House Bank Replacement

[Black Diamond]

I need to get some new batteries, but largely because my bow thruster is becoming anemic. The house bank serves the living workload fairly well, but the draw from the thruster is apparently too much and it dies after about 4-5 thrusts (usually on a very windy day while backing in the boat to its slip).

The current configuration is that I have 4 Lifeline AGM 8D batteries in my house bank supporting the bow thruster and the house load. I have a Xantrex 2.0 inverter/charger, a 160AMP Ballmar alternator, the standard yanmar alternator for a 75HP turbo diesel, the MC610 regulator, and the XANTREX XBM battery monitor. I'm very comfortable with the charging system and feel its more than adequate.

None of the four are isolated, and therefore there could be one bad battery that is bringing down the whole bank. Its coming up on six seasons, however, and the coding on the battery says 2006. This is about the service life you can expect. 5-7 years.

I have 3 other batteries (starting bank, generator) but they are not relevant to this conversation as they seem to be fine and can be isolated from the house load.

I have several questions or requests for advice:

1. Does anyone have an opinion on LIFELINE vs any other type of battery in this situation? If I have to replace 4 batteries, I'd like to be comfortable with the decision and brand for the next 6 years.
2. Has anyone got a recommendation on a better battery monitor than the XBM?
3. I have someone recommending that it be possible for each battery to be isolated. That way if one battery goes bad, you can remove it from the bank so it does not drag down the others. Has anyone done this?
4. The batteries are in different spots on the boat. Two are at the base of the companionway amidships, one in the aft cabin under the berth and the fourth in the bow by the thruster itself. I'm worried about voltage drop due to distance by the monitor and the charging system. In other words, is there anything special in terms of monitoring to be done with that kind of setup?

I'm interested in your opinions.

Rick
Hylas 49-057 "Black Diamond"
Portsmouth, RI.

[donradcliffe]

If you spent the last 5 years plugged into the dock, your batteries may still have a lot of life left in them.

When you say that your house bank consists of 4 batteries in separate places, how heavy are the cables which connect them together?? If the cables are at least 1/0, your bow thruster should be getting pretty good power from all the batteries, plus from the the alternator. If the cables are too small, then it is getting most of its power from the forward battery, which may indeed be getting weak.

Measure the voltage across the terminal posts of each battery when at rest (no load, no charging source). They should all read the same with a digital voltmeter. Then turn on a steady load of at least 10 amps for an hour and repeat. Then do the same measurements with the motor running and the thruster on, plus measuring the voltage at the thruster. That will tell a lot about what your problem is and where it is.

As far as battery type and brands, tell us what your plans are--living on the hook, weekend cruising, or daysailing. There is a wide range of feedback from Lifeline users, depending on how they use their electrical systems.

[Black Diamond]

OK... a few points...

When you say that your house bank consists of 4 batteries in separate places, how heavy are the cables which connect them together?? If the cables are at least 1/0, your bow thruster should be getting pretty good power from all the batteries, plus from the the alternator. If the cables are too small, then it is getting most of its power from the forward battery, which may indeed be getting weak.

* They are probably 1/0 but I admit to not having checked specifically. They are god awful big with heavy shunts at the thruster end and a 400amp bussman fuse. I can check that.

Measure the voltage across the terminal posts of each battery when at rest (no load, no charging source). They should all read the same with a digital voltmeter. Then turn on a steady load of at least 10 amps for an hour and repeat. Then do the same measurements with the motor running and the thruster on, plus measuring the voltage at the thruster. That will tell a lot about what your problem is and where it is.

* I've also done this, but I honestly cannot remember the exact voltages. As I recall even a small fraction of a volt can be a big deal, so let me get the exact figures before posting.

As far as battery type and brands, tell us what your plans are--living on the hook, weekend cruising, or daysailing. There is a wide range of feedback from Lifeline users, depending on how they use their electrical systems.

* This I can answer. We keep the boat at a dock for a New England season and its taken out each November. The batteries are disconnected for the winter and then hooked up to a charging source in the spring. I admit to not having trickle charged them over the winter. Our cruising is largely coastal cruising for up to 3 weeks at a time, during which the battery monitor is really important. We have a Panda mini-8 which can throw over 100 amps into the batteries when needed and (as I said) I am happy with the charging system. We usually anchor out, with an occasional mooring ball where not allowed. We are always in the water early, say the first week in April. I have LED lights for below decks, the usual Microwave and TV stuff. I HAVE A COLLEGE AGED DAUGHTER who likes to keep lights and fans and other things on and this is a constant battle. I keep a wireless network on the boat for our three notebook PCs and broadband card. This is AC powered by the inverter. We are religious about turning it off when not needed. For electronics, the biggest draw is the radar (4KW) / chartplotter, which I use even in good weather.

I like the idea of zero maintenance. I've always had AGM's. My other batteries are AGM's so I'm not sure about mixing chemistry/construction on the same charging source.

Hope this helps..

Rick
Hylas 49-057
"Black Diamond"
Portsmouth, RI

[Hud3]

Try equalizing the batteries before giving up on them.

Here's what Lifeline says...

Conditioning/Equalizing Charge: 15.5 volts for 8 hours

Conditioning/equalizing should only be done when the battery is showing symptoms of capacity loss. If conditioning/equalizing is necessary, first go through the normal charge cycle. Once the battery is as fully charged as possible, start the conditioning/equalizing charge.

Source: Lifeline Batteries - Marine & RV Deep Cycle Batteries

[GordMay]

Because a Bow Thruster typically operates at a high current, low duty cycle (duration), I’d expect most manufacturers would specify an SLI (Starting) type battery (rather than Deep Cycle), with a very high MCA (Marine Cranking Amps) rating. The thruster operation is more analogous to a starter motor, than to a domestic house load.

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[David M]

Use a clamp ammeter to measure the amount of current that is running up to the battery closest to the bow thruster. The more of a recharge current you are getting to that battery after using the bow thruster, then the better. I agree that you want some good sized cables leading to the bow thruster battery so that the load is shared more equally amongst the batteries.

[CarlF]

The conditioning cycle may help but at six years you're running out of time. Some folks I know just replace at 5 years figuring it's just not worth the risk of a failure during the sailing season. Since I assume the boat's out of the water, you can also now wait until spring and buy fresh batteries and have time to shop around.

Lifeline seems to have gotten more emphatic about conditioning/equalizing. As far as I know they are the only AGM that does this. Main Sail (who doesn't like AGM's much) posted this from Lifeline:


#1 Fully charge after each discharge. Estimated life: 6-9 Years

#2 Fully Recharge at least once a week and equalize once a month. Estimated life: 4-6 Years..

#3 Only recharge to 85% and equalize once a month. Estimated life: 2-4 years.

#4 Only charge to 85% and never equalize. Estimated life: 1 year.

Carl

[Hyprdrv]

Rick,
It's also not a good idea to leave the batteries without a trickle charge. The cold up there will pull the life out of the batteries and leaving them low for an extended time will shorten the life. I'm surprised they lasted this long. Lifeline = good.

Steve in Solomons MD
Lagoon 410SE

[Black Diamond]

All good thoughts

I have had Andrew from lifeline on the phone with me walking thru the equalization and is-it-getting-enough-charge checks

At this point I'll sum up what I've heard

1. It's probably time to replace
2. No complaints against lifeline but not much in alternatives
3. Make sure of charge and connections (including trickle charge over winter)
4. No real opinions on monitors

That about it?

Rick

[matauwhi]

G'day, Mate. My Lifeline AGM 8-Ds are going on 14 years old and still going strong. I will replace them with the same if I ever need to!! I'm using a 130 amp Heart Charger and Link 2000 monitor. I also have a bow thruster.

If I read your post right, your bow thruster is hooked to your house batteries which are isolated from your starting battery. I have my bow thruster wired to the starting battery. Normally, if I need the bow thruster, I have the engine running. My 100 amp alternator assists the drain on the 8-D battery that I have in this service and the system voltage is around 14 volts giving you a bnost in bow thruster performance. You might want to look at rewiring you bow thruster to your starting battery.

You might have to compromise a bit when you do this. With the bow thruster up foward and the engine aft, you are going to have some longer battery cable leads to service on or the other. I was able to locate my starting battery about in the middle and have never had any issues with voltage drop causing a issues with starting the engine or bow thruster performance.

All the best. Cheers.

[Lancerbye]

Originally Posted by matauwhi

G'day, Mate. My Lifeline AGM 8-Ds are going on 14 years old and still going strong. I will replace them with the same if I ever need to!! I'm using a 130 amp Heart Charger and Link 2000 monitor. I also have a bow thruster.

If I read your post right, your bow thruster is hooked to your house batteries which are isolated from your starting battery. I have my bow thruster wired to the starting battery. Normally, if I need the bow thruster, I have the engine running. My 100 amp alternator assists the drain on the 8-D battery that I have in this service and the system voltage is around 14 volts giving you a bnost in bow thruster performance. You might want to look at rewiring you bow thruster to your starting battery.

You might have to compromise a bit when you do this. With the bow thruster up foward and the engine aft, you are going to have some longer battery cable leads to service on or the other. I was able to locate my starting battery about in the middle and have never had any issues with voltage drop causing a issues with starting the engine or bow thruster performance.

All the best. Cheers.

+1 That is the way miine is set up. Very old Gel house batteries and 6 year old Golf cart type starting batteries. Lots of power on the bow thruster powered by the start batteries.

[Black Diamond]

Interesting. I can understand a starting battery perhaps being able to handle a high draw for short periods better than a deep cycle, but what I don't understand is the engine comment. If your alternator charges the house bank as well as the starting battery, would it make that big a difference?

Rick
Hylas 49-057 S/V Black Diamond
Portsmouth, RI

[matauwhi]

G'day, Rick. I have an isolation relay on my engine alternator than I can manually engage to remove the house bank batteries during bow thruster or windlass operations. Hope that answers your question. Cheers.