Battery question

[dougg]

Hi.

Im Going to replace our 4 house batteries soon before leaving for the med.
I am torn between the Rolls 110a from Barden at 140 quid or 110a from the local chandelery ones at 79 quid. Both are wet sealed.

My Question is are the Rolls worth the extra money. or shall i have the cheap ones and replace them away in 4 years.

 

[earlybird]

Hi.

My Question is are the Rolls worth the extra money. or shall i have the cheap ones and replace them away in 4 years.

A few days ago I replaced my service battery since it was obviously not holding charge very well. It's a bog-standard truck battery of ~100aH capacity. The date of manufacture on the old one was mid 2003.
I suspect Rolls batteries would not give pro-rata improvement for the price.

 

[macd]

A few days ago I replaced my service battery since it was obviously not holding charge very well. It's a bog-standard truck battery of ~100aH capacity. The date of manufacture on the old one was mid 2003.
I suspect Rolls batteries would not give pro-rata improvement for the price.

I daresay that's often the case, but by the sound of it the OP's going to be living aboard and cycling the batteries much more frequently than most boats experience. In that case I'd lean towards spending more on batteries (but only assuming some sort of 'smart' regulator is fitted).

Can the OP tell us which Rolls battery he has in mind? Barden seem to offer both AGM and flooded "deep cycle".

 

[PeterGibbs]

Hi.

Im Going to replace our 4 house batteries soon before leaving for the med.
I am torn between the Rolls 110a from Barden at 140 quid or 110a from the local chandelery ones at 79 quid. Both are wet sealed.

My Question is are the Rolls worth the extra money. or shall i have the cheap ones and replace them away in 4 years.

Where I would focus attention is on the recharging regime: getting the best out of whatever you buy is probabaly more decisive than the brand name on the box. A 240v charger with phasing / engine alternator charger with same will give your new batteries the best chance of delivering their full capacity.

It also means that, in your case when staying aboard, if you know the frig is pulling most of a hot day, and you've not run the engine/been alongside, you may want to ease up on the load. Going beyond 50% discharge on your service batteries even a couple of times will impair their life.

PWG

 

[dougg]

Thanks,
I was going for the flooded ones.
Christec charger for the mains.
130 watt solar panel
MPPT controller
Air breeze wind gen

 

[pvb]

I am torn between the Rolls 110a from Barden at 140 quid or 110a from the local chandelery ones at 79 quid. Both are wet sealed.

I think I'd go for the better quality of Rolls batteries which, with care, should last many years.

However, I'm a bit confused because I can't see any "wet sealed" Rolls batteries on Barden's website. They list a wet 105Ah Rolls at £166, but not a 110Ah at £140?

 

[macd]

Thanks,
I was going for the flooded ones.
Christec charger for the mains.
130 watt solar panel
MPPT controller
Air breeze wind gen

Makes sense.
As I suggested before, would strongly recommend a 'smart' alternator regulator, but perhaps you already have one.
Not familiar with the Christec charger; does it include a equalising mode? Barden may recommend periodic equalization cycles.

 

[Conachair]

Last time i changed i went for t105 trojans. They are/were pretty much the "standard" for cruisers, which doesn't mean they are the best but if they were rubbish then everyone would not hold back in say so. Rolls have the reputation of being the top of the pile though maybe not best value for money. Again, who knows the reailty.

What I think is really important cruising is knowing how much charge is in there and getting the battery back up to full charge as often as possible. I suspect very few cruising batteries ever get past 80/90% charged.

Battery amp/hour meters drift , the best way most agree to measure state of charge is a hydrometer. Once in a while to check if the amphour meter is close or way off. The SG changes a lot with temp as well.

Getting fully charged with 130w solar may be unlikely if you have a fridge, and sorry but the wind gen might not do a lot in the med. Which means at anchor running the engine or living with batts whaich never get properly charged. I have a honda genny which gets used quite a lot running the mains charger and charing the laptop at the same time. Great for running power tools at anchor as well. Smart regulator on the alternator I found worked well at keeping the charge pumping into the batts as they got closer to fully charged, standard auto regulator tails off very quickly.
How many questions were there again?

And LED lights throughout!!!

 

[sailinglegend420]

...........Battery amp/hour meters drift , the best way most agree to measure state of charge is a hydrometer.......

A hydrometer will only measure the state of charge NOT that the battery has been charged back to its full capacity. A battery may be fully charged but it's capacity may have been reduced to well below its nominal value due to sulphation.

A battery monitor can help to show the Ah in and out to give you an idea of what's happening, but you're right they are not always accurate.

The best way is to see what the Battery Monitor charging current is when under charge from a proper multi-stage charger, with no other loads on the circuit. If its about 1% of the battery Ah rating then the battery is fully charged to the maximum capacity that it can absorb.

 

[dougg]

Thanks for the replies.

The Cristec charger is the CPS2 12v/40amp. im sure its also avail from Barden however ours was fitted from new.

80 amp Alternator fitted as standard.

Our volt meter / ameter fitted at the chart table shows a battery voltage of 13.8-14 volts when pluged in to the mains.

If i disconnect from the mains and induce a load of 9amps the battery voltage drops to 11.7 within 5 mins.

 

[dougg]

What does "equalizing" mean in relation to battery charging?

What is an alternator smart regulator and how will i know if i have one?

Ive checked to origonal batts and they are the open ones ie they have caps to check yhe electrolyte, this suprises me a little as they are in a rear cabin under a bunk.

 

[macd]

Open lead acid batteries can generally take a higher rate of charge than sealed ones, but with a modest 80Amp alternator and over 400Ah of batteries, that probably won't be an issue either way. My preference would be for open, especially if you're going somewhere hot, but follow Willow's observations and you won't go far wrong. He's the expert, not me.

Equalisation is sometimes called de-sulphation. Over time, sulphates build up on the battery plates, reducing their effective area. (This is often what eventually kills them.) Equalising is a method of charging a battery at a higher voltage, producing gassing, but with a limited current, which helps dissolve the sulphates. Gel batteries don't need equalising. Top-of-the-line manufacturers like Trojan, whose traction batteries are expected to receive very heavy use and deep cycling, recommend period equalisaton cycles. Some battery chargers have an equalisation cycle built-in. Yours seems not to have, but has a decent 3-stage spec. Sterling do a stand-alone de-sulphation gizmo for about £60. Easy to install, then pretty much fit and forget. That said, most liveaboards, I suspect, do without.

(Note that the Christec, I think, has user settings for the type of batteries it's connected to. Worth checking that they're set right. Output voltage is also adjustable.)

A normal alternator regulator is a crude thing piggy-backed onto the alternator itself. It won't charge the batteries much beyond 80%. 'Smart' regulators emulate the charge regime of your Christec, allowing a full charge and incidentally being kinder to the batteries long-term. If you've a gizmo about 100mm square or so and maybe 60mm deep and don't know what it is, wired to the alternator (but maybe some distance away), it may be one.

Your voltmeter may give an idea if there's a smart charger fitted. When running under engine, expect to see something around 14.7 volts if the batteries are somewhat depeleted, dropping to 13-odd when fully charged. A standard regulator would be unlikely to deliver more than 14.1. You should see the same sort of figures with the Christec.

If an expert comes along and says all this is cobblers, I'm happy to demur. So far it's worked for me.

 

[dougg]

Thanks for that. Im keen to get this right before we leave. just to clarify, do these deep cycle batts prefer to be topped up all the time or do they like to used to there full potential now and then. Our boat has been plugged into shore power for 99% of its 4 year life. Would this have damaged them.
Do i understand correctly that the engine alternator will only charge them to 80%?

 

[Plevier]

Thanks for that. Im keen to get this right before we leave. just to clarify, do these deep cycle batts prefer to be topped up all the time or do they like to used to there full potential now and then. Our boat has been plugged into shore power for 99% of its 4 year life. Would this have damaged them.
Do i understand correctly that the engine alternator will only charge them to 80%?

New lead acid batteries straight from manufacture often take a few cycles to develop full capacity. I can't explain that with fancy theory but it's what happens. After that the less they are discharged the better. They do not show memory effect i.e. they don't get "lazy". Keep them charged!

A normal engine alternator will be set at around 13.8 to 14.2V. At that voltage getting a battery really fully charged takes 2-3 days. Consequently the reality is that most starting batteries that are recharged just from engine alternators in cars or yachts tend never to get above 80-85% charge. However your blunt statement is a bit over simplified, it's not absolute.

It's different if you fit a smart regulator and use the engine a lot i.e. more likely a mobo than a yacht.

 

[Plevier]

Open lead acid batteries can generally take a higher rate of charge than sealed ones, but with a modest 80Amp alternator and over 400Ah of batteries, that probably won't be an issue either way.

Equalisation is sometimes called de-sulphation. Over time, sulphates build up on the battery plates, reducing their effective area. (This is often what eventually kills them.) Equalising is a method of charging a battery at a higher voltage, producing gassing, but with a limited current, which helps dissolve the sulphates. Gel batteries don't need equalising. Top-of-the-line manufacturers like Trojan, whose traction batteries are expected to receive very heavy use and deep cycling, recommend period equalisaton cycles. Some battery chargers have an equalisation cycle built-in. Yours seems not to have, but has a decent 3-stage spec. Sterling do a stand-alone de-sulphation gizmo for about £60. Easy to install, then pretty much fit and forget. That said, most liveaboards, I suspect, do without.

Modern batteries of the type you would use for domestics on a boat will all take a higher charge current than you are likely to provide, whether wet or sealed AGM. 0.5 A per Ah would not normally be a problem or even 1A/Ah for many. The wet one will take a higher voltage to achieve the current.

Gel batteries are completely different from AGM and only suitable for low rates of charge or discharge and I would say avoid. There are not so many around now.

Next paragraphs are for wet only - you can't equalise AGMs more than very rarely without ruining them.

I don't think equalisation and desulphation are the same. Equalisation is to bring all the cells back up to full charge. If on a low float voltage for some time (traditionally 2.15Vpc) they get out of step, equalising for a few hours at say 2.4 Vpc resolves this and also stirs up the electrolyte and gets rid of any stratification. Common practise used to be 3 monthly. It's pretty superfluous on modern systems floating at 2.25Vpc. (Float voltages have gone up as battery alloys have improved and gassing reduced.)

If you are deep cycling batteries frequently then you should be using a smart multi rate charger and an equalising charge should only be needed rarely. However if you are recharging deep cycled batteries at 2.35Vpc or less - alternator or typical simple charger voltage - which will be slow - equalising charges would be good but how are you going to provide them?

Desulphation processes usually rely on rapid shallow pulsing. When I was in the industry they were regarded as snake oil but a lot of people claim good results. I'm sure they have become more sophisticated as have smart chargers, with the wide adoption of switched mode designs. Batteries on a good use and charge regime shouldn't get sulphated in theory. It's prolonged standing less than fully charged that does the damage.