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JonteJsson
06-15-2005, 09:49 AM
I got a Graupner lipo charger but I have some questions.
First of all the charger says that it auto-detects the cell count and charge it with 1-2C shouldn't you just charge it at 1c?
This is a pic of the manual:
http://halfeight.com/gallery/data/500/graupner-charger-manual.JPG
It also says that it charge in phases, it starts with a low current to analyse the battery, then it raises the current and in the end it lowers it again..
Shouldn't lipo cells be charged at a constant current?
Just want to know before I ruin be new pack : (

Eurylokhos
06-15-2005, 02:22 PM
Lipos should ONLY be charged at 1c, I'm not sure where they got the 1-2c from in that manual, but if you check with the manufacturer, I have yet to see one that says to go above 1c. And on the charging, most higher end chargers charge like that. It's supposed to be the best way to do it.

Also, be careful with the Lipos, they can be extremely dangerous, I've been using them in planes and helis for about a year now, and they get charged and stored in a fireproof safe. Also, if they get ANY physical damage from a crash, or being dropped, do yourself a favor and leave it outside in a place where it won't do damage if it explodes for at least a few hours to make sure that it is safe. Better to have it go off outside than in your house.

TNB
06-15-2005, 04:31 PM
Are you using a fireproof safe to charge batteries or something like a simple lock box? If you would, please provide photos of the fireproof safe and the wiring set up for the charger and batteries since I'm assuming the charger remains on the outside of the safe while it is plugged in so the wires must go through the safe some how. I've also seen videos showing the use of a simple fire proof bag which appears to work. I've also seen "lock boxes" but supposedly the lids or tops have been blown off. Apparently, some people are now "venting" the lock boxes with a tube. Then there are kilin pots. Myself, I'm using a cast iron kettle with a small bag of sand placed inside on top of the LiPo. Supposedly, if the Lipo blows, the sand will smoother the lipo.

By the way, I've also read instructions to charge the lipos based on the cell count and mAH. As the other member wrote above, 1500 mAH would be 1.5. Another example would be that a 1900mAH would be charged at 1.9. Of course, like any other batteries, the mAH is getting higher and higher and some have detection devices; and the chargers are getting better and better. And overall, I've read numerous times that batteries be charged at .5; however, who wants an overnight charger and charge.

JonteJsson
06-15-2005, 04:38 PM
Hi.
I just called the hobbyshop where I bought it.
They said that it is not charging over 1C despite of the manual.
I am charging it in my BBQ outside..

TNB
06-15-2005, 04:56 PM
"C" appears to be "cell capacity" and 1C, the recommended charge rate which is 90% capacity in one hour. This article at FMA also mentions not to exceed 2C and not to charge in excess of 4.2v per cell. Consequently, when I charge 1900mAH lipos at 1.9A, it is still charging at 1C.

http://64.233.187.104/search?q=cache:__SqZRyPE7gJ:https://www.fmadirect.com/support_docs/item_1143.pdf+%22charging+lipo%22+1C&hl=en

https://www.fmadirect.com/site/home.htm

Eurylokhos,
Looking forward to the photos.

Eurylokhos
06-16-2005, 01:57 AM
I'm using a amall firesafe to charge, and another to store them in. It's a Sentry, like you can buy at Walmart. they aren't airtight, infact there are small holes at the bottom. I've actually had a Thunderpower 3s 1320 go nuclear on me while charging in my house, in the Sentry firesafe, and if it weren't for the smell, and my Triton charger beeping with an error, I wouldn't have known that it had happened until I opened the box. I always stay with them when charging, but even so, it's nice to have the protection. I grabbed the handle and ran it outside and let it sit a while before opening it up, and it was a mess in there. I could have lost my house (some people have who don't use the same precautions.)

I don't have any pics handy, but I just have a long charge lead that has relatively thin wires that I put in it, and lock the lid down. Like I said, it's not airtight, so it won't explode, but it'll control the fire.

TNB
06-16-2005, 04:21 PM
Thanks for the information. I do have a small fire proof safe but it is very heavy and holes would probably have to be drilled into it somehow for wiring since it doesn't have any holes any where. Instead of a long charge lead, the custom boxes I have seen use the red and black wire connectors like on the back of stereo equipment, so the batteries can hook up on the inside and the charger on the outside.

halfEIGHT
06-18-2005, 01:25 AM
So, what are you guys using when at the track!? :confused:

TNB
06-21-2005, 03:41 AM
I take a small cast iron kettle and a bag of sand. I just leave the lipos in the kettle and put the bag of sand on top of them. The idea is that if the lipos explode, the cast iron kettle will keep the "explosion" contained and the sand will smother out any flame or fire. I've also seen the smaller Sentry safes here at the hardware store for just under $20.00. Perhaps, I'll pick one up and see if I can wire it though I didn't notice any holes in the bottom; however, I wouldn't suprised if the lock would be blown open if a lipo did explode so I'd probably still use a bag of sand.

akura2
06-21-2005, 03:44 AM
um... explosions?


I think I'll stick with NiMh and leave the LiPos and my Triton for my planes

TNB
06-21-2005, 03:51 AM
I take it you don't plan to convert a Miss Bud into an electric floating, flying, and surface car?

http://www.michaelconnally.com

By the way, I didn't own a lipo charger until I started running them in R/C cars--Now I own three though I only use the Thunder Power and the Triton.

akura2
06-21-2005, 05:47 PM
that was amazing!!.... hmmm I might have to get one of those.....


OUCH!... my wallet