Top Navigation  
U.S. Flag waving
Office Hours Momday - Friday  8 am - 5 pm Pacific 1-800-835-2418
Facebook   YouTube   Twitter
 Home Page
 Current Issue
 Article Index
 Author Index
 Previous Issues

 Kindle Subscriptions
 Kindle Publications
 Back Issues
 Discount Books
 All Specials
 Classified Ad

 Web Site Ads
 Magazine Ads

 BHM Forum
 Contact Us/
 Change of Address

Forum / Chat
 Forum/Chat Info
 Lost Password
 Write For BHM

Link to BHM

Get Powered Up! Certified Energy Manager Jeff Yago answers your alternative energy questions

Wondering about a great new energy-saving device
you found on the Internet? Then CLICK HERE!

Sorry. Jeff no longer answers questions online.
This will remain as a searchable
resource for all BHM website visitors.

Archive for the ‘Lithium-ion (Li-ion)’ Category


Battery efficiencies for Solar LED lamp

Thursday, April 9th, 2009

Hi Jeff,

I am building a solar LED lamp, and I am trying to find the overall efficiency of this system.

There are three options of rechargeable batteries that I am looking at and they are NiCd, NiMH and Li-ion.  These three batteries have different efficiencies due to their different charge and discharge methods.

Can you tell me how can I find the efficiency of this batteries?

I was wondering if for each one of them I have to build a protection circuit as well.

Which battery will you recommend if I want it to be cost efficient and also reliable?

Thanks a lot.



Several years ago I wrote an article to test which type of flashlight and flashlight bulb gave the most bang for the buck.   This article describes how I tested them to see which battery-lamp combination provided the longest run time.

I suggest you try a similar test using the different batteries you are considering as this way you will not need expensive test equipment or calculations.  Here is the link to this past article:

Good luck,

Jeff Yago


Lithium-ion batteries for solar lighting

Wednesday, March 11th, 2009

Dear Jeff,

Thank you for writing such an informative article on outdoor solar powered lighting, I do however have a few questions which i would greatly appreciate answers to.

The first of which is to do with the type of battery used in such a system. Is it possible to use a lithium-ion power battery to charge a system similar to that you have described. If no, why not and if yes, what should I look out for.

My second question is to do with the charge controller, in figure 7 you have a picture of a Sunlight-10 charge controller (the one on the right).  Can this devise be used in conjunction with a lithium-ion battery or does this devise only work with more conventional lead acid batteries. If so can you recommend another type of charge controller with similar features to the Sunlight-10 that can be used with a lithium ion battery?

Thank very much for your time and I look forward to reading your response.

Kindest regards

Kane Miller


The main reason lithium-ion batteries are not used much for solar is they are not making them large enough yet and the cost of what they do have is so far out of sight that it does not make sense.  Any short-comings with AGM or Gel batteries are easily made up by their much lower cost.  Sharp is working on a 18 Kwh lithium-ion for solar home power but these are thousands of dollars right now.

I suggest that you don’t make this any harder than it has to be right now,

Good Luck,

Jeff Yago



Copyright © 1998 - Present by Backwoods Home Magazine. All Rights Reserved.