Table of Contents

DRAFT - please report errors

DIP switches on Renogy DC-DC chargers

TL;DR

(about these summaries)

profiles without float (lithium chemistries)

Li Boost voltage SW1 SW2 SW3 SW4 SW5
LiFePO4 14.0v OFF OFF ON ON OFF
LiFePO4 14.2v ON OFF ON ON OFF
LiFePO4 14.4v OFF ON ON ON OFF
LiFePO4 14.6v1) ON ON ON ON OFF
12.6v2) OFF OFF OFF OFF OFF
12.8v OFF OFF ON OFF OFF
13.0v OFF OFF OFF ON OFF

An explanation of Floatless charging

profiles with float (lead chemistries)

boost

Pb Boost voltage SW1 SW2 SW3 SW4 SW5
14.1v3) OFF ON ON
14.4v4) ON ON ON
14.7v5) OFF OFF ON

float

Pb Float voltage SW1 SW2 SW3 SW4 SW5
13.2v ON OFF ON
13.5v OFF ON ON
13.8v ON ON ON

using a lead profile to float Li

There are reasons for and against "floating" lithium.

Renogy Li profiles are charge-and-stop:

  1. charge to the selected Boost setpoint
  2. stop charging
  3. drift down to the reBoost setpoint, typically 13.2v,if loads are present
  4. start the charging cycle again

If you want to hold a 13.2v floor instead of cycling repeatedly you might charge use a Pb profile to charge to 14.1v6) and “float” at 13.2v. This would let the bank relax to somewhere between ~60-70%,7) although with light loads you might not fall to 13.2v until sundown.

A 13.8V float is unacceptably high8); it would pin the bank at 100% all day. 13.5v, the last option, may be acceptable if you are running heavier loads. 13.5v will put constant (albeit relatively gentle) charging pressure on the bank. Experiment with it; if it pins SoC at 100% all day then 13.2v might be healthier for the battery.

1)
not recommended - secessus
2)
3S Li-NMC, for example
3)
gel?
4)
AGM?
5)
flooded?
6)
the lowest available
7)
it's notoriously hard to predict, so play with it - secessus
8)
IMO - secessus