Power supply question

Darkplague · #1 01-10-2006, 02:26 PM

Can anyone tell me if it is safe to lay a 12v 18A Rechargeable battery on its largest face in the bottom of the rocker box??

I dont have the room to stand it up, so I will need to lay it down. The battery is supposedly fully sealed but I'm not sure if youre supposed to use them laying down.

RB (Andrew) · #2 01-10-2006, 03:14 PM

I don't think it's a good idea Mark.

Starkler (Geoff) · #3 01-10-2006, 03:34 PM

An 18ah is a big battery for a truss dob. Do you really need one that big?

mojo (Terry) · #4 01-10-2006, 03:38 PM

If it's a sealed Gel Cell then yes.

h0ughy (David) · #5 01-10-2006, 03:46 PM

never ever lay a battery down like that. they are sealed so that if they tip they wont spill within a short time, however after a while they leak like a sieve, as there are holes to help the system breathe

mojo (Terry) · #6 01-10-2006, 04:39 PM

Quote:

Originally Posted by h0ughy

never ever lay a battery down like that. they are sealed so that if they tip they wont spill within a short time, however after a while they leak like a sieve, as there are holes to help the system breathe

Sealed Lead Acid batteries can be installed in any orientation. They do not vent unless under extreme conditions. ie. over-charging. If they do vent, they are most likely damaged.

h0ughy (David) · #7 01-10-2006, 04:42 PM

Quote:

Originally Posted by mojo

Sealed Lead Acid batteries can be installed in any orientation. They do not vent unless under extreme conditions. ie. over-charging. If they do vent, they are most likely damaged.

no argument

just follow the manufacturers recommendations

RB (Andrew) · #8 01-10-2006, 04:53 PM

I've never seen one oriented any other way except the 'right' way up.
They're not even stored any other way in stores that sell them.

But just to be on the safe side why risk it for the sake of your rocker box!

bloodhound31 · #9 01-10-2006, 05:59 PM

I'm not sure about the internal construction of a sealed lead acid battery, but if its anything like a normal lead acid car battery for example, then they are made so that the acid in them is supposed to completely cover the lead elements inside for production and storage of electricity through chemical reaction and conductive plates in each cell. If you tip them over then it follows that all or part of a plate or plates would then be exposed above the acid line. Hence lowered efficiency of the battery and the possibility of a cell, "dropping out".

I wouldn't risk tipping it over unless you contact the manufacturer direct for advice.

P.S. Also, a lesson learned through experience, don't charge the battery too long or you will stuff it! Ive lost two sealed units like that when i left them on charge for a week.

Darkplague · #10 01-10-2006, 06:15 PM

Thanks for everyones input. The general consensus seems that it is not a good idea then.

I am trying to find a rechargeable battery that will fit inside the cavity of my rocker box which has 3" of height.

I want to power the following with it:

Mirror cooling fan
Secondary dew heater
Eyepiece dew heater
Finder dew heater

And also perhaps my Argo Navis.

Can anyone suggest any particular battery that would fit in this 3" space??

middy · #11 02-10-2006, 01:11 PM

Here is a good read on SLA batteries:

http://www.jaycar.com.au/images_uploaded/slabatts.pdf

It says in the article that they can be used in just about any position.

Merlin66 (Ken) · #12 02-10-2006, 05:29 PM

I use Gel cell batteries at work (Exide) up to 85Ahr capacity, and they are safely rated to work upside down.
Re charging SLA and Gel batteries.... you need to invest in a two stage "smart" electronic charger. These charge at maximum current up to 80% of the battery capacity an then drop to a lower charge rate until the battery is 100%... you can leave them on indefinately without damage to the battery.
The old K-mart 4amp special will NOT cut it with the new SLA or Gel batteries.