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Old Yesterday, 05:21 AM
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Please help to identify battery configuration

Hi all,

I doubt this is easy to answer, but perhaps someone would be able to help me with this; especially if they do own one of these themselves.

Here's the problem. The charging cuts off at 12v (which I doubt is the battery's full capacity). So I guess the charging circuit doesn't know when it's actually full.

The battery is listed as 38,000mAh but we all know that's not true.

When the charging cuts off, the battery level indicator only shows 3/4 LEDs, which is annoying. The product is poorly designed.

Here's how much capacity I've got out of it:

I got it up to 12v. Jump started my boxer 3 times. Took it back in to charge a Nokia Lumia via USB. Then connected the 12v output to a universal Li-Ion charger to charge a small 3.6v cell. The charging cut off halfway because the power bank fell to 11.5v. At this point the battery indicator shows 2/4 LEDs. I then used the cable clamps to draw 12v at 2.5amps to turbo charge a set of 4 AA NiMH cells which took 15 minutes.

At the end of all these the indicator dropped to 1 light.

I would like to charge it up properly using an external charger like the IMaxB6, however to use it I need to know the battery's chemistry and capacity.

Do the output wires look like balancing leads? The look a lot for a 3S1P.

Also, I'm guessing this is Li-Po.

Any advise would be greatly appreciated.

Thanks in advance.

http://freeimagehosting.nl/site2/image.php?di=M4IW

http://freeimagehosting.nl/site2/image.php?di=5EJV
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Old Yesterday, 06:57 AM
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Letchworth, Great Britain (UK)
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It certainly doesn't look like 38,000mAh capacity, but a link to the product's web page might help.

If it's marketed as an emergency jump-start device, then I would say you were lucky to get three starts out of it before it needs recharging. If it's a 3S LiPo then, as you probably know, fully charged voltage should be 12.60. But maybe the charger only goes to 12v because LiPos don't like to be stored fully charged. (Thinking about it, LiPo isn't a really good choice for an "emergency" battery, for that reason.)
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Old Yesterday, 07:07 AM
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Quote:
Originally Posted by abenn View Post
It certainly doesn't look like 38,000mAh capacity, but a link to the product's web page might help.

If it's marketed as an emergency jump-start device, then I would say you were lucky to get three starts out of it before it needs recharging. If it's a 3S LiPo then, as you probably know, fully charged voltage should be 12.60. But maybe the charger only goes to 12v because LiPos don't like to be stored fully charged. (Thinking about it, LiPo isn't a really good choice for an "emergency" battery, for that reason.)
Hi,

I didn't include the product page as most of these Chinese listings can't be trusted anyway, however here it is:

http://www.aliexpress.com/snapshot/6433500347.html

I guess LiPo is ideal for jump starting because of its high discharge rate. It only takes a little bit of energy to start a car but the discharge rate needs to be very high to supply 400Amps peak.

Yeah I'll try to see if I can push it to 12.x volts using an external charger like the IMax B6. The problem is, the charger needs to know the battery's capacity which I don't know. I'll see if there's a way to charge it without knowing the capacity.

In terms of voltage and chemistry, I'll select LiPo at 11.1V just to be safe. I guess selecting normal Li-Ion would be more dangerous as the charger would try to push the battery up to a higher voltage.

What do you think?

Thanks.
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Old Yesterday, 04:09 PM
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The web page in your link is "not available" for me.

As for charging, a normal LiPo charger will take a 3S pack up to 12.60v for full charge, that's why I suggested they may be holding it down a little with your device, for longer life. 11.1v (i.e. 3.70v per cell) is the nominal voltage, at which point the LiPo has practically no useful charge left. Most chargers on a Li-Ion program would take a battery to around 3.60 or 3.65v per cell at full charge -- significantly less than for a LiPo.
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Old Yesterday, 05:26 PM
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Quote:
Originally Posted by abenn View Post
The web page in your link is "not available" for me.

As for charging, a normal LiPo charger will take a 3S pack up to 12.60v for full charge, that's why I suggested they may be holding it down a little with your device, for longer life. 11.1v (i.e. 3.70v per cell) is the nominal voltage, at which point the LiPo has practically no useful charge left. Most chargers on a Li-Ion program would take a battery to around 3.60 or 3.65v per cell at full charge -- significantly less than for a LiPo.
Hi there,

Not sure why that URL didn't work for you. Please try this one on eBay. It's identical to mine:

http://www.ebay.co.uk/itm/38000mAh-J...item5d535a33bb

Yeah I get the problem now. When my charger arrives, I'll try charging it using an 11.1v LiPo program. Hopefully it'll do the right thing and bring it up to 12.6v. Due to the dodgy way they've wired the balancing lead, I've got to charge it through the main output lead unbalanced. I hope this wouldn't be much of an issue as the pack is still new so presumably all 3 cells are of equal health.

Will see what happens
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Old Today, 03:41 AM
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That link works okay, but there's not much in the way of technical detail.

Anyway, the only other thing I can add is I think they've surely put one too many zeros on the mAh capacity.
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Old Today, 06:27 AM
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Quote:
Originally Posted by abenn View Post
That link works okay, but there's not much in the way of technical detail.

Anyway, the only other thing I can add is I think they've surely put one too many zeros on the mAh capacity.
Hahahah yeah definitely. Even much lower capacity LiPos come in plastic boxes that look like SLA type batteries. There's no way 38,000 would fit in a tiny package like this
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Old Today, 09:59 AM
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Dayton Intl, Ohio, United States
Joined Jan 2000
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I was looking at something similar on Amazon the other day. I was going to buy one, but very little information is included so I decided against it. They all seem to have very large capacities listed for the size. It looks like the cells have a series connector for car starting and parallel connector for use charging and they list the total parallel capacity - very misleading. My guess is that they're lithium ion, but none of the one's I saw listed the battery other than "lithium"

Azarr
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Old Today, 10:34 AM
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Originally Posted by Azarr View Post
I was looking at something similar on Amazon the other day. I was going to buy one, but very little information is included so I decided against it. They all seem to have very large capacities listed for the size. It looks like the cells have a series connector for car starting and parallel connector for use charging and they list the total parallel capacity - very misleading. My guess is that they're lithium ion, but none of the one's I saw listed the battery other than "lithium"

Azarr
Yeah the listings are dodgy. You're probably paying too much on Amazon anyway. Try AliExpress as there are many sellers there.
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Old Today, 12:05 PM
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Hobby king has one for $52. It's listed as lithium cobalt oxide.

Azarr
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