AGM batteries and Battery Tenders

My ST has my first AGM battery. For years and years I have left my bikes (and the occasional car) connected to a Battery Tender (brand) or similar battery charge maintainer over the winter. At a recent rally, there was a lively discussion with a couple of fellows saying that Battery Tenders were too 'hot' (voltage is too high) and that they would 'cook' an AGM battery dry if left connected over the winter. In the past, with standard type batteries, I checked the electrolyte level when I put the bike away and again in the spring, topping up with distilled water if necessary. Obviously AGM batteries don't do electrolyte topping up.

Here I thought AGM batteries were basically lead/acid batteries and are treated the same as your standard old style l/a battery. What is the correct way to deal with my AGM - the bike is stored from first snowfall (November sometimes) through end of Salt (April or May).

You can bulk charge an AGM at a full 14.4 volts (2.4 volts per cell), but they're more sensitive to overcharging than flooded batteries and can't be kept at that voltage once fully charged. When you go to float, 13.2-13.8 volts (2.2-2.3 volts per cell) is fine.

Deltran-branded Battery Tenders float at no more than 0.6V above the battery's resting voltage, which for most is 12.6 volts, which will put you at the bottom of the safe range. If you're using one of these or a charger that does the same, connect it up, turn it on and have a good winter.

Chargers that don't have a float mode will toast your battery, and that's why you wouldn't use them for anything but bulk charging.


--Mark

Sorry, can't help you with your problem as I never owned a battery tender. My battery has lasted 5 years and I just put a new one in this year in January.
I do have a charger, I might hook it up for a day once during the winter if the bike sits for say a month.
I ride year round, snow might stop me for a week or so.
Point is, I hear horror stories with battery tenders, so I choose not to use them and my battery still lasts.

All year long, 3 bikes with AGM, always plugged in (Deltran Jr). Always ready to go, never a problem. No more need to take them indoors for winter, or do anything else.

I have a car and 2 Bikes with AGM's in them now.
I put the battery trickel charger on them about once a month out of habit and with in 30 seconds or less I get a green all charged up light. After a few months of this I thought this was pretty wild so I started reading up on AGM batteries.
What I found out is that they only lose about 1% of there charge per month. Wow, I am thinking this is great for any vehicle that sits for a couple of months.
I feel I can pretty much stow away my charger now.... I will most likely never buy anything less than a AGM Battery again.

SMSW said:

My ST has my first AGM battery. For years and years I have left my bikes (and the occasional car) connected to a Battery Tender (brand) or similar battery charge maintainer over the winter. At a recent rally, there was a lively discussion with a couple of fellows saying that Battery Tenders were too 'hot' (voltage is too high) and that they would 'cook' an AGM battery dry if left connected over the winter.

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The deltran battery tender is fine for your agm. I've watched it cycle (on the bench at room temperature) with a calibrated fluke.
If they were talking about a trickle charger I'd agree. Also a car charger isn't appropriate. Both deltrans are under 1/3C charge rate and back off voltage after bulk charge and top off. A 5amp car charger is pushing things with rate. I'd guess a cheapo 5-10amp car charger wouldn't be the best for ac ripple either.

1% self discharge is about the best you'd get and at cold temperatures and off the bike. It's also good to keep the battery 75%+ state of charge.
I've come across 3.5% at 77F and doubling every 20F as a ball park and varies with age.

SMSW said:

What is the correct way to deal with my AGM - the bike is stored from first snowfall (November sometimes) through end of Salt (April or May).

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I think that the key issue is to use a battery maintainer that is designed to be used with AGM batteries. I'm not as knowledgeable about electricity as others who have posted replies here, but my past experience with cars and aircraft that are fitted with AGM batteries is that either the vehicle / aircraft manufacturer or the battery manufacturer specifies that only a charger / maintainer designed for use with AGM batteries should be used.

To the best of my (little) knowledge, chargers designed for use with AGM batteries behave differently (switch off differently) when the attached battery reaches the end of the charge cycle.

Most battery maintainers sold in automotive supply shops today will have a switch that enables use with both AGM and conventional wet-cell lead acid batteries.

Michael

There is a lot of confusion between gel and AGM batteries. Gel batteries have the diluted acid electrolyte mixed with a thickening agent while AGM batteries have a conventional wet acid dilution soaked up by absorbent glass mat plates. Gel batteries require both a lower voltage current in the charging state and a lower float current to maintain them compared to old fashioned wet flooded batteries and AGMs. Gels require a different charge regime while AGMs will do just fine with chargers or tenders designed for wet flooded batteries as long as the charger does not let the charge voltage exceed 14.2 volts and the float voltage exceed 13.6 volts which all "smart chargers" are supposed to do. True gel batteries have all but disappeared in favor of AGMs because AGMs are easy to live with and can be charged and maintained easily.

Gels gained rapid popularity in the 90's when many if not most of us still had old fashioned ferroresonant chargers that would overheat and cook a gel battery in short order. No wonder - they allowed the charge voltage to exceed 15 or 16 volts. Those chargers would also do the same (overheat) to wet acid batteries but we were used to checking the acid level and adding water when necessary. When AGMs came along the stories of cooked gel batteries were fresh in people's mind and have carried over to AGMs. AGMs have cases and vents that recombine the gas created when charging so the wet electrolyte contained inside never needs topping up.

Anyway, solid state "smart chargers" used as tenders put out miniscule amounts of charge current and keep it under 13.6 volts and can be used just fine with AGM batteries. My experience was gained by selling all these types of batteries and chargers for 10 years and building and maintaining 12 volt battery banks in sailboats and trawlers.

Motorcycle batteries are uniformly small in size and do not need more than 1 or 2 amps of charge current.

My battery has a full charge, according to my battery tender, but the bike turns over REALLY slow in this cold weather. The lights are bright, everything looks good, but it seems to barely start. I am afraid to take it to work in this cold weather and come out at the end of the shift and not have enough juice to crank it over. Is it just because the motor is heavy and cold? Is this a common issue with the ST1300? Just curious if anyone else deals with this.

STimpa said:

My battery has a full charge, according to my battery tender, but the bike turns over REALLY slow in this cold weather. The lights are bright, everything looks good, but it seems to barely start. I am afraid to take it to work in this cold weather and come out at the end of the shift and not have enough juice to crank it over. Is it just because the motor is heavy and cold? Is this a common issue with the ST1300? Just curious if anyone else deals with this.

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I think you need to check the voltage of the battery before you try to start the bike and also during cranking. If the battery is really charged up, then i think you have a 'choke' point - a bad connection in the wiring or a bad ground and the starter is not getting the voltage and current it needs to spin. The starter relay might also be the problem.

Thanks for the suggestions. I had a friend do a load test on the battery and it looks good. I will check the connection to the starter and see where that leads.

STimpa said:

My battery has a full charge, according to my battery tender, but the bike turns over REALLY slow in this cold weather. The lights are bright, everything looks good, but it seems to barely start. I am afraid to take it to work in this cold weather and come out at the end of the shift and not have enough juice to crank it over. Is it just because the motor is heavy and cold? Is this a common issue with the ST1300? Just curious if anyone else deals with this.

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I don't have this problem because I don't take the bike out in winter with all the salt and brine and who knows what that they put on the roads around here. But, as with any car, if you use the recommended oil the bike should turn over smartly - unless it is incredibly cold. Check the battery voltage when cranking with a good voltmeter as suggested in other threads here. I think you have high resistance somewhere - maybe at the starter terminals?

STimpa said:

My battery has a full charge, according to my battery tender, but the bike turns over REALLY slow in this cold weather. The lights are bright, everything looks good, but it seems to barely start. I am afraid to take it to work in this cold weather and come out at the end of the shift and not have enough juice to crank it over. Is it just because the motor is heavy and cold? Is this a common issue with the ST1300? Just curious if anyone else deals with this.

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This IS a common issue with ST1300s. That battery compartment is just too small; it is much smaller than that of a ST1100. I never had a cranking issue with my ST1100s in 12 years. My ST1300, on the other hand, has had multiple low battery issues due to inadequate capacity from Yuasa and Scorpion batteries. So far, the best AGM battery I have found for this bike is this one with 230 CCA, it will last about three years here in the hot South:

http://www.batteryweb.com/motorcycle-batteries-detail.cfm?model=PTZ14S

If you are wanting to start her up consistently in cold weather, stay with AGM. Otherwise, my buddies who ride sport bikes, in warm weather, like lithium batteries, which is what my Ducati is getting when the time comes.

AGM batteries have been standard equipment on Hondas since the early 1990s, so there really shouldn't be a lot of incompatible chargers out there any more.

The ST1300 battery compartment size does limit battery choices.

Ciao,

JZH said:

The ST1300 battery compartment size does limit battery choices.

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Yep. After seeing the mod that put saddle bags on the front of the ST I wonder how tough it would be to make a slightly larger cover for the battery side and then put in a larger mounting bracket and battery.

It would add some weight at the end of the day but I'd call it an acceptable tradeoff. And fans of Li-Fe etc would never notice. Such a mod would probably sell better than the rear cover panels did.

jmcarruth said:

This IS a common issue with ST1300s. That battery compartment is just too small; it is much smaller than that of a ST1100. I never had a cranking issue with my ST1100s in 12 years. My ST1300, on the other hand, has had multiple low battery issues due to inadequate capacity from Yuasa and Scorpion batteries. So far, the best AGM battery I have found for this bike is this one with 230 CCA, it will last about three years here in the hot South:

http://www.batteryweb.com/motorcycle-batteries-detail.cfm?model=PTZ14S

If you are wanting to start her up consistently in cold weather, stay with AGM. Otherwise, my buddies who ride sport bikes, in warm weather, like lithium batteries, which is what my Ducati is getting when the time comes.

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I ordered another Scorpion (the 230 cca) and installed it. Life is back to normal. I was told by a knowledgeable friend, that a battery can be fully charged but lose it's load capacity. I am a little disappointed in the AGM, in that it lasted just 3 seasons, while the OEM Yuasa made it 5 complete seasons.

Of course, there is always the reality that the ST1300 never does spin over like other bikes, even with a fresh battery. But like you say... the compartment is quite small.

Thanks for the tips.

STimpa said:

I ordered another Scorpion (the 230 cca) and installed it. Life is back to normal. I was told by a knowledgeable friend, that a battery can be fully charged but lose it's load capacity. I am a little disappointed in the AGM, in that it lasted just 3 seasons, while the OEM Yuasa made it 5 complete seasons.

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Glad you got it sorted out. Yeah that's the reason for a load test. The resting voltage gives you an indication of state of charge. The load test measure ability to deliver power. IOW the battery in effect gets smaller as it ages.
fwiw the yuasa is an AGM.

st1300r said:

fwiw the yuasa is an AGM.

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Hmmm, When I looked at getting one from the dealer (trying to support them, if the price was close) and was told the OEM had only 120 cca. With that, I decided on the Scorpion for the cca diff. Interesting that the OEM lasted much longer... just good luck?

STimpa said:

When I looked at getting one from the dealer (trying to support them, if the price was close) and was told the OEM had only 120 cca.

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Not sure where that came from, 'cause 120 would be awfully wheezy. Yuasa's data sheet says 230.

Interesting that the OEM lasted much longer... just good luck?

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Might be a higher-quality battery. I'm not entirely convinced that the OEM battery and the YTZ-14S you buy from Yuasa distributors is the same unit.

--Mark

Some of the aftermarket replacements listed 190cca. 120 had to be looking at the wrong line in their data book for a different battery.
The oem has white silk screen on it and lists 230cca 11.8Ahr at 20hr rate 11.2Ahr at a 10hr rate.
fwiw quick charge is listed at 5.5A normal charge is spec'd at 1.1A current.

Some replacement yuasa I've seen have a red silk screen. No idea what that means but a number of people report less service life from the replacement yuasa vs the oem original.

http://www.yuasabatteries.com/pdfs/Yuasa_Specs_Apps_2015.pdf