How many AMPS is to much for AGM battery (20 Viewers)

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Aug 24, 2022
93
53
Funster No
90,846
MH
Autotrail savannah
Exp
2020
Good evening all
Hope you can help!
I have 2 agm batts wired in parallel give a total of 190amps combined.
I’m fitting a 12/12/50 Victron xs which you know has a variable voltage setting.
I intend to get the full potential of this when I get my lithium.
Question is what could I set the max charge current to on the xs so the fitted agm’s get as much as they can but don’t cause the batteries damage.
 
Jan 25, 2024
158
229
North Norfolk, UK
Funster No
100,876
MH
Bailey Approach 745
Exp
since 2012
I think you have two batteries each is 95 Amp Hours. Not Amps.

That gives you 190 Amp Hours capacity of which you maybe have half, that is 95 Amp Hours available. That is probably ten Amps for about nine and a half hours but it is never as straightforward as that!

Find out the manufacturer of the AGM batteries and ask them. It can be quite maker specific.
If you want a rate that won’t worry anything, use 20 amps.

Try to think in Amp Hours and Watts!

Tony
 
OP
OP
garysavannah
Aug 24, 2022
93
53
Funster No
90,846
MH
Autotrail savannah
Exp
2020
I think you have two batteries each is 95 Amp Hours. Not Amps.

That gives you 190 Amp Hours capacity of which you maybe have half, that is 95 Amp Hours available. That is probably ten Amps for about nine and a half hours but it is never as straightforward as that!

Find out the manufacturer of the AGM batteries and ask them. It can be quite maker specific.
If you want a rate that won’t worry anything, use 20 amps.

Try to think in Amp Hours and Watts!

Tony
Sure 👌 that’s 10 amps going to each doesn’t sound a lot, yuasa for some reason don’t give any useful info out on this battery and many others have said the same even with contacting them they’ve had no reply, not sure why.
 
OP
OP
garysavannah
Aug 24, 2022
93
53
Funster No
90,846
MH
Autotrail savannah
Exp
2020
I think you have two batteries each is 95 Amp Hours. Not Amps.

That gives you 190 Amp Hours capacity of which you maybe have half, that is 95 Amp Hours available. That is probably ten Amps for about nine and a half hours but it is never as straightforward as that!

Find out the manufacturer of the AGM batteries and ask them. It can be quite maker specific.
If you want a rate that won’t worry anything, use 20 amps.

Try to think in Amp Hours and Watts!

Tony
 
OP
OP
garysavannah
Aug 24, 2022
93
53
Funster No
90,846
MH
Autotrail savannah
Exp
2020
What would be the amps of this battery if the 95 referenced ah not amps!

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Jan 25, 2024
158
229
North Norfolk, UK
Funster No
100,876
MH
Bailey Approach 745
Exp
since 2012
You aren’t really interested in amps unless wanting to load it with, say, an inverter.
If it’s a starting battery you want to know Cold Cranking Amps, is this what you are asking?

Where there two batteries fitted from new?
By a professional?

How are they wired together?

How is the output taken?

Tony
 
OP
OP
garysavannah
Aug 24, 2022
93
53
Funster No
90,846
MH
Autotrail savannah
Exp
2020
You aren’t really interested in amps unless wanting to load it with, say, an inverter.
If it’s a starting battery you want to know Cold Cranking Amps, is this what you are asking?

Where there two batteries fitted from new?
By a professional?

How are they wired together?

How is the output taken?

Tony
Understand inverter going in when lithium batt is installed but not on this agm set up so I guess it was just a loose question as I assumed all batteries have an amp rating, I’m learning all the time 🙂
Both batteries have been installed from new by me along with a 400 watts Victron solar charge controller system all has been great with this agm setup for 2 years
I’m in the process of getting away from the Sargent out dated system on the motorhome and the b2b is the next step towards that, albeit the lithium will be the last thing to go in.
My final setup will look like attached image and still some wreaking to do so drawing not finalised.
The two agms are wired in parallel negs connect together and pos connected together then feed from pos from one battery and neg from the other going into vehicle. Hope this makes sence



IMG_0653.jpeg
 

funflair

LIFE MEMBER
Dec 11, 2013
20,180
33,834
Guisborough
Funster No
29,351
MH
MORELO palace
Exp
since 2012
What would be the amps of this battery if the 95 referenced ah not amps!
The battery is rated at a nominal voltage and capacity, the voltage will be 12v and the capacity is stated in ah (amps per hour) in your case 95ah means that it can supply 9.5 amps for 10 hours BUT then it will be completely discharged and therefore dead and will most likely stay dead, for longevity you should not go below 50% capacity, the only time amps would come into it would be if the manufacturer of the battery stated a maximum draw in amps, or indeed a maximum charge rate which I believe is what you were asking in the first place.

EDIT sorry I think I have basically repeated what Jabstatt posted 45 mins ago ;)
 
OP
OP
garysavannah
Aug 24, 2022
93
53
Funster No
90,846
MH
Autotrail savannah
Exp
2020
The battery is rated at a nominal voltage and capacity, the voltage will be 12v and the capacity is stated in ah (amps per hour) in your case 95ah means that it can supply 9.5 amps for 10 hours BUT then it will be completely discharged and therefore dead and will most likely stay dead, for longevity you should not go below 50% capacity, the only time amps would come into it would be if the manufacturer of the battery stated a maximum draw in amps, or indeed a maximum charge rate which I believe is what you were asking in the first place.

EDIT sorry I think I have basically repeated what Jabstatt posted 45 mins ago ;)
Yes it was 🙂 absolutely understand what your saying 👍
 
Jan 25, 2024
158
229
North Norfolk, UK
Funster No
100,876
MH
Bailey Approach 745
Exp
since 2012
That set up looks great.
On the AGM charging, maybe suck it and see?
Try 40 and check they stay cool.
If you are replacing anyway, bu@@@@ing them means new toys earlier!
Grin.

Tony

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OP
OP
garysavannah
Aug 24, 2022
93
53
Funster No
90,846
MH
Autotrail savannah
Exp
2020
That set up looks great.
On the AGM charging, maybe suck it and see?
Try 40 and check they stay cool.
If you are replacing anyway, bu@@@@ing them means new toys earlier!
Grin.

Tony
Thanks Tony 🙂
It’s been suggested that I use the C/5 principle capacity divided 5 giving 38 amp charge so your 40 amp suggestion is not far away, I still remain a little nervous as have had some conflicting advice some say low some say much more can be used.
 
OP
OP
garysavannah
Aug 24, 2022
93
53
Funster No
90,846
MH
Autotrail savannah
Exp
2020
I think the OP is asking what the maximum CHARGE current should be not the useable capacity.
I would suggest at least 15A for each battery, i.e. 30A from the 12 12 50.
Your correct Rod your suggestion makes sence and is below the C5 rule 👍
 
OP
OP
garysavannah
Aug 24, 2022
93
53
Funster No
90,846
MH
Autotrail savannah
Exp
2020
That set up looks great.
On the AGM charging, maybe suck it and see?
Try 40 and check they stay cool.
If you are replacing anyway, bu@@@@ing them means new toys earlier!
Grin.

Tony
Absolutely love new toys on the motor home 😅
 

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