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Small Battery + OpenPort = Dead Battery

4156 Views 31 Replies 12 Participants Last post by  yacoub
So I have been struggling with small batteries for a while now, I am on my second one in 18 months. The first one from AMS, which was a rebranded Odyssey, went out on me in only 9 months. I charged it out of the car and it would only last 3-4 days just sitting before the car would not turn over (without an OpenPort). I was working at the time so it wasn't uncommon for it to not show it's ugly face unless a holiday weekend or vacation came around. So I purchased a Battery Tender and ordered a new small battery.

I purchased a real Odyssey PC680-P and the car has been just fine for 5 months. I think it even sat at Evolution Dynamics for 12 days or so and cranked like a champ. I drive the car maybe once every few weeks or at autocrosses. I have not left the OpenPort plugged in for more than a day or so, actually since having this new battery I only plug it in at autocrosses to log my runs then remove it at home.

More than 3 times now, I have left the OpenPort plugged in while the car sat in the garage and more than 3 times now after 3-5 days the battery is COMPLETELY drained, so much so I have to remove the battery harnesses to get the battery to take a charge. I tried 2 times already leaving the car sitting in the garage for up to 14 days without cranking it and it has started just fine without the OpenPort plugged in. Needless to say, I am glad I figured it out but I really didn't think the OpenPort required enough current to drain the battery in just 4-5 days. I do realize it is additional load on the battery over what the ECU, alarm, etc. put on the battery.

So I guess the moral of the story is, if you are going to let your car sit for extended periods of time and you have a small battery kit, don't leave your OpenPort plugged in while you are away!
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lol wow. On a side note, you might want to check out the Shorai Li-ion batteries from Radix Motorsports. You can get more CCA and amh from one of their 3lb batteries than the odyssey. I run the 3.9lb one and have np leaving the car sitting for a week (though I don't leave my openport).

http://radixmotorsports.com/pdf/radix%20shorai%20spec%20full.pdf

http://www.baautox.com/forum/index.php?t=msg&th=9289&start=0&rid=749
lol wow. On a side note, you might want to check out the Shorai Li-ion batteries from Radix Motorsports. You can get more CCA and amh from one of their 3lb batteries than the odyssey. I run the 3.9lb one and have np leaving the car sitting for a week (though I don't use openport).

http://radixmotorsports.com/pdf/radix shorai spec full.pdf

http://www.baautox.com/forum/index.php?t=msg&th=9289&start=0&rid=749
WTF those insanely light!
I had the same problem on my SnapOn truck where I left a canbus breakout box connected to the OBD on board to demonstrate..... I don't think the box in itself drains much, but it was keeping some of the mini ecu's active on the truck by being plugged in.... So, that cool sales idea went out the window!
I had the same problem on my SnapOn truck where I left a canbus breakout box connected to the OBD on board to demonstrate..... I don't think the box in itself drains much, but it was keeping some of the mini ecu's active on the truck by being plugged in.... So, that cool sales idea went out the window!
That is what I am thinking, it is keeping something on the ECU alive, maybe not letting the ECU go to sleep.
Great minds eh!
Great minds eh!
All I know is, I probably tossed out a good battery not even thinking about the OBD device. I may have to hack open the OpenPort and put a toggle switch on the power line to keep it off when I want it off. I do know the device gets really hot also when being plugged in all day.
So I guess the moral of the story is, if you are going to let your car sit for extended periods of time and you have a small battery kit, don't leave your OpenPort plugged in while you are away!
That will also happen with a full-sized battery. Unplug the Tatrix cable OBD2 connector thingie as soon as you're done using it (unless the engine is running).

BTW - I have a PC-680 in a different car that I've had for about 6 years. I have unintentionally deep-cycled that thing at least three times - where it had less than 0.01 VDC after being disconnected from the load. After EVERY deep-cycle, I have re-charged it and it has come back to life. It still lives now 5+ years after the assorted deep-cyclings.

I disconnect it (pull negative cable) from the battery in the car when it's not being used - the car gets used less than 100 miles a year. And when I re-connect the PC-680 negative cable, the car starts right up without any charging.

These batteries are GREAT!!
That will also happen with a full-sized battery. Unplug the Tatrix cable OBD2 connector thingie as soon as you're done using it (unless the engine is running).

BTW - I have a PC-680 in a different car that I've had for about 6 years. I have unintentionally deep-cycled that thing at least three times - where it had less than 0.01 VDC after being disconnected from the load. After EVERY deep-cycle, I have re-charged it and it has come back to life. It still lives now 5+ years after the assorted deep-cyclings.

I disconnect it (pull negative cable) from the battery in the car when it's not being used - the car gets used less than 100 miles a year. And when I re-connect the PC-680 negative cable, the car starts right up without any charging.

These batteries are GREAT!!
That is good to know! I just didn't realize it when I drove the car daily...it wasn't until I only drove it every week or so that I notice the issue.
lol wow. On a side note, you might want to check out the Shorai Li-ion batteries from Radix Motorsports. You can get more CCA and amh from one of their 3lb batteries than the odyssey. I run the 3.9lb one and have np leaving the car sitting for a week (though I don't leave my openport).

http://radixmotorsports.com/pdf/radix shorai spec full.pdf

http://www.baautox.com/forum/index.php?t=msg&th=9289&start=0&rid=749
Sweet ! Will definitely be picking up one of these. Which one do you run?
LFX24A3-BS12?
Or
LFX24L3-BS12?
Small corectino: That is NOT a Li-Ion battery.

It is a Lithium-Iron-Phosphate composition.
Ah, good catch Yxd68.

I run the LFX24A3-BS12.
Ah, good catch Yxd68.

I run the LFX24A3-BS12.
Did you have to make a custom bracket or do any fab work? Or are you just using the foam spacers in the OEM tray to make it fit?
I have a custom tray that my buddy made me from aluminum when I had a motorcycle battery in it. I'll post a pic tomorrow, but you'll see I also had to take some creative license :p

You can use any mini battery style setup though. I'd lay the battery down sideways and just run a bar across it like a normal battery setup. Normally the metal side bars don't have enough thread to go down far enough, but you can just rethread those with a tap&die set.
What do you guys recommend for a battery minder/tender?

Do you connect it under the hood or to the battery in the trunk?

Thanks.
What do you guys recommend for a battery minder/tender?

Do you connect it under the hood or to the battery in the trunk?

Thanks.
I have a http:// http://batterytender.com/automotive/battery-tender-plus-12v-at-1-25a.htmlDeltran Battery Tender 12V Plus and love it. This was the first time I didn't use it and look what happened! I was to worried about going on my vacation I forgot to plug it in.
Hmmm. I always just take the openport out when I'm not using it. I don't leave it plugged in when just putting around town >.>.
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