Battery charger question for the electrically challenged

[blueflyer]

Odyssey says their battery charger will not keep my odyssey battery charged during ground avionics usage.

So, from reading the archives I understand that I don't want to use a cheapo battery charger because once the battery is fully charged the charger will sometimes supply a spike of amps to the battery.

Also read where el cheapo battery chargers supply "dirty" DC and the avionics like "clean" voltage....and I see that the airplane battery can act as a buffer to keep the volts steady during ground power operations.

So, I checked several battery charger spec sheets on the net, but I don't see where they talk about the potential amps supplied once a battery is fully charged.

Long story short is that I'm still confused. So, Here's my questions:

1) When folks are running their high $$$ avionics on the ground for testing/software, etc, what charger are you connecting to your battery in order to keep your battery from getting drained?

2) or, how do you test your avionics without draining the battery?

I see where the Stanley unit goes into float charge once the battery is fully charged and some knucklehead on youtube claims to have tested the battery once it was fully charged and there were no spikes. Knucklehead said a steady 300-500mah once in float mode. Sounds like a good product if our knucklehead is correct, right?

[cfiidon]

I have been testing my avionics solely on the battery, then recharging with the Odyssey.

I have also kept the Odyssey on charge while running the avionics. Can't tell you if it kept it fully charged or not while doing so, but it was certainly enough for the task.

Just test with the Odyssey connected, then leave it on for a full top off charge.

Don

[Brantel]

If you are going to use the Odyssey brand charger, I suggest that you let the battery run down a bit before turning it on.

If you turn it on and it goes to trickle pretty quickly, your battery will not get fully charged and it will cause it to fail prematurely from sulfidation which is caused by storing the battery in a less than fully charged state.

I learned this after killing two batteries before their time!

[blueflyer]

Originally Posted by Brantel

If you are going to use the Odyssey brand charger, I suggest that you let the battery run down a bit before turning it on.

If you turn it on and it goes to trickle pretty quickly, your battery will not get fully charged and it will cause it to fail prematurely from sulfidation which is caused by storing the battery in a less than fully charged state.

I learned this after killing two batteries before their time!

Good idea. I think I have caused my to fail prematurely also. I feel more comfortable sticking with the Odyssey charger. Thanks.

[Walt]

You should not run your avionics on a battery charger, just leave the charger off until you're done playing around then charge the battery back up.

[blueflyer]

Originally Posted by Walt

You should not run your avionics on a battery charger, just leave the charger off until you're done playing around then charge the battery back up.

I guess I should clarify that the length of time that I have my avionics on and running is such that it will discharge the battery down to a voltage unable to turn a prop blade on start.

With that information, should I still just run off battery power and then recharge it or supplement the battery power during ground avionics usage in some way?

Sorry for the many questions. I just wrestle with understanding electrical stuff.

[rocketbob]

Chargers are not good devices to power your avionics with because they are designed to be constant-current, rather than constant-voltage.

Want a cheap way to power everything in your airplane on the ground? Look on ebay for old server power supplies, particularly this one: HP-194989

They put out 30+ amps at 12V!

Follow the instructions here to mod one: http://ohiopacket.org/files/docs/Powersup.pdf

I actually go a bit further and mount a toggle switch to them.

At work we trashed a dozen or so old servers so I got a bunch of these for free. I had several puzzled looks as I had a cart top full of these headed to my car.

[Walt]

First would be to turn off as many things as possible (load shed) while testing. As long as the voltage doesn't drop under 11.5v you should be ok, most avionics will start to drop out around 11v. Use a jumper battery if you need more time than the ships battery will provide or do like Bob suggests, invest in a power supply.

[blueflyer]

ok, thanks to both. I just picked one of those up on Ebay, so those instructions are greatly appreciated. Thanks again.