Cold Starting Question

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The "best" way to monitor a start system as well as the charging system is a digital volt meter wired to the starter feed.
 
The "best" way to monitor a start system as well as the charging system is a digital volt meter wired to the starter feed.
That means nothing unless you tell us where the meter leads are connected.

Connecting them to the battery terminals would monitor the voltage drop of the battery only. Connecting them at the starter and engine block would monitor the voltage drop of the battery and the cables.
 
"That means nothing unless you tell us where the meter leads are connected."

"digital volt meter wired to the starter feed. "

Wired to the starter the voltage DURING the starter operation is easy to monitor..

It usually will be about the same , 9-10Volts while cranking a larger engine.

In the same position it monitors the batt voltage , as if it were at the battery.

Most charging systems are far too weak for any charge voltage difference between the batt and starter.

For most its 150A Max at charge and size 4 starting cables.that will see 300 -700A during a start sequence.
 
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Resurrecting my old thread to update:

So I had a chance to take a look at the rig this past weekend. We had to go out and run the new autopilot thru its setup routine. I checked all battery and ground connections and they are all solid and secure, however, when I went to start up Dr. Perky he was still slow and weak. I switch to 'Combine' the batteries and he cranked very easily and strong. Yes, the starter battery is weak.

The current setup is an Iota 55 amp charger with a Balmar Duo Charge that is supposed to trickle-charge the start battery. It is apparently not accomplishing that task.

Looking at the Victron battery meter, the start battery is not getting a maintaining charge voltage (I think it read something like 12.35VDC sitting in the slip). My question is this: If the Duo Charge is supposed to trickle-charge the start battery when it detects a charging voltage on the house bank, does that mean that once the house banks are full and the voltage to them drops to just a trickle, won't the Duo Charge stop charging the start battery? Does that mean that the ONLY time I am actually charging the start battery is underway when the alternator is doing the charging and keeps a 14VDC on the system? Finally, wouldn't a charging relay have the same issue?

I have now decided to just leave the switch in 'Combine' so that the Iota can charge and maintain both banks at the dock and will separate when we are on the hook as not to kill the starter with house loads.

Sorry I can't be more specific about the details and numbers, but I hope you get the jist of my questions.

Tom-
 
Resurrecting my old thread to update:

So I had a chance to take a look at the rig this past weekend. We had to go out and run the new autopilot thru its setup routine. I checked all battery and ground connections and they are all solid and secure, however, when I went to start up Dr. Perky he was still slow and weak. I switch to 'Combine' the batteries and he cranked very easily and strong. Yes, the starter battery is weak.

The current setup is an Iota 55 amp charger with a Balmar Duo Charge that is supposed to trickle-charge the start battery. It is apparently not accomplishing that task.

Looking at the Victron battery meter, the start battery is not getting a maintaining charge voltage (I think it read something like 12.35VDC sitting in the slip). My question is this: If the Duo Charge is supposed to trickle-charge the start battery when it detects a charging voltage on the house bank, does that mean that once the house banks are full and the voltage to them drops to just a trickle, won't the Duo Charge stop charging the start battery? Does that mean that the ONLY time I am actually charging the start battery is underway when the alternator is doing the charging and keeps a 14VDC on the system? Finally, wouldn't a charging relay have the same issue?

I have now decided to just leave the switch in 'Combine' so that the Iota can charge and maintain both banks at the dock and will separate when we are on the hook as not to kill the starter with house loads.

Sorry I can't be more specific about the details and numbers, but I hope you get the jist of my questions.

Tom-

First, I would have your battery checked. You can buy a checker or take the battery to any battery retailer.

Second, the instructions for your charger should describe how it works and what it does. If you have any questions, the manufacturer can provide the most accurate information.

I wouldn't leave the battery switch in the "both" position because if your starting battery is weak or defective, it can damage the other batteries.
 
I have a load checker and it checks out. It's less than a year old (I know that doesn't mean much, but still).
 
I have a load checker and it checks out. It's less than a year old (I know that doesn't mean much, but still).

My son owns an automotive repair shop and has one of those load testers.
Several years ago I had him test my truck battery (Cummins diesel) because I thought it was turning over slow. The tester showed the battery to be good.
However I still bought a new battery....and boy did she turn over so much faster.
I don't trust those load testers on a diesel. That's my experience.
 
My son owns an automotive repair shop and has one of those load testers.
Several years ago I had him test my truck battery (Cummins diesel) because I thought it was turning over slow. The tester showed the battery to be good.
However I still bought a new battery....and boy did she turn over so much faster.
I don't trust those load testers on a diesel. That's my experience.

I too have had bad luck with the expensive electronic "do everything" models...too often as you describe the results and the battery were in "disagreement"....:D

The resistive types to me seem to be more reliable...but you should charge the battery up after a thorough and recheck with one of those babies...:eek:
 
Tom-- What I know about electricicals wouldn't cover the head of a pin. But if your charger is a three-stage or "smart" charger I believe-- but I could be wrong-- that it is intended to be "smart" for only one battery or battery bank, the one it's connected to. So it's possible-- again, not my area of expertise-- that by leaving your battery selector on All or Both you may be defeating the "smart" aspect of the charger because the two batteries or banks are not identical in characteristics.

We have two battery banks of 6vdc golf cart batteries. Prior to this we had two batteries, each an 8D. The battery selector is Off, 1, All, 2. Our Heart Freedom 25 inverter/smart charger is connected to the port battery, now bank, which is 2 on the selector. This is the bank we use as our house power supply.

So the only battery bank that gets the benefit of the three-stage smart charger is the port bank of 4 6vdc golf cart batteries ( formerly one 8D).

The Freedom 25 has two echo chargers, which are trickle or float charge only. One echo charge connection feeds the starboard bank of two 6vdc golf cart batteries (formerly one 8D) and the other echo charge connection goes to the generator's 4D start battery.

For reasons too complicated to go into here, when we ran the boat back when it had the two 8Ds, which meant charging current was being supplied by the two alternators only, we put the battery selector on All. Once the engines were shut down we moved the selector to 2.

But when the boat was on shorepower or the generator and the batteries were being charged by the inverter/charger we were instructed by our electrical shop to put the battery selector on 1 or 2 but not All as this could "confuse" the smart charger. The echo chargers kept the charge up on 1 and the generator battery.

(With our current golf cart battery setup we no longer need the combined power of both alternators so we no longer run the boat in All.)

The only time we were told we should use All on the selector when the batteries are being charged by the Freedom 25 is when we equalize the two main batteries (now banks). The echo chargers are to be disconnected, the selector put to All, and the Freedom put into its high-charge equalize mode. This will equalize both the main batteries (banks).

All of which is a long way of suggesting that perhaps leaving your selector in All or Both when the boat is in its slip on shorepower may not be a good idea unless your charger is equipped with an echo charger you can use for the start battery.
 
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My son owns an automotive repair shop and has one of those load testers.
Several years ago I had him test my truck battery (Cummins diesel) because I thought it was turning over slow. The tester showed the battery to be good.
However I still bought a new battery....and boy did she turn over so much faster.
I don't trust those load testers on a diesel. That's my experience.

You're not testing a diesel, you're testing a battery.

You need to be sure you're testing at a high enough load. A diesel engine typically draws more current (the starter does) when starting because of bigger and heavier parts.
 
never could find how big your house bank was...
did you read this in the Balmar Duo charge instructions?

Solenoid Drive
In applications where the Duo Charge is used to support larger capacity starting batteries (such as 4D and 8D models) or
windlass and/or thruster batteries, there may be instances when the 30-amp capacity of the Duo Charge’s circuitry may not
provide sufficient current to satisfy demands. When used as a stand alone charge source, the Duo Charge is designed to
discontinue charging when demands exceed its capabilities. At that point, the Duo Charge will wait for a short period and
query if the demand has diminished to below its 30-amp capacity. If so, the Duo Charge will continue charging. If demand
continues to exceed capacity, the Duo Charge will continue to shut down, while checking periodically to see if demand has
diminished.
If your application requires frequent charging levels in excess of 30 amps, it may be necessary to add a solenoid as a method


to manually bypass the Duo Charge’s internal circuitry. Keep in mind, the Duo Charge
will not automatically activate the solenoid

if the demand exceeds its capacity. As such, it is important to monitor charging voltage closely at the battery being
charged by the Duo Charge. To utilize the Duo Charge’s solenoid drive function, it will be necessary for the user to supply an
appropriate-capacity solenoid and a toggle or other ON/OFF

switching mechanism to control the bypass function.

I bought a switching solenoid that I couldn't use do to the mismatch in battery bank sizes.​

I'd try and look up more but it's getting tricky while tring to make Snow's Cut in the Cape Fear River with a screaming new moon ebb...:D

 
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If the Duocharge is set up correctly, then the next two suspects are the house bank, followed by the charger. The DC will not send a charge current to the start bank unless the house bank is fully charged. So if it doesn't sense the house bank as being charged, it will never send a charge to the start bank.It does not "trickle charge" the start bank. This could be caused by the DC not being properly adjusted, or by a bad house bank or the charger. See the instructions here for ways to properly test the condition of the battery banks:

Trojan Battery Company
 
Sorry all. I am sincerely trying to follow all this electrical stuff but what I "know" about electricity for certain is, it's invisable and can kill me. Is there perhaps a well regarded book that explains marine AC/DC electrical sytems?

I imagine the title I should start with would read something like "Boat Electrical For The Complete Moron".

I really wan't to develop a solid basic working knowledge of this stuff.
 
My Perkins 6 starts good down to freezing. It is on a mooring so no chargers or solar panels. Original starter too (rebuilt twice).
My experience is that multi-vis oil and 2-0 gauge cables are a must. A HD, diesel rated, 1,2,both switch and the bat. ground wire direcly to a starter mtg. bolt, brass or bronze bolts & lock washers (no SS) on cables. I always start in "both" switch position.
When it is below freezing, I have a small propane powered paint stripper that I place under the oil pan while having my first cup of coffee. Never fails.
 
If the Duocharge is set up correctly, then the next two suspects are the house bank, followed by the charger. The DC will not send a charge current to the start bank unless the house bank is fully charged. So if it doesn't sense the house bank as being charged, it will never send a charge to the start bank.It does not "trickle charge" the start bank. This could be caused by the DC not being properly adjusted, or by a bad house bank or the charger. See the instructions here for ways to properly test the condition of the battery banks:

Trojan Battery Company

I'm not sure this is the case. What is happening is when the house bank is fully charged the Iota goes into float mode, I THINK (I do not know) the voltage goes below 13VDC and that puts the DuoCharge into standby mode, therefore, NOT trickle charging the starter battery after the house bank tops off in the slip.

Does that make sense? That is what I think is happening.

**As a side note... My battery selector is currently set to 'Combine' and I am three hours away until Friday. You think it will tear something up in that time? I mean, the charger is just seeing 12VDC from a bunch of wet cells (four 6VDC and one 12VDC). Unlike my electrical idiot colleague, Craig :flowers:, I do understand electronics, so I don't see how it will confuse the charger at all. I will break out Nigel's book and see if he covers it.**

Thanks for the help so far, y'all!!!
Tom-
 
Definitely read Calder, he explains it all much better than I can. But you have two different animals trying to feed off the same mother's milk.. not always a good thing for one of them. IF things are as you describe, the IOTA is not doing it's job. There should be no trickle charging of the battery whatsoever. Again, and I mean this in a nice way, RTFM!
 
Ten months.

But you have two different animals trying to feed off the same mother's milk.

How is having my combiner engaged to a single charger, any different than a combiner relay?
 
How is having my combiner engaged to a single charger, any different than a combiner relay?


The question I would have is can the condition of one of the batteries connected via a combiner to a charger override the condition of the other batteries connected to the combiner in such a way that could adversely affect the other batteries?

In other words, would the charger respond to the condition of Battery A which might have some issue that causes it to demand a continuous high rate of charge which would then cause the charger via the combiner to apply that same continuous high rate of charge to Batteries B and C which didn't need a high rate of charge, thus cooking the hell out of Batteries B and C?

I don't pretend to have even an inkling of the answer. It's just the question that occurs to me when I hear about one multi-stage charger charging multiple batteries or battery banks that could be in different states of charge or condition.
 
Without reading the Duo Charge manual..because I don't have one and I'm not in a free internet zone right now to download one...

If the IOTA charger is just connected to the house bank...is it possible it will NEVER charge the start battey? Maybe the Duo Charge ONLY combines when the alternator is working through some "sense" and it's NOT just a voltage/amp read.

It does seem finicky as my last post from the manual stated.... that it had limitations depending on amp draw so I woud be looking there if I knew my battery banks were OK.
 
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Ten months.



How is having my combiner engaged to a single charger, any different than a combiner relay?

Because the way you described it, you have them combined full time now, giving you essentially two different battery types on the same bank, and each started out with a different level of discharge.
 
*FOLLOW-UP*

I found the issue. The 30A fuse between the Digital Duo Charger and the starter battery was popped. Probably pilot error on my part. Once I read the FULL instructions (thanks to posted that as I only have a abbreviated version), I was able to read the light flashing sequences and track down the problem. It seems to be performing correctly now and I am reading 13.6 VDC to the start battery now. Even while in float mode of the main charger.
 
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