TOPIC: Battery not charging

Okay guys, what would be the first thing to check if my battery is not charging? As many of you know, I've been playing around with solenoids because I had a starting problem. That is still sort of erratic too. Wiring? Stator? Haven't had any problems with charging all summer, ran around a bunch yesterday, take it out today, battery too low to start the motor. Any ideas?

Thanks!

Frank

Frank take your battery to napa and have them LOAD test it. Thats where I would start if you don't have a tester yourself. Battries take a beating in a boat!

Gee Pete, never even thought of that. I pretty much have to get a new battery every year for the hot rod because driving it around bounces my battery to death. Need a gel cell, just hate to pop for it. I put about 200 gallons of gas through this little boat this summer, lots and lots of bouncing, that's a great idea. I'll do dat.

Thanks!

Frank

Had my buddy who used to be the battery guy for NAPA, now works as a store manager, store I used to work at, load test my battery, he said it's fine, charge it. So what's next?

Frank

test all your wiring. you have a diagram yes? if the wiring is ok check the stator and rectifier. If you can't test them per the manual then you may have to try the swap method

Rectifier is probably toast...or you've got a short\bad wire somewhere.

With a meter connected to the battery and the motor off, take a reading...now start it...where did your numbers go(up, down, dropping, climbing, steady)?

What am I looking for? 12 Volts, or just changes in voltage? And it would be just the charging system - rectifier or stator and the wires in between right?

I was gonna pull the motor yesterday, but got feeling optimistic about an bright sunshiny Indian summer coming on a weekend soon...

Frank

Do an ohms check on the stator ( wire to wire ) then one wire to ground. ( post results.

---

It is usually the rectifier ( harder to explain the test )

---

Not expensive to replace.

Okay, maybe tonight if it's not raining. Thanks!

Frank

PC1000 wrote:

What am I looking for? 12 Volts, or just changes in voltage? And it would be just the charging system - rectifier or stator and the wires in between right?

I was gonna pull the motor yesterday, but got feeling optimistic about an bright sunshiny Indian summer coming on a weekend soon...

Frank

You should have 12ish volts before starting...after starting, it will drop slightly from the load on the system, then slowly come back up if your charging. If your not charging, the voltage will remain steady or drop very slowly(slightly).

Jim sent me an easy rectifier test...I'll dig it out of email and post it a little later if he doesn't chime in with it. I'd be willing to bet that's your problem though...luckily rectifiers are cheap.

Thanks man. Just got home, long day, beat. Maybe play with it tomorrow night if I can. My kid has a multimeter and knows at least how to read it.

Sure appreciate all the help and advice.

Frank

Running an old merc @ WOT will charge up to 20 volts, thats why it is so inportant to keep all wires clean and in good cond. And the Batt secured to the floor,throw away those wing nuts on it to and use nylocks, bouncing cables will loosen up the terminal ends and cause a ele. spike's and short out charging systems,switch boxes, fuel gauge's,etc

By the way thats a great PIC of that boat!

Rectifier Test sequence for ‘60s ‘70s ‘80s Mercury O/B

Terminals A & C are different than Terminal B. Terminal B is the + terminal. (you will find a tiny + symbol near it)

Dis-connect all leads & use R x 1000 on your meter.
With the red lead plugged into the (+) port on your meter and the black lead plugged into the (-) port on your meter:

Red lead to ground (rectifier metal case or powerhead) and black lead to A = continuity
Red lead to ground and black lead to C = continuity
Black lead to ground and red lead to A = NO continuity
Black lead to ground and red lead to C = NO continuity
Black lead to B and red to A = continuity
Black lead to B and red to C = continuity
Red lead to B and Black lead to A = NO continuity
Red lead to B and Black lead to C = NO continuity

There is also a test sequence for the stator if your rectifier passes the tests.

To avoid the voltage spikes I simply replace the rectifier with a regulator that has a rectifier built into it.
Then you get a steady 13.8 volts - no spikes!!
Merc marine part number 883072T, 883072T1, or 883072T2 available on eBay for about $40+ used. They are pretty dependable in a used condition off a dead Merc v6.
Thom

Thanks Doc, I'll check it out maybe tonight. Wouldn't ya know right when I get this baby dialed in something goes? Of course, I figure I put about 200 gallons of 93 octane through it this summer. Most of it was for testing though.

Tell me Doc, if I get a regulator, what's with the 5 wires? Looks like two red, two yellow and one black. I'd just use the yellow and black is ground? Or?

Also you might remember you suggested I jump from the rectifier to the battery post on the solenoid for some reason I can't remember right now. If it is the rectifier that's bad and I get myself one of those regulators would I still need or want a jumper there?

Thank you for the help, I sure do appreciate it!

Frank

Ponyboy wrote:

Running an old merc @ WOT will charge up to 20 volts, thats why it is so inportant to keep all wires clean and in good cond. And the Batt secured to the floor,throw away those wing nuts on it to and use nylocks, bouncing cables will loosen up the terminal ends and cause a ele. spike's and short out charging systems,switch boxes, fuel gauge's,etc

By the way thats a great PIC of that boat!

I keep the battery secured to the floor, but it's in a battery box. Think I should take it out and strap it down to insure no movement?

I have not had any problem with those ss wing nuts loosening. Just the opposite, it pretty much it all I can do to get them lose! But go to nyloks anyways ya think? That would mean I'd have to start carrying tools! Guess I need to do that anyways eh?

All I have powered in this boat right now is a tach. I may add lights next year, but really don't want to be boating in the dark anyways.

That sig pic was stripped off a video, so the resolution isn't hot. I want one like that from a good camera so the resolution is better. Maybe next year!

Thanks!

Frank

PC1000 wrote:

Ponyboy wrote:

Running an old merc @ WOT will charge up to 20 volts, thats why it is so inportant to keep all wires clean and in good cond. And the Batt secured to the floor,throw away those wing nuts on it to and use nylocks, bouncing cables will loosen up the terminal ends and cause a ele. spike's and short out charging systems,switch boxes, fuel gauge's,etc

By the way thats a great PIC of that boat!

I keep the battery secured to the floor, but it's in a battery box. Think I should take it out and strap it down to insure no movement?

I have not had any problem with those ss wing nuts loosening. Just the opposite, it pretty much it all I can do to get them lose! But go to nyloks anyways ya think? That would mean I'd have to start carrying tools! Guess I need to do that anyways eh?

I use wingnuts on the battery terminals on my Challenger which is probably an equal or rougher riding hull compared to your Cat and ive never had one even remotely come close to loosening up...and we beat the living snot out of that boat(see avatar for example)! I wouldnt worry one bit about it. I have, on the other hand, broken two battery tie downs from beating on it so much!

As for the box, I like em...makes a cleaner appearance and gives your battery a little bit of extra protection.

Cool. Thanks man.

My new oem solenoid should be in today, and I ordered a brand new voltage regulator, per Doc Frankenmerc's suggestion. NAPA had them in their Sierra line, so got one coming out of Syracuse, should be here today or tomorrow.

Winter projects are painting the rear bench seat, painting the front compartment door, getting ss hardware to install the door, and getting ready for a repaint of the deck come spring. Got some cracks that are gonna need to be ground out, kitty haired and faired first, then give this deck paint another try. It sure didn't work out too good this year!

I'd like to get a cover pretty soon for the boat. Motor will be removed and stored inside. Next year I want to get new aluminum wheels and radial trailer tires, and some of those boat guide-ons to install some big LED lights I got. My trailer needs some touch up too. Sheeesh, it's always sumpin!

Frank

frank you may have already done this,but the 1st thing i do is clean up all of the electrical connections,usually i find a bad ground connection,especially on trailer lights,but thats what i check 1st,john

John, I did all that sort of stuff this spring. Wiring is a specialty of mine buddy. Same with the solenoid. I rewired anything that I could, and added grounds. On all my grounds I use star washers too. I am very ground sensitive. I run grounds to all my lights on trailers. It's very rare for a trailer Frank did to have screwy lights, trust me. I would just as soon put new stuff on and go from there anyways.

New solenoid arrived while I was typing this!

Frank