Slow start-Battery voltage?

[Salishmoto]

So my Blue Beast has always started fine and I put a new battery in when I got her a few months ago. She charges right at 14.2 volts. The past couple days the bike has been very slow to start, with the battery barely able to turn over the crank. Last night I got home after riding home from work and checked the direct battery voltage and it was 13.2 soon a bit after shutting off the bike. This morning, I checked it again, and it was down to 12.73. That's not bad. But then the bike was again really, really sluggish to start. By sluggish I don't mean many cranks and won't fire. I mean, the battery is barely turning over the crank like it is a weak battery and can barely get the cylinders to cycle. At this slow pace, it still catches and fires up after just a few strokes but that's not normal.

I would think 12.73 is close enough to normal to not matter. Anyone have any experience with this? Thanks.

 

[gringo]

try jumping off another battery, if it cranks faster, it is probably your battery, if it's still slow it's somewhere in the wiring / starter
or check the voltage drop during cranking

 

[Salishmoto]

Good idea. Thanks.

 

[john zibell]

Also check and clean the ground behind the starter cover. It may be tight, but invisible corrosion can play havoc.

 

[Salishmoto]

Thanks John, I never would have thought of that. I've got a good plan of attack for when I get home from work tonight. I'll report back if I find anything obvious.

 

[Salishmoto]

Ok, got home from work and put my multimeter on the battery as I cranked her over and the battery dropped to 7-8 volts. No bueno. I'm ordering the Yuasa YTX 20 CH-BS based on recommendations. Thanks again for your insights. That darn Motobatts AGM didn't last three months. Piece of crap.

 

[john zibell]

Ok, got home from work and put my multimeter on the battery as I cranked her over and the battery dropped to 7-8 volts. No bueno. I'm ordering the Yuasa YTX 20 CH-BS based on recommendations. Thanks again for your insights. That darn Motobatts AGM didn't last three months. Piece of crap.

Or this from the store. https://gtmotocycles.com/collections/electronics/products/gtm-lithium-battery-20l Don't forget the charger https://gtmotocycles.com/collections/electronics/products/optimate-duo-1-agm-lithium-charger

 

[scottmastrocinque]

As I have written here exhaustively about this I will be brief.

Surface voltage really means diddly squat.

You need to load test a battery to tell it’s real condition and even better, find an auto parts store that has a digital battery load tester that reads internal plate resistance. That tells you what’s going on.

Sounds to me that your battery has one or more dead or dying cells.

AGM Battery technology is well proven and reliable and infinitely better than open lead acid batteries.

schweizerschrauber.ch/mot/batt.html

 

[jwtucker]

Also, if you're battery tender is an old model, it might not properly support newer AGM batteries. I had a battery on a relatively new bike die, and I kept it on the tender almost all the time. While I'm not positive this was the problem, after I started looking into it, I realized my ancient battery tender was not really up to the task anymore with AGM batteries, so it was time to replace it.

__Jason

 

[scottmastrocinque]

This is a point of disagreement between John Zibell and I. All my motorcycles, for the last 25 years, live on Battery Tender branded chargers.

All my batteries have survived ridiculous amounts of time. For example, I just recently replaced my 2012 Stelvio battery a month ago.

John’s experience has been the opposite, in that he has observed premature failure on batteries that are kept on tenders.

You have to make your own decision on this one gents.

 

[Moto-Uno]

Glad to see you had performed my favourite (quick and cheap) test by attaching your multimeter
to the battery terminals while cranking , 'cuz that's what's happening now to your bike . 3 months on
that battery should have no problem getting a warranty claim going . AGM batteries have been a
god send to motorcycles . Peter

 

[Lannis]

. AGM batteries have been a
god send to motorcycles . Peter

Yep. Battery technology has really lagged the rest of the neat things in the world. How many years was it necessary for us to carry essentially an open bucket of sulfuric acid under our butts, making fumes, spilling, generating explosive hydrogen, stripping off paint and chrome from the back half of your bike ....

My Ferguson tractor wouldn't start one day. I raised the hood, hit the button, and heard a little "snap". Aha, said I, one of the terminals is loose or corroded, and I can hear the spark. I'll bend down close so I can see which one. Hit the button, and the battery exploded - nothing left of it but about half of the lead plates and the base rubber bit; no sides or top. Luckily I had my work safety glasses on; the explosion knocked them off my face. My ears were ringing, but I could see that my T-shirt was starting to fall off of me. Ran like I didn't think I could run to the water hose and soaked myself down for a few minutes. No shirt left, and the pants full of holes.

I hate those things. AGM for me, even on the 60-year-old bikes.

Lannis

 

[scottmastrocinque]

Also, if you're battery tender is an old model, it might not properly support newer AGM batteries. I had a battery on a relatively new bike die, and I kept it on the tender almost all the time. While I'm not positive this was the problem, after I started looking into it, I realized my ancient battery tender was not really up to the task anymore with AGM batteries, so it was time to replace it.

__Jason

One last blurb about this topic.

Over the years, I have replaced many customer’s batteries that were kept on a Battery Tender. Specifically the itty-bitty 700mA version like this one. It’s just a little transformer you plug into the wall.

My opinion of this particular low amperage version is I give it a 2 / 10. I think it’s only suitable for vintage 400cc or smaller motorcycles with old lead acid technology, like the tiny Yuasa batteries.

For the most part, I think it sucks eggs and it’s 50-70% as expensive as a good model Battery Tender!

It’s just too puny to adequately maintain a AGM battery IN MY OPINION AND EXPERIENCE.

I have used the 4 Amp Battery Tenders ever since they became available 25 years ago, and I’ve never been let down or disappointed.

The 4 Amp has even resurrected fully discharged customer batteries for me.

The 700mA wouldn’t even turn on for that type of discharged battery.

 

[jwtucker]

I think the tender I had for years was a 700mA version.
I had the wife's V7III hooked up to that, and when I tried to start it in the spring, the battery was shot - dead cell. It could have been coincidental - I'm not even sure if the battery was great to begin with. The bike was purchased as NOS, and I'm not sure the battery in it was the OEM that the bike should have originally come with - or where it even came from.

At any rate, I trashed the old tender and switched to a new 2-bank Battery Tender Plus, which is 1.25A (but also can provide higher voltage, if I'm not mistaken, which may be better for AGM).

At any rate, I guess the moral of the story is that not all tenders are created equal.

__Jason

 

[scottmastrocinque]

All tenders are 12 Volts (although some are 6V to support old antique cars and motorcycles), it's the Amperage that is different.

 

[jwtucker]

All tenders are 12 Volts (although some are 6V to support old antique cars and motorcycles), it's the Amperage that is different.

They support 12 volt batteries, but that doesn't mean they put out 12 volts of course.

BTW, from the batterytender.com FAQ page:

RECHARGING AGM BATTERIES: The Battery Tender® has an absorption charge mode, but the the Battery Tender® Plus has a different absorption mode maximum charge voltage and a timer to hold the absorption voltage longer. These specific changes were made to accommodate the charging requirements of Absorbed Glass Mat (AGM) style lead acid batteries.

"different absorption mode maximum charge voltage". Granted, this may all just be marketing spiel, but they clearly seem to be saying that the voltage capabilities are in fact different on the newer "Plus" models.

__Jason

 

[Rusty2000]

Ok, got home from work and put my multimeter on the battery as I cranked her over and the battery dropped to 7-8 volts. No bueno. I'm ordering the Yuasa YTX 20 CH-BS based on recommendations. Thanks again for your insights. That darn Motobatts AGM didn't last three months. Piece of crap.

Motobatts are rubbish. I have had three in two years on two different bikes. Complete waste of money. Varta, Excide, Bosch or Yausa in future!

 

[V700Steve]

One of the last shops I worked at had to switch suppliers for the Yuasa's it was shipping that were damaging the batteries. It is not always the manufacturer.

 

[john zibell]

What helps to spin the engine is cold cranking amps. A weak battery will not perform as needed as Scott has said many times. A load test is the only way to see if the battery is performing as needed. A second issue could be current supplied. If connections have corrosion there is resistance that will impact current flow. A third issue is worn bearings in the starter. Start with the easy with a load test. Back in the early 70, I had a Chrysler with a 440 CU engine. With age, 12 volt batteries just would't perform well. I installed two large 6 volt batteries (there was space under the hood in those days) in series to improve cold cranking amps. More lead plates to store energy. Solved the issue. I've always believed in installing the largest CCA battery I can into a vehicle.