daveinlim Posted March 1, 2020 Share Posted March 1, 2020 I must have left the parking lights on last night. My bike wont start today. The light, display wont come on and all was well with the bike up until then. Can I get a jump from a car battery or does it have to be another bike?Or do I need a new battery?Bike is a 2018 gsxs125 Thanks Quote Link to comment Share on other sites More sharing options...
Stu Posted March 1, 2020 Share Posted March 1, 2020 You can jump from a car but do not start the car as the high amps from the cars charging system will kill the bikes battery!As for needing a new battery only time will tell! Usually they are fine if not left for long periods Quote Link to comment Share on other sites More sharing options...
Mississippi Bullfrog Posted March 1, 2020 Share Posted March 1, 2020 Bear in mind that if you jump start it and ride it for quite a long way it will only partially recharge the battery. Modern charging systems do not fully recharge flat batteries. So it's worth investing in a decent charger suitable for bike batteries, ie one capable of charging at low amps. A car battery charger is too powerful to use on bike batteries regularly. Quote Link to comment Share on other sites More sharing options...
Fleck Posted March 1, 2020 Share Posted March 1, 2020 The Lidl chargers are ok. Got bike and car modes, an LCD Display and only £13.99 Quote Link to comment Share on other sites More sharing options...
gogs01 Posted March 1, 2020 Share Posted March 1, 2020 Bear in mind that if you jump start it and ride it for quite a long way it will only partially recharge the battery. Modern charging systems do not fully recharge flat batteries. ...... I understand the advice on battery tenders / chargers, but why won't the bike's own charging system fully charge the battery ? My understanding is that most bike's charging systems have a fairly large spare capacity. Quote Link to comment Share on other sites More sharing options...
Mississippi Bullfrog Posted March 1, 2020 Share Posted March 1, 2020 Bear in mind that if you jump start it and ride it for quite a long way it will only partially recharge the battery. Modern charging systems do not fully recharge flat batteries. ...... I understand the advice on battery tenders / chargers, but why won't the bike's own charging system fully charge the battery ? My understanding is that most bike's charging systems have a fairly large spare capacity. It's to do with how they are regulated. Ye olde dynamo charging systems would fully charge a flat battery but modern systems don't. They whack in a healthy charge more quickly but then tail off before the battery is at max charge. In the days when you could get into batteries I used to measure the specific gravity of the electrolyte to determine the state of charge and most healthy batteries were rarely above 70% of full capacity. They still worked ok.But if a battery is totally flattened it's good practice to bring it back to max charge using a charger. The bike's system will then maintain it at a higher level of charge than just running the engine to put some charge into it.Looked after properly they last longer. My car battery is 20 years old which isn't too shabby. Quote Link to comment Share on other sites More sharing options...
Phill Posted March 1, 2020 Share Posted March 1, 2020 I must have left the parking lights on last night. My bike wont start today. The light, display wont come on and all was well with the bike up until then. Can I get a jump from a car battery or does it have to be another bike?Or do I need a new battery?Bike is a 2018 gsxs125 Thanks I had to jump start my friend's bike using my car, with ignition off. In our case it was fine! Quote Link to comment Share on other sites More sharing options...
daveinlim Posted March 1, 2020 Author Share Posted March 1, 2020 So I got the bike started thanks to a call out from AA. Nice guy, gave it a jump and checked it was all running ok. I took it for a spin for an hour after to charge it up. Stopped for fuel and it started again no problem. I'll know if it is all ok when I go to start it in the morning. Quote Link to comment Share on other sites More sharing options...
Mississippi Bullfrog Posted March 2, 2020 Share Posted March 2, 2020 Several manufacturers of chargers for bikes do remote connection leads with LEDs that tell you exactly how much the battery is charged. I have the CTEK ones on both bikes and fitted to my spare battery. If the bike is just run to charge the battery it will flash green for about a week before dropping to the yellow light. It still starts fine when on yellow. You don't need the battery to be 100% charged to start the engine.If I use a charger the battery will stay green for a month before dropping to yellow.Glad it's sorted but still worth getting yourself a charger to maintain your battery for longer life. Quote Link to comment Share on other sites More sharing options...
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