Any sparks help?. Which AH capacity ?

[marconi]

For any sparks out there.
I have an outside disability scooter store, the opening and closing of which
is operated by a 24Volt lift arm running off SLA batteries (2x12v,7.2AH in series).
After 12 years one of these batts is knackered so I will renew both.
Locally, I can get the same sized batteries but only 6.0 AH, not 7.2 AH.
Obviously, they will give me the same 24V but will they have enough guts
for the job? The store in only opened a max of twice a week and the batts are left on charge 24/7.
Hoping someone can advise. Thanks.

[gblades]

The capacity is just that, how much charge they can store. The amount of current they can supply will vary on their physical size and construction.
However typically they can generate huge currents (enough to melt a spanner if you drop it across the terminals) so the smaller capacity batteries should be fine.

[Spark123]

Mail order?

[TicklyT]

'Sealed' batteries can be fussy about their charging requirements, so check your charger output is suitable for the batteries you choose.

__________________
If it isn't broken, keep fixing it until it is

[marconi]

Thanks, gblades. the 6.0 AH batts are the same physical dimensions as the old 7.2 AH batts. Just wondered if the liftarm actuator would draw too much current and cause premature batt failure but I doubt that. SLAs are
quite robust and they will be used infrequently between charges.

spark123, Mail order? What? please explain.

[Spark123]

I mean can't you get the correct ones mail order, for example from here:
http://cpc.farnell.com/camden-electronics/bel120072/battery-europa-lead-acid-12v-7/dp/BT02673
(CPC have an offer on at the mo, if your web order is £20+VAT then the P&P is free - don't forget to enter the code in when you checkout)
or any other online retailer?

[aptsys]

12V 7.2Ah batteries are standard alarm panel batteries. I'm pretty sure even Maplin stock them.

[Lectrician]

Or any electrical wholesaler, of which, most towns will have a few.

[electronicsuk]

Agree that 6Ah replacements should be fine, but of out of interest, why the need for batteries if they are kept on charge 24/7 from a mains supply?

__________________
Matthew

"I told you, I only wrote that poem to test my printer!"

[marconi]

Thanks all.

Aptsys, you're right! Maplins price: 2X 12V 7.2AH is £60
Electical wholesaler: 2X 12V 6.0 AH is £25
The Physical sizes are idendical. Hence my question. Just wondered
if the 6.0AH batts would be good enough, saving £35.

Lectrician, see above re wholesaler.

I don't know if you guys are employed or running businesses in
electrics. I am a retired 70yrs old on very low income, so that
difference in cost of £35 is important to me and cannot be reclaimed.

Again, thanks for response.

[marconi]

electronicsuk,

The Lift/Close activator has to be low voltage to comply with regs,
in this case 24V. DC. Up/Down is determined by polarity via the respective external buttons.
Heavy current is drawn to lift or close the metal store lid and attached front, so a simple stepdown transformer and rectification would not be appropriate, hence the battery option.
This installation is outside the house, supplied via armoured cable from
an RCD spur inside.

[aptsys]

http://www.securitywarehouse.co.uk/catalog/index.php?main_page=product_info&cPath=36_46&products_id=113

http://www.alertelectrical.com/Burglar-Intruder-Alarm-Systems/Burglar-Alarm-Batteries/70ah-12v-Back-Up-Battery-For-Burglar-Alarm-Control-Panels-AB7.asp

[marconi]

Thanks for your time aptsys.
A new search this morning has found the 7Ah batts
for half the Maplins price @ Newey & Eyre local branch
so I am well pleased and can now close this thread.
Thanks to all.