Charger/adaptor question

Hightower · 21 September 2011, 20:40

I've just bought a Colman Hi performance rechargable Air Blower. It arrived today, but after I unpacked it I noticed the charger was an American adaptor 120v input

Anyway, the seller has offered compensation to the tune of a new adaptor, the only ones I can find are universal types for a £5er.

Specs for the charger is output : 7.5v dc 200ma

The universal Specs are: 7.5V dc but 300ma

Now the question is, will a 300ma output damage the electrics/lead acid battery at all?

The reson I ask is the wording in the ad on ebay Link look at the Warning part.

It reads: This unit maximum rating is 300mA and if less current is drawn, there is a corresponding voltage rise. At less than 150mA this rise could be considerable

Anyone in the know help?

guernseylee · 21 September 2011, 20:57

Quote:

Originally Posted by Hightower

I've just bought a Colman Hi performance rechargable Air Blower. It arrived today, but after I unpacked it I noticed the charger was an American adaptor 120v input

Anyway, the seller has offered compensation to the tune of a new adaptor, the only ones I can find are universal types for a £5er.

Specs for the charger is output : 7.5v dc 200ma

The universal Specs are: 7.5V dc but 300ma

Now the question is, will a 300ma output damage the electrics/lead acid battery at all?

The reson I ask is the wording in the ad on ebay Link look at the Warning part.

It reads: This unit maximum rating is 300mA and if less current is drawn, there is a corresponding voltage rise. At less than 150mA this rise could be considerable

Anyone in the know help?

goto maplin electronics get a uk adaptor ............

Courageous · 21 September 2011, 21:21

Andy don't fart about with chargers. You may already know that chargers for lead acid are completely different to those for Ni-cad units etc, some constant voltage and others constant current. I would personally leave this field well alone. For my money I would be looking at a step down transformer for the mains. Something similar to this:

Voltage Converter 220V To 110V Travel Power Transformer Regulator Adapter 100W | eBay

captnjack · 21 September 2011, 23:28

Its will be fine, just charge a little faster than it should. Not knowing the battery capacity its hard to tell if this will be a problem but I doubt it. Normally charging at 20% of Ah capacity is ok. So as long as the lead acid battery is 300x5 = 1500mAh or GREATER (=1.5Ah which is tiny) you won't be overcharging and getting too hot. This must be a nominal 6V battery.

The warning seems to refer to the voltage rise which is required by a lead acid taper charger to achieve full charge. With a taper charger, it takes more and more voltage to "push" the last bits of charge into a battery nearly full. I could be mistaken the wording/warning is very strange.

Hightower · 22 September 2011, 00:02

I got confused by the warning too!

But my understanding is that the battery will take exactly what it needs. The ac/dc adaptor's maximum charging current is 300ma and obviously if the battery needs more amps it will take it at the maximum of the Charger which is 300ma so will charge very slightly faster.

So by that reckoning I think the charger should be fine for charging a 6v battery. Correct me please if I'm wrong.

Courageous · 22 September 2011, 05:54

"Correct me please if I am wrong"

Courageous · 22 September 2011, 06:02

Andy, just to clarify for me please. The unit you have is a charger, the outlet of which plugs into the blower which simply houses the motor,fan and battery is this correct? If so then the "unit" we are talking about is a battery CHARGER not an adaptor. An adaptor such as you are looking at on ebay is a power supply unit only it does NOT operate as a charger for batteries. These are two completely different items in my opinion. Being a power supply unit will get it to "charge" a battery in a rather ineffective way but it will eventually feck it and worse it is possible it could overcharge, overheat and potentially catch fire IMHO.

But it's your risk of course. Strikes me you already made your mind up

Leapy · 22 September 2011, 07:41

Quote:

Originally Posted by Hightower

Correct me please if I'm wrong.

Voltage adaptor...no risk...but bear in mind you need 240v to 110v not 110v to 240v

Alternative 240v charger per your eBay link...risk unknown...could be none, more likely could be some...personally, I wouldn't go there. Nothing more dodgy than badly worded low cost eBay electronics

Courageous · 22 September 2011, 09:21

Thank you Leapy, except it's NOT a charger!

My concern is at the point when the current draw is minimal (ie battery fully charged) exactly what voltage will the adaptor allow it to rise to? This is the reason for the warning as stated. There is a point at which even with little current the battery will fry. If life was so simple why would we all be paying more for battery chargers instead of a simple transformer and a rectifier?

Is the extra fiver the problem Andy? Is it the fact that it's in HK? Maybe maplins do a similar transformer at a reasonable price. It is the right device for the job. Anyhow, as we say - your risk. Good luck with it anyhow.

BogMonster · 22 September 2011, 09:36

'Borrow' a site transformer designed for 110V power tools

FWIW I agree 100% with not using a power supply as a charger - cheap rubbishy power supplies usually have very poor voltage regulation and as the load comes off, the voltage goes up... maybe till it lets the smoke out. Good regulated power supplies usually cost 10x what a cheap one does for a reason! From the warning text you posted it sounds like the £5 model falls into the first category.

Your choice but it might be cheaper getting a converter than buying a new house

Leapy · 22 September 2011, 09:54

Quote:

Originally Posted by Courageous

Thank you Leapy, except it's NOT a charger

Slip of the mouse

Courageous · 22 September 2011, 10:24

Cheaper than buying a new house?

Playmobil Toy Dolls House NEW - modern house park toy | eBay

Or may be not!

Hightower · 22 September 2011, 15:08

I haven't made my mind up about anything, I'm just trying to understand something.

Shown in the picture is the AC/DC adaptor that was supplied to charge the blower. All I was ever after was a replacement for this but with a 3 pin 240v input.

Is this one of those adaptors that you are telling me to leave well alone?

jyasaki · 22 September 2011, 15:43

Hightower, is your inflator something like what's sold for air beds? A little handheld job?

If so, the wall wart is simply charging the NiCad (or possibly NiMH) battery contained within. I wouldn't worry about any rise in voltage from the replacement charger. Most wallwarts aren't all that accurate anyway, despite their specs. You'll likely be off by less than half a volt from drawing less than the rated current (which is spec'd more as a max anyway), which is probably less than the tolerance of the OEM wall warts anyway.

If you're worried about it, a travel transformer would allow you to use the OEM transformer with the UK power. Personally, I think that any voltage near the 7.5V (say, 7 to about 9V) would be fine.

jky

Pikey Dave · 22 September 2011, 17:00

Have you tried contacting Coleman UK & asking if they have the UK charger available to buy, problem solved

free · 22 September 2011, 17:47

HT, I think I can see your wood through all the trees

Choose any 3 pin UK tranny, with a 7.5V output and rated at least 200mA, you've probably got a garage full of them. If it's got the wrong end on it, just cut the cables and re-splice, remembering polarity. If it's more than 200mA, you're right, it's the maximum current capacity of the output stages, not the power, as we all know that would be measured in Watts. Christ knows what the warning in the ebay ad is all about, I'd read it as "made cheaply, and inappropriately."

Don't buy that cheap crap from ebay, if you must, pop into Maplins, though I've not had much joy with their variable voltage ones in the past.

free

Courageous · 22 September 2011, 18:07

A split decision then...... Andy the unit you pictured looks to be a normal power adaptor rather than a charger. Go for it!

captnjack · 22 September 2011, 19:01

Cripes now I'm confused, I thought there was a battery in this blower to use it away from the wall socket?

But the pictured adapter does not appear to be a charger. It might be, the output voltage is about right to charge a 6V battery.

Poly · 22 September 2011, 19:14

Quote:

Originally Posted by captnjack

Cripes now I'm confused, I thought there was a battery in this blower to use it away from the wall socket?

But the pictured adapter does not appear to be a charger. It might be, the output voltage is about right to charge a 6V battery.

You are correct. It's quite common on cheaper stuff to just charge from a dc supply like this. If its a bit more expensive it may have some charging electronics inside the pump casing.

Hightower · 22 September 2011, 19:15

Here's the really frustrating bit.

Do you want to know?

I've just dug this out of the garage Charger.

I thought it was just a Nicad Lipo charger, but reading the manual it does Lead acid batteries too. All I need is some leads with 4mm banana plugs at one end and a 5.5mm adaptor in the other and away I go.