Is this normal??

Darkplague · #1 09-04-2007, 09:02 PM

Ok, So I'm not very happy with my battery supply at all. I have a 0.20 Amp computer fan running off the supply, and it only lasts 2-3 hours before it crawls to a halt.

I have 2 off 6V, 10Ah batteries hooked up in series, and this is all I can get out off them, a measly 2 hours with 1 computer fan

They have been recharged many times now, usually by leaving the recharger on for 2 days on trickle charge. When tested with a voltmeter they read 12.85 volts. Needless to say this is very frustrating!! Anyone offer any advice??

I have some heater straps on the way soon, but I doubt they'll be much use as the "whopping" 0.20Amp computer fan is sucking up all the juice available

Mark

Moonman (Michael) · #2 09-04-2007, 09:10 PM

Looks like something is up with those batteries. I run my fan off a 12v 7.2ah lead acid battery sometimes for up to 2 to 3 hours a time and when I recharge at the end of the night it only needs about 10 minutes for a top up so it barely scratches the surface.

Hope this helps

Mike

Darkplague · #3 09-04-2007, 09:14 PM

Quote:

Originally Posted by Moonman

Looks like something is up with those batteries. I run my fan off a 12v 7.2ah lead acid battery sometimes for up to 2 to 3 hours a time and when I recharge at the end of the night it only needs about 10 minutes for a top up so it barely scratches the surface.

Hope this helps

Mike

Thats not what I wanted to hear!! (since I have lost the receipt and its been over a few months now)

Moonman (Michael) · #4 09-04-2007, 09:20 PM

Given the degradation in such a short time reciept or no I reckon you'd be justified in trying to at least get an exchange from your supplier.

davewaldo · #5 09-04-2007, 09:21 PM

yeah... I also have a 12V 7ah battery and I have run my computer fan on my scope overnight and it was still going fine in the morning. Around 8hrs or so I guess.

It does sound like dud batteries. Sorry :-(

What sort of charger are you using?

SMR (Steve) · #6 09-04-2007, 09:40 PM

Quote:

Originally Posted by Darkplague

Anyone offer any advice??

One (or both) of your batteries is hosed.

BTW, series charging batteries is not a good idea. A problem with one battery can prevent the other batteries from getting fully charged (like losing one cell in your car battery).

You're better off with two 12V batteries in parallel, or switch to a 6V charger that lets you charge the two batteries in parallel.

Steve.

h0ughy (David) · #7 09-04-2007, 09:43 PM

I agree and it does sound like crook batteries. do the batteries act as a ballast/weight set for the scope? if so if you get a higher powered one, like a12 v 15AH from supercheap for 49.00 for a sealed lead acid then you would be set, for a long while and if you had 2 you could do a whole weekend, and keep the balance.

Darkplague · #8 09-04-2007, 11:55 PM

Quote:

Originally Posted by h0ughy

I agree and it does sound like crook batteries. do the batteries act as a ballast/weight set for the scope? if so if you get a higher powered one, like a12 v 15AH from supercheap for 49.00 for a sealed lead acid then you would be set, for a long while and if you had 2 you could do a whole weekend, and keep the balance.

Yes these batteries are basically all that fits in the space I had. There is no room in the rocker as the clearance is so small. To change to another size of ,batteries would be a nightmare, so I guess I will try to exchange them at least.

I am getting a consistent 12.85 Voltage from the Multimeter though when charged up. You would have thought that if one battery was crappy, this would never read as high as this??

aerobrake (Michael) · #9 10-04-2007, 01:18 AM

Mark,

Charge the batteries for the usual time required to get a full charge, then wait about 8 hours (measuring soon after a charge is misleading) and put the multimeter on them and see what readings you get. Measure the voltage in each cell if you can and post the result here when done.

Cheers
Mike

mill (Martin) · #10 10-04-2007, 06:58 AM

Measuring batteries with an multimeter has to be done with a load on the batteries or the multimeter will measure the open voltage.

acropolite (Phil) · #11 11-04-2007, 09:49 AM

Quote:

They have been recharged many times now, usually by leaving the recharger on for 2 days on trickle charge. When tested with a voltmeter they read 12.85 volts. Needless to say this is very frustrating!! Anyone offer any advice??

I'm with the others the batteries are simply worn out. FWIW SLA's are quite fussy about charging and discharging regimes see this link for more details

Darkplague · #12 11-04-2007, 07:57 PM

Thanks for all the advice everyone!

Yesterday I took them both back, along with the charger to the store and they will test them with the proper tools they have. It took me a bit of persuading, as I had bought them at least 4-5 months ago and didnt have my receipt but they agreed to look at them.

Will post the outcome when I find out what the problem was if anybodies interested.

Darkplague · #13 11-04-2007, 07:58 PM

Quote:

Originally Posted by mill

Measuring batteries with an multimeter has to be done with a load on the batteries or the multimeter will measure the open voltage.

That makes sense, however the store has the batteries now and are performing the appropriate testing to them.

Shawn · #14 11-04-2007, 08:24 PM

Steve said it a previous Post, If you have one lemon, the others will suffer in charging. and draw down. Charge each individually, and find the lemon. Do a drain test , a big draw item close to say half what the battery can supply, whilst measuring the maintained voltage, youll find the lemon real quick..

Unfotunately you cant stick a hydrometer in sealed cells...