INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

finding the right charger for 12 volt lithium ion batteries

finding the right charger for 12 volt lithium ion batteries

(OP)
Hi

Let me first admit that I am total novice working on a pet project, so please give advice with this in mind.

Here's what I'm working with:

I'm looking at ordering 5 of these batteries, so I can wire each up to an emergency beacon light and have them be portable.
http://www.alibaba.com/product-gs/666667818/Rechar...

Here is a link to the exact beacon light model which I have 5 of:
http://www.fedsig.com/products/83/model_100

First-
Is it a good idea to use this kind of battery to power this light (and motor which spins the reflector)? I'm hoping they will run for roughly an hour without needing a recharge. How long do you think I'll get?

Second-
These batteries on Alibaba are cheap, but they don't come with a charger and I'm not sure how to find an appropriate one. If you could provide me a link to a compatible charger, that would be perfect. I believe overcharging would be a problem with these batteries so a charger that has auto shut off, or an explanation of how long to charge would be helpful.

Any help greatly appreciated.
Thanks

RE: finding the right charger for 12 volt lithium ion batteries

Why on earth would you use an incandescent lit unit in a battery application?!?!? Crazy.

Why not:
http://www.ebay.com/itm/Strobe-Light-in-10-Amber-L...

Or these spectacularly tough, dependable xenon units: I found one laying in the surf 15 years ago running and it still works with the same battery!
http://www.ebay.com/itm/ONE-REAL-XENON-EMERGENCY-S...


Yes your crazy dangerous battery will run the badly chosen light for over an hour.

To charge your battery you will need a LiPo aware charger. I'd expect your best bet would be an RC charger.

If you went with Lead Acid batteries (+17AH) for about $50 a piece you could use more available chargers.

Anyway, back at the charger for the LiPo. You need to find one that can set to 12V worth of LiPo batteries.

This type might work:
http://www.ebay.com/itm/Imax-B6-2-6S-Lipo-Balance-...

Keep in mind you usually want temperature feedback to prevent a hot fire. Which the example above doesn't seem to embrace. Usually LiPo batteries of the style you're showing are used in engineered systems that have custom chargers provided.

Keith Cress
kcress - http://www.flaminsystems.com

RE: finding the right charger for 12 volt lithium ion batteries

(OP)
Hi, thanks for the info.

So, the reason for the project is I got 5 of these lights with the incandescent bulbs for cheap.
What I'd like to do with them is have them as stage lights for a band. Since they'll be moved a lot, and it can be hard to find 5 outlets in different locations, it would be best to not have to plug them into a wall.

given this info, what is the best and safest choice for powering them? and keep in mind cheapest?

Thanks

RE: finding the right charger for 12 volt lithium ion batteries

Roughly speaking, the battery you proposed will power the light you propose for
( 10 A-h / 4.3 A ) = 2.3 hours. ... probably a litle less because it's a high discharge current for that size battery.

For cheap, you could go with used car batteries.
I'd be inclined to go with motorcycle batteries, which are smaller and lighter, or with AGM or gel cell batteries as used in a UPS, which won't leak acid when knocked over. Those are all lead-acid batteries, so as ItSmoked suggested, they won't need a super fancy charger. It goes without saying, so I'll say it, that the batteries and the charger should be 12 volt nominal.



Mike Halloran
Pembroke Pines, FL, USA

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close