Perhaps every boat, car and camper needs a set of retail adapters for emergencies. Commercial adaptors look like regular batteries but heavy plastic and hard to service.
Disposable alkaline batteries, lithiums and recharables like Nickle Metal Hydride or Lithium Polymer can be obtained most anywhere now...In widely varying sizes and all sizes between!
Exotic chargers, PCB temp control and voltage controlled chargers are not addressed here...
Please be careful, recharge OUTDOORS on a hard fireproof surface and clear from all combustables. Cover or contain especially LiPO cells. Use over temp and voltage/current monitored re-chargers for THAT cell type and pack size with voltage and current + temprature regulation.
Ok on to the various battery sizes & dimisions!
Step 1: Battery Sizes Charts (length & Widths for Fitting Adaptors)
Use spacers or adapters and retail converters...these should be within .5mm of actual sizes for snug fit.
Use springs, spacers or magnets for slight adjustments 1-5mm.
Step 2: Now We Know Lenghts...how to Make 'Easy' Diameter Changes
See 4x 'C' cells for a 3x D batteries pack below..
3xAA for D cells can be made from household materials.
hum...4xC a little long for the light below...
NOW onto more mods for lengths...
Step 3: Exact Size Is Everything ! Mods for Length and "slugs/springs"
1) Layout the original old "dead" cells you have at home
2)Adjust wrapped (width modded) replacement cells for required appliance voltage and lengths. Use Tape or re-size with household paper/foam etc.
NOTE:Alkaline cells are 1.5V and NiMH rechargables 1.2v ea. avg.
3)Please be aware Lithium cells are 3v and some LiPo packs are 3.7v...adjust accordingly! if using 1.5v alkalines.
4)Modify legths from chart. Measure and use nuts, springs or even remove original springs or spacers from flashlight/radio bases & use higher voltages for brighter (rated) bulbs. Most devices tolerate slightly higher voltages as battery packs voltage rated are not "under load" so internal resistance will limit voltages.
NOTE: Some battery sizes are EXACT matches for lengths:
Use 2x 1/2D for full D cell
4xC for 3xD cells....etc...
3xAA or 4xAA packs for multi D cell (parallel)
Bulbs are rated for number of CELLS and not voltage so note the recommended ratings
TIP: Specialized Series and Parallel adapters can get voltages above 12-15v for devices originally sized for 3-4 "D" cells by using multiple 1.2v NiMH or high power 3.7v LiPO battery chemistry as direct replacements for AA/C & D cells.
5) Keep sizes on hand or in car/boat. Specialized adaptors for Lantern sized, D, C and CR123 cells can often be made from cheaper but smaller AA cells!
Tip: Pry open 9v cells and find 6-9 AAA or 'button' dry cells!
These vary by maker but are useful in a pinch for watches, toys or other devices when only a 9v is avail but require AA/AAA or coin type batteries!
Step 4: Summary: DIY Spacers & Slugs (adjustable Battery Spacers From Junk in a Pinch!)
Old Button cells(dead), older smaller cells N sized or L sized, hardware like a 5/16 Bolts and hex nuts can be "filled" with solder.
Plastic 'tubes' or teflon tape will insulate from walls or other cells for width.
Springs and adjustments to original devices can be used to accomidate most batteries ...see below...
Step 5: 9v Specials...
Or pry off the top from a used 9v, use the AAA cells inside and the collector to wire to a 9v device, use the AA or AAA cells to make a new "pack" for 3, 6 or 9v cell combos.
Step 6: Finish
in a pinch...use the old AA or AAA cels EVERYWHERE! just tape, sizes and set lengths & widths from the charts!