Battery question (new owner)

[Anglo saxon17 28]

Hello all ,

this is my first post and have owned a 64 plate 750s a week now (previous owner was my dad ) 

just have a question about the battery before I buy a new one , basically I bought the bike back home last Saturday and fitted a tail tidy with LED back lights and indicators the next day the battery was flat and she wouldn’t start so after 24 hours on my optimate the battery was charged again and have done about 20 miles on it since (the latest being this morning for a local ride about) 

I put the optimate back on when I got back to check as the start up sounded a bit week and it’s back on orange (not fully charged) so charged it again to green but want to know if anyone else has experienced this as my dad says it has always started no problems and he has been touring to Europe on the same bike ,could it be the LED lights or is it in not running it enough to top the charge up or could it be the battery just needs replacing , I’m thinking of swapping the 10 AH to possibly a 12 AH has anyone done this or bigger ? Before I start spending money on batteries (already spent 250 quid and only had it a week on the tail tidy and a new slip on but that’s what we do can’t help it 😂

[Tegraman 4,060]

Disconnect one battery connector, so that the battery is definitely out of circuit, then connect your test meter leads to each of the ring terminals on the battery wires (to repeat, not the battery). With the ignition switched off, the resistance shown on your test meter should be infinite. (usually shown by a “1” on the test meter display.) If it is anything other than infinite, the current flowing can be calculated by dividing 12 (or whatever is the battery voltage if you are being precise) by the ohms reading on your meter.

There should be no current flowing, but you will then know how much juice is “leaking” when the ignition is off. It might pay to start looking at any “new” changes to the wiring. It is a good idea to always put any additional new electrical loads onto the switched circuits, i.e. not directly onto the battery or any live circuit prior to the ignition switch.

You could just interrupt one battery lead via your test meter with the meter switched to “amps”, but meters are rarely accurate in that mode, so it would be less helpful for your diagnosis. 

Generally, replacing the battery with one with greater capacity will just (a) cost you extra, and (b) be hard to cram into the battery space.  It won't cure a constant discharge problem, just take a bit longer to become fully discharged. Your original battery should be charged up, then disconnected from the bike wiring. After a few hours for it to “settle”, measure the voltage across the battery terminals, then repeat a week later with the battery at the same temperature as it was on the first test. There should be no difference. A full-current test is not advisable, it can be dangerous if done DIY, so don’t do it. The safe way to test the battery is to judge whether the starter is “enthusiastic” on the start button.

 

 

 

 

 

 

Edited April 12 by Tegraman

[Slowboy 25,328]

Please don’t take this as a harsh comment, but unless you’ve been really unlucky and the battery has started failing just as you’ve done these mods, I’m afraid it looks most likely that something you’ve done as part of the modifications has started this off. Tegramans post above is a really good place to start, but have a real close look at the mods you’ve done to be absolutely sure it’s been done correctly. 
We’ve all done something like it at some time, but you’ll need a meter and a wiring diagram to trace your way through it.

if you’ve only fitted rear lights and indicators, are your front indicators still the bulb (filament) type? 

 

If so I’m suprised the rear indicators are working properly as LEDs have a different impedance to filament types and need a different relay or resistors in the line to get the right flash rate.
 

The kit you fitted should have had all the relevant information with it. This only applies to the indicators, not the rear lights.

 

If you could take and add some photos, that might help.

Edited April 12 by Slowboy

[Viator 2,427]

Welcome @Anglo saxon17 Some great advice by @Tegramanand @Slowboy 👍How old is the current battery and is it a decent quality one? If +3 years old or cheap almost certainly worth replacing anyway.

In my experience of using Optimate chargers they will always show orange on startup no matter the state of the battery so don't read anything into that. They usually charge for around 30 mins then monitor the discharge and then charge/condition as required.

[Rocker66 38,178]

1 hour ago, Viator said:

 

In my experience of using Optimate chargers they will always show orange on startup no matter the state of the battery so don't read anything into that. They usually charge for around 30 mins then monitor the discharge and then charge/condition as required.

That’s always been our experience of the optimates.

[Andy m 27,490]

Welcome to the forum.

 

"Smart" chargers generally work to a cycle. Some sort of light to warn about bad connections often red, a typical yellow to show it's running then the green after a timer has run down and the voltage is steady above 13V. Yellow light the morning after isn't good, but after an hour doesn't tell you much.

 

Very good advice above, I also think the changes are a leak to ground. LED indicators with a non-electronic relay are a poor design.

 

Andy

[Anglo saxon17 28]

Thanks for the reply’s I will have to buy a meter as mines gone missing since moving house so will have to do it next week ,and yes the front are normal bulbs but I have put some resistors on the rear so the flash at the normal rate ,the tail tidy is an R&G one which came with the LED lights the indicators are not so will look into it thanks ,will post pictures in a bit 

[Anglo saxon17 28]

And just spoke to my dad the battery is definitely on older than 3 years could be as old as 5 so wouldn’t surprise me if some cells are gone will be getting a new one Friday either way for peace of mind 

[Anglo saxon17 28]

Just been out for a quick ride about started no problem bought it back plugged in the  optimate and  it is orange so think it’s me getting paranoid about the orange light which I’m waiting to see how long goes to green but will be buying a new battery anyway now I know the age 

[Anglo saxon17 28]

It’s definitely me being paranoid optimate went to good/green so I took it off started it and plugged it back in now it’s orange again but noticed the HISS light flashing red on the dash so called my dad and it went off about 12 months ago he said so the battery must be ok or better as it’s still on without the optimate plugged in ,but will be buying a new battery Friday just for peace of mind thanks for the responses and help on my first (and no doubt many more to be ) post on this forum 👍🏻

[Viator 2,427]

Sounds very much like the battery had just got rather low. If the bike will be in regular use there should be no problem but if you are not going to ride it for a few days or weeks connect the Optimate and leave it on as it is designed to gently cycle and maintain the battery. I leave an optimate connected to my Harley for months over the winter, never take it off, it's what the Optimate is designed to do. 

Enjoy your new ride and keep posting 😎👍

[poldark 2,212]

Be careful with replacement battery as there's quite an awkward cable angle and terminal fitting, on the left (think it's positive)

 

First replacement battery I bought would not fit comfortably, not physical size, just the terminal connector.

 

I ended up getting a very good deal from SBS on one of these

 

 https://www.that auction site.co.uk/itm/224590367093

 

[Slowboy 25,328]

Thanks for filling in all the details @Anglo saxon17, that might be very useful for someone else.

[Anglo saxon17 28]

Just a quick update I ended up contacting my local bike shop who I have been to for years gave him the current (yuasa) battery model number to price a replacement up and it came back as the wrong one with a lower crank wattage as well as being old so got the correct me (yuasa) again for £89 as he knocked a ten we off for me but the same ones I found online start at £155 and since then no problems it consistently sits at 12.75 when ignition is off and starts with a tickle of the starter button now so thanks again for everyone’s input 

[EdG 421]

Result.

[Tegraman 4,060]

Yet again, your instinct trumps all the guff from the forum elders . Kudos to you.