question

VanMan avatar image

Multiplus Cables Overheating

I have recently installed the following

  • 335 W Solar Panel
  • SmartSolar 100|30 MPPT
  • 200 Ah Smart Lithium
  • SmartShunt 500Amp
  • 12|2000|50 Mult
  • BlueSea 6006 (rated 300amp)
  • Self Made Bus Bar (1x.25 with 3/8 holes -or- 25x6 with 9.5 holes)

I have been testing things before putting the system under (big)load and things have been coming along nicely. Today, I put the system under a 1500w load. As soon as I do the SmartShunt temp begins to rise quickly. All cables are getting warm (Pos and Neg, Battery to Bus and Bus to Multi). The cables are 1/0 AWG. Connections are tight. When the temp gets to 40C or 105F I am removing the load.

I've added pics of system and screen shots from MPPT, Shunt and Multi.

Any help would be appreciated.


VictronPackage.pdf

Multiplus-II
victronpackage.pdf (21.7 MiB)
10 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

2 Answers
Justin Cook - Bay Marine Supply USA avatar image
Justin Cook - Bay Marine Supply USA answered ·

@VanMan, it is not permitted to use the Victron Smart LFP batteries without a BMS; do you have one on the system that isn't shown? These are NOT "drop-in" batteries and a BMS is absolutely required as noted in Section 3.1 of the user manual.

I don't believe that's what's causing your cables to overheat, but it's a critical error that must be immediately corrected to prevent irreparable damage (not covered by warranty, I will add) to your components.

I do believe that what's causing your cabling to overheat is that it's undersized; as specified in Section 4.2 "Connection of Battery Cables" in the MultiPlus Compact user manual, 2/0 (70mm2) is the required cable gauge for connection of the MultiPlus Compact 12/2kVA to the battery bank. Undersized cabling causes increased resistance, which causes heat, which causes more resistance, which causes more heat, etc. etc.

Please thoroughly read, understand, and follow the requirements laid out in your user manuals, including the purchase and installation of a Victron BMS for your system, charge disconnects, load disconnects, and all other required components, as what you show here, as it stands, will fail sooner or later, possibly catastrophically, and will not be covered by warranty because the failure will be due to installation error.

If you are at all uncertain about the remaining components required to make your system safe, functional, and properly operational, please consult a reputable, experienced, Victron-trained systems installer to assist you in correcting your system, or reach out to an authorized Victron dealer or distributor for further assistance.

Share
10 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Trip-Tracks avatar image
Trip-Tracks answered ·

Minimum 2/0 cable for the 12/2000 Multi, 3/0 even better.


Also, fuse to inverter are not going to last at 200A. 300A would suit better, but you need the larger cable for the larger fuses.

Share
10 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.