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Most lead acid batteries are crap at accepting a charge-usually 25 % of their Ampere hour capacity. Consequently, the alternator output must be sufficient to charge the battery quickly. Even the most expensive lead acid batteries cannot overcome the problem of low charge acceptance. Absorbed Glass Mat (AGM) is of the lead-acid technologies. The low internal resistance of the AGM makes it super fast when it comes to accepting and delivering current. It can be charged very quickly and is super good at delivering current for starting the engine.

An interesting variation on the AGM is the spiral cell Optima.

Note for the technically minded:

Good quality gel or AGM batteries might have a Peukert number around the 1.1 mark while standard flooded types could be 1.3 and upwards. The cheapest batteries might hit a dismal 1.8

You've probably got it sorted by now.

Buy AGM. Check your alternator output to see that it is up to charging your batteries.

I'm fitting AGM's to my boat .

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I'm fitting AGM's to my boat .

 

what batteries do you fit to your private jet, pete ?

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Most lead acid batteries are crap at accepting a charge-usually 25 % of their Ampere hour capacity. Consequently, the alternator output must be sufficient to charge the battery quickly. Even the most expensive lead acid batteries cannot overcome the problem of low charge acceptance. Absorbed Glass Mat (AGM) is of the lead-acid technologies. The low internal resistance of the AGM makes it super fast when it comes to accepting and delivering current. It can be charged very quickly and is super good at delivering current for starting the engine.

An interesting variation on the AGM is the spiral cell Optima.

Note for the technically minded:

Good quality gel or AGM batteries might have a Peukert number around the 1.1 mark while standard flooded types could be 1.3 and upwards. The cheapest batteries might hit a dismal 1.8

You've probably got it sorted by now.

Buy AGM. Check your alternator output to see that it is up to charging your batteries.

I'm fitting AGM's to my boat .

 

Ummm, no. Most car alternators are not up to charging any battery beyond what is needed to top them off after a start. If you try and do bulk charging then the alternator will overheat. Most AGM equipped cars with stop start have much chunkier alternators and some are watercooled to cope with this issue.

 

AGM's need a lower float voltage than a flooded cell and if you swap them over they will probably have issues unless the car charge circuit is adjusted.

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You could do a lot worse than having a chat to South Yorkshire Battery Services.

 

South Yorkshire Batteries. Looks like a good maker to me. It's the purity of the lead that makes most of the difference. Plus how they support the lead plates : plastic net is a good idea :stops the gunge they put between the plates from falling out when the battery is thumped. Impurities in the lead can make another set of batteries which discharge the main battery. The amount of gap below the plates affects whether the stuff that falls off the plates will act as a short circuit across main plates or not. BT uses lead/acid batteries like I've described in telephone exchanges and they are guaranteed for many years (I think 20 years) because they are well made but not AGM types.

Edited by woolyhead

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Standby batteries for exhanges are fundementally different to SLI ones for cars and you cannot really compare the two. They do last a very long time though as you say.

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Good one Joker,

I don't have a Gin Palace. I have a Contessa 26 classic yacht- Bermuda rig. Small blue water cruiser. "More cocoa Number One "? (Jack Hawkins. The Cruel Sea ).

Refitting her to bring her up to scratch for the North Sea. AGM batteries are going in very soon-plus new upgraded alternator.

 

No plans on learning to fly and buying a plane.

 

keep on making us laugh Mr Joker.

 

---------- Post added 14-03-2018 at 15:33 ----------

 

Obelix,

 

Fundamentally don't disagree. My AGMs are going in along with an upgraded alternator for the Yamaha 1 GM 10 hp auxiliary engine in "Anita A" Contessa 26.

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my battery is running on empty nearly so i need a replacement where sells cheapish batteries i have been quoted £265!!!!!! and that is just the battery help with forumers.

 

 

Many thanks

 

I will give you a fiver for the old ones

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There’s batteries used on classified advertising sometimes cheaper than in shops

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20 minutes ago, Top Cats Hat said:

No it doesn’t.

 

This system is simply snake oil for gullible Americans.

I followed the link from MargaretF but Oh my god that video went on and on and on I swear Im now a little dimmer for watching it. After around 10 minutes Id heard how sad this blokes story was, how amazing this process is, how easy it is and how it changed his life and his families life with not a single mention of the actual process involved. I didnt end up watching the whole thing.

Total mind rot.

 

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3 minutes ago, Waj said:

not a single mention of the actual process involved. 

 

There is no process, just standard things you can do to extend the life of a battery like checking for sulphation, changing the acid and ‘pulse charging’ it, but all these methods will only work on relatively recently discharged batteries and even then will probably add no more than 10-20% to capacity and extend the life for six months or so.

 

Let’s face it, with the price of lead, if car batteries could be reconditioned the industry would be doing it themselves.

 

As I said, snake oil for the gullible!

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1 minute ago, Top Cats Hat said:

There is no process, just standard things you can do to extend the life of a battery like checking for sulphation, changing the acid and ‘pulse charging’ it, but all these methods will only work on relatively recently discharged batteries and even then will probably add no more than 10-20% to capacity and extend the life for six months or so.

 

Let’s face it, with the price of lead, if car batteries could be reconditioned the industry would be doing it themselves.

 

As I said, snake oil for the gullible!

Excellent point

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