[Hemlock_SF]

I have a new to me 2005 Tiara 3800 with 7 West Marine gel batteries with a K5 Sticker on them so i am assuming 2015 battery year. Since the manual is missing the pages for the parallel wiring diagram i am guessing 3 for the house, 3 for the engines, and 1 for the inverter / charger? Anyway i found the charger wire for the engine group going into the C-Charger barely hanging in there and probably not charging very well for quite some time. I have re attached the charging wire and the 3 engine batteries do not seem to be coming back to life, they are currently sitting at about 6-8 volts after 10 hours of charging, all other batteries are sitting at 13.5 volts. So my dilemma is do i change out 3 gel batteries for $1500 or buy 7 new AGM batteries and a new charger for $2k? The C charger does not have an AGM setting but the C-charger alternator charger does. Any input would be greatly appreciated.

Also wondering if anybody has had issues with the battery monitoring not being accurate?

Actual battery voltage was around 6-8 volts 
3.5 volts on the meter
13.5 on the digital meter 

[hiccup]

I think you have a couple things going on.  

Based on your picture w/the Xantrex controller, it appears that you have the inverter option (which is really an inverter/charger combo).  In this case the C-Charger only charges the engine batteries and the inverter/charger charges the house batteries.  The Xantrex controller you're looking at is telling you the charging voltage for the HOUSE batteries only but not telling you at all what the engine charger is doing.

If the batteries are at 6-8 volts with the charger ON (C-Charger in this case), one of two things is likely happening.  Either the wiring between the charger and batteries is not electrically continuous or the charger is malfunctioning.  The most likely reasons for lack of electrical continuity would be the DC breaker switch under the stairs "Engine Charger" is OFF or the fuse in the C-Charger is blown.  Did you measure the charging voltage at the C-Charger with a multimeter?  What is the ammeter on the C-Charger reading?

As an aside, the inverter/charger likely can be reprogrammed to be compatible w/AGM batteries.  Furthermore, while Gel batteries are not compatible with AGM charging profiles (Gel batteries are very voltage sensitive), AGM batteries may very well be compatible w/Gel charging profiles--the key is to find out what the charging profile of the C-Charger is (ask Charles) and then compare that to the specs of the actual AGM batteries you're looking at.

[Hemlock_SF]

Thank you so much Hiccup!! This has been quite puzzle to figure out here and that info helps a lot. At the C-Charger I am getting 13.5 at both red wires. Based on this new information I am wondering if it’s the connections at the battery  . Pretty tough to get to with the other batteries in place but I may give that a go this afternoon. My second question would be, why are there no charging cables going to the engine bank (back 2 then 1 forward nd to the right)? I have pictures but it won’t let me upload any more. I will try and upload when I get back to my PC

[hiccup]

OK, that's a start. So you have 13.5v at the C-Charger but it isn't making it to the batteries.

Again, the most likely reason for this would be at the DC (not AC!) distribution panel--the breaker labeled "Engine Charger"--make sure it is on! Keep in mind there is an AC breaker for the battery charger (that's AC power to the charger) but there is also a DC breaker for the power from the charger. Both have to be on.

And the red wire from the charger isn't going to go directly to the battery. It will go from the charger to the aforementioned breaker and then likely to a distribution bus bar located near the back of the battery switches. It is here that the power from the charger would be attached to the main battery cable going to the engine battery bank.

So, next step is to check the breaker. If that is on I would get in the engine room and take off the back panel of the electrical distribution box. Note that this will expose live 120v connections so if you're not comfortable around high voltage then disconnect your shorepower first (although this makes troubleshooting more difficult).

Once that cover is off you should be able to probe the connections with a multimeter to determine where the disconnect is between the charger and the battery bank.

Hope this helps.

[Hemlock_SF]

The chase continues, pulled the panel and was probing the breakers, All was good there. Next I was checking the the engine, house and parallel switch. Engine had 13.5 going in and 3 coming out, after looking a little closer I noticed the parallel bar going to the engine switch had some burn marks on it. Turns out the parallel switch had shorted and melted the switch and the cable a little. The cable going out of the 3amp post of the switch went to a buss bar with 4 wires attached and all 4 wires were metering at 3 amps. Picking up the new switch and the cable in the morning and will try to put back in, it is a pain to get to those switches.

Thanks again for your help Hiccup

[MC1600]

I think you have a couple things going on.  

Based on your picture w/the Xantrex controller, it appears that you have the inverter option (which is really an inverter/charger combo).  In this case the C-Charger only charges the engine batteries and the inverter/charger charges the house batteries.  The Xantrex controller you're looking at is telling you the charging voltage for the HOUSE batteries only but not telling you at all what the engine charger is doing.

If the batteries are at 6-8 volts with the charger ON (C-Charger in this case), one of two things is likely happening.  Either the wiring between the charger and batteries is not electrically continuous or the charger is malfunctioning.  The most likely reasons for lack of electrical continuity would be the DC breaker switch under the stairs "Engine Charger" is OFF or the fuse in the C-Charger is blown.  Did you measure the charging voltage at the C-Charger with a multimeter?  What is the ammeter on the C-Charger reading?

As an aside, the inverter/charger likely can be reprogrammed to be compatible w/AGM batteries.  Furthermore, while Gel batteries are not compatible with AGM charging profiles (Gel batteries are very voltage sensitive), AGM batteries may very well be compatible w/Gel charging profiles--the key is to find out what the charging profile of the C-Charger is (ask Charles) and then compare that to the specs of the actual AGM batteries you're looking at.

Hiccup -- not to hijack this thread, but I think this is related...I have two original (1999) 50-amp Charles chargers that are gel-only (there's no switch on the back) and I desperately need new batteries.  I got an estimate to replace those chargers and add an inverter and was looking at $9000 BEFORE batteries!?  I want to at least make some progress on the issue. If I'm hearing you correctly above, do you think I could get away with just putting AGM batteries on these chargers?  If so, I presume I should change my regulators to reflect AGM?

[hiccup]

The chase continues, pulled the panel and was probing the breakers, All was good there. Next I was checking the the engine, house and parallel switch. Engine had 13.5 going in and 3 coming out, after looking a little closer I noticed the parallel bar going to the engine switch had some burn marks on it. Turns out the parallel switch had shorted and melted the switch and the cable a little. The cable going out of the 3amp post of the switch went to a buss bar with 4 wires attached  and all 4 wires were metering at 3 amps. Picking up the new switch and the cable in the morning and will try to put back in, it is a pain to get to those switches.

Thanks again for your help Hiccup

Good detective work.  It's a shame your surveyor didn't uncover this--should have been caught at survey for sure.

I also agree that the electrical distribution box is an embarrassing twisted mess of wires.  Tiara should be ashamed.

It sounds like you've got it covered from here.  As for your engine batteries, gel batteries are amazingly resilient to deep discharges (their strong point) so I would attempt to recharge them after getting everything fixed up again.  However, 6-8 volt resting voltage for an extended period doesn't bode well, even for gel batteries.  But make no mistake, these batteries didn't die a natural death, they were murdered.

---

Hiccup -- not to hijack this thread, but I think this is related...I have two original (1999) 50-amp Charles chargers that are gel-only (there's no switch on the back) and I desperately need new batteries.  I got an estimate to replace those chargers and add an inverter and was looking at $9000 BEFORE batteries!?  I want to at least make some progress on the issue. If I'm hearing you correctly above, do you think I could get away with just putting AGM batteries on these chargers?  If so, I presume I should change my regulators to reflect AGM?

You very well could find AGM batteries that are compatible with your 'gel' chargers.  To figure this out there are two main steps you must take:
1. Find out what the charging profile of the chargers is.  You could do this by contacting Charles and see if they know.  Alternatively you could actually measure the output of the charger with a multimeter.  You're looking for the initial voltage that they produce when they first come on, and then the final or 'float' voltage they switch to at some point.  Probably something like 14.2v & 13.6v.

2. Look at AGM batteries and find out their charging requirements.  Not all AGM batteries will have the same requirements.  The better batteries (i.e. more expensive, like Lifeline) will have thorough documentation and knowledgeable technical people that will have this info.

You may find an AGM battery that works with the charger.  Tiara went to a lot of trouble to make these boats compatible w/Gel batteries because Gel batteries were the best available.  AGM weren't really around/popular at that time.  Gel batteries are still better than AGM in terms of ability to recover after multiple deep discharges, but they are sensitive to overvoltage and expensive, so AGM is typically a better compromise.  Today if you want an expensive finicky solution that outperforms other battery types you go LiFePo4, but that's a whole other story.

[ReelMagic]

I own a 2003 38 Open w/6 GEL batteries (3 for the house and 3 for the engines; no inverter). They served me well and after 18 trouble free years I changed them to NAPPA 31 series GEL batteries. I considered changing to AMG's but was concerned with the  Charles Charing charging profile.. see attached.... Soo far so good after 2 years... M2C

[Hemlock_SF]

I own a 2003 38 Open w/6 GEL batteries (3 for the house and 3 for the engines; no inverter). They served me well and after 18 trouble free years I changed them to NAPPA 31 series GEL batteries. I considered changing to AMG's but was concerned with the  Charles Charing charging profile.. see attached.... Soo far so good after 2 years... M2C

I am currently only having issues with my engine bank which is charged with the C-Charger and they may come back to life after I get my wiring issues resolved. If they don't recover I will stick with the Gel Batteries and just replace the engine bank since the house batteries are fine and are charged with the Inverter / Charger I don't think it will be a problem mixing the new Napa batteries with the older Westnarine batteries.

Thanks for the info on the Napa Batteries, they are in stock locally and I can pick them up today if I need too

[hiccup]

From the Lifeline Technical Manual, the absorbtion charging voltage at 77°F should be 14.3±0.1v for their AGM batteries. You can see how different that number is compared to the graphic above. Often times people think AGM=AGM, Gel=Gel, etc. That is not the case.

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As far as getting 18 years from a set of batteries, that is truly amazing and shows how remarkable Gel performance can be when they're charged correctly (and likely they were not deeply discharged often and almost certainly never left deeply discharged for any period of time). I too would replace them with the same after getting 18 years out of the first set.