Quick and maybe dumb question about max charging volts

[Narrowboat boy]

Hi Larry

Did that originally but that resulted in a much larger voltage hike than it should be for the current temperature of the bank see earlier in thread .. The You Tube tutorial number 4 I think it is by Ryan at midnite solar says set to -0.5 for 5 mv per cell compensation so you can see how confused I am , if I set it at -0.5 ( it wont allow -0.4 ) then the compensated voltage is much closer to what I would expect to see for my bank at the current temperature so something is awry

[boB]

-5.0 should be -5.0 mV per degree C per 2V cell.

Not sure where -0.5 comes from ?    I will look at the video.

Thanks NBB !

Not so narrow boB

[Narrowboat boy]

Thanks boB vid is def confusing .

Also another quick question if I may what should I set the max volts at as temp compensation could take absorb voltage over 15v if temp falls to low single digits in winter which it can. This seems scarey high for agms . Manufacturer don’t give a max number other than a absorb range . What is typical max for agms

Cheers

[ClassicCrazy]

Thanks boB vid is def confusing .

Also another quick question if I may what should I set the max volts at as temp compensation could take absorb voltage over 15v if temp falls to low single digits in winter which it can. This seems scarey high for agms . Manufacturer don’t give a max number other than a absorb range . What is typical max for agms

Cheers

You need to charge the battery higher voltage if it is cold - as long as you are following temp compensation from manufacturer you shouldn't  have to worry about the  max voltage during absorb for cold batteries.
read info here for reference
https://rollsbattery.com/wp-content/uploads/2018/01/Rolls_Battery_Manual.pdf
Larry

[boB]

AGMs usually have a maximum and minimum Absorb voltage listed in their specifications.   This is the reason that there is a MAX and MIN Temp-Comp voltage limits available in the Classic.

Flooded lead acid is a wider range of voltage typically.

Maybe your AGM manufacturer left that part out of their specs ?  I would look a bit closer maybe. I have found those numbers hard to find some times.

Or let us know what kind of batteries you have.   Oh, I see    5 x Victron 110 Ah Deep Cycle AGM Batteries

I didn't know that Victron made batteries.

[Narrowboat boy]

Hi boB

Yes Victron make excellent batteries and have a big range but I think they may only be available in Europe I dont see them discussed in any USA forums along with their solar panels etc which are also good ( though I dont use them as they are more focussed on smaller array applications than mine .

The Absorb range for the Victron Deep Cycle AGM's is 14.2 to 14.6 v in normal service and 14.6 -14.9 for fastest charging service . So should I set the max to 14.6 v ? I have set absorb to 14.3 as batteries are about 9 months old . Does this sound about right or should I be setting the max closer to the fast charge max ? , They dont give a specific temperature compensated max .

Simon

[ClassicCrazy]

Hi boB

Yes Victron make excellent batteries and have a big range but I think they may only be available in Europe I dont see them discussed in any USA forums along with their solar panels etc which are also good ( though I dont use them as they are more focussed on smaller array applications than mine .

The Absorb range for the Victron Deep Cycle AGM's is 14.2 to 14.6 v in normal service and 14.6 -14.9 for fastest charging service . So should I set the max to 14.6 v ? I have set absorb to 14.3 as batteries are about 9 months old . Does this sound about right or should I be setting the max closer to the fast charge max ? , They dont give a specific temperature compensated max .

Simon

Really all AGM batteries share the same chemistry and usually there are only a few battery manufacturers and they sell their batteries to be rebranded by others. I highly doubt Victron has their own battery factory.
(Look on your batteries and see where they are made )
If you don't charge the batteries up properly when they are cold you will ruin them because you will think they are charged but they really aren't. There is no way to take SG reading on an AGM to confirm anything .
When they are cold they aren't going to get hot and vent so higher voltages on cells aren't the same as when they are hot.
I suggest you do some research on other manufacturers detailed specs and maintenance given for their AGM cells .
I learned my lesson early in my solar days with not charging a flooded type  cold battery properly and ruining it.

Larry

[boB]

Simon, you might want to chat with the fine folks at Victron about the battery specifications and what they should see for limits, etc.

These folks are good people.   I met the founder/designer and his son while at Intersolar in Munich a few years ago.  His son I believe is now running the place while dad works on some new designs. 

[Narrowboat boy]

Hi boB

Yes Victron make excellent batteries and have a big range but I think they may only be available in Europe I dont see them discussed in any USA forums along with their solar panels etc which are also good ( though I dont use them as they are more focussed on smaller array applications than mine .

The Absorb range for the Victron Deep Cycle AGM's is 14.2 to 14.6 v in normal service and 14.6 -14.9 for fastest charging service . So should I set the max to 14.6 v ? I have set absorb to 14.3 as batteries are about 9 months old . Does this sound about right or should I be setting the max closer to the fast charge max ? , They dont give a specific temperature compensated max .

Simon

Really all AGM batteries share the same chemistry and usually there are only a few battery manufacturers and they sell their batteries to be rebranded by others. I highly doubt Victron has their own battery factory.
(Look on your batteries and see where they are made )
If you don't charge the batteries up properly when they are cold you will ruin them because you will think they are charged but they really aren't. There is no way to take SG reading on an AGM to confirm anything .
When they are cold they aren't going to get hot and vent so higher voltages on cells aren't the same as when they are hot.
I suggest you do some research on other manufacturers detailed specs and maintenance given for their AGM cells .
I learned my lesson early in my solar days with not charging a flooded type  cold battery properly and ruining it.

Larry

Thanks Larry they are made in Vietnam so you are probably right , they are very good batteries however . boB I have asked on the forum but unlike this one Victron staff are not very present on it so we will see what answer I get .

[ClassicCrazy]

Hi boB

Yes Victron make excellent batteries and have a big range but I think they may only be available in Europe I dont see them discussed in any USA forums along with their solar panels etc which are also good ( though I dont use them as they are more focussed on smaller array applications than mine .

The Absorb range for the Victron Deep Cycle AGM's is 14.2 to 14.6 v in normal service and 14.6 -14.9 for fastest charging service . So should I set the max to 14.6 v ? I have set absorb to 14.3 as batteries are about 9 months old . Does this sound about right or should I be setting the max closer to the fast charge max ? , They dont give a specific temperature compensated max .

Simon

Really all AGM batteries share the same chemistry and usually there are only a few battery manufacturers and they sell their batteries to be rebranded by others. I highly doubt Victron has their own battery factory.
(Look on your batteries and see where they are made )
If you don't charge the batteries up properly when they are cold you will ruin them because you will think they are charged but they really aren't. There is no way to take SG reading on an AGM to confirm anything .
When they are cold they aren't going to get hot and vent so higher voltages on cells aren't the same as when they are hot.
I suggest you do some research on other manufacturers detailed specs and maintenance given for their AGM cells .
I learned my lesson early in my solar days with not charging a flooded type  cold battery properly and ruining it.

Larry

Thanks Larry they are made in Vietnam so you are probably right , they are very good batteries however . boB I have asked on the forum but unlike this one Victron staff are not very present on it so we will see what answer I get .

I would look up  Vietnam AGM battery manufacturers - they all have websites with photos of their products. Then look for one with AGM case and printing on it that looks like what you have. They may have more detailed info on their webpage or  email  them directly and a technician there might give you the info you want. I did a quick look  and some of the Vietnam battery manufacturers are branch factories of some large Asian battery manufacturers.
Good luck !

Larry