Battery Tender Jr question

[Chris338378]

I bought a Battery Tender Junior on Sunday to charge my flasher battery.  I put the charger on the battery which was at room temperature for a day and left it plugged in.  Whenever I went past the charger I checked the light on it and it was steady green indicating that it was fully charged.  Today I decided to see if the light on the charger that came with it turned green or stayed red since according to the Battery Tender it was fully charged.  The factor charger's light turned red so I then disconnected it and put the Battery Tender Junior back on the battery and it was flashing green, which according to the owner's manual indicates it's over 80% charged, and turned solid green in about fifteen minutes.  My questions are is that normal and do you think the battery is on it's way out?  I know the right way to check it is to use a volt meter but I don't have one. 

[3300]

how old is it and do you use it a lot? marcum says to replace every three years. they only cost 20$. do you try to keep a top charge on it in the off season? it's a good thing to do for them.
you can get a free dvm from harbor freight or spend 6$ for it and know more. it should stay 12.5 with a light load on it for over one hour and closer to two. the load would be your sonar.

[Chris338378]

I"m guessing you mean the flasher. the battery is just about five years old, I use it three or four times a day for about six to eight hours, and charge it during the off season once a month.  I'm not sure what you mean when you said, "they only cost 20$ you can get a free dvm from harbor freight or spend 6$ for it and know more".

[3300]

i wanted to know about the age and use of the battery. that was your concern i thought. so it sounds like it's worn out for sure.

the dvm is free with a coupon or 6$ otherwise.
it will tell you more about the battery, but it is not a load tester like we use on automotive batteries to indicate how far along it is to be being shot or worn out.
use your sonar to put a load on your battery and measure it. it should be 12.5 volts and stay there for a bout an hour or two with no charger on it.
the 20$ is for a new battery and should be replaced every 3 years if used a lot. the type of charger and if you keep it top charged in the off season helps it last longer. some say they get 5 years, but they don't hold the same charge as they did new. if your not getting your normal run time from it, it's time for a new battery is all.

[Chris338378]

Oh ok, I understand what you mean now.  I'll have to get a meter but won't be able to until the weekend on the way to go fishing.  What do you think based on what the Battery Tender Junior did?  I know it's no where near the level of information the meter will tell, I'd rather not buy a battery if I don't really have to.

[iceman260]

Five year old battery, replace it, you got the max out of it.

[3300]

smart chargers use different sample rates between brands and time frame rates to achieve their goals and they have several goals while charging. some are smarter than others. the more you pay the better it is holds true more times than not. so the free charger that came with the sonar or the after market designed to be in more households will be much different in build quality. more complex circuits and parts and semi-conductors would be used on better chargers. i am not saying the battery tender jr is the best, but it's good enough to get away from the free charger that comes with sonars. you can buy much better chargers, but it comes down to how many charges and how long those last per battery in the long run. sla has a limited amount of full charge cycles just like any other battery does. the end of life on them means short run times to not taking a charge. we give it up during the short run times tho.

the sample rates and the charge rates and the amount of time it use per step will be different too. also after it's charged, how they keep the float charge going to it will be different. so switching between them should have different readings to try to answer your question about the chargers.
the idea is to make it charge as slow as it can but not over charge them. the more you try to do this the harder it is for the circuit to detect the peak voltage. over charging hurts them the most. meaning too many volts for too long of a time period. kind of like cooking food to be perfect each time.

[Chris338378]

Ok that makes sense.

[sinneD]

I have found that if the battery is REALLY dead, the Battery Tender will not charge from too low a voltage. I suspect that the charging circuit is looking to maintain charge, not build it.

This seems to happen the most with my older batteries. I start their charge with a regular trickle charger then it works fine.

[SpitzoMT]

I have found that if the battery is REALLY dead, the Battery Tender will not charge from too low a voltage. I suspect that the charging circuit is looking to maintain charge, not build it.

This seems to happen the most with my older batteries. I start their charge with a regular trickle charger then it works fine.

Well said..........this is my experience as well !!

[Knife2sharp]

I couldn't tell from your post, but did you unplug the Battery Tender Jr after you noticed it was charged, or did you leave it on?  I have the same charger and can't remember if it goes into trickle charge mode when charged, or it stops charging.  Once it reaches the solid green state it may stop charging and if the battery starts dropping voltage, the charger may not reset until it's unplugged and plugged back in. I think you have a bad battery, it's not charging to peak, which should be above 13 volts, 13.4 - 13.8, and it's not holding that charge.  I found these lead acid batteries are very fickle and I gotten ones that are junk after a year or two.  The DeWalt batteries for my drill are tough and I don't use my drill a lot either, the hold their charge, I charge them when they drain or I throw one on the charger to top it off.  My drill is several years old and the two batteries are just let new.  But they're more expensive, but if they made these 12v I'd spend it.

[Chris338378]

I left the charger on the battery and plugged into the wall and the only time I took it off was when I decided to see if the light on the factory charger would turn green since the Battery Tender Jr was saying it was charged.  After I did that I put the Battery Tender Jr back on it and that's when I noticed the light started blinking green and after about 15 minutes it went back to solid green.  These chargers will charge the battery and then start charging again if the battery looses power.

[DR.SPECKLER]

I left the charger on the battery and plugged into the wall and the only time I took it off was when I decided to see if the light on the factory charger would turn green since the Battery Tender Jr was saying it was charged.  After I did that I put the Battery Tender Jr back on it and that's when I noticed the light started blinking green and after about 15 minutes it went back to solid green.  These chargers will charge the battery and then start charging again if the battery looses power.

yes the battery tender is a charger/maintainer.it charges the battery and the switches to float/maintain mode.if the charger reads voltage drop it switches back to charge mode,safe to leave on the battery without overcharging.sound like your old battery is discharging pretty quick.if your other charger is a Marcum one I wouldn't trust it.they are junk.

[Chris338378]

Yeah the other charger is a Marcum which is why I'm wondering if the battery really is going bad or if the charger just didn't charge the battery. 

[Chris338378]

I borrowed my friend's volt meter and checked the battery last night.  Turned out that after a "full charge" based on the Battery Tender's light turning solid green the battery had just under 12 volts  so I got a new one today.  I charged that on up and it was reading 14 volts.

[3300]

so there you have it! good to go for a few years again.
thanks for the update!

[Chris338378]

Yeah I'm in good shape now for a while and I'm going to put taking out the flasher and testing it to see how long the battery lasts on my pre-season check list.  I ended up getting a new battery locally and just my luck I saw today that the Sportsman's Guide has 12 volt 9 amp Universal batteries for $22 or $24 depending on if you're a member or not.  Oh well it was worth paying a little extra to have it working and without it I probably wouldn't have had as good a day fishing today as I did.  Thank you everyone for all your help, I greatly appreciate it.

[3300]

your very welcome! that's what we do here, give and take info.

amazon has good deals on them too. i do most of my shopping there any more. the 2 day delivery and free is hard to beat.

[Chris338378]

I didn't know they had second day delivery for free, I'll definitely be using that in the future.  Thanks again.

[3300]

with a prime account they do. i just guess every one has it.

[NateD]

your very welcome! that's what we do here, give and take info.

amazon has good deals on them too. i do most of my shopping there any more. the 2 day delivery and free is hard to beat.

Yep got mine for 15 bucks I think and haven't noticed a difference in quality.

I didn't know they had second day delivery for free, I'll definitely be using that in the future.  Thanks again.

Just sign up for the 30 day free trial and cancel it right away and they still let you use the 30 days.

[3300]

Yep got mine for 15 bucks I think and haven't noticed a difference in quality.

what do you mean no difference in quality? quality of the charge? quality of the build?

[NateD]

what do you mean no difference in quality? quality of the charge? quality of the build?

It works the same as any other battery I've had, only it is cheaper.

[3300]

ok cool, thanks!