Mouse
Registered user
The OEM battery in my 1200 seems to be on the way out. I've been having problems with the accessory socket (which are not proven to be due to a weak battery but I strongly suspect they are), and last week my Optimate pronounced the battery to be "weak".
First thing in the morning, after a decent overnight charge, the bike was fine, but as the day went on and I started the engine more times I could hear the starter motor struggling more and more. Eventually it got to the point (at the PJM rally, off road riding means more starts per mile than tarmac, for me at least!) that when I started the engine, the voltage drop caused the ABS to reset and turn back on. I had to bump start a few times to stop this happening.
So I decided to fit a better battery. I could have got a replacement under warranty but odds are that that would suffer the same problem in 18 months. A bit of investigation suggested that the Hawker PC535 is suitable for the GS, but it wasn't that simple.
One supplier listed a "PC535GS" on their website as "the battery for the R1200GS". However when I tried to get one of these from a more local place (Cheshire Batteries - 01270 255493) they said it didn't exist. It transpired that the other supplier had modified the standard PC535 in some way to make it suitable for the 1200. However Cheshire Batteries were only asking £60 for a PC535, over 30 quid cheaper than the other place. So I went to their shop, and they were extremely helpful, allowing me to try out the new item in the bike before I handed over the cash.
I decided I could probably make the battery fit in the 1200, it turned out to be a bit more work than I expected
The main problem is that the Hawker is bigger than the standard (A Yuasa YTX-14-BS). The OEM battery measures 150 x 85 x 145 mm, while the Hawker is larger at 170 x 99 x 155 mm. However it does, just, fit into the battery compartment of the 1200.
There were several problems I noticed:
1 - Theres a hard brake line that passes along the right hand side of the battery compartment. The larger battery was putting pressure on this, and while it probably wouldn't damage it, it didn't seem like good practice.
2 - The new battery is taller, bringing the terminals uncomfortably close to the metal mounting bar at the front of the seat. Again, it would have probably been ok, but if the battery was to get dislodged it could potentially short circuit through this bar.
3 - The metal strap that secures the battery into the compartment would not fit round the larger battery.
4 - The connectors on the bike's wiring loom would not fit comfortably onto the terminals of the Hawker, which ironically are much smaller than on the OEM item.
So, bodge-man swung into action
Firstly, I decided to mount the battery with the terminals towards the rear of the bike. This means there's no chance of a short on the seat bar. but does mean that the electrical wires going to the battery are now in the wrong place.
The Hawker battery actually has plastic "fins" on the sides of the case, which make it wider than it needs to be. I cut out some slots in these fins to stop it fouling the brake line on the right.
Secondly I modified the battery securing strap. This was the point at which, if this whole thing didn't work, I'd have to be buying new parts from Mr BMW
I heated the strap in a blowtorch and removed most of the bends from it, leaving it with a single right angle bend to coincide with the top of the battery. I didn't totally remove the "springy" bend in the long section, so it still retained a bit of spring. The modified strap was just long enough to go round the larger battery, although I had to use a small spacer on the screw that holds it in.
The Hawker comes with right angled thingies on the terminals. The negative one had to be bent upwards slightly, so that the bolt holding the lead onto the terminal didn't foul the frame, as seen in this next picture. I also had to reroute the cables from the bike to get the negative lead to reach this far.
This was the real point of no return. The connector on the positive lead is so large, that if mounted directly onto the terminal of the battery it would have been dangerously close to the frame. And the positive lead is so long (remember it is meant to reach over to the right side of the battery) that there was a lot of excess wire.
So I cut about an inch of cable off the end of the lead. The lead is actually four seperate wires, of varying thickness. I soldered smaller ring connectors onto these wires, one on the thickest wire and another one onto the three remaining wires. This made the cable just the right length to be routed under part of the frame to the terminal. I removed the right angled thingy from the battery positive terminal and attached both ring connectors directly. (The green wires in the photo are powering my aux lights). Finally I trimmed the rubber cover down to size and everything was good to go
Initial impressions are good - the bike starts just as well as it did with a well charged OEM battery. The accessory socket and ABS haven't played up yet, although I've only done a short test ride so far. The real test will be next time I go trail riding and stall the thing 15 times in a day
First thing in the morning, after a decent overnight charge, the bike was fine, but as the day went on and I started the engine more times I could hear the starter motor struggling more and more. Eventually it got to the point (at the PJM rally, off road riding means more starts per mile than tarmac, for me at least!) that when I started the engine, the voltage drop caused the ABS to reset and turn back on. I had to bump start a few times to stop this happening.
So I decided to fit a better battery. I could have got a replacement under warranty but odds are that that would suffer the same problem in 18 months. A bit of investigation suggested that the Hawker PC535 is suitable for the GS, but it wasn't that simple.
One supplier listed a "PC535GS" on their website as "the battery for the R1200GS". However when I tried to get one of these from a more local place (Cheshire Batteries - 01270 255493) they said it didn't exist. It transpired that the other supplier had modified the standard PC535 in some way to make it suitable for the 1200. However Cheshire Batteries were only asking £60 for a PC535, over 30 quid cheaper than the other place. So I went to their shop, and they were extremely helpful, allowing me to try out the new item in the bike before I handed over the cash.
I decided I could probably make the battery fit in the 1200, it turned out to be a bit more work than I expected
The main problem is that the Hawker is bigger than the standard (A Yuasa YTX-14-BS). The OEM battery measures 150 x 85 x 145 mm, while the Hawker is larger at 170 x 99 x 155 mm. However it does, just, fit into the battery compartment of the 1200.
There were several problems I noticed:
1 - Theres a hard brake line that passes along the right hand side of the battery compartment. The larger battery was putting pressure on this, and while it probably wouldn't damage it, it didn't seem like good practice.
2 - The new battery is taller, bringing the terminals uncomfortably close to the metal mounting bar at the front of the seat. Again, it would have probably been ok, but if the battery was to get dislodged it could potentially short circuit through this bar.
3 - The metal strap that secures the battery into the compartment would not fit round the larger battery.
4 - The connectors on the bike's wiring loom would not fit comfortably onto the terminals of the Hawker, which ironically are much smaller than on the OEM item.
So, bodge-man swung into action
Firstly, I decided to mount the battery with the terminals towards the rear of the bike. This means there's no chance of a short on the seat bar. but does mean that the electrical wires going to the battery are now in the wrong place.
The Hawker battery actually has plastic "fins" on the sides of the case, which make it wider than it needs to be. I cut out some slots in these fins to stop it fouling the brake line on the right.
Secondly I modified the battery securing strap. This was the point at which, if this whole thing didn't work, I'd have to be buying new parts from Mr BMW
I heated the strap in a blowtorch and removed most of the bends from it, leaving it with a single right angle bend to coincide with the top of the battery. I didn't totally remove the "springy" bend in the long section, so it still retained a bit of spring. The modified strap was just long enough to go round the larger battery, although I had to use a small spacer on the screw that holds it in.
The Hawker comes with right angled thingies on the terminals. The negative one had to be bent upwards slightly, so that the bolt holding the lead onto the terminal didn't foul the frame, as seen in this next picture. I also had to reroute the cables from the bike to get the negative lead to reach this far.
This was the real point of no return. The connector on the positive lead is so large, that if mounted directly onto the terminal of the battery it would have been dangerously close to the frame. And the positive lead is so long (remember it is meant to reach over to the right side of the battery) that there was a lot of excess wire.
So I cut about an inch of cable off the end of the lead. The lead is actually four seperate wires, of varying thickness. I soldered smaller ring connectors onto these wires, one on the thickest wire and another one onto the three remaining wires. This made the cable just the right length to be routed under part of the frame to the terminal. I removed the right angled thingy from the battery positive terminal and attached both ring connectors directly. (The green wires in the photo are powering my aux lights). Finally I trimmed the rubber cover down to size and everything was good to go
Initial impressions are good - the bike starts just as well as it did with a well charged OEM battery. The accessory socket and ABS haven't played up yet, although I've only done a short test ride so far. The real test will be next time I go trail riding and stall the thing 15 times in a day
