question

jordaanp avatar image
jordaanp asked

deep cycle 220ah gel batteries cycle of charge

Hello community.

I have a question that has probably been answered before but I cant seem to find an answer.


I have three 220AH deep cycle gel batteries (brand new) installed on my boat. The connection is in parallel.

We also installed a solar array of 730W (series connection of two panels) connected to a 150/70 MPPT. We connected the MPPT directly to the battery bank as we do not have space on the bus bar.


My question is what is the voltage on the batteries when they are 80% discharged. and 50% discharged.

I am very confused as to the voltage of the cycles and want to make sure we are doing it right.

Many thanks

Pieter

Cyrix Battery Combiner
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1 Answer
Ulrich avatar image
Ulrich answered ·

Hello Pieter,

It is important for serial installation that the batteries are all connected to a busbar with the same cable length so that the cable losses and thus the voltages are the same for each battery.

The same applies to the solar charge controller. So that each battery receives the same charge, the cable length to each battery must be the same. Otherwise the voltages are different and thus the charge current flows.

I would definitely use a SmartShunt. This can be set exactly to the type of battery and it shows you the state of charge of the batteries. A BMC 700/712 might be better on a boat because it has its own display and you don't need a Bluetooth device.

The SmartShunt not only measures the voltage to display the charge status, but also the outgoing and incoming currents. Thus it is more accurate than the pure voltage method to measure the state of charge.

Victron Energy has a ton of videos on the subject. Just have a look at their YouTube channel. (https://www.youtube.com/channel/UCMWYxDjwpyQGw6zg5p9SNhw)

I hope I understood your question and gave you some useful pointers. If you have any questions, please ask.

greetings

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