Voltage at Battery

prue1

prue1

XS650 Addict
Messages
148
Reaction score
85
Points
28
Location
port st. lucie,fl
Hi Guys, my 72 XS2 continues to have battery (premature failure) issues. I always use a battery tender between rides. My last battery (AGM Motoblat) lasted two months. I get a maximum of 14.3 - 14.5 of volts at the battery at around 5000rpm with the lights off. With the lights on, the most voltage I get is 13.9. I'm thinking this isn't enough with the lights on? I have a first generation Pamco ignition and XS charge alternator. My rides are a maximum 20-40 miles at a time and I like to cruise at 3200 rpm - 4000 rpm. Maybe I should be increasing my rpm? Any ideas on how to increase my voltage with lights on?

Also, some may remember I posted a question on my leaky float/stripped screws, I hope to get after that project soon!

As always, I appreciate the feedback.
 
prue1 said:
Hi Guys, my 72 XS2 continues to have battery (premature failure) issues. I always use a battery tender between rides. My last battery (AGM Motoblat) lasted two months. I get a maximum of 14.3 - 14.5 of volts at the battery at around 5000rpm with the lights off. With the lights on, the most voltage I get is 13.9. I'm thinking this isn't enough with the lights on? I have a first generation Pamco ignition and XS charge alternator. My rides are a maximum 20-40 miles at a time and I like to cruise at 3200 rpm - 4000 rpm. Maybe I should be increasing my rpm? Any ideas on how to increase my voltage with lights on?
.
Click to expand...

Hi prue,
your Voltage numbers look to be OK. I'd suspect that your batteries are being shaken to death.
Check the battery holder's rubber mounts to be sure they are cushioning it properly
 
If not due to vibration then could be too much load on the battery ...

If you have an H4 headlight then I suggest decreasing from 55/60W to a 35/35W bulb. I used to get problems from the high Wattage headlight. The rev range you are in isn't an issue, neither is the length of trip. Most of my trips are 20 - 40 miles. I would aim to have 14.3 - 14.5 Volts by 2000rpm.

Some say batteries should not be permanently on tender. I do not know if this is true??? I run my tender on a timer switch for 2 hours each day and have not encountered any battery issues in five years.
 
Paul Sutton said:
If not due to vibration then could be too much load on the battery ...

If you have an H4 headlight then I suggest decreasing from 55/60W to a 35/35W bulb. I used to get problems from the high Wattage headlight. The rev range you are in isn't an issue, neither is the length of trip. Most of my trips are 20 - 40 miles. I would aim to have 14.3 - 14.5 Volts by 2000rpm.

Some say batteries should not be permanently on tender. I do not know if this is true??? I run my tender on a timer switch for 2 hours each day and have not encountered any battery issues in five years.
Click to expand...


I do have an H4 headlight, I'll check the wattage, thanks.
 
I never had luck with agm batteries. I got a conventional yuasa and have no problem now.

Edit- The rpm and ride length is fine. How often do you ride? If your riding a few times a week I think the tender is overkill, even if you ride once a week or less unless your putting the bike up for weeks at a time I wouldn't use the tender. Even then I would check and if needed maybe put it on a few hrs.
 
Last edited:
joebgd said:
I never had luck with agm batteries. I got a conventional yuasa and have no problem now.

Edit- The rpm and ride length is fine. How often do you ride? If your riding a few times a week I think the tender is overkill, even if you ride once a week or less unless your putting the bike up for weeks at a time I wouldn't use the tender. Even then I would check and if needed maybe put it on a few hrs.
Click to expand...


I usually ride once a week. What # Yuasa battery do you use? I have had no luck with getting one for my 72. I did have a conventional battery in for over a year, but neglected keeping the water levels up, maybe I will need to go back to the conventional battery. Thanks.
 
If I remember it is ybl12 14ah. I'll look it up. I've been riding ab once a week lately 30-50 mi. It's holding it's voltage at an 12.6 cranks the e start no prob and my #s are like yours as far as alternator.

Edit- yb14-la2
Here is a thread, I was going back and forth if I should get lion or lead acid. Wound up w the later and no regrets.

http://www.xs650.com/threads/battery-decision.57946/
 
Throw out that battery tender. Like joebgd sez only when needed then only for a day or so, then unplug. I've seen countless guys ruin batteries with tenders. I let my bikes sit all winter with one or two tender sessions of a day each, all good. No tender in the summer.
 
Last edited:
I rarely charge a battery. I take the bike for a ride. If I can't, I may charge the battery with a conventional motorcycle battery charger. That might be after 9 months of sitting. Yes, AGM for me. In the bikes, in the lawn mower, and in the car! They typically last seven years. I need to replace the one in my wife's car, because it's 9 years old and I prefer not wait for it to go dead.
 
Your '72 probably takes a different battery than the 14AH one joebgd uses in his later model. I think it's a little smaller so the later battery wouldn't fit. Parts diagram says it's a 12N12A-4A-1.

https://www.yuasabatteries.com/battery/12n12a-4a-1/

Like Gary, I rarely use the charger over the summer, and only once or twice over the winter storage period. I never hook a tender up and just leave it. I've had too many of them go bad on me over the years. And it usually wasn't because they stopped charging, just the opposite. They would never indicate full charge so would keep charging.
 
For what it's worth, I've installed 55/60W H-4's on pretty much every bike I've ever owned and never experienced charging or battery problems because of it. I have them on both my 650s and the charging output is fine once the revs are up. Granted, output is low at idle, but it's never seemed to cause any issues like the battery going dead. The bikes don't sit there idling for very long or very often, and the batteries seem to take it in stride, providing the ignition with extra voltage if need be.

In fact, while I still had the original mechanical regulator on my '78, it wasn't adjusted correctly and only put out high 13's max. Once I discovered this, and discovered you could adjust the regulator output, I turned it up, but I never had battery issues while it wasn't putting out the optimal low to mid 14's.

Do you have a voltmeter on the bike so you can monitor the output all the time? Maybe it's not putting out what it needs to all the time, or maybe it's spiking high sometimes. Also, sometimes you just get a bum battery that doesn't last long. Maybe you've been unlucky and got a few bad ones in a row.
 
regulator operation early.jpg


Early regulator adjustment 001.JPG


Early alternator generic schematic.gif
 
Last edited:
Here's more detailed instructions .....

QMb3A1k.jpg


On mine, I didn't even need to do any adjusting, just set the gaps (they were off). That made the output good again. You may need to fiddle with it some because, as mentioned above, putting the cover back on reduces the output a little.
 

Similar threads

ebbaga
XS650F misfire between 4000 and 5000 RPM. Boyer ignition.
Replies
3
Views
363
Raymond
Raymond
D
Headlight Voltage Drops
2 3
Replies
58
Views
4K
gggGary
gggGary
R
Could my coil drain my battery, why?
2 3 4
Replies
61
Views
4K
Rook32432
R
B
No Start - Voltage Drop While Cranking
2 3 4
Replies
68
Views
4K
Jim
Jim
P
Poor battery charging, next steps?
2
Replies
32
Views
1K
Kevin Werner
Kevin Werner
Back
Top