Battery Connection Questions : Linx Distributor, Shut Off Switch, Pre-Charge Resistor

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stevew asked Jun 24, '23

Battery Connection Questions : Linx Distributor, Shut Off Switch, Pre-Charge Resistor

Greetings from Southern California and Thank You for the information shared here.

My relatively simple installation includes two 160AH Victron batteries. I’m looking for opinions on their parallel cabling and connecting.

Simple / traditional cabling at the battery posts with positive from one battery and negative from the other ?? With equal length cables.

Bus bar connection via a Linx Distributor ?? And if via a Linx - connections at the main bus bar connectors or at the fused connection points ?? I’ve seen both in several installation diagrams…

In all of my previous similar work - it’s always been recommended to have the battery shutoff switch on the negative side of a battery. I’ve noticed that Victron installations seem to prefer this switch on the positive side…. Can anyone explain why ??

And… this shutoff switch on the positive side ought to have a pre-charge circuit incorporated - correct ??

All answers and comments are sincerely appreciated

Thanks again,

SW

Lithium Battery

2 |3000

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Answer 1 · 2023-06-24T09:27:36Z

seb71 answered · Jun 24, 2023 at 09:27 AM

Is this a 12V system? Stationary (house) or mobile (such as an RV/boat)?

Do you have any parts already? If not, consider a 24V or even better, a 48V system.

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For sure it is much better to use bus bars. You can DIY from copper bars.

Each battery should be connected to the busbars, using equal length wires for positive and equal length wires for negative connection. Positive and negative wires can be different lengths.

Use a fuse on each positive wire between each battery and the positive busbar. As close as possible to the battery.

In Europe you can use NH type fuses and for NH fuses there are fuse holders which can also act as disconnectors (for emergency disconnect). Not sure if these are available in USA.

You can manually precharge the inverter capacitors. Should be fine, unless you plan to frequently disconnect the batteries for some reason.

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2 |3000

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stevew commented · Jun 24, 2023 at 02:10 PM

Thank you Seb71 !

It’s a 12V system and I already have plenty of the parts. I don’t have a Linx Distributor yet,

(2) 160AH Victron batteries, Multiplus 12/3000, Cerbo GX, Touch50. An MPPT controller and an Orion DC/DC charger too. VE BMS.

I took a chance and purchased everything from a guy who purchased an entire lot of Victron gear (at auction) from a defunct van conversion company. I purchased the Multiplus from a guy that upgraded to 24V. Fortunately - everything works perfectly.

It’s all going into a small vintage RV. Simple objective - to be able to boondock longer without generator usage. 12V to lights (LED), stereo, water pump, furnace fan, compressor driven refrigerator. My BMV700 tells me that I consume about 80 amp hours in a 24 hour period. Most of that is the refrigerator. 120V to TV, microwave, and coffee machine. Propane to the furnace and water heater.

Yea… it’s probably overkill - but plenty of fun.

SW

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seb71 stevew commented · Jun 24, 2023 at 03:48 PM

For an RV you are also restricted by available space. What I wrote in my previous replay was more focused on a house install.

Lynx Distributors are quite compact, but also relatively expensive. And if you need more than one, the cost quickly adds up.

But you do need some sort of busbars. Do not try to connect all those devices directly to the battery posts.

Any positive wire connected to the busbar should be fused (with a fuse properly sized for that wire/current).

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You want the battery-busbar wires and busbar-inverter wires properly sized (cross section/gauge) for the amperage and as short as possible (to reduce losses and cost). 3000W on a 12 V system is quite a lot.

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