Charger/adaptor question

[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?

[guernseylee]

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]

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]

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]

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]

"Correct me please if I am wrong"

[Courageous]

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]

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]

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]

'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