Ideal Diode for connecting multiple battery's in parallel

Safely connecting battery packs in parallel requires protection for each battery to prevent higher voltage battery’s from discharging into lower voltage battery’s. The voltage difference between battery packs does not need to be great in order to cause damage. Just a few hundred millivolts can cause current flow into a battery that exceeds specifications and damages the battery.

I developed this Ideal Diode Controller that uses the very robust chassis mount MOSFET (IXTN660N04T4) to protect each battery. One Ideal Diode is used to protect each battery in the system. As many battery’s as desired can be connected in parallel and these devices will isolate the lower voltage battery’s from the system voltage until the system voltage drops to meet the battery voltage. Once equalized the battery’s will combine and share the system load.

These Ideal Diodes can handle 40 VDC max, and have been tested to 60 Amps continuous with no additional heat sink needed, however some form of heat sink is recommended for best performance and safety. Depending on the size of heat sink used these Ideal Diodes can safely carry well over 100 Amps each. Forward voltage drop across the MOSFET is only ~ 0.75 mV/Amp.

These can be a good option for the multi-battery BlueBoat configurations.

Find out more at:

Multiple cable options available.

Next to the Basic ESC for size reference.

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I think it is a very good idea, congratulations, I have been checking your website where you have another product (in development) that can connect two batteries and incorporates a charge switch to disconnect the battery, I am looking for a similar system but I have isolated batteries in each hermetic enclosure and I monitor the battery voltage by reading the cells with Arduino using voltage dividers and voltage reference (1.1V) for maximum precision, well in summary, my question is; Does the individual ideal diode also incorporate a charge switch to disconnect the battery?

I asked this because it would be a better option, much more compact than the typical SSR with standard measurements like this " SSR Crydom", I know that the Thornware SSR also exists but they do not ship outside the US and Canada and they are not as compact because They have to go above the battery in the enclosure and not in the final gap that is left over when you put the battery in the 240 mm 3" enclosure as I think it could with your model.

Thank you

The individual ideal diode (ID-227-01) does not have a load switch to disconnect the battery from the system. The Ideal Diode only blocks current in the reverse direction (from the system into the battery). When the Ideal Diode is Off or On current can always flow from the battery to the system.

The other item on the site (IDLS-227) is a single ideal diode and a load switch combined in the same package, so you would still need one of those for each battery in your system. That part will act as a switch to completely disconnect the battery from the system (bi-directionally) and also has the ideal diode built in for multi-battery protection.

I do not currently offer a part that is a simple bi-directional load switch.

The Thornwave load switches are nice, I have a few of them. But they are larger than they need to be and can be difficult to fit in an enclosure.

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So if I added the ideal diode to my circuit, if I had three batteries connected in parallel, if one of them or two batteries at the same time failed, the third battery that had the correct voltage would continue to supply energy to my components without any type of problem?

Because if that’s the case, I wouldn’t worry about monitoring the voltages of all the batteries and switching between them…

Thank you!

Yes that is correct. If each battery in the system is protected by an ideal diode then only the battery(s) with the highest voltage will supply the systems load. If one or more battery’s have lower voltage for any reason, they will be isolated (protected) from the higher system voltage.

Ideal Diodes behave in the the same manner as a standard passive diode, but with the advantage of much lower voltage drop, power consumption, and heat generation.

This drawing should help visualize it: