Question about my battery tender and optima

[EScanlon]

I've charged a flat battery (under 7 volts) using my trick to fully charged green light in under 24 hours with my Battery Tender Junior.

And a pair of pliers will work instead of a wrench in some instances, but it isn't the BEST way to do things.

You're seriously over-working your little charger. I'll bet that the little transformer ends up being dangerously hot by the end, and even if it isn't HOT, you're pushing it way PAST it's design limits. Kind of a maximum weight limit on elevators, yes there is a safety factor, but past a given point.... I'll take the stairs.

Don't forget that in charging a battery, you're not just looking for a 12v read, you also have to consider it's capacity under load. I've had batteries that read 12v and could hardly get the starter solenoid to click let alone get the engine to turn over. Thats where cranking amps and reserve cranking amps come into play.

That's the reason for advising to use a PROPER battery CHARGER and not a TRICKLE charger.

We'll just keep our eye on the papers for the upcoming FIRE sale...

2¢

E

Edited July 25, 2010 by EScanlon

[Captain_Zeros]

The manual says you can use it to charge a battery, and what electrical knowledge I have tells me this is no big deal. It's not out of it's design specs to charge a battery, and as long as it's not pulling more than the .75 amps it's rated for it's not being overworked one bit (and considering it's a microcontroller based smart charger, it doesn't, it would go into an error shutdown mode if that occured.... which it hasn't). It doesn't get dangerously hot, and if a battery reads 13 volts it generally has the amps to crank a motor or anything else assuming the battery itself is damaged.

Read the battery tender website yourself, as long as the battery isn't COMPLETELY flat, charging it with the .75 amp charger is no big deal, it just takes forever, as much as two days. Do your research on a product first before going off on a tirade about how it'll burn my workshop down.

Edit: Here's the factory documents that describe how to charge a flat battery using a battery tender junior within spec.

http://batterytender.com/includes/languages/english/resources/Product_Instructions_BT_Junior.pdf?osCAdminsID=340cf056b7e37f3662e001e495eac704&osCAdminsID=340cf056b7e37f3662e001e495eac704&osCAdminsID=340cf056b7e37f3662e001e495eac704&osCAdminsID=340cf056b7e37f3662e001e495eac704

Edit:

The FAQ also says it's fine to charge similar batteries in parallel banks using the Battery Tender Plus which is basically the same brain + heat shutdown and an extra .5 amps of charging speed. It doesn't say whether it's okay or not to use the junior to charge banks, but I'm willing to take my chances while I supervise it for short periods of time.

Edited July 25, 2010 by Captain_Zeros

[sblake01]

You're missing the point. If you want to charge batteries with it, charge batteries with it. Your batteries, your vehicles, your workshop. E went a little beyond my feelings on the subject (which by the was is somewhat off topic) but I would prefer to use a charger to charge and a maintainer to maintain.

[sblake01]

I'm not sure what you mean when you use the term 'flat' which you described as 'under 7 volts', or the term 'COMPLETELY flat' but the BT instructions indicate that if the battery is under 3 volts that the safety circuit will prevent it from generating any output voltage. So you're bragging about bypassing the safety circuit in order to charge a dead ('flat' as you put it) battery?? I guess that's you're call.

Edited July 25, 2010 by sblake01

[Captain_Zeros]

No battery was EVER at three volts during the process, when I say "dead battery" I mean not enough power to fire up any of the car electrical not to mention crank the starter (headlights etc) which in my case was around 5-6 volts. My bypass trick involved using a "dead" battery at around 5 or 6 volts, and a fully charged battery between 12 and 13 volts hooked up in parallel to give a bank with an average of 8 volts or so which is perfectly fine to charge. (Interestingly enough I watched the Optima resurrection tip video posted earlier in the thread and they actively suggest doing the same exact thing). Throughout and beforehand I measured voltages and temperature of all the components of the system and supervised it fairly closer. The unit is a maintainer/charger, says so in the manual, anyways I've only used it on a dead-ish battery maybe two or three times, it stays hooked up as maintenance generally.

I'm comfortable with using it to charge, the documentation is fine with it and I only do it occasionally anyhow, it's not like I'm shorting it out and taking a vacation. It's had no issues so far nor has it displayed any behavior that would lead me to believe otherwise. I'm not saying other people have to charge with a Battery Tender brand battery charger, but I'm comfortable with it and telling me I'll burn down my garage by following the instructions.... feels a little extremist and like a personal attack.

[sblake01]

Fair enough, I was just trying to understand why it's so important to you to prove this point. I would have just moved on if it bothered me that much. Since it's the internet, however, there's no way it could have. You must be fairly young?

Edited July 25, 2010 by sblake01

[Captain_Zeros]

Whoops, rewrote that last message too many times, left out the part at the end that said "Lets stop arguing, it's dumb" in more words than that. I dunno, guess I'm youthful and naive (21), that and I like to clear up arguments that I believe are caused by misunderstandings in subject matter. (ie, I worked within specifications of a known brand of product, there has to be either something E knows that I don't and would like to learn, or I know something he doesn't and he ought to enjoy learning)

[EScanlon]

...I'm not saying other people have to charge with a Battery Tender brand battery charger, but I'm comfortable with it and telling me I'll burn down my garage by following the instructions.... feels a little extremist and like a personal attack.

It's not being an extremist, it's precautionary, if you feel it's a personal attack, then your paranoia is showing.

One of the things we look for in the threads on this site is to be sure that we don't advise people to check how much gas is in a gas tank using a match for light. You might get away with it, and you might not.... probably won't.

Your first post on this thread has this as one of it's key sentences:

...it's not designed for that kind of amperage (It'll blink the red light at you for 'error'), however I found a little trick to jerry rig it into trying....

Which, in plain english says, it's not designed to do something, but I found a trick in order to negate the safety /design features of the item and get it to do what it isn't designed to do.

Your second post affirms that you did it, and by implication, that it's perfectly safe to do... i.e. it's ok to bypass the design of the charger, after all you got away with it.

Putting batteries in parallel is a common trick to reduce the amount of current load placed on each battery when they're being used to power an item, but you're doing the inverse of that relationship.

You're starting the charge with a pair of batteries in parallel with a charger that is, admittedly, not designed to charge the one battery you are going to "fool" it into charging, because of the amperage it would require. I'll admit that it seems plausible, which is why you're getting the little IC chip inside the "brains" of the charger to buy off on it.

But, were you safe? Let's write the manufacturer and pose the same scenario to them and ask them if they would publish that as a "safe" work-around to charging a low voltage battery, as you are proposing here.

I'll bet they refuse to do so. Why? For the exact same reasons I cited in my cautionary post, and why once again, I'm posting this reply. It's not recommended nor is it safe.

You're welcome to presume any amount of knowledge you feel will justify your decisions, and you may find that you were right, or that you weren't. Sometimes you find out right away, other times it takes years, but you usually find out.

However, you might recall that our forum is known for being the correct place to get the correct information on the care of your Z. By your own admission, you "jerry-rigged" it into working. You claim to have "worked within specifications of a known brand of product", yet I could not find that same work around on their site BEFORE I posted the first time. So, taking proper precautions for this forum, I posted my views.

I did find this line in their Warranty Information document:

THIS LIMITED WARRANTY IS VOID under the following conditions:

1) The product is misused, subjected to careless handling, or operated under

conditions of extreme temperature, shock, or vibration beyond Deltran’s

recommendations for safe and effective use.

Like I said, let's pose the question to Battery Tender and see if they agree that it's safe and no problems. Then I'll retract what I posted, fair enough?

E

Edited July 26, 2010 by EScanlon

[Z train]

You're missing the point. If you want to charge batteries with it, charge batteries with it. Your batteries, your vehicles, your workshop. E went a little beyond my feelings on the subject (which by the was is somewhat off topic) but I would prefer to use a charger to charge and a maintainer to maintain.

Pure logic.

No Spock jokes ,please.

[OptimaJim]

Hello, I noticed your conversation regarding our batteries and wanted to offer some assistance. Zedyone kenobi, in your initial post, you mentioned that your previous alternator only put out 12.2 volts. Alternators should generally put out approximately 13.7-14.7 volts. I don’t know how long your battery was used in conjunction with that alternator, but it sounds like the battery may have begun to sulfate due to being in a partially-discharged state for an extended period of time. Sulfation will diminish both performance and lifespan, so maintaining voltage of at least 12.4 volts in a battery at all times can help minimize the impact of sulfation. That makes a battery tender or maintainer a great investment for any vehicle that is not driven daily.

If you charge your battery at a 10-amp rate for up to two hours, it can help break up this sulfation and restore some performance characteristics. Whenever you are charging a battery, whether it is done with the parallel charging technique discussed in this thread and described in our video or with a regular charger, if the battery gets hot to the touch or starts hissing or venting, you should discontinue charging immediately.

Fully-charged, RedTops should measure approximately 12.6-12.8 volts and YellowTops should measure 13.0-13.2 volts. A low amperage charge can charge a battery, but it will obviously take longer than a higher amperage charge. For example, take the rated capacity of the battery (for example, RedTop 34 is 50 amp hours or Ah). Think of the 50Ah as the size of your “fuel tank” for storing electrical power. You are using the charger to fill the fuel tank. If you have a 10 amp charger, this means it will put in 10 amps each hour. So for a 50Ah battery, charging at 10 amps, theoretically it will take (50 / 10 =) 5 hours for the battery to get fully charged. This assumes 100% efficiency in the charging process, that the charger will provide a constant 10 amps, etc.

In reality, most battery chargers to do not provide a constant current through the charging process – the current tapers off early in the charging process. If you own a battery charger that was purchased through typical consumer outlets (auto parts store, big box retailer, etc) this probably describes the charger you have. It may take 20-50% longer than the time calculated above with this type of charger. If you are going to purchase a new battery charger it is very beneficial to get one that is microprocessor controlled and has "AGM" compatibility. If it has a separate setting for AGM batteries it will enhance the battery’s performance and potentially extend the life. There are some common consumer battery chargers that have “Gel” or a confusing “Gel/AGM” setting. Do not use this setting as this will not fully charge an Optima and will damage it over time.

If anyone has any questions about our batteries, I’ll do my best to answer them. I appreciate your interest in our batteries!

Jim McIlvaine

eCare Manager, OPTIMA Batteries, Inc.

www.facebook.com/optimabatteries

[Unkle]

So to further the poking .....

Optimajim , can you say that the above people / person using the bypass

trick and ''charging'' batteries this way with a .75 amp unit is a good / proper

way of doing business , or are you simply an Optima salesman seeing an

opportunity to '' slightly advise , advertise , and leave " ?

Here's a chance to help a 21 year old ( and all of us ) make safe practices !

[Zedyone_kenobi]

I want to thank OptimaJim for taking the time to respond with very accurate information. My optima will only get to 12.4 v, which is pretty close to the red top specifications listed by Mr. Optima above. I will keep up with my battery tender jr, and keep my redtop healthy for as long as I can. I have had great luck with my optima. For the record, even at 11.2 volts my optima was able to crank my datsun. It is a great product.

I know this thread got off topic a tad, but thanks to optimajim for helping out. It is good to see a vendor go the extra mile to give some personalized information. Thanks Jim.

I will try to run my dedicated battery charger at 10Amps for 2 hours to try to break up the sulfates.

Have a great day.