Topic: Battery booster question.

[tomsweb1]

I recieved a battery booster for my birthday, which I am grateful for, but I don't have much use for if it can't charge batteries.
 I'm well versed in electrical theory, and can't think of any reason why it wouldn't, while it was plugged in.
 I know some of you guys out there know alot, about everything, it seems. So, I ask you, is there any reason why I can't?

 Thanks in advance!

[Duke McDukiedook]

Are you talking about a booster jumper type-deal?
I think those are only designed for small jolts to give cars a quick boost to start.
A battery charger usually does one thing; charges batteries.
Buy a battery charger if you want to charge batteries.

You'll learn to like that contraption a lot if you accidentally leave your lights on and the warning bell doesn't work on your car.

[my78k]

I too have one but found that over the years and little use it has depleted the internal battery. To be honest it never really had a ton of juice to boegin with. After I bought it I had buyers remorse but it was too late to take it back so instead I kept it and it works fine for jumping the bike and has a 12v outlet and a 120 switch so when the power goes out I plug a night light into it for the kids.

What I prefer now is my battery charger that has a 6v or 12 v settings and 3 amperage settings (2, 6 and 75 amp boost setting)

Dennis

[tomsweb1]

I do understand what it's for, and that a charger would be much better, but I have no money to buy one myself.

 My question is, will it charge batteries?

I think that it should... a 'dead' battery should draw off of the internal battery, and with the unit plugged in, it should maintain both batteries (connected in parallel, the interal charger would not differentiate between the two, merely see that the battery isn't 'full')

 Is there any reason why it wouldn't?

[TwoTired]

Is there any reason why it wouldn't?

Yes.  Charging batteries in parallel is fraught with issues.

Resistance of the interconnect leads means the battery nearest the charge source get fully charged when the far one doesn't.
Not all cells have the exact same charge potential at full charge either.  So, one battery or cell can be overcharged while another is overcharged.

You can charge one depleted battery from another charged one.  But, you cannot reliably maintain both batteries from one charger configured in parallel.
I'm sure some will claim they have done it.  And, it's IS possible, but not predictable.  If you have a digital volt meter and you frequently monitor the two batteries you can manually cycle the charging to maintain both batteries, adding human knowledge/intelligence to the task. 

[my78k]

TT, would connecting the bike battery to a high out put fully charged booster pack not also damage the bike battery?

Unless Tomsweb you only connected it once the internal battery is already flat. Admittedly my electrical knowledge is limited to say the least (or most I guess!).

Could you not discreetly take the booster back in return for a charger? I would suspect that the charger would be significantly less expensive.

Dennis

[TwoTired]

TT, would connecting the bike battery to a high out put fully charged booster pack not also damage the bike battery?

Current flows when there is a difference in potential.
If you parallel connect a fully charged battery to a fully charged battery and both are at 12.6v, no current flows between them regardless of size.
  When there is a potential difference between the two batteries, then current flows at a rate determined by the resistance of the connection and the internal resistance/impedance of the batteries.  Starting batteries have a very low impedance which enable them to provide large starting currents.  When new, these currents can be 200-600 amps initially (MC stating type batteries).  However, the transfer of energy depletes one battery (lowering its voltage) and raising the voltage of the other as it accepts charge, the current flow diminishes ever more so as the two batteries achieve the same voltage.  Without external influence, two interconnected batteries happily coexist in parallel connection.  With no other external connection, they will slowly self discharge until they both cease all chemical activity, and are incapable of creating a voltage w/current flow.

High currents create heat within the battery, either charging or discharging.  In dissimilar batteries, you can damage one or the other and this is related to the metal mass of each and it's ability to shed heat away from the heated elements.  I can only speak in generalities, because there is such a wide range of batteries in production from very small to very large, and the size dissimilarities matter.  So, talking about two 12V batteries is about the same as comparing two vehicles.  Each can either be the same as each other or very very different.

This help?

[Uncle Ernie]

A battery tender is around $30 and it will slowly charge a battery.
A new motorcycle battery takes from 4 to 6 hours. depending on size.

[tomsweb1]

Alright, I broke down and did it. I bought an automatic 2/6/12 amp charger yesterday, on sale, half price...

I love Canadian Tire!

Thanks again, guys! Your advice here is good as gold.

[Gordon]

2 amp is still pretty high for a small motorcycle battery.  Make sure you keep an eye on it when it's charging, and don't leave it on for too long or you can run it dry. 

[TwoTired]

Agree with Gordon.  2 amps is too high for constant battery maintenance, unless it is an automatic type that goes into maintenance mode when the battery is fully charged.   Then, it should work quite well.

[Uncle Ernie]

I used to use a charger before "tenders" were invented.  I plugged the charger into a timer so the battery would get a charge for about 20 minutes a day.  Seemed to work...
One of those things that turns your lights on for a while so burglers will think someone is home.

[tomsweb1]

Yup, it's an automatic one that tends your battery when it's full. Digital display that tells you how full it is, how many volts and amps it's giving it. It's a nice little unit.

[my78k]

I looked at that same unit the other day while I was killing time waiting for my van to complete the E-Test....it is a handy charger to say the least and for the price (I think it was around $45 right?) you can't beat it. If I didn't already have an OK charger and a tender I would have grabbed it!

Dennis

[tomsweb1]

That's the one! Motomaster Eliminator. On for 45 bucks, regular 89 something. A little christmas gift to me!

 Wait, you need to pass emissions tests in Ontario?
LAME.

[my78k]

On cars between 3 years old and I think 20. The bikes don't need em though... It is a total cash grab for the Gov't. Need to pass one every 2 years to keep your plates. 

Dennis

[tomsweb1]

Again, LAME.

It's strange I've neve heard of this before, though. I have many relatives in Kenora and Thunder Bay, and none of them have mentioned it. Wierd. and Lame.