Club 80-90 Forums

Apologies if this combo has appeared before and I've missed it 'searching' !

A new leisure battery, Victron SuperAGM 60 ah (chosen for size and ability to cope with deep discharge, so blurb said !) and new VSR, Victron Cyrix-ct (chosen for option of override switch to 'close the relay for 30 seconds' to allow the leisure battery (LB) to be used as 'an emergency start assist' if the engine battery (EB) is flat - forget lights on !) has recently been fitted (not by me !) to my van. All sounded good in theory. A reading off the LB on Friday was a concerning 11.6V despite a couple of runs, albeit each only 40 miles round trip. This lead to reading the EB: 13.4V maxing out at 13.6V under some constant rev, and at the alternator 13.8V. The latter is a Bosch 14V 45amp; don't know how old. It now seems that this 'smart' VSR may only connect at 13.7V and so hasn't been/can't charge the LB with the prima facie, voltage available in the current set up

Has anyone had this experience ? A suggestion has been to change the alternator for a higher amp (Wiki offers a continuous demand calcuation); how big can physically be fitted ? What else can I look at, test, consider please ?

Thanks in advance.

The voltage is to low for the VSR to cut in. Check the alternator battery connections are clean and tight and the drive belt is tight. Then fit an unrated 14.2V or 14.4V voltage regulator pack to the alternator.

Thanks; I haven't been able to take another look yet, but will soon I hope ! I'm not at all engine savvy so sorry if it's a silly question, but can the regulator pack increase the voltage? How does it attach to the alternator and can you provide please a link to where I can buy one ?

Alternators can produce over 50V depending on how fast you spin them. The regulator switches off the alternator when it reaches a set voltage then switches it back on again when it drops, it does it many times a second so you get a stable voltage. It used to be 13.8V for older style batteries. modern technology batteries can tolerate a higher voltage charge so are now set at 14.2V-14.4V

https://www.ebay.co.uk/itm/ucb400-UCB-4 ... SwUKxYd9vW" onclick="window.open(this.href);return false;

It screws into the back of the alternator.

Thanks bigherb, that's great. I bought the item and it's just arrived ! Sorry again no engine sense; is the pic of the bottom of the alternator as mine seems to have a closed in (cap?) top ? ! Does the alternator have to be opened up to fit ?

It is in the opposite end of the alternator from the drive belt.

I think that pic is for an early alternator so yours might look different where the cables attach