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Cozzer

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...car battery booster boxes.
(If you nip on to a certain well-known auction site and bang in "12v Portable Car Jump Starter Air Compressor Battery Start Booster Charger Leads" you'll see one.)

I've had 2 over the years. The first went kaput many years ago, but (like you do) I kept the charger, and put it safely in the drawer where the other 512 phone/torch/electric screwdriver wall warts reside. Before you say "Whoa!", I did tippex "Battery Pack" on the plug end....
A few years later, I bought another unit. Again, bright yellow, more-or-less brother chip with the eBay one above. Of course, it came with yet another wall wart....
A few months ago, a neighbour had need to borrow it - and it didn't work.
I hadn't charged it up in a while, so tried, but the battery within was too far gone. These are the same as fitted to mobility scooters and the like - this happened to be a 6-FM-17.
Ordered a new battery for it a couple of days ago - cheaper than buying a whole new unit - which arrived yesterday.
I guessed it needed charging, so played "hunt the charger"....
Found the tippexed "Battery Pack" one. It was right next to another marked....yes....you're ahead of me..... "Battery Pack".
No matter, I thought. I'll use ....this one.
A quick glance at both showed a difference, though.
It might not matter, but then again....
The output on one says "DC13.5V ====1000mA
The other shows "12V ==== 200mA"

The yellow box itself is no help whatsoever. No brand name, no label (now) and only shows the symbol for centre-positive (which both chargers do).

So which to use to top up the new battery, please?!
 

Terry - Somerset

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Start with the small low power one - it is less likely to cause damage.

If it doesn't work you cn always try they larger one.

It's what I would do - but what do I know!!
 

porker

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Problem is that if the correct charger for it is the larger 1A one then it may draw too much current from the 200mA unit and cause it to fail or overheat. I would actually use the larger one as it will only draw what it needs. Problem is you may never know if it the correct one. I assume the way you wrote there specs that they are both DC. I am assuming they are.
 

HamsterJam

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200mA seems like a very low current to be charging a 17Ah battery with. Are you sure it is the right wall wart?
Assuming the full 200mA can be delivered (in practice it won’t) thats 17x5=85hrs (3.5 days) to charge from zero to full and in practice a fair bit longer.
Also with just 12volts you will never fully charge a 12v battery. It needs to be a bit higher to shove the charge in.
 

Jameshow

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Pipped to the post!

12v isn't the correct voltage for charging a 12v lead acid battery. 13.7 - 14.4v is what a alternator / battery charger will put out.

1A isn't a great deal of current it's still going to take 17hrs to charge a small lead acid battery.

Cheers James
 

Cozzer

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200mA seems like a very low current to be charging a 17Ah battery with. Are you sure it is the right wall wart?
Assuming the full 200mA can be delivered (in practice it won’t) thats 17x5=85hrs (3.5 days) to charge from zero to full and in practice a fair bit longer.
Also with just 12volts you will never fully charge a 12v battery. It needs to be a bit higher to shove the charge in.
Hence my question!
I don't know which charger came with the newer booster, as they are both marked (by me) the same. One was kept from the old booster, and the other will be for the newer one.
From your (very helpful - thanks!) reply, and the post below yours, 'twould seem that the 13.5v job is the correct one.
 

baldkev

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My satnav charger died once while we were away. No problem!!!! I had a disposable 12v extension thing, so i decided to cut the satnav charger plug off and join it to the extension lead cables ( both were sealed plugs )
Well i cut the satnav lead and extension lead, bared the wires, then realised something..... the satnav lead was all black, whereas the extension was 1 black, 1 grey. pipper. 50/50!!!
It worked for a few seconds then the satnav started smoking! I got it out the window just in time 🤣
 

Cozzer

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Of course, in retrospect, it would've perhaps been easier to ask
"Has anybody got one of these?"
and, if so,
"can you have a gander at the wall wart and tell me how it reads?"!


Edit : in fact, that's not a bad idea! Start another thread with "Anyone got one of these?"!
 
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Cozzer

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Hmmmmm.....

I'm even more confused now!
If you have a gander at this one -
and the range of photo's, you'll see that (for once) there's a photo of the accessories including its charger.
Notice it's marked with a (only) 12v output and 800ma, which as HamsterJam above said, doesn't seem to make much sense?

I should point out that it's not exactly the same model as mine - mine doesn't have the air compressor gadget (as most now seem to have), but the casing and controls on the front are identical.
 

DrPhill

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I have one of these devices - not the same make but a similar idea. It can start a car engine (even diesel up to 2.5l !). It charges from a 5v usb charger. Go figure.... I guess that there is some internal electrickery that makes it paossible. Perhaps the cells are charged in parallel and discharged in series?

It works (except when the car battery is completely dead). It also works as a portable power pack for mobile phones.
 

Cozzer

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I have one of these devices - not the same make but a similar idea. It can start a car engine (even diesel up to 2.5l !). It charges from a 5v usb charger. Go figure.... I guess that there is some internal electrickery that makes it paossible. Perhaps the cells are charged in parallel and discharged in series?

It works (except when the car battery is completely dead). It also works as a portable power pack for mobile phones.
Hey! Less of the intelligent technical stuff!
Seriously though, thanks for your suggestion. I'm even more baffled now, with your comment about the 5V usb job!
Yes, I've actually used one in the past, and they're a godsend when required. For the minute, the newly fitted 'storage' battery is virtually fully charged, showing just over 13v, so I've no need to top it up....but I know that if you've used it a couple of times, it pays you to recharge....and we're back to the quandary again!
Out of interest, when I replaced the internal battery a couple of days ago, there is a small PCB inside, so you may be right about the electrickery. Didn't look exactly sophisticated though....
 

porker

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I took a quick look at the linked item above. It contains a 7Ah battery which is much smaller than a typical car battery but can potentially deliver enough amps to crank the engine to start it. 7Ah means the battery could deliver 7A for 1 hour or in theory 420A for 60 seconds. In practice it can't, due to other factors like internal resistance of the battery for example, but it can deliver a high current for a few seconds - enough to turn over an engine. (I would take the numbers with a pinch of salt but it takes a lot of amps to crank an engine). The charger is specified as 500mA (0.5A) so assuming no losses it would take 14 hours to charge the internal battery from flat.
It is fairly simply to convert the voltage from 5V USB to 12V using electronics (a boost converter)
 

Cozzer

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I took a quick look at the linked item above. It contains a 7Ah battery which is much smaller than a typical car battery but can potentially deliver enough amps to crank the engine to start it. 7Ah means the battery could deliver 7A for 1 hour or in theory 420A for 60 seconds. In practice it can't, due to other factors like internal resistance of the battery for example, but it can deliver a high current for a few seconds - enough to turn over an engine. (I would take the numbers with a pinch of salt but it takes a lot of amps to crank an engine). The charger is specified as 500mA (0.5A) so assuming no losses it would take 14 hours to charge the internal battery from flat.
It is fairly simply to convert the voltage from 5V USB to 12V using electronics (a boost converter)
Cheers for that - good of you.

Bear in mind that if I had another three brain cells I would be a daffodil bulb, I take it that my booster box's battery (a 6-FM-17) means it could deliver 17A for 1 hour, or 1020A for 60 seconds?
Going back to my quandary of which of the two chargers is the correct one - (one of them is definitely right for the box, and the other should've been dumped when the original box of tricks failed) you're warned that after every use the booster box should be charged up in readiness for the next use. In other words, it should never be allowed to discharge fully.
So I'm back with the (same) question! Which charger to use?!
Output DC13.5V ====1000mA
or
Output DC12V ==== 200mA
 

baldkev

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Is the manufacturer still alive? If so, you might be best phoning or emailing them with the question
 

Cozzer

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Is the manufacturer still alive? If so, you might be best phoning or emailing them with the question
Eh?
Still alive?!

No name on the box. These things are like the Aldi/Lidl/etc. DIY stuff, churned out in their thousands and then branded whatever. Trouble is that they invariably just have sticky labels affixed, which drop off over the years!
Hence thinking/hoping someone else on here might have one similar and be able to have a look at their charger!
 

baldkev

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As in still in business 😄 i wasnt suggesting you find the guy who was on the production line that day......

On the other hand, how much is a new one? If its 20 quid, just take a gamble with the charger ( do it outside )
 
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