Charging Battery on a Nightster
#1
03-17-2009, 11:40 AM
#2
03-17-2009, 11:44 AM
#4
03-17-2009, 03:05 PM
Elite HDF Member
A battery tender will not charge a completely dead battery. If you have, I believe, the Battery Tender Plus, then it will act as both a tender or as a charger. You'll need a charger. If your brother has a battery pigtail installed on the bike, then a Tender Plus may be enough to charge the bike to start, but only after sitting on charge probably overnight. 
#6
03-17-2009, 06:50 PM
Road Master
#7
03-18-2009, 08:06 AM
Road Captain
A battery tender will not charge a completely dead battery. If you have, I believe, the Battery Tender Plus, then it will act as both a tender or as a charger. You'll need a charger. If your brother has a battery pigtail installed on the bike, then a Tender Plus may be enough to charge the bike to start, but only after sitting on charge probably overnight.
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#8
03-18-2009, 09:48 AM
Huh? Of course a Battery Tender will charge a completely dead battery (assuming that the battery is not sulfated or otherwise damaged/defective). It will just take a very long time because you're only looking at a 750 to 800 milliamp charge rate. That means that it would take about 25 hours for a Battery Tender to charge a 20 amp-hour motorcycle battery while a 6 amp bench charger would only take 3.3 hours. Even a Battery Tender Plus will only manage a 1.25 amp charging rate so it would need 16 hours to recharge the battery in my example.
#9
03-18-2009, 03:18 PM
Elite HDF Member
, but if you say so. 
Last edited by WVHogRider; 03-18-2009 at 03:21 PM.
#10
03-18-2009, 03:52 PM
Road Captain
The following comes verbatim from the manual for my 800 milliamp waterproof model:
TIME REQUIRED TO CHARGE A BATTERY:
The WATERPROOF DELTRAN BATTERY TENDER® International Battery
Chargers charge at a rate of either 0.8 Amps (0.8 Amp-Hours per hour) or 1.25 Amps (1.25 Amp-Hours per hour). Therefore, a fully discharged 15 Amp-Hour battery will take approximately 15 hours or 9.6 hours respectively, to recharge to 80% capacity. Some large automotive or marine, deep cycle type batteries may take several days to fully recharge.
WORKING WITH A DEAD BATTERY OR A BATTERY WITH A VERY
LOW VOLTAGE:
If you try to charge a dead battery having a voltage below 3 Volts, the
WATERPROOF DELTRAN BATTERY TENDER® International Battery Chargers will not start to charge because an internal safety circuit prevents the battery chargers from generating any DC output voltage.
NOTE:
If a 12 Volt, Lead-Acid battery has an output voltage of less than 9 volts when it is at rest, when it is neither being charged nor supplying electrical current to an external load, there is a good chance that the battery is defective. As a frame of reference, a fully charged 12-Volt, Lead-Acid battery will have a reststate, no-load voltage of approximately 12.9 volts. A fully discharged 12-Volt, Lead-Acid battery will have a rest-state, no-load voltage of approximately 11.4 volts. That means that a voltage change of only 1.5 volts represents the full range of charge 0% to 100% on a 12-Volt, Lead-Acid battery. Depending on the manufacturer, and the age of the battery, the specific voltages will vary by a few tenths of a volt, but the 1.5-volt range will still be a good indicator of the battery charge %.
The WATERPROOF DELTRAN BATTERY TENDER® International Battery
Chargers charge at a rate of either 0.8 Amps (0.8 Amp-Hours per hour) or 1.25 Amps (1.25 Amp-Hours per hour). Therefore, a fully discharged 15 Amp-Hour battery will take approximately 15 hours or 9.6 hours respectively, to recharge to 80% capacity. Some large automotive or marine, deep cycle type batteries may take several days to fully recharge.
WORKING WITH A DEAD BATTERY OR A BATTERY WITH A VERY
LOW VOLTAGE:
If you try to charge a dead battery having a voltage below 3 Volts, the
WATERPROOF DELTRAN BATTERY TENDER® International Battery Chargers will not start to charge because an internal safety circuit prevents the battery chargers from generating any DC output voltage.
NOTE:
If a 12 Volt, Lead-Acid battery has an output voltage of less than 9 volts when it is at rest, when it is neither being charged nor supplying electrical current to an external load, there is a good chance that the battery is defective. As a frame of reference, a fully charged 12-Volt, Lead-Acid battery will have a reststate, no-load voltage of approximately 12.9 volts. A fully discharged 12-Volt, Lead-Acid battery will have a rest-state, no-load voltage of approximately 11.4 volts. That means that a voltage change of only 1.5 volts represents the full range of charge 0% to 100% on a 12-Volt, Lead-Acid battery. Depending on the manufacturer, and the age of the battery, the specific voltages will vary by a few tenths of a volt, but the 1.5-volt range will still be a good indicator of the battery charge %.
Furthermore, if you look up the manual for the Battery Tender Plus, you'll find that even those models will not charge batteries that drop below 3 volts.
I say again, if the battery is not damaged, even a little Battery Tender Jr or waterproof model will be able to fully charge it, you're just looking at it taking a few days. Most of us (myself included) are not willing to wait that long and would rather just throw the battery on the 10 amp bench charger for a couple hours instead, but if you don't have any other options, the maintainers can do it.
Last edited by Zenmervolt; 03-18-2009 at 03:55 PM.