Car battery jump starters - portable? plugin?

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geekIT

2378 posts

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#224278 10-Nov-2017 11:06

Having two cars with flat batteries yesterday (so no jump-starting possible) I started looking at jump alternatives and was surprised to find how many gizmos are on the market now.

Like - when I last looked, several years back - the tiny Lithium kits weren't available.

So, as my old wagon will soon be going to Toyota Heaven, I won't have any backup next time I leave the ute's parking lights on.

Recommendations would be appreciated.

'Those who can make you believe absurdities can make you commit atrocities.' Voltaire

'A patriot must always be ready to defend his country against his government.' Edward Abbey

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1604 posts

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#1898831 10-Nov-2017 11:49

I have been similarly caught short, put my 10 amp charger on the battery and 30 minutes later the engine could be started. I now have a no name lithium jump pack but I've only jumped motor bikes with it so far so can't fully recommend this brand yet.

I think every geek and car guy should have a battery charger in their cache of tools.

Ideally you should put the battery on a charger overnight after flattening. Although the ute battery will have sufficient charge to start the vehicle and get you on your way, the battery won't be back up to fully charged, as it takes about 8 hours engine running to 80% charged and another 8 -16 hours to get the last 20% in. The whole time you battery is less than 100% charged, the plates are sulphating or aging, which is stealing battery capacity and life. It may take 2 tanks of gas/2 weeks before your battery is back fully charged if it is only receiving charge from the alternator, but you can easily fully charge the battery overnight/in a day with a charger.

Added consideration is that because the battery is presently lower than normal, you might not get away with things that are not normally a problem, such as leaving the lights on while grabbing some milk from the diary, or listening to the radio while awaiting the other half to finish shopping.

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allio

883 posts

Ultimate Geek

#1898832 10-Nov-2017 11:49

I have a seldom-used car with a tiny battery that’s prone to going flat (Honda Jazz) so frequently have to deal with this. I bought a typical Repco 900 amp jump starter and it does the job fine. After I used it a few times the battery got so sick it stopped holding a decent charge. I then bought a Ctek MXS 5.0 charger and ran it through a recondition cycle – basically a long slow controlled overvolt, causing the liquid in the battery to bubble and mixing everything up. This revitalised my battery. I now plug it in to charge overnight every month or two and it keeps ticking along. Don’t think I’ve used the jump starter since I got the Ctek, and if I could go back in time I wouldn’t have bought it at all. The Ctek leaves the battery far healthier than jumping + any amount of driving could do.

That said those compact lithium ones do look very handy for jumping other people’s cars and generally acting as an emergency power source – I'd be interested to hear how well they work.

Coil

6614 posts

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#1898834 10-Nov-2017 11:52

Those cheap lithium ones are not what they advertise at all. Many youtube videos on it.

Get a new car battery of the appropriate spec and enjoy 4-5 years of faultless starts. Heck, My beema can last all night with all the cabin lights on and still crank over as if she was 100% the next day.

davidcole

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#1898836 10-Nov-2017 11:54

I've got a charger like this: http://www.supercheapauto.co.nz/Product/SCA-Smart-Battery-Charger-3-Stage-12-Volt-1-6-Amp/343260?menuFrom=1021637

Luckily my car has external terminals and tend to leave the car on this chargers as it's not used often during the week.

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Coil

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#1898922 10-Nov-2017 14:21

davidcole:

I've got a charger like this: http://www.supercheapauto.co.nz/Product/SCA-Smart-Battery-Charger-3-Stage-12-Volt-1-6-Amp/343260?menuFrom=1021637

Luckily my car has external terminals and tend to leave the car on this chargers as it's not used often during the week.

Car has external terminals? Aye?

My car has the battery in the boot and a jumper under the bonnet which isolates to starting sequence and doesn't power accessories.
Never heard of battery terminals outside of the car? Mind letting me know so I can go round with some wire and cause havok?

davidcole

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#1898926 10-Nov-2017 14:24

Coil:

davidcole:

I've got a charger like this: http://www.supercheapauto.co.nz/Product/SCA-Smart-Battery-Charger-3-Stage-12-Volt-1-6-Amp/343260?menuFrom=1021637

Luckily my car has external terminals and tend to leave the car on this chargers as it's not used often during the week.

Car has external terminals? Aye?

My car has the battery in the boot and a jumper under the bonnet which isolates to starting sequence and doesn't power accessories.
Never heard of battery terminals outside of the car? Mind letting me know so I can go round with some wire and cause havok?

Well externalish. Like yours. Exposed terminals under bonnet and battery in boot. Just leave the car in the garage with the bonnet up. Wish I could plug an induction charger to it.

geekIT

2378 posts

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#1898939 10-Nov-2017 14:41

Re conventional battery charging, my Toyota handbook says that instead of connecting the charger's pos and neg terminals to the battery, I should connect the pos only to the battery, disconnect the battery's neg terminal then connect the charger's neg terminal to the chassis.

Anyone know why this method is considered important? The manual stresses that this method should be followed but doesn't say why.

'Those who can make you believe absurdities can make you commit atrocities.' Voltaire

'A patriot must always be ready to defend his country against his government.' Edward Abbey

Mattmannz

471 posts

Ultimate Geek

#1898958 10-Nov-2017 15:06

geekIT:

Re conventional battery charging, my Toyota handbook says that instead of connecting the charger's pos and neg terminals to the battery, I should connect the pos only to the battery, disconnect the battery's neg terminal then connect the charger's neg terminal to the chassis.

Anyone know why this method is considered important? The manual stresses that this method should be followed but doesn't say why.

If you disconnect the battery from the chassis and then connect the charger to the chassis you won't recharge the battery.

frankv

5678 posts

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#1898977 10-Nov-2017 15:57

The idea of connecting the negative lead to the chassis rather than to the battery terminal is that in theory there could be hydrogen gas around the battery, and connecting the second lead could cause a spark, which could ignite the hydrogen.

If you connect the second lead to somewhere other than the battery, then there's no chance that the spark and hydrogen will coincide.

But, yes, disconnecting the battery negative from chassis would prevent charging. And reconnecting it is likely to cause a spark or two.

geekIT

2378 posts

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#1898980 10-Nov-2017 16:04

Sorry, I'm confused.

Are you saying that it's safer to connect the charger's neg connector to the chassis, but the battery's neg terminal shouldn't be disconnected?

'Those who can make you believe absurdities can make you commit atrocities.' Voltaire

'A patriot must always be ready to defend his country against his government.' Edward Abbey

scottjpalmer

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#1898994 10-Nov-2017 16:46

geekIT: Are you saying that it's safer to connect the charger's neg connector to the chassis, but the battery's neg terminal shouldn't be disconnected?

Yes

geekIT

2378 posts

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#1899131 11-Nov-2017 09:24

Got it. Cheers

One more question about charging batteries the conventional way:

After I completed flattened the battery on my 2005 Toyota, I connected my trickle charger, hoping that it would come back fairly quickly. But no, the ignition and dash lights worked after an hour or so, but it took around 5 hours before it would start the engine.

But it seemed to revive with a rush in the last 2 hours of the 5, as it sounded pretty juicy when it turned the engine over, whereas not much earlier, turning the key did zip.

Anyway, my question is: I only charged the battery for that period - 5 hours. Then I drove it a couple of kilometers down to the shops and back and it hasn't done any trips since. But it still starts ok now, which is two days later.

But I'm wondering if I should now give it a full overnight charge (or longer) to fully top it up?

'Those who can make you believe absurdities can make you commit atrocities.' Voltaire

'A patriot must always be ready to defend his country against his government.' Edward Abbey

BlinkyBill

1443 posts

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#1899147 11-Nov-2017 10:30

You’ve got a trickle charger, why wouldn’t you charge to 100%?

Sideface

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#1899148 11-Nov-2017 10:36

geekIT:

<snip>

But I'm wondering if I should now give it a full overnight charge (or longer) to fully top it up?

It takes at least 48 hours to fully recharge a flat battery with a trickle charger - eg overnight on several consecutive nights, or over a weekend.

If the battery is old and stuffed, it may no respond to a trickle charger at all.

Sideface

Aredwood

3885 posts

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#1899226 11-Nov-2017 12:28

It depends entirely on how much current the charger can provide and what the batteries Amp Hour capacity is. Rule of thumb is to charge for 12 hours at 0.1 X the AH rating. E.g. charge a 90 AH battery at 9 amps.

More on charging lead acid batteries. [url=]http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery[/url]

Also a lot of cars on purpose under charge their batteries to reduce alternator load and therefore improve fuel economy. They often will also run a really high charge voltage when the car is engine braking, as a rudimentary means of regenerative braking. So in a lot of new cars, It is unrealistic to expect a battery to last 5+ years like how they used to.

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