Batteries dont reach 100% charge

[j04n]

And that won't be charging anything - it's purely for 230V.

Unless I have the charge feature enabled on the Mastervolt 100/2000, but I guess that is pointless when the batteries are being charged directly by an alternator anyway. The current draw is confusing me as already stated it can be around 150 amps yet from memory the alternator ratings are 160, 80 and 50 so if the 160 is travel power only not sure where the high charge amps are coming from. I will have to check at the weekend when I am back. Need to get my head around this electrical circuit. I know it shouldnt be difficult its just tracing the cables!

Edited September 28, 2016 by j04n

[nicknorman]

No, probably the 160A is the domestic alternator. The travelpower alternator produces 300v or so and so the current is much less, around 16A, but anyway it's normally rated in terms of power (3.5kVA probably) rather than current. It's ability to charge batteries is limited by the Combi i.e. 100A.

Edited September 28, 2016 by nicknorman

[WotEver]

Simpler than tracing cables will be to check the voltages on the backs of the alternators. With the engine stopped the one that's the same voltage as the domestic bank is charging that bank etc.

[j04n]

No, probably the 160A is the domestic alternator. The travelpower alternator produces 300v or so and so the current is much less, around 16A, but anyway it's normally rated in terms of power (3.5kVA probably) rather than current. It's ability to charge batteries is limited by the Combi i.e. 100A.

Ok, thanks

[j04n]

Simpler than tracing cables will be to check the voltages on the backs of the alternators. With the engine stopped the one that's the same voltage as the domestic bank is charging that bank etc.

You are right. I did look when I got the boat a year ago but didnt make a note and am now going from memory ....... which isnt what it was ....... or what I remember it being!

[nicknorman]

Big alternator with conventional wiring - domestic

Smaller alternator - engine & BT

Big alternator with braided wiring - travelpower.

 

Simples!

 

What engine do you have?

Edited September 28, 2016 by nicknorman

[j04n]

Big alternator with conventional wiring - domestic

Smaller alternator - engine & BT

Big alternator with braided wiring - travelpower.

 

Simples!

 

What engine do you have?

Shire 65, Yanmar 4TNV98

[Robert Wood]

I have a NASA Marine BM-2 battery monitor which works very well (and you can actually see the display without having to get really close!). However I have noticed that when on shore power trickle charging, the capacity often sits around 87-90%. The reason for this is that in order to determine what the actual state of charge is, you need to discharge the battery by a small amount and see how the voltage holds up during the discharge. Only then can the monitor decide whether the battery was initially fully charged. Technically the indicated state of charge could go up from say 87% to 99% after a small discharge, although the actual state of charge has dropped from 100% to 99%! When cruising, it frequently shows 100% after a few hours' cruising, not because the charging is more effective, but because the battery bank is repeatedly being charged (engine running) and then discharged (engine stopped, lights on etc), so it can make a reasoned judgement. I would say if the battery is being trickle charged but isn't being discharged by anything, don't worry unless the indicated state of charge is less than 80% - it's the only way the monitors can work.

 

Hope this makes sense!

[j04n]

I have a NASA Marine BM-2 battery monitor which works very well (and you can actually see the display without having to get really close!). However I have noticed that when on shore power trickle charging, the capacity often sits around 87-90%. The reason for this is that in order to determine what the actual state of charge is, you need to discharge the battery by a small amount and see how the voltage holds up during the discharge. Only then can the monitor decide whether the battery was initially fully charged. Technically the indicated state of charge could go up from say 87% to 99% after a small discharge, although the actual state of charge has dropped from 100% to 99%! When cruising, it frequently shows 100% after a few hours' cruising, not because the charging is more effective, but because the battery bank is repeatedly being charged (engine running) and then discharged (engine stopped, lights on etc), so it can make a reasoned judgement. I would say if the battery is being trickle charged but isn't being discharged by anything, don't worry unless the indicated state of charge is less than 80% - it's the only way the monitors can work.

 

Hope this makes sense!

It does thanks. I will give it a go this weekend, Although I fear the problem is to do with the return amps never getting back to what theoretically has been taken out. The MICC requires 3 conditions to be met before it will return to 100% charge. 1) Charge amps <2% of domestic bank capacity. 2) Charge voltage >13.6V and 3) Ah consumed 0. It is 3 that is never achieved. As stated previously typically -50Ah per cycle. However, thanks again for posting. I will try along with other good suggestions made earlier. ........ so you have also had a MasterVolt MICC? lol the screen is very small. Maybe the final outcome will be to purchase a BM2 t install alongside.

[WotEver]

It does thanks. I will give it a go this weekend, Although I fear the problem is to do with the return amps never getting back to what theoretically has been taken out. The MICC requires 3 conditions to be met before it will return to 100% charge. 1) Charge amps <2% of domestic bank capacity. 2) Charge voltage >13.6V and 3) Ah consumed 0. It is 3 that is never achieved. As stated previously typically -50Ah per cycle. However, thanks again for posting. I will try along with other good suggestions made earlier. ........ so you have also had a MasterVolt MICC? lol the screen is very small. Maybe the final outcome will be to purchase a BM2 t install alongside.

 

Ignore everything except tail current when charging. When it's dropped to <2% and hasn't dropped for 45 minutes at Absorption voltage you can call it 100%.

[j04n]

 

Ignore everything except tail current when charging. When it's dropped to <2% and hasn't dropped for 45 minutes at Absorption voltage you can call it 100%.

I'm happy to WotEver. Its just the MICC isnt. I can manually reset just was hoping the equipment was intelligent enough for me not to have to. Also with manual reset, as the batteries are new, I am not sure if the cycles counter works. It doesnt appear to as I must have completed at least one full cycle by now but it is still showing zero. It would be a shame to loose that feature by manually resetting.

[Tony Brooks]

Note the absorption voltage bit. It will be at absorption voltage from an alternator but far too many battery chargers drop into float far too early unless "adaptive charging" is turned off.

I'm happy to WotEver. Its just the MICC isnt. I can manually reset just was hoping the equipment was intelligent enough for me not to have to. Also with manual reset, as the batteries are new, I am not sure if the cycles counter works. It doesnt appear to as I must have completed at least one full cycle by now but it is still showing zero. It would be a shame to loose that feature by manually resetting.

 

But it is well known that this type of meter is about as intelligent as a plank and by and large tell lies apart from amps and volts. This has been posted probably hundreds of times before but people still fall for the manufacturer's claims.

[j04n]

Note the absorption voltage bit. It will be at absorption voltage from an alternator but far too many battery chargers drop into float far too early unless "adaptive charging" is turned off.

 

But it is well known that this type of meter is about as intelligent as a plank and by and large tell lies apart from amps and volts. This has been posted probably hundreds of times before but people still fall for the manufacturer's claims.

I didnt! Although I probably would! It was on the boat when I bought it. The charger was dropping into float far too soon so I increased the trigger voltage from 13.6 to 14.0V

[rusty69]

There is a good write up on another lesser known site explaining the shortfalls of battery state of charge meters. I suspect it has also been discussed on here (the search function is your friend)/

[j04n]

There is a good write up on another lesser known site explaining the shortfalls of battery state of charge meters. I suspect it has also been discussed on here (the search function is your friend)/

Believe me Ive read most of them! Some of it sticks n some doesnt. The conclusion in most seems to be to buy a smartgauge but I'm trying to avoid it.

[Tony Brooks]

Believe me Ive read most of them! Some of it sticks n some doesnt. The conclusion in most seems to be to buy a smartgauge but I'm trying to avoid it.

 

Right - set it to volts before you turn in at night and make sure nothing electrical is running. Read the volts. That will give you a fair idea of the state of charge. Repeat when you get up as long as there is no solar input.

 

12.7 to 12.8 volts = more or less fully charged.

12.5 = about half discharged *

12.2 to 12.3 = fully discharged, time to charge *

 

 

* this is using the maximum of 50% discharged rule to optimise battery life. 12.5 actually = 75% charged & 12.25 = 50% charged.

 

The 50% "rule" helps to minimise the number of cycles the batteries have been subject to. if you keep the batteries well charged they will run out of cyclic life before sulphation destroys their capacity

[j04n]

 

Right - set it to volts before you turn in at night and make sure nothing electrical is running. Read the volts. That will give you a fair idea of the state of charge. Repeat when you get up as long as there is no solar input.

 

12.7 to 12.8 volts = more or less fully charged.

12.5 = about half discharged *

12.2 to 12.3 = fully discharged, time to charge *

 

 

* this is using the maximum of 50% discharged rule to optimise battery life. 12.5 actually = 75% charged & 12.25 = 50% charged.

 

The 50% "rule" helps to minimise the number of cycles the batteries have been subject to. if you keep the batteries well charged they will run out of cyclic life before sulphation destroys their capacity

Thanks for that Tony. I hope I havent already damaged the batteries as I know I have been down to 12 to 12.1 volts which I thought was 50%. I didnt realise I needed to keep the voltage as high as 12.3. Mind it was under load so maybe all is still ok. One of the problems is that my boat is quite power hungry. The alarm and central heating are all 240V AC so the inverter is ALWAYS on when off grid and moored. However, I will switch it off this weekend to try. Thanks

 

correction:- the alarm isnt AC but it is always on. The central heating is however AC

Edited November 9, 2016 by j04n