Could I have killed both batteries ?

[lenny2113]

Good day all,<br />I started the engine for the first time this season and here we go again : Did not notice that a positive battery cable is quietly resting on the alternator... The outcome was - lots of sparking and a damaged cable. I replaced cable and started engine. Now, a week later I could no longer start it as it was showing symptoms of dead battery. Both batteries are showing full charge and hold a load. I was able to start the engine when I jumped booster cables from the other engine. <br />Can my battery be shorted even though it is showing charge and load?<br />Thank you,<br />Happy, SAVE! boating season to ALL

 

[BrianS.]

Re: Could I have killed both batteries ?

Take it to a Auto Shop and have them check it for bad cells.

 

[Don S]

Re: Could I have killed both batteries ?

Take the batteries and have them load tested. That will tell you the story for sure.<br />But you may have blown the alternator, and now it's not charging.<br />Here is a quick test.<br />Take your test meter and put it on the battery and read the voltage. Then start the engine and rev it up to about 1500 rpm or so and check it again. What was your first and second readings?

 

[lenny2113]

Re: Could I have killed both batteries ?

Thanks for advice. I do have a load tester and it was reading "good". Also, when I started engine by jumping cables from the other engine, my volt gauge was reading about 13.5V. I will test with volt meter. <br /><br />What is the size of battery I should get for Merc 350 ? <br />Thank you!