westen avatar image
westen asked

why can I not use a smart battery protect between battery and inverter?

Hi all,

Just bought a battery protect (the larger smart one/forgot the details, sorry).

Thought I could hook it up between battery and loads and have it turn off current in case of battery-low-voltage. As a safety measure thing.

Then I`read:

you cannot use this device between your batteries and an inverter (...)

Is this for real?

Of course I have an inverter! Don't we all?

How am I going to battery (lowvoltage) protect my system?

My set-up is 4x 160W panels, MPPT 100/20, 12V system

thanks for any advice,


Battery Protect
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3 Answers
Justin Cook avatar image
Justin Cook answered ·

Hi @westen, welcome to the Community!

You are correct, you may not use the BatteryProtect between a battery and an inverter. All Victron inverters have built-in adjustable low-voltage disconnects, so they don't need any external devices to accomplish that functionality; 3rd-party inverters, well... the programmability of the inverter depends on the manufacturer, and that's a conversation best had with them.

Using a BatteryProtect to directly disconnect the main DC line of an inverter will, sooner or later, destroy the BatteryProtect, and since it's an expressly forbidden configuration, it will not be covered by warranty.

Please see the user manual here for details on acceptable connection methods.

There is a wide range of other manufacturers' latching relays that may be used to accomplish what you're trying to do, if your inverter does not have such basic functionality as an adjustable low-voltage shutdown, but, unfortunately, the Victron BatteryProtect is not one of the products that could work for you.

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aceclement avatar image aceclement commented ·
I followed the instructions about wiring a relay to control the inverter on off remote between the BP, it didn't work. Can someone please be specific and detailed on the wiring so I can determine if I did it wrong or if I just need to return my battery protect for a refund. I find it to be a useless device for my needs if I can't use it with an inverter.
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gallaxial avatar image
gallaxial answered ·

IF the inverter do not have : adjustable low-voltage shutdown

you can use this device ?

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shaneyake avatar image shaneyake commented ·
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northwestnick avatar image
northwestnick answered ·

@Justin Cook - Bay Marine Supply USA
Hi Justin! After I cooked my Smart Battery Protect 48/100 by connecting it to an inverter, I found your posts all over the internet warning not to do so. I very much appreciate your efforts to spread the word. But, with all due respect, the user manual (which I had read) does not "expressly forbid" direct connection to an inverter. I wish it did. Here's what it actually says:

"4. The short circuit protection of the BP will be activated if you try to directly connect loads with capacitors on their input (eg inverters). For that use case, please use the BP to control the remote on/off switch on the inverter, instead of disconnecting the higher power DC line."

That doesn't sound like an expressly forbidden configuration to me. All it says is that the configuration won't work. No mention whatsoever that the BP will be destroyed instantly the very first time you connect it to a non-Victron inverter.

Contrast this with the clear warning in the previous section (3) stating that reverse currents are "strictly forbidden" and "will damage the device". Now, THAT is the kind of language they need to put in the Inverter section.

Inverters are mentioned one other time, in the Error/Warning Codes section.

"E1: Short circuit
Short circuit protection is activated in the event of a short circuit, an overload condition or excessive inrush current - such as when attempting to directly power an inverter
1- Check for a potential short circuit condition
2- Confirm that the load current draw does not exceed the BP current rating
3- Use the BP to control the remote on/off switch on loads with high inrush currents, rather than directly powering/disconnecting the DC supply
4- Check for loose/high resistance connections and ensure that appropriate gauge wiring is used in the installation"

Doesn't that sound like a nice troubleshooting sequence to follow after you've connected your Battery Protect to an inverter and found that it wasn't working properly? Again, no mention that you should NEVER EVER do this because it instantly destroys the device. And... for the record... there is no E1 error when this happens. The BP just quietly toasts itself, and you won't even know that it's happened until you happen to test it... or until you actually need it to do its job, in which case your battery just runs dead instead of disconnecting.

I'm not bitter. I just wish I had found your posts sooner. Like you, I hope that the message reaches people who need to see it. I fear that there are many more of these units out in the field which are similarly damaged, but their owners won't know it until it's too late and their batteries run dead.

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