Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Commuting Bicycle commuting is easier than you think, before you know it, you'll be hooked. Learn the tips, hints, equipment, safety requirements for safely riding your bike to work.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 09-01-07, 07:56 PM   #1
Ronocerous
Senior Member
Thread Starter
 
Join Date: Feb 2004
Location: Toronto, Ontario
Bikes:
Posts: 112
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Light Battery homebrew

The battery for my Planet Bike Insight 15W light is toast - doesn't hold a charge much and run time is down to 1/2 an hour. The battery is a 6V 4.5 A/H NiMH. The replace battery is $100 and I have no where near that kind of bread.

Can I use 5 "AA" rechargeable batteries? The ones I have here are NiMH 1.2 V 2650mah. Can I use five of these and if so, how would I attach them all together? And then attach them to the wire that hooks up to the light and to the power/setting button?

Thanks a lot! Winter is coming!!
Ronocerous is offline   Reply With Quote
Old 09-01-07, 08:25 PM   #2
ollo_ollo
Senior Member
 
ollo_ollo's Avatar
 
Join Date: Nov 2003
Location: Near Sublimity Orygun
Bikes: Still have a few left!
Posts: 3,535
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Better to use a 4.5 A/H sealed lead acid battery, probably $15-$20 & it will last you through the Winter.
(edit: Batteries.com shows 4.5 A/H for $16.50 @ 1.75 pounds weight & a 7 A/H for under $20 @ 2.8 pounds weight. You should be able to find similar locally & avoid the shipping cost)

Last edited by ollo_ollo; 09-01-07 at 08:31 PM.
ollo_ollo is offline   Reply With Quote
Old 09-01-07, 10:01 PM   #3
cyccommute 
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Bikes: Some silver ones, a black one, a red one, an orange one and a couple of titanium ones
Posts: 17,811
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 74 Post(s)
Quote:
Originally Posted by ollo_ollo View Post
Better to use a 4.5 A/H sealed lead acid battery, probably $15-$20 & it will last you through the Winter.
(edit: Batteries.com shows 4.5 A/H for $16.50 @ 1.75 pounds weight & a 7 A/H for under $20 @ 2.8 pounds weight. You should be able to find similar locally & avoid the shipping cost)
On the other hand, Ronocerous, you could get a 3.8, 4.2 or 5.0 ahr NiMH from BatterySpace for from $25 to $30. The battery is lighter, smaller, more rugged, and can be deeper cycled then a sealed acid. A much better choice.

You could also go to All Battery and get a 7.2V RC car battery with a 4.2 Ahr rating for around $30. They also have a 6V 5.0 Ahr NiCd battery for about $30 which is even more rugged than the NiMH. If you go with the higher voltage battery, your light output will be better at the cost of a slightly shorter bulb life. Output is about 50% higher.
__________________
Stuart Black
New! Pokin' around the Poconos A cold ride around Lake Erie
New! Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Days of Wineless Roads. Bed and Breakfasting along the KATY
Twisting Down the Alley. Misadventures in tornado alley.
An Good Ol' Fashion Appalachian Butt Whoopin'.
cyccommute is offline   Reply With Quote
Old 09-02-07, 08:27 AM   #4
Ronocerous
Senior Member
Thread Starter
 
Join Date: Feb 2004
Location: Toronto, Ontario
Bikes:
Posts: 112
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks for the ideas! So, does matching the 4.5 A/H matter that much or is there some flexibility there? R
Ronocerous is offline   Reply With Quote
Old 09-02-07, 10:38 AM   #5
rturpen
Member
 
Join Date: Jul 2007
Bikes:
Posts: 37
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Yes, you can

Wire them in series (connect + to - in a chain, connect the end - and + to the charger/light). You can connect to banks of these in parallel to extend the burn time. (connect + to + and - to - of the two chains)

If that makes no sense let me know I'll draw up a diagram.
rturpen is offline   Reply With Quote
Old 09-02-07, 11:32 AM   #6
bmclaughlin807
Crankenstein
 
bmclaughlin807's Avatar
 
Join Date: May 2006
Location: Spokane
Bikes: Novara Randonee (TankerBelle)
Posts: 4,038
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Ronocerous View Post
Thanks for the ideas! So, does matching the 4.5 A/H matter that much or is there some flexibility there? R
The 4.5 A/H tells you how much the battery stores... if the voltage rating is the same, but with a larger A/H rating, you'll get the same amount of light but with a longer run time.

So... no,, you DON'T have to match the amp hour(A/R) rating... the voltage rating of the new battery should be close to the old one, however. Slightly higher voltage will give a brighter light, but burn out your bulbs sooner.
__________________
"There is no greater wonder than the way the face and character of a woman fit so perfectly in a man's mind, and stay there, and he could never tell you why. It just seems it was the thing he most wanted." Robert Louis Stevenson
bmclaughlin807 is offline   Reply With Quote
Old 09-02-07, 09:08 PM   #7
cyccommute 
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Bikes: Some silver ones, a black one, a red one, an orange one and a couple of titanium ones
Posts: 17,811
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 74 Post(s)
Quote:
Originally Posted by bmclaughlin807 View Post
So... no,, you DON'T have to match the amp hour(A/R) rating... the voltage rating of the new battery should be close to the old one, however. Slightly higher voltage will give a brighter light, but burn out your bulbs sooner.
For an MR11 halogen the life is shortened but it's not really that significant. I've been doing this for years to these lights and this year was the first time I've ever blown a bulb. I figure I got about 8 years of use out of that bulb. I might have shortened the life by a couple of years...no big deal really.

One thing you can do, Ronocerous, is to by batteries with a lower Ahr rating and either wire them in parallel or, perhaps better, switch them out when one starts to dim. I've done that for ever too. At All Battery, the low Ahr rating batteries are slightly cheaper.

To get an estimate of the burn time for a battery, use the following equation:

Hr run time = (Ahr x Volts)/watts of bulb

This is the best you can get but in real life the time is probably a bit shorter. New batteries, in particular, take few cycles to get to full charge.

Considering that you have problems with the charge on the battery, you might want to look at a new charger too. For NiMH, you should have one that monitors not only the charge but also the temperature of the battery pack.
__________________
Stuart Black
New! Pokin' around the Poconos A cold ride around Lake Erie
New! Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Days of Wineless Roads. Bed and Breakfasting along the KATY
Twisting Down the Alley. Misadventures in tornado alley.
An Good Ol' Fashion Appalachian Butt Whoopin'.
cyccommute is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 02:39 AM.