This installment is about the charging system itself and is a precursor to the various components that make up the charging system, specifically the alternator and regulator.
Charging System
The electrical system is regulated to a mean voltage of 14.2 VDC. The 14.2 VDC level causes about the correct amount of current flow through the battery to maintain a battery in a fully charged condition once the battery is at 100% state of charge. Extended periods with higher than 14.2 VDC level could over-charge the battery at most temperatures.
Hooking additional loads into the system will generate as many recommendations as questions asked, if not more. There is really only one convenient place to do this and that is at the battery. There are aftermarket products that can be purchased to simplify the installation and are quite elegant when installed, but the battery terminals as the connection point into the electrical system for additional loads may not be a best practice even though this has been the accepted practice for years. What is required is an understanding of the operation of the bike's electrical system, and how we affect this system with what we do.
Connecting additional loads at the battery terminals does integrate these new loads into the electrical system load. These new loads are powered by the alternator when the bike is started, not the battery. This is because the alternator output is at 14.2 VDC and the battery voltage is at approximately 12.7 VDC. Voltage is the electrical system pressure and you cannot force 12.7 VDC into a 14.2 VDC system. The battery does power these loads if used with the bike is not started.
When you do connect loads to the battery, using a relay to ensure the loads are off when the bike is not started is a prudent consideration. Not doing so will require you to ensure the loads are turned off; however, we have all left loads on that drain the battery at the most inappropriate time.
I think we can all agree that the charging system is at 14.2 VDC and the battery is at 12.7 VDC. Because of this, all loads are now being provided operating power from the charging system through the bike's electrical system, even the loads attached to the battery terminal(s). I mention this because voltage, electrical pressure, works the same as any other fluid system we know. You cannot force 12.7 VDC into a 14.2 VDC system, just is not going to happen. That is until the electrical system voltage drops below that of battery voltage, then the battery will supplement the electrical system power requirements.
When the battery is fully charged to a 100% state of charge after the bike has started, the battery is in essence a “passenger” until it is required to supplement the electrical system power requirements, or start the bike again.
The wiring to the battery as designed has no additional loads connected, has very little voltage/current flow going through once the battery has been brought to a 100% state of charge; however, when we attach loads to the battery terminal(s), there is increased voltage/current flow through the wires to the battery. I surmise that there is a possibility that this additional voltage being supplied through the wiring to the battery, not as per the design intent when built in my opinion, could have an adverse affect on the battery even though the power is meant to be used by the external loads connected to the battery terminal(s).
I found an article on the internet that mentions that the additional current flow to the battery terminal could potentially be detrimental to the battery and result in having the battery in an overcharged condition. This is because there is no control over where the additional current will flow at all times.
Charging System
The charging system has evolved considerably from the '60s when I started driving in the '60s. Generator(s) with the external black box regulator, vacuum wiper blades – never did work well, 3 on the tree standard shifts, very few electrical accessories, lights dimming, always having issues in the winter starting, being able to remove a battery with the car running and putting in a replacement (can't do that today) and such.
The charging system design intent to charge the battery was at the forefront of the electrical system back then. Today, the charging system is in my opinion a system to power the vehicle with battery charging as a secondary roll. Vehicles start so much easier today, and require a smaller battery to do this. If the design intent is met, the battery is depleted approximately 3%, but topped up quickly.
Conversely, the additional power requirements to support the plethora of electrical loads has increased significantly. Power seats, heated seats and hand grips (steering wheel), car seat cooling, navigation systems, just about every vehicle is fuel injected – can't think offhand if there are new cars with a carburetor, on our bikes – auto air ride suspension. Our bikes are equipped with Navigation systems, heated seats/hand grips, USB and other 12 VDC connections. A lot of bikes do not have these as a factory install, but the owners want to have the same functionality. In this regard there is a lot of discussion on the various forums regarding alternator amp sizing, not much on a larger size battery.
Another thought is having more than one battery on our bikes, even read of people installing car batteries. This is an interesting idea. It can provide additional power when at a camp site, when the bike is not operating, the second battery could be a deep cycle battery and be isolated from the starting battery so that you would always be able to start your bike and move on.
The only caveat I have regarding this is the charging capacity of the GW with an OEM alternator. Adding a second battery to the electrical system is a modification that would be well served by the owner doing a load survey of their bike. Discharging the second battery, and using the bike's electrical system to charge after use needs to be well understood, wired and executed, especially if you are using the older internal OEM alternator in these older GWs.
I have had experience with this having lived on a 40 foot boat for 5 years, and previous to that owning a 30 foot boat that was used every weekend during the boating season with solar panels to supplement the battery charge when we were at anchor, and to fully charge the batteries during the week when we were at work. I also had sufficiently large enough alternators to compensate for the additional charging requirements.
