Any downsides to transplanting my 1300000uF capacitor from old SLA bank to new LFP bank?

[Maast]

I can't think of any downsides to transplanting the 130000uF electrolytic capacitor to the new LFP bank other than having to be really careful with precharging.

It was on the old bank to help out the inverter with sudden high loads and a bad inverter induced DC ripple under heavy load. The new bank has much less internal resistance but I'd think it'd help there with both too.

If I were buying new I'd use a supercapacitor, but I don't feel like spending any more money and it wasnt cheap when I bought it either so I definately want to find a use for it.

Thoughts?

 

[FilterGuy]

The new bank has much less internal resistance but I'd think it'd help there with both too.

I am a believer in simplicity.... so before you put it on the new bank, make sure it is needed. If it is not needed then the capacitors will just be another possible point of failure without adding value. There will also be leakage current that is just wasting power. Also....it costs you nothing to not use it. The original purchase cost is a sunk cost whether you use it again or not.

If you do decide to do it and are carfull about (pre-charge and discharge when the system is shut down) then it should be ok.

 

[Maast]

I'm probably going to do it, at the very least it'll help with the inverter ripple and evidently the Chargerys are quite sensitive to ripple, even though I'm going overboard a bit with isolating that with diodes and a 330uh inductor powering it via the external power port. Putting inductors on all the sense leads too. (shrug) I have a bag of 20, might as well use them.

Can't hurt, might help and having a $200 capacitor sitting on a shelf collecting dust pains me in a way I can't easily describe...

 

[toms]

I can’t see any downside. The last few packs i have installed i have used second hand maxwell 165F supercaps in parallel with the LiFePo4.
The surge current for starting pumps and compressors is removed from the LiFePO4, as well as inverter charge ripple.

As stated, ensure capacitor voltage is equalised with battery voltage before connecting. (use a precharge circuit as you would when connecting an inverter).

If you connect the cap in parallel to a bus bar, and fuse it appropriately, it could fail open or short circuit without compromising the rest of your system.