Power for an EQ5 SynScan ?

[knobby]

hi,

what sort of times are you getting with your various power tanks ?

I've got a very cheap and nasty (but safe) DIY job which uses 3 sets of 10 x 2500 mah nimh rechargeables in parrallel which should, in theory provide 12v at 1 amp for 7 hours or 2 amps for 3 1/2 hrs etc.

Gave it a dummy run last night (what else to do while its snowing) it managed 3 hours of tracking with 5 uses of the goto randomly slewing about a bit ( I now know what a meridian flip is )

The start voltage was 12.8 v and it was still slewing well but had dropped to 10.6 v so decided to call it a day and start the long winded process of charging 30 AA's.

How does that compare with the shop bought ones ?

Cheers for reading

[Photosbykev]

The EQ5 needs at least a 12v supply voltage if the supply drops below that you could get bad goto's and quirky behaviour and the current running through the motors becomes greater as the voltage drops. Even a small 12v 17Ahr battery will last 4-5 hours. If you get a bad cell in one of the packs you could also cause damage to the other packs so personally I would avoid going down this route

[knobby]

Cheers Kev, just had a large amount of AA's left over from powering Vivitar 283's a while back so buying 3 battery holders and a project box came to about £7 so it was worth a try

At the moment its all I've got so it will have to do for a while...

[knobby]

Got bored and left it tracking (in the extension) again, did a dummy set up, slewed a few times then left it running. Lasted just over 4 1/2 hours with no slewing, just tracking. I think I'll persevere with this until I save up for something better !

Cheers.

[Carbon Brush]

AA NiMH/Nicd are interesting.

In the past you couldn't anything above 500mAh, but now I have been offered up to 2700mAh.

Unfortunately the general observation has been that the larger capacity batteries degrade or fail more rapidly than the lower capacity.

I guess this is what comes of manufacturing in China for a penny less.

I used to have some NiCd that were from a camera flash. Made in 1971, still worked 20 years on. Now I see a significant failure rate after only a couple of years.

Given the low cost and known performance of lead acid, I stick with those for astro and other kit.

Leisure and large alarm batteries are cheap enough. Just make sure you limit the charge voltage to 13.8V though.