Battery combiner not working with low voltages

[simonpickard]

I've also been doing some tests to see when this issue kicks in.

Let the house bank drop to 12.45v and then ran the engine for 10mins this morning.

Saw the starter charge go right up to 14.5v pretty much straight away.

Never saw any charge going into the house bank.



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[Ex-Calif]

Originally Posted by simonpickard

I'm not sure I understand. So below 13v the combiner will never allow charge to the house bank? That makes no sense. I did run the engine for a good 30mins but saw no charge going into the house bank

Yes - Below 13v they won't combine.

Originally Posted by Sailmonkey

If there isn't a sense wire on the start battery then the combiner has no way of knowing that the start battery is receiving a charge......ergo it won't combine the house bank to receive said charge.

The positive from each bank is wired to the relay, the negatives are wireed to gether. That's how the relay knows the voltage on both sides.

Originally Posted by Jd1

Just because you turn on the engine, there is nothing saying that you will magically see over 13V at the battery. The state of charge of the battery determines that voltage. If the battery is discharged enough and the alternator is small(ish) then the battery will simply suck down the voltage supplied by the alternator.

If the alternator is wired into the start side the other issue is that you must measure the voltage on the relay post to negative. If the relay is not seeing 13v it won't parallel.

Originally Posted by simonpickard

But it does work most of the time. It's only when the house bank gets low. Say 12.1v. Then I can't get the house bank to charge.

The house won't charge from the alternator (if the alternator is wired on the start side) unless it sees 13v at the relay.

Originally Posted by Maine Sail

Connecting to start first is bass ackwards on vessels with large house banks that routinely get deeply cycled. This can cause the relays to cut in and out, in sand out until house bank voltage is finally high enough to remain latched.

<snip>

The only other issue could be in the neg for the relay or a fuse in one of the pos leads.. Be sure the neg is connected to the 86 terminal and has continuity to battery negs...

<snip>

Yandina and Blue Sea ACR's are perhaps the most reliable pieces of electrical gear I install.

1 - I don't disagree. I would wire all charge sources to the house side. The (usually) single start battery needs little charging - and even if it didn't get a charge for a while it can probably start teh engine 30 times before it's low voltage.

OTOH - I view the alternator on teh engine as a "momentary" charge source most of the time. You start the engine, motor for 15 minutes and shut down.

As opposed to solar and wind which are continuous charge sources. I can see a plan that puts alternator on the start side and all others on teh house side.

I am also with you on the Blue Seas ACR - Seems like a much simpler unit.

Originally Posted by smac999

sounds like you have an internal reg alt. and wired straight to engine battery. probably though starter post if all stock. no issue with this. if a small alt, under 80a I would leave it this way.

If your alt is not brining your engine battery up over 13v you have a problem with the alternator or wiring.

Yeah - with the engine running Simon needs to measure voltage on the relay post.

Originally Posted by simonpickard

I can always see over 14v on the starter. That has never been an issue so I don't think it's the alt.

If the alternator supply and sense wires are connected to the starter solenoid, and then there is a run to the positive bus, and then a run to the relay you have a lot of opportunity far bad altrernator sensing.

The alternator supply should go directly to the start battery or to the relay lug. The sense should also be wired the same - you don't want to sense 5 inches from teh alternator. You want to sense at the battery where it matters.

Originally Posted by simonpickard

I've also been doing some tests to see when this issue kicks in.

Let the house bank drop to 12.45v and then ran the engine for 10mins this morning.

Saw the starter charge go right up to 14.5v pretty much straight away.

Never saw any charge going into the house bank.

- If you measured the starter charge at the starter solenoid you need to measure the voltage at the relay. If there is 14v at the relay it should parallel in 4 seconds.

- I would also measure at the start battery terminal.

The other possibility - I haven't read your manual on this but the Blue Seas does this - is some units have battery protection logic. If there is a "big split" in bank voltages they won't parallel - this is to protect a failed/shorted bank from dragging down a good bank.

These units usually have a "force" function as an option - It is a switch that basically bypasses the relay.

[simonpickard]

Originally Posted by Ex-Calif

Yes - Below 13v they won't combine.



The positive from each bank is wired to the relay, the negatives are wireed to gether. That's how the relay knows the voltage on both sides.



If the alternator is wired into the start side the other issue is that you must measure the voltage on the relay post to negative. If the relay is not seeing 13v it won't parallel.



The house won't charge from the alternator (if the alternator is wired on the start side) unless it sees 13v at the relay.



1 - I don't disagree. I would wire all charge sources to the house side. The (usually) single start battery needs little charging - and even if it didn't get a charge for a while it can probably start teh engine 30 times before it's low voltage.

OTOH - I view the alternator on teh engine as a "momentary" charge source most of the time. You start the engine, motor for 15 minutes and shut down.

As opposed to solar and wind which are continuous charge sources. I can see a plan that puts alternator on the start side and all others on teh house side.

I am also with you on the Blue Seas ACR - Seems like a much simpler unit.



Yeah - with the engine running Simon needs to measure voltage on the relay post.



If the alternator supply and sense wires are connected to the starter solenoid, and then there is a run to the positive bus, and then a run to the relay you have a lot of opportunity far bad altrernator sensing.

The alternator supply should go directly to the start battery or to the relay lug. The sense should also be wired the same - you don't want to sense 5 inches from teh alternator. You want to sense at the battery where it matters.



- If you measured the starter charge at the starter solenoid you need to measure the voltage at the relay. If there is 14v at the relay it should parallel in 4 seconds.

- I would also measure at the start battery terminal.

The other possibility - I haven't read your manual on this but the Blue Seas does this - is some units have battery protection logic. If there is a "big split" in bank voltages they won't parallel - this is to protect a failed/shorted bank from dragging down a good bank.

These units usually have a "force" function as an option - It is a switch that basically bypasses the relay.

Below 13v it won't allow the house bank to charge? What is the logic in that? So I can only use say 10-15% of my house bank before I'm at a place where I can't charge the bank? Doing the ARC rally next week this is a real problem.

There is a switch but that doesn't work either. I was told it's a one way. Ie to allow the house to link to the starter and give it charge in case of the starter going flat.



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[simonpickard]

Just trying to get my head around this as I need a solution and quick.

1. Can I get a switch wired that bypasses the combiner completely? Get the house above 13v so it will work as normal. Any issues with this?

2. Re-wire so the Alt charges the house first. Is this a big job?

I still don't understand why I can't charge below 13v. That makes no sense to me at all but I need a solution here so I can use 50% of my house bank and not 10%.

Thanks for all the help so much, I really appreciate it.

Regards,
Simon



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[Ex-Calif]

Originally Posted by simonpickard

Just trying to get my head around this as I need a solution and quick.

1. Can I get a switch wired that bypasses the combiner completely? Get the house above 13v so it will work as normal. Any issues with this?

2. Re-wire so the Alt charges the house first. Is this a big job?

I still don't understand why I can't charge below 13v. That makes no sense to me at all but I need a solution here so I can use 50% of my house bank and not 10%.

Thanks for all the help so much, I really appreciate it.

Regards,
Simon



Please visit my blog:
www.sailing-interlude.com

You are misunderstanding the operations.

- Bank 1 (start bank) drops to 12.5 volts.
- Bank 2 (house) is at 12.75

The banks won't combine.

You start the engine - the alternator charges the start bank - when the voltage goes above 13.5v at the relay (which it should becuase the alternator is running) the relay will combine after 5 minutes because there is 13.5 volts on one side or the other.

The relay is measuring both sides. If there is 13.5v+ on the house side they will also combine in 5 minutes.

The relay is making sure there is "charge" voltage >13v on one side - or the other side - it doesn't care.

If your solar is on teh house side and producing >13v the banks will combine.

The key here - and the main test is the voltage at the post on the relay to ground.

One or the other side has to see >13v for the banks to combine.

So to recap - If the start side "and" the house side are <13v they won't combine.

If either side gets a "charge" voltage >13v they will combine. When they combine depends on how much charge voltage is available.

If you get >13.6v on either side they will combine in 4 seconds.

[Ex-Calif]

Oh - I don't know how your batteries are wired but...

If you have a 1-2-all switch you can just swtich to all and everything will be in parallel and the relay does not matter.

If you don't have a 1-2-all switch...

Take a look at this diagram. Your unit has facility for a momentary switch called start assist. Pressing this momentary switch latches the relay for 30 seconds.

The documentation says you can replace the momentary switch with a toggle switch and switch it "on" to force (and keep) the batteries in parallel.

(If you aren't shy about electricity you can take a piece of wire and temporarily "jumper" from any 12v supply to the connector on the back of the relay. You should see the batteries go in parallel immediately)

[simonpickard]

Ok, I have the start assist wired. When I get the issue (I.e. Starter battery is showing 14.5v under engine by house is not getting any charge) the start assist does not fix anything. I don't see the house then start to get charge.

You're saying that if either side (starter or house) is above 13v - which it always is as the starter always charges and shows 14.5v pretty much right away, it should work.

It doesn't.

To recap.

When the house bank is say 12.6 as it was this morning the alt never puts charge in. If the house bank is full and I start the battery I see charge going in.



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[Ex-Calif]

Originally Posted by simonpickard

Ok, I have the start assist wired. When I get the issue (I.e. Starter battery is showing 14.5v under engine by house is not getting any charge) the start assist does not fix anything. I don't see the house then start to get charge.

You're saying that if either side (starter or house) is above 13v - which it always is as the starter always charges and shows 14.5v pretty much right away, it should work.

It doesn't.

To recap.

When the house bank is say 12.6 as it was this morning the alt never puts charge in. If the house bank is full and I start the battery I see charge going in.



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www.sailing-interlude.com

You haven't told us where you are measuring the 14.5 volts...

Measure the votage between the relay lug on the start side and ground. If you are seeing 14.5 volts there I would say the relay is failed.

If you are measuring the 14.5 volts at the starter solenoid, 5 inches from the alternator, the troubleshooting is not complete.

PS - If you press and release the start assist they will only parallel for 30 seconds. You could I suppose hold the start assist down continuously.

[transmitterdan]

Simon,

Measure the voltage across the two big bolts on the relay when the engine is running and you have the start-bypass switch engaged. If you get anything approaching even 0.5V the combining relay is not working. Replace it with the Blue Seas ACR type of similar current rating.

You can also put a battery switch across the two bolted terminals of the combining relay. Then you can manually connect the two banks together. Open the switch when the engine is not running.

Whatever "electrician" you had look at this isn't very good in my view. I am sure you can find a good electrician that can sort this issue out in only a few minutes. All they need is a volt meter and do just a few simple checks to find which component isn't working.

[Maine Sail]

This is not something you need an electrician to trouble shoot. All you need is a volt meter (DVM)..

#1 There must be continuity between both battery banks on the negative side. Some boats have a negative switch to isolate house loads etc.. If both battery banks do not share a common ground then the relay will not work. This is simple stuff you need a complete circuit for the the current to flow...

#2 There must be continuity between the relay coils negative terminal and the battery banks. In other words the relays #86 terminal needs continuity to both battery banks.

#3 You may test & confirm for continuity but still have a bad connection that will pass enough current for a continuity test but not enough current to hold the relays coil energized or pass enough current from bank to bank. Ensure all connections are clean and in good shape.

#4 Voltage should be tested between each large stud of the relay and the #86 terminal with the Fast-On connector physically connected to it. You may need to slide it out a bit to get the probe on and confirm. This test ensures the relay itself is seeing a complete circuit, not just continuity between a large stud and a battery terminal.

#5 With the engine running you need to confirm that you have in excess of 13.0V between one of the large relay studs and the #86 terminal. If you do not it simply won't combine. This relay is bi-directional and bi-sensing. Voltage above 13.0V on either terminal will make it combine. Current flows BOTH directions through this product. It is NOT a diode...

#6 You need to confirm there is continuity between each bank and the relative studs for each bank on the relay. A blown fuse on one bank makes the circuit incomplete.

#7 You need to watch a connected DVM set to volts on the house bank side of the relay, from the moment the motor starts, and not take your eyes off it for at least a few minutes. I use my clamp Fluke set to capture in-rush amperage but a DVM set to voltage, and watched, achieves the same end result.

You may notice that you have a voltage increase and it then drops out. This is called relay cycling. Wayne Kelsoe, the CTO of Blue Sea Systems, wrote an excellent piece on this issue back in 2007 after numerous situations related to this. I had noted this numerous times in systems using combiners as far back as the early 2000's. The fix was easy, move the charge source to the house bank, problem solved..

Blue Sea Systems Relay Cycling


If you've completed all these steps and the relay still won't make, you have a bad relay... This would be extremely unlikely with a Blue Sea or Yandina Combiner but I can't speak to the reliability of the Cyrix...

[Derek Lumb]

Originally Posted by MBWhite

I'm with Uncle Bob here, at least until we get any additional information.

Also, the starting battery should always be charged first for 2 reasons-

First, as you may guess it is the more critical of the two. Being able to reliably start the main engine should be the first priority.

Second, the starting battery is usually a bit smaller in capacity than the house batteries, so it will take less time to charge up to where the overage can then go to the house. If it were the other way around it might take quite a bit of charging before you can begin to top off the starting battery. Which doesn't matter at all unless you only ever run the engine for 10 minutes at a time.

I am sorry but I disagree. It sounds good but makes no sense in practice for most boats. The engine start draws about 150amps for perhaps 10 seconds which works out to about 0.5ah. If it needs recharging urgently you have a bad battery problem. A starter battery is usually at least 70ah unless you go for a special like a Red Flash which is probably ~25ah. Either way you get a lot of starts before you need to recharge.

The house bank could easily be a half charged 300ah bank so needs 150ah of charge. If you connect to the starter battery your combiner will close on to the house bank which is likely to drag the charging voltage down to below the closing threshold - result the relay will open again, the voltage will recover and the relay close again - result relay chatter which does no good to anything, most of all the relay! That is why some system have the 10mins delay on them but it's not necessary if you prioritize the house bank. Then the house bank is charged for perhaps 20mins until the charging voltage rises to about 13.9v when it closes on to an almost fully charged starter battery (because you've only taken 0.5ah out of it), the voltage hardly changes and no relay chatter.

Much simpler in practice and less stressful on the charging components.

[Cadence]

Originally Posted by Ex-Calif

According to the manual there is a delay in connecting depending on the voltage of the battery.

http://www.victronenergy.com/upload/...N-NL-FR-ES.pdf

Below 13v the realy stays in dosconnect. 13-13.2 it delays 10 minutes.

Maybe the delay is what's got you messed up?

Are you sure you just don't have a marginal starting battery. Looking at Ex-Calif's post and the delay a marginal battery would seem to give that out come.

For what it may or not be worth?

[Cadence]

Originally Posted by Cadence

Are you sure you just don't have a marginal starting battery. Looking at Ex-Calif's post and the delay a marginal battery would seem to give that out come.

For what it may or not be worth?

I forgot to say load test the starter battery a volt meter doesn't tell you much about battery condition.

[holokai.man]

Hi, I have read all the posts and would like to emphasis to concentrate on a step that is in 'Maine Sail' post.
Step# 6::
"#6 You need to confirm there is continuity between each bank and the relative studs for each bank on the relay. A blown fuse on one bank makes the circuit incomplete."

I mention this as I did not see (or I missed it) that the fuse between the combiner and your house battery bank was mentioned. The manual calls for a 120 amp or smaller fuse to be installed.
Check continuity to ensure the fuse is good.
ALSO take a voltage reading between term. #30 on the combiner, and the positive on the house bank. There should Never be a voltage reading over
around .3 volts (3 tenths of a volt). If you read 1 to 14 Volts between these two points, the fuse is bad Or a definite 'Open' between term. #30 and the positive post of house bank.
I hope you find and are able to fix the issue you have.
Kind Regards,
Bob

[simonpickard]

Thanks for all the info. Lots more for me to check tomorrow.
I did inspect all the large fuses and they all seemed fine. I'll check again tomorrow.

I have a guy coming to test the system tomorrow. The good news is it's currently not working so I'm hoping with the tests you've mentioned, which I'll make sure he does from this.

I'll report back want it was in the end.

Regards,
Simon



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