New some help with buying Batteries guys.

[keith.]

You assume right engine is running at the time kieth.

 

 

In that case you need to run the engine until the amp reading is less than 4 amps. At that point if you could note how long the engine has been running (charging), the voltage and the SOC. You will then (hopefully) have fully charged batteries and will realise how long it takes and will be able to judge if your batteries perform any better whilst discharging.

 

Hire boats with no gauging usually recommend that their clients run the engine for 5 hours daily!!

[Greylady2]

In that case you need to run the engine until the amp reading is less than 4 amps. At that point if you could note how long the engine has been running (charging), the voltage and the SOC. You will then (hopefully) have fully charged batteries and will realise how long it takes and will be able to judge if your batteries perform any better whilst discharging.

 

Hire boats with no gauging usually recommend that their clients run the engine for 5 hours daily!!

Thank you very much kieth it's falling down now at 13.1 amps, the engine has been running for about 3 hours and the SOC is 100 so what I gather the SOC is not to be trusted at all.

[MtB]

 

 

In that case you need to run the engine until the amp reading is less than 4 amps.

 

 

Ok, here's an example of how something apparently simple gets complicated.

 

From advice to wait for a 1% tail current of 4A, I'm imagining the OP has about 400AH of battery installed.

 

Now given the batteries are believed to be knacked and probably only 200AH or less now, is a 1% tail current of 2A not now required to indicate fully charged?

[Paul C]

 

 

Ok, here's an example of how something apparently simple gets complicated.

 

From advice to wait for a 1% tail current of 4A, I'm imagining the OP has about 400AH of battery installed.

 

Now given the batteries are believed to be knacked and probably only 200AH or less now, is a 1% tail current of 2A not now required to indicate fully charged?

 

It probably gets more complicated than even that. We're not looking for a % of battery capacity as an indication of "fully charged", we are looking for an asymptotic approach to an unknown floor value of current, to indicate a pragmatic achieveable "fully charged" battery state.

 

A formula such as "1% of battery capacity" is only half the issue - the other half is the rate of change of that tail current tending towards zero.

 

I've put my finger in the air before and this figure is very much an interpretation (and for proper cost calculations, must also include the inefficiency in (for example) running an internal combustion engine to achieve this). BUT I'd say 1A/h is as good as any figure here.

 

Basically, after a little while reading up and understanding the curiousities of 12V boat electrics, one can use the gauges and other information to hand and make an educated guess as to when to discontinue charging. Its also worth noting, that having solar power makes this process/decision much simpler in spring/summer/autumn.

[cereal tiller]

 

It probably gets more complicated than even that. We're not looking for a % of battery capacity as an indication of "fully charged", we are looking for an asymptotic approach to an unknown floor value of current, to indicate a pragmatic achieveable "fully charged" battery state.

 

A formula such as "1% of battery capacity" is only half the issue - the other half is the rate of change of that tail current tending towards zero.

 

I've put my finger in the air before and this figure is very much an interpretation (and for proper cost calculations, must also include the inefficiency in (for example) running an internal combustion engine to achieve this). BUT I'd say 1A/h is as good as any figure here.

 

Basically, after a little while reading up and understanding the curiousities of 12V boat electrics, one can use the gauges and other information to hand and make an educated guess as to when to discontinue charging. Its also worth noting, that having solar power makes this process/decision much simpler in spring/summer/autumn.

So Greylady,now you can see why the Smart gauge was invented!

 

 

 

CT

[Eeyore]

Hope you get the charging regime sorted. I recently changed my batteries, and after looking around ended up buying from Halfords. They have a 30% discount on their 115Ah leisure at the moment, putting them at the top of the "reasonable" price band. No delivery charge/local pickup suited me at the time.

Regards

Steve (Eeyore)

Edited to add - they have the "magic eye" usually associated with sealed units, but also have six filler caps.

Edited June 28, 2016 by Eeyore

[Greylady2]

So Greylady,now you can see why the Smart gauge was invented!

 

 

 

CT

Yup :-)

Hope you get the charging regime sorted. I recently changed my batteries, and after looking around ended up buying from Halfords. They have a 30% discount on their 115Ah leisure at the moment, putting them at the top of the "reasonable" price band. No delivery charge/local pickup suited me at the time.

Regards

Steve (Eeyore)

Edited to add - they have the "magic eye" usually associated with sealed units, but also have six filler caps.

Thank you Steve

 

And thanks letting me know about halfords.

[Nightwatch]

I was to have a Smartguage installed when we have an electrical overhaul a year or two ago.

 

I was advised towards the Victron,I think the 702?. I am very happy with it. Yes,if your batteries are down it takes ages for the to charge at 4amps or whatever. A long cruise in a day normally does the trick. Have your engine running at the revs that give you the highest amp input reading.

 

I have had boats for over 14 years now and I'm just about getting my head round the electrics. Still not fully up to speed with it all.

 

Martyn

[Dave Payne]

My memory of your other thread is that your existing batteries still have enough life in them to keep you going for a while, albeit having to charge ore often than if you had a new set.

 

I effectively destroyed a set of 3 Varta Hobby 110Ah batteries in about 6 months, but kept them going for about another 18 months on about half their original capacity. In that time, I learned a lot about batteries and management without risking destroying another set.

 

I've had a set of 4 x Trojan T105 for just over a year now, and they seem to be doing fine i.e. not destroyed so the learning curve on a knackered set was worthwhile.

 

I added a Smart gauge monitor to my NASA BM2 monitor, and have the most comprehensive monitoring available without spending thousands.

 

This is the path i have chosen and i think makes good advice, just spent £150 on 3 x ebay 110Ah batteries as the ones that came with the boat were shot, was going to pull the trigger on more expensive ones but thought it might be best to spend time understanding what batteries can and cant do, push them to the limit so to speak and then when i understand better, invest in a decent set.

 

Or at least thats the plan.....

[ditchcrawler]

Right ive read the manual the victron battery monitor is showing 13.53volts 59.3 Amps at 87.3 SOC.

 

I know it's been said this is not accurate but it's all I've got until the man comes to look at the boat.

Thank you CT I wonder that now lol.

If that is with your engine running you still have a long way to go to reach fully charged. the 59.3 needs to read about 4 amps and forget the SOC it tells lies.

[Greylady2]

If that is with your engine running you still have a long way to go to reach fully charged. the 59.3 needs to read about 4 amps and forget the SOC it tells lies.

I got down to 7 amp after 5 or 6 hours but my dad wanted piece and quite.

 

Argghhh !

 

One thing I've noticed the SOC is dropping a he'll of a lot slower now. :-)

Edited June 28, 2016 by Greylady2

[Paul C]

I vaguely remember you randomly resetting the SOC on a previous post. Until you've fully charged the batteries, it won't read anything like correctly - and many will argue it won't read correctly even if you did fully charge them.

 

I also vaguely remember you mentioning you're getting solar power soon - once you do, the prolonged engine running won't be needed (until winter).

[BruceinSanity]

I got down to 7 amp after 5 or 6 hours but my dad wanted piece and quite.

Argghhh !

One thing I've noticed the SOC is dropping a he'll of a lot slower now. :-)

Hopefully it won't need anything like as much tomorrow.

[Greylady2]

Hopefully it won't need anything like as much tomorrow.

Yer hope so Bruce fingers crossed, I would of never known the SOC was a fibbing swine without the help of the forum. :-)

 

Thank you everyone for helping me.

I vaguely remember you randomly resetting the SOC on a previous post. Until you've fully charged the batteries, it won't read anything like correctly - and many will argue it won't read correctly even if you did fully charge them.

 

I also vaguely remember you mentioning you're getting solar power soon - once you do, the prolonged engine running won't be needed (until winter).

Paul that's true but it had been on the Jettie for about 20 hours.

 

To be honest it was going on float charge after about 3 hours?

 

God knows, maybe the charge hold off shore is poor.

 

All batterys are 4 years old. :-/

 

And the boat has not been used ont cut. 360 hours only.

 

Paul I can't wait you get solar panels.

 

Wags my tail. :-)

Edited June 28, 2016 by Greylady2

[Greylady2]

To add:

 

I think the alarm on low battery is set to 80% SOC but I can imagine the Amps would be more important.

 

Victron recommend 50% Alarm Rate ?

 

What does everyone else set their low battery too ?

 

I read the higher the setting the longer the batterys will last.

 

??

 

Geezas should of got a Motor home.

 

Only joking I lurve the boaty life :-)

Edited June 28, 2016 by Greylady2

[ditchcrawler]

To add:

 

I think the alarm on low battery is set to 80% SOC but I can imagine the Amps would be more important.

 

Victron recommend 50% Alarm Rate ?

 

What does everyone else set their low battery too ?

 

I read the higher the setting the longer the batterys will last.

 

??

 

Geezas should of got a Motor home.

 

Only joking I lurve the boaty life :-)

But you already know the SOC lies to you and the alarm will lie as well

[Greylady2]

But you already know the SOC lies to you and the alarm will lie as well

Very good point DC, I have it set on amps now and stuff the SOC.

 

Thing is though on setup it says I can adjust the SOC alarm.

 

No joke I was cooking a tikka massala in the 800w microwave and had a led 15 inch tv on. Boom everything went off the inverter shut down. SOC said 83.5.

 

I won't be looking at SOC again only Amps.

 

 

 

Edit : what happened to candles for light and pubs full of grog for entertainment and the odd fisty cuffs.

 

Non of this malarkey just a crank handle operated by a hung over navvy.

Edited June 28, 2016 by Greylady2

[ditchcrawler]

You 800w microwave was probably dragging 160 amps out of your batteries.

[Paul C]

You 800w microwave was probably dragging 160 amps out of your batteries.

 

Myth

 

My batteries store energy, not current.

[Greylady2]

You 800w microwave was probably dragging 160 amps out of your batteries.

Its only 5 minutes 2 times a week but yer the SOC was like watching the clock on Countdown on a Canundrum.

[ditchcrawler]

 

Myth

 

My batteries store energy, not current.

I was referring to the current flowing through the battery and probably drawing the voltage down not the total energy being removed from the battery. just to give OP an idea of how much instantaneous load that puts on the batteries. Its easy to say just 800 watts which for most people living on houses is negligible but for a boat dweller is quite high.

[Greylady2]

I was referring to the current flowing through the battery and probably drawing the voltage down not the total energy being removed from the battery. just to give OP an idea of how much instantaneous load that puts on the batteries. Its easy to say just 800 watts which for most people living on houses is negligible but for a boat dweller is quite high.

 

Appreciate your help DC.

[nicknorman]

Thank you very much kieth it's falling down now at 13.1 amps, the engine has been running for about 3 hours and the SOC is 100 so what I gather the SOC is not to be trusted at all.

Victron monitors tend to have the tail current set to 4% by default, ie 17A for you nominal 440AH. So once the current gets to that value, the SoC gauge will reset to 100% regardless of the actual SoC. Most people think this is far too high a current to stop charging and results in chronic undercharging.

 

My recommendation would be to change the tail current setting to 2% or ideally 1%. That will encourage you to keep charging until the batteries are actually pretty full. You said you were going to read the manual, and you will find out how to change the tail current setting there!

[Greylady2]

Victron monitors tend to have the tail current set to 4% by default, ie 17A for you nominal 440AH. So once the current gets to that value, the SoC gauge will reset to 100% regardless of the actual SoC. Most people think this is far too high a current to stop charging and results in chronic undercharging.

My recommendation would be to change the tail current setting to 2% or ideally 1%. That will encourage you to keep charging until the batteries are actually pretty full. You said you were going to read the manual, and you will find out how to change the tail current setting there!

Wow Nick thanks gor taking the time to write this, i read the manual but I need to find the screen abbreviation to change the tail setting.

 

I will post again when I've had a play with it Nick.

 

Cheers

 

Edit : I've change it to 1% Nick, Victron said minimum 0.5%. As you say it was set on Factory 4%

 

Thank you again

Edited June 29, 2016 by Greylady2

[Tony Brooks]

To GL2 and may other people out there.

 

The 800 watt microwave is almost certainly the "cooking power". If you look on the back you will see that actual power consumed is getting on for twice that. Hence Brians figure of about 160 amps.