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tony-m avatar image
tony-m asked

Charge settings - can't find for my battery

I hope someone can give me some direction. I've really been trying to find the answer to this.

I have four 50W Solar panels in parallel on my van roof and I'm trying to enter settings for my Victron 100|20 MPPT to charge an AGM battery. I know that I should follow the manufactures recommended settings, but problem is that I can't find those settings. Can someone advise me?

I'm trying to charge a Varta Silver Dynamic Agm G14 12V 95Ah 850A. I realize this is not the ideal battery for a solar system, but I'm only using this battery temporarily as I save up for a lithium phosphate battery bank. I bought it because it is the exact same type that came with my Sprinter and that way I can use it as a replacement when my van battery dies.


The only preset I see in the Victron app says AGM spiral - it's not clear to me that applies to my battery


This page gives a nice plot, but it's not clear it applies to my battery

https://www.varta-automotive.com/bg-bg/Поддръжка/charging/how-to-charge-a-car-battery

Here is the link to where I bought the battery:

https://www.amazon.fr/gp/aw/d/B01N2VO2OI?psc=1&ref=ppx_pop_mob_b_asin_image

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4 Answers
Alexandra avatar image
Alexandra answered ·

@Tony M

Are there no info stickers on the battery?

It is designed for use in a car, car alternator voltages should be ok. So 14.6v bulk/absorption and 13.2v float? Car alternators are not exact chargers.

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tony-m avatar image
tony-m answered ·

@Alexandra thanks for the quick response. I see no "stickers on the battery" - and when I received it from Amazon, there was no manual. Here's a photo I took just now:

img-0436.jpeg

Since those numbers are hard to see, I've typed it out below along with other info I've gathered:

Varta Silver Dynamic Agm G14 12V 95Ah 850A (EN) 595 901 085 D85 2 and has this code stamped at the top right: Z8G277242 0296. It also has RC: 160 min, with this code: A 001 982 82 08, here is a link to it:

https://www.varta-automotive.com/en-gb/battery-finder?battery_code=A+001+982+82+08&find=find


img-0436.jpeg (792.9 KiB)
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kevgermany avatar image kevgermany ♦♦ commented ·
Don't over discharge this or run high currents for long periods. Maybe keep it to 75% charged or higher.
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tony-m avatar image tony-m kevgermany ♦♦ commented ·

@Alexandra and @kevgermany -- very nice of you to help out - I appreciate the advice. I have gone ahead and started charging using the "AGM spiral" setting, and it seems to be charging fine.

As I said, this is a temporary situation until I can afford the proper battery bank and other solar panels. But in the meantime, it's nice to have a way to use the van with some power.

I actually have another source of power: an EB55 Power Station - but unfortunately that did not have whatever it takes to start up my Truma heater and that's why I got the Varta AGM battery

I welcome any other advice. Thanks again.

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Alexandra avatar image
Alexandra answered ·

@Tony M

Yeah, I looked. There is definitely no help online, even their tech specs are just dimensions.

The AGM profile should be fine for it. The profile will have what us needs lile temperature compensation.

It is more likely to have reduced life due to cycling since it is not exactly designed for that.

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tony-m avatar image
tony-m answered ·

@Alexandra @kevgermany I have one more question:


With this type battery is it best to keep it connected to the solar panels (via MPPT 100|20) all the time, even when not in use?

I ask because you mentioned treating this battery gently as it's not intended for deep cycle use. I'm only using it to power a 12V Truma D6 diesel heater, which according to the manufacturer consumes 1.8 – 4 A, 22-48W -- the only hard part being getting it started. They say it's < 1.8 A in normal use between "Off" and "low”

I've added a video of the charging I've done so far -- haven't added a load yet


mppt.mp4 (360.5 KiB)
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Alexandra avatar image Alexandra ♦ commented ·

@Tony M

Keeping it on float should be ok.

Depth of discharge is more of a concern.

If you are using the heater mainly with solar then it should be fine.

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