DIY Manual

33 | P a g e 10-543-1 REV A

DIY Manual

Let’s say your Classic is producing 30A into the battery bank, your inverter is consuming 20A, your

ending amps is set to 8A, AND you use the internal shunt. The net difference is 10A (30A – 20A)

going into the bank but on the Main Status page the Classic displays 30A into the bank, so this

may be misleading to you. The 30A shown on the Main Status page needs to decrement to 8A

for the Classic to transition to Float. But this may or may not happen due to the demand

(outgoing 20A) on the system. So, your Classic is making 30A and that current value is not

decreasing at the normal rate, as you expect it to eventually drop to 8A and go to Float.

Now let’s assume you are using an external shunt with the Whiz Bang Jr. On the 4

Status page

you will see the current differential displayed, in this case the 10A differential. When this value

decrements to 8A (ending amp setting), the Classic transitions to Float. Now you have a way to

observe your system in operation and know when it will or should go to Float. Mathematically

the Classic will go to Float at the same time in both scenarios. But with the external shunt and

the Whiz Bang, Jr, now you have a better understanding of the current in and out of your system.

PLANNING YOUR BANK

Rules to keep in mind for a healthy battery bank …

• A battery bank comprised of a single series string charges and discharges better than

a bank of parallel strings.

• Do not add new batteries to a bank of batteries that are more than one year old.

• If you replace batteries, replace all in the same string.

• Use same battery type and size. For example, do not mix flooded lead acid with

AGM; do not use a 100Ah battery with a 250Ah battery.

Series versus Parallel

As mentioned, a single series string is best. Say for example you are new to solar and building

your first system. You start off with a 12V bank because you already own a 12V inverter which is

sitting on the shelf waiting to be used. OK, you can buy a single 12V battery. Or you can buy two

6V batteries and wire in series to effectively make a “single” 12V battery.

12V, 100Ah

12V Bank

Parallel

Figure 4

12V, 100Ah

12V Bank

Series

Figure 5

6V, 370Ah