IME you will only get 12.9v from a good fully charged bike battery when the ambient/battery temperature is over approx. 15c. At this time of year if the bike and or battery are in an unheated garage at -6 to 10c the same condition/charge state battery will sit at 12.7/12.8v.
This is a handy yoke - http://www.actmeters.co.uk/battery-testing/612-6v-12v-battery-tester It simulates a 20 hour discharge test .... reasonably priced and British made
Got the voltmeter to work. only 5 v with no load on the battery after days of charging. Although the charger has a car/motorcycle switch. I reckon that the motorcycle option (which I was using) is a bit weak. I've put the charger on 'car' to see if it makes any difference.
I got two scrap batteries now. I'm gonna see if my solicitor knows if I could claim for them. They are duff now but only because they were left for over 9 months uncharged. Of course, one could argue that they may of needed replacemnt at some pont anyway.
I have successfully recovered 2 car batteries and a bike battery with the Noco Genius, which has a repair mode to bring life back into old batteries. It also acts a battery conditioner, and can be left connected continuously when it gets to fully charged. Might be worth investing in.
Sir, yes we understand your garage & part of your house burnt down. But, we've found a internet post in which you displayed without offence, gay abandon. And were using a higher alternative mode on your electrical device.... @PerryL "...yes but but.."
I have recovered a completely flat battery that had been standing using a very cheap trickle charger, my optimate wouldn't look at it, i'm still using the same battery years later.
Please can you do a drop test and confirm it still has more than 30% or more of the new ones capacity?
It went completely flat, my optimate wouldn't charge it, a cheap £8 trickle charger recovered it, my optimate now keeps it going nicely and it is still starting my ducati many years later. As you know Ducati don't like poor batteries. Can't say more than that. That's my experience, I'm happy. Steve
There is a REALLY good reason an intelligent charger won't try to charge a low battery.... I wonder what it is? Note Battery charger manufacturers do not sell batteries.... Have a think about it. What a wonderful feature to be able to slowly bring a battery from 0.00V to 13.8V would be for any manufacturer who wanted to be ahead of the competition. Invest in a DROP tester circa £15 and it will tell you EVERYTHING you need to know about the batteries ability to start a bike or car. I've got 12 motor vehicles here and at least 4 spare batteries (all on tenders), believe me if there was a way of avoiding buying new batteries I'd have sorted it long ago.
I've ordered the charger mentioned above AND two smoke detectors have arrived. I really should of put smoke detectors in years ago. Not only have I a motorcycle downstairs but I have a washing machine and tumble dryer. They run during the night because I get cheap rate leccy off-peak. I've got smoke alarms upstairs but I live in a coach house with my garage and workshop below.
If you are going to proceed with this experiment, keep an eye on the temperature of the "bad" battery, checking each of the 8 cells in turn, one or more may be silly hot (boiling the sulphuric acid, then melting the plates). Make sure it's on something that cannot catch alight or react to any acid that may be lost. Keep away from pets and children including any adults who aren't aware of the experiment.
