maybe you can locate one out of country that will ship to you.
(Wonder what shipping/import tax would cost from Georgia. Mine cost $136 locally, including sales tax. Weighs 15.5 pounds/ 7 kg)
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Unfortunately our currency is very weak against the US Dollar, and even weaker against other currencies like the Euro and GBP.
At the moment USD1.00 = ZAR9.81 . I am not sure about shipment cost, but if that is included, the final bill, including import tax, could easily mount up to ZAR1600.00 or more. With that amount I can buy 3 of the junk batteries (at slightly less than ZAR500.00 each)which are available locally.
Perhaps I should't complain too much..........three of the "junk" batteries should last three years as well.
Well, for the fist time I do realise that I should't be worried too much about my R65's charging system - the fact that some of the local batteries only carries a 6 mont warranty, speaks for itself.
Regards
Danie
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I'm surprised that anyone's currency is weak against our currently beat up dollar.
:-/
Is there any chance you can locate an absorbed glass mat (AGM) dry cell battery locally? They seem like they might handle your heat better than the wet cell design. -40C to 45C (-40F to 112F) normal operating range according to the Odyssey info sheet.
Good luck and keep us posted.
Ed
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Hi Ed
As far as your commend about the USA /ZAR exchange rate is concerned - according to the local newspapers, the outside world are becoming more and more aware of the challenges we are facing in our country, and this do have an effect on the value of our currency. There is a lot of uncertainty about our political future since the recent split in the ruling political party . The new ANC leadership came to power due to the support of radical groups like the South African Communist party, Trade Unions, and wild elements in the ANC Youth League . The enourmous crime rate in our country, as well as corruption by polititions in leading positions during the past few years also did not really help to improve confidence in our currency.
As far as batteries are concerned, I hoped to buy one today, but my youngest son is looking for a new car, and wanted me to go with him - so I did'nt look for a battery at all.
I will try to to locate an AGM battery, but unfortunately this will be on hold till the first week in January. My annual leave started yesterday, and I will be on my bike trip (Kawasaki) to Johannesburg on Monday.
Will keep you posted.
Seasons greetings.
Danie.
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Have a safe trip Danie. Also, good luck on finding a car for your son. Mine son is now 28 years old and I can still remember going with him to find a car. Thank God I had taught him (and his sister) to drive on his Mom's manual shift car. It made it that much easier as most of his friends were limited to automatic transmission cars. Almost a dozen years later he's still preferring the manual transmission cars.
Best Holiday wishes to you and your family.
Ed
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Danie
http://www.gruberpower.com/gruberpower/advertising/batteries/cutsheets/58-ytx20l-bs.asp
I bought one of these ( after Justin commented on them) when I thought my Odyssey had gone out.
Price is better than the Odyssey.
Have you checked for shipping to you?
Sorry if its already been discussed, I didn't read all of the thread.
I have recovered/revived my Odyssey and it is holding a full charge of 13+ volts for two weeks off the tender.
Just had a thought while writing this, if its feasable I would be happy to ship the Gruber to you at a large discount over the retail price. I have no need for two batteries. I shipped some parts to Australia and it was a bit costly. Don't know what it would be to your location till I weigh it. Just make me a offer.
I did use it a bit after all.
Troy
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Sorry about this late reply Troy - I only arrived back at home late on Monday evening.
Many thanks for your kind offer - unfortunately I will be back at work next Monday, and I do need the R65 for dayly commuting. So I do not have any choise other than to buy a local battery.
The Kawasaki has covered more than 18 000 km since the previous major service , and I do not want to push my luck any further with it's valve clearances........
Again, many thanks - I really do appreciate your offer ;)
God bless
Danie
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I eventually bought a battery - at a local bike shop ,which specializes in selling pirate parts to (what seems to be) almost all bikes on this planet.
According to their catalog, the "correct" battery for R65 models from "1984 - 1995" should be a 30AH battery (C60 -N30LA) -the same battery (according to the part list) which should be used for R80 models.
The guy at the counter probaly noticed the disbelief in my eyes - so he showed me the catalog........
the "correct" battery (according to the list) for R65 models - 1978 - 1984 is a "MS 12 - 19"
After some initial doubts, I decided to buy the (wet sell unfortunately) 30 AH battery - at the rediculous price of ZAR1048.00 . Hopefully it will keep a smile on my face until end June this year - it only carries a 6 month warranty........
Regards
Danie