Batteries

[sam_smith]

Martin, you should always aim to charge hawkers between each battle. The deeper they are discharged, the shorter they live.

[defyer]

Thanks that what I thought but just wanted to check

[Ianshock]

Would this be a suitable charger just to check these old SLAs Will and I have aquired !
http://www.argos.co.uk/static/Product/partNumber/7402137/c_1/2%7Ccategory_root%7CGarden%2C+DIY+and+leisure%7C95 54618/c_2/3%7Ccat_9554618%7CCar+equipment%7C9554675/c_3/4%7Ccat_9554675%7CCar+battery+chargers%7C9554688.h tm?Price+Cut=1http://www.argos.co.uk/static/Produc...ategory_root%7 CGarden%2C+DIY+and+leisure%7C9554618/c_2/3%7Ccat_9554618%7CCar+equipment%7C95546 75/c_3/4%7Ccat_9554675%7CCar+battery+chargers%7C9554688.h tm?Price+Cut=1

[leorcc]

Ian, That would do very well.

[Ianshock]

Thanks Leo...as the spec says Suitable for use with car batteries - 6 volts/12 volts/ sealed/ lead acid/ gel cell batteries between 20-120Ah - Charging rates 5.3 amps RMS would it be advisable to charge 17ah in parallel ? Read somewhere optimum C is 25% of capacity for SLAs

Our current batteries are old but we might buy some new SLAs so want to make sure we use the chargers properly from the start. At £20 each cant be a bad buy if there upto the job !

[leorcc]

I would only charge batts in parallel when they are new so they act as 1 battery. Old ones you might get more of a charge in one than in the other due to memory effects.

I wouldnt worry too much over the minimum Ah rating of the charger, its a pretty intelligent charger and it will slow down in time.

[terrorhurtz]

If they are Hawkers, then you really need to read the application manual:
http://www.commutercars.com/downloads/batteryCharging/HawkerGuide.pdfhttp://www.commutercars.com/download...awkerGuide.pdf

Hawkers are different from other lead-acid batteries. A lot of people do not realise their potential (and shorten their life) by not charging them correctly. In particular, you must charge them at 14.7 to 15V, no less.

I would NOT recommend using any lead-acid battery charger that does not specifically say it is designed for Hawker batteries.

Also, as it says in the manual - there are no restrictions on the current limit. One good way to charge them is just to use a big 12V power supply, like the 40A one that a lot of teams use -http://technobots.co.uk/acatalog/Online_Catalogue_Power_Supplies_29.htmlhttp://technobots.co.uk/acatalog/Onl...pplies_29.html -
set to 14.7 Volts and connect the battery/batteries directly to it and let them draw as much current as they want.

[blazerbotics]

We use to charge ours with a power supply, and took them off when the current dropped to about 1amp.

[woody]

Im NO expert on charging batteries but the charger I previously linked to on ebay ... new link provided here http://a1autowise.com/BatteryCharger.aspxhttp://a1autowise.com/BatteryCharger.aspx

Seems to meets the requirements stipulated by http://www.odysseybatteries.com/charging.htmhttp://www.odysseybatteries.com/charging.htm

(Message edited by woody on July 12, 200

[Ianshock]

Thanks all for your help. We tried the cheap option from argos and either the cells are duff or they are not upto the job...so they are going back ! One last question....the power supply linked from technobots....is this a variable current adjustable / limited one...do we need one (? / advisable) or just set the votage and go ! We aslo found another alternative...
http://stores.ebay.co.uk/TK-RADIO_POWER-SUPPLIES_W0QQcolZ2QQdirZQ2d1QQfsubZ9476935QQftidZ2 QQtZkmhttp://stores.ebay.co.uk/TK-RADIO_PO...d1QQfsubZ94769 35QQftidZ2QQtZkm
These prices for the lower amp ones look quite reasonable. Still undecided to but new SLAs or go NiMH ! If we go SLAs would even the cheaper non hawker SLAs be perfectly ok to charge like this ? (well need a couple of sets and £400+ is a lot of pocket money and bedroom tidying for Will !!)