high voltage alarm?

[rocwandrer]

What's your favorite adjustable-voltage, cell-level alarm that also does high voltage alarm (so I can protect my packs when on a bulk charger as well as when discharging)? Any that will do two step low voltage alarms, or anything cool like that that aren't junk?

Richard

 

[circuit]

It's called BMS.

 

[dogman dan]

Only thing I know of is the cellog 8's barely audible beeps if a cell goes over 4.2v. Not sure if they can be adjusted.

Surely other similar monitors have over volt warning too.

 

[rocwandrer]

It's called BMS.

That's just time and money. The reason I'm avoiding it surprisingly enough.

 

[rocwandrer]

Only thing I know of is the cellog 8's barely audible beeps if a cell goes over 4.2v. Not sure if they can be adjusted.

Surely other similar monitors have over volt warning too.

Missed this post somehow. Thanks. I think the cellog 8 beeps being barely audible would be a plus for me. The chinese ebay knockoffs I have are so loud you can hear them echo off of houses and stuff I've noticed product descriptions for this stuff is pretty lacking in content/truth (some stuff has cool features not advertised, some stuff has cool features advertised that isn't on the product). I was hoping someone could chime in with a "i have ___ and it does that, but sucks because _____" (I figure there is something wrong with all of this stuff, but some of it I can live with.)

 

[Ykick]

CellLog8's polite alarm's saved me overcharge a few times here. I was short a charger in CA for a while so I was using a rigged setup with off timer in the fireplace. At one point I asked the wife, "what's that beeping?" She replied that it was the fireplace.... Oh yeah, 'had forgot all about 'em.

 

[wineboyrider]

There's a thread in here somewhere about using a smoke detector modification to the output capability of a cell log....

 

[heathyoung]

Use a cell-log and a relay to drop off the charge if a cell goes over - easy.

 

[rocwandrer]

Use a cell-log and a relay to drop off the charge if a cell goes over - easy.

So the high voltage alarm is adjustable to 3.65v on the cellog 8?

 

[ambroseliao]

Celllogs also have an alarm output so you can rig up a much louder alarm if needed.

http://epbuddy.com/userdownload/CellLog_8M.pdf

 

[heathyoung]

Yep fully adjustable LVC and HVC that will do LiPo or LiFePO4.

Alarm output can also be used to drive a relay - you can get a 24V relay with NC terminals and put these (driven by the cell-log's output) in series with the strings to disconnect them. Bear in mind high voltage strings may exceed the relay's capabilities. Safer than a beeping alarm and actually does something useful

 

[rocwandrer]

Celllogs also have an alarm output so you can rig up a much louder alarm if needed.

http://epbuddy.com/userdownload/CellLog_8M.pdf

That manual, terrible as it may be, was very helpful. Thanks! Looks like it can be set to high and low voltage alarm as well as cell voltage disparity alarm with wide, custom adjustable set points.

 

[rocwandrer]

Yep fully adjustable LVC and HVC that will do LiPo or LiFePO4.

Alarm output can also be used to drive a relay - you can get a 24V relay with NC terminals and put these (driven by the cell-log's output) in series with the strings to disconnect them. Bear in mind high voltage strings may exceed the relay's capabilities. Safer than a beeping alarm and actually does something useful

I like this idea.

 

[wineboyrider]

Is there a link for the 24v relay you speak of?

 

[heathyoung]

Well, one of these http://www.jaycar.com.au/productView.asp?ID=SY4047 would do the job nicely.

If you needed the full 30A charge current, you would have to use it with the transistor of the cell-log in normally closed mode (since the NO contacts of the relay are rated for 30A, and NC are rated for 20A).

 

[bowlofsalad]

Well, one of these http://www.jaycar.com.au/productView.asp?ID=SY4047 would do the job nicely.

If you needed the full 30A charge current, you would have to use it with the transistor of the cell-log in normally closed mode (since the NO contacts of the relay are rated for 30A, and NC are rated for 20A).

This seems extremely useful, thanks for sharing. However, I would have no idea how to implement such a thing as a total newbie. But, this does sound a lot like a cheap secondary or even primary BMS option.