Mixing Battery types in 1 Bank

[Andina Marie]

Originally Posted by colemj

Mixing flooded and AGM's can probably be done with impunity since their charging profiles are so similar and one almost never gets to the higher voltages that flooded will take for very long.

Mixing flooded with gel is a different story. I am surprised Andina didn't check herself on that post. If we mixed gel with flooded on our boat, we would surely ruin the gels within a couple of weeks, as the charge profile for our flooded batteries is an absorption voltage of 14.8V and we reach that often.

<SNIP>

Mark

Perhaps you didn't read my original post

The only thing to watch would be the setting on a charger that allowed choice of battery type, in which case you should select one that is compatible with the most sensitive parameter, typically maximum voltage.

At a safe voltage for the gel batteries the flooded batteries will still get a full charge, on average it means about 5 minutes more at the lower voltage.

[colemj]

Originally Posted by Andina Marie

Perhaps you didn't read my original post
At a safe voltage for the gel batteries the flooded batteries will still get a full charge, on average it means about 5 minutes more at the lower voltage.

Fair enough - I understood it better with another reading.

However, continually charging a deep cycle flooded battery at 14-14.2V will result in more rapid sulfation of it. And there isn't really a convenient way to equalize part of a bank regularly. Trojan really stresses 14.8V for their batteries, for example.

Mark

[sailinglegend]

Originally Posted by Andina Marie

....At a safe voltage for the gel batteries the flooded batteries will still get a full charge, on average it means about 5 minutes more at the lower voltage.

This is very bad advice - again - from someone who has been in the business for so long!

Any battery can get fully charged at even 13.2 volts, BUT they will not charge properly, and as colemj says they WILL sulphate and die prematurely.

Batteries need to reach their 'gassing voltage' when charging to help burn off the lead sulphate that forms as part of the discharge process. So the proper charging voltage is essential, and that is not always provided by the pre-sets available. Best practice is to have chargers that allow custom settings for absorption and float voltages - and follow the manufacturers recommendations.

_________
Ignorance isn't what you don't know, it's what you think you know that is incorrect.

[TeddyDiver]

Smells like dead batteries very soon, of course if the boat is used only 6 hours every few months it doesn't really matter just float charging and they die of old age before any real damage been done.
Just out of curiosity, why?

[monte]

just to clarify, the boat is new, the batteries are new, the boat will be permanently running from the batteries charged via 1120W of solar. The 560Ah installed is a little on the low side for the power budget and solar capacity so I want to increase it to around 800Ah to give us 360Ah usable between charges. With fridge/autopilot/wm/nav gear consumption would be around 15A so we could run for 24hrs with no charging. I know the current bank would be ample for when at anchor, but I would like it to work when on 20-30 day passages without having to run engines.

[belizesailor]

Wow, 1120W of solar and you're going with low end batteries? I suggest another strategy: invest in a complete good quality battery bank and sell off those "maintenance free" (AKA "impossible to maintain as needed" ) batteries.

Good quality, properly maintained batteries can last a long time. My house bank is now 10 years old and going strong. As often stated, batteries don't die, they are murdered. Mixing chemistries is just another creative way to murder batteries. And "cheap" batteries are false economy.

You do have a good solar regulartor right?

[belizesailor]

Originally Posted by sailinglegend

...
_________
Ignorance isn't what you don't know, it's what you think you know that is incorrect.

Great signature! That could be the subtitle for Cruiser's Forum! ;-)

[TeddyDiver]

Originally Posted by belizesailor

Wow, 1120W of solar and you're going with low end batteries? I suggest another strategy: invest in a complete good quality battery bank and sell off those "maintenance free" (AKA "impossible to maintain as needed" ) batteries.

Good quality, properly maintained batteries can last a long time. My house bank is now 10 years old and going strong. As often stated, batteries don't die, they are murdered. Mixing chemistries is just another creative way to murder batteries. And "cheap" batteries are false economy.

You do have a good solar regulartor right?

Concur! What you can do now is to use the current battery bank around 65% to 70% daily disharge rate and say goodbye when they run out of juice, maybe one year more or less and then replace them with better and bigger bank.

[monte]

The ER660 batteries are not maintainance free, they have access plugs for checking acid level. I want to add similar batteries. The ER650 dont seem to have the plugs. As far as Im concerned lead acid is fine for now, I can't see a reason to change but glad to hear why anyone would think I should.. We had similar on our last boat and rarely had to add water, The regulator is Victron 85 150 MPPT so it will look after the batteries with regular equalization, although I do prefer to equalize manually so I know what is going on with gassing and high voltage alarms, as well as checking the fluid levels beforehand.

[colemj]

http://automotive.exide.nl/downloads..._2014%20v2.pdf

Are you sure those caps are removable? I mean, have you tried to remove them? Exide certainly markets those batteries as dual-purpose start/house sealed maintenance free.

If they are indeed all of that, then they are not the best choice for a heavy-usage house bank full-time cruising.

Mark

[monte]

yes they are removable, I unscrewed on and looked in to check the fluid level. I guess I should just try match the Ah and A as close as possible with another brand. Thanks for that link Mark, thats the only mention of the ER 660 I have seen anywhere. I cant read Dutch though so not sure what they are saying about it.

[donradcliffe]

Originally Posted by sailinglegend

This is very bad advice - again - from someone who has been in the business for so long!

Any battery can get fully charged at even 13.2 volts, BUT they will not charge properly, and as colemj says they WILL sulphate and die prematurely.

Batteries need to reach their 'gassing voltage' when charging to help burn off the lead sulphate that forms as part of the discharge process. So the proper charging voltage is essential, and that is not always provided by the pre-sets available. Best practice is to have chargers that allow custom settings for absorption and float voltages - and follow the manufacturers recommendations.

_________
Ignorance isn't what you don't know, it's what you think you know that is incorrect.

I mixed gel and FLA batteries for a season when FLA was all I could get in the Solomons. From my experience, charging FLA batteries at gel voltages (14.1v acceptance/13.6v float) will not 'murder' them, especially if you have solar so that the batteries stay over 13v all day.

[monte]

the standard charge algorithm for the victron controller is absorption 14.4 , float 13.8, equalisation 16.2@8% max 1 hr

[belizesailor]

Originally Posted by monte

yes they are removable, I unscrewed on and looked in to check the fluid level. I guess I should just try match the Ah and A as close as possible with another brand. Thanks for that link Mark, thats the only mention of the ER 660 I have seen anywhere. I cant read Dutch though so not sure what they are saying about it.

In that case, maybe stick with similar (absolutely nothing wrong with flooded in general) and see how they hold up.

Part of the reaction here I think is that Excide is known more for cheap batteries.

Try Google Translate on the Dutch.

[hellosailor]

Oh, DUTCH (?!) Exide batteries supplied in Oz....

If I may suggest, find out the correct charging voltages from Exide. Since different battery makers use different chemistries and those may vary a little, confirm that whatever conveniently similar batteries you are buying do have the same--or very similar--voltages. Odds are just about anything will be within 1/10th of a volt and that will still be somewhere between the optimums for both. As we say "good enough for government work".

Since what you have can be maintained--odds are you'll do just fine and six or eight years from now you can worry about what to buy, when that toxic lead is globally banned and obsoleted by lithium batteries. Which probably won't need expensive BMSes or be fire hazards by then, either. (G)