Hopefully sensible upgrade options for Charging system....

[domf]

I have read every battery/charging thread I can find on here and other Forums - so hopefully not just rehashing questions that have already been obviously answered.

 

We are the new owners of a 2016 Swift Bolero 744, which has two new LB6110L PLATINUM LEISURE PLUS batteries, we recognise these are far from the best leisure batteries. We are delighted with the motorhome but, having spent some time investigating the electrical system, recognise that it leaves quite a lot to be desired.

 

This is fitted with a Sargent EC620 display, Sargent EC651 Power Supply, Sargent PX300 Charger and Sargent Solar regulator. I believe the van was originally delivered with one battery, but with a battery box capable of holding two, with the second being connected to the first with undersize wiring and a connection from the second battery to the ALKO chassis.

 

My wife and I both use E-bikes with Bosch motors/batteries - we want/need the ability to to topup the charge on these when off mains power. Note - I do not expect to be able to charge two flat 625Wh 36V batteries without mains or a long drive, however if at (say) 75% would like to top up so we do not suffer "range anxiety" when using the next day.

 

Issues:

1) The voltage drop from Vehicle Battery to Leisure batteries when charging is >0.5V

2) The voltage when mains charging is also significant - with 14.1V showing on the Sargent display at 8A is measure 13.6A at the leisure batteries.

3) The batteries appear to be "not great" - but given they are new I plan to live with them for now

 

Upgrade thoughts:

1) Wiring from the alternator to leisure batteries with additional split relay. I am undecided whether to run 16/25mm wiring in addition to that present or to install B2B charger with the same wiring which I also take the solar into (120w) - perhaps with a CTEK D250SE 20A . I would appreciate thoughts on these options from those more knowledgeable than myself!

 

2) Upgrade the battery charger and move it closer to the batteries with appropriate wiring - I would appreciate thoughts on this and battery charger recommendations.

 

3) Inverter. The Bosch bike battery charges are rated at 2A but interestingly both pull more than this. We are looking to install a NDS 1500i inverter and use this for topup. This clearly needs the wiring upgraded between the batteries and will be located as close to the batteries as possible on a fused connection.

 

We would like whatever we do to leave the door open to move to Lithium, but do not plan to do this at this stage.

 

Background Information:

1) The alternator is 150A

2) although we have only had the van a short while, but we have spent just over 4 weeks in it, most of which was in Germany and Italy. We have discovered we clearly enjoy wild camping more than staying on one site - though recognise the convenience of sites or charging and fluid replenishment and disposal...

 

Dom

[colin]

Just had a look at our chargers, whilst they are rated at 2amp this is for 36v, so at 12v you triple that, i.e. 6amp, or 72watt, we use a 300w invertor to charge the batteries, but note that on the last thread on Bosch chargers a 12v one is available which will be a tad more efficient.

A little and often is always the best way of charging them, even on mains it's not good practice to fully discharge then fully charge.

 

[arthur49]

On improving leisure battery charging check out this webpage:-

 

http://www.aandncaravanservices.co.uk/add-a-second-battery.php

 

I did as the late Allan Evans suggests by improving the cabling and split charge relay and got 14.34v at the leisure batteries whereas before doing this, the voltage was circa 13.9v from memory. Improved charging massively, no need for a B2B.

 

 

[spirou]

If you plan on moving to lithium at any point then you really should install a B2B. Obviously one that supports it, not all do. I would recommend it in any case although it's not strictly necessary for every lead-lead combination. Not sure why you'd wire to solar output there though?

 

Obviously going up in wire size or two or three will help with voltage drop. You don't say what you have now. Also consider you might be limited by the size your connectors can accept. 25mm2 might be a tad optimistic in some cases, also not that easy to route through. Moving any charging source closer to batteries also helps.

 

If you're looking for brands to explore options: Victron, Mastervolt, Votronic, Schaudt

[arthur49]

spirou - 2020-10-03 4:31 AM

 

.............. Also consider you might be limited by the size your connectors can accept. 25mm2 might be a tad optimistic in some cases, also not that easy to route through. Moving any charging source closer to batteries also helps.

 

 

Yes. I ran a 25mm cable from front to back of van. Not easy ...................

 

If I were to beef up wiring again I'd run 2 x 10mm and it makes crimping connectors easier

[domf]

 

Thank you all.

 

This has helped my thinking - the logistics of running 2 x 10mm rather than 1 x 25mm in particular! Are there any pros and cons about running one each to the two batteries as opposed to both to one battery?

 

 

 

Dom

[mikefitz]

Hi Dom,

 

If you wire chargers direct to the batteries you will get greatly improved charging but will have incorrect information on the 620 display regarding charging currents.

 

The solar regulator built into the Sargent system is a low cost PWM controller. Replacing this with a quality MPPT controller wired direct to the batteries, with a maximum cable run of 2m from controller to battery, will improve things considerable. Selecting a unit that would allow additional panels to be added at some stage should be considered. Since you will be loosing current information I suggest selecting a controller with Bluetooth or remote display.

 

As regards alternator charging I suggest a battery to battery charger rated at 30 A or 60 A. The higher current option may be useful considering the high power inverter you intend fitting. The B to B should be installed near the leisure batteries. And voltage drop on the cable from engine battery will be compensated for by the B too B. However the manufactures specify cable size, and its probable the existing cable will need to be replaced or a second cable run in parallel.

As with the solar charger having a remote display or Bluetooth capability is useful.

 

I dont recommend the Ctek 250, its not a particularly good charger.

 

The chargers you select should have the built in options for different battery types and ideally user options to program optimum charge values.

 

Chargers from Victron and Votronics are considered reliable and well designed units. My personal preference is for Victron chargers with Bluetooth. Not only does this give you voltage current and power information with history, all setup and software update is via the phone app. All Victron products have a 5 year warranty.

 

Battery monitoring is useful and the Victron Smart Shunt is a cost effective solution.

 

The voltages you measured show significant voltage drops that must be compromising battery charging.

Although your batteries may not be the most desirable, with correct charging they should give a year or two useful life. All the Victron and Voltronic chargers can be used with all battery types including lithium.

 

With improved alternator charging having the E bike chargers operational whilst driving effectively gives 'free' charging as it does not drain the leisure batteries.

 

Any fusing on the batteries must be up graded with midi or mega link fuses in their holders. Since you will have a number of connections to the leisure battery I suggest using a fuse distribution holder. It will have a mega fuse for the inverter and midi fused for the chargers.

https://www.altecautomotive.co.uk/mega---midi-fuse-distribution-box-altfh260158--01-closed-back-5856-p.asp?gclid=EAIaIQobChMIvL37tvyg7AIVwuvtCh3aQgLJEAQYAiABEgIe8PD_BwE

 

I have no connection with this company other than a customer. Onboard Energy are a main Victron dealer with good support and using the discount code, JONOPROMO will get a 15% discount.

 

Mike