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  1. #1
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    Default Charging Gel Batteries - 220v/Alternator/Solar Considerations

    I've just discovered that I can get hold of Exide Gel batteries. I've never used gel before and I'm keen to entertain them as an option. However I understand the dangers of frying them by over-charging. I need to get my head around four areas and am hoping someone could just confirm I have this right:

    1. Mastervolt 12/40 240v mains charger
    My Mastervolt 12/40 mains charger has some jumpers I swap over to compensate for gel charging though it seems to group together gel/wet battery as one option, with the other two being 'forced float' and 'diode compensation'. The instruction manual says 'by removing the gel/wet battery jumper the output will be a constant 'trickle charge' voltage of 13.8v. I understand gel batteries are floated at a higher rate (13.8). So, assuming I find the following jumpers am I to remove the top one in the middle column?



    2. Sterling Pro AltC Split Charger
    This is a simple rotary function switch I turn to 'gel. However it appears to split these into US Spec and EU Spec. What is this and how can I determine which the gels from India fall in to?

    Also, I now have a sealed lead-acid starter battery and gel house. Does this unit handle the different batteries?

    3. Balmar Alternator Regulator
    I've yet to purchase this but I am sure I'm able to set the paramters for gel ok.

    4. Steca PR 2020 Solar Regulator
    I have http://www.stecasolar.com/index.php?Steca_PR_10_30_enas my solar regulator and there is an option to set this for 'gel', so I'm hoping I'm ok here.

    Are there any other considerations I have forgotten?

  2. #2
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    Default

    It is dangerous to generalise too much about batteries. Different makes and models even of nominally similar types do have different charging requirements. If in doubt go by what the battery manufacturer says not the charger manufacturer. Some charger manufacturers have some odd ideas! (My Cristec charger has some absolutely ludicrous output options.)

    However it's not too much generalisation to say you need to take great care if you mix SLA and gel. Their charging requirements will be different. You will need separately controlled outputs to handle them decently. It's easier to mix SLA and wet or gel and wet because wets are more tolerant.

    On your charger, US spec probably means lead-calcium and EU spec probably means lead-antimony. It is probably a slightly higher voltage setting on US than on EU. If the gel batteries are Exide India then they are more likely to be antimony than calcium, so probably EU setting - but you really need to know Exide's recommendation and compare it with the charger figures.

    So sorry, I can't answer your questions definitively. Nobody can without detailed knowledge of the hardware and batteries you have got, and i know that detailed info can be hard to get hold of.

  3. #3
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    vyv_cox is offline Registered User
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    Default

    I would not dispute that what Troubadour says is exactly right. However, I had until very recently three open cell acid domestic batteries and an AGM starter battery. All are charged by either my Sterling controller on the lead acid setting or by my solar panel controller that has no variable settings. The mains charger normally only charges the domestic bank but can be used for the starter. I am careful not to charge the AGM for excessive lengths of time but despite the poor charging treatment it receives it remains in good health. It is now three or four years old and seems fine. The open cell batteries have been replaced by sealed ones and the Sterling settings changed appropriately, which should give the AGM an easier time.
    Answers to some technical queries at http://coxengineering.sharepoint.com

  4. #4
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    Quote Originally Posted by vyv_cox View Post
    I would not dispute that what Troubadour says is exactly right. However, I had until very recently three open cell acid domestic batteries and an AGM starter battery. All are charged by either my Sterling controller on the lead acid setting or by my solar panel controller that has no variable settings. The mains charger normally only charges the domestic bank but can be used for the starter. I am careful not to charge the AGM for excessive lengths of time but despite the poor charging treatment it receives it remains in good health. It is now three or four years old and seems fine. The open cell batteries have been replaced by sealed ones and the Sterling settings changed appropriately, which should give the AGM an easier time.
    Yes I'm counselling perfection and you may get away with less! Also peoples' batteries are often in a much worse state than they think they are; they only notice when they suddenly have to call for a deeper than habitual discharge and find they can't get it.
    AGMs are terrific as starter batteries and if as oversized as small yacht batteries normally are, will do the job even if in much less than ideal condition. What will kill most AGMs is if you have more than about 14.4V for a lot of the time. You probably don't.

  5. #5
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    Also peoples' batteries are often in a much worse state than they think they are
    So, so true. Sadly most of what you say is moot as I cannot get hold of AGMs, as I think I have said before. I could ship them in but that would cost a fortune.

    Since you're here, personal opinions on sealed lead-acid versus gel for domestic? I know the basic benefits and differences but has anyone had any experience of gel? I've just received the usual curt response from Charles Sterling who says
    gel and sealed charge at the same profile so there is no problem, however i would not use gel batteries as the are over sold, expensive and useless
    The price I have for 100aH gels are about GBP120.

  6. #6
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    I wouldn't be quite as outspoken as Mr Sterling but I'd only consider gel if I couldn't get a flooded battery or if I was paranoid about leakage and couldn't get an AGM!
    As I said before "Some charger manufacturers have some odd ideas!"
    I still find it hard to believe any SLA will give the same life as a GOOD wet battery but some reports are good and I admit there have been design advances since I left the industry. At the time ours were top of the market and BT approved supposedly with a 10 year life (standby not cycling) but ...
    A high temperature environment leans me even more towards wets.
    There is an Exide India subsidiary that does make SLA batteries
    http://www.sfindustrial4u.com/ no idea how good.

  7. #7
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    OK, I'm confused now. I understood gel batteries as being a great solution for the marine environment from what I've read. I've also read, however, conflicting reports on gel and their performance in higher temperature environments, but they can be cycled 1,000 times, versus 300 or so for SLA. Considering that I'm looking for the convenience of a maintenance-free solution, why should I avoid gel?

  8. #8
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    Flooded batteries range from cheap thin plate starter batteries that will give you a rotten cycling life through to expensive heavy duty ones with a good cycle life.
    Gel batteries range from cheap thin plate fire alarm batteries that will give you a rotten cycling life through to expensive heavy duty ones with a good cycle life.
    AGM batteries range from cheap thin plate starter or fire alarm batteries that will give you a rotten cycling life through to expensive heavy duty ones with a good cycle life.

    I don't know what you're looking at and whose claims you are believing. 1,000 cycles under what conditions?

    Gel have to be discharged with care and recharged with care (and generally slower than other types) and if you get it wrong they are ruined. AGM also needs some care but can be recharged quickly. Wet are the most robust.

    High temperatures are bad for any lead acid battery but they particularly exacerbate the charging fussiness of gel and SLA.

    Is topping up occasionally really intolerable?

    How long are you staying in India? Long enough to try and claim under warranty if the expensive gel ones don't last?

  9. #9
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    Quote Originally Posted by Troubadour View Post
    I don't know what you're looking at and whose claims you are believing. 1,000 cycles under what conditions?

    Is topping up occasionally really intolerable?

    How long are you staying in India? Long enough to try and claim under warranty if the expensive gel ones don't last?
    I've no idea of the conditions of the cycles. This is half the problem with researching battery manufacturers I've never heard of before (Indian). What I have read is that the SLA batteries here have been designed with the tropical environment in mind.

    Dare I admit it but I once had open lead-acid non-branded truck batteries and they lasted me less than two seasons. In order to fit them in my boat one had to be placed in a really difficult area to access (a low cupboard) and was nigh on impossible to check properly. As a result I was never able to top them up efficiently. Whilst many people using this forum have grown up with lead acid batteries, I find them a hassle (I've owned one car in my life and that was for two years only). I'm prepared to pay a little extra, or lose one year's worth of battery life, for the sake of a maintenance-free solution.

    I appreciate your comments, Troubadour, and as a consequence of your comments, Sterling's and my research I think gel are now out the window, at least whilst in India. This thread may appear inconclusive but you've helped me thrash out some ideas and force me to do some research.

    It seems, however, that my original claim that AGMs are not available in India is not true. I have found a manufacturer with an outlet in Cochin and yes, I'll be here long enough to ensure they last longer than the warranty. However if they prove to be too expensive I'll probably just settle for SLA once more and just be aware that I may have to change them again in three years time. As usual this is a price/performance compromise scenario with tight budgetary constrainsts. I only entertained the gel option as they appeared to be very cheap by European standards.

    So, possibility of AGMs or back to SLAs manufactured for the tropical environment. Either way I think I need to spend more of my energy in solving an efficient charging circuit because that has been the main cause of my woes.

  10. #10
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    Quote Originally Posted by demonboy View Post
    I've just discovered that I can get hold of Exide Gel batteries. I've never used gel before and I'm keen to entertain them as an option. However I understand the dangers of frying them by over-charging. I need to get my head around four areas and am hoping someone could just confirm I have this right:

    1. Mastervolt 12/40 240v mains charger
    My Mastervolt 12/40 mains charger has some jumpers I swap over to compensate for gel charging though it seems to group together gel/wet battery as one option, with the other two being 'forced float' and 'diode compensation'. The instruction manual says 'by removing the gel/wet battery jumper the output will be a constant 'trickle charge' voltage of 13.8v. I understand gel batteries are floated at a higher rate (13.8). So, assuming I find the following jumpers am I to remove the top one in the middle column?



    2. Sterling Pro AltC Split Charger
    This is a simple rotary function switch I turn to 'gel. However it appears to split these into US Spec and EU Spec. What is this and how can I determine which the gels from India fall in to?

    Also, I now have a sealed lead-acid starter battery and gel house. Does this unit handle the different batteries?

    3. Balmar Alternator Regulator
    I've yet to purchase this but I am sure I'm able to set the paramters for gel ok.

    4. Steca PR 2020 Solar Regulator
    I have http://www.stecasolar.com/index.php?Steca_PR_10_30_enas my solar regulator and there is an option to set this for 'gel', so I'm hoping I'm ok here.

    Are there any other considerations I have forgotten?
    I would look up the manufactures recomendations they do vary quite a bit between brands. When you have the correct bulk and float voltages (dont forget to compensate for temperatue) I would use a multimeter (with fresh batteriey in it, or even better a couple of multimeters) and see which settings give you closest to the required voltages.
    I have Sonnenschein gel batteries and have had great life (16 years in one and 10-12 in the other). The sonnenschein web site has very detailed charging instructions Exide have taken them over and the Exide gels physically look similar (but they may be very different inside the casing)

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