M&H

Thanks for the advice, Pete and Tony. I'll give the system another bleed and see if that makes a difference. I haven't changed filters since I started having problems back in October, when diesel was diluting the oil - hence the new injection pump. Excuse my ignorance, but what is the 'idle damper'? Is that what I'm calling the 'idle adjustment screw', or is this the nut for bleeding the pump at the top - as in the video?

Just to clarify. I set the idle in the 5-600 range, as per the manual, but it slipped down to a slower rpm. It hasn't done this since I last tightened the screw a couple of days ago, though, so that particular issue might be sorted now. Maybe.

I had a new injection pump installed on my 1.5 bmc. Since then, the idle speed's been erratic. At times it's dropped so low the engine's cut out. I've adjusted the idle speed screw on the pump to which puts it up to about 600rpm (I think - the guage isn't that accurate), but after things have warmed up the idle increases significantly, possibly 1000rpm. Any ideas what could be causing this, and possible solutions? RCR installed the pump and I've had the engineer back - but his only suggestion so far has been to play around wtih the adjustment screw.

Hello all -- I'm just about to replace my battery bank, but I also have a question about my charging system. We're planning to get either 270ah or 405ah capacity. Given our current power consumption (about 40ah/day), a new bank should mean that we'd always be above 80% SoC. If I understand things right, then that'll mean we won't need to bulk charge them -- they'll always be in absorption or float stages. We've got 200W solar panels, which work brilliantly right now. But we've also got an alternator on our BMC 1.5, which several engineers have seen and said it's a 'standard' 70a alternator. I've tested it regularly and never measured an output above 19a though! If we don't expect to bulk charge our batteries, would this still work effectively as the output would be lower? Could the low alternator output be related to the near-death condition of our current batteries? And about the battery bank - many have recommended getting a larger bank, but given our usage, is it worth it? Would it be easier to replace, say, 60a in a smaller bank, as some of the charging would be below 80% SoC, and so the batteries would accept a higher charge at the start? Also, wouldn't it be easier to get the bank up to 100% with a smaller bank? Many thanks!

I don't doubt the Smartgauge -- just my ability to interpret it. But I might just try what you suggest for comparison -- thanks!

Good question. I've got a very similar situation with my Smartgauge (just installed last week). Yesterday, nice sunny day, the solar panels got the batteries up to 100% during the course of the day from 68% in the morning. I checked at 9pm and they were still at 100%, but by 6am they'd dropped to 67%. Also, only the fridge running overnight. I've checked the current from the fridge quite regularly, which leads me to think it's under 40ah/24hrs. But then, this also suggests that the battery capacity is far less than 220ah. (I'm assuming that the % shown on the Smartgauge is the actual capacity rather than the claimed 220.) Are these batteries near-death, or am I missing something?

Thanks, PaulG! I had already bookmarked this page but haven't yet had a chance to read through it.

A bit of an update and few more questions! We had 200W solar panels installed during the week. We've also been running the engine a lot, and kept the fridge turned off. Now with the MPPT controller we can easily see battery voltage (although I understand that it won't give a reliable SoC), but it also indicates which phase of charging it's in - i.e. bulk, absorption, or float. What I take as a good sign is that this is usually in 'float' mode. Re: the fridge. It is a Lec with a Danfloss compressor (same as eggpie). I figured out how to insert the multimeter into the circuit of the fridge and measured the current as between 4.7-4.8A. Bearing in mind that I only turned on the fridge for the test, I don't know if that is an accurate reading of what it would draw on average. But to my mind that does suggest it's a fairly hungry beast. I'd like to know what people's thoughts are about that reading - i.e. could I get a reliable figure of daily usage from it? (e.g. 4.8*24hrs = 115.2 ah/day I hope that's not right ?! ) Certainly without the fridge, we'd be very comfortable power-wise. (Actually, I'd barely notice it's absence if it wasn't for the fact that any time I mention this to my wife, she grabs me by my collars and shouts, 'I NEED A FRIDGE!'.) On another point, a SmartGauge sounds like a great gadget and I'm going to get one, but I was also considering installing a shunt ammeter to measure the current from the batteries. Are these any good? On ebay, there seems to be ones priced 5-15 pounds -- e.g. this link -- am I looking at the right thing? And a final question... I've read that the alternator should be no less than 33% of total battery capacity, so if I have a 70A alt. and 220ah of battery, this suggests that I should not get a larger battery bank. But I've also read (on this forum, I think) that 70A is the max a BMC 1.5 can handle. So, assuming I stick to the alt I've got (and don't get a different way to charge batts), is it really wise to get a larger bank? I'm wondering if we could get by with our current charging system, possibly 330ah batts (to give a bit of a buffer), but a new and more efficient fridge.

Great info, everyone. Thanks again. My current thought is to: 1) Get a clamp meter as suggested to get a better measure of the charging system. 2) Look into a generator (w/ inverter charger) as a more effective charging strategy. I like the idea of double alternators, but the engine's placed way forward, and I doubt it'd be possible to install. 3) Get a bigger battery bank. 4) Get a smaller, more efficient fridge, but see how effective 2 and 3 are first.

OK, thanks everyone. I've switched off the fridge for now and will monitor the batteries for a day or two -- which I hope will give me a sense of their health and the draw the fridge was taking. It seems to me that sorting out a better charging system would be more important than more batteries, right? If so, does the choice of alternators available depend on the engine (we've got a BMC 1.5)? Would a double alternator be better than a single, more powerful alternator? Anyway, I got to go drink a lot of beer before it gets warm.

Many thanks, Bottle. I must say, this is probably the most helpful forum I've ever used. Those links look really useful, and answer quite a few other questions I'd been wondering about. Based on what the surveyor told me when we bought the boat, I'd assumed the fridge used around 40ah, which would be within our power-consumption budget. Looks like I'm fridge (and battery) shopping this week.

Thanks again! That does clarify things nicely. We're getting 200W solar panels, along with an MPPT regulator. I invested in a copy of Nick Calder's book, figuring that it would save me money in the long run. But I guess I'm a slow learner!

Thanks!

That's interesting to know about the Lecs -- when we bought the boat, the surveyor said it was a good fridge! It's clearly old though, so perhaps in its day. Not sure on your source of frustration there OldGoat but you're on the money - couple of hours a day, and longer cruising at the weekends. That said, we're getting solar panels fitted (this week!) too. Is there another way to charge batteries that you'd recommend? (we don't have shoreline connection.)

They're x2 110ah batteries. We only have LED lights. It's a Alde heater, but we didn't have it on. No TV, no inverter either. Since the last charge, we have probably had a light on for about an hour, the fridge, and the water pump a few times. That's about all the power we've used. Edit -- the fridge is a LEC, but I don't have a manual for it. I haven't figured out how to find out its power usage (I'm very new to this 'electricity' thing!).