Tuesday, 21 February 2017

The Search For Electrical Overhead

Due to the additional electrical load being placed on the bike from the EFI system, the charging system needed some attention. It was suspected from the very beginning of the project that the original reg/rec may not able to cope with the constant drain on the system from a high pressure fuel pump and twin headlights. This became very apparent as the bike was being used more and more recently.
The battery could not be kept charged when either the dipped beams or main beams were switched on. There was a definite drop in battery voltage depending on whether the lights were switched on or not and it was noticed that the reg/rec was getting quite hot after night-time rides so it was likely that the reg/rec was going to fail sooner rather than later.

A new Shindengen FH020AA mosfet reg/rec had already been purchased for an upgrade further down the line but given the circumstances, the upgrade was moved to the top of the priority list. The installation of the new reg/rec was relatively straight-forward. The FH020AA is quite a bit bigger than the OEM reg/rec but still fits under the fairing in the same place. Just about. One additional hole had to be drilled in the mounting plate to accommodate the wider hole spacing of the FH020AA and the standard connector was chopped from the loom and replaced with the dual connectors required for the FH020AA.

FH020AA vs OEM mc22 reg/rec

An immediate improvement in voltage regulation and stability was observed with the FH020AA fitted and the reg/rec merely ran warm to the touch as opposed to hot. Although, since the reg/rec can only improve regulation efficiency and can not force the stator to provide any extra power, the bike was still a little short of electrical headroom. It was not bad enough to risk running the battery flat during a long night-time ride but rather meant that battery voltage with the lights on at idle tended to hover around 12V as opposed to the 14V which was observed at idle with no lights. When a current clamp was placed on the battery earth strap, it became apparent that with lights on, the predominant flow of current was out of the battery. As such, a way of either a) boosting the generated power or b) reducing the electrical load on the bike had to be found. Of the two, option b) was clearly the preferred route. Given the headlights represented the single largest current draw on the electrical system, they were the chosen target for modernisation.

After much deliberation, research and changing of mind back & forth, it was decided to install LED bulbs. The options were either HID or LED but eventually the LED won out due to being actually able to package the ballasts in the front of the bike, being more adjustable for beam pattern and having lower overall current draw although they were almost twice the cost of the HIDs for a quality set from a reputable manufacturer.

Each H4 LED bulb is rated at 20W compared to the 60W/55W rating of the standard halogen units so, in theory, a set of two should have freed up c.6A capacity which would be more than enough to cover the additional load the fuel pump, lambda heater & injectors placed on the system. Before installing the LEDs, a charge current of -7A (draining battery) at idle with dipped beam on and -6A at idle with main beam on was measured. With the LEDs installed, charging current was measured at +3A at idle with both dipped and main beams on, leaving ample headroom on the charging system.

The physical installation of the bulbs was reasonably straight-forward. The heatsinks on the back of the bulb made it all a bit bulkier than the standard setup but the heat sinks are well hidden given they are black in colour. The two small ballasts found a nice place to sit either side of the clock stay bracket where they do not interfere with anything else. Getting the beam pattern right took the most time but the adjustment in the bulb housings worked a treat. There is also the advantage that the LED headlamps are quite a bit brighter than the halogens which makes night-time riding quite a bit more enjoyable.