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Lithium battery going (very) flat?


jlparsons
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Hi folks, have changed my BMW F800GT over to a lithium iron phosphate battery after my old lead acid one finally died. The lithium one has been working fine for a few weeks then suddenly one morning I come to start my bike and it's very, very flat. Like not even a flicker from the instruments - never seen that before. Usually when you have a flat battery the instruments come on and you at least get a click from the starter solenoid before failure to start.

I connected up my lithium battery conditioner which said the battery had extremely low voltage so it automatically did a slow start and then charged it. Now it's working fine again, but obviously something has gone wrong somewhere and I don't want to get stranded somewhere...

I've been doing lots of short trips and have had the heated grips on, so I'm thinking that might have done it by pulling more charge out than the engine is pumping back in over a couple of weeks, but seems very unlikely and wouldn't kill it absolutely flat like that surely? I've checked the alternator output which was fine at 14v, and the current drain with the bike off which was 1.9 miliamps. So I'm a bit at a loss. Anyone experienced similar phantom current drain with lithium iron batteries?

I've now taken the battery out of the bike and connected it to the conditioner which will test it over the next 24 hours or so for voltage drop after charging.

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I would get in contact with the seller and tell them its faulty.


A lithium battery should last at least 10 years and never go flat under normal circumstances.. towards the end of its life then it would just have less oomph and engine starts will begin to be a struggle. But it should never go flat like you describe. Especially from nearly new.


assuming its fully charged.. and you start a bike from cold. it should be back up to full capacity within 10 minutes so only repeated rides withe multiple stops and engine restarts should have any kind of negative effect.. and multiple is an understatement.


I would guess that the built in hardware that governs the battery charging management is faulty.. or perhaps the cells themselves. If this has happened once then it is almost certain to happen again.


Contact the seller and tell them its faulty and demand it is either replaced or get a refund.


A later edit.

 

The lithium one has been working fine for a few weeks then suddenly one morning I come to start my bike and it's very, very flat. Like not even a flicker from the instruments - never seen that before. Usually when you have a flat battery the instruments come on and you at least get a click from the starter solenoid before failure to start.

 

This is normal. just like a phone will turn itself off when the battery gets very low. so has your battery.

It isn't completely flat, it has reached a point where it has disabled itself. A lithium battery should never go completely flat as this is harmful.

Edited by Gerontious
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I'd like to hear the resolution to this one.


I thought that, because lithium batteries are fundamentally different from lead acid, they may be better but only in the right environment. They need lithium - specific chargers, so doesn't the bike's charging system need to be suitable too ? Bikes which come with lithium batteries from new may have subtly different charging systems.


Also, do they cope with temperature in the same way as lead acid batteries ? I've read about them needing to supply current to a headlight before they're "warmed up" enough to start a bike.


Maybe I've got it all wrong, but I'd have to do a great deal of research before I switched from lead acid to lithium.


Can't wait to see the final outcome ..... :thumb:

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Maybe I've got it all wrong, but I'd have to do a great deal of research before I switched from lead acid to lithium.

 

Its only a matter of time before you will not have a choice, thats assuming you are buying a new bike over the next few years.


With my Honda... I didn't have a choice it came with a Lithium as standard and so there is no room to put a normal battery on the bike, and thats the way of the future, as the years go by they will take over.. just as the original mobile phones had a car battery to power them (first in a car.. then shortly afterwards in a very heavy carry case), then it went to rechargeable alkaline, then nickel and finally lithium. Nobody thinks twice about the lithium battery in their phone and the idea of moving back to either alkaline (or nickel) or even a car battery is ludicrous.


Lithium batteries are far superior in every way to standard lead acid. one guys faulty one is just that. for all I know he could have bought a fake. or (more likely) one with a fault as I suggested. If you bought a Samsung phone that went flat after a few hours what would you do? you would take it back.. and get another. the chances of two bad ones is pretty low. Likewise if your phone battery died.. you would simply get another.


Batteries you buy to replace a standard acid battery are mostly empty box.. because lithium is considerably smaller. They also have hardware/software built in to cope with the bikes charging system. bear in mind that an AC battery charger works in a slightly different way and can be used in a lithium.. but only up to a point. Battery 'conditioners' are totally unsuitable. so anything like a Oximiser. or an Optimate.. cannot be used.


for total peace of mind you really do need a lithium specific charger.


The battery is unaffected by temperatures down to -10 and higher cranking and capacity that its lead acid equivalent. it recharges its power loss in minutes and should last 10 years or more. when the bike is stored.. it loses 1% of its charge per month. so doesnt need to be touched if the bike is stood over winter and not ridden for 6 months. even a year standing wont affect the first start-up. 12% loss is nothing. (this has already been tried)


Does your phone battery need 'warming up'? its almost the same technology. In fact its only because of the advances in batteries for phones that we have these things for bikes.. the one has lead directly to the other.


There is only one downside to a lithium battery and that is that it cannot be jump started. but then.. there should never be any need to do that.

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I've used lithium's for years in model aircraft, always with specific chargers. As asked above....the bit I'm not sure about us whether you can fit one into a bike made for lead acid batteries. If lithiums need specific chargers does that not also apply to the bike's charging system?


I've heard of a few folks fitting lithiums into older bikes and having problems with the battery not charging.

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If lithiums need specific chargers does that not also apply to the bike's charging system?

 

No.. its built in. a module of sorts that is in the box.. takes power from the bikes charging system and does a bit of tinkering to make it suitable. These are built in to Lithiums that are designed to replace the OE lead acid. Or where the OE battery was a choice of standard or lithium. Which is how Honda started with the very high end bikes like the SP and SP2.


A lithium battery can cope with a very basic trickle charger - not ideal, but enough in an emergency. (this has been tried) The advice is to plug it in for no more than 30 minutes. Put the battery back in the bike start it and go for a ride. An hours riding is enough to bring it to full charge.


anything more complicated than that will kill it. So, you cannot use anything that is even remotely 'clever' like an Optimate.. that does all sorts of things to the battery before it starts normal charging and afterwards. Any kind of charger like that.. the sort that you connect and leave on for weeks or months will kill it. As will any charger that starts with a 'boost'.


I have an optimate for the GS. Im not going to be buying a charger for the Africa twin. no need to.

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Just to be clear, I have no issues with lithium batteries fitted to phones, drills, electric toothbrushes or bikes designed for them.

I was concerned with them being retro-fitted to bikes not designed for lithium batteries.

If the lithium batteries being sold to replace lead acid batteries in bikes are engineered to work safely in those bikes, then that's fine.

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If the lithium batteries being sold to replace lead acid batteries in bikes are engineered to work safely in those bikes, then that's fine.

 

for what its worth.. the battery in the Africa twin is a little over 4" x 4" x 3" - its tiny.


weighs 3lb and is much "stronger".. higher everything than the battery it replaced in the previous years bike.


As I mentioned.. standard size (replacement) batteries are mostly empty box. to match the originals.

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Also based on my experience of model aircraft batteries, I believe that it is very harmful to a Lithium ion battery to become fully discharged.

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Also based on my experience of model aircraft batteries, I believe that it is very harmful to a Lithium ion battery to become fully discharged.

 

I think its likely that that shouldnt happen.. and if it does, the battery is definitely faulty.


I would guess that the PMS (power management system) that is in all motorcyle lithium batteries will disable it when it reaches a certain level. effectively turning it off.

And.. for the OP that appears to me what has happened. the battery has turned off. so "nothing" no display and not even a 'click'.

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Also based on my experience of model aircraft batteries, I believe that it is very harmful to a Lithium ion battery to become fully discharged.

 

This is true. I accidentally totally discharged one of my lithium battery packs (well really it wasn't me, someone else discharged it and then left it on the bench for ages so that even with their very slow discharge rate it went below minimum voltage) - when I tried to charge it the charger just flashed a faulty battery code.


On the basis a £70 battery pack is now scrap I thought there's nothing to lose so I tried the old trick of putting a very low amp charge into it, same as I do with lead acids that are pancaked, and that seems to have done the trick. After a fairly short while the voltage went back to the point where the normal charger was able to take over.


I've no idea if it will hold the charge now, but I'll keep a close eye on it.

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  • 4 months later...

@Mississippi Bullfrog Did it recover ?

I use a few lithium powered things plus I'm fitting a Skyrich battery so I'm curious. TIA

 

So far, so good. Having got the voltage back up it took a full charge and has since worked fine. I have laid down the law not to leave them discharged in future.

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