LiFePo4 batteries on old bikes?

[Mike.Gayner]

Does anyone know anything about using LiFePo4 batteries (Shorai et al) on old bikes? I don't know a whole lot about charging systems - would my A7 put out sufficient voltage to keep it balanced? I like the idea of shaving off a huge amount of weight and freeing up some space in the batt box.

[AllanB]

Excellent post mate! I'll check in later

[Mike.Gayner]

Huh, yeah I kind of know where this is going, trying to avoid the BS by posting in this sub-forum. That other thread makes me want to vomit. I'm up to page 8 of this thread, which is interesting but doesn't tell me much about how I can expect these batteries to perform in an old bike with an old charging system.

[tigertim20]

Im sure someone will b along to EDucate you shortly . . .

[pete376403]

Chance are the A7 puts out too much, rather than not enough volts, and that it relies on a pretty crude regulator to bleed off the excess as heat. eg my old Suzuki (Suzi must have made the worst of the jap electrics, but the others weren't much better) puts out about 70v AC on each of the three phases around 5000rpm and a basic rectifier/regulator is all that prevents a battery meltdown.

However as others have said Ed will be along shortly...

[bogan]

Voltage can be checked pretty easily with a voltmeter. Some batts self balance even on lower supply voltage; otherwise you can use a balance charger to do it yourself periodically. If it is higher than recommended, don't throw an LiFePo4 in there.

Some have had issues with the shunt type reg/rects (if that's what you have) and the LiFePo4's increased ability to 'draw' current from them. The potential is that if the battery is discharged significantly, it can draw more current than the reg/rect is designed to output, resulting in its failure, which can in turn pass too high a voltage to the battery and cause it to fail also. So imo you should look at adding in a charge fuse if your bike doesn't have one, just as an extra precaution.

[avgas]

Chance are the A7 puts out too much, rather than not enough volts, and that it relies on a pretty crude regulator to bleed off the excess as heat. eg my old Suzuki (Suzi must have made the worst of the jap electrics, but the others weren't much better) puts out about 70v AC on each of the three phases around 5000rpm and a basic rectifier/regulator is all that prevents a battery meltdown.

However as others have said Ed will be along shortly...

Interesting. But not that useful. What is the voltage AT the battery when the bike is running. Most of my work on the post-69 bikes the charging voltages never went above 14.5V.
I would be supprised if it exceeded the 15.5V that Ed keeps spouting about.

Oh and 70's isn't old.

But now I am curious.......who the hell things that removing the battery from an A7 saves weight????? Just cut of the rear mud-guard and save a ton

[Pussy]

I would chuck a nice new Yuasa in it...

[skippa1]

Does anyone know anything about using LiFePo4 batteries (Shorai et al) on old bikes? I don't know a whole lot about charging systems - would my A7 put out sufficient voltage to keep it balanced? I like the idea of shaving off a huge amount of weight and freeing up some space in the batt box.

Why would you? If the experts (salesmen) can't even give a straight answer, and lead acid has done the job all these years, I can't see the advantage

[Mike.Gayner]

Why would you? If the experts (salesmen) can't even give a straight answer, and lead acid has done the job all these years, I can't see the advantage

That's kind of a silly answer though. Using that logic, every new bike would be sold without electric starters, using old style sealed beam lights and why would we bother with fuel injection? Technology moves on, and the old "why change what's working" is a juvenile perspective when there are better options. If the batteries are objectively better (maybe they are, maybe they aren't) then why not use them? Smaller, lighter, longer lifespan (maybe) etc.

I'm just after information, I didn't think everyone was going to get their petticoats in a twist about it.

[skippa1]

That's kind of a silly answer though. Using that logic, every new bike would be sold without electric starters, using old style sealed beam lights and why would we bother with fuel injection? Technology moves on, and the old "why change what's working" is a juvenile perspective when there are better options. If the batteries are objectively better (maybe they are, maybe they aren't) then why not use them? Smaller, lighter, longer lifespan (maybe) etc.

I'm just after information, I didn't think everyone was going to get their petticoats in a twist about it.

Petticoats fine thanks, I just happen to agree with Pussys reply.

If you want a sensible answer, KB is the wrong place to ask, and the other thread clearly demonstrates that the self proclaimed experts can't agree so how are the rest of us going to? Silly? Juvenile? You bet, it's KB?

if you want new technology, why are you riding an old bike?

seriously though, if you haven't read the Shorai thread, read it. You will come away with only one certainty, lead acid is a reasonable price, reasonable life and you know what you're getting.

get whatever you want

[AllanB]

Skippa1 has a point - chuck in a Motobatt or similar - updated old school technology (sealed unit, gel matt internals) at a affordable price.

[Mike.Gayner]

if you want new technology, why are you riding an old bike?

If there's something simple you can replace, like a battery, that is objectively better, you'd be silly not to.

I'll take your advice - next time I have a question I won't bother with the self proclaimed KB experts, seeing as everyone here seems to approach online discussion like they're trying to start an argument.

[bogan]

If there's something simple you can replace, like a battery, that is objectively better, you'd be silly not to.

I'll take your advice - next time I have a question I won't bother with the self proclaimed KB experts, seeing as everyone here seems to approach online discussion like they're trying to start an argument.

Have you figured out the current charging voltage and reg type yet?

Perhaps your focus on the perceived argument has been somewhat contributory to the lack of information gleaned... don't let the BS stop you from being an early adopter, it'll go that way eventually (barring materials shortage or other rapid batt development). They are objectively better than lead acid, but getting an objective brand comparison between LiFePO4s is quite a task.

[Madness]

I'll take your advice - next time I have a question I won't bother with the self proclaimed KB experts, seeing as everyone here seems to approach online discussion like they're trying to start an argument.

Someone rather clever once typed: KiwiBiker, full of love and disrespect.