Hi folkes,
Anyone has some input in this?
I have been using a big led acid battery.
The battery is stiil in perfect state.
I am switching soon to lifepo4.
I don’t want to just discard the led acid battery since it is still good and also quite big.
Been looking at paralizing led and lifepo4 but getting mixed signals.
Done some investigating into adding an extra led battery charger and small invertor to maybe connect the led acid to the ups side.
I use ESS and soon dynamic ESS, so cerbo needs to know about the extra battery beyond the lifepo4.
How could i solve this?
Anyone have some smart input?
You add a BMV.
BUT… And its a big one.
The two battery chemistries do not have the dame charge profile. So you may end up having battery problems either aging the lead acid faster or overcharging the lithium. Why i say may as it depends on how clever the lifpo4 is.
Lead acid one needs alonger absorption and temperature compensated charging. It requires more power to float.
Not saying it doesn’t work.
Hi, thanks for the reaction.
I use a victron smartshunt, so a bmv does seems overkill.
I know the two batteries are different, thats why i am not willing to just put them in paralel. Eventhough some people on the onternet say it is no problem.
I have been looking into using a cheap invertor on the led acid pack. Then charge the led acid with a seperate charger (i can connect it after the shunt, and will turn up as an extra DC source in cerbo.)
But then multi/cerbo does not know about the extra capacity wich it is going to need to make the right calculations for dynamic ESS.
I could just add the capacity to the smartshunt i think, but there is another problem. How can i determine to switch on the seperare led acid charger when ESS starts charging the batteries, either by grid or solar.
I am now thinking of just keeping the led acid charged and use it only in energency(long term grid fail and minimal PV) to charge the lifepo4 via a seperate invertor connected to the L1 of the multi. But this seems wastefull to me because grid fail almost never happes here.
So you have the use it or loose it scenario.
You can have a look at the cyrix battery combiner
Then have a has dc system? It means a second shunt though
I use a mixed lead acid LiFeYPo4 environment. In summer only LiFeYPo4 is used in Winter after LiFeYPo4 are discharged the lead acid deliver power until cut of is reached.
Those are my settings. You have to adjust Victron settings for absorbtion etc. to match those.
Please ignore Pb 400 Ah in the picture, this Batterie is broken. All my batteries are second or third life.
Ah yes. And thats the other point the charged voltages need to be the same.