MajBach
Chief Petty Officer
- Joined
- Jun 21, 2003
- Messages
- 564
Need some advice here. I have a 90 hp Honda (16 amp alt) and use it to charge both my marine battery and my deep cycle. The batteries are separated with an isolator switch. Additionally, the trolling motor is hooked up directly to the deep cycle - in other words - although the OB can charge the deep cycle and all electronics can run off of it, the trolling motor cannot draw from the marine battery (just the deep cycle) even when the isolator is on both (I think).<br />Anyway, I am wondering if my deep cycle is ready for the recycling plant its 4 years old. I have noticed the trolling motor doesnt seem to last very long nor run at a rate that I would expect from a 50 lb thrust. What I have observed though is that the deep cycle shows a full charge when I press the charge button on the trolling motor or the battery button on my front panel (both are used to check the charge state). The trolling motor defiantly shows signs of becoming weak after say an 30 min of intermittent use. The weird thing is, of I check the charge state say within a minute or so of using it, it may show 25 or 50 %, but if I come back and check it in 5 minutes, it shows 100%. <br />Another observation is the voltage from the OB. I have a voltmeter on my sonar and on the dash and both cross-check the same. When I am at idle, the system voltage is as follows (this is after both batteries have had extensive time charging while underway)<br /> <br />Isolator switch set to marine battery: 14.00 + V<br />Isolator switch set to deep cycle battery: 13.6 V<br />Isolator switch set to both batteries: 13.8 + V<br />Gets interesting here:<br />As I increase the throttle of the OB:<br />Isolator switch set to Marine battery 14.1 + V<br />Isolator switch set to deep cycle battery: as low as 12. V (shows a steady decline as throttle increases).<br />Isolator switch set to both battery: same as above but slightly higher voltage.<br /><br />I have also noticed that if the isolator is left on the deep cycle and I continue to run at cruise, voltage will increase, perhaps as high as 13.4 V, but I also notice the dash needle is shaky, like not a contestant voltage.<br />Any thoughts? Do I need a new deep cycle?<br /><br />One other quickie. I am using a fairly thin gauge for wiring - well not ideal. The gauge for the wiring running from the deep cycle to the trolling motor is about the same thickness or less as the wires that come from the OB ( I think this is 8 or 6 awg). This length of wire to the trolling motor is about 8 feet. The wiring running from the isolator switch (essentially the OB) to the deep cycle is about the same length but a little thinner. I thought this to be okay as I know that charging a deep cycle slowly is a little more preferable so I assumed the thinner gauge wire will allow for a corresponding decrease in voltage. <br />What I would like to know is, would it be beneficial to double up the wires running from the deep cycle to the trolling motor? I dont want to buy thicker wire right now but the boat did come equipped with two pairs of trolling motor wires and only one is in use.<br />Oh yeah, one more observation. If I have the isolator set to deep cycle and I use the trim - even if I am WOT - the system voltage drops to almost zero; sometimes enough to make the sonar shut off. This happens no matter what state of charge the deep cycle is at. I do not recall this happening last season.<br />Thanks a million!<br />MajBach
