GEL Battery questions..

[modernjack3]

So I just bought a GEL Battery and a Battery protector where I can set the Voltage when it should cut off all the Devices currently hanging on the battery so it doesnt get damaged - But I have no idea at what voltage I should set it and I cant seem to find any info on the Internet either So if you guys could tell me at what Voltage I should cut the Devices from the battery so it doesnt get into the dangerous Zone please help me out.

Also I bought a MXS 5.0 Battery charger from Amazon to Charge it but it has multiple Modes - One AGM and a normal wet cell charging one , it says it Supports GEL charging but there is no mode for tht - so should I go with the wet cell or AGM charging mode ? ?

Thanks for your help guys !

[GEuser]

http://www.chargingchargers.com/tutorials/charging.html


2nd sentence .

[modernjack3]

http://www.chargingchargers.com/tutorials/charging.html


2nd sentence .

These are the "smart chargers", and quality units generally are not found in discount stores.

This is no help at all man...

[GEuser]

http://www.chargingchargers.com/tutorials/charging.html


2nd sentence .

These are the "smart chargers", and quality units generally are not found in discount stores.

This is no help at all man...

In the 2nd sentence it says>
"The peak charging voltage for Gel batteries is 14.1 or 14.4 volts, which is lower than a wet or AGM type battery needs for a full charge. Exceeding this voltage in a Gel battery can cause bubbles in the electrolyte gel, and permanent damage."

In where you ask>
"One AGM and a normal wet cell charging one , it says it Supports GEL charging but there is no mode for tht - so should I go with the wet cell or AGM charging mode ?"

2+2 = 4 ya know .

[modernjack3]

This wasnt the second sentence - at least not on the Webpage you linked me but still thanks.

[GEuser]

This wasnt the second sentence - at least not on the Webpage you linked me but still thanks.

Oh i see , maybe paragraph then? , anyway what one can glean off that is normal WET , is it a big battery or just a small one , most i have played with (7AH TO 20AH) on the data printed on them say a terminal charge voltage of around 14.2 to 14.4 volt , and that's not the float voltage .

[modernjack3]

Well ist about 100 AH so quite big Id say - All Webpages say the perfet charging Voltage is between 14.2 and 14.4 V so I might just go with the normal Car battery Charge Mode since ist always under 14.4 Volt ^^ - but still I wonder at what Voltage I should cut off my devices so the Battery doesnt get destroyed / Damaged - I have read that at 12 Volts there is about 25% Charge lest which SHOULD be ok for a GEL cell but I might just go with 12.10 ? Does this Sound good or not?

[modernjack3]

So there is nobody who can help me out when it Comes to shutoff Voltage ? :S

[PChi]

The Yuasa web site has some good information at http://www.yuasa.co.uk/info/industrial-applications/installation-commissioning-and-maintenance-guide/

[tautech]

So there is nobody who can help me out when it Comes to shutoff Voltage ? :S

IMO you need to keep above 2.05v/cell.
Have a look at images in a Google search of: lead acid battery discharge curve.
Do understand that by the time the voltage roll off occurs battery capacity is almost depleted.

Yeah I know you have a Gel, it won't be vastly different.
Gel's also have a different max charge voltage for cyclic use as opposed to standby/float max charge voltage.

[modernjack3]

So my battery says 650 Wh with the Addition of that this is only effective when discharged over 20 hours - so does this mean that at this Point the battery is still "save" aka No worry about it getting destroyed ?

And is my Assumtion correct:
Max Amps = WH : 20 : 12
= 650 : 20 : 12 = 2.7 Amps?

[tautech]

So my battery says 650 Wh with the Addition of that this is only effective when discharged over 20 hours - so does this mean that at this Point the battery is still "save" aka No worry about it getting destroyed ?

And is my Assumtion correct:
Max Amps = WH : 20 : 12
= 650 : 20 : 12 = 2.7 Amps?

Yes, that's how I'd interpret the 20 hr discharge rate....2.7 A over 20 hrs.

How do you intend to monitor the discharge?

AFAIK the only point for knowing if a battery is discharged is a "no load" voltage and do remember that total usable capacity diminishes with age so you can't use a A/hr discharge calculation on an aged battery and not expect it to over-discharge the battery.
For light loads as the battery's internal resistances increases when discharged any of the battery monitoring IC's will give you warning as you near a preset threshold and allow disconnection or initiate charging.

For battery longevity you're best not use most of the available capacity ~2/3 should promote good life.

[modernjack3]

Sooo I jst realised that my "GEL" battery was a normal Acid - Lead battery all along and the guy in the store messed something up because he ensured me it was a GEL battery :/

...Now I found some Pictures as you said but they all kinda differ from each other ...
 I have got a Kemo Battery protector that id like to use so I might just take my 12 V Current source and calibrate 12 Volt as my shutdown voltage ? Do you think my battery will be happy with that - I got an ET650 ^^
... And is it OK when i make this 12V shutdown voltage under load ? I mean it can just be better for the battery since the voltage will just drop under load and not get higher , right?
Sadly I have no Idea how much the battery voltage moves around under load :/ so If you could help me out n this one Id be very happy !

Greetings , Jack

[tautech]

Sooo I jst realised that my "GEL" battery was a normal Acid - Lead battery all along and the guy in the store messed something up because he ensured me it was a GEL battery :/

It is a Gel, commonly know as a SLA but they do have different properties to a "flooded" cell battery.

I have got a Kemo Battery protector that id like to use

You need to find the voltage that it kicks in at.
Should be easy with an adjustable power supply and a DMM, there might even be an adjustment to tweak the protection level.

And is it OK when i make this 12V shutdown voltage under load ?

12V is too low IMO

Sadly I have no Idea how much the battery voltage moves around under load

It won't much at all with light loads until the battery nears full discharge and you don't want to operate it near full discharge, unless it's a "deep cycle" battery that's specifically made for that occasional scenario.

[modernjack3]

Well what voltage would you say is best then ? I have a buck boost conv Laying around tht i can use to adjust the shutdown voltage - tell me a Voltage and Ill use it...

[tautech]

Well what voltage would you say is best then ? I have a buck boost conv Laying around tht i can use to adjust the shutdown voltage - tell me a Voltage and Ill use it...

I've given an opinion and for you to learn more you can do some research will help understanding. 

Do some more Google'ing with this: minimum discharge voltage for SLA.

Tell us what you find so that it helps others. 

[GEuser]

Here is some stuff
http://www.energymatters.com.au/components/battery-voltage-discharge/

You probably have all the info by now though , the next issue is is a car type battery good enough for your circumstances but anyway 12V looks ok for a discharge voltage , bummer too on getting the wrong battery was it expensive? (like a gel price is normally dearer) ..

Edited>
One might have to take a look at derating curves/data also , now summer there but what happens in winter (snow/cold/inside/outside battery?) , the discharge voltage limit might change in the winter , just a thought .