Fat Boy – September 09 Archive

23rd September 2009

Little tip… don’t use a 12v bulb for your load. The battery will be at 16v when it switches to discharge mode and that voltage instantly blows the bulb.

13th September 2009

There are mail strikes in the UK at the moment so still waiting for my new meter. Until then, here is a better picture of Fat Boy’s circuit.

Fat Boy Circuit

9th September 2009

More set backs… my USB multimeter has packed in so I’ve ordered a new one… It will hopefully be here this week and then I can begin cycling the batteries.

4th September 2009

The OCD Module looks like it is working fine. Here is the graph of the test showing the battery voltage over time.

OCD Module Graph

The load is a bit too heavy which is why the batter voltage is dropping over time. For the conditioning process with the OCD, the load needs to be relatively light compared to the input power since ideally we want the battery to reach around 16 volts before we begin discharging, though once the battery goes over 13.5 volts pretty much none of the energy we are putting into the battery adds to the battery’s charge.

So in this case, I either need to use a lighter load, or turn up the power on the oscillator. At the moment it is running on 850ma, and the load is also 850ma so all things considered it’s COP seems pretty good at the moment. I’ll take the input power to over an amp and see if it gets the battery to a high enough charge before discharge.

3rd September 2009

3rd September 2009

The oscillator is running perfectly. Here is a scope shot across the emitter and collector of one of the transistors.

Solid State Scope Shot

I have now set it up with the OCD Module and have set it for short cycles to test its reliability… It is hooked up to a usb multimeter to record the battery voltage every 60 seconds.

Once I’m satisfied the OCD Module is working well, then I will set it for longer cycles of around 16 hours charge then 16 hours discharge.

2nd September 2009

Just finished the new circuit. The coil is 80 turns and is pretty close to the Brooks Coil configuration so it will have maximum inductance and the lowest resistance.

I originally had a 0.5 farad cap pulser hooked up to it to investigate reports that the batteries continue to charge after being disconnected after being charged with this method. Unfortunately I didn’t see these effects, though my batteries aren’t conditioned yet so that may be a factor. I took out the cap pulser in the final design more for safety than anything else. It was only rated at 20v so if the relay failed for any reason the cap would soon explode. Since I am going to be leaving this running for long periods of time unattended (not recommended by the wserver pop.1and1.co.uk can not be founday… do so at your own risk) I didn’t want the added risk of the cap exploding.

To give you an idea of what could happen, this video shows a capacitor that is around 50,000 times smaller than the one I was using!

I’m still testing the new circuit at the moment but it appears to perform well. When I am sure it is operating properly, then I will hook it up to the OCD Circuit and begin cycling my batteries.

Watch this space!


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