Graupner Ultramat Charger

[Malakite]

Hi Guys,

I wonder if anyone can help. I have an array of different batteries, and although I know how to charge my basic 7.2v batteries for my model cars, I wondered if anyone know the correct voltage I should be putting through a couple of different batteries I have: One for a hovercraft which is an Ni-Mh AA 700mAh 9.6V 100611 and the other is for a Motorcycle which says 'Charge cycle 7.2v-7.5v and Standby Use 6.75-6.9?? It also says 6V4AH/20HR - does this mean its usually a 20hr charge via the plug in charger that came with it? Obviously the Graupner can charge them faster but I need to make sure I get the correct settings or I'll fry the batteries!

Thanks in advance

[mike_o]

If it's a NiMH or NiCd battery, you won't fry if it you limit the charge current just a little. The charger will detect full (delta peak) and go to trickle charge. If I'm not in a hurry, I'll limit the current to a 1/5 or a 1/10 of the capacity (700mAh -> 70-140mA charge).

The bike battery specs sounds like it's a SLA (Sealed Lead Acid) which the charger could kill!!!

Does the Ultramat have a timer? If so, set it for 700mA and limit the timer to 6 hours / 300 minutes for a full charge of a flat battery. The charger may not like the "taste" of the battery, though, and cancel charging.

[sosidge]

If the Graupner has a lead-acid mode (a lot of higher-end chargers do) then it should charge the bike battery quite happily. I'd advise reading the manual or contacting Graupner for a copy.

I'm sure the hovercraft battery could be charged in the NiMH mode, usually a fast charge current would be 1C so 700mA (or less) in that case. I would switch off the trickle charge feature if possible when using the fast charge setting.

To do a trickle charge, choose a current of 0.1C (70mA) and it should be charged in 12-14hrs. You can actually leave a NiMH cell on trickle charge forever because once the cell is full, the amount of energy lost through heat equals the amount of energy put in.

[Malakite]

If the Graupner has a lead-acid mode (a lot of higher-end chargers do) then it should charge the bike battery quite happily. I'd advise reading the manual or contacting Graupner for a copy.

I'm sure the hovercraft battery could be charged in the NiMH mode, usually a fast charge current would be 1C so 700mA (or less) in that case. I would switch off the trickle charge feature if possible when using the fast charge setting.

To do a trickle charge, choose a current of 0.1C (70mA) and it should be charged in 12-14hrs. You can actually leave a NiMH cell on trickle charge forever because once the cell is full, the amount of energy lost through heat equals the amount of energy put in.

It's got crocodile clips which I could attach to the motorbike battery, but I'm actually wondering if they are to attach the charger to a 12V battery such as a car battery if you were out - do you know at all?? Perhaps it can be used for either?

Many thanks

[mike_o]

The Ultramat is a dual-supply charger; It can be operated via the 110/230V mains or via an external low voltage, 12V - normally a car battery - supply. The croc clips are for this - they will not provide an output. Could you please state the xx number of the Ultramat XX charger? Then it will be easier to answer your questions.

[Malakite]

The Ultramat is a dual-supply charger; It can be operated via the 110/230V mains or via an external low voltage, 12V - normally a car battery - supply. The croc clips are for this - they will not provide an output. Could you please state the xx number of the Ultramat XX charger? Then it will be easier to answer your questions.

Hi guys - huge delay in this response!! I have an Ultramat 14. Any ideas if it's poss to charge the '6V4AH/20HR' battery from this charger? Can I use the crocodile clips as an output? If not hook it up to the 2 x standard output leads that I would usually have the banana plugs coming from?

At the moment I have the battery taking a couple of days to charge via its trickle charger and it never seems to charge it fully - so any help with this would be fantastic.

Thank you kindly.

[Malakite]

Sorry to be a pain, any ideas guys?