Electrical Jayco Starcraft | Ritar 100Ah Deep Cycle GEL | How many volts is too low

Jared01

Active Member
Oct 28, 2016
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Sydney
Hello,

I have a 100Ah Ritar GEL battery in my Starcraft which has the Setec (III I believe) charger and 120w solar panel on the roof.

I always keep an eye on the battery voltage levels via the Solar Regulator and sometimes when using a combination of a bit of 12v TV and then now the Diesel Heater, the voltage gets down to 12.3 or 12.2 in the morning before the sun comes up.

I was trying to find a battery state of charge chart for a GEL battery, but there does not seem to be too many but did find this one: https://www.energymatters.com.au/components/battery-voltage-discharge/

Is getting my battery down to 12.3 or 12.2v too low?

How low do others usually get their battery voltage down to?


We are going to be using the caravan for a 3 week trip (heading away tomorrow) and will be on unpowered sites throughout the whole trip except maybe once.

I was thinking if 12.2v is a little low, I could start the car and give the batteries a little charge if required (although we will be driving a number of hours everyday and there is the solar too).



Just after some feedback.

Thank you!
 

achjimmy

Well-Known Member
Jan 24, 2011
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There ll be experts on here that can advise better but I seem to recall my cruiser spare battery used to safely go to 12.4 and then stay there a while
 

Boots in Action

Well-Known Member
Mar 13, 2017
1,446
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Ferny Grove, Queensland
Hello,

I have a 100Ah Ritar GEL battery in my Starcraft which has the Setec (III I believe) charger and 120w solar panel on the roof.

I always keep an eye on the battery voltage levels via the Solar Regulator and sometimes when using a combination of a bit of 12v TV and then now the Diesel Heater, the voltage gets down to 12.3 or 12.2 in the morning before the sun comes up.

I was trying to find a battery state of charge chart for a GEL battery, but there does not seem to be too many but did find this one: https://www.energymatters.com.au/components/battery-voltage-discharge/

Is getting my battery down to 12.3 or 12.2v too low?

How low do others usually get their battery voltage down to?


We are going to be using the caravan for a 3 week trip (heading away tomorrow) and will be on unpowered sites throughout the whole trip except maybe once.

I was thinking if 12.2v is a little low, I could start the car and give the batteries a little charge if required (although we will be driving a number of hours everyday and there is the solar too).



Just after some feedback.

Thank you!

Hi @Jared01 , just came across your post on battery voltages. A couple of things to start with: Firstly your Setec III will only charge to 14.0 volts from a 240 volt outlet and this is a very safe voltage for GEL batteries. However, if you have a look at the side of your Ritar Gel battery, you will see that the optimum charge voltage recommended by manufacturer is 14.2 to 14.4 volts. (at 25C) As the Setec III only gets to 14.0 volts, it will never get the max full charge capacity into the battery - perhaps only 85%?? Therefore soc voltage (and therefore storage capacity) for a FULLY charged battery?? will start off at a lower level. A reading of 12.3v or 12.2 volts UNDER MEDIUM LOAD is probably satisfactory in most cases. Please be aware that you will get no joy by trying to charge your van battery with the car alternator whilst driving unless you have a DC to DC charger. Most cars have an alternator charge output of 14.4 volts (some switch to a lower voltage to save power when car battery fully charged!!) and this voltage has to be transferred to the van battery. Even if you have minimal losses in the wiring - say only 0.2v, the current still has to go through a power diode before it gets to the SETEC for distribution to the battery. This power diode causes a further drop of 0.7 volts, so the best you could hope for getting to the battery would be 14.4 minus 0.2 minus 0.7 volts leaving you only 13.5 to maybe 13.6 volts to the battery. This voltage is NOT sufficient to put anywhere near full capacity into the battery to replace discharge already taken out and indeed is barely the "float" voltage. Depending on your solar controller, (brand not advised), you are probably getting around 14.4 volts whist charging and this is superior to trying to get the vehicle alternator to do the job - even better than the Setec if able to get lots of current from solar generation. If you can, have a look at the specs for your solar controller. However, if it is a Topraysolar, I think it has a fixed solar voltage charge of 14.4 to 14.7 volts. Let me know brand and I will be able to confirm settings.
I have also found a SOC chart for Gel batteries and will send that tomorrow for your info.
 

Boots in Action

Well-Known Member
Mar 13, 2017
1,446
1,279
113
Ferny Grove, Queensland
Hi @Jared01 , just came across your post on battery voltages. A couple of things to start with: Firstly your Setec III will only charge to 14.0 volts from a 240 volt outlet and this is a very safe voltage for GEL batteries. However, if you have a look at the side of your Ritar Gel battery, you will see that the optimum charge voltage recommended by manufacturer is 14.2 to 14.4 volts. (at 25C) As the Setec III only gets to 14.0 volts, it will never get the max full charge capacity into the battery - perhaps only 85%?? Therefore soc voltage (and therefore storage capacity) for a FULLY charged battery?? will start off at a lower level. A reading of 12.3v or 12.2 volts UNDER MEDIUM LOAD is probably satisfactory in most cases. Please be aware that you will get no joy by trying to charge your van battery with the car alternator whilst driving unless you have a DC to DC charger. Most cars have an alternator charge output of 14.4 volts (some switch to a lower voltage to save power when car battery fully charged!!) and this voltage has to be transferred to the van battery. Even if you have minimal losses in the wiring - say only 0.2v, the current still has to go through a power diode before it gets to the SETEC for distribution to the battery. This power diode causes a further drop of 0.7 volts, so the best you could hope for getting to the battery would be 14.4 minus 0.2 minus 0.7 volts leaving you only 13.5 to maybe 13.6 volts to the battery. This voltage is NOT sufficient to put anywhere near full capacity into the battery to replace discharge already taken out and indeed is barely the "float" voltage. Depending on your solar controller, (brand not advised), you are probably getting around 14.4 volts whist charging and this is superior to trying to get the vehicle alternator to do the job - even better than the Setec if able to get lots of current from solar generation. If you can, have a look at the specs for your solar controller. However, if it is a Topraysolar, I think it has a fixed solar voltage charge of 14.4 to 14.7 volts. Let me know brand and I will be able to confirm settings.
I have also found a SOC chart for Gel batteries and will send that tomorrow for your info.

Hi again @Jared01 , just found a picture of my daughter's failed Ritar Gel battery showing details on side. Saves you getting your battery out to check details. She now has a 130ah AGM for half the price of a replacement Ritar and it has a 2 year warranty - Ritar only has 12 months!!
 

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Boots in Action

Well-Known Member
Mar 13, 2017
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Ferny Grove, Queensland
Hi again @Jared01 , just found a picture of my daughter's failed Ritar Gel battery showing details on side. Saves you getting your battery out to check details. She now has a 130ah AGM for half the price of a replacement Ritar and it has a 2 year warranty - Ritar only has 12 months!!

Hello again @Jared01 and @achjimmy , seeing that I now have your attention, to help you understand a little more on this complex subject, please have a read of my post of June 14 on Solar # 1055. There are two references on that post to provide more info if you wish too. Also, the Setec III does not do my AGM battery any favours in charging as it requires 14.4 to 14.7 volts to enable full capacity to be achieved. I connect up my "smart" multi-stage charger to bring battery up to FULL capacity after being out off the grid, not the Setec. Setec III is great for permanent connection to battery as it will never overcharge and will look after the battery very well, but not the best for cyclic use to reach FULL capacity, and this lost capacity is never able to be recovered if left in less than FULL capacity on a regular basis or for long periods. This set out in references in my solar post.
 

Boots in Action

Well-Known Member
Mar 13, 2017
1,446
1,279
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Ferny Grove, Queensland
Hello again @Jared01 and @achjimmy , seeing that I now have your attention, to help you understand a little more on this complex subject, please have a read of my post of June 14 on Solar # 1055. There are two references on that post to provide more info if you wish too. Also, the Setec III does not do my AGM battery any favours in charging as it requires 14.4 to 14.7 volts to enable full capacity to be achieved. I connect up my "smart" multi-stage charger to bring battery up to FULL capacity after being out off the grid, not the Setec. Setec III is great for permanent connection to battery as it will never overcharge and will look after the battery very well, but not the best for cyclic use to reach FULL capacity, and this lost capacity is never able to be recovered if left in less than FULL capacity on a regular basis or for long periods. This set out in references in my solar post.

@Jared01 , I had a search around for a soc voltage chart for a gel battery and I think this one will suit you. It is almost the same as an AGM. Whilst an AGM is fully charged to 100%, the voltage will be 13.0 volts. A gel is not charged to such a high voltage and would normally be considered 100% charged at 12.6 or 12.7 volts. All readings are after at least 1 hour or longer AFTER battery is off charge and without any load at all. I hope you find it useful and I have also included a note about what happens if a battery is not fully charged up to 100% capacity every time. Interesting reading. Also set out is the site where a lot of this info is available on Google which shows a lot of data.

gel battery soc voltage
 

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