Battery Advice Please.

[Brian422]

I have 5 Lucas Battery XV Supreme LK31MF 1000 MCA 110 Ah; 3 parallel supplying domestic power, 1 Engine Start and 1 Bow Thruster.

 

Accidentally left Victron Inverter on only to find shore power had failed and leisure batteries at 9v30.

 

Checked Inverter/ Charger settings and found they were still at Factory Default:

 

Gel/AGM, VictronEnergy, Gel Exide A200
D.C. Inverter input low shut down 9v30, input low restart 10v90.

Absorption voltage 14v40: Repeat Absorption time 1.00 Hr
Float voltage 13v80: Repeat absorption interval 7.00 Days.
Charge current 90A:Maximum absorption time 8 Hr

Shore current 16.0A

Transfer switch
Accept wide range of input frequencies.
AC low disconnect 180V: AC high connect 265V
AC low connect 187V: AC high disconnect 270V
UPS Function.

 

Although battery indicators are all green Ring RBA50 returned results all batteries bad;  reducing MCA to 500 and retesting indicated all batteries good; suspect reduced capacity.

 

I’d be grateful for any assistance in recommending battery types for each function (do I really require 5 Leisure Batteries) and configuring Victron Multiplus 12V/3000 VA/ 120 Amp Inverter Charger. 

 

Regards and Thanks

Brian.

[Tony Brooks]

1. Learn how to set the inverter to charge only as you leave the boat.  I think it discharged the batteries  by using the inverter to power the charger function.

 

2. Set the float charge to about 14.4V if you can and then charge the batteries all day. That might recover them. If the Victron will do an equalization charge do that as well. That may well recover the existing batteries. Set the float back to what it is now so you don't dry the batteries out.

 

3. You have five batteries and the inverter should not have discharged them all, probably only the three domestic bank so the other two may be fine.

 

4. Until you do a power audit, tell us what it comes out as  plus describing your charging regime I doubt we can tell you how many batteries you need.

 

5. I would recommend wet open cell batteries  from a reputable supplier and treat them as consumables. Only go expensive if you can monitor them and keep them all but fully charged.

[PeterF]

Its an inverter/ charger Multiplus type device, so it would have been running as a charger until shore failed when it became an inverter depleting the batteries, even the standby current could deplete the batteries over weeks. As Tony says, when you leave the boat, set the inverter to charge only.

[Brian422]

Hi both.

 

Thanks for the replies and advice.

 

I normally leave Multiplus on 'Charge Only' and, if you read second line of  OP, I did mention that I 'Accidentally' left Inverter 'ON'.

 

Normally Multiplus set to Charge Only with access to shorepower and when moving.

 

Have three alternators; 75Amp Starter, 150 Amps Leisure and 240 Volt Travel Pack, when things get desperate, using microwave or on move when using Washer/ Dryer

 

I'm confused as to Lucas Battery XV Supreme LK31MF 1000 MCA 110 Ah battery type. 

Exactly what category would best describe this battery type and are the default values, apart from D.C. Inverter input low shut down, acceptable?

 

Am I correct in assuming Power Audit is theoretical maximum demand on batteries as against practical where only a few items are in use?

 

Ring RBA50, according to manufacturer, measures batteries internal resistance which increases as battery ages.

 

Regards and Thanks

Brian.

 

 

Edited April 7, 2022 by Brian422
Additional information.

[PeterF]

The trouble with the inverter low voltage shutdown as you have found out is that a single value is not very good. It needs to allow for voltage drop in the batteries and voltage losses in the battery to inverter cables when under a heavy load, but this means that if the units is only supplying a small load, or self consumption then it can take the batteries down to a very low level. I have left my inverter (same model as yours) at the default settings. You could increase the low voltage cut off, but that may cause a premature shutdown when the inverter is supplying large loads.

 

In terms of the number of batteries, 3 is the minimum I would have for a 3000VA inverter and preferably 4.

 

The power audit is a calculation of what power you take from the batteries during a typical day on the boat so you can assess what capacity of battery bank you need. You might like to do a summer / winter / best case / worst case to look at the range.

[Tony Brooks]

I found a half decent description here https://12v-leisure-battery.org/

 

It seems it is just a lead calcium, flooded sealed battery. Lead calcium allows a higher charging voltage before gassing takes place but as it is sealed so you can't top it up it is probably wise to be conservative with the maximum voltage.

 

I would use the flooded lead acid battery setting with the absorption voltage set fro no more than about 14.5 volts (it may not gas until about 14.7). No automatic equalization but it would probably be OK to do a short equalization when the capacity has dropped but be aware this will start to dry the cells out.  Float at around 13.6 volts.

 

These figures are juts a guide and your charger will probably have something close as a preset.

 

Edited to add: It did not say if the battery uses pocketed plates (each plate in a glass fiber pocket) but for the price I hope it does. However it should not make any difference to the various voltage values.

 

Edited April 7, 2022 by Tony Brooks