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Generic Battery Tender overcharging battery?

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Hey guys, I picked up a couple of generic Battery Tenders from Harbor Freight to put on my DRZ and my girlfriend's Grom. I checked the voltage with them connected to the bikes and after ~24 hrs the Grom stays steady at about 13.2V. When I checked the DRZ, it was showing 14.35V. 

I let the bikes sit for a couple of days unplugged and swapped the Battery Tenders to opposite bikes, but still my DRZ seems to get overcharged.

I have a Genuine Battery Tender on one of my cars that I could try on the DRZ, but I first wanted to know if 14+ volt was normal? 

Thanks

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1 hour ago, Mike S said:

Hey guys, I picked up a couple of generic Battery Tenders from Harbor Freight to put on my DRZ and my girlfriend's Grom. I checked the voltage with them connected to the bikes and after ~24 hrs the Grom stays steady at about 13.2V. When I checked the DRZ, it was showing 14.35V. 

I let the bikes sit for a couple of days unplugged and swapped the Battery Tenders to opposite bikes, but still my DRZ seems to get overcharged.

I have a Genuine Battery Tender on one of my cars that I could try on the DRZ, but I first wanted to know if 14+ volt was normal? 

Thanks

Are you checking the voltage with the chargers hooked up, plugged in?

Let the battery sit a good hour with everything disconnected, the measure the voltage.

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Yeah I was checking the voltage with the Battery Tender connected to the battery. It just seemed really high to me. In my experience with charging batteries, I don't think I've ever seen one go over 13.6V while it was being charged.

I took the Battery Tender off of the bike last night and will check the voltage later today when I get home.

Thanks

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Hello Mike,

Maybe your battery is going bad. Long ago I used to work with lead acid batteries. And remember that they needed a higher charging voltage when they got aged. Charging was not automatic then.

You should check how your battery tender works: does it use voltage or current as a measure for the charging level? In the latter case, a bad battery will give you the higher values as noted.

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actually about 14.5 -15 is fully charged on the regular gel sealed lead batteries .. if the one tender is holding it at 14.3 or whatever thats about right .. 13.2 is kindof low, could be the bettery type in the grom or whatever .. personally i charge my bikes to ~14.5 and then leave them off the tender for a week, those cheap tenders can go bad and cause everything from fire to actual over-charging which will ruin the battery .. but 14.5 yeah, thats the sweet spot for the typical lead acid motorcycle battery ..

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I use an Optimate charger which has a tender mode, which I don't use.

I don't think lead acid batteries enjoy being float charged for long periods. I think it's better to give the battery a few hours charge every couple of weeks, but with an automatic charger that will regulate it properly and switch off when the battery is full (or at least default to float charge mode).

I have 3 bikes (5 here in total) and I keep them all topped up with just one charger.

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14 hours ago, cowpie said:

actually about 14.5 -15 is fully charged on the regular gel sealed lead batteries .. if the one tender is holding it at 14.3 or whatever thats about right .. 13.2 is kindof low, could be the bettery type in the grom or whatever .. personally i charge my bikes to ~14.5 and then leave them off the tender for a week, those cheap tenders can go bad and cause everything from fire to actual over-charging which will ruin the battery .. but 14.5 yeah, thats the sweet spot for the typical lead acid motorcycle battery ..

I think you are confusing voltages from running vehicles, and vehicles that are off. Very few batteries are "gel". The more popular types for motorcycles are AGM. There are actual gel batteries, but these should not be confused with AGM batteries.  12.5-12.8 volts is generally considered a full charge. I've found on some AGM batteries, some just end up as low as 12.2-12.5 is a full charge. With the bike running you are hoping for 14-14.9, but anything from 13-15 would charge the battery.

The other important thing to consider here is a regular lead acid battery, AGM battery, and a GEL battery all have different charge levels, and should be turned off at different points. This is why nicer chargers have different modes for the different batteries, or can "detect" which battery is connected.

The battery voltage maybe initially high too when connected to the charger (and charging), however disconnected from the charger, and sitting, what does it settle out to? Is this an automatic charger, will it turn off?

I leave both my bikes and my Jeep on chargers year round, but they sit on nice Optimate chargers. Just now replacing a seven year old battery in my R6. So you can leave them connected all the time, with a proper charger.

 

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10 hours ago, OhioYJ said:

I think you are confusing voltages from running vehicles, and vehicles that are off. Very few batteries are "gel". The more popular types for motorcycles are AGM. There are actual gel batteries, but these should not be confused with AGM batteries.  12.5-12.8 volts is generally considered a full charge. I've found on some AGM batteries, some just end up as low as 12.2-12.5 is a full charge. With the bike running you are hoping for 14-14.9, but anything from 13-15 would charge the battery.

The other important thing to consider here is a regular lead acid battery, AGM battery, and a GEL battery all have different charge levels, and should be turned off at different points. This is why nicer chargers have different modes for the different batteries, or can "detect" which battery is connected.

The battery voltage maybe initially high too when connected to the charger (and charging), however disconnected from the charger, and sitting, what does it settle out to? Is this an automatic charger, will it turn off?

I leave both my bikes and my Jeep on chargers year round, but they sit on nice Optimate chargers. Just now replacing a seven year old battery in my R6. So you can leave them connected all the time, with a proper charger.

 

no, im not confusing anything .. your right about the terminology as far as construction of the batteries but the label on the side that says fully charged at 14.5V@100-500ma rate is pretty self explanatory .. a typical tender trickles at that rate, so if you check it with a meter it should be bringing it to 14 to 15v if its not really cold temps .. so in this exmple the 14.3 or whatever it was is spot on and the ~13.2 is low for whatever reason, maybe battery type, im not familiar with the grom .. which is pretty much repeating everything i already said ..

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28 minutes ago, cowpie said:

no, im not confusing anything .. your right about the terminology as far as construction of the batteries but the label on the side that says fully charged at 14.5V@100-500ma rate is pretty self explanatory .. a typical tender trickles at that rate, so if you check it with a meter it should be bringing it to 14 to 15v if its not really cold temps .. so in this exmple the 14.3 or whatever it was is spot on and the ~13.2 is low for whatever reason, maybe battery type, im not familiar with the grom .. which is pretty much repeating everything i already said ..

 I would still say 14.5 is really high, and abnormal, this is charging voltage, not a normal at rest voltage.

Yuasa Battery Faq, states, fully charged normal voltage is 12.7 or higher.

Optima FAQ (I know car batteries), states, all starting batteries, like their red tops should be 12.6-12.8 volts fully charged.

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 I would still say 14.5 is really high, and abnormal, this is charging voltage, not a normal at rest voltage.
Yuasa Battery Faq, states, fully charged normal voltage is 12.7 or higher.
Optima FAQ (I know car batteries), states, all starting batteries, like their red tops should be 12.6-12.8 volts fully charged.
Cowpie was talking about on the charger. He knows it will settle to mid 12's after disconnected from charger for a while.
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9 hours ago, bucket list said:
10 hours ago, OhioYJ said:
 I would still say 14.5 is really high, and abnormal, this is charging voltage, not a normal at rest voltage.
Yuasa Battery Faq, states, fully charged normal voltage is 12.7 or higher.
Optima FAQ (I know car batteries), states, all starting batteries, like their red tops should be 12.6-12.8 volts fully charged.

Cowpie was talking about on the charger. He knows it will settle to mid 12's after disconnected from charger for a while.

Haha, reading comprehension fail on my part...

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Wow.  All these reponses....  So what is the voltage at now with the charger unplugged and disconnected. 

I wouldn't trust my house with cheap battery tender that stays plugged in.

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