Hello all,

Been a while. The bikes been off the road over winter for repairs, and I've had little time to do as much, or anything that I wanted to do to it.

Anyway, apologies as I know the battery debate has been covered to death, but not in recent years - I'm hoping theres new news!

I'm looking for a battery I can either stick inside  a seat cowl (cafe racer style) or mount elsewhere as I want to free up the original battery mount location.

I've got a Varta 25Ah 220CCA brick at the moment that works "most" of the time.

What would be a Li-ion or LFP equivalent to either this battery, or a suitable one to start the K100 happily?


I don't know what the minimum CCA required is, nor the minimum Ah recommended for a K100...

Cheers

Yes, we've had lots of very recent discussion on batteries and all this has been discussed before. You just need to use the search box located on the Portal tab or the Forum tab and enter the search term [battery] or multiple terms like [battery lithium]. If you want the latest posts about this topic adding a search operator such as [date:2016] will give you all the threads started in 2016 as well as 2016 posts for threads posted earlier. In case you find that difficult here's a link...
www.k100-forum.com+date:2016&*" target="_blank" rel="nofollow">www.k100-forum.com+date:2016&*" target="_blank" rel="nofollow">https://www.google.com.au/search?q=battery&sitesearch=www.k100-forum.com&gws_rd=cr&ei=Z7jEWOnINoP28AWkubKACg#q=battery+lithium+site:www.k100-forum.com+date:2016&*

BMW originally specified a 25Ah battery for the K100. A few here like myself use a Motobatt AGM battery which is 30Ah (Motobatt don't make a smaller one that fits). Others however use batteries around 20Ah. These seem to work as ok. The only problem with lower Ah is there is not much in reserve if you run into problems.
As for CCA, I don't think there are any clear specs. My Motobatt MBTX30U is rated at 360CCA but I think you would get away with a minimum of about 240CCA. Keep in mind that the lower the specs the less reliable it will be in the long term.

As for lithium. The latest tech is LiFePo. Many here will agree that you are wasting your money on a litium battery for a K100. Aesthetically, I've seen plenty of good looking K-cafés with the battery mounted normally and they look good. There is no appreciable gain by having a lighter battery.

Cheers

just a reminder of the typical lithium battery's

as they approach discharged you get almost no indication that they are going to do that ...they just refuse to recover for another attempt at a start

at least on an old lead acid , you can hear see that the voltage is getting lower before they throw in the towel ...and they do recover fairly quickly ..well not fully but significantly enough to get a push start, and on your way again ?
by the way they don't like hot environments at all ..

Holister wrote:…
Many here will agree that you are wasting your money on a litium battery for a K100. …

Hello!

But for a caferacer it could make sense, a caferacer isn't a bike to (only to the next cafe place to showing up :-) to ride long distance.

But if you like, why not have a look in the air industry.
Super B 7800 Aircraft Battery

Cheers

My K100RS 16v with ABS is happily starting with a 14 Ah Yuasa gel battery (YTX14BS), It has about 180 CCA and needs no more. It is about a quarter of the size and weight of the 1960s technology battery that was fitted to the early Ks. BMW changed to smaller batteries with the birth of the K1100 as battery technology had moved on in the '90s.
As for Lithium, I have one in my Ducati 848 and it weighs in at 600 grams. It has no problem starting the big twin at any time. Lithium batteries have huge CCA, something like 400 for 10 seconds, but low Ah, this should not matter with the K as the alternator is big enough for any power that you need when the engine is running.
The Yuasa YTX14BS costs around €60 whereas the lithium was about €110.
There is no point in saving weight on a K as you will never feel that saving.
If you are one of those that think the original old lead acid battery is good enough then why not use old fashioned 20/50 mineral oil from the '70s, and crappy old 1970s tyres too.
Just remember that the only reason for the battery is to start the bike, after that it does nothing.

BobT wrote:My K100RS 16v with ABS is happily starting with a 14 Ah Yuasa gel battery (YTX14BS), It has about 180 CCA and needs no more.

And it would because the YTX14BS uses a 20hr rating. Work that out on a 10hr rating which most other M/C starter batteries are based on and you have well over 20Ah. Yuasa rate that battery at 12Ah@20hrs and 200cca. Other manufacturers at 220cca. Let's not confuse the issue for the OP who is trying to work out which battery is best for his machine.

Holister wrote:

BobT wrote:My K100RS 16v with ABS is happily starting with a 14 Ah Yuasa gel battery (YTX14BS), It has about 180 CCA and needs no more.

And it would because the YTX14BS uses a 20hr rating. Work that out on a 10hr rating which most other M/C starter batteries are based on and you have well over 20Ah. Yuasa rate that battery at 200cca. Other manufacturers at 220cca. Let's not confuse the issue for the OP who is trying to work out which battery is best for his machine.

I see what you are saying so the YTX14 BS will be ideal for the OP then. The Ah rating means very little on a starter battery and 200+CCA will be fine for his machine.
It would probably also fit inside his seat cowl.

Thanks for the input guys, very helpful and much appreciated. I may now end up looking at non-L-ion batteries to save cost, gel ones seem appealing due to versatility with mounting them on their sides.

However I've noticed some batteries (odessey for example) state the CCA rating and a PHCA rating. I'm aware of the difference being one is for freezing temps, the other is for 30'c temps.

However I'm still at a loss when trying to work out which rating is more relevant to me if I'm riding my bike when the outside temp is typically going to be between 2'c and 30'c - UK temperature.

If you are riding you bike then the battery is doing nothing. It only does anything when you are starting. I have used Hawker Odyssey PC680 on my Ks before. They are fantastic batteries and I have one on my microlight (4 cylinder, 4 stoke, 1400cc, 100hp). They are the same physical size as the K1100 battery which is half the physical size of the old 28/30Ah original K100 battery.
Not cheap though.

JaseYPK wrote:.....
However I'm still at a loss when trying to work out which rating is more relevant to me if I'm riding my bike when the outside temp is typically going to be between 2'c and 30'c - UK temperature.

It won't matter. CCA is measured at -18ºc.
I don't see 2-30ºc as extreme temps. Quite mild really. If you're worried, go for something with higher CCA but as BobT said above, the battery is only used for starting. After that it pretty much does nothing.
Make sure you check out the AGM batteries to.
Possibly some of the Poms from the North of UK will chime in with what they use.

As Holister says look at AGM. The Hawker is AGM and I also believe that the Yuasa YTX are AGM. 
No need for a breather pipe with AGM and you can use them on their side if you want.

The best battery you can buy for money is the AGM KungLong.
Most of the K rider in Germany use them, I also!

30£ And is much smaller than normal acid batteries


Kung Long WP18-12 12V 18Ah UPS Battery - This is an AJC Brand® Replacement



Cheers

Looking at those skinny battery terminals and the fact that it is described as a UPS battery and gives no indication of CCA, I wonder how that compares with a Yuasa? UPS systems have very different requirements to starter batteries. 
You might save the price of a tank of fuel, but is it worth it?

Bob you properly don't know the kungLong Battery, we do!
If you want other terminals, get the KungLong WP 22 ah, perfect terminals.
It's known as good for the K with or without ABS
http://www.klb.com.tw/dbf/WP18-12.pdf.
We use it here for many years and we are happy.

Very good price and last a long time, starts good in winter.
But sure there are more then 100 others batteries out there, Yuasa or what ever.

Cheers

Chocolate wrote:

Very good price and last a long time, starts good in winter.
But sure there are more then 100 others batteries out there, Yuasa or what ever.

Cheers

If you can get along with 18 ampere hour the Gruber folks make an excellent battery that the R65 folks have used for some time with NO issues. A tick over $40 delivered to your door Stateside. Mine would set all winter with snow outside and fire up with no battery tender.

http://www.gruberpower.com/12-volt-18-amp-hour-ah-battery

There next size up is a 26 ampere hour but the price goes up to $75 which is out of my "cheap charlie" range LOL

http://www.gruberpower.com/12-volt-26-amp-hour-ah-battery-elite

Not a lot of use to the OP as he in in the UK. Postage from the US would probably be 3 times the price of the battery and then the UK customs would probably want duty too.

Sorry for the silly question, but while we're on the subject - how do you get a smaller battery to fit and stay secure? Is it easy? Do you have to pack it out?

My TRX uses a YTX12-BS (10.5Ah) which throws it round a treat, I can't imagine our Ks could possibly need more. In fact I even have a gel (yes, real actual gel) Dynavolt YB9-B (9.5Ah) in the CBX250 that seems to be a bit of a monster, I'd suggest one of those would work a treat too. Can we fit anything we like?

"Looking at those skinny battery terminals and the fact that it is described as a UPS battery and gives no indication of CCA, I wonder how that compares with a Yuasa? UPS systems have very different requirements to starter batteries. 
You might save the price of a tank of fuel, but is it worth it?"

Well, mine lasted 6 years and cost me AU80 dollars, so I'm more than happy. I only replaced it recently as I thought it had failed, but the fault was traced to a dicky starter relay.

Snod Blatter wrote:Can we fit anything we like?

Simple answer is yes as long as it has enough CCA (Cold Cranking Amps) to reliably start the bike, and enough Ah (Amp hours) to give you a bit of a reserve if it doesn't start instantly. How much that is depends on your desire for a physically small battery versus the security of more starting attempts if things aren't going well.

That and avoiding stupidity such as mounting a traditional lead acid battery any other way than upright, and/or not making sure the battery of whatever type is securely mounted so it doesn't bounce around.

Bill

Some very helpful advice here, so thanks to all that have contributed! 

Chocolate wrote:

Holister wrote:…
Many here will agree that you are wasting your money on a litium battery for a K100. …

Hello!

But for a caferacer it could make sense, a caferacer isn't a bike to (only to the next cafe place to showing up :-) to ride long distance.

But if you like, why not have a look in the air industry.
Super B 7800 Aircraft Battery

Cheers

Have you seen the price??  £399!
I can get these for a K1100 for £70.



These work well, I've had one for years.

BobT wrote:My K100RS 16v with ABS is happily starting with a 14 Ah Yuasa gel battery (YTX14BS), 

I too have a K100RS with ABS and am looking around for a new battery. Where is the control unit on your bike? When I purchased my K100 from a dealer there was no tool tray and both the battery and the engne control unit were in the battery tray and the ABS control unit in it's place in the 2 slots at the rear of the battery tray.  I was advised to get a tool tray and put the engine control unit in the slot on that. This would then leave room for a Motoblat AGM 30amp hour battery as I have added heated grips and a satnav. My problem is that the ABS control unit is about 3cms too high to fit under the tool tray. Am I missing something here?

Many thanks

I have a 1985 and a 1987 K100 RS without ABS. This may not be of any use to you but I have enclosed two pictures. One shows the top of the storage tray that sits under the seat. The cover is removed. The other picture is a side view showing a shelf/enclosure under the storage tray where the ignition control unit is installed on these bikes. Storage tray and shelf for the ignition control unit is all one piece.
Shep

Thank you Shep but the ABS control unit fitting slots means that it sits upright directly below the deep part of the tray on the right - and it just does not fit. I have tried the alternative cover recommended for low seats but even that is 3cm too low to accomodate the ABS unit. I could force the ABS unit to lean backwards and make two extended brackets to secure it in place. If I did that though, I cannot see the point of using the low cover instead of just putting the battery, engine control unit and ABS control unit in the battery tray other than it would not accommodate a larger 30 amp hr battery. On the plus side, not having any under seat tray does make working on the bike much easier.

Zara wrote:

BobT wrote:My K100RS 16v with ABS is happily starting with a 14 Ah Yuasa gel battery (YTX14BS), 

This would then leave room for a Motoblat AGM 30amp hour battery as I have added heated grips and a satnav. 

Many thanks

Not sure why you need a huge battery for heated grips and a satnav. The satnav uses so little power that the one on my phone runs for a day without charging. 
A battery exists to start the bike, as soon as the engine is running the alternator supplies the electricity for the heated grips and to charge the battery.

I have a 92 K100LT, its ex police. The ABS unit sits in the under seat tray under the removable cover, not in the rear compartment. As far as I can see there is no modification to the loom, straight fit.

Its ABS1.

Thank you Olaf, an interesting option that I had not considered but having now purchased and fitted an Odyssey PC680 battery, I shall just not bother with a tray - unless someone can give me a good reason to have one.

Thank you BobT. Simple reason actually - because the supplier (not Motorrad) recommended the bigger battery as a replacement for the original part.

PC680 is used in the K1100LT ABS 2.

I always thought part of the reason for such a large battery in these bikes was to run the cooling fan at idle while stuck in traffic? I know my K100rs 4v does not produce much power at idle. Perhaps it is time I had a look at the alternator? It charges well but not until you hit 2000-2500 rpm at least.
I guess you are likely to be a low RPM when you have the ABS in use as well but I don't see that demand being there for any length of time.

The PC680 is a great battery but it is expensive. If you consider the amount of effort required to replace it seems most modern BMW were designed to for infrequent battery changes. The K's aren't too bad.

The ABS will do nothing while you are sitting in traffic, besides, it will not draw much continuous electrical power. 
Bigger batteries being more powerful is such a 1970s thing. Your PC680 has way more cranking amps (CCA) than the older lead acid battery that is twice the size and twice the weight.
The idea of an alternator rather than an older dynamo is that it very quickly produces electrical power at low revs. Fitting a voltmeter will assure you that it is working fine.

BobT wrote:The ABS will do nothing while you are sitting in traffic, besides, it will not draw much continuous electrical power.

You are absolutely right but I was thinking of what the draw might be when you slam the throttle shut and grab all the brakes you can find. At the same time the cooling fan, heated grips, lights, vest, running lights, GPS, stereo, cell phone, x-box, beer cooler and sat phone are running. Does anyone know off hand what the ABS servos (for lack of a better name at the moment) draw for amperage?

Of course you would immediately return to modulating the brakes and using engine braking for the rear to perform the shortest possible emergency stop from 120kph+ to 0kph.

I am sure even the smallest oldest battery that would regularly start your K would have a enough juice to save that front end tuck in an emergency stop.

gorio wrote:I know my K100rs 4v does not produce much power at idle.  It charges well but not until you hit 2000-2500 rpm at least.

How did you arrive at those conclusions, gorio?

Just using the aftermarket voltmeter on the bike. I guess an amp meter might be a better tool but I don't have one.
I did read somewhere and I think it was this forum that this was fairly typical of the charging systems on the K's.

What's your moto's idle revs and what's your voltmeters reading at idle?

Laitch wrote:What's your moto's idle revs and what's your voltmeters reading at idle?

idles about 900-1000rpm as a rule
depending what I have turned of course. lights and nothing else about 12.8V at idle. so basically maintaining battery voltage. At 3000rpm you would see 13.8-14V

gorio wrote:idles about 900-1000rpm as a rule
depending what I have turned of course. lights and nothing else about 12.8V at idle. so basically maintaining battery voltage. At 3000rpm you would see 13.8-14V

It's right where it should be. If you're concerned about discharging the battery by hitting the brakes and activating the ABS because it's already being taxed by the grips, driving lights, food processor and autoclave, don't brake—swerve.

Laitch wrote:swerve.

I hate to swerve with the stuff in the microwave, something always spills.

Where do I buy the microwave?
Shep

gorio wrote:

Laitch wrote:What's your moto's idle revs and what's your voltmeters reading at idle?

idles about 900-1000rpm as a rule
depending what I have turned of course. lights and nothing else about 12.8V at idle. so basically maintaining battery voltage. At 3000rpm you would see 13.8-14V

That is fine then. Your battery should start the bike down to about 12.2 volts so 12.8 is charging the battery and supplying enough energy to run what is switched on. The regulator will keep this at above battery voltage as much as it can. 
How much time do you spend at idle with everything switched on?

I have two bikes in the garage with alternators that turn off the battery idiot light, but unless the engine is idling above 1500/1600 rpm the voltage output is only about 12.7v.. That is enough to turn off the light, but the alternator output certainly isn't putting out enough to run the electrical system.

It's not a big deal, the bike will run for quite a while on the battery. If you get stuck in traffic, just make sure to get 15-20 minutes of running after you get rolling again and you'll be fine.

My K75's the same as Point-Seven-Five's bikes.  Low voltage below 1600 RPM but adequate above that value.

Jumping in here, as I don't think my query deserves its own post ;-)

Does the alternator need some alterations to work with these more modern battery chemistry?
My '85 K100 RS has a dud battery after no use over the winter, and want to replace it. The one in there when I got her was a Yusa 52515 (12v 23.3Ah), but from what I understand, the norm was the Yuasa 53030 (12v 28Ah). I'd like to switch to a AGM or gel for less hassle, and wanted to confirm if any voltage limiter or such is required when swapping in a AGM/gel battery?
My options are the OEM Exide battery from BMW (12V 19AH) or the Motobatt AGM MB51814 (22Ah) -- I'm leaning towards the Motobatt for the extra reserve crank attempts, but either should be fine right? :-)

I have had several Motobatt and all have given good service. The 30Ah one in my K100 went for 7 years then got transferred to the K1100 and I got a further year from it.  If you decide on a Motobatt have a look around the Jetski and lawn tractor sections they are often cheaper there for the same one.

Motobatt, no problem. The one in LFB has been there ten years now and has never given a problem. I also have one in Kostenlot (yeah guys - I'll finish it one day ) and a spare  on the bench. Long story....

Got this in mine working out ok

Thanks for the inputs, have ordered the Motobatt AGM MB51814 (22Ah).

Jibe wrote:


Got this in mine working out ok

Wow, I'd be thrown out of the house if I were to place any greasy bike parts on the coffee table ;-)

Clean motorcycle parts are usually okay.
Shep

As good a thread as any to continue.

On my K75 RT, the battery hold down bracket also holds the coolant overflow container in place, and it fits exactly with the 175mm tall (once) 24AH battery.

If I were to fit a lower battery, the coolant overflow container would be squashed, unless I place a spacer under the battery. Is that the way to do it?