To you Victron experts - charging the van battery.

[kipperman]

So my new set up in the van - Fogstar drift pro Li-Ion battery, Victron Smart DC-DC charger for charging leisure battery from van (smart alternator), Victron Smartsolar charger and Victron Multiplus 2000W inverter. This works all very well -

But unlike my old Bilbos sergeant unit, there is no way of charging the van battery. We spend a lot of time in one place, and there is a reasonable amount of load on the van battery ( dashboard lights up etc when you lock/unlock). So this seems a bit like an oversight.

The only solution I can think of at the moment is to fit another DC-DC charger but essentially in the opposite direction and make sure that the other charger is switched off when the van is stationary. - that is to use the leisure battery to keep the van battery topped up. No likely issues with discharging the leisure battery as it is verily massive. I don't particularly like this idea as I wonder what the effect might be if both chargers were switched on at the same time. Reading through the Multiplus guff, I note that there is a 1A supply that appears to be for charging the van battery, but 1A I suspect is probably p£$*ing in the wind as regards charging unless the van battery is full.

What is the ideal solution?

 

[ginkster]

Ablemail AMT12-2. About £65, tiny, simple to fit and works great.

 

[Dellmassive]

the multiplus will trickle charge 1A when on EHU.

but as you say thats a bit feeble.


i went for the AMT12-2

Thread '[Guide] Battery Maintainer (for Starter battery) -- How I Done It --'

25 Nov 2020

[Guide] Battery Maintainer (for Starter battery) -- How I Done It --

Right so its that time of year again . . . . . . . . Winter & (Lockdown 2020)




The van might be layed up not being used, which will lead to a flat battery in around 3 weeks.

The cold weather doesn't help the battery's either.






This Thread is about using "what you have" to "back charge" the starter battery...

lets look at some options. . . . . . . .

1# Connect a 240v/EHU charger to the starter battery and leave it connected, that's fine if you have a drive way etc, have a look for the...

• Dellmassive
• battery drain dellmassive how to guide vehicle battery
• Replies: 108
• Forum: Electrics, Lighting, ICE, Security

• 

+


there is a PRO version now that has integrated BT - BTLOI


and a new 5A high power version with BT


.

 

[kipperman]

Thanks all - Can I assume therefore my plan is feasible - i.e the ablemail "back to back" to the DC-DC leisure battery charger. I just have this concern that the leisure battery will be trying to charge the van battery, and vice versa. The DC-DC charger that charges the leisure battery is switched off when the engine is off, but what happens when the engine is switched on and the two are in competition?

Just don't want to blow anything up..

 

[Dellmassive]

Thanks all - Can I assume therefore my plan is feasible - i.e the ablemail "back to back" to the DC-DC leisure battery charger. I just have this concern that the leisure battery will be trying to charge the van battery, and vice versa. The DC-DC charger that charges the leisure battery is switched off when the engine is off, but what happens when the engine is switched on and the two are in competition?

Just don't want to blow anything up..

nothing,

the ablemail sees the starter is charged by the engine and switches off.

 

[kipperman]

Awesome - that makes sense. Cheers @Dellmassive

 

[TonyM]

Reading through the Multiplus guff, I note that there is a 1A supply that appears to be for charging the van battery, but 1A I suspect is probably p£$*ing in the wind as regards charging unless the van battery is full.

Have a look to check the conditions under which the 1A is supplied. 24Ah every day should be enough if it's a permanent supply. Remember that you are not trying to charge a battery, just to hold it at its current level of charge to compensate for those door openings etc.

Failing the Multiplus, the simple easy fit, fit & forget option is to use a Battery Master. Fit it anywhere you have the starter & leisure battery live feeds close together - either side of the DC-DC charger would be an obvious place.

The Battery Master supplies a constant 1.1A if the starter battery is accepting charge & the leisure battery is 0.75V higher than the current starter battery voltage (which should be always with a lithium leisure battery).

If the leisure battery is 0.75V higher than the starter battery voltage (which should be always with a lithium leisure battery) and the starter battery is accepting charge, the Battery Master supplies a constant 1.1A.

Available for £69.95 from Wattguard, which is run by the son of Eddie Jones, the guy who invented it.

EDIT: A quick look at the Multiplus manual suggests that it might supply 4A, rather than 1A. But it only operates under certain conditions.

The 12V and 24V MultiPlus is equipped with a second charge output intended for maintenance charging of a starter battery. It
uses a simple circuit with a current limiter and diode, allowing a continuous trickle charge (4A) from the main (domestic) battery
to the starter battery. Due to the diode's 0.3 - 0.6 V drop, charging only occurs when the main battery is being actively charged or
when the starter battery’s voltage is much lower.

 

[kipperman]

thanks @TonyM - I shall do a bit of research later.