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Battery Maintenance 101

And How to Use Tenders

By Bandit, Jason Mook, Battery Tender Crew, and Jeff Holt
10/27/2021


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Can't have your battery fail now, although this Sportster was probably magneto driven.
Can't have your battery fail now, although this Sportster was probably magneto driven.



BIKERNET BATTERY TENDER INVESTIGATION—How to use battery tenders? We are on the hunt. A friend kept his bike on a tender 24/7. But when he rode to his girl’s house and spent the night, the bike was dead in the morning.

So, what's the proper way to use a tender. Many folks recommend keeping their bikes on tenders all the time. I don’t like leaving a bike on a tender overnight or for long periods. If something goes wrong with the battery, the tender or garage circuits, your garage could burn down and perhaps your house, not to mention your Prize Possession.

This is an old charger. It works on 6 or 12 Volt batteries, but you need to keep an eye on it and unplug the bastard before you go to bed.
This is an old charger. It works on 6 or 12 Volt batteries, but you need to keep an eye on it and unplug the bastard before you go to bed.



Jason Mook, the owner of Deadwood Custom Cycles recommends putting your bike on a charger or tender once a week, charge it and then unplug it. You may need to charge more often depending on how new your bikes is and the constantly operating electronics, like the clock or security system.

We are also looking into how to check your battery. Our ’69 Panhead just had an issue with a recently replaced battery. At fully charged, it worked to electrically start the bike, but with the slightest draw and it didn’t have the power to turn over the engine. Jason replaced the battery, but the damn things are expensive to replace once a year. The guys at Battery Tender said most batteries only last three years or maybe four.

Here are CTek battery leads.
Here are CTek battery leads.



Let us know your thoughts and experiences. I will also reach out to some of the manufactures. According to the Battery Maintenance guys a smart trickle charger will start charging your battery when is reaches about 12.5 volts. It will charge it to 14.7 volts and then back off. So, if you measure your battery and it indicates only 12 volts or less, you’re probably in trouble and need a charge.

Another tip is to keep your battery off the shop floor, concrete or steel. Don’t let it set around, unless you slip a chunk of plywood under it. The same applies in your bike. Don’t just mount it against bare metal for two reasons, maybe three. The steel will pull power out of the battery, the steel is not protected from battery acid or corrosion from the battery terminals, and I try to cushion a battery as much as possible in its container. That has several positive effects on battery performance. It slows or prevents damaging battery motion messing with battery acid or even the plates. That will kill a battery fast. Padding will prevent dangerous cracking and acid leaking, which will damage everything including your paint and frame. It will also prevent damage to your battery connections and leads. A broken wire on the road can be a serious problem, especially if it was the lead from the voltage regulator.


This is a 12 Volt 750ma Battery Tender. LED lights tell you if it's charging or in neutral. It's a very slow charge, so be patient.
This is a 12 Volt 750ma Battery Tender. LED lights tell you if it's charging or in neutral. It's a very slow charge, so be patient.



So yeah, it's best to keep tabs on your battery and keep it charged. The most common battery chargers you'll come across are trickle chargers and smart chargers. A trickle charger is constantly working and slowly trickling a small charge into the battery, even when it's fully charged.

Most chargers these days come with quick connect 2-Pin SAE Waterproof Wire Harness Plug cables. These quick connect cables are extremely handy as they allow you to easily plug and unplug the charger while the battery is still in the bike. The cables are usually a universal fit and will work with PulseTech, OptiMate, Yuasa, Battery Tender, BikeMaster, except Ctek battery maintainers. They use a different connector because of the Battery Tender patent.
 
This is the common Battery Tender lead with its protective cap.
This is the common Battery Tender lead with its protective cap.


 

When you get your smart charger, install the battery leads permanently to your battery terminals and route the tail end somewhere inconspicuous, but where you can still easily access it. By doing this you'll save yourself the hassle of always having to remove the seat or side cover. 

If the battery charging/maintenance unit you have doesn't have an in-line fuse on the connection cables plug your unit into a surge protector to help protect your electrical system from a sudden power surge.

In addition, if you aren't using a smart charger, it's best practice to remove the battery from the motorcycle. That way if the charger does cause an issue with the battery (overcharging, boiling, etc.) the damage will be confined to the battery and won't harm your motorcycle or electrical system.

This is a 6-Volt Battery Tender for vintage batteries.
This is a 6-Volt Battery Tender for vintage batteries.



If the battery side of your cable came with ring terminal ends, see if you can source a SAE 2-pin lug with open ended fork terminals. Or clip the end of your ring terminals to make your own forked ends. The benefit of the fork terminals is that they are easier to mount to the battery posts than completely removing the screws to install the ring terminals.

And if you have multiple bikes, you can swap the leads from one battery to another much faster and easier.

I bought this at Cycle Gear for about five bucks. Not sure if it's still working.
I bought this at Cycle Gear for about five bucks. Not sure if it's still working.



If you have your motorcycle dialed in with smart charger and a quick disconnect cable, that doesn't mean you shouldn’t look at your battery occasionally.

For optimum battery life and performance peek under the seat (or wherever your battery is located) occasionally, and make sure it looks normal. Make sure there is no swelling, leaking or heavily corroded cables.

This isn’t completely wise. Batteries are dangerous. The acid can blind you. Don’t peak, stand back, wear eye protection, take off your seat and check the battery area. If you notice any problem, cracking, leaking, etc. remove the ground strap first. Use a towel and or rubber gloves and get your battery away from your chopper and preferably out of your home or shop. 

Here's a traditional super-smart 6-Volt Battery Tender.
Here's a traditional super-smart 6-Volt Battery Tender.



Inspect the terminals and clean off any corrosion or muck that may have accumulated. If your battery terminals don't have little rubber covers, there are gels you can put on the terminals/posts to help prevent corrosion. Watch out for loose terminals. 

Secure the battery in the battery compartment. A battery that moves around can lead to some major issues. If your battery compartment doesn't have a brace or sturdy rubber strap you can use foam blocks as padding to secure the battery. Foam blocks are also great if your new battery is shorter or isn't the same dimensions as your old battery. 



Jeff G. Holt brand director and editor of V-Visionary says the following about battery tenders, “I am forever in need of battery tending. From my personal bikes to the Harley-Davidson and Indian test bikes, I frequently have battery drainage issues.

I would say that personally, battery failure is the main mechanical factor in me not getting rubber on the road. I combat this by using a good quality battery tenders that both charge and condition the battery internally.”

You don't want your battery to act up if she calls...
You don't want your battery to act up if she calls...



J E F F G. H O L T
V-Twin Visionary
626.391.3143
@jeffgholt
@vtwinvisionary
VTWINVISIONARY.COM

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Reader Comments


Sorry guys, but the advice to not put your battery on a concrete floor is long outdated. Nothing will leak through todays' plastic cases.

Also, modern tenders can be left on all the time. I just replaced an eight-year-old battery in my bagger, thanks to my tender.

Doc Robinson
Adelaide, SA, Australia
Thursday, November 11, 2021
Editor Response Thanks for your input. You are the Australian tech master.
--Bandit

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