Battery to Battery charger

[Al n Val]

i've trawled the threads and could not find a specific answer to my question

I have a 2018 Autotrail Comanche which has the Sargent EC700 charger controller built in, this as you'll know controls more or less everything in the moho so my question is

Has anyone fitted a B to B charger such as a Victron found here and did you have any hassle with the other equipment inside the moho, such as the step, fridge and anything else. If so how did you get around it.?

For clarity i've asked Sargent and was told that i'd have to disconnect the Sargent split charge relay, mess about with the step and fridge wiring and maybe some other things, the telephone conversation was on a bad line and I couldn't really hear what was being said clearly enough and their was a lot said during the conversation if i'm honest

So over to you guys, or am i wasting my time

Al

 

[Googlebot]

What’s the rating of the relay inside the Sargent unit?

On the EBL on mine it was really simple. Others may know more if the Sargent unit would be the same.

 

[Al n Val]

I think its rated at 20A or thats what i think i heard Sargent say, from the little i know about the Victron unit it could give me 50A plus whilst running the engine.

What does yours produce?

 

[Lenny HB]

I think its rated at 20A or thats what i think i heard Sargent say, from the little i know about the Victron unit it could give me 50A plus whilst running the engine.

What does yours produce?

The split charge relay in an Elektroblock is rated at 70 amps that's why you can run the B2B through the Elektroblock, I wouldn't recommend it with other units.

 

[Googlebot]

I think its rated at 20A or thats what i think i heard Sargent say, from the little i know about the Victron unit it could give me 50A plus whilst running the engine.

What does yours produce?

Mine is a 30 amp model.

Hymer relays are rated at 50amp so you can do this. At least I think they are, Lenny knows much more about this stuff than I do.

Sorry I can’t help more.

^{_{Subscribers  do not see these advertisements}}

 

[Al n Val]

The split charge relay in an Elektroblock is rated at 70 amps that's why you can run the B2B through the Elektroblock, I wouldn't recommend it with other units.

yeah i think thats what they were trying to tell me Lennie tbh, I think i heard them say that i'd have to disconnect it from the Sargent unit itself but that upsets other things like the fridge and step

 

[TinaLes]

Watched a vlog video from Gadget John recently who has an electrobloc with a 20Amp battery charger.
He has now installed the same victron Orion Tr Smart 30amp B2B as shown by the OP, without altering any wiring change from the split charge relay.
He has twin 100amp Lithiums which can take a heavy charge initially ie: 50 amps.
He demonstrates via his victron battery monitor, that his batteries could accept a charge/top up as he uses about 90 amp hours per day off grid.
when he turns the engine on, his leisure batts get an initial 20 amps from the electrobloc before the 30 second delay start of the Victron B2B which then kicks in and delivers its full 30amp charge in addition to the electrobloc, therefore giving him 50amps to the leisure batt bank, which the lithium's can take.
I am not sure the same could be said for using wet lead acid batts though, I would want to disable the electrobloc charger from charging the leisure batts when driving in case there is a conflict in charging state of charge ie: absorption, bulk, & float.
He is adamant that this is not necessary with his Lithium's though and his system is working well delivering 50amps between the two chargers with no conflict.
What do you guys think, I know it wouldn't work with a Stirling B2B, maybe the Victron is different?
LES
Heres the video link from Gadget John as discussed.

 

[Al n Val]

Watched a vlog video from Gadget John recently who has an electrobloc with a 20Amp battery charger.
He has now installed the same victron Orion Tr Smart 30amp B2B as shown by the OP, without altering any wiring change from the split charge relay.
He has twin 100amp Lithiums which can take a heavy charge initially ie: 50 amps.
He demonstrates via his victron battery monitor, that his batteries could accept a charge/top up as he uses about 90 amp hours per day off grid.
when he turns the engine on, his leisure batts get an initial 20 amps from the electrobloc before the 30 second delay start of the Victron B2B which then kicks in and delivers its full 30amp charge in addition to the electrobloc, therefore giving him 50amps to the leisure batt bank, which the lithium's can take.
I am not sure the same could be said for using wet lead acid batts though, I would want to disable the electrobloc charger from charging the leisure batts when driving in case there is a conflict in charging state of charge ie: absorption, bulk, & float.
He is adamant that this is not necessary with his Lithium's though and his system is working well delivering 50amps between the two chargers with no conflict.
What do you guys think, I know it wouldn't work with a Stirling B2B, maybe the Victron is different?
LES
Heres the video link from Gadget John as discussed.

it was that video that raised my spirits tbh and I did ask John if it was possible to fit it to my Comanche and was told a definite yes, i've scrolled through the comments twice to re-read it and it seems to have disappeared

 

[Lenny HB]

He demonstrates via his victron battery monitor, that his batteries could accept a charge/top up as he uses about 90 amp hours per day off grid.
when he turns the engine on, his leisure batts get an initial 20 amps from the electrobloc before the 30 second delay start of the Victron B2B which then kicks in and delivers its full 30amp charge in addition to the electrobloc, therefore giving him 50amps to the leisure batt bank, which the lithium's can take.

Sounds like he has wired it in parallel to the EBL rather than through it.
He gets most things wrong so no change there.

Only watch his videos if you want to know how not to do something.

 

[Googlebot]

Sounds like he has wired it in parallel to the EBL rather than through it.
He gets most things wrong so no change there.

Only watch his videos if you want to know how not to do something.

Parallel is a bad idea, the B2B charger will have certain voltages and parameters to suit, particularly on lithium where low temperature charging will kill the battery so has low temperature protection.

If you want 50 amps, get a 50 amp B2B. Anything else is a bodge.

^{_{Subscribers  do not see these advertisements}}

 

[TinaLes]

I agree chaps, at first I thought how can you have two separate chargers trying to do the same job, both being fed from the alternator, might even be chucking out different charge regimes working against each other.
Very surprised he didnt isolate the D+ to allow the electrobloc to only charge batteries when on hook up 240V

I think he is also relying on the fact that as he is fulltiming in the van, with heating on so the Lithium's will not go less than 6%C, so he doesn't have to worry about low temp charging.
LES

 

[Kannon Fodda]

Effectively when Vanbitz installed lithium with a Sterling B2B to my 2019 Autotrail PVC last year, with even more basic Sargent EC176 PSU/Charger thing, I believe all they had to do to disable the Sargent inbuilt 12V charger was to pull a fuse from the floor behind the driver's seat to disable the Sargent 12V relay. New heavier cables run from the the motor battery to the B2B to suit the 60A potential currents, and then to the leisure battery.

Everything seems to work as before. Fridge runs off the leisure battery and won't operate if the motor is running so there is still some signalling getting through to turn hab 12V off when engine is running (the control panel also goes off). The step I think looking at wiring diagrams is fed from the motor, not the leisure battery. Sargent PSU still charges the leisure battery when on EHU (yes we won't look too hard at the pants Sargent 230V flatline charger incapability.

You should be able to get a wiring diagram from Autotrail. It was at the back of many owner's handbooks, online buried on the Autotrail site. Sometimes Sargent themselves also have wiring diagrams and certainly the detailed manual for their charger units.

 

[autorouter]

He has now installed the same victron Orion Tr Smart 30amp B2B as shown by the OP, without altering any wiring change from the split charge relay.

He says (at 3:00) that the MH has an Electroblock with a mains charger and B2B. That means it doesn't have a split charge relay. If he's right about that, then the two B2Bs can work together - there are diodes to prevent any unwanted backfeed to the starter battery.

If it's in a MH with a split charge relay, the relay will short out the input and output of the B2B, so the B2B will do nothing. That's why you have to find a way to disable the split charge relay.

 

[donkey]

Everything seems to work as before. Fridge runs off the leisure battery and won't operate if the motor is running

Hi Kannon Fodda

Not sure what you mean by that?
The fridge 'should' work on 12v when engine is running.
Geoff

 

[Pausim]

Hopefully the one thing all Funsters can agree on is that Gadget John should always be ignored. His videos should carry a warning “This Man Does Not Understand Electricity”.

^{_{Subscribers  do not see these advertisements}}

 

[AgeingAndrew]

Parallel is a bad idea, the B2B charger will have certain voltages and parameters to suit, particularly on lithium where low temperature charging will kill the battery so has low temperature protection.

If you want 50 amps, get a 50 amp B2B. Anything else is a bodge.

If parallel is a bad idea for the reasons you state, then how does charging with solar work?. While the engine is running the batteries are charged from the alternator/B2B AND solar, with chargers connected in parallel. When on EHU the batteries are charged from mains charger AND solar with chargers connected in parallel. Are you telling us that this does not work?.

If you read the product details from (eg) Victron, Ablemail and other decent manufacturers they state that their chargers can be connected in parallel. In fact, Victron clearly state that ‘unlimited multiple units can be connected in parallel to increase output power’.

If all of the chargers used have a charging profile suitable for lithium and the batteries have a suitable BMS then what is the problem?

Andrew

 

[Diabalo]

I was told by Sargents that the onboard split charge system would need to be isolated when the engine is running or everything will get it's knickers in a twist. The simple way to do this was fit a normally closed relay on the inboard side so the panel still charges the vehicle batt when on EHU.

 

[Jake vE]

Just to throw in what I've done with mine. I have an older EBL which won't take the amps required to run the B2B to the lithium batteries. Like mentioned above, I have pulled the fuse from the starter battery to the EBL and run a heavier cable from the starter battery to the B2B. I have also added a cable from my solar controller back to the starter battery as a trickle charge.

Everything else still runs through the EBL and functions as it should including fridge and step etc but the wiring may be different to your set up as Kannon Fodda mentions. I switched the mains charger in the EBL to the gel setting which will provide charge to the battery when on hook up.

 

[Googlebot]

If parallel is a bad idea for the reasons you state, then how does charging with solar work?. While the engine is running the batteries are charged from the alternator/B2B AND solar, with chargers connected in parallel. When on EHU the batteries are charged from mains charger AND solar with chargers connected in parallel. Are you telling us that this does not work?.

If you read the product details from (eg) Victron, Ablemail and other decent manufacturers they state that their chargers can be connected in parallel. In fact, Victron clearly state that ‘unlimited multiple units can be connected in parallel to increase output power’.

If all of the chargers used have a charging profile suitable for lithium and the batteries have a suitable BMS then what is the problem?

Andrew

Parallel is fine if the charging units are the same. The output of a B2B and an alternator are different, what you end up with is a mash of voltage that does not suit anything.

Solar works on the correct profile as well, or it should if you have a decent controller so can be used in parallel.

 

[Pausim]

If parallel is a bad idea for the reasons you state, then how does charging with solar work?. While the engine is running the batteries are charged from the alternator/B2B AND solar, with chargers connected in parallel. When on EHU the batteries are charged from mains charger AND solar with chargers connected in parallel. Are you telling us that this does not work?.

If you read the product details from (eg) Victron, Ablemail and other decent manufacturers they state that their chargers can be connected in parallel. In fact, Victron clearly state that ‘unlimited multiple units can be connected in parallel to increase output power’.

If all of the chargers used have a charging profile suitable for lithium and the batteries have a suitable BMS then what is the problem?

Andrew

B2Bs are different to Solar and ehu chargers because they are separate sources and prevent back flow. The one with the highest voltage works hardest. The problem with a B2B working alongside the original alternator circuit is you create a loop where the B2B is not only feeding the leisure battery but going back up the older circuit to feed the engine battery and itself, which makes a nonsense of the whole installation.

Some of the more sophisticated units are designed to work in parallel with other identical units that can synchronise their activities.

^{_{Subscribers  do not see these advertisements}}

 

[autorouter]

B2Bs are different to Solar and ehu chargers because they are separate sources and prevent back flow. The one with the highest voltage works hardest. The problem with a B2B working alongside the original alternator circuit is you create a loop where the B2B is not only feeding the leisure battery but going back up the older circuit to feed the engine battery and itself, which makes a nonsense of the whole installation.

Feedback loops are a common feature of electronic circuits, and their analysis is well understood. Whole books have been written about them. You can't design a decent amplifier without accounting for feedback loops.

In this case, the split charge relay and the B2B are connected in parallel. The feedback path is an extremely low resistance - the split charge relay and wiring - so the voltage drop across it will be practically zero. The output of the B2B will be at the same voltage as the input. In other words, the B2B will do practically nothing.

 

[AgeingAndrew]

B2Bs are different to Solar and ehu chargers because they are separate sources and prevent back flow. The one with the highest voltage works hardest. The problem with a B2B working alongside the original alternator circuit is you create a loop where the B2B is not only feeding the leisure battery but going back up the older circuit to feed the engine battery and itself, which makes a nonsense of the whole installation.

Some of the more sophisticated units are designed to work in parallel with other identical units that can synchronise their activities.

No one has suggested a B2B working alongside an alternator feed. In Gadget John's video he is specific - he has a B2B integrated in his EBL, his new B2B charger will operate in parallel to the existing B2B charger. Modern 3+ stage chargers, whether they be solar, B2B, mains or generators should be capable of running in parallel.

The OP (Al) will have to make wiring modifications in order to enable the correct operation of his existing system when fitting a B2B charger but it looks like no-one on here can help him. When I fitted my B2B I used Schaudt's schematics to understand how the system operated, but I think fitting a B2B in a van fitted with an EBL is very easy compared to fitting with a Sargent unit.

 

[Tombola]

Im a bit lost chaps/chappesses
could someone explain simple to me.

whats the issue with the op installing the b2b direct from the cab battery then direct into his leisure batteres after disonnecting the relay/fuse behind the driver seat.

Is it because the same relay runs his step/fridge so they would stop working.

The op doesnt have an existing b2b does he (or have I missed it) only a ehu charger... in which case there wont be a huge loop back will there ?

 

[Pausim]

In this case, the split charge relay and the B2B are connected in parallel. The feedback path is an extremely low resistance - the split charge relay and wiring - so the voltage drop across it will be practically zero. The output of the B2B will be at the same voltage as the input. In other words, the B2B will do practically nothing.

I think that is what I said, I just used different words. Anyway we agree that the B2B is not going to work properly.

No one has suggested a B2B working alongside an alternator feed. In Gadget John's video he is specific - he has a B2B integrated in his EBL, his new B2B charger will operate in parallel to the existing B2B charger. Modern 3+ stage chargers, whether they be solar, B2B, mains or generators should be capable of running in parallel.

I was not referring to Gadget John’s video (he is the last person I would look to for advice). The op raised his question in relation to a Sargent unit with a relay and I thought that was what we were discussing.

 

[Kannon Fodda]

Everything seems to work as before. Fridge runs off the leisure battery and won't operate if the motor is running

Hi Kannon Fodda

Not sure what you mean by that?
The fridge 'should' work on 12v when engine is running.
Geoff

In UK based vehicles built to NCC standards, when the engine is running the habitation 12V electrics are isolated. Slight miswording, that the fridge is the only thing left able to run on the 12V power when engine is on. All other habitation 12V get's disabled by some signalling wire.

^{_{Subscribers  do not see these advertisements}}

 

[Al n Val]

Well I’ve only gone and ordered a Victron isolated 12-12-30 dc to dc charger after speaking to a chap with the same vehicle as me and using the same Sargent charger.

He‘s made no modifications to the wiring whatsoever and it’s all working as it should so fingers crossed it’s all doesn’t go up in flames

Watch this space

 

[Trout bum]

Hi I've just ordered one as well and all the cables and accessories to do the install perfect time to do it when we are locked down ,and will make a difference power wise , after its in stalled I'm thinking next to get an inverter that will sort out power requirements off grid , good luck on your install.

 

[Al n Val]

i did it the other way round, fitted the inverter and a pair of Leoch Pure Lead Carbon batteries last week.

This lockdown is costly isn’t it lol

 

[Trout bum]

i did it the other way round, fitted the inverter and a pair of Leoch Pure Lead Carbon batteries last week.

This lockdown is costly isn’t it lol

It certainly is expensive sooner we can get back on the road the better , but it's good to have the time to do all our upgrades and they will pay off hopefully , what make of inverter did you install.

 

[Al n Val]

It certainly is expensive sooner we can get back on the road the better , but it's good to have the time to do all our upgrades and they will pay off hopefully , what make of inverter did you install.

it’s a Giandle 2kw pure sine wave inverter, recommended by a mate, that and the batteries

^{_{Subscribers  do not see these advertisements}}