Why is Current Output on my charger adjustable please?

[Vanilla]

I'm very dim about electrics, electronics, plumbing etc (not good if you own a boat!) so very grateful if somebody could please tell me in very simple language what the top right hand dial on right of picture (labelled "Current Output") is actually for on my Mastervolt charger? Why would anyone wish to alter current output?

 

[Lon nan Gruagach]

Its possible to harm a lead acid battery by charging it too fast, the dial will be a max current limit.
without manufacturer's info for a specific battery then take the Ah rating, divide it by 10 and use that as a max charge current.

 

[Vanilla]

Thanks for the reply. Still a bit puzzled as the dial does not have any numerical marking to set it to the magical "24" based on your sum..

 

[sailorman]

wont the charge rate be displayed in the top l/h read-out

 

[VicS]

Still a bit puzzled as the dial does not have any numerical marking

Can you not find an instruction manual for the charger on line? Mastervolt seem to have loadsa stuff available

 

[Vanilla]

Sadly Vic I have the manual but don't understand it.....��.....I've just left the dial as it was for 7 yrs but was wondering if turning it up would do something specially good....!!! Remember Spinal Tap and the amp which went up to 11...lol. Anyway I'll leave it alone as batteries seem to be fine. Thanks for your help as always.

 

[William_H]

I imagine that when charging a fairly flat battery you would observe the actual current going into the battery on the amp meter. Then if this is too much (over the magical 10%of AH) then adjusting this control will reduce the current. It will actual be a limiting current figure so that charged is normal up to that point. ie a safety feaure. good luck olewill

 

[sailinglegend420]

For someone who says they are very dim about electrics this is very sensible question. Batteries limit the amount of current that they want themselves but manufacturers "recommend" a maximum for longer battery life. Trojan say 10-13% of the battery Ah capacity others say a maximum of 20%. Lifeline AGMs say a MINIMUM of 20%, so you need to buy a charger of the correct size or be able to adjust its output. My 120 amp Victron charger has a software adjustment that controls the maximum output.

See this current thread for more discussions:

http://www.ybw.com/forums/showthread.php?426825-numpty-battery-charger-question&highlight=

 

[VicS]

Sadly Vic I have the manual but don't understand it.....��.....I've just left the dial as it was for 7 yrs but was wondering if turning it up would do something specially good....!!! Remember Spinal Tap and the amp which went up to 11...lol. Anyway I'll leave it alone as batteries seem to be fine. Thanks for your help as always.

If you told us the model description of the battery charger maybe it would be possible to find the manual on line then perhaps someone would be able to read and understand it and advise you accordingly.

My own ( garage, not boat) battery charger has a selectable maximum current setting. The instructions advise what setting to use vs battery capacity. It alters the control parameters, as well as just the maximum current, to suit the different battery capacities.

If you set your control so that the maximum charging current into a significantly discharged battery is never more than 10% (upto 15% perhaps) of the battery capacity you wont be far wrong.