Battery Cable upgrade/OBC bypass

[Sergio]

Some LED light bars have a working voltage of 10v-40v and folks think that running them at a higher voltage will make them brighter

All that does is allow you to use a thinner gauge wire since it will draw less current, but the light output is the same.

One of Your original stock cables was on the wrong place, the cable with the pig tail between batteries #2(-) and #3(+), is supposed to be between batteries #4(-) and #5(+) with the pigtail on the #4(-).

That is the 16v tap when you use the 16v-12v reducer.

I think the best solution is to get the OEM style voltage converter that is plug-and-play on the precedent.

It mounts up front on the outside of the firewall and plugs directly to the existing harness.

The lights would work automatically since they are plugged to the dash harness.

If You want to add a Radio there is an extra +12v power wire in most models that you can use for the Radio.



What follows is my technical opinion and not a requirement or recommendation for a course of action:


If You were running a separate 12v battery, then a fuse block is required, but with a voltage converter it is optional and should only be used if it will actually simplify the wiring which typically is not the case on a Precedent with just a few accessories.

You can use inline fuses on the positive wires or no fuse at all if the wire gauge is 14ga and You don't mind powering down all accessories in the event of a short since that would take out the fuse on the +48v side.

Keep in mind that all wires should be sized according to the load requirement (don't use 18ga for a 15 amp light bar) and a fuse only protects the wire from catching fire in case of extreme current caused by a short and a voltage converter will not produce more than the rated output without blowing the fuse on the 48v side.

[yawood]

Originally Posted by Sergio

One of Your original stock cables was on the wrong place, the cable with the pig tail between batteries #2(-) and #3(+), is supposed to be between batteries #4(-) and #5(+) with the pigtail on the #4(-).

That is the 16v tap when you use the 16v-12v reducer.

I don't follow your logic there Sergio. If the positive side of your 16V is coming from the #1(+) then 16V would be at the #2(-) so that you are using two batteries. Surely if it came off #4(-) that would be 32V?

Duh!!! I can see why I'm wrong. the Blue wire is the positive for the 16V reducer and the negative will be attached to the black cable with the yellow bullet connector. In which case the pigtail wire should be on #4(-) or #5(+) to get 16V.

Sorry everyone for the confusion. I'll crawl back into my box now.

[yawood]

Originally Posted by Randy L

In regards to battery 3 the black pig tale is actually connected to a blue wire. Sergio asked me to get a voltage reading from the headlight connection and it was between 30 and 32volts. I wonder why the lights worked before the cable conversion but now they don't. When I first turned them on before charging the pack they flashed for a spit second and now nothing. I haven't found a fuse so the lamps must have been blown. Nice meeting you yawed, how are things down under?

Yes I could see that it was attached to the blue wire. Nice to meet you too. Down under is always great!!

[Randy L]

Thank you Sergio, yawood and NoleFan4Ever for your great advice and patience. You gave me the confidence to pull this off with out ruining anything. I feel good for an old retired Postmaster. Sergio, I will be getting a 48v to 12v reducer soon, most likely from Scotty. I do have 2 minor questions. Do you think I blew the entire headlight and tail light-horn harness or just have to replace the bulbs. The horn never really worked anyway. Last question, I want to install a voltage meter, can I safely remove the battery warning light and put the voltage meter in its place? Thanks again guys! I really like this forum.

[NoleFan4Ever]

Before long, you will be the one helping others....

And yes, you can put the meter there, but if you still have your OBC, I would keep it. Its codes are helpful if troubleshooting a problem with the charging circuit when you are a little bit of a novice. But if you remove the OBC, it is useless.

[yawood]

Originally Posted by Randy L

Thank you Sergio, yawood and NoleFan4Ever for your great advice and patience. You gave me the confidence to pull this off with out ruining anything. I feel good for an old retired Postmaster. Sergio, I will be getting a 48v to 12v reducer soon, most likely from Scotty. I do have 2 minor questions. Do you think I blew the entire headlight and tail light-horn harness or just have to replace the bulbs. The horn never really worked anyway. Last question, I want to install a voltage meter, can I safely remove the battery warning light and put the voltage meter in its place? Thanks again guys! I really like this forum.

I think you have probably just blown the bulbs. Thanks for the kind words.