Gel vs Acid

[ozrockrat]

Wet Acid battery (in some cases)

If you are going to be off the beaten track and you fully discharge a gel battery it will not recover without a special charger. At least with the acid battery any farmer / jump start will get you going and the bikes system will generally recover the battery.

Saying that I bought a BMW gel one last time just for the warranty and my potential for leaving the bike in storage for long periods. With the supposed lower static discharge rate I am hoping that it will last through the 2-3 month storage (no power for optomisers).

 

[Nin]

These were the exact requirements I set for my search & was why I went down this route...

More cranking power than an Odyssey, capable of cranking for longer & much cheaper...

Hi Paul

Can you recall where you got yours?

An Ebay search hasn't turned anything up for me ...

Ta

Nin

 

[Steptoe]

Wet Acid battery (in some cases)

If you are going to be off the beaten track and you fully discharge a gel battery it will not recover without a special charger. At least with the acid battery any farmer / jump start will get you going and the bikes system will generally recover the battery.

).

The gel is no different to a wet battery in that respect - your thinking of the gel-mat type of batterys , i.e. the odessy types.

 

[ozrockrat]

The gel is no different to a wet battery in that respect - your thinking of the gel-mat type of batterys , i.e. the odessy types.

Ah yeah now come to think of it that bastard of a thing was an oddessy. But why did the joker at the BM shop tell me I needed a "Special" BMW charger for my new gel battery??? Bugger saw the sheep shit on my boots and was taking the piss was he.

 

[Paul Young]

Hi Paul

Can you recall where you got yours?

An Ebay search hasn't turned anything up for me ...

Ta

Nin

Here's the ebay item:

http://cgi.ebay.de/12V-22Ah-Blei-Ge...ryZ49789QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

HTH

 

[Nin]

Here's the ebay item:

http://cgi.ebay.de/12V-22Ah-Blei-Ge...ryZ49789QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

HTH

Cheers Paul

now how did I miss that?

 

[snoopy]

Re: charging Gel batteries

Instead of buying a specialised charger get a cheap 12v power supply which has a REGULATED supply (look on the transformer for unregulated/regulated).

They are all over the place, my external hard-drive to my right is [email protected] regulated which would do the job.

 

[Greg Masters]

They are all over the place, my external hard-drive next to me right is [email protected] regulated which would do the job.

Erm, no.

You need more than 12v.

Greg

 

[snoopy]

I'm talking about kick starting a dead battery to get it on a standard charger so that the internal resistance is high enough not to fry the battery. But yeah it won't fully charge it (well it'll get it close to 11.6v in a long time).

 

[Greg Masters]

For that you may need up to 40 or 50v.

What's important with gel batteries is to control the current, less so the voltage.

Greg

 

[snoopy]

The only voltage you supply is the rating + enough to get over the internal resistance of the battery. The internal resistance of a GEL when dead is at least < .5 ohm.

R= V/I so that's 100W of heat generated by the battery if you put 50v across it!!

"Gel acid batteries are better at only approximately 16% internal resistance and require only roughly 116% of rated capacity to be fully charged. ..."

http://www.lifelinebatteries.com/rvcomps.php

 

[Greg Masters]

The internal resistance of a GEL when dead is at least < .5 ohm.

.... only if not suphated or suphating. The internal resistance then rises exponentially against time and lowness of charge. THEN you need a high voltage (Optimate uses 22v) to overcome the internal resistance to get any charge into the battery.

As I said before, for gel batteries controlling current flow is all important.

Greg

 

[snoopy]

You've got it the wrong way round! Batteries have less internal resistance when they are not charged (not sure where you are going with the sulphate..?).

Optimate is for acid batteries which have a higher internal resistance period - hence the lower crank power. 22v@W on a dead Gel would still fry it. 13.92v is the optimal starting voltage for a dead Gel (12x1.16, see that link).

 

[Nin]

Hi Paul

thanks again - just recieved and fitted it today.

A damn fine product for £36 delivered!

Nin

Here's the ebay item:

http://cgi.ebay.de/12V-22Ah-Blei-Ge...ryZ49789QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

HTH

 

[Paul Young]

Hi Paul

thanks again - just recieved and fitted it today.

A damn fine product for £36 delivered!

Nin

You're very welcome & that's what I thought....