Car batteries

Hi all

Little of track here...

Im currently building a remote control lawnmower, not a battlebot, though using much of the same tech, bosch 750s) etc.

Since there will be little roughing and no tilting to speak of, how would using car batteries work; can they stand the discharge needed ( prolonged tapping of fairly high rate but few high amp surges) ?

Looking into car batteries since these are fairly cheap + can hold a lot of ahs + dont have much weight and size restriction in my application.

regards

Car batteries would be fine, as long as you can fit the weight/size within your design. What kind of size are you thinking of building to? Around the size of a push-along lawn mower or a large ride on mower?

Regards, Ewan
http://www.micro-maul.co.ukhttp://www.micro-maul.co.uk

Thanks for the response, the lawn mower will be little bigger than a push along, a lot heavier, have a powered reel in front and use tank style steering...when it finally gets done someday.

Mostly for fun though, cant really envision cutting the lawn week after week by RC but had a spare bosch 750 from a dead batteri LM and needed a project..

regards

hehe, I know how you feel :proud:

Car batteries are not very good for full discharge use.
Used like this they will die after about 60 complete charge-discharge cycles.

Batteries that are designed for traction use, like the ones we use for robots and golf buggies, will last for up to 2000 charge-discharge cycles.
Even the cheaper ones will last 200 cycles, which makes them cheaper than car batteries if used more than 60 times.

Car batteries are good for one thing only, starting cars which uses a lot of current and normally only about 5% of their discharge capacity.

Damn, had a feeling there was a catch. Know any other price effective (cheap) solution with same kind of amp hours (50-60ah)...?

regards

Leisure batteries like the ones mentioned by Roger are not too bad price wise, and they are designed for deep discharge...ie running flat between charges It may be worth ringing around some local caravan/camping shops.Here is one link I found http://www.countybattery.co.uk/cgi-bin/linkcat.cgi?name=Leisure~and~Camping~Batteries.... nothttp://www.countybattery.co.uk/cgi-b...d~Camping~Batt eries....not as good as a Hawker no doubt but for the use you have in mind more than ample I would think. I am sure with some more searching even better deals are available

Tom

Tom

OOPS Mistake on the URL ...it still works though, just scroll down to the Leisure battery section

Tom

http://www.telford-electronics.com/hawker_batteries.htmhttp://www.telford-electronics.com/hawker_batteries.htm

I have some 17Ah slas going cheap, you could try a pair in parallel for capacity.

Beware using leisure or standby lighting batteries. They are normally designed to give a low current for about 20 hours and do not like heavy current. Only traction batteries are suitable for giving heavy currents for short periods.
Golf buggy or mobility buggy batteries are ideal as well as the specialised Hawker batteries that are the roboteers favorite.

I stand corrected.

Tom

You want Optima Yellow Top batteries!

You can run them fairly flat, and they will deliver high currents for sustained periods and in excess of 700A peak without damage. I use them for winching (on Land Rover) and they out-perform almost everything. They are a good hybrid of a leisure and a high current battery. Mine are now 5 years old and showing no signs of deterioration.

5 years is a good innings for any car battery, never mind one subject to repeated abuse!

Down side - £150 each! - worth every penny though.

Si

Thanks all, great input. While not bying batteries just yet (couple of months probably), now Ill be able to size the chassis to the batteries mentioned. :)

Samuel, thanks for your offer but Im looking for 60 to 100 ah at 24v and for that I would need to many 17ahs to be practical Im afraid.

regards

The company I work for sell batteries that might work for your application Thomas, only 33Ah though

http://www.jprelec.co.uk/index.htm?http&&&www.jprelec.co.uk/docs/order_code.asp?pCode=%5F0R511T9PV&PGID=%5F0QN0SHQK S&LEVEL=1&SearchType2=6&MODE=&PARTNO=&KEYWORD=&PG= Batteries&RELATED=0&rtype=A&OC=NONE&TEMP=NONEhttp://www.jprelec.co.uk/index.htm?h...rder_code.asp? pCode=%5F0R511T9PV&PGID=%5F0QN0SHQKS&LEVEL=1&Searc hType2=6&MODE=&PARTNO=&KEYWORD =&PG=Batteries&RELATED=0&rtype=A&OC=NONE&TEMP=NO NE

i have got 4 Hawkers 12v 16 amp hour with 2 chargers in the for sale section you can have all 4 and the two chargers for £140.00 they hacve only been used a few times