[wilythek]

My wife drives a Honda Helix 250. She has and electric jacket liner, that I believe draws 77 watts. Not knowing but I'm guessing that the alternator may be too small to keep the battery up to full charge if she rides with the jacket turned on, even 1/2 way for 2-4 hours. I have a spare 12 AH motorcycle battery and was thinking what if I were to charge it full up and hook it up parallel to the bike battery? This would probably be enough power for the bike and the jacket for the 2-4 hours. But the question is, is this too much of a load for the alternator possibly burning it out???? Any thoughts or suggestions will be appreciated.
Thanks,
Bill...

 

[Duster]

To be able to hook up 2 batteries in parallel, they must be identical...
otherwise, the charging system will keep trying to overcharge the
lower rated battery, & the larger battery will never be fully charged.

 

[haze]

I charge an auxiliary battery on the bike. Its a PEAK compact battery jump start box. I charge and run power from the 12Volt outlet on the box. Bought the box at PEP Boys for $19.95 after rebate. Battery in the box is 12AH which should power your heated gear with an assist from the bikes charging circuit. The jump start box is small, light and has a built in charging circuit so I can recharge from the bike 12v system when riding. Or charge from AC power when available. You can buy one of these boxes and strip out the charger to use with any auxiliary battery.

Another option is to use a Voltage Sensitive Relay (VSR) 12VDC for Battery Isolation - Specifically designed for charging from an Auto/Boat. Check out the Photo and Schematic. It turns on at 13.3 volts (which protects your aux battery from being used as a starting battery by switching on only once the staring battery is fully charged). And cuts out at 12.8 volts (which keeps you from draining your starting battery when using your aux battery without the engine running). A nice feature is a little LED light that indicates when it's engaged.

Amazon.com: Voltage Sensitive Relay (VSR) 12VDC for Battery Isolation - Auto/Boat/RV: Automotive

 

[mikeyMarine]

hook the jacket to the spare battery.

 

[wilythek]

I already did a test with the aux battery. It's 12AH and I ran the jacket on 1/2 draw. The jacket controller shut down and the battery lasted about 3.5 hours. When I tested it with my meter it indicated 5.4 V... I don't know if that was correct or not so I tried some other tests with the old meter and they also were screwy, so after about 12 years of use I threw the meter in the trash. I recharged the battery yesterday with my battery charger and this morning after I let it rest for 24 hours it reads 12.54 V (with a new meter). I'm hoping I didn't really hurt the battery, amp wise...


Does anyone know if the 5.4 V reading could have been correct???

PS the guy that we bought the bike from put a 14 AH battery in the scoot.

 

[Quantum Mechanic]

Sadly, if the battery only reads 12.54v then it's only really fit for the recycling dump as a fully charged battery should read 13.5v minimum.