Second leisure battery debate / challenge.

[colinm]

I've got a gas cooker with Burners and Grill in the motorhome, but I still use an electric toaster

The best grill we've ever had in a motorhome was one in a rented van in NZ 30+ years ago, it had what I can only describe as a 'super sur' type matrix on the grill, gave an even heat across the whole grill pan.

 

[molly 2]

When we first got our van a swb relay it only had a 110 lead battery and a 12 volt cool box would only last a day. So changed battery to 200ah lithium fitted a 50 litre compressor fridge a 235 w solar panel and a b2b with mppt solar charger and it works perfectly we where away last week for 7 nights and didn't need ehu our solar charger works even if it's raining and we used our inverter most days.i would check what type of b2b and solar charger you have and upgrade if needed as it makes a lot of difference and recommend changing your battery to lithium

You got it all right Steve love your van Bazz

 

[molly 2]

Just my own opinion a voltage reading is an unreliable way of monitoring a battery a shunt type amp meter is more reliable and accurate

 

[Drover]

Way to low for standard lead acids, think mine on 2 90ah goes down to 12.2 at lowest.

My fault. I should have checked.. 3 settings
11:2 11:5 and 12:2.. it's at 12:2 from the factory...

 

[trevskoda]

My fault. I should have checked.. 3 settings
11:2 11:5 and 12:2.. it's at 12:2 from the factory...

Yes keep your eye on batteries to make them last, many folk with no knowlage distroy the batteries and or dont have proper on board smart chargers or solar with a mppt regulator, they then run the batts down to the last flicker of life and then wonder why they fail, like every thing in lifr its best to do some study and background into a hobby or in fact everything we use, other wise you will get stung.

 

[Deleted member 86180]

Our van came with two 110ah lead acid, a 12v 43w fridge but no solar. Useless off grid. Had 1x100 pv fitted, not good enough either, so had second 100pv fitted. Now fine but not in winter when we have often to run the engine on tickover to provide a boost. A battery to battery charger would be a good idea for very fast engine charging, but have not invested so far as they are expensive. We don't have room for any more fixed pv, but portable is a possibility i guess.For offgrid pv 200w+ is essential plus min 200ah+ of bats, lithium if poss. If you want to use 230v equipment then yoy have to go to maybe 400wpv plus large lithiam capacity plus BtoB .
Just my opinions gatheted over the last mant years which not everyone will second.

So you’re the one that wakes everyone up in the morning running your engine for power! Get a decent dc to dc and give people some extra sleep

 

[Deleted member 86180]

Should have read the thread a bit more before commenting, what Brand of B2B were you using that overheated ?

I hadn't looked at Renology before, Sterling and Victron look good and I have bought and used Victron gear in other van projects.
Also having an MPPT built into the B2B seems odd, I wouldn't have thought you would get as good an output from both Solar and engine as you would with two separate devices, but maybe I am wrong. Also a single point of failure.

Another van that I looked at, that I am contemplating buying, had a https://www.donrowe.com/KISAE-DMT1250-Abso-50A-DC-DC-Battery-Charger-p/dmt1250.htm and 350 watt Solar, and maybe 300 AH leisure and they had issues with charging, similar to what this thread is about, which seemed odd to me. However, not sure on quality of panels. Do you know anything about those DMT1250 chargers, the brand wasn't Kisae, was something else. but the same unit ?

Ok you asked, with our new van I’ve gone Renogy whole hog. The beauty of having an MPPT built in to the dc to dc charger is two fold. When you have solar and are stationary for a while, it’s a very effective controller. However it speaks to the dc to dc - Bluetooth and will charge your starter battery when the leisure is nearly full (great feature during winter months). The literature says that it will share 25 watts from the solar and the same from the dc to dc. In reality with little solar (we can’t produce that much in summer) while driving you’ll charge at between 46 & 50 amps/hour. Another good point is that one unit is a space saver.

Get your point about single point failure but if your separate dc to dc charger or solar controller fails during the winter you’re pretty messed up anyway. The 50 amp Renogy combined unit is very cost effective, very accurate on claims (no overheating or choking with background heat). We run a low watt kettle and toaster while touring through a 2000 watt Renogy inverter (both together), plus it’s a self switching pure sine inverter (pretty clever for the non technical minded among us like me. We use between 60-70 amps/day while touring, saves loads of lpg. No problems even with a few days stopping off.

That is combined with a 200ah Renogy lifepo4 smart battery - obviously

 

[JonnoR]

Hi All,
Am looking to move forwards with this and have decided to go with a B2B charger am thinking of this product - https://www.roadpro.co.uk/product/0...2v-40a-battery-to-battery-charger-c8221/C8221 - does anyone have any experience with this bit of kit or can they suggest something that is as intelligent / good for me to consider.
Many thanks.

 

[wildebus]

Hi All,
Am looking to move forwards with this and have decided to go with a B2B charger am thinking of this product - https://www.roadpro.co.uk/product/0...2v-40a-battery-to-battery-charger-c8221/C8221 - does anyone have any experience with this bit of kit or can they suggest something that is as intelligent / good for me to consider.
Many thanks.

NDS is a good make and you will have a quality charger there I would think (not used on of these, but based on brand).
However, that is a fair old price there and there are other good quality choices significantly cheaper (but tend to be in the 30A range admittedly)

 

[merl]

Hi All,
Am looking to move forwards with this and have decided to go with a B2B charger am thinking of this product - https://www.roadpro.co.uk/product/0...2v-40a-battery-to-battery-charger-c8221/C8221 - does anyone have any experience with this bit of kit or can they suggest something that is as intelligent / good for me to consider.
Many thanks.

Be aware that some batteries have a maximum charge current limit and 40A could exceed that.
For instance my Leoch lead carbons have a max charge current of just over 20A. I have 2 batteries so it's within limits of my Renogy B2B which is rated at 40A but it has the option to remotely toggle that to 1/2 power @ 20A so ,the Renogy units have some adjustability re charge rate, this flexibility could prove useful as your system evolves.

 

[JonnoR]

NDS is a good make and you will have a quality charger there I would think (not used on of these, but based on brand).
However, that is a fair old price there and there are other good quality choices significantly cheaper (but tend to be in the 30A range admittedly)

Thanks for that any suggestions on other more cost effective B2B chargers.

 

[JonnoR]

Be aware that some batteries have a maximum charge current limit and 40A could exceed that.
For instance my Leoch lead carbons have a max charge current of just over 20A. I have 2 batteries so it's within limits of my Renogy B2B which is rated at 40A but it has the option to remotely toggle that to 1/2 power @ 20A so ,the Renogy units have some adjustability re charge rate, this flexibility could prove useful as your system evolves.

Yes my concern was the charge rate and damaging the battery but according to the manufacturer / distributor this product has intelligence on board to determine the best charge curve to use taking into account, solar, EHU etc. Do the other manufacturers (Renogy etc) have this type of intelligence

 

[Borders2]

Jonnor? I'd listen carefully to Wildebus as he is extremely experienced and competent, and I say this from personal experience and expenditure. We have no power issues due to the gentleman's excellent work. I would politely suggest that you arrange to meet him. Best thing we did.

B2

 

[wildebus]

Thanks for that any suggestions on other more cost effective B2B chargers.

The ones I am familiar with and would use are either the Victron Orion-Tr Smart 30A (non-isolated), or the Ablemail AMC 30-12-12 30A B2B.

The Orion is more 'user friendly' as a self-installation as you can configure it via the excellent Victron Smartphone app.
The Ablemail is a more capable and robust unit but you would generally need to have it pre-set for your setup (just tell the supplier what batteries you have, etc, and it can be set to your needs) or you can get a Bluetooth dongle for it, but that is around £75 on top.

Shout out to Alpha Batteries which can supply the Victron one at a great price with the forum discount.
The Ablemail AMC is available direct from Ablemail in Manchester where the units are designed, actually BUILT (built in the UK, not in some far east factory) and supported. They do have a number of dealers that resell as well, but you would want to check they will configure to your battery type before shipping.

There are of course other brands and models out there I could list, but I prefer to only discuss ones which I have personal experience of and would recommend.

As it happens, I fitted an Ablemail AMC just yesterday in a camper that also had an NDS solar controller

 

[merl]

Yes my concern was the charge rate and damaging the battery but according to the manufacturer / distributor this product has intelligence on board to determine the best charge curve to use taking into account, solar, EHU etc. Do the other manufacturers (Renogy etc) have this type of intelligence

The charge curves are the charge curve profiles for various battery types, any decent B2B will have these settings which you set according to whatever type of leisure battery you're using.
I've just had a quick look through the spec and the NDS does have some nice features (which you'll pay for of course) that exceed my Renogy unit such as a bypass option so that the unit can be bypassed and switched out if it breaks down, ,(it will need connecting accordingly to allow this option)it does also have the ability to limit the output to 1/2 power so 20A in this case but that is something you set at the unit and can't be toggled remotely like the Renogy which was a feature that I personally needed. The NDS also has better connectivity to monitor what it's doing by connecting to a central hub if that sort of thing floats your boat.
I paid just over £100for my Renogy but there is always a risk involved when going cheap, I was prepared to accept that risk mainly because I have the ability to repair it myself if/when it breaks down and I felt that Renogy were probably at the upper end of the budget market ( I can replace it 3 times for the cost of the NDS)
I think you're doing the right thing in getting as much info as you can before forking out, you'll probably find that if your installer is also supplying the B2B he'll stick with a higher end unit ( Victron is a favourite) due to future potential warranty issues.

 

[Stonies13]

Hi All,
Still fairly new to the MH/CV way of life and tbh loving it.

I have a quandary, so just returned from a two week trip around the highlands and islands of Scotland. TBH I am struggling with the leisure battery life (the van and battery are brand new). We want to go off grid for a few days (2-3 tops) at a time and the highlands lend themselves well to this.

However I was finding that the LB (110Ah) would not give us sufficient life. We have a 100W 650wh solar panel but for the first three days in Glen Coe all we saw was rain and no sun, so the LB would never get sufficient to keep it charged up. We even had to resort to driving around for an hr to try and out some juice back into the battery from the engine, but it never really got back up to full strength until we attached it to the EHU for a couple of days. Even longer 2-3 hr drives never saw it back to 13v.

I have asked the coachbuilder who fitted out the van (Peugeot Boxer) to add a second battery but it seems there is no space and they are telling me this cannot be done.

The fridge is the biggest consumer of electric, its a 12v with a tech sheet quoted 3.8A draw, we have LED lights and a Truma - I guess, water pump. Just doing the simple calcs the battery if receiving little or no solar would only last a max of 28hrs (taking it down to dangerous charge levels - which I am not prepared to do) and that is just the fridge alone. We ended up on a few occasions decanting water into water bottles and using torches for light at night. So may as well go back to camping.

Is there anything I am doing wrong OR am I missing something with respect to the charge. I have to say that the van is at home on my drive and the LB charge sitting at 13.4v today with a sunny day.

What are the other solutions available to me to give me extra off grid life. Not really looking to go down the generator route.

Thoughts please.

Many thanks
Jon

We had a 150 amp lithium battery and 3000 inverter. We have never looked back. Wild camping is like being at home. You can use all the plug sockets. Hairdryer. Crockpot. TV, Toaster. Look into the cost it will pay for itself as you won’t have to go on sites anymore.

 

[1 Cup]

Can't fit extra battery ! Is that a weight thing = 3500kgs

 

[JonnoR]

Can't fit extra battery ! Is that a weight thing = 3500kgs

No space, only allowable space converter said could not use due to ventilation issues and it would not be immediately near the other battery (there is a space compartment above the existing battery I thought could be used).

 

[JQB]

It's all a bit tricky TBH - I am looking now for a new Van and have been looking at a few. I know a little about Solar and Electrics as I have done some work myself but by no means am I an expert.

Today I saw a Van that had 2 90AH batteries, 400W Solar and a Renology DC/DC with an MPPT built into that. The guy had no shore power input and was fine with that set-up for two weeks in lake District area, not that sunny usually.

So you have two major issues as have been talked about above, not enough battery capacity and IMO not enough Solar capacity either. There may be other considerations to factor in like what sort of charger works from the engine side, is it B2B or a split charge relay because from what I have read up and know you get a better charge, more throughput % better Amps into the leisure side if you have a B2B rather than a SCR. Other factors are cable dimensions, quality of the battery, quality of the solar. There are larger capacity batteries available which may fit in your van set-up or an alternative might be to get something like this https://uk.jackery.com/pages/plus-series-event

Hope that is of some help

I found that with a 12v 43w (when running) fridge, truma, pump, leds etc, 2x100ah LA battery + 1x100w PV was barely enough in mxd summer weather, and not much use in winter. Now with 2x100w PV it's mostly ok in summer, but days when hvy cloud and rain persists & if not on the move i may have to run the engine just on tick over. In winter even in southern spain it's a struggle because of short days and heater use. Iv'e just had to replace the old batteries, bought AGM sealed this time so no more having to top up. Sounds like you could have to up your PV, 300w if poss i think, and go lithium for far more power in the ssme space + suitable charging equip. Expensive.

 

[1 Cup]

I put my battery's x2 in the shower wall the end of summer this year 2023 but they cost £1500, lithium 280ah cells x8 JK bms included in that price from S Wales, plus70mm wire and crimp connection's they don't need ventilation like wet battery's.

Battery's stacked on there sides, encased in 4 by 2 wood so wall is 10cm thick with 18 mm ply on the heavy side and 12mm in the frame the back as lid

From start up in a crate to done and coverd