House battery not charging when engine is running.

[reddingnative]

The 7622 manual is here: http://assets.bluesea.com/files/resourc ... 180180.pdf

Unless overridden, it automatically combines or separates the two battery sides according to these rules:

bluesea_7622.png

Thus if either side is connected to a charger, the two sides will be connected and both will get charged.

- If you're hooked to shore power, the engine battery will also get charged from your house converter.

- If you're boondocking, both batteries can get charged from the solar panel.

- If you're driving down the road, the house battery will also get charged from your engine alternator.

Thanks for explaining that, now I really understand the value of this relay. Very cool, thanks again.

[reddingnative]

Okay, so I finally took a look at that diagram. Ironically, one reason it took me so long is that my buddy just got a new RV, and so of course it has the "standard" RV charging system, which wasn't working at ALL for the boondocking we're doing, and we're in the process of planning out improvements, ordering parts, etc. But of course we're in the mountains without many tools, etc. Isn't that how it goes?

So, ignoring everything that isn't germane, and writing it down so it clarifies to me as well, you basically have a start (Ford) battery, a house battery, and then a couple of solenoids between them, plus a couple of switches. Exactly how those all work isn't totally important if you are just going to put in a 7622 (which is a great choice, as long as you are happy with bi-directional charging). Not saying you shouldn't be, just that it's a choice* (see more below).

So let's mentally say you remove all the wiring/components that deal with these functions. That looks like it would be the two large cables (4 gauge red from the start battery, 8 gauge red from the house battery, the two solenoids, the two switches and their associated wiring, and the collection of fuses).

I'm not sure how physically far apart your two battery banks are. Are they both under the hood? Long distances in 12 volt DC systems mean you want really chunky wiring (to avoid voltage drop).

Also (you probably told me this but I forget now, sorry!), if you want to self jump start, and you want a safe over-current protected (fuses or breakers) system (a GOOD idea since batteries store a lot of short-circuit power potential (for example, over 10,000 amps for the pair of house batteries my bud is putting in ), then your primary wiring (the big/main positive negative cable circle) needs to be able to be fused high enough to not blow under the starter's current.

So, come to think of it, can you say (or remind me if I have forgotten by now) of the answers to these questions?

1) What is the distance from your start battery to your house battery? In other words, if you ran a hose from one to the other (with all necessary twists and turns), how long would it be? I can probably estimate from the locations, once I know what they are.

2) Do you want to have self-jump start ability? Or only charge combine ability?

3) Do you want bi-directional charging (both sources can charge both banks)?

Ready to respond - it's semi-break time while we wait for some of buddy's components to arrive.

BG

*Bi-directional charging means that when there is a charging source on the start battery (typically alternator when driving), it will be automatically shared with the house bank. And when there is a charging source on the house bank (typically shore power, generator, or solar) it will be shared with the start bank. There are uni-directional relays (not the 7622 and not sure any Blue Sea ACR). That would typically mean that alternator power would go to your house bank, but house charging sources would not go to your start battery.

Ok, so I ordered the 7622 and I'll have a mounting spot after I remove the solenoid wired to the engine/house battery. The 7622 will connect right up and is within easy reach. For now, I'll use the existing 4ga wiring that was attached to the old solenoid for combining. About a 10 inch wire run from the engine battery(DS) and then however far it is to the house battery on the opposite side of the engine compartment(PS). The remote will fit, with a little panel trimming, in place of the momentary emergency power/start switch. I'll post some pics when I get the project going. Thanks for everything.

[Blue~Go]

I'm not clear whether or not you're wanting to be able to use the jump start function, but let's say you do (I would want it since you'll be so close to having it). Then it's a matter of how important it is to you to have the safety of overcurrent protection. It's very important to me, and I'd recommend it highly. Batteries can give up a lot of power very suddenly if there is ever a short (and in a moving vehicle...it's not totally out of the question).

Having the short distances (with both of your batteries under the hood) is great. If you size the wires to enable fusing (overcurrent protection) then you will have no problem at all with voltage drop (big bonus). If you know the draw of your starter, that would be great. Otherwise, we could go with the draw of the V-10 starter as a good ballpark. I find that the bare (bare!) minimum for fusing for self-jump-start is 200 amps, and 225 is better. What that means is you could juuuuust skimp by with 2AWG wire (by over-rating the fuse, which is sort of allowed although not my favorite thing), or you could use 1AWG (or larger) and comfortably fuse it.

I ran 1/0 AWG (one size larger than 1) but that's because with the house battery aft, it's at least a 16' run between batteries so voltage drop comes into play (also I don't tend to have 1 AWG on hand).

So upshot is, I would encourage you to go with a "full circle" cable run that you can fuse for the starter's draw. This would be the positive cable from Ford to 7622, the positive cable from 7622 to house, the negative cable from house to frame, and the negative cable from frame/chassis to Ford battery. One fuse would go on the positive terminal (or within 7") of each battery. I like the Blue Sea MRBF if you have the height (I do but I have the V-10 so layout is a bit different). These have enough AIC rating for a typical single battery, you don't need extra jumpers, don't need to figure out where/how to mount the fuse, and there is no unprotected wire.

[reddingnative]

I'm not clear whether or not you're wanting to be able to use the jump start function, but let's say you do (I would want it since you'll be so close to having it). Then it's a matter of how important it is to you to have the safety of overcurrent protection. It's very important to me, and I'd recommend it highly. Batteries can give up a lot of power very suddenly if there is ever a short (and in a moving vehicle...it's not totally out of the question).

Having the short distances (with both of your batteries under the hood) is great. If you size the wires to enable fusing (overcurrent protection) then you will have no problem at all with voltage drop (big bonus). If you know the draw of your starter, that would be great. Otherwise, we could go with the draw of the V-10 starter as a good ballpark. I find that the bare (bare!) minimum for fusing for self-jump-start is 200 amps, and 225 is better. What that means is you could juuuuust skimp by with 2AWG wire (by over-rating the fuse, which is sort of allowed although not my favorite thing), or you could use 1AWG (or larger) and comfortably fuse it.

I ran 1/0 AWG (one size larger than 1) but that's because with the house battery aft, it's at least a 16' run between batteries so voltage drop comes into play (also I don't tend to have 1 AWG on hand).

So upshot is, I would encourage you to go with a "full circle" cable run that you can fuse for the starter's draw. This would be the positive cable from Ford to 7622, the positive cable from 7622 to house, the negative cable from house to frame, and the negative cable from frame/chassis to Ford battery. One fuse would go on the positive terminal (or within 7") of each battery. I like the Blue Sea MRBF if you have the height (I do but I have the V-10 so layout is a bit different). These have enough AIC rating for a typical single battery, you don't need extra jumpers, don't need to figure out where/how to mount the fuse, and there is no unprotected wire.

Ok, I understand everything except "using the jump start function". I won't be able to begin this project for a couple of weeks, so thanks for the detailed information. Do you make up your own cables or???

[reddingnative]

[kdarling]

Red, you already have a jump (boost) solenoid. That's the one I thought about replacing with the Blue Sea, but hmmm. Have to think on that.

Question: in the diagram you said is yours, the other solenoid is used to connect the converter with the house battery.

If that's in the "Store" position (off), and you're on generator or shore power, do your coach interior lights etc still work? In other words, is the converter always hooked to the DC distribution panel?

(Mine is the opposite. The converter is always tied to the house battery only, and thus won't go to the distribution panel unless House power switch is on.)

[reddingnative]

Red, you already have a jump (boost) solenoid. That's the one I thought about replacing with the Blue Sea, but hmmm. Have to think on that.

Question: in the diagram you said is yours, the other solenoid is used to connect the converter with the house battery.

If that's in the "Store" position (off), and you're on generator or shore power, do your coach interior lights etc still work? In other words, is the converter always hooked to the DC distribution panel?

(Mine is the opposite. The converter is always tied to the house battery only, and thus won't go to the distribution panel unless House power switch is on.)

Thanks for the reply and questions, my owners manual "Power off switch does not shut 12V off when plugged into 110V." I can confirm that I have house power when the house power switch is off.

- If you look at my wiring diagram, that "house solenoid" when switched on, allows current to flow from the house battery to the convertor distribution panel for 12V circuits.

- That same solenoid allows charging current to flow to the house battery from the convertor via shore line or generator power.

With that said, once I install the 7622 w/remote in cab, in place of the "jump/boost" solenoid switch, I will operate like this:

- Set the 7622 remote to the "Auto". In theory, and I'm still digesting it's operation on Blue Sea website, it will charge the engine and house batteries based on those voltage parameters you posted.

- Set the 7622 the "On" position which will combine both batteries for "jump/boost". If I'm incorrect here let me know.

- Since the 7622 is bi-directional and with it set to the "Auto" position, I should be able to charge the house and engine batteries while using shore power or the generator. In order for this to work, the house solenoid RED Switch must be in the "In Use" position. That is the only way for the convertor charging current to reach the engine battery and after passing through the house solenoid to the house battery and then over to the 7622 for automatic charging of the engine battery.

- I have 2 volt meters in place. One in the cigarette lighter socket on the dashboard and the other one in the cigarette lighter socket in the house next to the water heater switch. It gives me a general idea of my battery voltage and charging current. When I reach the 12.4V range in the house, I know my house battery is at 75% and it's time to start charging or face much longer recharge time based of percent of charge.

So, you only have 1 solenoid mounted on the firewall? And a engine battery and house battery in the engine compartment?

If so, the way I understand it, you may have a Ford factory installed wiring harness for your auxiliary/house battery with relay for charging both batteries. That relay with harness would be located as you indicated, in front of the engine battery, behind the headlight. If you find the main positive lead on the house battery and follow it back towards the engine battery you might find the relay if it's wired that way.

[kdarling]

- Set the 7622 remote to the "Auto". In theory, and I'm still digesting it's operation on Blue Sea website, it will charge the engine and house batteries based on those voltage parameters you posted.

- Set the 7622 the "On" position which will combine both batteries for "jump/boost". If I'm incorrect here let me know.

Yep, all sounds good to me. The fact that it's already used for boost is why I'm not sure it needs larger wires.

Also glad you have some meters. It help to be able to see in realtime what's going on.

So, you only have 1 solenoid mounted on the firewall? And a engine battery and house battery in the engine compartment?

Yep, apparently I have the Ford factory installed automatic charging when engine is running. When I start my engine, I immediately see the charging effect on my house battery.

But I'd sure love it to go the other way as well. Recently my engine battery was going dead, which has got to be because of the new radio I installed in the coach. I've had to disconnect its memory wire.

[Blue~Go]

Argh! So of course I was 85% of the way through a detailed reply to kdarling's question about "why it needs larger wires" when I realized I had forgotten to plug in and my laptop battery died. So aggravating.

I will re-write this later. The short answer is that unless you have larger wire you cannot provide OCP (that is, Overcurrnet Protection, e.g. fuse or breaker). Without OCP you have a big problem waiting to happen if there is ever a short (and what could possibly go wrong in a moving vehicle with lots of metal and a chassis ground?). Just as one example, a Lifeline Group 27 battery (using this example because they publish the stats) can discharge 3,374 amps in a short circuit situation. If the circuit is not protected something bad is very likely to happen. Smaller wire can only be protected by smaller fuses and those will blow every time you self-jump start (or every time you alternator charge the house bank if the wire is small enough). This is likely why Chinook did not provide OCP to this circuit (that's the "solution" to using wires too small to protect, and is often used in RV's. Most people get lucky and nothing happens.

But while it's one thing to have an existing circuit be this way, I have a hard time purposely installing a new one without bringing it up to safe standards. So I improve as I change things. Figured reddingnative might want to as well, especially considering the large amperages involved.

In my previous reply I used examples with numbers/wire gauges/ampacity ratings, etc. I'll come back and do that again when I cool off from the "lost" post

[reddingnative]

- Set the 7622 remote to the "Auto". In theory, and I'm still digesting it's operation on Blue Sea website, it will charge the engine and house batteries based on those voltage parameters you posted.

- Set the 7622 the "On" position which will combine both batteries for "jump/boost". If I'm incorrect here let me know.

Yep, all sounds good to me. The fact that it's already used for boost is why I'm not sure it needs larger wires.

Also glad you have some meters. It help to be able to see in realtime what's going on.

So, you only have 1 solenoid mounted on the firewall? And a engine battery and house battery in the engine compartment?

Yep, apparently I have the Ford factory installed automatic charging when engine is running. When I start my engine, I immediately see the charging effect on my house battery.

But I'd sure love it to go the other way as well. Recently my engine battery was going dead, which has got to be because of the new radio I installed in the coach. I've had to disconnect its memory wire.

Ok, so you already have part of your solution if you want to use the 7622. You could disconnect the factory harness when you are ready to install the 7622. You would then replace your emergency start solenoid with the 7622 because the wiring is already in place and I'm assuming that solenoid is mounted with some "L" brackets next to the engine battery. Should be 4ga wire coming off each side of the solenoid and enough room to mount the 7622 and attach the existing wiring. The 4ga meets the minimum requirement for the 7622 specs, but I agree with using larger wire, and all the wire runs are short. I'm trying not to break the bank, but I want to be safe as well.
The 7622 remote will install using the hot wire from the emergency power switch which will be removed. I measured and I think I can mount the remote next to the house switch with a little trimming.

As to why you have to have your house power switch turned on for the shore power to work, I'm not sure. I'm going to double check my switch and make sure what I told you is correct.