Ring RSCDC30 - bulk charge, float mode and voltage drop?

[sb329]

Hi everyone. First off, I'll tentatively stick my head above the parapet and whisper that I do not own a VW! I actually have a self build Iveco but have found myself lurking on the forum and reading opinions and thoughts on the Ring B2B charger, and intelligent alternators

So I've now worked out that my 2014 Iveco does not have an intelligent alternator but that does leave me with an issue I will come to shortly.

First of all though, I've had the Ring fitted for around nine months. My setup is two Trojan T105 golf cart batteries, 200w of solar panels, a Nasa BM1 battery monitor, and the main consumers are a CRX80 Fridge, Propex, 24/7 dashcam, and my double din stereo has been rewired to the leisure system.

For the first few months I only had the solar panels feeding into the Ring, and I could leave the fridge on 24/7 and the batteries would be fully recharged each day. As my conversion progressed, I hooked up the vehicle battery to the Ring, using 50 amp cable and 40 amp fuses.

Then the issues started. Firstly, the Ring was replaced after I realised it would overcharge the batteries. It never entered 'Float' mode, instead it would stay in 'Bulk' and be pushing 8-10 Amps into the batteries at 15v, and after resting the batteries would be sitting at around 13.5v. This would happen either from the solar or alternator inputs.

After being replaced, it now enters 'Float' mode correctly However, the alternator charging still seems a bit erratic. Interested to hear from other owners... On starting the engine, the Ring will dump up to 20 amps into the batteries before cutting off, it will cut in again and provide short bursts three or four times before seemingly giving up. We are currently driving four hours across Scotland and when the wife is driving I've been nipping back to check the battery monitor, on one occasion I've seen it sitting steady at 21 amps but the other four times I've gone back its not been charging, just the occasional momentary blip from 12.4v to 13v and then off again. The blips are not long enough for the battery monitor to measure a change in amps. The batteries are sitting at around 50%/12.4v. I can change the Solar priority mode on the Ring but its overcast and only pushing about 3 amps from the panels!

 

[t0mb0]

I'm interested as I'm considering the ring unit myself.

Does solar mode still charge the batteries correctly? I'm wondering whether the previous faulty unit has actually overcharged and damaged the batteries?

Have you also tested the wiring for faults and is the unit set to the correct battery type?

Also, given you've got wet batteries, I assume they're topped up ok?

 

[travelvolts]

First remark that I would add is that the NASA BM1 is not brilliant but in terms of using it s a simple volt or ammeter then it does the job. Could there be a poor connection on the wiring to the BM1? Also, there was an unexplained break in production of the Ring RSCDC30 during April/May. Could there have been some underlying issues that they were resolving during this time? perhaps try another replacement if your supplier is willing.
I also echo the suggestion of checking the electrolyte in the Trojans, rapid charging does cost water!

 

[sb329]

Thanks guys.

Trojans were new six months ago and I caught the overcharging rather quickly as it only really became an issue with longer spring days when the solar started generating more power. I should check the water, thanks. Trojan recommend to do an equalise charge occasionally where the batteries will gas noticeably, so I'm sure they are OK.

Solar charging seems to work fine and regularly see 10 Amps (on both BM1 and the Ring display), just a few minutes ago we had a sunny spell and I saw 14.5A from the panels.

I had another poke about this morning and the Ring would charge from the vehicle at between 25 and 30 amps for a few minutes at a time. I got the multimeter out and noticed that the battery input terminals on the Ring were dropping from 14.4 to 13.3v when it was drawing current, so now wondering if my 8 metres of 50amp cable is suffering voltage drop and causing the Ring to cut out, or, is this just the feature where the b2b pulls the current down deliberately so it can draw maximum power from the alternator...

 

[travelvolts]

The Ring will take power from the vehicle battery, not the alternator, so power should continue to be drawn until the vehicle battery drops to 12.4 volts.

 

[sb329]

Aren't the B2B chargers meant to do something (presumably voltage related) to pull maximum current until the leisure battery is almost full? Otherwise the current would drop off like a split charge set up...

I also thought that although the b2b connects to the vehicle battery, it doesn't actually take power from it (except for a short period after the engine is stopped). The higher voltage from the alternator will arrive at the battery, and it and the Ring will draw what current they can scrounge/require. The lower the voltage of the battery, the more current will be drawn.

 

[travelvolts]

It should charge at constant current in the initial bulk phase and then switch to constant voltage for absorption phase before switching to float. B2B chargers work by pulling power from the supply battery which in turn causes the alternator to give power. There not controlled by alternator output as with a simple split charge system. It sounds as though yours might be faulty if it doesn't hold constant current, unless of course your battery is actually full!

 

[sb329]

Thanks . I'll rig up a temporary cable and see if I can get rid of this voltage drop to rule it out of the problem.

 

[travelvolts]

I'd double check all connections as well as these can be a source of VD too.