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graydude
Dec 5th, 2005, 1:10 pm
I have the gel battery and a battery charger that has 75 amps for starting, 10 amps for charging and a 2 amp automatic maintenance mode. Can anyone think of a reason why I can't use the 2 amp mode for trickle charging or do I have to get one of them fancy little charges?

JPSpen
Dec 5th, 2005, 1:52 pm
I'd get a battery tender for gel battery's...The one you've got is probably for Acid (wet) battery's and not gel...

Even a 2-amp will eventually overcharge the battery and possibly burn it up...

The Battery Tender has a true "float" charge that won't damage the battery..

Good luck.
Spence

KYLT05
Dec 5th, 2005, 2:06 pm
I have a Battery Tender Plus for Gel Batteries. Looks just like the standard Battery Tender but is programmed for gel batteries. Has a sticker on the top of the unit that says "Programmed for Gel Batteries" About $25 cheaper than the BMW charger.

GSinNC
Dec 5th, 2005, 5:46 pm
I have a Battery Tender Plus for Gel Batteries. Looks just like the standard Battery Tender but is programmed for gel batteries. Has a sticker on the top of the unit that says "Programmed for Gel Batteries" About $25 cheaper than the BMW charger.

OK ... here is my question which I do not think has been answered. If I can put a Gel battery into a bike that was designed for a lead acid battery and it will work fine with the charging system on the bike. Why can I not use a battery Tender designed for a Lead Acid battery on a Gel Battery. I may not be technical enough but it just does not sound logical. Almost sounds like the gel battery will not be able to tell the difference in bike charging systems but the gel battery can tell the difference in Tenders? What am I missing?

I am also told that my BMW dealer can not get a Lead Acid battery to replace the one in my '02 R1150GS and the will only be able to replace with a Gel. Is that true? My battery is 3+ years old and I would probably replace next year. It has served me well and NEVER any issues and virtually never needs water added.

dgoodbmw
Dec 5th, 2005, 6:36 pm
ed, your dealer is right, BMW no longer provides a replacement acid battery for your machine. any of the newer machines will have to use gel. there may still be aftermarket avail, but not from BMWNA. don

BecketMa
Dec 5th, 2005, 6:46 pm
You can use the battery tender (for “normal” batteries) with the sealed battery. However the battery tender is not designed for maximum performance into the sealed battery. While both types of batteries are batteries, the internal resistance, capacitance, and voltage for the individual plates are not identical.

Normal batteries are shipped empty. The acid has to be added. The battery should be fully charged after the acid is installed.

Because of the labour savings, BMW switched to the sealed batteries, according to my local dealer. BMW can ship a new bike with the battery installed.

I ordered my sealed batteries over the internet. I found the last one I ordered, laying on its side, in my drive way, next to my car. The UPS driver didn’t want to walk to my front door. Imagine what would happen if we ordered normal batteries! Ship acid via UPS? NO WAY! Besides, not legal.

Bob

Russ
Dec 5th, 2005, 6:52 pm
"OK ... here is my question which I do not think has been answered. If I can put a Gel battery into a bike that was designed for a lead acid battery and it will work fine with the charging system on the bike. Why can I not use a battery Tender designed for a Lead Acid battery on a Gel Battery. I may not be technical enough but it just does not sound logical........."

I (and others) asked this same question in more then one thread over at BMWST.com and never received THE answer (that I can recall). Anyone want to venture an answer from this forum?????

regards

GSinNC
Dec 5th, 2005, 8:05 pm
You can use the battery tender (for “normal” batteries) with the sealed battery. However the battery tender is not designed for maximum performance into the sealed battery. While both types of batteries are batteries, the internal resistance, capacitance, and voltage for the individual plates are not identical.

Normal batteries are shipped empty. The acid has to be added. The battery should be fully charged after the acid is installed.

Because of the labour savings, BMW switched to the sealed batteries, according to my local dealer. BMW can ship a new bike with the battery installed.

I ordered my sealed batteries over the internet. I found the last one I ordered, laying on its side, in my drive way, next to my car. The UPS driver didn’t want to walk to my front door. Imagine what would happen if we ordered normal batteries! Ship acid via UPS? NO WAY! Besides, not legal.

Bob

Not sure how it got here but I order a Lead Acid Battery for my Valkyrie from Honda Direct Line and it shipped .... I think UPS ... Acid and all. The acid came in a sealed container and the instructions were pretty simple. Worked fine!

GSinNC
Dec 5th, 2005, 8:06 pm
"OK ... here is my question which I do not think has been answered. If I can put a Gel battery into a bike that was designed for a lead acid battery and it will work fine with the charging system on the bike. Why can I not use a battery Tender designed for a Lead Acid battery on a Gel Battery. I may not be technical enough but it just does not sound logical........."

I (and others) asked this same question in more then one thread over at BMWST.com and never received THE answer (that I can recall). Anyone want to venture an answer from this forum?????

regards

I agree with you Russ! Something is missing .

Zotter
Dec 5th, 2005, 11:43 pm
Personal opinion here, I'm not a charger tech and don't even play one on teh Internet - very often. But I don't know that there's anything much different to the output of a 'gel charger' from a 'flooded charger'.

What's different is, a gel charger will 'sense' the current state of charge on the battery - like your bike's charging system does - and roll back the voltage. The curve of roll back may well be part of the difference between a flooded cell 'smart' charger and a gel charger.

A fixed, lead acid charger won't roll back it's voltage - no matter what the battery's charge status, it'll output whatever you have it set at. Leading to the likelyhood of 'cooking' off the battery's electrolyte.

Here - see what I did to a flooded, lead acid battery with a motorcycle 1 amp charger - that wouldn't have happened with either the bike's charging system or a 'gel' charger. Both would've detected the charged state of the batery and folded back the input voltage to maintain - not charge further.

http://www.bmwlt.com/forums/showthread.php?t=2602

Hey, it's a SWAG - any battery engineers out there to verify or refute?

tvguy
Dec 6th, 2005, 2:08 am
Hi Graydude,

You have a car charger. DON't use it. 1 amp is the max for a motorcycle battery. Buy a "Battery Tender" or the BMW unit and you won't have a problem. I have the BMW unit and it plugs into the outlet by my left foot

BTW - are you going to the Long Beach bike show this weekend?

tvguy

messenger13
Dec 6th, 2005, 2:40 am
You have a car charger. DON't use it. 1 amp is the max for a motorcycle battery. Buy a "Battery Tender" or the BMW unit and you won't have a problem.If 1 amp is the max for a motorcycle battery, then how come the BT Plus (and the BMW unit) is rated at 1.25 amps (http://batterytender.com/product_info.php?products_id=2&osCsid=21ea48428ab1d943f52dae1236922bb0)? The 'Junior' is rated at 0.75, IIRC.


Graydude, If you ask me...I'd tell you to go ahead and use that 2 amp charger (for now)...but ONLY if it has the over-charge protection circuit built into it. Save your pennies, and when you have 40 extra bucks laying around, order a BT Plus online. You'll need to buy the BMW to SAE adapter too. That's another $10 that most people leave outta the equation.

HTH

GSinNC
Dec 6th, 2005, 4:59 am
Personal opinion here, I'm not a charger tech and don't even play one on teh Internet - very often. But I don't know that there's anything much different to the output of a 'gel charger' from a 'flooded charger'.

What's different is, a gel charger will 'sense' the current state of charge on the battery - like your bike's charging system does - and roll back the voltage. The curve of roll back may well be part of the difference between a flooded cell 'smart' charger and a gel charger.

A fixed, lead acid charger won't roll back it's voltage - no matter what the battery's charge status, it'll output whatever you have it set at. Leading to the likelyhood of 'cooking' off the battery's electrolyte.

Here - see what I did to a flooded, lead acid battery with a motorcycle 1 amp charger - that wouldn't have happened with either the bike's charging system or a 'gel' charger. Both would've detected the charged state of the batery and folded back the input voltage to maintain - not charge further.

http://www.bmwlt.com/forums/showthread.php?t=2602

Hey, it's a SWAG - any battery engineers out there to verify or refute?

Again .... I do not disagree with anything you stated BUT I believe you are talking about "chargers" and not "tenders" which stop charging when the battery reaches full or near full charge.

But the simple question has still not been answered ..... how does a bike built for LEAD ACID battery and charging system not harm the GEL battery but the same Tender built for a LED ACID battery hurt the GEL battery?

Hey trust me I have 2 Tenders now but if I got a GEL I would get a BMW Gel Tender JUT TO BE SAFE and not risk any issues if the battery does go bad ..... But it just seems like we are being asked to buy something we do not need.

Big_E
Dec 6th, 2005, 12:50 pm
Just ordered 3 of these, they also have the plug for the BMW power outlet. http://www.motorcyclebatteriesusa.com/battery-chargers-details.asp?battery=91

Russ
Dec 6th, 2005, 1:02 pm
(Just to keep this thread alive until a "battery engineer" chimes in....)

What was discussed on another forum was not that the battery tender charging programs/ratings (bulk/absorbtion/float modes) were altered, but it was the new charging "algorithm" that Deltran claimed was different for gel batteries. To which some of us then asked why would a gel battery be okay to use in a motorcycle with the "old" charging algorithm but not with a BT that had the "old" charging algorithm?????

regards

JeffB
Dec 6th, 2005, 1:32 pm
I had the same questions posed by many here about the difference between the motorcycle's charging system and a battery charger. My personal opinion was/is that if the motorcycle's charging system is not that particular, why does a separate charger need to be.

I had some conversations with Deltran about this previously. I see if I can find additional info when I'm home. A couple points I do remember: First is that Exide required a particular charging algorithm for their batteries and BMW contracted Deltran to supply chargers that met the Exide requirements and IIRC it only involved the first phase of charging. The second had to do with the answer to the question "have you ever had a report of a BMW gel battery be harmed by the standard Battery Tender Plus?" Their answer was "no". They were very cautious with the discussion we had via email and offered to talk to me via phone. I never called them after I got the answer to the question above. If someone is interested in having this discussion with them I will try to find the contact info for the person that made the offer, I don't believe he was the customer support person that was answering my other emails.

In answer to the original post, do not use a high amperage charger for the small battery in a motorcycle. This is particularly important if you plan on leaving it connected to maintain the battery over time. In this case the charger must go into "float" mode or the battery will eventually fry.

jwd98056
Dec 6th, 2005, 2:50 pm
Maximum Charge Rate

The maximum rate of charge for a lead acid battery is usually specified as 20% of the battery capacity. So depending on the brand of battery you are looking at the capacity for the LT battery is somewhere between 16 and 20 Amp hours. That put the maximum charge rate at something like 3.2 to 4.0 Amps.

Chargers

Most smart chargers rely on voltage to determine when to switch from one charging mode to another. Here is a description from the Yausa Battery web site that gives a good description of the process:
----------------------------------------------------------------
"Within the past several years, several companies have developed chargers that can charge a depleted battery quickly, and then hold the battery at a voltage that will neither cause it to gas nor allow it to self-discharge. These are sometimes referred to as “smart chargers” or multi-stage chargers. Here’s how they work.

We said that a battery could accept a much higher rate of charge when it’s partially depleted than when it’s near full charge. These multi-stage chargers take advantage of that fact by beginning the charge in a constant current, or “bulk charge” mode. Typically, they provide a charge rate of between 650 milliamps and 1.5 amps, depending on make and model. This bulk charge is held constant (or should be) till the battery voltage reaches 13.5 volts, thus allowing the battery to absorb a larger amount of charge in a short time and without damage. The charger then switches to a constant voltage or “absorption” charge. The idea here is to allow the battery to absorb the final 15 percent of its charge at its natural absorption rate to prevent undue gassing or heating. Finally, these chargers switch to a “float” mode in which the battery voltage is held at a level sufficient to keep it from discharging but insufficient to cause overcharging. The various companies disagree generally on what this float voltage should be, but it’s usually between 13.2 and 13.4 volts. Actually, the float voltage should be temperature compensated between 13.1 volts at 90 degrees Fahrenheit to 13.9 volts at 50 degrees. Most of the very expensive high power multi-stage chargers for use on larger RV batteries are temperature compensated, but none of the motorcycle units are to my knowledge; they use a compromise float setting."
-----------------------------------------------------------


The primary difference with the programming for different battery types is usually in the second stage of the charge or the absorbsion rate charge cycle. That is for charging the last 15-20% of the battery capacity. Different battery chemistries have different absorbsion rates and that cycle may need to be different to get the full 100%. It is also possible that the voltage decision points may be slight different.

This brings some issues to mind:

1) Why is it important to keep a lead acid battery fully charged? To keep the formation of lead sulphate to a minimum. The creation of lead sulphate increases dramatically if the battery is kept at 90% of capacity or less. Lead sulphate is the main cause of battery failure over time.

2) Another big cause of failure can occur when a motorcycle battery is discharged more than 15% of it's rated capacity. The lead plates in the battery can be deformed. Every time this happens another nail goes into the battery's coffin. Depending on the battery design a single full discharge can potentially result in significant damage. This can affect the capacity and the voltage of the battery.

3) What impact does using a charger "programmed" for one automotive battery type on a different battery type? It means either the battery won't be charged to 100% of capacity or there is a potential for a slight over charging condition.

As long as the battery is above 90% capacity the first condition probably doesn't matter much. Seeing as how these batteries are all designed to operate in the same environment, i.e. 12V automotive systems, their design specifications can't be drastically different. Though I don't have any specific information to support it, I doubt there would be significant detrimental effects to the slight overcharging.

Automotive electrical systems have variations such as voltage regulator tolerances, wiring/connector resistances, battery tolerances, etc. that could subject batteries to similar over/under charging conditions during operation. I don't think one or two percent of charge capacity amounts to a fart in a wind storm. Just my $0.02.

BMWphreak
Dec 6th, 2005, 3:04 pm
When you drive your K1200LT, the charging system is putting out approximately 14.2 volts. I know many of us have run their bikes at least 8 hours a day for several days in a row, and I don't think anyone is concerned that they will fry their battery from too much riding. If you really are concerned that your non gel cell battery charger is going to fry the battery if left on continuously, add a cheap timer to only charge the battery a few hours a day. My $17 Walmart battery "tender" puts out a maximum voltage of 13.2v, so I don't see an issue, but I am not about to tell anyone to use one of these if they don't feel comfortable with it any more then I'd tell them which oil they should use!

The best solution may be to simply become a 'rounder.....

Russ
Dec 6th, 2005, 8:32 pm
'I had some conversations with Deltran about this previously. I see if I can find additional info when I'm home. A couple points I do remember: First is that Exide required a particular charging algorithm for their batteries and BMW contracted Deltran to supply chargers that met the Exide requirements and IIRC it only involved the first phase of charging.'

So.............

Exide informs BMW their gel battery requires a particular charging algorithm.

BMW contacts Deltran to supply chargers that met that requirement.

BMW does not alter/retrofit the charging systems of their bikes to meet that requirement.

Have I got it right? (Yea, I know I'm "this close" to beating a dead horse.)

regards

JeffB
Dec 6th, 2005, 9:09 pm
Let's bury the horse. The following is a summary of my communications with Deltran. After reading the second quote you will see why they are cautious in what they say.

When inquiring about the difference between the gel and standard chargers I received this response:
There is a difference; the Battery Tender Plus is our most versatile model.
Here is the "official response" that I received from Deltran and was also posted on the old site by someone else (notice the careful wording and the BMW warrenty comment):
BMW sure did create a quandary for their customers (and us) with the gel type battery. The following is a message from the company president.

I will try to end the confusion about the new BMW Gel battery Battery Tender.

The BMW Gel Battery Tender is in fact different than the normal Battery Tender Plus. Although the Deltran Battery Tender Plus and the BMW Battery Tender appear the same they are quite different. Approximately one year ago BMW contacted us concerning their new Gel battery that is manufactured by Exide battery in Germany. We were instructed to redesign the charge algorithm to comply specifically with the new Exide Gel battery. Exide recommended very specific changes to the charge curve, one being a timed sequence during the absorption period. Please keep in mind that our engineering staff has been designing charge curves for over fourteen years and prior to this design request had never seen anything quite like the new Exide Gel.

As the old saying goes, "the customer always knows best," we can only do as requested. If BWM/Exide says charge it to their instructions and the battery will last through the warranty period who are we to argue. If it is any consolation, we have found it to be a very good battery and should give you many years of service.

We do claim per our packaging that we correctly charge gel batteries, prior to seeing the Exide battery that statement was true, we are now changing our packaging to indicate otherwise. Due to the new battery design, and to comply with the BMW warranty, the customer must purchase a "Gel Specific" battery charger.

After all these years in the charger business we are still amazed how every manufacture try's to re-invent the battery. We realize that with all the different batteries in the market place the customer becomes very confused and is usually forced to spend more money. Approximately three years ago Harley-Davidson changed their battery design and manufacturer, it proved to be a very wise decision and we can only hope it works out best for BMW, and most importantly, you the customer.

Sorry for the Confusion,
Mike Prelec
President,
Deltran Corp.
And from my question on reported problems with using it with a BMW gel:
There have been no reported problems or ill effects on the gel battery from the regular Plus. I have used it to charge bmw gel and seemed to work ok. I don't know about long term use though.
Finally I will reiterate what I said in a post on another thread. Since the cost of the gel specific charger is about the same as a new battery, it makes more sense to buy a more universal charger and if the battery dies a little early just replace it with a non-BMW gel or AGM battery and keep using the same charger instead of buying a specific charger that isn't appropriate for use with AGM or a standard wet cell. It's cheaper in the long run.

I think Russ summed it up pretty well in the previous post.

dsidler
Dec 6th, 2005, 9:57 pm
I still don't think the original question has been answered. We're talking "Battery Tenders" here, both the old kind and the so-called new kind designed to tend the new gel batteries. "Or designed to make more profits for the company that makes the battery tenders." His question is... if a gel battery can replace a lead/acid battery without changing the charging system on the vehicle, why is it that an original battery tender cannot be used with the new gel battery, as well as with a lead/acid or sealed battery. I'm still waiting for a "logical" explanation.

JeffB
Dec 6th, 2005, 10:00 pm
I personally don't think you will find a "logical" answer.

Zotter
Dec 6th, 2005, 10:23 pm
Again .... I do not disagree with anything you stated BUT I believe you are talking about "chargers" and not "tenders" which stop charging when the battery reaches full or near full charge.

But the simple question has still not been answered ..... how does a bike built for LEAD ACID battery and charging system not harm the GEL battery but the same Tender built for a LED ACID battery hurt the GEL battery?

Hey trust me I have 2 Tenders now but if I got a GEL I would get a BMW Gel Tender JUT TO BE SAFE and not risk any issues if the battery does go bad ..... But it just seems like we are being asked to buy something we do not need.


As to the "Tender" and "Charger" question - I was mostly mixing the two:

Any vehicle's charging system is a "Charger" if the battery is depleted. But, if there's a full or near full charge on the battery that same "Charger" becomes a "Tender". It's all to do with that 'sensing the battery's current state of charge' and rolling back the charging voltage routine.

The 'new' charger I got for my Odyssey is a "1.5A" charger - but, it's specificly stated in the documentation (and verified with the "Battery Tech" at the shop) that I can leave it connected to my Odyssey for as long as I want with no ill effect. At that point - it becomes a "Tender", same as the system on the vehicle. As it drops output voltage and internal resistance in the battery increases (due to increased charge level) - the drawn current (amperage) is going to be much lower than the 1.5A available.

Now, what may well be different - and what I think is 'different' between a lead acid and a 'gel' device - and is at least alluded to by the quotes offered from Deltran - is the 'curve' of what the voltage levels are cut back to as certain battery voltages are sensed or times at certain output. I'm guessing that 'curve' is the diff between a 'normal' whatever and a 'gel' whatever - be it a 'charger', vehicle system or a 'tender'.

Like many things in electronics, I think you could measure the differnce, but in practice and application - it ain't likely to affect performance or even be noticed in use.

Seems we may be buying into the 'Marketing' speak - missing the obvious in the pursuit of definition.

GSinNC
Dec 7th, 2005, 4:23 am
As to the "Tender" and "Charger" question - I was mostly mixing the two:

Any vehicle's charging system is a "Charger" if the battery is depleted. But, if there's a full or near full charge on the battery that same "Charger" becomes a "Tender". It's all to do with that 'sensing the battery's current state of charge' and rolling back the charging voltage routine.

The 'new' charger I got for my Odyssey is a "1.5A" charger - but, it's specificly stated in the documentation (and verified with the "Battery Tech" at the shop) that I can leave it connected to my Odyssey for as long as I want with no ill effect. At that point - it becomes a "Tender", same as the system on the vehicle. As it drops output voltage and internal resistance in the battery increases (due to increased charge level) - the drawn current (amperage) is going to be much lower than the 1.5A available.

Now, what may well be different - and what I think is 'different' between a lead acid and a 'gel' device - and is at least alluded to by the quotes offered from Deltran - is the 'curve' of what the voltage levels are cut back to as certain battery voltages are sensed or times at certain output. I'm guessing that 'curve' is the diff between a 'normal' whatever and a 'gel' whatever - be it a 'charger', vehicle system or a 'tender'.

Like many things in electronics, I think you could measure the differnce, but in practice and application - it ain't likely to affect performance or even be noticed in use.

Seems we may be buying into the 'Marketing' speak - missing the obvious in the pursuit of definition.

OK ... I am with you all the way on this. And I agree with your statements and I even understand what "may be" the issues with a gel whatever and lead acid whatever ..... but if that "curve" is different in the tenders ... why is it NOT different in the bikes. The bikes charging curve was built to charge the lead acid battery as was the normal tender .... if the normal tender has a curve that will harm the gel ... why does the bike's charging system not harm the gel battery?

You have stated your case very clearly! Thanks!

Dezrae
Dec 7th, 2005, 5:19 am
Just for interest, i use a "Arlec Charger 6".Infact i have 2 of them.
Have done so for the last 5 years. First used it on my VFR800. got 3 years out of my 1st battery and the 2nd battery was still in it when i sold the bike 2 years after i replaced the 1st battery.
When my garage had the VFR800 and the K1200RS they both had their own chargers.When my Dad had the K1200RS he also had a Arlec Charger 6 wired to the battery via one of the bmw power sockets.

I bought mine from Repco, but im sure that Dick Smith, Jaycar,Kmart and the likes would sell it as well
When i bought mine they were just $60 each.
I just did a quick look on google and i see prices vary from $70 to $160 now!!!

bushj1
Dec 7th, 2005, 9:32 am
Finally I will reiterate what I said in a post on another thread. Since the cost of the gel specific charger is about the same as a new battery, it makes more sense to buy a more universal charger and if the battery dies a little early just replace it with a non-BMW gel or AGM battery and keep using the same charger instead of buying a specific charger that isn't appropriate for use with AGM or a standard wet cell. It's cheaper in the long run.

. [/size][/size][/size]

I bought a BMW Gel August of '03 and used an Optimate 3 charger. I kept the charger on the battery, not the socket, whenever bike was in garage. In that time I put over 50,000 miles on the bike, so you can see it was not in the garage a lot, but never-the-less was hooked up when in the garage. This past October, the bike failed to start in the parking lot at grocery store. The battery had been showing signs of weakness for the prior 2 months.

I am assuming the Optimate was not charging high enough at the onset of hook up to meet the BMW criteria for the battery as explained in previous post quoted from the DelTran people. I replaced with another BMW gel battery and have noticed that it takes 1 to 2 hours for the optimate to bring the battery to full charge after having been out for a ride. I may have already ruined the new battery, but am going to have it tested this month when in for other issues. I'll have the alternator out put checked first, then decide if I need the "special" BMW charger.

It appears on the surface the Optimate is not an option over time at least for the BMW battery.

Russ
Dec 7th, 2005, 10:36 am
"I am assuming the Optimate was not charging high enough at the onset of hook up to meet the BMW criteria for the battery as explained in previous post quoted from the DelTran people. I replaced with another BMW gel battery and have noticed that it takes 1 to 2 hours for the optimate to bring the battery to full charge after having been out for a ride. I may have already ruined the new battery,......"

Since our bikes do not have the different charging algorithm or "curve" that the new gel batteries require, why can't I ASSUME that our bike's charging system is "ruining" these gel batteries every time we ride?????

regards

Zotter
Dec 7th, 2005, 6:29 pm
OK ... I am with you all the way on this. And I agree with your statements and I even understand what "may be" the issues with a gel whatever and lead acid whatever ..... but if that "curve" is different in the tenders ... why is it NOT different in the bikes. The bikes charging curve was built to charge the lead acid battery as was the normal tender .... if the normal tender has a curve that will harm the gel ... why does the bike's charging system not harm the gel battery?

You have stated your case very clearly! Thanks!

Thanks! My English teach might finally be impressed :o

Ya know? I'm not sure what the diffs might be. But I'd wager the 'difference' is more along the ideas of what an 'ideal' curve is rather than one or the other actually doing 'harm' to anything. Hence my comment about the 'marketing' speak.

Gotta admit, I've not yet seen anyone say DON'T USE a tender/smart charger on a gel type battery. Mostly just seen folks trying to sell something that many of us already have - with a different label on it. But then I'm told I'm a synical ol fart - haven't seen much evidence of that either. :D :D

Seeker
Dec 10th, 2005, 11:13 pm
I have the gel battery and a battery charger that has 75 amps for starting, 10 amps for charging and a 2 amp automatic maintenance mode. Can anyone think of a reason why I can't use the 2 amp mode for trickle charging or do I have to get one of them fancy little charges?

That's what I use. I have an AGM battery that was put in service in summer 01. I set the automatic charger at 2amp setting. Automatic means that it will adjust output as battery charges. A manual charger at 2amp or even a manual trickle charger of 1 amp will eventually cook a battery if left on after battery is fully charged.

The operative word is automatic or fully automatic.

Some batteries, like the Odyssey, require a higher initial voltage ie 14,7 volts IIRC, in order to fully charge the battery. If your charger or 'Tender puts out a lower voltage ie 14,2 volts, it may not fully charge the battery. My automotive charger has a setting of 2/10amp along with a setting of 75 amp for starting. Charging is fully automatic. It has no problem putting out that initial higher voltage. In fact, it even has a setting where it can put out even more voltage in order to de-sulphate battery plates.

Just make sure that you have the charger set on automatic. If you have a voltmetre, you can take a reading while it is charging.


Bruno
Montreal, Canada
Gerbing Heated PANT LINER Review
http://pages.videotron.com/mcrides/product_evals/gerbing/p-liner.htm
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