Battery issues

[CliveG]

We have been having problems with the domestic power this year on Sirenia.
The domestic battery is made up of 4 No. 6v 225Amp/hr batteries

Without any load the the system showed about 12.5 volts.
As soon as any load was applied the voltage dropped.
The other weekend a bilge pump ran when we tacked and all the nav instruments shut down.
The voltage had dropped to 10.5v.
With the engine running the 70 amp alternator was shown to be delivering over 100 amps.

We had a bit of a look at things last weekend and could not really find a reason for this apart from some duff batteries.
The batteries are only 1 year old so this was very annoying.

Today I have been down to have another go at things and to measure up the battery bays for new batteries.
Each cell of all the batteries showed at least 2v and this was not dropping when a load was applied.
This started me thinking.
I tried splitting the bank in 2 and in doing so I re-made the connections to the batteries.
One bank then held to 12.5v with load applied.
I then set to and cleaned up all the battery terminals.
I then fired up the Eber and the voltage held up.
Problem cured. No need to get new batteries.
I am now a happy chap.

 

[sailorman]

We have been having problems with the domestic power this year on Sirenia.
The domestic battery is made up of 4 No. 6v 225Amp/hr batteries

Without any load the the system showed about 12.5 volts.
As soon as any load was applied the voltage dropped.
The other weekend a bilge pump ran when we tacked and all the nav instruments shut down.
The voltage had dropped to 10.5v.
With the engine running the 70 amp alternator was shown to be delivering over 100 amps.

We had a bit of a look at things last weekend and could not really find a reason for this apart from some duff batteries.
The batteries are only 1 year old so this was very annoying.

Today I have been down to have another go at things and to measure up the battery bays for new batteries.
Each cell of all the batteries showed at least 2v and this was not dropping when a load was applied.
This started me thinking.
I tried splitting the bank in 2 and in doing so I re-made the connections to the batteries.
One bank then held to 12.5v with load applied.
I then set to and cleaned up all the battery terminals.
I then fired up the Eber and the voltage held up.
Problem cured. No need to get new batteries.
I am now a happy chap.

Do you sub-contract to the National Grid ( 4 x 225 Ah )

 

[elton]

Quite common for poor connections to look OK, until the load increases. Not many people know that.

 

[CliveG]

Do you sub-contract to the National Grid ( 4 x 225 Ah )

The National grid can look after themselves.

The bank is only 450 amp hours as each battery is 6 volts.
The other bonus is that the weight of the bank on the port side balance up the new 13 gallon fuel tank on the starboard side.

 

[CPD]

Interesting to know Clive, as although I have recently replaced my batteries, I believe I may have similar issues. The next big job on my list is to fit VSR's which will entail dismantle and rebuild of the supply/charging cabling, so shall be extra careful on the rebuild.

 

[PaulGooch]

Interesting to know Clive, as although I have recently replaced my batteries, I believe I may have similar issues. The next big job on my list is to fit VSR's which will entail dismantle and rebuild of the supply/charging cabling, so shall be extra careful on the rebuild.

VSR's, good idea ? Relays ? Boats ? Salty air ?

Particularly on a mobo, i'd suggest twin battery banks with split charge diode's as a better option. If you have shore power, great, if not an advanced alternator regulator with the diodes offers a good charging solution, with great reliability.

 

[FullCircle]

VSR's, good idea ? Relays ? Boats ? Salty air ?

Particularly on a mobo, i'd suggest twin battery banks with split charge diode's as a better option. If you have shore power, great, if not an advanced alternator regulator with the diodes offers a good charging solution, with great reliability.

I have had VSRs for 4 seasons now, no issue so far. An ongoing experiment shall we say.

Pleased you have been able to save the money Clive.

 

[Sixpence]

Sticking with the KISS principle this year, but next winter will probably involve a rewire during which I'll be adding a few things of a technical nature, I'll be listening out for reports on how these things survive life aboard, so hope Jim and Clive report back later in the season. Good to hear you found the problem Clive, simple as it might seem to be, it's far from easy to find the answer sometimes

 

[CliveG]

VSR's, good idea ? Relays ? Boats ? Salty air ?

Particularly on a mobo, i'd suggest twin battery banks with split charge diode's as a better option. If you have shore power, great, if not an advanced alternator regulator with the diodes offers a good charging solution, with great reliability.

I have a VSR as part of the BEP battery switch cluster.
I find it much better than the old 1-2-both switch as I don't have to remember to switch anything over once the engine is running.
The VSR is embedded in some sort of epoxy to protect it from harm.
I always understood that split charge diodes can give a voltage drop and therefor limit the amount of charge the battery gets.

We will be trying to fit a Sterling alternator regulator this weekend.
Wish us luck