5 batteries one red.

[Hoohaa]

Originally Posted by Moontide

Not sure what you mean by "sit at 13.7" Fully charged should be around 12.7. Is 13.7 with a battery charger or alternator active?

Currently I use the boat most weekends and that is the level displayed when I return to the boat. It's charged with wind and solar.
It rarely gets below 11.8 volts during use.

[Hoohaa]

Originally Posted by SV__Grace

I recently encountered a similar situation with my AGM battery bank and while I'm no expert, I've learned a few things that I'll share.

Yes, definitely check the electrolyte levels on these batteries. Assuming that isn't the problem, next step is to check the voltage of each battery and to do so you must disconnect the batteries from each other and the boat. Then let them sit overnight, disconnected and test again. Great time to do maintenance such as cleaning, inspecting connections, etc. A battery that is bad or deteriorating will have lower voltage than the others and will typically lose more overnight than the others.

One bad battery can mess up the performance of your bank. Here's my experience of that:

Two years ago, to prepare for our current lifestyle as full time cruisers, we completed the refit of our boat, which included a battery bank of six high quality 6V Mastervolt AGMs. Total capacity 1200amh. Installed and recommended by our electrician, who is a wiz and I trust him.

Fast forward to earlier this year we were getting low voltage alarms going off when the battery monitor was showing 78%. It didn't make sense that our battery bank would be at 10.2 volts having used only 1/4 of capacity.

Testing as above found 1 battery testing lower voltage than the others. Following the instructions of my electrician I ended up disconnecting the battery pair with the suspect battery.

So now my battery bank is 800amh but performing as it should with no more low voltage alarms. I can go longer and use more battery capacity between charges, and the bank charges with the generator and reaches 100% much faster than before.

The bummer is that if one battery in a bank goes bad, the entire bank must be replaced. The good news is that the price of lithium batteries is going down and in a year or two we'll go that route.

Sounds similar but lucky for me I haven't had a real noticeable drop in performance yet.

[Hoohaa]

Originally Posted by hlev00

Not your question but something else to look into. There appears to be three grounds coming out of the box - two off the left end of the bank and one off the rightmost battery. There is only one positive coming off the bank. The multiple grounds might lead to a ground loop depending on where those all lead to. The two on the left might be okay if that post is acting as a branching point. The one on the right looks most suspicious. If it is in a circuit with a substantial amount of current, it is going to result in uneven battery usage.


The various gauges of wire in the bank at least make it difficult to assess if they are sized properly.

The extra wire is running to the two batteries.

[Hoohaa]

Originally Posted by Bill O

Have you ever added water to your batteries? Fairly certain those bigger panels do come up (need to gently pry them out) in those batteries. Kinda a misnomer that they are "maintenance free" since they aren't really sealed like an AGM. Sure they will last maybe 5 yrs before you need to replace them, but will last longer than 5 years if you add some water.

Never added water.
Have tried but It felt like I was going to break something so I gave up.
I might contact my dealer and see if it's possible.

[Jim Cate]

FWIW, I just bought a new start battery here in Oz, and it had a "magic eye" thingo on top, just as its predecessor did. Lasted around 6 years with zero maintenance, so not really complaining... but such batteries are indeed still sold, at least here in Tasmania.

Jim

[Hoohaa]

Originally Posted by Pete7

Certainly worth lifting them out and giving them a good clean including the terminals. If you can just route the wires so the pos and neg wires don't sit on top of each other that would be good too. You really don't want those rubbing together whilst you are sailing along.

Pete

Noted

[Hoohaa]

Originally Posted by Chotu

Yes. You need to disconnect the batteries to measure the voltages properly. Because they all affect each other in the bank.

Thanks

[S/V Illusion]

Originally Posted by Hoohaa

Never added water.
Have tried but It felt like I was going to break something so I gave up.
I might contact my dealer and see if it's possible.

It’s not only possible but essential maintenance. The removable cover plates are there for a reason.

[Hoohaa]

Originally Posted by S/V Illusion

It’s not only possible but essential maintenance. The removable cover plates are there for a reason.

I think they are sold as maintenance free.
But I would be happy to check the water levels If I could find a way of remove the cover without breaking it?
Any tips or link's?

[smac999]

those sealed maintenance free batteries have no place as a house battery on a boat...


maybe as a start battery.

[Aethelwulffe]

At 13.7 his charger must be on-line...or his voltimeter needs tweaking.
Disconnect, weigh or examine electrolite levels, test each battery *with a load checker*, then make decisions on condition. Voltimeter does not tell you much about the state of the battery, just the state of the charge. Load checkers often cost less than $20, and anyone with brains enough to operate a stove safely can use one. You should totally own one, period. If you don't, then someone on your dock dang well should.

After that you can worry about little stuff like rerouting/resizing your terminal jumpers and the like. What you have appears to be workable and fairly safe if it is all in an enclosed but ventilated/cooled box. Better to have no covers than have some fancy stuff with leads you can't properly torque. Paranoia however, is the key to survival.

[Hoohaa]

Update
I was on board today and had a look at the other 2 batteries in the bank (Bat 4 & 5)
Wouldn't you know it. Bat 4 is showing red as well. I checked the log. I purchased the batteries at the start of 2017, so that makes them almost 3 1/2 years old.

I phoned up the fellow I bought them from. Long storey short, that's about the lifespan.
So. I am know thinking of replacing the Bank with 5*6V, wetcelled 220 amp hour batteries.
(Lithium is too expensive for my needs atm.)
Reasons.
- Lifespan 3.5 to 5 years if I look after them.
- Reasonably priced.
- Increased amp hours 525 upto 880 AH
- The physical dimensions will be a better fit for my boat. If I build a slightly larger battery box, I can get 4 of them in there and the 5th would go under my chart table seat next the start battery.

Any opinions?

Regards Jeff.

[a64pilot]

Assuming your a 12V boat, 6V batteries need to be in pairs, odd numbers won’t work.
It takes two in series to make 12 V.

But flooded deep cycle “golf cart” batteries are a MUCH better battery most likely than what you have.

[Aethelwulffe]

I like those Trojan 6V batteries. Thing is, if you don't tend to draw down your battery bank to 30% and charge it back on a pretty regular basis, you have too large of a battery bank.
I am not saying that you shouldn't have *space* for a large battery bank, but I would buy two of those 6V for a "house bank", and then have an always isolated (never in parallel) 12V for starting/backup for your short excursion battery setup. If you really are dragging your battery bank(s) down to 30% on a regular basis, then you are getting value out of them, but if not, then you are throwing money in the head.
If you use a small bank of series-connected 6V now, then expand it later by adding two more 6V wired in series, you can and should separate them into different banks so as not to mix new with old. You can ALWAYS add a second (or third) battery selector switch and have as many nodes to your power supply as you like. A 3-4 bank charger and separate voltimeters is a good idea. You can always buy a very very inexpensive (like this: https://www.amazon.com/4-0-30v-Digit...fsclp_pl_dp_12 ) volt meter and switch that lets you just push a local momentary switch and read voltage directly on each bank. When you see voltage difference in two banks > .1 V, you know you should not use them in parallel (a "both" on battery selector switch) for anything more than a moment to do something like start the engine. You don't want one battery trying to charge the others!
-As was pointed out, there is not provision on a 12V boat to use five 6V. Personally, for boats with large battery consumption, hot charging and large battery banks, I switch everything on the boat to 24 or 48V. You can always tap off of a large bank to get 12V starting juice. 24V lets you use 1/2 the size wires for the same current, and you can transmit that power over much longer wires without voltage drop. The inverse is true. Those 6V connections need to be BIG for a given amperage. Your existing ones look fine, but you will need pairs of 6V series connected that are then connected in parallel. The series connections POS-to-NEG should be very short and very heavy.

[Sailmonkey]

Originally Posted by Hoohaa

Update
I was on board today and had a look at the other 2 batteries in the bank (Bat 4 & 5)
Wouldn't you know it. Bat 4 is showing red as well. I checked the log. I purchased the batteries at the start of 2017, so that makes them almost 3 1/2 years old.

I phoned up the fellow I bought them from. Long storey short, that's about the lifespan.
So. I am know thinking of replacing the Bank with 5*6V, wetcelled 220 amp hour batteries.
(Lithium is too expensive for my needs atm.)
Reasons.
- Lifespan 3.5 to 5 years if I look after them.
- Reasonably priced.
- Increased amp hours 525 upto 880 AH
- The physical dimensions will be a better fit for my boat. If I build a slightly larger battery box, I can get 4 of them in there and the 5th would go under my chart table seat next the start battery.

Any opinions?

Regards Jeff.

220ah 6v batteries, as previously stated, will need to be installed in series pairs. In other words, even numbers only.

Also, 4 220ah golf cart batteries won’t yield 880ah. You’ll get 440ah. Again this is from the requirement to wire the four batteries in series parallel to get 12 volts.

However 4 golf cart batteries will be infinitely better in every regard than those “maintenance free” things.