Hello, I intend to interpose a battery protect between all the chargers and the batteries.
mppt, 230v, alternator.
but i have a doubt.
the battery protect manual says that reverse currents are not allowed.
Well, at night the smartsolar mppt uses about 0.03A from the battery. This small current would flow from the battery to the smartsolar through the battery protect in the opposite direction.
It's possible?
Thank you
Why do you have your Battery Protect in the Charging Circuit? I would not put the Battery Protect in the Charging Circuit. I would connect it between battery bank and the loads. What you trying to "protect" ?
If you really need 30 ma reverse current, you could try adding a Diode 1N4001 + 10 ohm 1/4 watt resistor + 1/4 amp SB fuse all wired in series and then connect that circuit across the Load & Batt terminals of Battery Protect. Orient diode band away from battery. At 30 ma the MPPT will see approx 11.6 volts = 12.6 v batt - 1 volt drop.
it is a solution clearly presented in the manuals of all battery protect.
Specifically it is written that it can be used to protect the battery from a smartsolar or 230v charger.
But there is no diode in the diagram.
This collides when the manual says that 'uncontrolled' reverse currents are not allowed in the battery protect . Maybe 30mA of the smartsolar is not considered a "runaway current"??
I intend to protect the 2 batteries in parallel from a possible internal short circuit of one of the two during unattended charging.
the Battery protect between the chargers and the batteries will be controlled by 2 NC thermal contacts on both batteries. in case one exceeds 55 degrees, the battery protect will disconnect all the chargers.
the battery sense is not sufficient for this because it is on only one of the two batteries and I cannot put 2 of them to control the Ve smart network chargers.
for this I will use the battery protect controlled by the thermal contacts on bo
th batteries.
really no victron technician can tell me if the battery protect Can it be used between chargers and batteries?
including the smartsolar which would absorb 30mA in the opposite direction at night?
Luckily someone had already had my same doubts..
Victron probably likes him more because they answered him.
At night (or when the solar is insufficient) the voltage is higher on the OUT terminal than the IN. Effectively the controller is powered by the battery (while a very small current). Isn't this a problem?
This load is milliamps, easily able to be dissipated and is within the allowable amount of reverse current.
4 In the previous point, if the BP activates (disconnects) when the battery voltage is higher than the MPPT then isn't this a problem?
No, there will not be any meaningful current flow from the battery to the MPPT in this case. The MPPT and solar array is not a load as such.
It is clear that the maximum reverse current allowed in the battery protect should be specified in the manual.
because anyone who has a normal brain and reads "reverse currents are not allowed", thinks that the schemes with the Battery protect on the chargers, proposed by victron, do not make sense.. When instead it is possible to have small reverse currents and it is not specified in the manual .
