invertor

[Karl]

Hi when away from the marina my batteries last about four days using all the facilities including 240v applainces such as tv when out on the canal. if The invertor amber light comes on to say batteries low I start the engine to give the batteries a boost. Do I leave the invertor on when engine running to charge the batteries or run the engine with invertor switched off ? I don't know weather the batteries will charge with the invertor switched off ! Also how long do I run the engine for to give them a decent charge ? Many thanks.

[mrsmelly]

The inverter will not effect engine battery charging so do whatever you wish. What I would say is that waiting for the low battery warning light to come on is very bad form and will ruin your batteries very quickly. Its impossible to say how long to run engine for but you should fully charge batteries every day if possible or certainly every two days. Without knowing all the specifics I would guess you need an 8 hour charge from low warning light coming on anyway????

[MtB]

8 minutes ago, mrsmelly said:

Without knowing all the specifics I would guess you need an 8 hour charge from low warning light coming on anyway????

 

The low warning light on an inverter may not come on until well below the recommended max battery discharge of 50%. It may well not illuminate until batts are down to well under 12.00v, effectively 100% discharged.

 

Read the inverter manual to see if it states what voltage, and report back. Or just tell us the make and model of inverter. 

 

To fully recharge a properly flat battery would typically take about 12 hours of engine running, depending on myriad factors like capacity of battery, output of alternator, engine running speed etc etc...

 

 

 

 

Edited October 26, 2019 by Mike the Boilerman
Add a bit

[MtB]

23 minutes ago, Karl said:

I don't know weather the batteries will charge with the invertor switched off !

 

Yes they will.

 

The inverter is a load device, not a charging device. So whatever you have for charging will still charge when you turn it ON, regardless of whether the inverter is turned ON or OFF.  When turned ON however, the inverter will be constantly drawing a small current even when you are not using anything 240v, and this small current will be constantly reducing the charge in your batts, and being subtracted from the charger current when charging, so it is a good policy to keep the inverter OFF unless you are using it. 

 

 

[WotEver]

52 minutes ago, Karl said:

Hi when away from the marina my batteries last about four days...

Have you read this..?

 

[Karl]

48 minutes ago, Mike the Boilerman said:

 

The low warning light on an inverter may not come on until well below the recommended max battery discharge of 50%. It may well not illuminate until batts are down to well under 12.00v, effectively 100% discharged.

 

Read the inverter manual to see if it states what voltage, and report back. Or just tell us the make and model of inverter. 

 

To fully recharge a properly flat battery would typically take about 12 hours of engine running, depending on myriad factors like capacity of battery, output of alternator, engine running speed etc etc...

 

 

 

 

Hi, we have a Victon 3000 and 5 110amp leasure batteries which are a few months old. we have a standard alternator to charge starter battery and a bigger one to charge leisure batteries. We have been running on batteries for a bout 4 days without a decent engine charge and only just been told we should turn the invertor off of a night when in bed as using electric we don't need. Is this right ?

 

[MtB]

1 minute ago, Karl said:

Hi, we have a Victon 3000 and 5 110amp leasure batteries which are a few months old. we have a standard alternator to charge starter battery and a bigger one to charge leisure batteries. We have been running on batteries for a bout 4 days without a decent engine charge and only just been told we should turn the invertor off of a night when in bed as using electric we don't need. Is this right ?

 

 

Yes definitely. 

 

Do you have any battery monitoring devices? Like a SmartGauge or a Victron BMV? 

 

What do they say the battery voltage is when the inverter starts indicating low batts?

 

 

 

 

 

[Karl]

1 minute ago, Mike the Boilerman said:

 

Yes definitely. 

 

Do you have any battery monitoring devices? Like a SmartGauge or a Victron BMV? 

 

What do they say the battery voltage is when the inverter starts indicating low batts?

 

 

 

 

 

we don't know how accurate it is but it went down to about 12.44. when we start engine goes up to 14.66. we also have solar panels but in todays weather not much use I recon.

[MtB]

1 minute ago, Karl said:

we don't know how accurate it is but it went down to about 12.44. when we start engine goes up to 14.66. we also have solar panels but in todays weather not much use I recon.

 

Prolly very accurate given it displays to two decimal places. 12.44v is not a disaster. About 50% discharged IIRC. Definitely time for a day of engine running though.

 

And yes, God will have turned OFF all solar today!

 

 

[Karl]

1 minute ago, Mike the Boilerman said:

 

Prolly very accurate given it displays to two decimal places. 12.44v is not a disaster. About 50% discharged IIRC. Definitely time for a day of engine running though.

 

And yes, God will have turned OFF all solar today!

 

 

many thanks. we had problems a few months ago and found when off shore power we only had power out of battery for a few hours or so. We had a bettery test done and new alternator belts fitted. Since then all seams fine. I think this time because we have been out more than a couple of days we should have started the engine for longer and turned the Victron off over night. Many thanks for your help. 

we had new batterys fitted with the belt !!!!

[MtB]

1 minute ago, Karl said:

many thanks. we had problems a few months ago and found when off shore power we only had power out of battery for a few hours or so. We had a bettery test done and new alternator belts fitted. Since then all seams fine. I think this time because we have been out more than a couple of days we should have started the engine for longer and turned the Victron off over night. Many thanks for your help. 

we had new batterys fitted with the belt !!!!

 

Do read and understand WotEver's battery primer. This is IMPORTANT as you are currently at risk of killing your new battery set.

 

 

(Simply from lack of knowledge, that is.)

 

 

 

[Karl]

battery primer ?????? sorry don't understand !

[WotEver]

12 minutes ago, Karl said:

battery primer ?????? sorry don't understand !

See post #5 above. 

[Dr Bob]

4 hours ago, Karl said:

Hi when away from the marina my batteries last about four days using all the facilities including 240v applainces such as tv when out on the canal. if The invertor amber light comes on to say batteries low I start the engine to give the batteries a boost. Do I leave the invertor on when engine running to charge the batteries or run the engine with invertor switched off ? I don't know weather the batteries will charge with the invertor switched off ! Also how long do I run the engine for to give them a decent charge ? Many thanks.

 

3 hours ago, Karl said:

we don't know how accurate it is but it went down to about 12.44. when we start engine goes up to 14.66. we also have solar panels but in todays weather not much use I recon.

My victon inverter manual doesnt give the low voltage threshold value but says 'the battery is almost fully exhausted'.

My inverter has never shown the low voltage light and I went down to 50% charge a few time so guess the OP's bank  must have been below 50% and maybe significantly below.

To the op....do you have a 240V fridge? If so then that's at least 110Ahrs out of your batteries but I would then leave the inverter on overnight.

I would think after 4 days of not running the engine and being more than 50% discharged you MUST get it back to full. 8-10 hours of engine running maybe. Aim for a tail current of less than 10A at 14.6V.....and do it today if possible.

[blackrose]

 

Battery voltage can be related to state of charge, but if you're doing this remember that readings must be taken with no charge or discharge and ideally after several hours without charge or discharge which isn't very practical unless you've been away from the boat for some time and just returned. It's also temperature related to some degree but we can forget about that for the purposes of establishing approximate SoC.

 

Edit: There are different tables available depending on your battery type. This one is for AGMs for example:

 

Edited October 26, 2019 by blackrose

[cuthound]

7 minutes ago, blackrose said:

 

Battery voltage can be related to state of charge, but if you're doing this remember that readings must be taken with no charge or discharge and ideally after several hours without charge or discharge which isn't very practical unless you've been away from the boat for some time and just returned. It's also temperature related to some degree but we can forget about that for the purposes of establishing approximate SoC.

 

Edit: There are different tables available depending on your battery type. This one is for AGMs for example:

 

 

A small discharge won't make any appreciable difference to the voltages or corresponding state of charge.

[blackrose]

18 minutes ago, cuthound said:

 

A small discharge won't make any appreciable difference to the voltages or corresponding state of charge.

 

Really? Define small. I'm struggling to think of another factor that would make more of an appreciable difference to the voltages and corresponding SoC other than a big discharge.

[Alan de Enfield]

29 minutes ago, cuthound said:

A small discharge won't make any appreciable difference

According to the TV adverts you can get some something for that,

Caneston or something similar.

[cuthound]

15 minutes ago, blackrose said:

 

Really? Define small. I'm struggling to think of another factor that would make more of an appreciable difference to the voltages and corresponding SoC other than a big discharge.

 

Up to about 5% of battery capacity. As you day it is only relatively heavy loads that depress the battery voltage enough to affect the calculated SoC.

 

However immediately after taking a battery off charge its voltage is artificially raised by a phenomenon called surface charge. To get the true SoC on a recently charged battery, you can dissipate the surface charge by connecting a largish load for a few seconds, and then take the open circuit voltage to accurately assess the SoC (although obviously the SoC is going to be 100% or thereabouts).

 

Edited October 26, 2019 by cuthound
Phat phingers

[Sea Dog]

1 minute ago, cuthound said:

Up to about 5% of battery capacity. As you day it is only relatively heavy loads that depress the battery voltage enough to affect the calculated SoC.

 

However immediatelt after taking a battery off charge its voltage is artificially raised by a phenomenon called surface charge. To get the true SoC on a recently chsrged battery, you can dissipate the surface charge by connecting a largish load for a few seconds, and then take the open circuit voltage to accurately assess the SoC (although obviously the SoC is going to be 100% or thereabputs).

 

Did you type that on my phone? With my thumb?

 

[cuthound]

1 minute ago, Sea Dog said:

Did you type that on my phone? With my thumb?

 

 

Lol, no my phat phingers did it all on their own! ? 

[Sea Dog]

1 minute ago, cuthound said:

 

Lol, no my phat phingers did it all on their own! ? 

Then perhaps we should form a club!

 

[cuthound]

1 minute ago, Sea Dog said:

Then perhaps we should form a club!

 

 Look, I have enough trouble hitting the correct keys with my phat phingers. If I used a club my posts would be indecipherable. ?

[Sea Dog]

2 minutes ago, cuthound said:

 Look, I have enough trouble hitting the correct keys with my phat phingers. If I used a club my posts would be indecipherable. ?

A thumping repost, sir!

[mrsmelly]

7 hours ago, Karl said:

Hi, we have a Victon 3000 and 5 110amp leasure batteries which are a few months old. we have a standard alternator to charge starter battery and a bigger one to charge leisure batteries. We have been running on batteries for a bout 4 days without a decent engine charge and only just been told we should turn the invertor off of a night when in bed as using electric we don't need. Is this right ?

 

That will depend on your set up. My boat is all mains so the fridge and freezer are mains units so we never switch the inverter off.