4.2 Charge voltage
- Recommended charge voltage: 14V-14,4V per battery (14,2V recommended),
- Absorption time: 2 hrs for a 100% charge, or a few minutes for a 98% charge.
- Maximum charge voltage: 14,4V resp
- Recommended storage/float voltage: 13,5V
- Batteries must be regularly (at least once every month) charged to 14V (max. 14,4V) in order to fully balance the cells.
There is quite a difference between the two. So by applying the Victron recommendations to the Balmar program this is what I came up with:
- Start delay is the same
- High Voltage limit: I would make it 14.2 (even though 14.4 is allowed why push the limit if 14.2 is recommended)
- Compensation limit: 14.2 (There should be no temperature compensation, see last line above)
- Bulk voltage 14.2
- Absorption voltage 14.2
- Absorption time * see note below but keep as is for now
- Float voltage 13.5
- Max Bat temp leave as is
- Max alt temp leave as is
- Batt temp compensation leave as is (zero)
*You can only define the minimum absorption time, not the
max absorption time. You may have to tweak this a bit. The purpose
of the absorption time is to equalize the cells. You just have to do that
from time to time, so if you go to a dock the MultiPlus does it for you and you
don’t necessarily have to do it on the water. If you never go to the dock
you might have to monitor it a few times to see what happens when you leave it set
to 18 minutes
If you have batteries (such as the Victron Smart Lithium) that have an external BMS then you can have the BMS control the regulator and stop charging when any cell in the battery gets to full. This is done using the Victron SolidSwitch as an ON-OFF switch for the regulator.
2 Comments
Ed
I’ve read that lithium batteries should not have any float time. So having the mc614 - shouldn’t we change the minimum float time To 0 and the maximum float time to 0 as well ?
Peter Kennedy
Andre
Thanks for the valuable information. With the new Smart BMS we now have two different battery chemistry interconnected on the same alternator (suppose its a Balmar). Suppose the start batteries are Victron AGM. Does your recommandation for charging profile would change in this context ? How to make sure the Lithium are charged and the AGM not overcharged ?
Peter Kennedy
Since Lithium and AGM are quite different it is more normal to use a Battery to Battery charger to charge one bank from the other. That way each bank gets the charge it needs.
If you try to charge them both from the same source at the same time the lithium battery tends to decide the outcome. Its voltage doesn't vary much throughout the charge cycle and only rises significantly at the end. That would cause the AGM battery to be undercharged for most of its charge cycle.
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