12 to 6 Volt converter

[irishbiker]

I'm off to Germany with a few of the Sunbeam guys. As I'm the only one with a 12 volt system one of the members has asked if its possible if I can keep his spare gel battery topped up.

My bike has already got a 12 socket so I was wondering if anyone has heard of a 12 Volt to 6 Volt converter? I had thought about using a phone charger, give it a trickle charge of 5volts @ 750ma or is that too little a charge to make any difference?


P.

[John Hopkins]

Just google dc - dc voltage converter, should be about a tenner.

But why not pick up a cheap 6v charger in germany?

John

[4_stroke]

One way is to get an inverter to convert 12 volts to 240 then a charger to drop the 240 down to 6 again. The 12v-240v inverters are cheap on e-bay. Just hook a cigar lighter socket to your battery.


Inverter
http://cgi.ebay.co.uk/175W-CAR-12V-DC-240v-AC-POWER-INVERTER-Free-UK-P-P-/290393592623?cmd=ViewItem&pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item439cce932f

Charger
http://cgi.ebay.co.uk/MOTORCYCLE-SCOOTER-BATTERY-CHARGER-6-VOLT-12-VOLT-/350271273033?cmd=ViewItem&pt=UK_Motorcycle_Parts&hash=item518dcb7849

I have located a 12 volt lighter socket under my seat. Its great for charging mobiles, connecting to a charger etc.

[irishbiker]

Its been a long day, I should have thought of that. Thanks John.

[irishbiker]

Thanks again 4_stoke and John.

We don't know where we will be staying so we are not sure about power. I don't mind trickle charging a 6 volter esp if its a gel battery. Won't leave it on for the whole journey of course. I think one of the lads is bringing a charger as well, this will prob be used as a backup.

Seen this one on the interweb

http://www.beststuff.co.uk/dc_voltage_conversion.htm

Minwa Upswing MW215

It will pump 6volts at about 1500mA.

[4_stroke]

Remember that it takes around 2.35 to 2.5 volts per cell to charge a battery. A 6 volt battery has 3 cells. A regulated 6 volt supply will only produce 6 volts so will not actualy charge a battery. If its an unregulated 6 volts it will probably work as the peak voltage is much higher.

[harry]

How about.

Tell him to buy two batteries, connect them in series an' charge them straight off 12 volts.

This idea is either total genius or............... the ravings of a loony.

You chose :thumbsu:

[irishbiker]

Remember that it takes around 2.35 to 2.5 volts per cell to charge a battery. A 6 volt battery has 3 cells. A regulated 6 volt supply will only produce 6 volts so will not actualy charge a battery. If its an unregulated 6 volts it will probably work as the peak voltage is much higher.


Thanks, tho I thought as long as it was getting current it would trickle charge. I can select 7.5V with the unit.

And Harry I had thought of that as well, great minds and all of that ;). I think the current might cook the batteries

[4_stroke]

How about.

Tell him to buy two batteries, connect them in series an' charge them straight off 12 volts.

This idea is either total genius or............... the ravings of a loony.

You chose :thumbsu:

This could work.......... But!

So long as both batteries are in the same state of charge. If they are imbalanced the result could be a damaged battery. This happens on 24 volt truck systems that use 2x12 volt batteries. The state of charge of the two batteries has to be balanced.

[harry]

This could work.......... But!

So long as both batteries are in the same state of charge. If they are imbalanced the result could be a damaged battery. This happens on 24 volt truck systems that use 2x12 volt batteries. The state of charge of the two batteries has to be balanced.

Ah yes good point. :o

You'd need summat to balance both batteries. It could be done by connecting them in parallel with a bulb between them as a resistor, wait till the bulb goes out then put 'em in series and charge.

But............ getting kinda messy innit.

[johnr]

How about.

Tell him to buy two batteries, connect them in series an' charge them straight off 12 volts.

This idea is either total genius or............... the ravings of a loony.

You chose :thumbsu:


exactly what i was going to suggest, and thus, total genius!!:D

[johnr]

Thanks, tho I thought as long as it was getting current it would trickle charge. I can select 7.5V with the unit.

And Harry I had thought of that as well, great minds and all of that ;). I think the current might cook the batteries

no it wont, all your 12 battery is, is 2 6 volt ones in the same case, or 4 3v ones, but you get the drift. my mates old austin had 2 big 6v batteries connected to give him 12v. as long as the two batteries are the same, then it will work and charge up fine.

[4_stroke]

as long as the two batteries are the same, then it will work and charge up fine.

It works if both batteries as permanantly connected together at all times and are charged and discharged together. But if you have one part charged and one flat, thats a different matter.

As mentioned above they have to be the same AND be at the same state of charge. If not there will be a voltage imbalance accross the two batteries that could overload the one with the greater state of charge.

[wurzel]

like the issues you have when a cell goes down in a battery, because most 12v batteries are really 6 2v batteries