Setting up different schedules of Equalisation with Lead acid batteries

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offgridsystems asked Nov 15, '18

Setting up different schedules of Equalisation with Lead acid batteries

I have a couple of customers who have Northstar AGM batteries on their small off grid systems. It seems from the Northstar data sheets they need equalisation every 2 weeks. Now we know the customer is never going to do the twiddly switch thing every two weeks (or even ever!), so was pleased to see the latest CCGX V2.20 firmware to include equalisation settings.

The only problem is, I cannot find anything pertaining to equalisation that I am able to initiate on the CCGX. Ticking the Equalisation box on VE Direct software is not quite enough as I'm unable to modify equalisation voltage or frequency of equalisation.

Any help greatly appreciated, as I am only able to equalise using a smart MPPT at the moment.

equalisation

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Answer 1 · 2018-11-15T19:51:34Z

howetec answered · Nov 15, 2018 at 07:51 PM

As far as I know the option currently uses Victrons default equalization settings, this will not work with the NorthStar batteries. Unfortunately there are not enough daylight hours in a day to carry out an equalisation using just the MPPT for this particular battery technology, from memory they need 16 hours at a fixed charge rate.

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Answer 2 · 2018-11-15T22:18:36Z

offgridsystems answered · Nov 15, 2018 at 10:18 PM

Hi Tom.. Thanks for the reply and you'll know very well the Northstar problem with Victron Equalisation. I have a couple of customers that are getting their Northstar's sulphated, or at least going high resistance and not coping with higher current draws any more... Typical of batteries not being equalised adequately. Just need a solution, even to alleviate the situation for them.

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howetec commented · Nov 16, 2018 at 06:23 PM

Hello..I think the only way is to carry out an equalisation to try to recover some capacity. You're going to need a generator and charger (especially this time of year), it's not going to happen with solar alone! Drop me an email or give me a buzz if you want to discuss.

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bmuk-tim commented · Dec 12, 2018 at 03:08 PM

An equalization charge is only required on the NorthStar Blue+ range of batteries if they are being used in a deep PSOC application.

If the batteries are getting a full recharge to 100% every day then a equlisation charge is not needed.

It might be worthwhile (during the winter months) reducing the depth of discharge for the batteries.

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Answer 3 · 2018-11-16T09:57:46Z

porcini answered · Nov 16, 2018 at 09:57 AM

In an offgrid pv-system you don't have the time to equalize a AGM correctly, like HOWETEC already said. That's the reason why a VRLA-Battery should never be used in a frequently used offgrid system. There are only two possibilities: Higher Voltage or a longer time of disuse.

It's a general problem, not a victron one.

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offgridsystems commented · Nov 16, 2018 at 11:02 PM

Thanks Porcini.. Yes, the AGM problem is the same with all off grid systems, however Victron seem to have very little way of controlling and customising the equalisation process. I'd like to be able to change EQ voltage, regularity, etc.. This is not possible right now unless the customer does that archaic switching thing when certain dates arrive on their calendar :)

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