GEL Battery questions.. - Page 1
Forum section: electronics / beginners

author: modernjack3
author_rank: Contributor
timestamp: July 02, 2016, 03:13:22 pm
content: 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 eitherSo 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 !

author: GEuser
author_rank: Frequent Contributor
timestamp: July 02, 2016, 03:40:49 pm
content: http://www.chargingchargers.com/tutorials/charging.html2nd sentence .

author: modernjack3
author_rank: Contributor
timestamp: July 02, 2016, 03:43:44 pm
content: Quote from: GEuser on July 02, 2016, 03:40:49 pmThese are the "smart chargers", and quality units generally are not found in discount stores.This is no help at all man...

author: GEuser
author_rank: Frequent Contributor
timestamp: July 02, 2016, 03:54:40 pm
content: Quote from: modernjack3 on July 02, 2016, 03:43:44 pmIn 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 .

author: modernjack3
author_rank: Contributor
timestamp: July 02, 2016, 03:59:12 pm
content: This wasnt the second sentence - at least not on the Webpage you linked mebut still thanks.

author: GEuser
author_rank: Frequent Contributor
timestamp: July 02, 2016, 04:05:59 pm
content: Quote from: modernjack3 on July 02, 2016, 03:59:12 pmOh 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 aterminalcharge voltage of around 14.2 to 14.4 volt , and that's not the float voltage .

author: modernjack3
author_rank: Contributor
timestamp: July 02, 2016, 04:21:31 pm
content: 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?

author: modernjack3
author_rank: Contributor
timestamp: July 02, 2016, 08:37:52 pm
content: So there is nobody who can help me out when it Comes to shutoff Voltage ? :S

author: PChi
author_rank: Frequent Contributor
timestamp: July 02, 2016, 09:20:16 pm
content: The Yuasa web site has some good information athttp://www.yuasa.co.uk/info/industrial-applications/installation-commissioning-and-maintenance-guide/

author: tautech
author_rank: Super Contributor
timestamp: July 02, 2016, 09:39:43 pm
content: Quote from: modernjack3 on July 02, 2016, 08:37:52 pmIMO you need to keep above 2.05v/cell.Have a look atimagesin 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.

author: modernjack3
author_rank: Contributor
timestamp: July 02, 2016, 10:00:25 pm
content: 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?

author: tautech
author_rank: Super Contributor
timestamp: July 02, 2016, 10:18:33 pm
content: Quote from: modernjack3 on July 02, 2016, 10:00:25 pmYes, 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.

author: modernjack3
author_rank: Contributor
timestamp: July 02, 2016, 11:23:16 pm
content: 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

author: tautech
author_rank: Super Contributor
timestamp: July 02, 2016, 11:44:00 pm
content: Quote from: modernjack3 on July 02, 2016, 11:23:16 pmIt is a Gel, commonly know as a SLA but they do have different properties to a "flooded" cell battery.QuoteYou 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.Quote12V is too low IMOQuoteIt won't much at all with light loadsuntilthe 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 thatoccasionalscenario.

author: modernjack3
author_rank: Contributor
timestamp: July 02, 2016, 11:51:32 pm
content: 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...

author: tautech
author_rank: Super Contributor
timestamp: July 03, 2016, 12:33:59 am
content: Quote from: modernjack3 on July 02, 2016, 11:51:32 pmI'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.

author: GEuser
author_rank: Frequent Contributor
timestamp: July 03, 2016, 01:54:04 am
content: Here is some stuffhttp://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 .