Interpreting My Quick Test

[bccap]

Yesterday I had an experience at a Stealership. I had gotten the bike out from hibernation and taken it out to gas it up. After I filled it up I noticed that it slow cranked before it started. I knew the battery was on it's last legs so swung by the Stealership to pick up a new one. They did a quick check of my system and said I'm only getting 7 volts max and tried to get me to leave it for repair. I know these guys pretty well so wasn't going to fall for that but to not get stranded going home paid them $110 to truck it home for me in case I was just running off the battery. Went down and did my own quick test. 12.6 key off. 12.2 key on. Then varying results at different revs. but basically 14 to 14.4 volts across the board. Even at idle 1500 revs I got 13.8 to 14.2 at times. I know I need a battery but are these readings anything I should be concerned about ? They're a little higher at idle then the quick test says they should be.

[Redman]

........... I knew the battery was on it's last legs so swung by the Stealership to pick up a new one. .........
............

Ew.. No Need for that, unless you are going out of you way to support the dealership.
Can get what you need at autoparts store (most carry mo'ckl batterys).

.
.............did my own quick test. 12.6 key off. 12.2 key on. .................

If battery at 12.6, the charging must have been running to keep it there. If charging not working then the voltage would keep going lower and lower.

That is a bit of a drop when turn things on (add load to the battery), but not much .... inconclusive. Does it drop much more after a minute or so....?

..............................Then varying results at different revs. but basically 14 to 14.4 volts across the board. Even at idle 1500 revs I got 13.8 to 14.2 at times............

That is not bad, some folks might think it should be higher on a more modern bike, but that 14 to 14.4 shows the charging is working (not completely failed anyway). Is higher than battery voltage when engine off, so the charging system is charging.


What symptom are you seeing to say battery on last leggs....? The slow cranking after long time storage....?
Was the battery on a batterry tender? If not, well, then, yah, I would expect it to crank slow then.


I wonder if they meant the volts drop to 7 volts when cranking. Which could happen if battery not well charged.


See how it goes after riding at speed for a while, or try charging battery with a small charger.

[bccap]

Ew.. No Need for that, unless you are going out of you way to support the dealership.
Can get what you need at autoparts store (most carry mo'ckl batterys).



If battery at 12.6, the charging must have been running to keep it there. If charging not working then the voltage would keep going lower and lower.

That is a bit of a drop when turn things on (add load to the battery), but not much .... inconclusive. Does it drop much more after a minute or so....?






That is not bad, some folks might think it should be higher on a more modern bike, but that 14 to 14.4 shows the charging is working (not completely failed anyway). Is higher than battery voltage when engine off, so the charging system is charging.


What symptom are you seeing to say battery on last leggs....? The slow cranking after long time storage....?
Was the battery on a batterry tender? If not, well, then, yah, I would expect it to crank slow then.


I wonder if they meant the volts drop when cranking. Which could expect if battery not well charged.


See how it goes after riding at speed for a while, or try charging battery with a small charger.

It's seven years old and when I first got it I boiled it dry from a bad R/R that was putting out 17.5 volts so I didn't expect it to last long. I've noticed lately that it won't hold a charge for longer than a few days and changes to cranking slowly in a short period of time after I charge it. I don't know how to " load test it " but am pretty sure it's toast. I didn't check the battery again after it had been off for a minute or so. I was just concerned that the voltage should be a little lower when at an idle.....

[bccap]

I wonder if they meant the volts drop to 7 volts when cranking. Which could happen if battery not well charged..

No I watched them do it. They had some weird very cheap looking meter and it showed 7 volts at 5000 rpm. These guys have more complaints at the Better Business Bureau than there are pubs in Vancouver. But the one thing they do have going for them is parts are relatively reasonably priced.

[Redman]

It's seven years old " ...................

Oh.... Yah..... Okay.... That pretty much tells the story.

............................................... I've noticed lately that it won't hold a charge for longer than a few days and changes to cranking slowly in a short period of time after I charge it. I don't know how to " load test it " ...................

Good description of the symptoms of that thing in your battery box not being much of a battery.

Load test: Measure volts at no load (key off). Measure volts with a low load on it (key on so lights on), should drop only a little and be able to hold that for a couple minute or so. THen measure volts at the load it needs to operate at (running starter motor) and not drop much below, say, 11 or 10 volts (not really sure).

........... ............ ................ .......... ........ I was just concerned that the voltage should be a little lower when at an idle.....

Yes, voltage will go lower at idle because the charging system not put out much at idle. I too suspected what you said about "idle to 1500", but that is beside the point of the main problem. May need to let it idle for a bit.

[gsrick]

Sounds like your charging system is working fine, Garth. I'm not sure what they did to get only 7 volts with it running at 5k, if your getting 14.4v at the same rpm. I would just go ahead and purchase a new battery. If you got 7 years out of it, put it to pasture and let it have a rest as it went above and beyond the call of duty.

[bccap]

Thanks Rick and Redman. I'll replace it and see how it goes. I should do the mod from the stator to the R/R while I'm at it.......

[Redman]

..............I'll replace it and see how it goes. ........

Good. I think that is all you needed all along.
THe quick test mostly just checks of charging sytem is working, yes or no.
Could also do the further test of checking voltage at mid rpms and high rpms.

When getting the replacement battery; If need to do any cross referencing on the battery, or if just comparing physical size and amp-hour rating... dont overlook which terminal is + and which is -. THere are some that are opposite of what you need.

.

[bccap]

Good. I think that is all you needed all along.
THe quick test mostly just checks of charging sytem is working, yes or no.
Could also do the further test of checking voltage at mid rpms and high rpms.

When getting the replacement battery; If need to do any cross referencing on the battery, or if just comparing physical size and amp-hour rating... dont overlook which terminal is + and which is -. THere are some that are opposite of what you need.

.

Thanks. I'll keep an eye on the orientation of the terminals......

[Kiwi Canuck]

Garth, you can use my company account at Edmonds Batteries. You will get our discount and you can pay cash or CC.

Usually around $65- $75 for a motorcycle battery there.

David

[Steve]

And make sure you don't get a "wet" or "flooded cell" battery. Get an AGM battery.
Note that is a construction style, not a brand name.

.

[solarae]

7 volts on a 12v battery is stone dead. Something is fishy here.

[BigD_83]

I think the others are correct, Garth. If that 7V is what is registering when cranking it is toast. +1 on the absorbed glass mat battery. I will never go back to a wet cell if I have the choice.

Does this mean you are going to be riding more this season?

[leftlostcommonsense]

I do not mean to offend in any way, I'm just confused you went to the stealership for a battery, didn't get one because they said your battery was dead but still payed them 110 to haul your bike home? I mean didn't you say you drove the bike there on the bad battery? Wouldn't a new one have gotten you home? My friend I wouldn't go back there they did some jedi mind trick stuff on ya lol.

[bccap]

I do not mean to offend in any way, I'm just confused you went to the stealership for a battery, didn't get one because they said your battery was dead but still payed them 110 to haul your bike home? I mean didn't you say you drove the bike there on the bad battery? Wouldn't a new one have gotten you home? My friend I wouldn't go back there they did some jedi mind trick stuff on ya lol.

I would have to have waited for the new battery to be fully charged if I was going to rely on it alone to get me home as I was assuming their meter readings were correct. For medical reasons I'm not that strong right now and there is no way I could have pushed the bike more than a few feet to get it off the road had the battery run out of juice on the way home. The area between my home and the shop is the downtown core so you can't just pull to the side of the road and leave it for a while. I didn't think it was prudent to take the chance.......