wr450 battery charge

[Felippe Vieira - Fórmula FEI]

Hello,

We are using a wr450 engine for the first year and we have a battery charge problem, its not charging the battery.
I had already tested the alternator and the rectifier separated and its ok!when we connect the whole system, the battery don't charge. May the alternator wasn't able to supply all car's system(the engine was carbuereted and now we are using electronic fuel injection)what can i do??

thank you,

Hélio

[Felippe Vieira - Fórmula FEI]

Hello,

We are using a wr450 engine for the first year and we have a battery charge problem, its not charging the battery.
I had already tested the alternator and the rectifier separated and its ok!when we connect the whole system, the battery don't charge. May the alternator wasn't able to supply all car's system(the engine was carbuereted and now we are using electronic fuel injection)what can i do??

thank you,

Hélio

[Pete Marsh]

There is an enduro bike with a version of the WR450 engine. The one that probably donated your electric starter? It has a headlight, as well as the electric start, and may have a larger capacity generator to suit.

Pete

[Kirk Feldkamp]

Check to make sure you don't just have an old, dead battery that won't take a charge anymore. If your rectifier is making the proper voltage under load (ie it should be charging), then that points to the battery for me. What steps have you taken to diagnose that the battery is still good?

EFI boxes generally don't draw very much power... *especially* if you're only running one injector and one coil. As Pete said, the stock bike has a headlight, which is a significantly larger load than an ECU... but not necessarily more than a fuel pump, which the bike doesn't have. What fuel pump are you using, and is it 'properly' sized? You don't have a whole lot of choices for 'properly' sized pumps in this case, but there are some available now because of the motocross and ATV fuel injected singles.

[mrrc]

If you get an ammeter and connect it between the output of the rectifier and the battery then you can see if there is a current draw. You can also disconnect the battery fully once the engine is started and see if the alternator can power the car on its own.

One reason a battery won't charge is if the battery is old or TOO BIG. Charging batteries in parallel or one that is too large will draw so much current, dragging the voltage output down and then the battery won't fully charge.

Don't buy cheap batteries for your FSAE car either, and always monitor the voltage and keep it above ~12.3 V when unconnected. It's easy to kill a battery fast if you drain it too much, then when your battery gets bad the engine doesn't fire properly, and then the spark plugs can get fouled.