I was having a chat with one of my favorite customers today, who happens to own a Yamaha F115. Somehow we got on the topic of charging his trolling motor batteries, or a house battery to only be used to run his electronics while keeping his starting battery fully charged and ready to get him home.
I often see owners of Yamaha outboards discussing which is the best brand of battery isolator to buy. This is a shame. Because their outboard already has one.
Not only is this feature never mentioned by dealers, it almost seems like a secret that no one in the Yamaha dealer network is talking about. This is too bad. Because it works well. I know because I have had this cable in my F150 powered boat for years.
Before we get too much further, the part number you are looking for is 69J-81949-03-00 for the F115 through F150 and for the larger 4.2l outboards (some 225s and 250 HP and up), you need 6KW-81949-00-00. The reality is that so few people know about this capability of their Yamaha outboards, that there was no demand for these, so we stopped stocking them.
As with any kind of technical project, there are a few things you need to be aware of. Here are the things you need to know with before installing this house battery cable.
- For starters, the requirement for fusing this cable during installation cannot be understated. Not only is this a charging lead, but it can be part of a supply circuit as well. There is an internal fuse in the outboard where this connection leaves the outboard, but you also should fuse the lead within a foot of the battery as well, in case something happens to the lead between the battery and the outboard, and the battery tries to discharge back towards the outboard.
- The alternator that is in your outboard is designed to charge a lead acid battery chemistry. For this reason, you should not use this lead to try to charge newer battery chemistries, such as Lithium. Stick with lead acid batteries, such as sealed lead acid marine batteries, or AGM is okay.
- Remember that this is all about 12V systems. If you run a 24V trolling motor and were thinking about this for your trolling motor batteries, you will need at least more electronics to up-convert your 12V to 24V, and possibly other charging equipment as well.
If you are interested in doing this, but are unsuccessful at finding a source of the Yamaha cable to let you add this feature, just contact us and we can get you pricing on this cable as a special order part.