[size=6]Just replaced 10 year old batteries on Sulito, Parker 325

New batteries read 12.70 o Voltameter, all fully charged

But on the panel it now reads 5.7 V

Has anyone experienced this

Now dont know the real volts unless I expose the batteries and used a voltameter

Anyone else have this?

Regards

Barry

Sulito 39

Very strange Barry. I noticed the voltmeter in the switch panel deviates some tenth of a volt from my USB ports that have a built-in voltmeter, but the voltage on Solito deviates so much more. I can’t explain that other than a bad contact.

I had the same Barry. Bought nice big new batteries when I refurbed Blue Moon and the moment we connected them the original voltmeter went bonkers and now reads a range of numbers which only rarely relate to the actual voltage. I didn't mind too much as at the same time I put in one of those NASA battery monitors, but now I do as the monitor itself has just given up after just five years.

I am pointedly not buying another NASA one to replace it but if you did decide to add a monitor instead I noticed that they do a Bluetooth version that would save you having to mount a new device on the panel. Or of course there are loads of simple and small voltmeters.

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Hi Peter and Barry,

Do you have separate start and household batteries? On Surprise I have two different batteries from the previous owner. One is a start battery and one is a household battery. However, both are one the one switch on the front the port couch. I have to make sure nobody sets the switch to ‘both’.

How do you manage both batteries?

I’d like to separate both circuits and place a large LFP battery (314Ah) under the starboard couch. All LFP batteries I’ve seen so far are too high to put them in the current place under the port couch, but not all Parker 325/335 have the same battery compartment under the port couch. I saw Mike Baldwin (#46) has one large compartment, where Surprise (#45) has two fixed compartments

Hi Dirk

Yes, I have 2 x 120Ah house batteries under the port settee and 1 x 120Ah start battery under the starboard settee. I also have the old-fashioned rotary switch 1/1+2/2/off which dictates which bank is being charged and supplying current, the key thing being isolating the start battery when not charging so that it is always topped up. I believe Mike has the rather smarter version with a diode-based controller which does the selection automatically. I don't know what a lithium set-up would look like but I do hear that it's not recommended as a DIY installation as the charging requirements are quite different.

Hope that helps

Peter

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Well Peter, in my previous boat, a Hurley 800, I build an LFP battery with a BMS myself. It’s not that difficult, but indeed the charging characteristics are different. I used a Victron IP22 to charge the LPF battery when on shore power. That would last for a week. Alternatively I could have chosen for DC-DC converter to limit the charging current to the LFP battery.

The start battery was charged by the alternator. A