Help Please!!, I am electrically challenged

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Daydream believer

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I have 2 new domestic AGM batteries. A 2 year old red flash starter battery. Coupled with a cyrix VCR 3 years old. Switching is individually to each bank plus another switch to join both banks in emergency. Switches all OK, no shorts etc.
Battery charger is a triple stage 15 amp Dolphin, new in 2003.
Battery monitor is a BM1 to domestic bank. I have set it up correctly using the ENG function when the new batteries were installed last week.
Batteries installed & charged on shore power for approx 7 hours to top up. I disconnected it from the shore then because its voltage went to float ( 13.2 V) & was inputting very little.
so everything was fully charged. Charger is set to charge starter first then domestics.

All batteries left with BM1 showing 13.1 V. EVERYTHING turned OFF
Next day voltage on BM1 records 12.8 V & .5 amp discharge. So I could not understand this.
I checked again nothing on.
I decided that the only things that could drain the batteries would be via the charge from the engine ( could it?) or to the battery charger which is permanently connected direct to the batteries.
So I disconnected the charger from the starter battery & the discharge dropped to .2 amps even though this is set to the domestics & i disconnected the starter.
I then realised I need not have disconnecetd from the battery. I could have just drawn the fuses. So I reconnected the starter battery & for some reason it still showed .2 amps. It did NOT go back to .5 amps as one might expect.
I then withdrew the fuses & I still show .2 amps discharge !!!. That could be an issue with the setting in the BM1 but I do not think so
I then put a volt meter across one of the removed fuses & it SLOWLY rose to 12 V ( Meter still set to Volts)

What i want to know is, Can a battery charger draw current from a battery that it is meant to charge? Does it sound as if some diode or electrical component in the charger has failed thus giving the odd readings? Would a new battery charger sort the issue or am I just wasting money
If it is a new one any recomendations for a charger to charge AGMs please
Sorry for the long post but any positive comment gratefully received
 
The proper charging regime for AGM is different to FLA and therefore your 2003 Dolphin is very unlikely to charge at the correct voltage (14.8v) and more likely is giving about 14.5v tops. I have the same issue with a much more recent CTEK M200.
So on that basis alone it is worth changing your charger, which also sounds like it is the problem (but that bit is beyond me for here).
If you are lucky, Paul Rainbow will be along but I think Paul recommends Victon chargers and that is what I would get in your boots - a two output one with the size depending on the size of the bank. A 15A charger is likely to charge everything up nicely unless it is a very large bank.
 
My Victron BMV-602 also shows a small discharge (around 0.17A) even when everything is switched off. However, when I leave the boat for a while, the batteries don't seem to lose much charge and it's not been a problem. I have assumed that it's an anomaly in the monitor formula.
 
Had odd goings on once, on newly acquired boat with volts on one (the engine)bank dropping even when battery master switches 'off' eventually traced to ignition/charge warning light wired direct to battery to 'energise' alternator., which explained why that glowed super faintly and only seen at night, Multimeter initially showed 0.5A drain and still did after disconnecting the excitation wire and further investigation revealed the gas sniffer was also permanently wired to this battery after which I rewired it via the master switch. All these oddities were the result of a poorly done electrics revamp job expensively done by so called professionals for the previous owners who had also screwed up installing an Adverc smart regulator a) by fitting wrong type and b)by connecting its sense lead to the rev counter terminal on the alternator instad of to field which required a solder job inside the alternator.
 
I think every charger which is connected to the batteries but not to the mains will slightly drain the batteries, but normally this 'back current' is very small.
For the CTEK chargers that I am familiar with in the region of 2.5 milliamps (figure given is less than 2 Ah/month).
 
Poecheng said:
The proper charging regime for AGM is different to FLA and therefore your 2003 Dolphin is very unlikely to charge at the correct voltage (14.8v)...
Click to expand...
Agree about the charger, but I find the proposed regime a bit too generalist. Like the OP I have a recent Red Flash starter battery and the recommended absorption voltage for this is 14.4 V if I'm not mistaken. On the other hand, the equally recent AGMs in the house bank can be charged at 14.7 V (although I do not think they are harmed by a slightly lower voltage, just get charged a bit slower).
So even if modern AGMs often can (or should) be charged at a higher voltage than used to be the case, this is not a strict rule. Check the specification of the battery.
 
Daydream believer said:
I have 2 new domestic AGM batteries. A 2 year old red flash starter battery. Coupled with a cyrix VCR 3 years old. Switching is individually to each bank plus another switch to join both banks in emergency. Switches all OK, no shorts etc.
Battery charger is a triple stage 15 amp Dolphin, new in 2003.
Battery monitor is a BM1 to domestic bank. I have set it up correctly using the ENG function when the new batteries were installed last week.
Batteries installed & charged on shore power for approx 7 hours to top up. I disconnected it from the shore then because its voltage went to float ( 13.2 V) & was inputting very little.
so everything was fully charged. Charger is set to charge starter first then domestics.

Sorry for the long post but any positive comment gratefully received
Click to expand...
Use your multimeter to check the current reading and determine if it is real or merely a figment of the battery monitor's imagination .
.
 
VicS said:
Use your multimeter to check the current reading and determine if it is real or merely a figment of the battery monitor's imagination .
.
Click to expand...
Did that this morning. The starter battery shows a .15 amp discharge. The domestics show a variety of readings from .3 to .5 amps. That fluctuating figure confuses me. The battery charger shows a voltage across one of the fuse terminals ( domestic supply)with the fuse removed of 11.95 V & across the starter supply of zero V
With the battery charger totally disconnected I am still showing .5 amp discharge on the battery monitor.
So I seem to have 2 issues one of a charger with a possible duff diode on the domestic side.( terminal 2) I am going to check this by taking that wiring & putting it from 2 onto terminal 3 ( It is a 3 battery charge charger)
Then somehow I have a short somewhere, so my only thought is that it might be one of the on/off mains switches. This might explain the varying discharge figures.I have 3 individual, domestic, starter & link both banks. NOT a rotary one. They all look clean- Is it a possibility?
There does not seem to be any leakage on the engine control panel lights & the switch is OFF there as well. It is also controlled by the mains switch to the starter battery, so one would expect it to be off. Turning on everything at the switch panel does nothing so there is no power leaking there unless the main supply is on.
 
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BabaYaga said:
Agree about the charger, but I find the proposed regime a bit too generalist. Like the OP I have a recent Red Flash starter battery and the recommended absorption voltage for this is 14.4 V if I'm not mistaken. On the other hand, the equally recent AGMs in the house bank can be charged at 14.7 V (although I do not think they are harmed by a slightly lower voltage, just get charged a bit slower).
So even if modern AGMs often can (or should) be charged at a higher voltage than used to be the case, this is not a strict rule. Check the specification of the battery.
Click to expand...
see #3
 
I recently installed a Victron SmartShunt and found it wasn't reading zero when everything was off.

In the app's settings I found a "Zero current calibration" and pressed it - it gave similar warning to that in the manual:

A zero current calibration is (almost) never needed. Only perform this procedure in case the battery monitor shows a current while you are absolutely sure that there is no actual current flowing. The only way to be sure of this is to physically disconnect all wires and cables connected to the SYSTEM MINUS side of the shunt. Do this by unscrewing the shunt bolt and remove all cables and wires form that side of the shunt. The alternative, which is switching off loads or chargers, is NOT accurate enough as it does not eliminate small standby currents.​

Sure enough, I disconnected everything from the negative side of the shunt and it showed zero.

I took Victorn's warning to mean that it's normal for there to be something in a boat system to be drawing a tiny current, and decided that it may be unrealistic to try and eliminate it completely. Maybe it's just (on my boat) the memory / security power connection to the FM radio.

I've just turned everything off again at the distribution panel by the chart table and checked - the Victron is showing a draw of 0.15A.
 
Interesting
I just disconnected 1 switch ( starter battery) & joined the 2 cables with a bolt. The discharge on the DOMESTICS fell from .5 to .2 amps. The draw was also lower with the switch on rather than off. So I will get 2 new switches. I still do not understand it because I reconnected only 1 domestic battery ( had to remove them to remove the switch) & now i get a 1 amp discharge ( double what i had when2 connected) & battery voltage of that battery has dropped alarmingly to 12.7 v. Something is drawing current. But I have disconnected all I can see-- except the cyrics VCR that connects domestic to starter & they are not supposed to draw any significant current. I am now wondering if there is some sort of flow from 1 bank to the other. But both show identical voltage.
Can the smaller Red Flash draw current from the larger domestics if the charger did not charge it properly. But i tend to discount that as there is still a current discharge with the starter battery -Ve disconnected
 
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BM1 / 2 manual:
Setting the zero-current
If no current is flowing into or out of the battery and a residual current is
shown on the display, the reading can be adjusted to zero.
With no current flowing into or out of the battery, press V&A until the
residual current is shown. Now press the key or the key to bring the
value to zero. (Note: eight presses of the key alter the setting by 0.1A). The
desired setting is stored when the V&A key is pressed to move to the other
setting again, or the ILLUM key is pressed to exit Engineering.”
 
I can read the instructions :rolleyes: . But do I set it to Zero if I know from my multimetre that there is a parasitic current of .5 amps.?
I did start off with the batt monitor at zero but it is now reading .5 amps discharge
Today I fitted 2 new switches & the BM1 shows the discharge down from .5 to.2 amps
The new switches have a noticeable stronger "click"
But in any event I am checking with a multimeter because it has been pointed out that battery monitors can be difficult.
I have ordered a Victron charger to ensure that the batteries are charged exactly the correct voltage as suggested in #7 above, even though my existing one charges within the general ranges acceptable to the manufacturers
 
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Daydream believer said:
I can read the instructions :rolleyes: . But do I set it to Zero if I know from my multimetre that there is a parasitic current of .5 amps.?
I did start off with the batt monitor at zero but it is now reading .5 amps discharge
Today I fitted 2 new switches & the BM1 shows the discharge down from .5 to.2 amps
The new switches have a noticeable stronger "click"
But in any event I am checking with a multimeter because it has been pointed out that battery monitors can be difficult.
I have ordered a Victron charger to ensure that the batteries are charged exactly the correct voltage as suggested in #7 above, even though my existing one charges within the general ranges acceptable to the manufacturers
Click to expand...

Hi DB, yes sorry that wasn’t helpful of me. I’m a keen amateur no professional advice here. If it was me and I had disconnect all from the service side of the BM1 shunt (negative service connection) and still The BM1 showed a current I would adjust it to zero. If not then it’s a real current I would set about trying to isolate where in the system it’s occurring by disconnecting each circuit systematically. It may well be fine, for example a piece of equipment needing a small current in stand by, just need to understand what is the culprit and rule out a short. I don’t like the idea of a “parasitic current” that I haven’t tracked down, could be about to get hot.
Regards, John.
 
Daydream believer said:
I can read the instructions :rolleyes: . But do I set it to Zero if I know from my multimetre that there is a parasitic current of .5 amps.?
I did start off with the batt monitor at zero but it is now reading .5 amps discharge
Today I fitted 2 new switches & the BM1 shows the discharge down from .5 to.2 amps
The new switches have a noticeable stronger "click"
But in any event I am checking with a multimeter because it has been pointed out that battery monitors can be difficult.
I have ordered a Victron charger to ensure that the batteries are charged exactly the correct voltage as suggested in #7 above, even though my existing one charges within the general ranges acceptable to the manufacturers
Click to expand...
When you say you have disconnected everything are you sure? Best advise in this situation is go back to basics.
I would remove the negative terminal from the batteries so there is absolutely no possibility of a stray current. If you have multiple house batteries just have the negative links connected between each house battery but nothing else. You need to be absolutely sure nothing else is connected, no battery monitor no charger etc. Just a bare battery terminal.
Disconnect every circuit you can from the house batterie bus bar or connectors. Then set your dvm to its current range, put both dvm terminals together and make sure it reads zero, (seen a few dodgy multimeters over the years), if it read zero then measure the current flow with your dvm between the battery negative post and the negative battery clamp that was previously disconnected. It should be below 0.002 amps as the bm1 only draws 1.5 mA. This is a starting point.
Not sure if you have done the above already, just trying to cover the way I would start this type of fault finding.
 
I am also ectronically challenged but it surprised me to learn that when the service batteries are switched off/key removed that not only does the bilge pump remain live as you might expect for surprise leaks etc but also in standard build spec the radio, tv and a few other things. You don’t say make/age of boat but I have read somewhere,perhaps on a Hanse owners forum ,of battery leakage due to connections. Maybe other owners of your make of boat might know Moore if revealed?
 
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