View Full Version : How to charge battery without battery charger?


bmwpower
03-10-2007, 04:16 PM
I don't have a battery charger. I need to charge a battery for a car, but I don't want to stick it in the car and jump the car with another since the battery is dead.

Can I hook the battery inline with another battery in another car and charge it?

ThrashN
03-10-2007, 04:34 PM
I'm not sure if that would work or not. I'm thinking you'll just kill the battery with the charge. I know you said you didn't want to buy a charger but I picked up a small trickle charger from walmart for $20 that does a great job.

MAD
03-10-2007, 04:57 PM
If the dead battery is just dead and not bad, you should be able to charge it with the other vehicle by starting the good car and then connecting the dead battery in parallel with jumper cables as you would if you were jumping it. Then allow the car to run until charged. This may take a while (25-30 min?) because you are charging both batteries. You will probably want to block the throttle open a little so the car runs at 1500-1800 rpm. I don't think you will get enough of a charge if you try it without running the car to help charge the battery. I don't think you need me to tell you that you should get a charger.

bmwpower
03-10-2007, 06:35 PM
Yea, I know, I know. It's on my list of things to get. I guess I should just go out and get one.

ranger_dood
03-10-2007, 06:41 PM
Take any 12v wall wart power adaptor you might have laying around, cut the tail off, and you're golden! Let it sit overnight at it should keep enough charge to start a vehicle. It depends on the amperage output of the wall wart, though.

SuperKid
03-10-2007, 07:27 PM
Yea, I know, I know. It's on my list of things to get. I guess I should just go out and get one.

Yeah, seriously. With that nice garage of yours it would be silly to be doing shade-tree mechanic stuff like that. Head to Sears and get a DieHard automatic battery charger for less than $100.

ImportTuner
03-10-2007, 07:53 PM
Yea, I know, I know. It's on my list of things to get. I guess I should just go out and get one.
Yeah, just pick up a battery charger; alot safer than what you had in mind ..

Deafautotech
03-10-2007, 09:50 PM
i have my Harley davidson sportster on automatic battery charger and i paid it for 40 dollars at harley store that fit my and all vehicles if need to charging all winter season. so i did keep my harley's battery charging and it is working great because i just started it up and it is fire right after start. i am glad to have it charging battery while winter season....

cc_rider
03-12-2007, 12:33 PM
A 'wall wart' is not likely to have enough oomph to charge a car battery. I've never tried it, but most are under an amp; they don't carry much juice. I might try it sometime though...

c.

Stuart in MN
03-12-2007, 12:55 PM
I think a wall wart would do the job, the only thing is it'll keep charging as long as it's plugged in so you'll have to pay attention to it.

I have an ancient trickle charger that runs at about 1/2 amp, so it's about the same thing and it works fine - it just takes longer than a regular battery charger and it doesn't shut itself down once the battery is charged.

ranger_dood
03-12-2007, 06:07 PM
My brother runs a wall-wart on his supra. It has an untraceable drain that kills the battery after about a week. Since it's not always a daily driver, he just ran an extension out to under the hood and hooked the adapter up out there. Works great, I just would have to hope that it never decides to melt down.

Also, it makes the Supra look like a diesel with the cord running under the hood.... except it's like that all summer, too :D

HOTFR8
03-12-2007, 06:11 PM
Every thing of mine with a battery either has a C-Tek or Deltrans tender.

Rarely do I have battery problems.

ranger_dood
03-12-2007, 06:11 PM
Also, I have an interesting story relating to this issue. Just last weekend, we went to start my dad's truck which had been sitting for a week or so. Well, the last time we ran it, the alternator wasn't keeping up the charge, so we put a new alt on it. Only, we didn't run it after that. So, the battery was just a little too dead for a stone-cold engine... The truck was parked towards our barn door, and was surrounded by a sheet of ice, which is why we wanted to move it.

So, battery's dead... okay, we'll pull it and charge it off another battery. Let it sit for about 5 mins, took it back to the truck... no go, still not enough. So, we decide to jump it with the lawn tractor that's parked in the barn. Jump on the tractor, and all we get is about half an "uhh" out of it. So I get the bright idea... well, the battery in the truck isn't enough to turn over the large 8 cylinder, but it should be enough to start the tractor... So, we push the tractor over, jump it off the truck battery, let it run, while hooked up to the truck, for about another 5 mins at full throttle, and ended up with enough charge to start the truck. Talk about robbing Peter to pay... well... Peter.

JohnZ
03-14-2007, 06:06 PM
Buy a battery charger - they're not that expensive. If you rig up the dead battery with jumper cables as posted earlier, it might cost you a new alternator; alternators aren't designed to charge dead batteries - they're designed to maintain them. I've used a Deltran "Battery Tender" for many years on my seldom-driven cars when they're in storage over the 6-month winter - I connect them about once a month, takes 12-18 hours to bring them up to a full charge. This keeps them healthy - I routinely get 8-10 years out of a battery, haven't bought one for years.

:beer:

bmwpower
03-15-2007, 01:29 PM
This Sears one look good? I've used my friend's manual charger...no fun, but this one looks like it would do the trick...

http://www.sears.com/sr/javasr/product.do?pid=02871225000&vertical=TOOL&BV_UseBVCookie=Yes

ImportTuner
03-15-2007, 02:11 PM
Here's the one I have; also from Sears; paid $79 on sale - sale happens every 2~3 month ... 200 amp jump charge ...

Down Under Bloke
03-15-2007, 07:30 PM
The Big 200amp jump/charge is good for professional shops where you want to get things going NOW and also for cheap car yards, but for home and if you aren't in a panic 30amp should be heaps.

Having said that 200 amps for $79, dam that's good, you would just want to be comfortable with the amount of real estate it will occupy.

HOTFR8
03-15-2007, 07:39 PM
I routinely get 8-10 years out of a battery, haven't bought one for years.



Yes I have found the same. Average life of a conventional car battery is two years. The C-Teks and Deltrans Chargers are by far the best thing I have ever owned. The C-Tek is a better unit, being fully sealed makes them weather proof as well.

thefairlaneman
03-15-2007, 10:32 PM
You want a quick no cost way to charge that battery? OK Heres an "old school" way to do it without spending a dime. Take your other car and crank it up. While running you remove the battery ,and dont let the connections touch anything. Then you pop in your dead battery and hook it up to the correct battery post. DONT CUT THE CAR OFF,because it is now charging the battery. let it run for approx 10 minutes and then cut the engine off and see if it will restart the car. If so your battery is now charged.

TNToy
03-15-2007, 10:41 PM
You want a quick no cost way to charge that battery? OK Heres an "old school" way to do it without spending a dime. Take your other car and it up. While running you remove the battery ,and dont let the connections touch anything. Then you pop in your battery and hook it up to the correct battery post. DONT CUT THE CAR OFF,because it is now charging the battery. let it run for approx 10 minutes and then cut the engine off and see if it will restart the car. If so your battery is now charged.

I wouldn't even THINK about trying that in anything with EFI. Carbs tend to ignore power surges... but ECMs are expensive.

;)

TNToy
03-15-2007, 10:45 PM
My brother runs a wall-wart on his supra. It has an untraceable drain that kills the battery after about a week. Since it's not always a daily driver, he just ran an extension out to under the hood and hooked the adapter up out there. Works great, I just would have to hope that it never decides to melt down.
Toyotas have a weird tendency: Corroded battery cables cause a current drain. My pickup would run down a red-top optima in 3 days if left sitting, and wouldn't start afterwards. If run daily, it was fine.

I finally got around to hooking my Fluke up to measure the current draw on the battery when idle, and did the ususal fault-tracing... pull fuses 1 by 1 to see if the draw goes away, etc. Nothing worked. I finally decided to start measuring resistance in various places. Well, both the ground and positive battery cables had REALLY high resistances... slit the insulation and there was severe corrosion on about 6 inches of both cables, hidden from view.

Took the cables off, went down to Advance and matched up top-post cables of similar length... and you can now let that truck sit for 2 months and it'll crank right up. I've done it several times. :)

bmwpower
03-15-2007, 10:46 PM
You want a quick no cost way to charge that battery? OK Heres an "old school" way to do it without spending a dime. Take your other car and crank it up. While running you remove the battery ,and dont let the connections touch anything. Then you pop in your dead battery and hook it up to the correct battery post. DONT CUT THE CAR OFF,because it is now charging the battery. let it run for approx 10 minutes and then cut the engine off and see if it will restart the car. If so your battery is now charged.

I don't see how that is any different than jumping the car with another car, except I don't have to use another car. Charging the dead battery may still kill the alternator, which I definitely don't need to do.

thefairlaneman
03-15-2007, 10:50 PM
I don't see how that is any different than jumping the car with another car, except I don't have to use another car. Charging the dead battery may still kill the alternator, which I definitely don't need to do. There is a differance. When you just connect cables the running car doesnt detect the low battery because its battery isnt low and is still in the circuit.........I think you best let a mechanic help you before you mess it up.

RAYJAY
03-15-2007, 11:25 PM
I got mine from sam's club best battery charger I ever had(have it about 2 years now )

2/10/25 AMP Charger with 75 AMP Engine Start

http://graphics.samsclub.com/images/products/0061797709504_L4.jpg

and at 49 bucks good deal

wilbilt
03-16-2007, 12:19 AM
New batteries are pretty cheap, too. I don't know what the situation is or what kind of car, but it could be an option? :dunno:

I have a red Optima in my truck that is nearly 7 years old. It still looks and performs like new. I'm getting a little worried about it due to the age, but it still starts. The truck has almost 300K miles on it, and I'm beginning to think the battery is going to outlast the vehicle.

bmwpower
03-16-2007, 05:59 AM
New batteries are pretty cheap, too. I don't know what the situation is or what kind of car, but it could be an option? :dunno:

I have a red Optima in my truck that is nearly 7 years old. It still looks and performs like new. I'm getting a little worried about it due to the age, but it still starts. The truck has almost 300K miles on it, and I'm beginning to think the battery is going to outlast the vehicle.

The battery is brand new. The car is old and probably has a short somewhere.

bmwpower
03-16-2007, 06:00 AM
There is a differance. When you just connect cables the running car doesnt detect the low battery because its battery isnt low and is still in the circuit.........I think you best let a mechanic help you before you mess it up.

No thanks. I don't need a mechanic to help me charge a battery.

MAD
03-16-2007, 09:07 AM
The battery is brand new. The car is old and probably has a short somewhere.

I have found that slow/overnight battery drain can often be traced to :

1- trunk light or glove box light staying on due to missing or broken plastic trim where button contacts, too much stuff in glove box, faulty switch, etc...

2- Sloppy aftermarket installation of alarm system or audio components. You never know where the installer tapped power from. There may be remnants of an old system giving you trouble. People are often not too careful about uninstalling stuff from cars they are about to sell.

good luck

ranger_dood
03-16-2007, 08:42 PM
You want a quick no cost way to charge that battery? OK Heres an "old school" way to do it without spending a dime. Take your other car and crank it up. While running you remove the battery ,and dont let the connections touch anything. Then you pop in your dead battery and hook it up to the correct battery post. DONT CUT THE CAR OFF,because it is now charging the battery. let it run for approx 10 minutes and then cut the engine off and see if it will restart the car. If so your battery is now charged.

Never, never, NEVER do this in any modern vehicle. You run a very high risk of frying the ECM/PCM. You've got no ground to the system!

thefairlaneman
03-17-2007, 09:33 PM
Never, never, NEVER do this in any modern vehicle. You run a very high risk of frying the ECM/PCM. You've got no ground to the system!
That is correct, but I gave an "old school" method so that has to be considered, Maybe he needs to call a mechanic

MAD
03-19-2007, 12:41 AM
You want a quick no cost way to charge that battery? OK Heres an "old school" way to do it without spending a dime. Take your other car and crank it up. While running you remove the battery ,and dont let the connections touch anything. Then you pop in your dead battery and hook it up to the correct battery post. DONT CUT THE CAR OFF,because it is now charging the battery. let it run for approx 10 minutes and then cut the engine off and see if it will restart the car. If so your battery is now charged.

Even for non-electronic vehicles, this old school method can be a bad idea. Unless you have a dc generator with an external regulator (not an alternator), you are just asking for fried diodes. That rules out most vehicles made after 1970 or so.

iiibdsiil
03-19-2007, 01:44 AM
Another idea is to get a jumper box. I have one that has a light, air compressor for filling up tires, I think it will work as a power inverter, and of course, it jumps cars. I got mine for like $60 at Costco, and although I've never had to use it for my own car, I have used it about 10 times for other people.

Of course, it becomes on of those things that if you don't keep it in your trunk EVERY DAY, you'll have a dead battery the day you don't have it ;)

bmwpower
03-19-2007, 06:05 AM
Another idea is to get a jumper box. I have one that has a light, air compressor for filling up tires, I think it will work as a power inverter, and of course, it jumps cars. I got mine for like $60 at Costco, and although I've never had to use it for my own car, I have used it about 10 times for other people.

Of course, it becomes on of those things that if you don't keep it in your trunk EVERY DAY, you'll have a dead battery the day you don't have it ;)

I DO have one of those. I just didn't think it would charge the battery. What if I plug the unit in the wall as I normally would to charge it and then plug in the battery clamp leads and place them on the battery? Maybe this would work??

I'll have to look for the manual...

HOTFR8
03-19-2007, 05:33 PM
Some of the good Jumper boxes also work as chargers or power supplies.
Just buy a good quality one and make sure it has surge protection.

Another option would be solar panel chargers that can be left on all the time. Again make sure they are a good quality version and have a diode that will not let them feedback and flatten the battery.