DC-DC charger

[Sasquatch]

Apologies in advance if this is a daft question, but electrons aren't really my bailiwick.

My van has a DC-DC charger, and I know that when the van is sat idle the maintenance charger also keeps the leisure battery topped off via the DC-DC thing.

But what about the reverse? When im on the mains hookup and the leisure battery is receiving a charge will the DC-DC unit work to keep the fehicle battery charged? Is suspect not, but we all know what assumptions are the mother of.

 

[StratosFearXX]

Might do. Stick a meter on the SB when you're hooked up.

 

[Sasquatch]

Might do. Stick a meter on the SB when you're hooked up.

Good idea!

 

[ginkster]

Depends on which DC-DC you have. Victron Orion’s don’t charge the SB while on EHU. I understand some Renogy and others do.

What maintenance charger do you have and how is it wired in?

 

[Sasquatch]

Ita a Sterling Power DC DC charger.

The maintenance charger is a CTEC item wired across the starter battery +ve and a ground on the inner wing,

 

[Stay Frosty]

Our Renogy DCC50S has two inputs, one from the starter battery and one from the solar panels.
The starter battery won't charge the leisure battery unless the engine is running and the smart alternator is producing an high enough voltage to do the trick.
I've got a standalone Victron smart charger that works via the EHU but realistically I've used it possibly twice ever.

 

[ginkster]

Ita a Sterling Power DC DC charger.

The maintenance charger is a CTEC item wired across the starter battery +ve and a ground on the inner wing,

I believe many Sterling units do charge the SB while on EHU, but not all. Your manual should say or maybe Google the serial number to check. There are loads of different versions so you would need to check your specific one.

Do you have a mains charger on the LB side? If so, and your Sterling will charge the SB, then there is no need for the maintenance charger. Just plug in EHU and both batteries will get charged.

Or, there is no need for a mains charger on the LB as you could power the maintenance one off your EHU and it will charger the SB which will in turn trigger the DC-DC and charge the LB. Hope that makes sense.

 

[DXX]

If it’s this one it looks like it doesn’t:

Sterling BB1230 'Pro Batt Ultra' Battery-To-Battery Charger - 12V/12V 30A

Sterling BB1230 Pro Batt Ultra multi-stage 12V/12V 30A Battery to Battery charger. Euro 5/6 smart alternator & regen braking compatible.

www.12voltplanet.co.uk

Importantly, once the engine is turned off the charger automatically isolates the starter and leisure batteries from each other to prevent accidental discharge.

 

[Sasquatch]

Aye, it has a sergeant unit on the LB side. While it does charge it's for a very crude charging profile so for SB charging I'd prefer the Ctek for longevity reasons.

I'm just curious as to whether the SB would be charged when on the mains hookup while camping.

Edit. Yes DXX, looks like that one, so that's the question answered. Cheers.

 

[DXX]

If you have solar the LB and SB issues tend to disappear unless you park in a garage.
Well worth the expense IMO.
I have a CTEK and while it has limitations compared with Victron gear it’s very small and so far reliable.

 

[Stay Frosty]

Get solar!

 

[Salty Spuds]

Get solar!

And an AMT 12

 

[Sasquatch]

Get solar!

I've got solar!

 

[DXX]

I've got solar!

Get a CTEK then assuming the PV is within it’s limitations.

 

[Stay Frosty]

I've got solar!

Is it butch, manly solar though, currently banking anywhere between 20 and 200 watts at Busfest... depending on what size cloud they send over the Malverns.

 

[Stay Frosty]

Get a CTEK then assuming the PV is within it’s limitations.

Or a Renogy DCC50S as they're great value, I'm on my second one so they might not be long term but this one is reined back from the 50A they will produce so may well last longer this time.

 

[Sasquatch]

Is it butch, manly solar though, currently banking anywhere between 20 and 200 watts at Busfest... depending on what size cloud they send over the Malverns.

I don't know how many wattsies it makes. Lots of volts though.

 

[doncarlyon]

What's connected to what?

Your EHU provides power to a ctek on the SB?

 

[Stay Frosty]

Perhaps I should ask "does it go up to eleven?"
Volts will be a constant from the panel but the watts will rise and fall depending on whether you've got a clear shot at the sun... basically parked at right angles, roof up and parked on a turntable so you can track the sun.

 

[boxelder]

Lots of volts though

The CTEK can only cope up to 23v (if it works at all on solar - can't get mine to)