Jim's RV build electrics

Solarfun4jim

Solar seduced :-)
Joined
Sep 22, 2019
Messages
746
Location
Sunny Scotland
Rv electrics.jpg

Some of my setup modifications i have made are:
Placed a layer of compressible insulation between the battery cell faces.
Installed 6mm to 10mm aluminium flanged studs on cell terminals. (All connections torqued to 4Nm)
Installed flexible braided busbars across cell terminals and from cell pack to fixture points, thus relieving stress on studs due to movement.
Installed a three point compression fitting applied to a flatplate to distribute compression evenly, rather than application on the outer fixture bars. Belleville washers centred over non threaded bolts(so no thread hang ups or galling).
Created a relay board with SSR's to directly control the remote on/off functionality of victron inverter and SCC(such that i dont need contactors) using a Chargery BMS. Also powers down the BMS in the event of an over discharge event or low temp disconnect. (Uses the BMS two signal assistant on inverter/charger).
Installed a three point disconnect switch with inbuilt precharge circuit for inverter surge protection on initial power up.
Installed a seperate disconnect switch on the negative line, to completely disconnect everything bar the two shunts.
Chargery shunt only used for OCP. Chargery BMS externally powered to maintain most accurate voltage measurements of all cells.
Victron shunt installed to accurately monitor pack capacity.
 

Solarfun4jim

Solar seduced :-)
Joined
Sep 22, 2019
Messages
746
Location
Sunny Scotland
Some paramter settings i'm going with:

Charging...
Inv/charger: Bulk =3.4v(27.20v), Absorb(taper down) 1hour,Float = 3.35(26.80v)
Solar charge controller: Bulk 3.4v, Absorb 10 minutes, Float 3.35v (i never want my cells to be sitting 'full').

Discharging...
Inverter/charger: Cut off 2.95v(restart 3.2v)

BMS settings...
Over charge protection - 3.64v
Over charge current - 105A
Over discharge protection - 2.51v
Over discharge current - 250A
Low Soc cutoff - 0%

Balance function start - 3.4v
Stop diff - 8mV
Balance in charge state only.
 

willo

Solar Addict
Joined
Apr 8, 2020
Messages
388
Very nice. If you don't have one, add a cover over those battery terminals to prevent shorts from falling objects.
I didn't see a precharge circuit, be careful when you turn on the battery cutoff.
 

Terrapin

Solar Enthusiast
Joined
Jan 4, 2021
Messages
315
Location
New England, USA
Bravo, I may get the longer braided buss bars than I have now. I bough the actual needed length but can see the obvious advantage of a pre-bent installation. I noticed quite a bit of resistance when trying to just compress or flex them.. TY
 
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