12-14V across batteries, but system reads low

[topherbd16]

I get 12-14V across both of my batteries and after turning on the system, engines off, I get the low battery warning at 8-10V either instantly or Up to a minute later. When I turn the emergency parallel on the system voltages go to 12-13V. I’m able to start the engines with 8V as the system reads and warning going off, but believe actual voltage may be higher as my voltmeter showed.

i shot a video of what’s going on.

Any advice? Other than to dust the console?

 

[redthumper9]

My first guess is that you need to do the mod to fix your voltage readings if you haven't done so. I'm thinking that one of your batteries is toast and when you switch to emergency parallel, it's basically reading the good battery.?? Maybe someone else will chime in......

https://jetboaters.net/threads/fix-for-connext-battery-voltage-issue-confirmed.11381/

 

[motomandan]

I get 12-14V across both of my batteries and after turning on the system, engines off, I get the low battery warning at 8-10V either instantly or Up to a minute later. When I turn the emergency parallel on the system voltages go to 12-13V. I’m able to start the engines with 8V as the system reads and warning going off, but believe actual voltage may be higher as my voltmeter showed.

i shot a video of what’s going on.

Any advice? Other than to dust the console?

Batteries are shot! Marine Battery Maintenance 101 - e Marine Systems

 

[Dixemon]

Check the electrolyte level in your batteries, fill as needed with distilled water, charge and if you still have an issue you may have cooked a cell. In which case you will need a new one.
If electrolyte level is good, and it won't take a charge you will need a new battery.

 

[topherbd16]

My first guess is that you need to do the mod to fix your voltage readings if you haven't done so. I'm thinking that one of your batteries is toast and when you switch to emergency parallel, it's basically reading the good battery.?? Maybe someone else will chime in......

https://jetboaters.net/threads/fix-for-connext-battery-voltage-issue-confirmed.11381/

Thank you! Going to confirm this wiring mod and see what it does. Will also take batteries to a parts store and have them load tested.

 

[ripler]

Did you check the voltage at the batteries after you turned your key on? Even a battery that is shot can show 12V and until you put a load on it.

After reading through the above posted mod, I am convinced Yamaha engineers are idiots. It's a shame that consumers have to come up with solutions to problems that Yamaha should have caught.

 

[Julian]

I get 12-14V across both of my batteries and after turning on the system, engines off, I get the low battery warning at 8-10V either instantly or Up to a minute later. When I turn the emergency parallel on the system voltages go to 12-13V. I’m able to start the engines with 8V as the system reads and warning going off, but believe actual voltage may be higher as my voltmeter showed.

i shot a video of what’s going on.

Any advice? Other than to dust the console?

Your house battery looks to be dead.....11.7 is less than 30% charged. The fact that it drops to 9 or 10v suggests it is VERY dead and that 11.7 is just the surface charge.

 

[Julian]

Here is a voltage chart for reference:

 

[Cambo]

Check the electrolyte level in your batteries, fill as needed with distilled water, charge and if you still have an issue you may have cooked a cell. In which case you will need a new one.
If electrolyte level is good, and it won't take a charge you will need a new battery.

No load 11.7 is a dead battery or needs a charge. As stated above check the electrolyte get a charger you will need one if you have an upgraded stereo the statetors are not good for a deep charge cars have alternators these boats have stators. Charge it bring to an auto parts store they can do a load test be careful low electrolyte produces flammable hydorgen gasses a spark from the cables can cause the battery to blow. It happened to a friend while he went to jump my car the battery lid blew off into his face luckily no lasting injuries.

Random videos

 

[topherbd16]

Yes, I agree the house battery may be bad... may be both... will get them load checked after I get back from vacation before I attempt touching any wiring. I checked water levels in batteries and both were fine. And I also agree the aftermarket amp added may be helping to kill the house battery sooner.

I will also trickle charge them when not in use. Can you trickle charge both with one charger (w/ yellow switch in parallel?) or should I have two separate chargers? I'm not an electrical guru... as you have now found out.

 

[topherbd16]

Actually, I see several articles, videos and diagrams on charging two 12v batteries w/ a single charger... looks like there are several options. Some good, some completely bad.

 

[redthumper9]

Actually, I see several articles, videos and diagrams on charging two 12v batteries w/ a single charger... looks like there are several options. Some good, some completely bad.

I've done it this way for years.

 

[ripler]

Yes, I agree the house battery may be bad... may be both... will get them load checked after I get back from vacation before I attempt touching any wiring. I checked water levels in batteries and both were fine. And I also agree the aftermarket amp added may be helping to kill the house battery sooner.

I will also trickle charge them when not in use. Can you trickle charge both with one charger (w/ yellow switch in parallel?) or should I have two separate chargers? I'm not an electrical guru... as you have now found out.

Best practice for charging batteries is to charge them individually. If you put the batteries in parallel you are essentially creating 1 big battery. Battery chargers are designed to sense the battery voltage and change the charging accordingly, so you could have a battery that needs charged and a battery that is fully charged and the charger will sense the fully charged battery and quit charging. The best way to do it is use 2 chargers or a dual bank charger and to make sure your batteries aren't in combined mode.

 

[topherbd16]

Had a load test done and the house battery is toast like everyone suspected, starter battery is perfectly fine . I have Interstate G24 batteries but see a lot of chat about G31s...(especially the Duracell AGMs)
Will G31s fit an ‘18 212x? I’m sure anything is possible with modifications to wiring layout and straps, but is it fairly simple?

 

[motomandan]

DEKA AGM
You can buy the NAPA house brand it is a relabled DEKA. Very good batteries. I have a sailboat as well as my FSH210. Same DEKA AGM in the sailboat for 7 yrs. I do have a good 3 stage charger as well makes a huge difference in the battery lifespan. It has a diesel motor but rely heavily on the Batteries when sailing or anchored up for the night.

 

[anmut]

it's funny, my fully charged house battery ALWAYS says 12.4 in Connext and on Ride Steady. Brand new battery, always topped off, always reading 80% (according to that chart).

 

[redthumper9]

I use DEKA (Duracell) non AGM. Have for years and like their performance. An onboard charger is a must for a longer life span.

 

[topherbd16]

I upgraded from two G24 lead acid to two G31 Duracell AGMs. Had to reconfigure mounting and install a new battery tray for one of the G31s, but I will now feel much more confident running accessories, included added amps. Next step is an onboard dual bank charger for easy charging (storage has electrical). Thanks for the help all!

 

[Brian McIver]

I upgraded from two G24 lead acid to two G31 Duracell AGMs. Had to reconfigure mounting and install a new battery tray for one of the G31s, but I will now feel much more confident running accessories, included added amps. Next step is an onboard dual bank charger for easy charging (storage has electrical). Thanks for the help all!

Not that you asked my opinion on chargers, but I just put a 3 bank Minn Kota 318PC on board charger for my ‘17 212 Limited S to remedy the same low voltage problem after sitting at the sand bar all day. Works great and I understand the way it conditions the lead acid batteries should extend their life. Can I ask how you came to the decision to change to AGM batteries? I’m considering a 3rd battery for the stereo alone (couple amps, JLaudio speakers towers and subs) and I’d love to hear any opinions.

 

[topherbd16]

Not that you asked my opinion on chargers, but I just put a 3 bank Minn Kota 318PC on board charger for my ‘17 212 Limited S to remedy the same low voltage problem after sitting at the sand bar all day. Works great and I understand the way it conditions the lead acid batteries should extend their life. Can I ask how you came to the decision to change to AGM batteries? I’m considering a 3rd battery for the stereo alone (couple amps, JLaudio speakers towers and subs) and I’d love to hear any opinions.

I probably over thought it and may end up paying more per hour I get out of the batteries than lead acid, but who knows. I was convinced to go with AGM after reading this and knowing I'll get more cycles with a deeper draw than with a lead acid. Absorbent Glass Mat (AGM) Battery Information - Battery University

I also get a decent warranty at 30 months so I expect to get the next 3 summer for sure, otherwise replace with no questions asked.

I spent 8 hours Friday at Delaware lake (Delaware, OH) with the stereo on, running ballast pumps several times and voltage on Connext never dropped below 12.5V for SYS or AUX. The next morning, I put a Schumacker 1.5A smart charger on each and the start battery was fully charged in an hour. The house battery took about 4 hours.

The Interstate G24 lead acids weight 46 lbs.
Duracell G31 Deep Cycle AGMs are 67 lbs. each. Those were fun to mount. On board chargers are great to save the back for sure.