Battery problem thoughts much appreciated!

[Three Sisters]

Originally Posted by Bermuda Forte

Following- ‘need to know what the OP finds and the solution.

Yes. Same here.

[Three Sisters]

Originally Posted by Ip485

I have hardly used my house batteries off shore power since the whole bank was replaced. The new batteries are Rolls - so should be of very good quality, and about 1 year old.

I find running the DC system off just the batteries the volts drop very quickly. For example at 75% charge the volts read 11.6V under a load of 30 amps, and fall away further. If the load is reduced, it doesnt make much different to the volts. The volts are measured on the main panel and also on a BMV-501. The position is similiar when the gauge is showing 100% charge albeit the volts are just a little higher. At 75% the AIS trips out due to low voltage.

As soon as the charger is switched on the volts recover almost immediately.

My feeling is there is a poor contact somewhere. Could this explain what I am seeing?

I should have checked where the BMV-501 is measuring the volts (I didnt install this). It would be interesting to know which side of the main DC switch it is, in case there are any poor contacts in the switch. I have a main rotary switch for the DC power, and a main DC swith on the panel.

I would be very interested if anyone has any thoughts please?

My only thoughts would be if you are interested in receiving any warranty work to keep a thorough log. This would include the AIS tripping off, voltage readings, temperatures and such.

You've afforded yourself the luxury of having the system installed professionally so my thoughts would be to continue the troubleshooting in the same manner with a professional survey. Good Luck ! And do let us know the outcome.

[kenbo]

Originally Posted by SailRocyPoint

Stu is 100% right..... check the grounds! he directed me (NYSail)
Good luck!

We don't have enough information to be so certain of this. Perhaps it's an isolated ground system with no engine ground..

[mitiempo]

Originally Posted by kenbo

We don't have enough information to be so certain of this. Perhaps it's an isolated ground system with no engine ground..

Grounds to loads and between batteries should certainly be checked, as well as all positive connections between batteries, to switch(es) and to loads.

Engine ground doesn't necessarily relate to the problem - it only would relate to engine starting and alternator output.

[Black Diamond]

I'm assuming you have checked the batteries? Most of the notes have talked about the charger, and those notes are perfectly reasonable, but you might want to see if your new batteries contained a lemon. If they are hooked together you could have a bad battery in the middle of the bank bringing them all down. You could test for this by isolating the batteries from the bank and testing them at rest. If lemon exists, it will show this way.

[Ip485]

I promised to report back for those who kindly contributed.

While the batteries have now yet to be removed it would seem the "professionals" who installed them believe one or more batteries have failed. I am not certain how they have reached that conclusion because I wasnt there at the time, but an hour and a half and lots of calculations resulted in that conclusion.

The next step is for all the batteries to come out.

I know that some will say be involved in the process and / or roll up your sleeves. However, while I am very happy to do so, the batteries were all supplied and fitted at considerable cost by professional marine electricians so as you can imagine I am reluctant to do what someone else has been paid to do.

No doubt more will come to light when the batteries are all out and the manufacturers have them back. The batteries are all Rolls AGMs.

[john61ct]

Cryin' shame.

I can certainly understand you not wanting to get in the middle of the labour side.

But IMO wrt the design, gear selection and installation process, professionals are paid to educate and advise me as the customer, and help me to make the decisions.

I would learn enough to check everything, test and verify, and understand how to monitor with trusted tools, accurate ammeter and DMM, so any future problems can be prevented.

IOW never just trust them to do it right any more than necessary, know enough to DIY even if you aren't actually going to.

[ZULU40]

Originally Posted by john61ct

know enough to DIY even if you aren't actually going to

kind of the rule of life on a boat ..

[Ip485]

John61ct - I could not agree more. I can turn my hand to most things and am pretty comfortable with electronics. That said, this thread has made me realise that there were some aspects of battery management that was fundamentally lacking; I am very grateful for certain of the explanations. Thank you all.

I remain interested to see when the batteries come out what the final conclusion is.

[a64pilot]

The only way they are gong to be able to determine the health of the batteries is by a capacity check, there is no other way.
I would become very proactive in the Warranty procedure, otherwise I’m betting your buying another set from the same folks.
I’d also bet that with respect, you murdered your bank, not intentionally of course, yet that is what happens to most banks, Achilles Heel of an AGM bank is they are very intolerant of abuse.

If you end up having to “eat” this, I strongly recommend that if you chose to remain with an AGM bank, you go with Lifeline. They no longer produce any battery that is not an AGM, it is their specialty.
I suspicion that while Rolls is an exceptional brand, the Cadillac of batteries if you will, that maybe they are having the AGM batteries built for them, and they may not be up to Rolls level of quality.
However that is just a suspicion.

[Sailmonkey]

A question that’s been nagging at me is this.

Why spend so much on a large battery bank for a boat that spends its whole life tied to shore power?

If you have cruising plans, and you’ve got a leave date 2-3 years in the future why not install a small bank sufficient for day sails, then 2-3 months before heading out purchase the cruising bank?

Otherwise it would seem to me your letting the clock expire on an expensive battery bank and not getting the benefit of using them.

[john61ct]

Originally Posted by a64pilot

while Rolls is an exceptional brand, the Cadillac of batteries if you will, that maybe they are having the AGM batteries built for them

They are definitely Chinese, I believe Full River.

While it would be better if the built their own local production facility, it is likely Rolls is imposing tight specs and rigorous QA verification processes to protect their reputation.

Just as Apple and hundreds of brand owners do to get top-notch results out of Chinese OEMs.

But we haven't get decades of real-life reports about longevity in real life conditions yet, just like Trojan's AGMs, we're relying on the company's reputation.

Besides Lifeline, Odyssey also is a stellar AGM vendor, and Northstar. Firefly Oasis for PSOC situations.

[a64pilot]

IP 485 is a pretty big boat, and I’d bet has a lot of modern conveniences, for a complex Boat that size an 800 AH bank isn’t all that large.
Heck I’m a 660 AH bank, and honestly wish I had 1000 AH.

[robert sailor]

Originally Posted by a64pilot

IP 485 is a pretty big boat, and I’d bet has a lot of modern conveniences, for a complex Boat that size an 800 AH bank isn’t all that large.
Heck I’m a 660 AH bank, and honestly wish I had 1000 AH.

The drawback to large battery banks in my opinion is being able to recharge them to 100% or close on an irregular basis. I much prefer a mid sized bank that I can recharge with solar everyday but that requires that your boat is very energy efficient.

[a64pilot]

I don’t see as long as your charge source is sized correctly that a larger bank would take more time to charge, mine takes over five hours and I have more charger than it will accept at my starting SOC.
Being often tied to shorepower is the textbook case for an AGM bank, you can partial charge once or twice during a weekend, then plug in and if your charger can be adjusted to end absorption based on acceptance amps, really get an honest 100% full charge.
His bank ought to last at least five years, and that is I believe pessimistic.
Efficiency often means doing without, and if I had a 485, I’m not doing without.
Sort of like I doubt people that have a Bentley worry about fuel mileage.