Hey Guys,

So I have a Shorai Lithium battery in my bike, and needed to replace it as it wouldn't take a charge anymore. So I installed a new one and went for an epic ride yesterday. The battery doesn't seem to be taking a charge, I really don't know what's up with it. After about 20 miles, I turned the bike off and was able to kick it over. After another 20+ miles or so more, I stopped for lunch, and upon coming back to the bike the headlight wouldn't even illuminate in the "on" key position. I was able to bump start it, and it ran just fine, but when I shut it off, the bike is basically dead. Any ideas on what I should be looking at? I have a feeling that my old battery was ok and this same thing happened and it drained so much that it wouldn't except a charge anymore. Thanks for any input.

Michael
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1993 NSR MC21 SE 1990 NSR MC21 SP

It seems your regulator has died.
Check that the voltaje is 12V and when your start it up goes to 14V if the voltaje does not rise you have charging problems.

Cheers.

I'm having battery issues too, must be this crazy weather we're getting here in L.A. HA!

Did you replace the Shorai with another Shorai? I've heard mix reviews on that brand of lithium battery. But like JaviNSR said, hook up a volt meter and see if the bike is charging and also not over charging.


Bryan

So I checked the voltage and it read 13.4 (seems a little high, I thought it should read about 12.5 to 12.7). When I fire up the bike (which fires up by kick start now that I recharged the battery), it only went up to 13.7. Seems like I may have a charging issue. The weird thing is, I thought this bike has a battery operated ignition, so I don't understand why when it won't kick over with the kick starter, and the lights won't even turn on with the key in the "ON" position, why it runs just fine when I bump start it. To me it would seem like the charging system is working if this is the case. Confused

Bryan, yes, I replaced my old Shorai with another Shorai.
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1993 NSR MC21 SE 1990 NSR MC21 SP

The output of the regulator should be higher than the battery voltage as it needs to 'shove' the charge into it.

When running it's clearly making enough to run the bike, but not enough to charge the battery.

There are plenty of forum threads about the charging system, so a search should throw up more information than you could possibly need!

It does sound like a regulator problem, especially if it has happened with a new battery. I had this before when battery actually ran down after a ride, when I read the voltage it went down instead of up when bike was running! Voltage does not sound to bad, but if you are only getting a small increase when running then its worth checking or swapping out the regulator as an easy first step

I couldn't help but wonder if you have a high wattage headlight that is perhaps at least partly responsible for your problems.
If the bulb is rated at more than about 45 or 55 Watts than you may want to downgrade the wattage.

Just throwing it out out there.
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[color=#808080][size=9]Yes,.. I too know how to waste Time and Money,...

or to put it another way:
It seems that everything is working fine and the problem is likely? a high drain element that is taking more than the generator can supply, leading to flat batteries.

Have you tried going for a run with a good battery and NOT using the headlight?

I personally am a bit of a fan of those Shorai batteries as they are very light weight.
However, it seems that the Amp-Hour rating stated for them is fairly optimistic.
In reality, closer to half of what is stated I suspect.
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[color=#808080][size=9]Yes,.. I too know how to waste Time and Money,...

According to the YUASA technical manual, a fully charged lead acid battery should have at least 12.8V 1-2 hrs. after charging has finished.
I have not found specs for lithium batteries.
When charging at around 5000 rpm, the battery voltage should be ~ 14.4 V- 15.4V.
The rectifier/regulator is an item that wears and there is no other remedy than replacing it "regularly". It gets very hot (I measured > 100°C on the surface of my RVF400 regulator), this wears the power electronics in the reg).

Thanks guys, I'm going to put a new regulator in and see if that solves the problem.

MEM wrote:Thanks guys, I'm going to put a new regulator in and see if that solves the problem.

I know it`s been quite some time but did the regulator get replaced and solve the problem ?

i just read this and thought of last thursday paul
exactly the same as what your battery did isnt it !
is your battery a shorai ?

mydogtaz wrote:

MEM wrote:Thanks guys, I'm going to put a new regulator in and see if that solves the problem.

I know it`s been quite some time but did the regulator get replaced and solve the problem ?

Yes, ended up getting a new regulator and all was fine.
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1993 NSR MC21 SE 1990 NSR MC21 SP

OK...............Thanks for that.

Just an update on my problems............After reading this thread I decided to point the guilty finger
at the rectifier........After seeing it advertised for sale (brand new) on a Dutch website for 260 Euros (Ouch)
I searched and found one (second hand) for sale on a Japanese auction site.........Won it with a bid of £15.00 + commision+P&P, arrived after 10 days..........Fitted it yesterday and YIPPEE !
Battery reads 12.7volts when idle and goes up to 14.1volts when the bike is running and with the lights on
It pays to read all the threads on here