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I Need A New Battery.

2K views 16 replies 8 participants last post by  The Mariner 
#1 ·
My '15 F800R is nearly four years old. I haven't been riding it enough and lately the battery has been very sluggish. Cooler weather is probably the culprit. Time for a battery change I think.

Since my F800R is loaded with electronics, is there anything I should watch out for?

Thanks in advance.
 
#2 ·
My '15 F800R is nearly four years old. I haven't been riding it enough and lately the battery has been very sluggish. Cooler weather is probably the culprit. Time for a battery change I think.

Since my F800R is loaded with electronics, is there anything I should watch out for?

Thanks in advance.
Remove the negative cable first to avoid short circuiting the positive terminal. When installing, do the positive first.

Clean the wire connectors (sand paper is great.) Some anti-corrosion spray is helpful.

As for battery choice, I don't think there's much need to deviate from stock - I certainly haven't read much on increasing battery size.
 
#3 ·
Thanks Andrew.

Removing the negative connection first and cleaning all terminals is a given.

No fiddly electronics that may give me trouble? Why I'm asking is, I've never changed the battery in a 'modern' bike before.
 
#4 ·
If you are careful and do not short circuit, everything should be fine.
The only point is that the service date will be reset, so you will need to live with a constant service warning or have the date corrected by a dealer or with a GS-911 or similar.
 
#6 ·
Thanks Frank..

I didn't get the service reminder reset last time I had an oil change, so it's been on since then. I had my bike in for an interim oil change at my local bike shop which isn't a BMW dealer. No biggy.
 
#5 ·
Also, I wouldn't spend a lot of money on a battery either. I look for the CCA rating of the OEM battery and then do a search for batteries that size and amperage. I paid $55 I think for my last one.

Chris
 
#7 ·
Jurgen,

Mine is a 2015 F800R as well, and I don't do many miles. Last winter (southern hemisphere) I had a similar issue and have been putting it on a trickle charger before a ride for about 3 - 5 hours sometimes if I remember overnight, and its been fine and once its spring and summer no issues at all. I also have a GPS and denali lights etc etc, but all through the canbus so nothing is left on. You may already know all this... just my 2centsworth.

Re batteries I would look at OEM type AGM minimum 12 AH battery.
 
#9 ·
Jurgen,

Mine is a 2015 F800R as well, and I don't do many miles. Last winter (southern hemisphere) I had a similar issue and have been putting it on a trickle charger before a ride for about 3 - 5 hours sometimes if I remember overnight, and its been fine and once its spring and summer no issues at all. I also have a GPS and denali lights etc etc, but all through the canbus so nothing is left on. You may already know all this... just my 2centsworth.

Re batteries I would look at OEM type AGM minimum 12 AH battery.
We've had a few cold nights here on the south coast, Pete. Probably similar to what you're getting in Sydney. I've been pretty busy with family things and haven't taken the BMW out much lately, although I ride the little Super Cub most days. Maybe I do need to buy a trickle charger. I guess I could always jump start it via the Super Cub if I'm really stuck. I think a new battery would be the best option at the moment.
 
#8 ·
I changed my battery last month. I noticed that the wires easily moved back toward the battery terminal after I released the nut.
This momentary reconnection didn't seem like a good thing so I covered the loose wires with a cloth and made a good effort to tuck them away from the battery area.
 
#10 ·
You might want to see if you can resurrect the battery with a charger first. Another alternative that I carry with me all the time, is one of those jump packs, aka battery booster. They're small and easy to carry with you. And they'll jump start a completely dead car, so they'll work just fine for your motorcycle.

Chris
 
#11 ·
You might want to see if you can resurrect the battery with a charger first. Another alternative that I carry with me all the time, is one of those jump packs, aka battery booster. They're small and easy to carry with you. And they'll jump start a completely dead car, so they'll work just fine for your motorcycle.

Chris
I might give this a go, Chris.
 
#12 ·
I've taken on Chris' advice and put the battery on charge this morning. It took several attempts to start my bike this morning as the battery was more sluggish than previously. I'll leave it on charge for half a day or so. Charging might just rejuvenate the battery. Here's hoping.

This morning is the first time I've actually removed the cover off the faux tank. I had a good snoop around. Changing the battery should be a snack.
 
#14 ·
Most bike batteries these days are available with 2x positive terminals & 2x negative terminals. I use a pair of 1.2m long leads with alligator clips on them & 2x of M6x25 bolts. Screw the bolts into the spare terminals (not the ones you'll be connecting the bikes leads to) on the new battery & put it on the ground next to the bike. Clip one end of each lead wire to a bolt and tape it in place with insulation tape. Ensuring you connect +ve to +ve & -ve to -ve, connect the other lead wire to the +ve & -ve battery lead on the bike.

This puts the new battery into parallel with the old & it will keep the bike powered while the old battery is disconnected & removed. No change to service indicator, clock etc.

Once the old battery is removed, while keeping the leads connected carefully fit the new battery & connect the bikes battery leads to the empty terminals. Once it's connected you can carefully remove the jumper leads & the M6x25 bolts.

It's a bit tricky to make sure nothing shorts-out but take your time & it'll be fine.
 
#15 ·
Bump [:)] Apologies Resurrecting an old post.

My battery has started to be sluggish when starting the last few weeks. Tightened terminals just to be sure. I had the bike on a trickle / float charger a day before the ride.
Rode approx 140 km, but every time I stopped the start was sluggish, but it did start. came home the voltage showed (checked on pigtail with multimeter) 12.7v
After 2 days it shows 2.5, but when I tried to start it was sluggish. So started sluggish, run for 1 minute then shut down, start again - very sluggish, try again in a minute very sluggish, then shut down and try third time immediately would not start , so left for 1 minute - very very sluggish but starts. shut down and check voltage 12.2 but then checked again after 10 minutes - voltage back up to 12.5v.

PS - have not ridden it regularly for about 4 months due to lockdown, but I did put it on a trickle every few weeks as it was winter here.

Almost 6.5 years (bought new July 2015) time for a new battery I reckon

Any suggestions for a good AGM battery in Australia for a 2015 F800R ?
 
#16 ·
Two missing data points that would have been interesting: voltage with motorcycle running, and possibly if you can catch the voltage while starting. Even without those I agree it is time for a new battery. No-load voltages you cite are reasonable but no-load voltage tells us nothing about how much current can be sourced under load.

If no-load was under 12.0V then we would have reason to believe you have a shorted cell.

If running voltage does not rise then we suspect the charging system. Is reasonable to be as high as 14.5V even with your weak battery. A weak battery with all cells good is easy to bring to a high voltage. If one cell is shorted then higher currents are needed because the good cells are being overcharged.
 
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