Charging Woes

[Bill Balme]

My charging woes continue... A new observation has me baffled...

I have a 1000AH house bank and Group 27 engine start. There's a Blue Seas gizmo that charges the start battery once the charging voltage exceeds 13.4V.

My first problem is that the charging current rarely gets to 13.4V unless plugged into a dock. Therefore I have to charge the start battery by cross connecting house with start battery.

When I do that, my charging current (as displayed on a Blues Seas Vessel Monitoring System) drops from about 50A to under 20A.

Additionally - and this may be unrelated - if my 5.5kw generator is running and I decide to start the boat's engine, the generator quits...

I suffered a lightning strike 18 months ago - wondering if something is shorting out in some way. Any thoughts? or is this all normal?

[sailorboy1]

You have a big bank, maybe the alternator just can not get the voltage up to that high with the given state of charge.

Where does the alternator sense the battery voltage? Is it at the alternator (like most so it always is low) or at the batteries themselves.

What is the generator quitting on? Is it using the start start battery as the engine?

[Suijin]

I was thinking you should just contact Outbound until I read "lightning strike".

You're asking if this is normal...have you owned the boat since new, or if not, has it always behaved this way since you bought it? Were you the owner during the lightning strike? What repairs were performed after the strike?

And no, none of that is "normal". Your combiner should kick in and combine your start realistically, earlier than that, however you have a fairly massive house bank and I suppose it's possible that you never/rarely get it to the combine threshold. Do you have any aux charging like solar/wind?

The generator issue sounds lightning related but I dunno enough about that stuff to be helpful.

[smac999]

How big is your alt? With a small alt (under 80). It might take an hour plus to hit 13.4 with a bigs low house bank. the engine battery will last a long time running an engine so it's not a big deal. Though the charging should not drop if manually combined in that case. .

If you ran the alt to engine bank first it would be even worse as then you get acr cycling.

Make sure the alt wiring is big enough. Get an external reg with battery sense directly on house battery and connect alt to house bank direct to bank with fuse.

With a bank that big you should have a 150-200a alt with external reg.

The gen is a different issue and shouldn'5 be happening

[tkeithlu]

I agree with the general picture above; it's similar to my set of seven size 27s as a house bank and one 27 each for the starters on the engine and genset. Ordinary one-wire Delcos charge the two starters, but a similar 80 amp alternator on the other side of the engine would not charge the house bank, which sounds surprising, given it's 80 amps, but true. I went to a sophisticated Balmar 120 amp alternator/programmable regulator for the house batteries - it can both charge the house bank and take care of the batteries the same way the battery charger (shore power or genset) does.

[Teknishn]

The yacht I have been restoring for the past 5 years on-and-off (not mine BTW) has a 1200 Ah house bank. We've replaced the house bank twice in those 5 years. A year and a half ago I took over the duties as the yacht's engineer and learned that there was very little technical documentation for technical equipment onboard (nor schematics, hydraulic or piping diagrams...it was a nightmare). It was scary at first, let me tell you.

We were suffering from high battery failure rates...literally boiling batteries at times. The Victron Energy chargers (we have 2, alternating each day), we were being told by everyone were at fault. Spoke with the previous engineer who had had the same problem so he bumped up the charging rates on the chargers. Finally found the technical manual for the chargers online (for free...why couldn't someone else have done this?) and found that our chargers are only designed to charge battery banks up to 400 Ah, so the chargers were already working overtime.

Our batteries are 12-VDC group 27's wired in series-parallel to provide 24-VDC BTW. What I found was that if one battery went a bit wonky on us, the charger would continue to try and charge the entire system (overcharging already fully charged batteries) which resulted in damage to numerous batteries in the house bank.

So, with all of that being said, look to make sure your Blue Seas "thingy", as you called it, is rated for charging a battery bank that large. One weak battery may not allow your bank to get above 13.4 VDC and may cause subsequently cause premature damage to the other batteries in the bank. If you are not confident in troubleshooting this yourself, find a qualified marine electrician to sort this out for you (Not advertising myself here...currently in BFE, literally. Please feel free to stop by though! LOL). For CFer's I'll prolly do repairs for just a couple of quality beers!

Good Luck!

[westwinds]

I had a look at Blue Seas products. These appear to have some integrated circuits because of the intelligence built into their relays for disconnecting batteries from each other when voltage is low. https://www.bluesea.com/products/cat...harging_Relays You said you had a lightning strike. I think this has destroyed your Blue Seas relay. A lightning strike consists of a very high current that happens so quickly that you are dealing with radio frequencies. This creates an electromagnetic pulse that will cause current to flow in items not electrically connected together with voltages high enough to destroy integrated circuits. What is confusing for a trouble shooting endeavor is an integrated circuit can be weakened, but will not fail for a month or so. So if you have a radio, or a Blue Seas relay, it could fail months after the lightning strike.

There's something called surface effect where the current all moves to the surface of the conductor at radio frequencies. That's why you can have pin holes all around the hull at water surface level. Fiberglass can absorb water and this turns to steam with a strike which can cause all sorts of problems if the mast is not properly grounded to the water. Any wiring for lightning should not have a radius greater than found on a coffee can. What I am saying is take a careful look at your hull for fiberglass integrity. Many times lightning will come down the forestay into the anchor storage compartment and from there into the hull so double check that area. Also, ball bearings in the transmission can fail after a while so check for smooth rotation of propeller shaft.

[Paul L]

Bill
The first issue is to figure out why you are not charging at >13.4v. You aren't going to bring that big bank to a full charge without it. In addition prolonged under charging is going to kill the bank. You have at least 3, maybe 4 charging sources. Genset, shore power, alternator and maybe solar. Do they all fail to charge at 13.4+?

[Pizzazz]

It sounds very much like you have a malfunctioning battery that is bringing the whole bank down. I would split the bank and check then charge each battery individually first. May be this would help you track down the problem.

Once I had a similar problem, four golf cart batteries wired in series parallel were giving me intermittent low voltages. It turned out two of the batteries each had one cell dead and this was bringing down the other two plus killing the starter battery. Test and charge each battery individually, it should not be that hard to rewire them temporarily.

[westwinds]

Originally Posted by Pizzazz

It sounds very much like you have a malfunctioning battery that is bringing the whole bank down...

Yes, a shorted cell could keep charging voltage too low. Buy a hydrometer for lead acid batteries and use it to test each cell. You take the cap off each cell, there will be six for a 12 volt battery, and you suck some of the battery liquid into the hydrometer, tap it to get rid of any bubbles sticking to the float and take a reading. This a a very good way to get a state of charge (fully charged to dead) for each cell and a good way to determine the health of a battery. As a battery ages, some of the active material, lead oxide, falls off the plates into the bottom of the battery. This material takes up some of the sulfuric acid in the battery and gives a lower hydrometer reading than the rest of the cells. Also, the buildup of the material in the bottom of the battery will eventually reach the bottom of the plates and short positive and negative plates resulting in a completely dead cell.

By the way, be careful not to get any of the liquid from the battery onto anything because if is about one third sulfuric acid. It really eats holes in clothes and stings the hands if not washed off. I just use a plastic container to put the hydrometer into to keep everything under control while going from cell to cell. When taking a cell reading, leave the little hose like tip in the cell, take the visual reading and then gently squeeze the bulb to get the liquid back into its cell.

[Bill Balme]

Thanks for the responses.
I think my non green charging sources are simply inadequate. 60A charger on the generator, 100A alternator on the engine.
My generator used to power a 50A charger - and I was able to run watermaker and charger together - the extra 10A put me over the limit and I can no longer do that, so I should probably buy the biggest charger I can find for the generator...
Even so, I'm not sure why I can't get the voltage up...
We've recently arrived in the Caribbean and the warm water is placing heavier loads on the fridge and freezer, so my energy balance has probably gone way off.

[Bleemus]

Test your batteries. Until you do that everything else is speculation.

[sailorboy1]

Originally Posted by Bill Balme

Even so, I'm not sure why I can't get the voltage up...

the voltage isn't going to go up till the batteries are closer to being charged

[smac999]

You should have a 200a charger but you will need a 5k+ gen. as this will draw 30a just charger.

Everything Needs to be balanced.

Run the engine and gen together for ~4 hours and see if you can get the voltage up. That will give you 160a

You should have a battery monitor to watch net charge amps and ah

[smac999]

Even so, I'm not sure why I can't get the voltage up...
We've recently arrived in the Caribbean and the warm water is placing heavier loads on the fridge and freezer, so my energy balance has probably gone way off.

If your 1000ah bank is 50% de pleated, and you are charging from a 100a internal reg alt. You'd need about 10 hours of running to get them near full.

Go find a dock and plug in for 24 hours. Maybe longer if you are under 50%.