After some details of SLA weights and stuff

[daveimi]

I'm looking for some weight details of SLA batteries. My drivetrain is 24V so I'm looking to make up the voltage with a pair of SLA's at 12 V each. Does anyone have any big SLA's of this voltage they could give me a rough weight on?

I've read somewhere that there's a minimum weight for heavies which I'm struggling with a bit, so filling it full of batteries should help haha. Also, if anyone knows the weight I'd appreciate details on that too lol.

[mattsdragons]

I think 2 hawkers are around 10kg the pair. You are better to run a paid of 12v batteries to give the 24v. If you are looking to add weight just add tons of packs, a bot with 4 SLA's (2 for each motor) would run for a pretty long time

[daveimi]

That's awesome thanks. Do you know if they're literally sealed for life, if I need to fill them up with water, if I'm still allowed to use these batteries and where I can get a charger from them? Have had the mad idea of using a car battery charger to charge them?

I've had half a heavy built for 12 months but couldn't work out how to mount half of it and now it's clicked, so am frantically get finished for the Northern Tour later in the year lol.

[mattsdragons]

That's what I used before and worked fine. They are sealed units with acid (Hence the name lead ACID battery)

There is no rules that they you can't use them, not commonly used now as they are quite old tech and not the most efficient in power delivery but still make a HW run

[craig_colliass]

Hi

5.72Kg each I just weighed one, so 11.44Kg. I have only just stopped using SLA batteries in my robots. They proved reliable and cheep, I used an ordinary car battery charger to recharge at shows for years they worked fine. these are the 16Ah type.

[daveimi]

That's great thank you! Will go and have a look at what maplin have on the way home tonight

[harry hills]

Don't bother with maplins. Get them off the internet. Look at component shop or something.

[daveimi]

Just had a look at component shop and they do 20Ahr 12V batteries and £10 chargers! Gonna get some of them ordered when I get home! Can you lie batteries on their side in the robot, I presume you can?

Does any one know the minimum weight for a heavy? Is it 60kg?

[maddox10]

Woha, some pointers.

Do you know if they're literally sealed for life, if I need to fill them up with water

For the robots we need Sealed Lead Acid batteries, but not with liquid filling. Gelcells (were the acid is an very thick ooze) or AGM Cells (glassmatt fiber as retainer for the acid) are mandatory, since the start of Robot Wars.



7.8
The following battery types can be used without any specific precautions although care must be taken when
any battery particularly during charging:
 Pb (Sealed Lead Acid, SLA), non-spillable gel type. (e.g. Yuasa, Hawker)

Imagine a liquid acid battery springing a leak during a fight. I don't want to clean up that mess.

Weight of SLA batteries. A 7 to 9 ah SLA battery (PBQ was our favorite brand, cheap and dependable) weights around 2.8 kg.
Hawkers come in so many flavers it's difficult to give a weight, but the cheaper genesis (rebranded Yuasha) sets are about the same. The High End pure lead technologies are a tad lighter for watts stored. But the pricetag gets high fast.

Weight of a heavyweight
2.1 Weight classification
Heavyweight: 55kgs to 100kgs [220lbs]

[daveimi]

Ok Mario that's great. So to sum up, batteries must be gel cell to prevent leaks and general all round catastrophe, and I'm ok as long as I can be 55kg - 60kg + :-)